TY - JOUR A1 - Dietl, Alexander A1 - Prieschenk, Christine A1 - Eckert, Franziska A1 - Birner, Christoph A1 - Luchner, Andreas A1 - Maier, Lars S. A1 - Buchner, Stefan T1 - 3D vena contracta area after MitraClip© procedure: precise quantification of residual mitral regurgitation and identification of prognostic information JF - Cardiovascular Ultrasound N2 - Background Percutaneous mitral valve repair (PMVR) is increasingly performed in patients with severe mitral regurgitation (MR). Post-procedural MR grading is challenging and an unsettled issue. We hypothesised that the direct planimetry of vena contracta area (VCA) by 3D–transoesophageal echocardiography allows quantifying post-procedural MR and implies further prognostic relevance missed by the usual ordinal scale (grade I-IV). Methods Based on a single-centre PMVR registry containing 102 patients, the association of VCA reduction and patients’ functional capacity measured as six-minute walk distance (6 MW) was evaluated. 3D–colour-Doppler datasets were available before, during and 4 weeks after PMVR. Results Twenty nine patients (age 77.0 ± 5.8 years) with advanced heart failure (75.9% NYHA III/IV) and severe degenerative (34%) or functional (66%) MR were eligible. VCA was reduced in all patients by PMVR (0.99 ± 0.46 cm\(^2\) vs. 0.22 ± 0.15 cm\(^2\), p < 0.0001). It remained stable after median time of 33 days (p = 0.999). 6 MW improved after the procedure (257.5 ± 82.5 m vs. 295.7 ± 96.3 m, p < 0.01). Patients with a decrease in VCA less than the median VCA reduction showed a more distinct improvement in 6 MW than patients with better technical result (p < 0.05). This paradoxical finding was driven by inferior results in very large functional MR. Conclusions VCA improves the evaluation of small residual MR. Its post-procedural values remain stable during a short-term follow-up and imply prognostic information for the patients’ physical improvement. VCA might contribute to a more substantiated estimation of treatment success in the heterogeneous functional MR group. KW - percutaneous mitral valve repair KW - MitraClip KW - 3D echocardiography KW - vena contracta area KW - six-minute walk test KW - NT-proBNP KW - prognosis KW - functional mitral regurgitation Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-225318 VL - 16 ER - TY - JOUR A1 - Allert, Stefanie A1 - Förster, Toni M. A1 - Svensson, Carl-Magnus A1 - Richardson, Jonathan P. A1 - Pawlik, Tony A1 - Hebecker, Betty A1 - Rudolphi, Sven A1 - Juraschitz, Marc A1 - Schaller, Martin A1 - Blagojevic, Mariana A1 - Morschhäuser, Joachim A1 - Figge, Marc Thilo A1 - Jacobsen, Ilse D. A1 - Naglik, Julian R. A1 - Kasper, Lydia A1 - Mogavero, Selene A1 - Hube, Bernhard T1 - \(Candida\) \(albicans\)-Induced Epithelial Damage Mediates Translocation through Intestinal Barriers JF - mBio N2 - Life-threatening systemic infections often occur due to the translocation of pathogens across the gut barrier and into the bloodstream. While the microbial and host mechanisms permitting bacterial gut translocation are well characterized, these mechanisms are still unclear for fungal pathogens such as Candida albicans, a leading cause of nosocomial fungal bloodstream infections. In this study, we dissected the cellular mechanisms of translocation of C. albicans across intestinal epithelia in vitro and identified fungal genes associated with this process. We show that fungal translocation is a dynamic process initiated by invasion and followed by cellular damage and loss of epithelial integrity. A screen of >2,000 C. albicans deletion mutants identified genes required for cellular damage of and translocation across enterocytes. Correlation analysis suggests that hypha formation, barrier damage above a minimum threshold level, and a decreased epithelial integrity are required for efficient fungal translocation. Translocation occurs predominantly via a transcellular route, which is associated with fungus-induced necrotic epithelial damage, but not apoptotic cell death. The cytolytic peptide toxin of C. albicans, candidalysin, was found to be essential for damage of enterocytes and was a key factor in subsequent fungal translocation, suggesting that transcellular translocation of C. albicans through intestinal layers is mediated by candidalysin. However, fungal invasion and low-level translocation can also occur via non-transcellular routes in a candidalysin-independent manner. This is the first study showing translocation of a human-pathogenic fungus across the intestinal barrier being mediated by a peptide toxin. IMPORTANCE Candida albicans, usually a harmless fungus colonizing human mucosae, can cause lethal bloodstream infections when it manages to translocate across the intestinal epithelium. This can result from antibiotic treatment, immune dysfunction, or intestinal damage (e.g., during surgery). However, fungal processes may also contribute. In this study, we investigated the translocation process of C. albicans using in vitro cell culture models. Translocation occurs as a stepwise process starting with invasion, followed by epithelial damage and loss of epithelial integrity. The ability to secrete candidalysin, a peptide toxin deriving from the hyphal protein Ece1, is key: C. albicans hyphae, secreting candidalysin, take advantage of a necrotic weakened epithelium to translocate through the intestinal layer. KW - Candida albicans KW - candidalysin KW - host cell damage KW - host cell invasion KW - intestinal barrier KW - necrosis KW - translocation Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-221084 VL - 9 IS - 3 ER - TY - JOUR T1 - \({ZZ}\) -> l(+)l(-)l '(+)l '(-) cross-section measurements and search for anomalous triple gauge couplings in 13 TeV \({pp}\) collisions with the ATLAS detector JF - Physical Review D N2 - Measurements of ZZ production in the l(+)l(-)l'(+)l'(-) channel in proton-proton collisions at 13 TeV center-of-mass energy at the Large Hadron Collider are presented. The data correspond to 36.1 fb(-1) of collisions collected by the ATLAS experiment in 2015 and 2016. Here l and l ' stand for electrons or muons. Integrated and differential ZZ -> l(+)l(-)l'(+)l'(-) cross sections with Z -> l(+)l(-) candidate masses in the range of 66 GeV to 116 GeV are measured in a fiducial phase space corresponding to the detector acceptance and corrected for detector effects. The differential cross sections are presented in bins of twenty observables, including several that describe the jet activity. The integrated cross section is also extrapolated to a total phase space and to all standard model decays of Z bosons with mass between 66 GeV and 116 GeV, resulting in a value of 17.3 +/- 0.9 [+/- 0.6(start) +/- 0.5 (syst) +/- 0.6 (lumi)] pb. The measurements are found to be in good agreement with the standard model. A search for neutral triple gauge couplings is performed using the transverse momentum distribution of the leading Z boson candidate. No evidence for such couplings is found and exclusion limits are set on their parameters. KW - Parton Distributions KW - Events Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-225844 VL - 97 IS - 3 ER - TY - JOUR A1 - Sperlich, Billy A1 - Hahn, Lea-Sofie A1 - Edel, Antonia A1 - Behr, Tino A1 - Helmprobst, Julian A1 - Leppich, Robert A1 - Wallmann-Sperlich, Birgit A1 - Holmberg, Hans-Christer T1 - A 4-week intervention involving mobile-based daily 6-minute micro-sessions of functional high-intensity circuit training improves strength and quality of life, but not cardio-respiratory fitness of young untrained adults JF - Frontiers in Physiology N2 - The present study was designed to assess the psycho-physiological responses of physically untrained individuals to mobile-based multi-stimulating, circuit-like, multiple-joint conditioning (Circuit\(_{HIIT}\)) performed either once (1xCircuitHIIT) or twice (2xCircuit\(_{HIIT}\)) daily for 4 weeks. In this single-center, two-arm randomized, controlled study, 24 men and women (age: 25 ± 5 years) first received no training instructions for 4 weeks and then performed 4 weeks of either 1xCircuitHIIT or 2xCircuit\(_{HIIT}\) (5 men and 7 women in each group) daily. The 1xCircuitHIIT and 2xCircuit\(_{HIIT}\) participants carried out 90.7 and 85.7% of all planned training sessions, respectively, with average heart rates during the 6-min sessions of 74.3 and 70.8% of maximal heart rate. Body, fat and fat-free mass, and metabolic rate at rest did not differ between the groups or between time-points of measurement. Heart rate while running at 6 km⋅h\(^{-1}\) declined after the intervention in both groups. Submaximal and peak oxygen uptake, the respiratory exchange ratio and heart rate recovery were not altered by either intervention. The maximal numbers of push-ups, leg-levers, burpees, 45°-one-legged squats and 30-s skipping, as well as perception of general health improved in both groups. Our 1xCircuit\(_{HIIT}\) or 2xCircuit\(_{HIIT}\) interventions improved certain parameters of functional strength and certain dimensions of quality of life in young untrained individuals. However, they were not sufficient to enhance cardio-respiratory fitness, in particular peak oxygen uptake. KW - aerobic fitness KW - body composition KW - functional training KW - mHealth KW - power training KW - V800 KW - wearable KW - web-based apps Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-176565 VL - 9 IS - 423 ER - TY - JOUR A1 - Biscotti, Maria Assunta A1 - Adolfi, Mateus Contar A1 - Barucca, Marco A1 - Forconi, Mariko A1 - Pallavicini, Alberto A1 - Gerdol, Marco A1 - Canapa, Adriana A1 - Schartl, Manfred T1 - A comparative view on sex differentiation and gametogenesis genes in lungfish and coelacanths JF - Genome Biology and Evolution N2 - Gonadal sex differentiation and reproduction are the keys to the perpetuation of favorable gene combinations and positively selected traits. In vertebrates, several gonad development features that differentiate tetrapods and fishes are likely to be, at least in part, related to the water-to-land transition. The collection of information from basal sarcopterygians, coelacanths, and lungfishes, is crucial to improve our understanding of the molecular evolution of pathways involved in reproductive functions, since these organisms are generally regarded as “living fossils” and as the direct ancestors of tetrapods. Here, we report for the first time the characterization of >50 genes related to sex differentiation and gametogenesis in Latimeria menadoensis and Protopterus annectens. Although the expression profiles of most genes is consistent with the intermediate position of basal sarcopterygians between actinopterygian fish and tetrapods, their phylogenetic placement and presence/absence patterns often reveal a closer affinity to the tetrapod orthologs. On the other hand, particular genes, for example, the male gonad factor gsdf (Gonadal Soma-Derived Factor), provide examples of ancestral traits shared with actinopterygians, which disappeared in the tetrapod lineage. KW - sex differentiation KW - Latimeria menadoensis KW - Protopterus annectens KW - evolution KW - testis KW - gametogenesis KW - ovary Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-176774 VL - 10 IS - 6 ER - TY - JOUR A1 - Pauls, Dennis A1 - Blechschmidt, Christine A1 - Frantzmann, Felix A1 - el Jundi, Basil A1 - Selcho, Mareike T1 - A comprehensive anatomical map of the peripheral octopaminergic/tyraminergic system of Drosophila melanogaster JF - Scientific Reports N2 - The modulation of an animal’s behavior through external sensory stimuli, previous experience and its internal state is crucial to survive in a constantly changing environment. In most insects, octopamine (OA) and its precursor tyramine (TA) modulate a variety of physiological processes and behaviors by shifting the organism from a relaxed or dormant condition to a responsive, excited and alerted state. Even though OA/TA neurons of the central brain are described on single cell level in Drosophila melanogaster, the periphery was largely omitted from anatomical studies. Given that OA/TA is involved in behaviors like feeding, flying and locomotion, which highly depend on a variety of peripheral organs, it is necessary to study the peripheral connections of these neurons to get a complete picture of the OA/TA circuitry. We here describe the anatomy of this aminergic system in relation to peripheral tissues of the entire fly. OA/TA neurons arborize onto skeletal muscles all over the body and innervate reproductive organs, the heart, the corpora allata, and sensory organs in the antennae, legs, wings and halteres underlining their relevance in modulating complex behaviors. KW - neural circuits KW - peripheral nervous system KW - Drosophila melanogaster Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-177412 VL - 8 IS - 15314 ER - TY - THES A1 - Gründler, Klaus T1 - A Contribution to the Empirics of Economic Development - The Role of Technology, Inequality, and the State T1 - Eine empirische Untersuchung der wirtschaftlichen Entwicklung - Die Rolle von Technologien, Ungleichheit und dem Staat N2 - This dissertation contributes to the empirical analysis of economic development. The continuing poverty in many Sub-Saharan-African countries as well as the declining trend in growth in the advanced economies that was initiated around the turn of the millennium raises a number of new questions which have received little attention in recent empirical studies. Is culture a decisive factor for economic development? Do larger financial markets trigger positive stimuli with regard to incomes, or is the recent increase in their size in advanced economies detrimental to economic growth? What causes secular stagnation, i.e. the reduction in growth rates of the advanced economies observable over the past 20 years? What is the role of inequality in the growth process, and how do governmental attempts to equalize the income distribution affect economic development? And finally: Is the process of democratization accompanied by an increase in living standards? These are the central questions of this doctoral thesis. To facilitate the empirical analysis of the determinants of economic growth, this dissertation introduces a new method to compute classifications in the field of social sciences. The approach is based on mathematical algorithms of machine learning and pattern recognition. Whereas the construction of indices typically relies on arbitrary assumptions regarding the aggregation strategy of the underlying attributes, utilization of Support Vector Machines transfers the question of how to aggregate the individual components into a non-linear optimization problem. Following a brief overview of the theoretical models of economic growth provided in the first chapter, the second chapter illustrates the importance of culture in explaining the differences in incomes across the globe. In particular, if inhabitants have a lower average degree of risk-aversion, the implementation of new technology proceeds much faster compared with countries with a lower tendency towards risk. However, this effect depends on the legal and political framework of the countries, their average level of education, and their stage of development. The initial wealth of individuals is often not sufficient to cover the cost of investments in both education and new technologies. By providing loans, a developed financial sector may help to overcome this shortage. However, the investigations in the third chapter show that this mechanism is dependent on the development levels of the economies. In poor countries, growth of the financial sector leads to better education and higher investment levels. This effect diminishes along the development process, as intermediary activity is increasingly replaced by speculative transactions. Particularly in times of low technological innovation, an increasing financial sector has a negative impact on economic development. In fact, the world economy is currently in a phase of this kind. Since the turn of the millennium, growth rates in the advanced economies have experienced a multi-national decline, leading to an intense debate about "secular stagnation" initiated at the beginning of 2015. The fourth chapter deals with this phenomenon and shows that the growth potentials of new technologies have been gradually declining since the beginning of the 2000s. If incomes are unequally distributed, some individuals can invest less in education and technological innovations, which is why the fifth chapter identifies an overall negative effect of inequality on growth. This influence, however, depends on the development level of countries. While the negative effect is strongly pronounced in poor economies with a low degree of equality of opportunity, this influence disappears during the development process. Accordingly, redistributive polices of governments exert a growth-promoting effect in developing countries, while in advanced economies, the fostering of equal opportunities is much more decisive. The sixth chapter analyzes the growth effect of the political environment and shows that the ambiguity of earlier studies is mainly due to unsophisticated measurement of the degree of democratization. To solve this problem, the chapter introduces a new method based on mathematical algorithms of machine learning and pattern recognition. While the approach can be used for various classification problems in the field of social sciences, in this dissertation it is applied for the problem of democracy measurement. Based on different country examples, the chapter shows that the resulting SVMDI is superior to other indices in modeling the level of democracy. The subsequent empirical analysis emphasizes a significantly positive growth effect of democracy measured via SVMDI. N2 - Die Dissertation beschäftigt sich mit der statistischen und empirischen Analyse der Determinanten langfristiger Wachstumsprozesse. Die anhaltende Armut vieler Staaten in Subsahara-Afrika sowie die rückläufigen Wachstumsraten der reichen Volkswirtschaften seit Beginn des neuen Jahrtausends werfen eine Reihe neuer Fragen auf, die bislang wenig empirisch erforscht sind. Ist die Kultur eines Landes entscheidend für die Entwicklung der Wohlfahrt? Kann ein entwickelter Finanzsektor Wohlstandssteigerungen auslösen, oder ist der starke Zuwachs der Finanzmärkte, der in den Industrienationen beobachtet werden kann, schädlich für die Entwicklung? Warum wachsen reiche Volkswirtschaften heute so viel langsamer als noch vor 20 Jahren? Welchen Einfluss nimmt die zunehmende Einkommensungleichheit auf die wirtschaftliche Entwicklung und welchen Effekt haben staatliche Umverteilungsmaßnahmen? Und schließlich: Führen stärkere politische Rechte und mehr Demokratie zu einer Zunahme der Lebensstandards? Dies sind die zentralen Fragestellungen, denen sich die Kapitel dieser Doktorarbeit widmen. Um die Analyse der empirischen Ursachen der wirtschaftlichen Entwicklung zu erleichtern, leitet die Dissertation überdies ein neues Verfahren zur Lösung von Klassifikationsproblemen in den Sozialwissenschaften ab. Das Verfahren beruht auf mathematischen Algorithmen zur Mustererkennung und des maschinellen Lernens. Dies bietet neue Möglichkeiten für das Konstruieren von Indizes, die zumeist auf arbiträre Annahmen über die zugrundeliegende Aggregationsfunktion zurückgreifen. Das vorgestellte Verfahren löst dieses Problem, in dem die Aggregation durch Support Vector Machines in ein nicht-lineares Optimierungsproblem überführt wird. Nach einem kurzen Überblick über die theoretischen Erklärungsansätze der wirtschaftlichen Entwicklung im ersten Kapitel zeigt das zweite Kapitel, dass kulturelle Unterschieden einen Einfluss auf die ökonomische Entwicklung ausüben. Die Ergebnisse implizieren, dass Länder mit einer geringeren Aversion gegen Risiken höhere Wachstumsraten aufweisen, da in diesen Ländern die Implementierung neuer Technologien schneller voranschreitet. Der Effekt ist allerdings abhängig von den rechtlichen und politischen Rahmenbedingungen der Länder, vom durchschnittlichen Bildungsniveau sowie vom Entwicklungsstand. In vielen Fällen reichen die Vermögen der Individuen nicht aus, um Investitionen in Bildung, Kapital und neue Technologien zu stemmen. Durch die Bereitstellung von Krediten kann ein entwickelter Finanzsektor diesen Engpass überwinden. Die Untersuchungen des dritten Kapitels zeigen allerdings, dass dieser Mechanismus abhängig ist von den Entwicklungsniveaus der Volkswirtschaften. In armen Ländern führt ein Anstieg des Finanzsektors zu besserer Bildung und höheren Investitionen. Dieser Effekt nimmt jedoch über den Entwicklungsprozess ab, da die Intermediationstätigkeit zunehmend durch spekulative Geschäfte ersetzt wird. Insbesondere in Zeiten mit geringen technologischen Neuerungen wirkt ein wachsender Finanzsektor negativ auf die ökonomische Entwicklung. Aktuell befindet sich die Weltökonomie in einer solchen Phase, was verbunden mit einem multinationalen Rückgang der Wachstumsraten seit Anfang 2015 als "säkulare Stagnation" diskutiert wird. Das vierte Kapitel befasst sich intensiv mit diesem Phänomen und zeigt, dass die gegenwärtigen Wachstumspotenziale neuer Technologien seit Beginn der 2000er Jahre zunehmend auslaufen. Sind die Einkommen ungleich verteilt, so können einige Individuen weniger Investitionen in Bildung und technologische Neuerungen durchführen. Tatsächlich weist das fünfte Kapitel auf einen insgesamt negativen Effekt der Ungleichheit auf das Wachstum hin. Dieser Einfluss ist allerdings abhängig vom Entwicklungsstand der Länder. Während der negative Effekt in armen Volkswirtschaften mit einem geringen Maß an Chancengleichheit stark ausgeprägt ist, verschwindet dieser Einfluss mit zunehmendem Entwicklungsniveau. Entsprechend wirkt direkte staatliche Umverteilung vor allem in unterentwickelten Ländern wachstumsfördernd. In entwickelten Nationen ist hingegen die Schaffung von Chancengleichheit entscheidend. Das sechste Kapitel analysiert den Wachstumseffekt des politischen Umfelds und zeigt, dass die Ambivalenz früherer Studien auf die mangelhafte Abbildung des Demokratiegrades zurückzuführen ist. Zur Lösung dieses Problems wird ein neues Verfahren vorgeschlagen, das auf mathematischen Algorithmen des maschinellen Lernens basiert. Das Verfahren kann in verschiedenen Bereichen der Sozialwissenschaften eingesetzt werden und wird in der Arbeit zur Klassifikation des Demokratiegrades angewandt. Auf Basis verschiedener Länderbeispiele wird deutlich, dass der resultierende SVMDI anderen Indizes in der Modellierung des Demokratiegrades überlegen ist. Die anschließende empirische Analyse betont einen signifikant positiven Effekt des SVMDI auf das Wirtschaftswachstum. N2 - Why are some nations rich and others poor? What are the sources of long-run economic development and growth? How can living standards be increased? In this book, Klaus Gründler empirically analyses these central economic questions and puts a particular emphasis on the role of technology, inequality, and political institutions. To substantiate his empirical studies, he introduces a new method to compute composite measures and indices that is based on mathematical algorithms from the field of machine learning. KW - Wirtschaftsentwicklung KW - Wirtschaftsstruktur KW - Sozioökonomisches System KW - Inequality KW - Economic Growth KW - Machine Learning KW - Empirical Economics KW - Ungleichheit KW - Wirtschaftswachstum KW - Maschinelles Lernen KW - Makroökonomie KW - Empirische Wirtschaftsforschung Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-141520 SN - 978-3-95826-072-6 (Print) SN - 978-3-95826-073-3 (Online) N1 - Parallel erschienen als Druckausgabe in Würzburg University Press, 978-3-95826-072-6, 41,80 EUR. PB - Würzburg University Press CY - Würzburg ET - 1. Auflage ER - TY - JOUR A1 - Langhauser, Friederike A1 - Casas, Ana I. A1 - Dao, Vu-Thao-Vi A1 - Guney, Emre A1 - Menche, Jörg A1 - Geuss, Eva A1 - Kleikers, Pamela W. M. A1 - López, Manuela G. A1 - Barabási, Albert-L. A1 - Kleinschnitz, Christoph A1 - Schmidt, Harald H. H. W. T1 - A diseasome cluster-based drug repurposing of soluble guanylate cyclase activators from smooth muscle relaxation to direct neuroprotection JF - npj Systems Biology and Applications N2 - Network medicine utilizes common genetic origins, markers and co-morbidities to uncover mechanistic links between diseases. These links can be summarized in the diseasome, a comprehensive network of disease–disease relationships and clusters. The diseasome has been influential during the past decade, although most of its links are not followed up experimentally. Here, we investigate a high prevalence unmet medical need cluster of disease phenotypes linked to cyclic GMP. Hitherto, the central cGMP-forming enzyme, soluble guanylate cyclase (sGC), has been targeted pharmacologically exclusively for smooth muscle modulation in cardiology and pulmonology. Here, we examine the disease associations of sGC in a non-hypothesis based manner in order to identify possibly previously unrecognized clinical indications. Surprisingly, we find that sGC, is closest linked to neurological disorders, an application that has so far not been explored clinically. Indeed, when investigating the neurological indication of this cluster with the highest unmet medical need, ischemic stroke, pre-clinically we find that sGC activity is virtually absent post-stroke. Conversely, a heme-free form of sGC, apo-sGC, was now the predominant isoform suggesting it may be a mechanism-based target in stroke. Indeed, this repurposing hypothesis could be validated experimentally in vivo as specific activators of apo-sGC were directly neuroprotective, reduced infarct size and increased survival. Thus, common mechanism clusters of the diseasome allow direct drug repurposing across previously unrelated disease phenotypes redefining them in a mechanism-based manner. Specifically, our example of repurposing apo-sGC activators for ischemic stroke should be urgently validated clinically as a possible first-in-class neuroprotective therapy. KW - neurology KW - pharmacology KW - systems biology Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-236381 VL - 4 ER - TY - JOUR A1 - Hommers, L. G. A1 - Richter, J. A1 - Yang, Y. A1 - Raab, A. A1 - Baumann, C. A1 - Lang, K. A1 - Schiele, M. A. A1 - Weber, H. A1 - Wittmann, A. A1 - Wolf, C. A1 - Alpers, G. W. A1 - Arolt, V. A1 - Domschke, K. A1 - Fehm, L. A1 - Fydrich, T. A1 - Gerlach, A. A1 - Gloster, A. T. A1 - Hamm, A. O. A1 - Helbig-Lang, S. A1 - Kircher, T. A1 - Lang, T. A1 - Pané-Farré, C. A. A1 - Pauli, P. A1 - Pfleiderer, B. A1 - Reif, A. A1 - Romanos, M. A1 - Straube, B. A1 - Ströhle, A. A1 - Wittchen, H.-U. A1 - Frantz, S. A1 - Ertl, G. A1 - Lohse, M. J. A1 - Lueken, U. A1 - Deckert, J. T1 - A functional genetic variation of SLC6A2 repressor hsa-miR-579-3p upregulates sympathetic noradrenergic processes of fear and anxiety JF - Translational Psychiatry N2 - Increased sympathetic noradrenergic signaling is crucially involved in fear and anxiety as defensive states. MicroRNAs regulate dynamic gene expression during synaptic plasticity and genetic variation of microRNAs modulating noradrenaline transporter gene (SLC6A2) expression may thus lead to altered central and peripheral processing of fear and anxiety. In silico prediction of microRNA regulation of SLC6A2 was confirmed by luciferase reporter assays and identified hsa-miR-579-3p as a regulating microRNA. The minor (T)-allele of rs2910931 (MAFcases = 0.431, MAFcontrols = 0.368) upstream of MIR579 was associated with panic disorder in patients (pallelic = 0.004, ncases = 506, ncontrols = 506) and with higher trait anxiety in healthy individuals (pASI = 0.029, pACQ = 0.047, n = 3112). Compared to the major (A)-allele, increased promoter activity was observed in luciferase reporter assays in vitro suggesting more effective MIR579 expression and SLC6A2 repression in vivo (p = 0.041). Healthy individuals carrying at least one (T)-allele showed a brain activation pattern suggesting increased defensive responding and sympathetic noradrenergic activation in midbrain and limbic areas during the extinction of conditioned fear. Panic disorder patients carrying two (T)-alleles showed elevated heart rates in an anxiety-provoking behavioral avoidance test (F(2, 270) = 5.47, p = 0.005). Fine-tuning of noradrenaline homeostasis by a MIR579 genetic variation modulated central and peripheral sympathetic noradrenergic activation during fear processing and anxiety. This study opens new perspectives on the role of microRNAs in the etiopathogenesis of anxiety disorders, particularly their cardiovascular symptoms and comorbidities. KW - clinical genetics KW - psychiatric disorders Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-322497 VL - 8 ER - TY - JOUR A1 - Bar-Yosef, Hagit A1 - Gildor, Tsvia A1 - Ramírez-Zavala, Bernardo A1 - Schmauch, Christian A1 - Weissman, Ziva A1 - Pinsky, Mariel A1 - Naddaf, Rawi A1 - Morschhäuser, Joachim A1 - Arkowitz, Robert A. A1 - Kornitzer, Daniel T1 - A global analysis of kinase function in Candida albicans hyphal morphogenesis reveals a role for the endocytosis regulator Akl1 JF - Frontiers in Cellular and Infection Microbiology N2 - The human pathogenic fungus Candida albicans can switch between yeast and hyphal morphologies as a function of environmental conditions and cellular physiology. The yeast-to-hyphae morphogenetic switch is activated by well-established, kinase-based signal transduction pathways that are induced by extracellular stimuli. In order to identify possible inhibitory pathways of the yeast-to-hyphae transition, we interrogated a collection of C. albicans protein kinases and phosphatases ectopically expressed under the regulation of the TETon promoter. Proportionately more phosphatases than kinases were identified that inhibited hyphal morphogenesis, consistent with the known role of protein phosphorylation in hyphal induction. Among the kinases, we identified AKL1 as a gene that significantly suppressed hyphal morphogenesis in serum. Akl1 specifically affected hyphal elongation rather than initiation: overexpression of AKL1 repressed hyphal growth, and deletion of AKL1 resulted in acceleration of the rate of hyphal elongation. Akl1 suppressed fluid-phase endocytosis, probably via Pan1, a putative clathrin-mediated endocytosis scaffolding protein. In the absence of Akl1, the Pan1 patches were delocalized from the sub-apical region, and fluid-phase endocytosis was intensified. These results underscore the requirement of an active endocytic pathway for hyphal morphogenesis. Furthermore, these results suggest that under standard conditions, endocytosis is rate-limiting for hyphal elongation. KW - hyphae KW - endocytosis KW - Pan1 KW - functional genomics Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-197204 SN - 2235-2988 VL - 8 ER - TY - JOUR A1 - Carradec, Quentin A1 - Pelletier, Eric A1 - Da Silva, Corinne A1 - Alberti, Adriana A1 - Seeleuthner, Yoann A1 - Blanc-Mathieu, Romain A1 - Lima-Mendez, Gipsi A1 - Rocha, Fabio A1 - Tirichine, Leila A1 - Labadie, Karine A1 - Kirilovsky, Amos A1 - Bertrand, Alexis A1 - Engelen, Stefan A1 - Madoui, Mohammed-Amin A1 - Méheust, Raphaël A1 - Poulain, Julie A1 - Romac, Sarah A1 - Richter, Daniel J. A1 - Yoshikawa, Genki A1 - Dimier, Céline A1 - Kandels-Lewis, Stefanie A1 - Picheral, Marc A1 - Searson, Sarah A1 - Jaillon, Olivier A1 - Aury, Jean-Marc A1 - Karsenti, Eric A1 - Sullivan, Matthew B. A1 - Sunagawa, Shinichi A1 - Bork, Peer A1 - Not, Fabrice A1 - Hingamp, Pascal A1 - Raes, Jeroen A1 - Guidi, Lionel A1 - Ogata, Hiroyuki A1 - de Vargas, Colomban A1 - Iudicone, Daniele A1 - Bowler, Chris A1 - Wincker, Patrick T1 - A global ocean atlas of eukaryotic gene JF - Nature Communications N2 - While our knowledge about the roles of microbes and viruses in the ocean has increased tremendously due to recent advances in genomics and metagenomics, research on marine microbial eukaryotes and zooplankton has benefited much less from these new technologies because of their larger genomes, their enormous diversity, and largely unexplored physiologies. Here, we use a metatranscriptomics approach to capture expressed genes in open ocean Tara Oceans stations across four organismal size fractions. The individual sequence reads cluster into 116 million unigenes representing the largest reference collection of eukaryotic transcripts from any single biome. The catalog is used to unveil functions expressed by eukaryotic marine plankton, and to assess their functional biogeography. Almost half of the sequences have no similarity with known proteins, and a great number belong to new gene families with a restricted distribution in the ocean. Overall, the resource provides the foundations for exploring the roles of marine eukaryotes in ocean ecology and biogeochemistry. KW - genomics KW - marine biology KW - microbial ecology KW - water microbiology Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-222250 VL - 9 ER - TY - JOUR A1 - Semler, Elisa A1 - Anderl-Straub, Sarah A1 - Uttner, Ingo A1 - Diehl-Schmid, Janine A1 - Danek, Adrian A1 - Einsiedler, Beate A1 - Fassbender, Klaus A1 - Fliessbach, Klaus A1 - Huppertz, Hans-Jürgen A1 - Jahn, Holger A1 - Kornhuber, Johannes A1 - Landwehrmeyer, Bernhard A1 - Lauer, Martin A1 - Muche, Rainer A1 - Prudlo, Johannes A1 - Schneider, Anja A1 - Schroeter, Matthias L. A1 - Ludolph, Albert C. A1 - Otto, Markus T1 - A language-based sum score for the course and therapeutic intervention in primary progressive aphasia JF - Alzheimer's Research & Therapy N2 - Background With upcoming therapeutic interventions for patients with primary progressive aphasia (PPA), instruments for the follow-up of patients are needed to describe disease progression and to evaluate potential therapeutic effects. So far, volumetric brain changes have been proposed as clinical endpoints in the literature, but cognitive scores are still lacking. This study followed disease progression predominantly in language-based performance within 1 year and defined a PPA sum score which can be used in therapeutic interventions. Methods We assessed 28 patients with nonfluent variant PPA, 17 with semantic variant PPA, 13 with logopenic variant PPA, and 28 healthy controls in detail for 1 year. The most informative neuropsychological assessments were combined to a sum score, and associations between brain atrophy were investigated followed by a sample size calculation for clinical trials. Results Significant absolute changes up to 20% in cognitive tests were found after 1 year. Semantic and phonemic word fluency, Boston Naming Test, Digit Span, Token Test, AAT Written language, and Cookie Test were identified as the best markers for disease progression. These tasks provide the basis of a new PPA sum score. Assuming a therapeutic effect of 50% reduction in cognitive decline for sample size calculations, a number of 56 cases is needed to find a significant treatment effect. Correlations between cognitive decline and atrophy showed a correlation up to r = 0.7 between the sum score and frontal structures, namely the superior and inferior frontal gyrus, as well as with left-sided subcortical structures. Conclusion Our findings support the high performance of the proposed sum score in the follow-up of PPA and recommend it as an outcome measure in intervention studies. KW - frontotemporal dementia KW - cognitive neuropsychology in dementia KW - assessment of cognitive disorders/dementia KW - volumetric MRI KW - aphasia Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-236277 VL - 10 ER - TY - INPR A1 - Höbartner, Claudia A1 - Steinmetzger, Christian A1 - Palanisamy, Navaneethan A1 - Gore, Kiran R. T1 - A multicolor large Stokes shift fluorogen-activating RNA aptamer with cationic chromophores T2 - Chemistry - A European Journal N2 - Large Stokes shift (LSS) fluorescent proteins (FPs) exploit excited state proton transfer pathways to enable fluorescence emission from the phenolate intermediate of their internal 4 hydroxybenzylidene imidazolone (HBI) chromophore. An RNA aptamer named Chili mimics LSS FPs by inducing highly Stokes-shifted emission from several new green and red HBI analogs that are non-fluorescent when free in solution. The ligands are bound by the RNA in their protonated phenol form and feature a cationic aromatic side chain for increased RNA affinity and reduced magnesium dependence. In combination with oxidative functional-ization at the C2 position of the imidazolone, this strategy yielded DMHBO\(^+\), which binds to the Chili aptamer with a low-nanomolar K\(_D\). Because of its highly red-shifted fluorescence emission at 592 nm, the Chili–DMHBO\(^+\) complex is an ideal fluorescence donor for Förster resonance energy transfer (FRET) to the rhodamine dye Atto 590 and will therefore find applications in FRET-based analytical RNA systems. KW - RNA Aptamer KW - fluorescence KW - large Stokes shift KW - fluorescent protein KW - fluorescent resonance energy transfer Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-174197 N1 - This is the pre-peer reviewed version of the following article: Steinmetzger, C. , Palanisamy, N. , Gore, K. . and Höbartner, C. (2018), A multicolor large Stokes shift fluorogen‐activating RNA aptamer with cationic chromophores. Chem. Eur. J. doi:10.1002/chem.201805882, which has been published in final form at https://doi.org/10.1002/chem.201805882. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions. ER - TY - JOUR A1 - Balasubramanian, Srikkanth A1 - Skaf, Joseph A1 - Holzgrabe, Ulrike A1 - Bharti, Richa A1 - Förstner, Konrad U. A1 - Ziebuhr, Wilma A1 - Humeida, Ute H. A1 - Abdelmohsen, Usama R. A1 - Oelschlaeger, Tobias A. T1 - A new bioactive compound from the marine sponge-derived Streptomyces sp. SBT348 inhibits staphylococcal growth and biofilm formation JF - Frontiers in Microbiology N2 - Staphylococcus epidermidis, the common inhabitant of human skin and mucosal surfaces has emerged as an important pathogen in patients carrying surgical implants and medical devices. Entering the body via surgical sites and colonizing the medical devices through formation of multi-layered biofilms leads to refractory and persistent device-related infections (DRIs). Staphylococci organized in biofilms are more tolerant to antibiotics and immune responses, and thus are difficult-to-treat. The consequent morbidity and mortality, and economic losses in health care systems has strongly necessitated the need for development of new anti-bacterial and anti-biofilm-based therapeutics. In this study, we describe the biological activity of a marine sponge-derived Streptomyces sp. SBT348 extract in restraining staphylococcal growth and biofilm formation on polystyrene, glass, medically relevant titan metal, and silicone surfaces. A bioassay-guided fractionation was performed to isolate the active compound (SKC3) from the crude SBT348 extract. Our results demonstrated that SKC3 effectively inhibits the growth (MIC: 31.25 \(\mu\)g/ml) and biofilm formation (sub-MIC range: 1.95-<31.25 \(\mu\)g/ml) of S. epidermidis RP62A in vitro. Chemical characterization of SKC3 by heat and enzyme treatments, and mass spectrometry (HRMS) revealed its heat-stable and non-proteinaceous nature, and high molecular weight (1258.3 Da). Cytotoxicity profiling of SKC3 in vitro on mouse fibroblast (NIH/3T3) and macrophage (J774.1) cell lines, and in vivo on the greater wax moth larvae Galleria mellonella revealed its non-toxic nature at the effective dose. Transcriptome analysis of SKC3 treated S. epidermidis RP62A has further unmasked its negative effect on central metabolism such as carbon flux as well as, amino acid, lipid, and energy metabolism. Taken together, these findings suggest a potential of SKC3 as a putative drug to prevent staphylococcal DRIs. KW - marine sponges KW - Streptomyces KW - Staphylococci KW - device-related infections KW - bioassay-guided fractionation KW - transcriptome Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-221408 VL - 9 ER - TY - THES A1 - Godbole, Amod Anand T1 - A new paradigm in GPCR signaling at the trans-Golgi network of thyroid cells T1 - Ein neues Model der GPCR Signaltransduktion am trans-Golgi-Netzwerk von Schilddrüsenzellen N2 - Whereas G-protein coupled receptors (GPCRs) have been long believed to signal through cyclic AMP exclusively at cell surface, our group has previously shown that GPCRs not only signal at the cell surface but can also continue doing so once internalized together with their ligands, leading to persistent cAMP production. This phenomenon, which we originally described for the thyroid stimulating hormone receptor (TSHR) in thyroid cells, has been observed also for other GPCRs. However, the intracellular compartment(s) responsible for such persistent signaling and its consequences on downstream effectors were insufficiently characterized. The aim of this study was to follow by live-cell imaging the trafficking of internalized TSHRs and other involved signaling proteins as well as to understand the consequences of signaling by internalized TSHRs on the downstream activation of protein kinase A (PKA). cAMP and PKA activity was measured in real-time in living thyroid cells using FRET-based sensors Epac1-camp and AKAR2 respectively. The results suggest that TSH co-internalizes with its receptor and that the internalized TSH/TSHR complexes traffic retrogradely to the trans-Golgi network (TGN). This study also provides evidence that these internalized TSH/TSHR complexes meet an intracellular pool of Gs proteins in sorting endosomes and in TGN and activate it there, as visualized in real-time using a conformational biosensor nanobody, Nb37. Acute Brefeldin A-induced Golgi collapse hinders the retrograde trafficking of TSH/TSHR complexes, leading to reduced cAMP production and PKA signaling. BFA pretreatment was also able to attenuate CREB phosphorylation suggesting that an intact Golgi/TGN organisation is essential for an efficient cAMP/PKA signaling by internalized TSH/TSHR complexes. Taken together this data provides evidence that internalized TSH/TSHR complexes meet and activate Gs proteins in sorting endosomes and at the TGN, leading to a local activation of PKA and consequently increased CREB activation. These findings suggest unexpected functions for receptor internalization, with major pathophysiological and pharmacological implications. N2 - G-Protein-gekoppelte Rezeptoren sind nur in Eukaryonten vorhandeln und bilden die größte und diverseste Familie von Zellmembranrezeptoren. Sie reagieren auf eine vielfältige Gruppe von Stimuli die verschiedene Effektoren aktivieren und damit nachgelagerte Signalkaskaden auslösen, die letztlich entscheidend für die Zellphysiologie sind. Die Regelung der Ligand-vermittelten Signaltransduktion wird hauptsächlich durch die Desensibilisierung des GPCR mittels Dephosphorylierung (katalysiert durch GRK) und zusätzlich durch Internalisierung des GPCR gesteuert. Die Annahme, dass GPCRs für cAMP nur an der Zellmembran signalisieren und nicht mehr sobald sie in die Zelle internalisiert wurden, konnte durch wegweisende unabhängige Forschung an GPCRs im Besonderen an TSHR und PTHR geändert werden. So konnte gezeigt werden, dass sie für cAMP nicht nur an der Zellmembran signalisieren, sondern auch, wenn sie in intrazelluläre Zellkompartimente internalisiert wurde. Dieses Phänomen („sustained signaling“ hier „anhaltende Signalisierung“) wurde seitdem für andere GPCRs (z.B. 2-AR, V2R und LHR) beschrieben. Aber die Zellkompartimente wurden für nachhaltige intrazelluläre Signale nicht ausreichend charakterisiert. Das Ziel dieser Arbeit war es die Bewegung und die dynamische Natur der möglichen signalisierenden Kompartimente mittels „real-time TIRF“-Mikroskopie und die Signalisierung unter Verwendung von „real-time FRET“ in primären Maus Schilddrüsenzellen zu untersuchen. Die vorliegende Arbeit berichtet, dass TSH/TSHR Komplexe internalisieren und ein signifikanter Teil, welcher vom Retromer Komplex angeführt wird, gelangt über den retrograden (rückwärts gerichteten) Transport in das trans-Golgi-Netzwerk (TGN). Diese TSH/TSHR-Komplexe treffen nicht in den frühen Endosomen auf die Gs-Proteine, sondern in den „Sortierer Endosomen“ und in dem TGN. Ein direkter Beweis für Gs Protein Aktivierung und Signaltransduktion am TGN und in Sortierer Endosomen konnte mittels des nanobody Nb37, einem spezifischen Biosensor für das aktive Gs Protein, erbracht werden. Es konnte gezeigt werden, dass die Sequestrierung von Nb37 an diesen Kompartimenten ein szintillierendes Verhalten in Zeit und Raum zeigt. Die vorliegende Arbeit zeigt, dass die katalytische Untereinheit der PKA am Golgi/TGN angereichert ist. Die Behandlung mit Brefeldin A führt zum Verlust dieser PKA Lokalisation am Golgi. Die Beschädigung und Reorganisation des TGN durch Brefeldin A führt zu a) einer abgeschwächten cAMP Reaktion b) einer dreiphasigen PKA Reaktion charakterisiert durch eine schnelle erste Phase, eine langsame (deutlich abgeschwächte) zweite Phase und eine verzögerte dritte Phase und schließlich c) einer abgeschwächte CREB Phosphorylierung. Es gibt Anzeichen dafür, dass die Reorganisation des TGN Kompartimente betrifft, die verantwortlich für intrazelluläre cAMP- und PKA-Signalisierung sind. Zusammenfassend lässt sich sagen, dass das TGN eines der Kompartimente ist, das für die anhaltende TSHR-Signalisierung verantwortlich ist. KW - G-Protein gekoppelte Rezeptoren KW - GPCR KW - thyroid stimulating hormone receptor KW - trans-Golgi network KW - Signaltransduktion KW - Golgi-Apparat KW - Schilddrüse Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-147159 ER - TY - JOUR A1 - Reichert, Johannes C. A1 - von Rottkay, Eberhard A1 - Roth, Franz A1 - Renz, Tim A1 - Hausmann, Johannes A1 - Kranz, Julius A1 - Rackwitz, Lars A1 - Nöth, Ulrich A1 - Rudert, Maximilian T1 - A prospective randomized comparison of the minimally invasive direct anterior and the transgluteal approach for primary total hip arthroplasty JF - BMC Musculoskeletal Disorders N2 - Background: The presented prospective randomized controlled single-centre study compares the clinical outcome up to 12 months after total hip arthroplasty using a minimally invasive single-incision direct anterior (DAA) and a direct transgluteal lateral approach. Methods: A total of 123 arthroplasties were evaluated utilizing the Harris Hip Score (HHS), the extra short musculoskeletal functional assessment questionnaire (XSFMA), the Short Form 36 (SF-36) health survey, a Stepwatch™ Activity Monitor (SAM), and a timed 25 m foot walk (T25-FW). Postoperative x-ray images after THA were reviewed to determine inclination and stem positioning. Results: At final follow-up, the XSFMA functional index scores were 10.3 (anterior) and 15.08 (lateral) while the bother index summed up to a score of 15.8 (anterior) and 21.66 (lateral) respectively, thus only differing significantly for the functional index (p = 0.040 and p = 0.056). The SF-36 physical component score (PCS) was 47.49 (anterior) and 42.91 (lateral) while the mental component score (MCS) summed up to 55.0 (anterior) and 56.23 (lateral) with a significant difference evident for the PCS (p = 0.017; p = 0.714). Patients undergoing THA through a DAA undertook a mean of 6402 cycles per day while those who had undergone THA through a transgluteal approach undertook a mean of 5340 cycles per day (p = 0.012). Furthermore, the obtained outcome for the T25-FW with 18.4 s (anterior) and 19.75 s (lateral) and the maximum walking distance (5932 m and 5125 m) differed significantly (p = 0.046 and p = 0.045). The average HHS showed no significant difference equaling 92.4 points in the anterior group and 91.43 in the lateral group (p = 0.477). The radiographic analysis revealed an average cup inclination of 38.6° (anterior) and 40.28° (lateral) without signs of migration. Conclusion: In summary, our outcomes show that after 1 year THA through the direct anterior approach results in a higher patient activity compared to THA utilizing a transgluteal lateral approach while no differences regarding hip function are evident. KW - total hip arthroplasty KW - direct anterior approach KW - minimally invasive KW - transgluteal approach KW - prospective study Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-176072 VL - 19 IS - 241 ER - TY - JOUR T1 - A search for pair-produced resonances in four-jet final states at root s=13 TeV with the ATLAS detector JF - The European Physical Journal C N2 - A search for massive coloured resonances which are pair-produced and decay into two jets is presented. The analysis uses 36.7 fb(-1) of root s = 13 TeV pp collision data recorded by the ATLAS experiment at the LHC in 2015 and 2016. No significant deviation from the background prediction is observed. Results are interpreted in a SUSY simplified model where the lightest supersymmetric particle is the top squark, (t) over tilde, which decays promptly into two quarks through R-parity-violating couplings. Top squarks with masses in the range 100 GeV < m((T) over tilde) < 410 GeV are excluded at 95% confidence level. If the decay is into a b-quark and a light quark, a dedicated selection requiring two b-tags is used to exclude masses in the ranges 100 GeV < m((t) over tilde) < 470 GeV and 480 GeV < m(<(t)over tilde>) < 610 GeV. Additional limits are set on the pair-production of massive colour-octet resonances. KW - Patron Distributions KW - Collicions KW - Extension KW - Squark KW - Supersymmetry KW - Color KW - Decay Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-225465 VL - 78 IS - 250 ER - TY - JOUR T1 - A search for resonances decaying into a Higgs boson and a new particle \(X\) in the \({XH}\) -> \({qqbb}\) final state with the ATLAS detector JF - Physics letters B N2 - A search for heavy resonances decaying into a Higgs boson (H) and a new particle (X) is reported, utilizing 36.1 fb(-1) of proton-proton collision data at root s = 13 TeV collected during 2015 and 2016 with the ATLAS detector at the CERN Large Hadron Collider. The particle Xis assumed to decay to a pair of light quarks, and the fully hadronic final state XH -> q (q) over bar 'b (b) over bar is analysed. The search considers the regime of high XH resonance masses, where the X and H bosons are both highly Lorentz-boosted and are each reconstructed using a single jet with large radius parameter. A two-dimensional phase space of XH mass versus X mass is scanned for evidence of a signal, over a range of XH resonance mass values between 1 TeV and 4 TeV, and for X particles with masses from 50 GeV to 1000 GeV. All search results are consistent with the expectations for the background due to Standard Model processes, and 95% CL upper limits are set, as a function of XH and X masses, on the production cross-section of the XH -> q (q) over bar 'b (b) over bar resonance. (c) 2018 The Author(s). Published by Elsevier B.V. KW - Proton-Proton Collisions KW - Root-S=13 TEV KW - MASS Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-225435 VL - 779 ER - TY - JOUR A1 - Wen, Lai A1 - Feil, Susanne A1 - Wolters, Markus A1 - Thunemann, Martin A1 - Regler, Frank A1 - Schmidt, Kjestine A1 - Friebe, Andreas A1 - Olbrich, Marcus A1 - Langer, Harald A1 - Gawaz, Meinrad A1 - de Wit, Cor A1 - Feil, Robert T1 - A shear-dependent NO-cGMP-cGKI cascade in platelets acts as an auto-regulatory brake of thrombosis JF - Nature Communications N2 - Mechanisms that limit thrombosis are poorly defined. One of the few known endogenous platelet inhibitors is nitric oxide (NO). NO activates NO sensitive guanylyl cyclase (NO-GC) in platelets, resulting in an increase of cyclic guanosine monophosphate (cGMP). Here we show, using cGMP sensor mice to study spatiotemporal dynamics of platelet cGMP, that NO-induced cGMP production in pre-activated platelets is strongly shear-dependent. We delineate a new mode of platelet-inhibitory mechanotransduction via shear-activated NO-GC followed by cGMP synthesis, activation of cGMP-dependent protein kinase I (cGKI), and suppression of Ca2+ signaling. Correlative profiling of cGMP dynamics and thrombus formation in vivo indicates that high cGMP concentrations in shear-exposed platelets at the thrombus periphery limit thrombosis, primarily through facilitation of thrombus dissolution. We propose that an increase in shear stress during thrombus growth activates the NO-cGMP-cGKI pathway, which acts as an auto-regulatory brake to prevent vessel occlusion, while preserving wound closure under low shear. KW - calcium signalling KW - fluorescence imaging KW - platelets KW - thrombosis Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-233616 VL - 9 ER - TY - JOUR A1 - Weigel, Tobias A1 - Schmitz, Tobias A1 - Pfister, Tobias A1 - Gaetzner, Sabine A1 - Jannasch, Maren A1 - Al-Hijailan, Reem A1 - Schürlein, Sebastian A1 - Suliman, Salwa A1 - Mustafa, Kamal A1 - Hansmann, Jan T1 - A three-dimensional hybrid pacemaker electrode seamlessly integrates into engineered, functional human cardiac tissue in vitro JF - Scientific Reports N2 - Pacemaker systems are an essential tool for the treatment of cardiovascular diseases. However, the immune system’s natural response to a foreign body results in the encapsulation of a pacemaker electrode and an impaired energy efficiency by increasing the excitation threshold. The integration of the electrode into the tissue is affected by implant properties such as size, mechanical flexibility, shape, and dimensionality. Three-dimensional, tissue-like electrode scaffolds render an alternative to currently used planar metal electrodes. Based on a modified electrospinning process and a high temperature treatment, a conductive, porous fiber scaffold was fabricated. The electrical and immunological properties of this 3D electrode were compared to 2D TiN electrodes. An increased surface of the fiber electrode compared to the planar 2D electrode, showed an enhanced electrical performance. Moreover, the migration of cells into the 3D construct was observed and a lower inflammatory response was induced. After early and late in vivo host response evaluation subcutaneously, the 3D fiber scaffold showed no adverse foreign body response. By embedding the 3D fiber scaffold in human cardiomyocytes, a tissue-electrode hybrid was generated that facilitates a high regenerative capacity and a low risk of fibrosis. This hybrid was implanted onto a spontaneously beating, tissue-engineered human cardiac patch to investigate if a seamless electronic-tissue interface is generated. The fusion of this hybrid electrode with a cardiac patch resulted in a mechanical stable and electrical excitable unit. Thereby, the feasibility of a seamless tissue-electrode interface was proven. KW - biomedical materials KW - cardiac device therapy KW - hybrid pacemaker Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-177368 VL - 8 IS - 14545 ER - TY - JOUR A1 - Schihada, Hannes A1 - Vandenabeele, Sylvie A1 - Zabel, Ulrike A1 - Frank, Monika A1 - Lohse, Martin J. A1 - Maiellaro, Isabella T1 - A universal bioluminescence resonance energy transfer sensor design enables high-sensitivity screening of GPCR activation dynamics JF - Communications Biology N2 - G-protein-coupled receptors (GPCRs) represent one of the most important classes of drug targets. The discovery of new GCPR therapeutics would greatly benefit from the development of a generalizable high-throughput assay to directly monitor their activation or de-activation. Here we screened a variety of labels inserted into the third intracellular loop and the C-terminus of the alpha(2 Lambda)-adrenergic receptor and used fluorescence (FRET) and bioluminescence resonance energy transfer (BRET) to monitor ligand-binding and activation dynamics. We then developed a universal intramolecular BRET receptor sensor design to quantify efficacy and potency of GPCR ligands in intact cells and real time. We demonstrate the transferability of the sensor design by cloning beta(2)-adrenergic and PTH1-receptor BRET sensors and monitored their efficacy and potency. For all biosensors, the Z factors were well above 0.5 showing the suitability of such design for microtiter plate assays. This technology will aid the identification of novel types of GPCR ligands. KW - Fluorescence resonance energy transfer KW - G protein-coupled receptors KW - High-throughput screening Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-228592 VL - 1 IS - 105 ER - TY - INPR A1 - Werner, Rudolf A. A1 - Andree, Christian A1 - Javadi, Mehrbod S. A1 - Lapa, Constantin A1 - Buck, Andreas K. A1 - Higuchi, Takahiro A1 - Pomper, Martin G. A1 - Gorin, Michael A. A1 - Rowe, Steven P. A1 - Pienta, Kenneth J. T1 - A Voice From the Past: Re-Discovering the Virchow Node with PSMA-targeted \(^{18}\)F-DCFPyL PET Imaging T2 - Urology - The Gold Journal N2 - No abstract available. KW - 18F-DCFPyL KW - Virchow Node KW - PSMA-PET KW - Virchow Node KW - Positron Emission Tomography KW - Prostate Cancer KW - PET Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-161103 SN - 0090-4295 N1 - This is the accepted manuscript of Rudolf Werner, Christian Andree, Mehrbod S. Javadi, Constantin Lapa, Andreas K. Buck, Takahiro Higuchi, Martin G. Pomper, Michael A.Gorin, Steven P.Rowe, Kenneth J. Pienta: A Voice From the Past: Re-Discovering the Virchow Node with PSMA-Targeted 18F-DCFPyL PET Imaging. Published in Urology 117(2018), p. 18-21. https://doi.org/10.1016/j.urology.2018.03.030 N1 - Die finale Version dieses Artikels steht unter https://doi.org/10.1016/j.urology.2018.03.030 oder https://nbn-resolving.org/urn:nbn:de:bvb:20-opus-164632 open access zur Verfügung. ER - TY - JOUR A1 - Werner, Rudolf A. A1 - Andree, Christian A1 - Javadi, Mehrbod S. A1 - Lapa, Constantin A1 - Buck, Andreas K. A1 - Higuchi, Takahiro A1 - Pomper, Martin G. A1 - Gorin, Michael A. A1 - Rowe, Steven P. A1 - Pienta, Kenneth J. T1 - A Voice From the Past: Re-Discovering the Virchow Node with PSMA-targeted \(^{18}\)F-DCFPyL PET Imaging JF - Urology - The Gold Journal N2 - No abstract available. KW - 18F-DCFPyL KW - PET KW - PSMA-PET KW - Positron Emission Tomography KW - Prostate Cancer KW - Virchow Node Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-164632 SN - 0090-4295 VL - 117 ER - TY - INPR A1 - Böhnke, Julian A1 - Arrowsmith, Merle A1 - Braunschweig, Holger T1 - Activation of a Zerovalent Diboron Compound by Desymmetrization T2 - Journal of the American Chemical Society N2 - The desymmetrization of the cyclic (alkyl)(amino)carbene-supported diboracumulene, B\(_2\)(cAAC\(^{Me}\))\(_2\) (cAAC\(^{Me}\) = 1- (2,6-diisopropylphenyl)-3,3,5,5-tetramethylpyrrolidin-2-ylidene) by mono-adduct formation with IMe\(^{Me}\) (1,3-dimethylimidazol-2-ylidene) yields the zerovalent sp-sp\(^2\) diboron compound B\(_2\)(cAAC\(^{Me}\))\(_2\)(IMe\(^{Me}\)), which provides a versatile platform for the synthesis of novel symmetrical and unsymmetrical zerovalent sp\(^2\)-sp\(^2\) diboron compounds by adduct formation with IMe\(^{Me}\) and CO, respectively. Furthermore, B\(_2\)(cAAC\(^{Me}\))\(_2\)(IMe\(^{Me}\)) displays enhanced reactivity compared to its symmetrical precursor, undergoing spontaneous intramolecular C-H activation and facile twofold hydrogenation, the latter resulting in B-B bond cleavage and the formation of the mixed-base parent borylene, (cAAC\(^{Me}\))(IMe\(^{Me}\))BH. KW - diboryne KW - boron KW - carbenes KW - low-valent main group chemistry KW - erovalent diboron compounds KW - desymmetrization KW - bond activation KW - hydrogenation KW - borylene Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-167983 N1 - This document is the unedited Author’s version of a Submitted Work that was subsequently accepted for publication in Journal of the American Chemical Society, copyright © American Chemical Society after peer review. To access the final edited and published work see https://doi.org/10.1021/jacs.8b06930 (Julian Böhnke, Merle Arrowsmith, and Holger Braunschweig: Reactivity Enhancement of a Zerovalent Diboron Compound by Desymmetrization, Journal of the American Chemical Society 2018, 140, (32), 10368-10373. DOI: 10.1021/jacs.8b06930) ER - TY - JOUR A1 - Li, Cong A1 - Deng, Xiaobing A1 - Xie, Xiaowen A1 - Liu, Ying A1 - Friedmann Angeli, José Pedro A1 - Lai, Luhua T1 - Activation of Glutathione Peroxidase 4 as a Novel Anti-inflammatory Strategy JF - Frontiers in Pharmacology N2 - The anti-oxidative enzyme, glutathione peroxidase 4 (GPX4), helps to promote inflammation resolution by eliminating oxidative species produced by the arachidonic acid (AA) metabolic network. Up-regulating its activity has been proposed as a promising strategy for inflammation intervention. In the present study, we aimed to study the effect of GPX4 activator on the AA metabolic network and inflammation related pathways. Using combined computational and experimental screen, we identified a novel compound that can activate the enzyme activity of GPX4 by more than two folds. We further assessed its potential in a series of cellular assays where GPX4 was demonstrated to play a regulatory role. We are able to show that GPX4 activation suppressed inflammatory conditions such as oxidation of AA and NF-κB pathway activation. We further demonstrated that this GPX4 activator can decrease the intracellular ROS level and suppress ferroptosis. Our study suggests that GPX4 activators can be developed as anti-inflammatory or cyto-protective agent in lipid-peroxidation-mediated diseases. KW - arachidonic acid metabolic network KW - GPX4 KW - enzyme activator KW - allosterism KW - drug discovery KW - anti-inflammatory KW - ferroptosis Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-195985 SN - 1663-9812 VL - 9 IS - 1120 ER - TY - JOUR A1 - Kurabi, Arwa A1 - Schaerer, Daniel A1 - Noack, Volker A1 - Bernhardt, Marlen A1 - Pak, Kwang A1 - Alexander, Thomas A1 - Husseman, Jacob A1 - Nguyen, Quyen A1 - Harris, Jeffrey P. A1 - Ryan, Allen F. T1 - Active Transport of Peptides Across the Intact Human Tympanic Membrane JF - Scientific Reports N2 - We previously identified peptides that are actively transported across the intact tympanic membrane (TM) of rats with infected middle ears. To assess the possibility that this transport would also occur across the human TM, we first developed and validated an assay to evaluate transport in vitro using fragments of the TM. Using this assay, we demonstrated the ability of phage bearing a TM-transiting peptide to cross freshly dissected TM fragments from infected rats or from uninfected rats, guinea pigs and rabbits. We then evaluated transport across fragments of the human TM that were discarded during otologic surgery. Human trans-TM transport was similar to that seen in the animal species. Finally, we found that free peptide, unconnected to phage, was transported across the TM at a rate comparable to that seen for peptide-bearing phage. These studies provide evidence supporting the concept of peptide-mediated drug delivery across the intact TM and into the middle ears of patients. KW - assay systems KW - biological models Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-230929 VL - 8 ER - TY - JOUR A1 - Haring, Bernhard A1 - Selvin, Elizabeth A1 - He, Xintong A1 - Coresh, Josef A1 - Steffen, Lyn M. A1 - Folsom, Aaron R. A1 - Tang, Weihong A1 - Rebholz, Casey M. T1 - Adherence to the dietary approaches to stop hypertension dietary pattern and risk of abdominal aortic aneurysm: results from the ARIC study JF - Journal of the American Heart Association N2 - Background The role of a healthy dietary pattern in the prevention of abdominal aortic aneurysms (AAA) is unknown. We aimed to evaluate the relationship between adherence to a Dietary Approaches To Stop Hypertension‐style dietary pattern and the risk of incident AAAs. Methods and Results Dietary intake was assessed via a 66‐item food frequency questionnaire at baseline (1987–1989) and at visit 3 (1993–1995) in 13 496 participants enrolled in the ARIC (Atherosclerosis Risk in Communities) study without clinical AAA (mean age, 54 years). A dietary scoring index based on food times was constructed to assess self‐reported adherence to a dietary approaches to stop hypertension‐style dietary pattern. Participants were followed for incident clinical AAAs using hospital discharge diagnoses, Medicare inpatient and outpatient diagnoses, or death certificates through December 31, 2011. Cox proportional hazards models with covariate adjustment were used to estimate hazard ratios with 95% confidence intervals. During a median follow‐up of 23 years, there were 517 incident AAA cases. Individuals with a Dietary Approaches To Stop Hypertension‐style diet score in the highest quintile had a 40% lower risk of hospitalization for AAA than those in the lowest quintile (hazard ratio\(_{Q5}\) vs \(_{Q1}\): 0.60; 95% confidence intervals: 0.44, 0.83; P\(_{trend}\)=0.002). In detailed analyses, higher consumption of fruits, vegetables, whole grains, low‐fat dairy, and nuts and legumes was related to a lower risk for AAA. Conclusions Greater adherence to a Dietary Approaches To Stop Hypertension‐style dietary pattern was associated with lower risk for AAA. Higher consumption of fruits, vegetables, whole grains, low‐fat dairy as well as nuts and legumes may help to decrease the burden of AAAs. KW - diet KW - dietary approaches to stop hypertension KW - aneurysm Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-177442 VL - 7 IS - 21 ER - TY - THES A1 - Balzer, Christian T1 - Adsorption-Induced Deformation of Nanoporous Materials — in-situ Dilatometry and Modeling T1 - Adsorptionsinduzierte Deformation nanoporöser Materialien — in-situ Dilatometrie und Modellierung N2 - The goal of this work is to improve the understanding of adsorption-induced deformation in nanoporous (and in particular microporous) materials in order to explore its potential for material characterization and provide guidelines for related technical applications such as adsorption-driven actuation. For this purpose this work combines in-situ dilatometry measurements with in-depth modeling of the obtained adsorption-induced strains. A major advantage with respect to previous studies is the combination of the dilatometric setup and a commercial sorption instrument resulting in high quality adsorption and strain isotherms. The considered model materials are (activated and thermally annealed) carbon xerogels, a sintered silica aerogel, a sintered hierarchical structured porous silica and binderless zeolites of type LTA and FAU; this selection covers micro-, meso- and macroporous as well as ordered and disordered model materials. All sample materials were characterized by scanning electron microscopy, gas adsorption and sound velocity measurements. In-situ dilatometry measurements on mesoporous model materials were performed for the adsorption of N2 at 77 K, while microporous model materials were also investigated for CO2 adsorption at 273 K, Ar adsorption at 77 K and H2O adsorption at 298 K. Within this work the available in-situ dilatometry setup was revised to improve resolution and reproducibility of measurements of small strains at low relative pressures, which are of particular relevance for microporous materials. The obtained experimental adsorption and strain isotherms of the hierarchical structured porous silica and a micro-macroporous carbon xerogel were quantitatively analyzed based on the adsorption stress model; this approach, originally proposed by Ravikovitch and Neimark, was extended for anisotropic pore geometries within this work. While the adsorption in silica mesopores could be well described by the classical and analytical theory of Derjaguin, Broekhoff and de Boer, the adsorption in carbon micropores required for comprehensive nonlocal density functional theory calculations. To connect adsorption-induced stresses and strains, furthermore mechanical models for the respective model materials were derived. The resulting theoretical framework of adsorption, adsorption stress and mechanical model was applied to the experimental data yielding structural and mechanical information about the model materials investigated, i.e., pore size or pore size distribution, respectively, and mechanical moduli of the porous matrix and the nonporous solid skeleton. The derived structural and mechanical properties of the model materials were found to be consistent with independent measurements and/or literature values. Noteworthy, the proposed extension of the adsorption stress model proved to be crucial for the correct description of the experimental data. Furthermore, it could be shown that the adsorption-induced deformation of disordered mesoporous aero-/xerogel structures follows qualitatively the same mechanisms obtained for the ordered hierarchical structured porous silica. However, respective quantitative modeling proved to be challenging due to the ill-shaped pore geometry of aero-/xerogels; good agreement between model and experiment could only be achieved for the filled pore regime of the adsorption isotherm and the relative pressure range of monolayer formation. In the intermediate regime of multilayer formation a more complex model than the one proposed here is required to correctly describe stress related to the curved adsorbate-adsorptive interface. Notably, for micro-mesoporous carbon xerogels it could be shown that micro- and mesopore related strain mechanisms superimpose one another. The strain isotherms of the zeolites were only qualitatively evaluated. The result for the FAU type zeolite is in good agreement with other experiments reported in literature and the theoretical understanding derived from the adsorption stress model. On the contrary, the strain isotherm of the LTA type zeolite is rather exceptional as it shows monotonic expansion over the whole relative pressure range. Qualitatively this type of strain isotherm can also be explained by the adsorption stress model, but a respective quantitative analysis is beyond the scope of this work. In summary, the analysis of the model materials' adsorption-induced strains proved to be a suitable tool to obtain information on their structural and mechanical properties including the stiffness of the nonporous solid skeleton. Investigations on the carbon xerogels modified by activation and thermal annealing revealed that adsorption-induced deformation is particularly suited to analyze even small changes of carbon micropore structures. N2 - Ziel dieser Arbeit ist es, dass Verständnis der adsorptionsinduzierter Deformation von nanoporösen (insbesondere mikroporösen) Materialien zu erweitern, um ihr Potenzial für die Materialcharakterisierung zu erforschen. Zusätzlich sollen Orientierungshilfen für technische Anwendungen, wie z.B. adsorptionsgetriebene Aktuatoren, bereitgestellt werden. Hierfür kombiniert diese Arbeit in-situ Dilatometriemessungen und detaillierte Modellierung der gemessenen adsorptionsinduzierten Dehnungen. Der wesentliche Vorteil dieser Arbeit gegenüber vorherigen Studien ist die Kombination des dilatometrischen Messaufbaus mit einer kommerziellen Gasadsorptionsanlage, was die Messung qualitativ hochwertiger Adsorptions- und Dehnungsisothermen erlaubt. Die betrachteten Materialsysteme sind (aktivierte und geglühte) Kohlenstoffxerogele, ein gesintertes Silica-Aerogel, ein gesintertes, hierarchisch strukturiertes, poröses Silica und binderlose Zeolithe der Typen LTA und FAU. Diese Auswahl umfasst mikro-, meso- und makroporöse ebenso wie geordnete und ungeordnete Modellmaterialien. Alle Modellmaterialien wurden mit Rasterelektronenmikroskopie, Gasadsorption und Schallgeschwindigkeitsmessungen charakterisiert. In-situ Dilatometriemessungen an mesoporösen Modellsystemen wurden für N2-Adsorption bei 77 K durchgeführt, während alle mikroporösen Modellsysteme zusätzlich bei CO2-Adsorption (273 K), Ar-Adsorption (77 K) und H2O-Adsorption (298 K) untersucht wurden. Der verfügbare Messaufbau für in-situ Dilatometrie wurde im Rahmen dieser Arbeit weiterentwickelt, um Auflösung und Reproduzierbarkeit der Messungen von kleinen Dehnungen zu verbessern, was insbesondere für mikroporöse Materialien von Bedeutung ist. Die experimentellen Adsorptions- und Dehnungsisothermen des hierarchisch strukturierten, porösen Silicas und des mikro-makroporösen Kohlenstoff-Xerogels wurden mit dem adsorption-stress-Modell quantitativ ausgewertet. Hierfür wurde das adsorption-stress-Modell, ursprünglich eingeführt von Ravikovitch et al., für die Verwendung von anisotropen Porengeometrien erweitert. Während die der Deformation zu Grunde liegende Adsorption im Fall des mesoporösen Silicas gut mit der klassischen und analytischen Theorie von Derjaguin, Broekhoff und de Boer beschrieben werden konnte, erforderte die Adsorption in den Kohlenstoffmikroporen umfassende Berechnungen mittels nichtlokaler Dichtefunktionaltheorie. Um die adsorptionsinduzierten Spannungen mit entsprechenden Dehnungen zu korrelieren, wurden zusätzlich mechanische Modelle für die untersuchten Materialien entworfen. Das resultierende theoretische Konstrukt aus Adsorptions-, adsorption-stress- und mechanischem Modell wurde auf die ermittelten experimentellen Daten angewandt und strukturelle und mechanische Eigenschaften der Modellmaterialien bestimmt, d.h. Porengröße bzw. Porengrößenverteilung sowie die mechanischen Module der porösen Matrix und des unporösen Festkörperskeletts. Es konnte gezeigt werden, dass die ermittelten Materialeigenschaften konsistent mit unabhängigen Messungen und/oder Literaturwerten sind. Hierbei ist zu beachten, dass sich die Erweiterung des adsorption-stress-Modells für eine korrekte Auswertung der experimentellen Daten als zwingend erforderlich erwies. Des Weiteren konnte gezeigt werden, dass die adsorptionsinduzierte Deformation von ungeordneten mesoporösen Aero-/Xerogelstrukturen qualitativ denselben Mechanismen folgt, die für das geordnete, hierarchisch strukturierte, poröse Silica identifiziert wurden. Die entsprechende quantitative Modellierung erwies sich allerdings als schwierig, da die Poren in Aero-/Xerogelstrukturen geometrisch schlecht zu fassen sind. Gute Übereinstimmung zwischen Modell und Experiment konnte nur für das Stadium gefüllter Poren und den relativen Druckbereich der Monolagenbildung erzielt werden. Der Zwischenbereich der Multilagenadsorption erfordert ein komplexeres Modell, um die Spannung quantitativ korrekt zu beschreiben, die sich auf Grund der gekrümmten Adsorbat-Adsorptiv-Grenzfläche im Material ausbildet. Mit Hinblick auf mikro-mesoporöse Kohlenstoffxerogele konnte gezeigt werden, dass sich dort Deformationsmechanismen von Mikro- und Mesoporen überlagern. Die Dehnungsisothermen der Zeolithe wurden nur qualitativ ausgewertet. Das Ergebnis für den Zeolithen vom Typ FAU stimmt gut mit anderen in der Literatur beschriebenen Experimenten und dem theoretischen Verständnis überein, das sich aus dem adsorption-stress-Modell ergibt. Im Gegensatz dazu ist die gemessene Dehnungsisotherme des Zeolithen vom Typ LTA eher ungewöhnlich, da sie monotone Expansion des LTA-Zeolithen über den gesamten Druckbereich zeigt. Qualitativ kann dieses Ergebnis ebenfals mit dem adsorption-stress-Modell erklärt werden, aber eine detaillierte, quantitative Analyse übersteigt den Rahmen dieser Arbeit. Insgesamt erweist sich die Analyse der adsorptionsinduzierten Dehnungen der Modellmaterialien als geeignetes Mittel, um Informationen über deren strukturelle und mechanische Eigenschaften zu erlangen, was auch die Steifigkeit des unporösen Festkörperskeletts miteinschließt. Desweiteren zeigen Untersuchungen an aktivierten und geglühten Kohlenstoffxerogelen, dass adsorptionsinduzierte Deformation insbesondere geeignet ist, um kleine Änderungen an Mikroporenstrukturen zu analysieren. KW - Nanoporöser Stoff KW - Adsorption KW - Deformation KW - Dilatometrie KW - adsorption-induced deformation KW - density functional theory KW - adsorption KW - deformation KW - nanostructured KW - dilatometer KW - modeling Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-157145 ER - TY - THES A1 - Hochleitner, Gernot T1 - Advancing melt electrospinning writing for fabrication of biomimetic structures T1 - Entwicklung des Melt Electrospinning Writing zur Erzeugung biomimetischer Strukturen N2 - In order to mimic the extracellular matrix for tissue engineering, recent research approaches often involve 3D printing or electrospinning of fibres to scaffolds as cell carrier material. Within this thesis, a micron fibre printing process, called melt electrospinning writing (MEW), combining both additive manufacturing and electrospinning, has been investigated and improved. Thus, a unique device was developed for accurate process control and manufacturing of high quality constructs. Thereby, different studies could be conducted in order to understand the electrohydrodynamic printing behaviour of different medically relevant thermoplastics as well as to characterise the influence of MEW on the resulting scaffold performance. For reproducible scaffold printing, a commonly occurring processing instability was investigated and defined as pulsing, or in extreme cases as long beading. Here, processing analysis could be performed with the aim to overcome those instabilities and prevent the resulting manufacturing issues. Two different biocompatible polymers were utilised for this study: poly(ε-caprolactone) (PCL) as the only material available for MEW until then and poly(2-ethyl-2-oxazoline) for the first time. A hypothesis including the dependency of pulsing regarding involved mass flows regulated by the feeding pressure and the electrical field strength could be presented. Further, a guide via fibre diameter quantification was established to assess and accomplish high quality printing of scaffolds for subsequent research tasks. By following a combined approach including small sized spinnerets, small flow rates and high field strengths, PCL fibres with submicron-sized fibre diameters (fØ = 817 ± 165 nm) were deposited to defined scaffolds. The resulting material characteristics could be investigated regarding molecular orientation and morphological aspects. Thereby, an alignment and isotropic crystallinity was observed that can be attributed to the distinct acceleration of the solidifying jet in the electrical field and by the collector uptake. Resulting submicron fibres formed accurate but mechanically sensitive structures requiring further preparation for a suitable use in cell biology. To overcome this handling issue, a coating procedure, by using hydrophilic and cross-linkable star-shaped molecules for preparing fibre adhesive but cell repellent collector surfaces, was used. Printing PCL fibre patterns below the critical translation speed (CTS) revealed the opportunity to manufacture sinusoidal shaped fibres analogously to those observed using purely viscous fluids falling on a moving belt. No significant influence of the high voltage field during MEW processing could be observed on the buckling phenomenon. A study on the sinusoidal geometry revealed increasing peak-to-peak values and decreasing wavelengths as a function of decreasing collector speeds sc between CTS > sc ≥ 2/3 CTS independent of feeding pressures. Resulting scaffolds printed at 100 %, 90 %, 80 % and 70 % of CTS exhibited significantly different tensile properties, foremost regarding Young’s moduli (E = 42 ± 7 MPa to 173 ± 22 MPa at 1 – 3 % strain). As known from literature, a changed morphology and mechanical environment can impact cell performance substantially leading to a new opportunity of tailoring TE scaffolds. Further, poly(L-lactide-co-ε-caprolactone-co-acryloyl carbonate) as well as poly(ε-caprolactone-co-acryloyl carbonate) (PCLAC) copolymers could be used for MEW printing. Those exhibit the opportunity for UV-initiated radical cross-linking in a post-processing step leading to significantly increased mechanical characteristics. Here, single fibres of the polymer composed of 90 mol.% CL and 10 mol.% AC showed a considerable maximum tensile strength of σmax = 53 ± 16 MPa. Furthermore, sinusoidal meanders made of PCLAC yielded a specific tensile stress-strain characteristic mimicking the qualitative behaviour of tendons or ligaments. Cell viability by L929 murine fibroblasts and live/dead staining with human mesenchymal stem cells revealed a promising biomaterial behaviour pointing out MEW printed PCLAC scaffolds as promising choice for medical repair of load-bearing soft tissue. Indeed, one apparent drawback, the small throughput similar to other AM methods, may still prevent MEW’s industrial application yet. However, ongoing research focusses on enlargement of manufacturing speed with the clear perspective of relevant improvement. Thereby, the utilisation of large spinneret sizes may enable printing of high volume rates, while downsizing the resulting fibre diameter via electrical field and mechanical stretching by the collector uptake. Using this approach, limitations of FDM by small nozzle sizes could be overcome. Thinking visionary, such printing devices could be placed in hospitals for patient-specific printing-on-demand therapies one day. Taking the evolved high deposition precision combined with the unique small fibre diameter sizes into account, technical processing of high performance membranes, filters or functional surface finishes also stands to reason. N2 - Um biomimetische extrazelluläre Matrices für das Tissue Engineering herzustellen, bedienen sich aktuelle Forschungsansätze oftmals der Produktion von Faser-Konstrukten durch additive Fertigung oder Elektrospinn-Verfahren. Das sogenannte Melt Electrospinning Writing (MEW) kombiniert Vorteile beider Techniken und weist dadurch ein hohes Applikationspotential auf. Daher bestand das Ziel der vorliegenden Arbeit in der Weiterentwicklung und Erforschung des MEW. Für diesen Zweck wurde eine neuartige Forschungsanlage konzipiert und gebaut, welche mit einzigartiger Verfahrenspräzision und Prozesskontrolle die Fertigung von hochqualitativen Konstrukten ermöglichte. Auf Basis dessen konnten die durchgeführten Studien das Verständnis des elektrohydrodynamischen Druckvorgangs und der untersuchten Prozessparameter vertiefen und letztendlich zur Ausweitung des Verfahrens auf neue medizinisch relevante Thermoplaste beitragen. Um eine reproduzierbare Herstellung von Scaffolds zu ermöglichen, wurde eine häufig auftretende Prozessinstabilität erforscht und als pulsing, oder in stark ausgeprägten Fällen als long beading, klassifiziert. Durch Prozessanalyse konnte zudem eine Methode zur Vermeidung dieser Instabilität entwickelt werden. Dafür wurden zwei unterschiedliche biokompatible Polymere verwendet: Poly(ε-Caprolacton) (PCL) als bis dahin einziger verfügbarer MEW Werkstoff, sowie erstmalig Poly(2-Ethyl-2-Oxazolin). Die aufgestellte Hypothese umfasst eine universelle Abhängigkeit der pulsing Instabilität zu involvierten Massenströmen, welche durch Anpassung des angelegten Prozessdruckes und der elektrischen Feldstärke reguliert werden kann. Um ein optimales Prozessergebnis für nachfolgende Forschungsarbeiten zu erzielen, wurde zusätzlich ein Leitfaden zur quantitativen Bewertung des Grades der Instabilität bereitgestellt. Durch Kombination kleiner Spinndüsen, kleiner Schmelze-Flussraten und hoher elektrischen Feldstärken, konnten erstmalig PCL Fasern mit sub-mikron Durchmessern (fØ = 817 ± 165 nm) zu präzisen Scaffolds verarbeitet werden. Diese wurden anschließend durch materialwissenschaftliche Analytik charakterisiert. Dabei wurde eine molekulare Vorzugsorientierung und isotrope Kristallausrichtung entlang der Faser beobachtet, welche durch den hohen Verstreckungsgrad des erstarrenden Polymerstrahls erklärt werden konnte. Resultierende sub-mikron Fasern konnten zwar für einen akkuraten Druckvorgang verwendet werden, jedoch erwiesen sich die Strukturen als instabil und daher nicht geeignet für die Handhabung bei Zellkulturstudien. Aus diesem Grund wurde ein Beschichtungsansatz mittels hydrophilen und vernetzbaren Sternmolekülen für Substratflächen herangezogen. Während solche modifizierten Oberflächen bekanntermaßen Zelladhäsion verhindern, konnten gedruckte sub-mikron Scaffolds auf der Oberfläche haften und so für biologische Studien verwendet werden. Durch das gezielte Ablegen von Fasern unterhalb der kritischen Translationsgeschwindigkeit (CTS) des Kollektors, konnten sinusförmige Faserstrukturen erzeugt werden. Analog zu rein viskosen Fluiden, welche durch ein bewegliches Band aufgesammelt werden, schien dieser Vorgang dem sogenannten buckling zu unterliegen und daher phänomenologisch nicht oder nur geringfügig vom elektrischen Feld abhängig zu sein. Zudem konnte eine durchgeführte Studie die direkte Abhängigkeit der Fasergeometrie mit der Kollektorbewegung belegen. Unabhängig vom Prozessdruck, führte eine verminderte Kollektorgeschwindigkeit sc in den Grenzen CTS > sc ≥ 2/3 CTS zu erhöhten Amplituden bzw. Spitze-zu-Spitze Werten und verkürzten Wellenlängen. Durch das kontrollierte Ablegen der Fasern bei Geschwindigkeiten von 100 %, 90 % 80 % und 70 % CTS konnten zudem Scaffolds mit unterschiedlichen mechanischen Eigenschaften hergestellt werden. Speziell der Zugmodul wurde dadurch etwa um eine halbe Größenordnung moduliert (Es = 42 ± 7 MPa bis 173 ± 22 MPa bei 1 – 3 % Dehnung). Dies ist in Kombination mit der Strukturierung für maßgeschneiderte TE Scaffolds von großem Interesse, da zelluläre Systeme sensibel auf ihre Umgebung reagieren können. Des Weiteren wurden Poly(L-Lactid-co-ε-Caprolacton-co-Acryloylcarbonat) und Poly(ε-Caprolacton-co-Acryloylcarbonat) (PCLAC) Copolymere hinsichtlich deren MEW Verarbeitbarkeit untersucht. Solche Kunststoffe können nach dem Druckvorgang mit UV-Strahlung radikalisch vernetzt werden und dadurch deutlich erhöhte mechanische Eigenschaften ausbilden. Für Fasern aus 90 mol.% CL und 10 mol.% AC wurden beispielsweise maximale Zugfestigkeiten von σmax = 53 ± 16 MPa ermittelt. MEW gedruckte sinusförmige Faserstrukturen aus PCLAC wiesen darüber hinaus ein biomimetisches Spannungs-Dehnung-Verhalten auf, vergleichbar zu Sehnen- und Ligamentgewebe. Eine Untersuchung der Zellviabilität von L929 murinen Fibroblasten im Eluattest, sowie eine lebend/tot-Färbung von humanen mesenchymalen Stammzellen auf den Scaffolds, ergab vielversprechende Resultate und damit ein relevantes Anwendungspotential solcher Strukturen als Implantat. Neben genannten Vorteilen, weist MEW als Verfahren bislang allerdings geringe Produktionsgeschwindigkeiten auf. Diese sind daher in den Fokus aktueller Forschungsvorhaben gerückt. Einen Ansatz hierfür bieten Spinndüsen mit hohem Innendurchmesser und erhöhter Austragsrate, wobei die optimierte elektrische Feldstärke, sowie ein Verstrecken durch die Kollektorbewegung, zu den erwünschten dünnen Fasern führen können. Dadurch kann die abwärtslimitierte Düsengröße des FDM Verfahrens überwunden werden. Visionär gedacht, könnte eine solche Anlage direkt in Krankenhäusern zur Fertigung von patienten- und defektspezifischen Implantaten eingesetzt werden. Darüber hinaus ermöglicht die hohe Präzision, zusammen mit dem Drucken von Mikro-Fasern, einen technischen Einsatz zur Herstellung von Membranen, Filtern oder funktionalen Oberflächenbeschichtungen. KW - scaffold KW - polymer KW - 3D printing KW - additive manufacturing KW - melt electrospinning KW - melt electrowriting KW - tissue engineering KW - polymer processing Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-162197 ER - TY - JOUR A1 - Suchotzki, Kristina A1 - Gamer, Matthias T1 - Alcohol facilitates detection of concealed identity information JF - Scientific Reports N2 - The Concealed Information Test (CIT) is a well-validated means to detect whether someone possesses certain (e.g., crime-relevant) information. The current study investigated whether alcohol intoxication during CIT administration influences reaction time (RT) CIT-effects. Two opposing predictions can be made. First, by decreasing attention to critical information, alcohol intoxication could diminish CIT-effects. Second, by hampering the inhibition of truthful responses, alcohol intoxication could increase CIT-effects. A correlational field design was employed. Participants (n = 42) were recruited and tested at a bar, where alcohol consumption was voluntary and incidental. Participants completed a CIT, in which they were instructed to hide knowledge of their true identity. BAC was estimated via breath alcohol ratio. Results revealed that higher BAC levels were correlated with higher CIT-effects. Our results demonstrate that robust CIT effects can be obtained even when testing conditions differ from typical laboratory settings and strengthen the idea that response inhibition contributes to the RT-CIT effect. KW - drug regulation KW - human behaviour KW - alcohol KW - Concealed Information Test KW - reaction time Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-176662 VL - 8 IS - 7825 ER - TY - JOUR A1 - Rodrigues, Johannes A1 - Nagowski, Natalie A1 - Mussel, Patrick A1 - Hewig, Johannes T1 - Altruistic punishment is connected to trait anger, not trait altruism, if compensation is available JF - Heliyon N2 - Altruistic punishment and altruistic compensation are important concepts that are used to investigate altruism. However, altruistic punishment has been found to be correlated with anger. We were interested whether altruistic punishment and altruistic compensation are both driven by trait altruism and trait anger or whether the influence of those two traits is more specific to one of the behavioral options. We found that if the participants were able to apply altruistic compensation and altruistic punishment together in one paradigm, trait anger only predicts altruistic punishment and trait altruism only predicts altruistic compensation. Interestingly, these relations are disguised in classical altruistic punishment and altruistic compensation paradigms where participants can either only punish or compensate. Hence altruistic punishment and altruistic compensation paradigms should be merged together if one is interested in trait altruism without the confounding influence of trait anger. KW - psychology KW - altruism KW - altruistic punishment KW - altruistic compensation KW - anger Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-177669 VL - 4 IS - 11 ER - TY - JOUR A1 - Schairer, Patrick A1 - Wagner, Stephan A1 - Geidel, Ekkehard T1 - An experimental introduction to basic principles of the interaction of electromagnetic radiation with matter JF - World Journal of Chemical Education N2 - To understand basic principles about the interaction of electromagnetic radiation with matter is often a challenge in chemical education due to the difficult theoretical background of this topic. The present contribution therefore offers an experimental based introduction into the basic principles of UV/Vis spectroscopy following a three-step strategy. The starting point is to construct a simple self-built spectrometer working within the visible range of light. Learners can explore the most important components of such a device and understand their functions without previous knowledge. In a second step, emission spectra of different common light sources are investigated and compared. Finally, spectroscopic experiments are suggested for chemical education such as the qualitative detection of cations and the quantitative analysis of the dye carmine in food. This context-based introduction links chemical applications with the everyday life. It can be presumed that this way, learners are provided an easier access to radiation-matter interaction. KW - UV/Vis spectroscopy KW - low-cost spectrometer KW - flame test KW - quantitative analysis KW - carmine Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-175811 VL - 6 IS - 1 ER - TY - THES A1 - Hampe, Irene Aurelia Ida T1 - Analysis of the mechanism and the regulation of histatin 5 resistance in \(Candida\) \(albicans\) T1 - Analyse des Mechanismus und der Regulierung von Histatin 5 Resistenz in \(Candida\) \(albicans\) N2 - Antimycotics such as fluconazole are frequently used to treat C. albicans infections of the oral mucosa. Prolonged treatment of the fungal infection with fluconazole pose a risk to resistance development. C. albicans can adapt to these stressful environmental changes by regulation of gene expression or by producing genetically altered variants that arise in the population. Adapted variants frequently carry activating mutations in zinc cluster transcription factors, which cause the upregulation of their target genes, including genes encoding efflux pumps that confer drug resistance. MDR1, regulated by the zinc cluster transcription factor Mrr1, as well as CDR1 and CDR2, regulated by the zinc cluster transcription factor Tac1, are well-known examples of genes encoding efflux pumps that extrude the antimycotic fluconazole from the fungal cell and thus contribute to the survival of the fungus. In this study, it was investigated if C. albicans can develop resistance to the antimicrobial peptide histatin 5, which serves as the first line of defence in the oral cavity of the human host. Recently, it was shown that C. albicans transports histatin 5 outside of the Candia cell via the efflux pump Flu1. As efflux pumps are often regulated by zinc cluster transcription factors, the Flu1 efflux pump could also be regulated by a zinc cluster transcription factor which could in a hyperactive form upregulate the expression of the efflux pump, resulting in increased export of histatin 5 and consequently in histatin 5 resistance. In order to find a zinc cluster transcription factor that upregulates FLU1 expression, a comprehensive library of C. albicans strains containing artificially activated forms of zinc cluster transcription factors was screened for suitable candidates. The screening was conducted on medium containing mycophenolic acid because mycophenolic acid is also a substrate of Flu1 and a strain expressing a hyperactive zinc cluster transcription factor that upregulates FLU1 expression should exhibit an easily recognisable mycophenolic acid-resistant phenotype. Further, FACS analysis, quantitative real-time RT-PCR analysis, broth microdilution assays as well as histatin 5 assays were conducted to analyse the mechanism and the regulation of histatin 5 resistance. Several zinc cluster transcription factors caused mycophenolic acid resistance and upregulated FLU1 expression. Of those, only hyperactive Mrr1 was able to confer increased histatin 5 resistance. Finding Mrr1 to confer histatin 5 resistance was highly interesting as fluconazole-resistant strains with naturally occurring Mrr1 gain of function mutations exist, which were isolated from HIV-infected patients with oral candidiasis. These Mrr1 gain of function mutations as well as artificially activated Mrr1 cause fluconazole resistance by upregulation of the efflux pump MDR1 and other target genes. In the course of the study, it was found that expression of different naturally occurring MRR1 gain-of-function mutations in the SC5314 wild type background caused increased FLU1 expression and increased histatin 5 resistance. The same was true for fluconazole-resistant clinical isolates with Mrr1 gain of function mutations, which also caused the overexpression of FLU1. Those cells were less efficiently killed by histatin 5 dependent on Mrr1. Surprisingly, FLU1 contributed only little to histatin 5 resistance, rather, overexpression of MDR1 mainly contributed to the Mrr1-mediated histatin 5 resistance, but also additional Mrr1-target genes were involved. These target genes are yet to be uncovered. Moreover, if a link between the yet unknown Mrr1-target genes contributing to fluconazole resistance and increased histatin 5 resistance can be drawn remains to be discovered upon finding of the responsible target genes. Collectively, this study contributes to the understanding of the impact of prolonged antifungal exposure on the interaction between host and fungus. Drug therapy can give rise to resistance evolution resulting in strains that have not only developed resistance to fluconazole but also to an innate host mechanism, which allows adaption to the host niche even in the absence of the drug. N2 - Antimykotika wie Fluconazol werden häufig zur Behandlung von C. albicans Infektionen der Mundschleimhaut verwendet. Dabei stellt eine langzeitige Behandlung der Pilzinfektion mit Fluconazol ein Risiko zur Resistenzentwicklung dar. C. albicans kann sich an solche Umweltveränderungen anpassen, indem es die Genexpression reguliert oder genetisch veränderte Varianten produziert, welche in der Population entstehen. Adaptierte Varianten tragen häufig aktivierende Mutationen in Zink-Cluster-Transkriptionsfaktoren, welche die Hochregulierung der Expression von Genen verursachen, darunter solche, die für Multidrug-Effluxpumpen kodieren und dadurch Antimykotikaresistenz verleihen können. MDR1, reguliert durch den Zink-Cluster-Transkriptionsfaktor Mrr1, sowie CDR1 und CDR2, reguliert durch den Zink-Cluster-Transkriptionsfaktor Tac1, sind bekannte Beispiele für Effluxpumpen, die das Antimykotikum Fluconazol aus der Pilzzelle extrudieren und somit zum Überleben der Pilzzelle beitragen. In dieser Arbeit wurde untersucht, ob C. albicans eine Resistenz gegen das antimikrobielle Peptid Histatin 5 entwickeln kann, das in der Mundhöhle des menschlichen Wirtes als erste Verteidigungsbarriere gegen den Pilz dient. Kürzlich wurde gezeigt, dass C. albicans Histatin 5 über die Effluxpumpe Flu1 aus der Candia-Zelle heraustransportiert (Li et al., 2013). Da Effluxpumpen häufig durch Zink-Cluster-Transkriptionsfaktoren reguliert werden, könnte auch die Flu1-Effluxpumpe durch solch einen Transkriptionsfaktor reguliert werden, der in einer hyperaktiven Form die Expression der Effluxpumpe hochregulieren könnte, was wiederrum zu einem erhöhten Export von Histatin 5 und folglich zur Histatin 5 Resistenz führen könnte. Um einen Zink-Cluster-Transkriptionsfaktor zu finden, der die FLU1-Expression hochreguliert, wurde mit Hilfe einer Bibliothek von C. albicans-Stämmen, die künstlich aktivierte Formen von Zink-Cluster-Transkriptionsfaktoren enthält, nach geeigneten Kandidaten gesucht. Das Screening wurde auf Mycophenolsäure-haltigem Medium durchgeführt, da Mycophenolsäure ebenfalls ein Substrat von Flu1 ist. Folglich sollte ein Stamm mit hyperaktivem Zink-Cluster-Transkriptionsfaktor, welcher die FLU1-Expression hochreguliert, einen leicht erkennbaren Mycophenolsäure-resistenten Phänotyp aufweisen. Weiterhin wurden FACS-Analysen, quantitative real-time RT-PCR-Analysen, Broth microdilution-Assays sowie Histatin 5-Assays durchgeführt, um den Mechanismus und die Regulierung der Histatin-5-Resistenz zu analysieren. Mehrere Zink-Cluster-Transkriptionsfaktoren verursachten Mycophenolsäure-Resistenz und erhöhten die FLU1-Expression. Von diesen war nur hyperaktives Mrr1 in der Lage, eine erhöhte Histatin-5-Resistenz zu verleihen. Das Auffinden von Mrr1 als Regulator der Histatin 5-Resistenz war hochinteressant, da fluconazolresistente Stämme mit natürlich vorkommenden MRR1 gain-of-function Mutationen existieren, die aus HIV-infizierten Patienten mit oropharyngealer Candidiasis isoliert wurden. Diese gain-of-function Mutationen sowie künstlich aktivierendes Mrr1 verursachen Fluconazol-Resistenz durch Hochregulation der Effluxpumpe MDR1 und anderer Zielgene. Im Verlauf der Studie wurde herausgefunden, dass verschiedene natürlich vorkommende MRR1 gain-of-function Mutationen im SC5314 Wildtyp Hintergrund eine erhöhte FLU1-Expression und eine erhöhte Histatin-5-Resistenz verursachten. Das Gleiche galt für Fluconazol-resistente klinische Isolate mit Mrr1 gain-of-function Mutationen, welche die Überexpression von FLU1 verursachten. Zellen dieser Isolate wurden, abhängig von Mrr1, weniger wirksam durch Histatin 5 abgetötet. Überraschenderweise trug FLU1 nur wenig zur Histatin-5-Resistenz bei, vielmehr trug die Überexpression von MDR1 hauptsächlich zur Mrr1-vermittelten Histatin-5-Resistenz bei, aber auch weitere Mrr1-Zielgene waren daran beteiligt. Diese Mrr1-Zielgene gilt es nun noch zu entdecken. Ob ein Zusammenhang zwischen diesen noch unbekannten Mrr1-Zielgenen hergestellt werden kann, die zur Fluconazolresistenz sowie zu einer erhöhten Histatin-5-Resistenz beitragen, wird erst nach dem Auffinden der verantwortlichen Zielgene geprüft werden können. Zusammenfassend trägt diese Studie zum Verständnis der Auswirkungen einer anhaltenden antimykotischen Exposition auf die Interaktion zwischen Wirt und Pilz bei. Eine medikamentöse Therapie kann zu einer Resistenzentwicklung führen, aus der Stämme hervorgehen, welche nicht nur eine Resistenz gegen Fluconazol entwickelt haben, sondern gleichzeitig eine Resistenz gegen einen angeborenen Wirtsabwehrmechanismus, der eine Adaption an die Wirtsnische auch in Abwesenheit des Antimykotikums ermöglicht. KW - Histatin 5 KW - Candida albicans KW - Efflux pump KW - MDR1 KW - MRR1 KW - Mrr1 KW - MDR1 KW - Fluconazole KW - Efflux pump Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-159634 ER - TY - JOUR T1 - Angular analysis of B-d(0) -> K* µ\(^+\)μ\(^-\) decays in \({pp}\) collisions at root s=8 TeV with the ATLAS detector JF - Journal of High Energy Physics N2 - An angular analysis of the decay B-d(0) -> K*mu(+)mu(-) is presented, based on proton-proton collision data recorded by the ATLAS experiment at the LHC. The study is using 20.3 fb(-1) of integrated luminosity collected during 2012 at centre-of-mass energy of root s = 8TeV. Measurements of the K* longitudinal polarisation fraction and a set of angular parameters obtained for this decay are presented. The results are compatible with the Standard Model predictions. KW - Hadron-Hadron scattering (experiments) KW - K* µ+μ− KW - B-0 Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-220670 VL - 47 ER - TY - JOUR A1 - Fischer, Matthias A1 - Raabe, Thomas T1 - Animal models for Coffin-Lowry syndrome: RSK2 and nervous system dysfunction JF - Frontiers in Behavioral Neuroscience N2 - Loss of function mutations in the rsk2 gene cause Coffin-Lowry syndrome (CLS), which is associated with multiple symptoms including severe mental disabilities. Despite the characterization of ribosomal S6 kinase 2 (RSK2) as a protein kinase acting as a downstream effector of the well characterized ERK MAP-kinase signaling pathway, it turns out to be a challenging task to link RSK2 to specific neuronal processes dysregulated in case of mutation. Animal models such as mouse and Drosophila combine advanced genetic manipulation tools with in vivo imaging techniques, high-resolution connectome analysis and a variety of behavioral assays, thereby allowing for an in-depth analysis for gene functions in the nervous system. Although modeling mental disability in animal systems has limitations because of the complexity of phenotypes, the influence of genetic variation and species-specific characteristics at the neural circuit and behavioral level, some common aspects of RSK2 function in the nervous system have emerged, which will be presented. Only with this knowledge our understanding of the pathophysiology of CLS can be improved, which might open the door for development of potential intervention strategies. KW - Coffin-Lowry syndrome KW - RSK2 KW - mental disorders KW - mouse model KW - Drosophila model KW - neuronal dysfunction KW - behavior Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-176799 VL - 12 IS - 106 ER - TY - JOUR A1 - Yu, Sung-Huan A1 - Vogel, Jörg A1 - Förstner, Konrad U. T1 - ANNOgesic: a Swiss army knife for the RNA-seq based annotation of bacterial/archaeal genomes JF - GigaScience N2 - To understand the gene regulation of an organism of interest, a comprehensive genome annotation is essential. While some features, such as coding sequences, can be computationally predicted with high accuracy based purely on the genomic sequence, others, such as promoter elements or noncoding RNAs, are harder to detect. RNA sequencing (RNA-seq) has proven to be an efficient method to identify these genomic features and to improve genome annotations. However, processing and integrating RNA-seq data in order to generate high-resolution annotations is challenging, time consuming, and requires numerous steps. We have constructed a powerful and modular tool called ANNOgesic that provides the required analyses and simplifies RNA-seq-based bacterial and archaeal genome annotation. It can integrate data from conventional RNA-seq and differential RNA-seq and predicts and annotates numerous features, including small noncoding RNAs, with high precision. The software is available under an open source license (ISCL) at https://pypi.org/project/ANNOgesic/. KW - genome annotation KW - RNA-seq KW - transcriptomics Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-178942 VL - 7 ER - TY - JOUR A1 - Simon, Micha A1 - Ipek, Rojda A1 - Homola, György A. A1 - Rovituso, Damiano M. A1 - Schampel, Andrea A1 - Kleinschnitz, Christoph A1 - Kuerten, Stefanie T1 - Anti-CD52 antibody treatment depletes B cell aggregates in the central nervous system in a mouse model of multiple sclerosis JF - Journal of Neuroinflammation N2 - Background: Multiple sclerosis (MS) is a chronic autoimmune disease of the central nervous system (CNS) for which several new treatment options were recently introduced. Among them is the monoclonal anti-CD52 antibody alemtuzumab that depletes mainly B cells and T cells in the immune periphery. Considering the ongoing controversy about the involvement of B cells and in particular the formation of B cell aggregates in the brains of progressive MS patients, an in-depth understanding of the effects of anti-CD52 antibody treatment on the B cell compartment in the CNS itself is desirable. Methods: We used myelin basic protein (MBP)-proteolipid protein (PLP)-induced experimental autoimmune encephalomyelitis (EAE) in C57BL/6 (B6) mice as B cell-dependent model of MS. Mice were treated intraperitoneally either at the peak of EAE or at 60 days after onset with 200 μg murine anti-CD52 vs. IgG2a isotype control antibody for five consecutive days. Disease was subsequently monitored for 10 days. The antigen-specific B cell/antibody response was measured by ELISPOT and ELISA. Effects on CNS infiltration and B cell aggregation were determined by immunohistochemistry. Neurodegeneration was evaluated by Luxol Fast Blue, SMI-32, and Olig2/APC staining as well as by electron microscopy and phosphorylated heavy neurofilament serum ELISA. Results: Treatment with anti-CD52 antibody attenuated EAE only when administered at the peak of disease. While there was no effect on the production of MP4-specific IgG, the treatment almost completely depleted CNS infiltrates and B cell aggregates even when given as late as 60 days after onset. On the ultrastructural level, we observed significantly less axonal damage in the spinal cord and cerebellum in chronic EAE after anti-CD52 treatment. Conclusion: Anti-CD52 treatment abrogated B cell infiltration and disrupted existing B cell aggregates in the CNS. KW - Alemtuzumab KW - B cells KW - CD52 KW - CNS KW - EAE KW - MS Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-176120 VL - 15 IS - 225 ER - TY - JOUR A1 - Rieger, C. T. A1 - Liss, B. A1 - Mellinghoff, S. A1 - Buchheidt, D. A1 - Cornely, O. A. A1 - Egerer, G. A1 - Heinz, W. J. A1 - Hentrich, M. A1 - Maschmeyer, G. A1 - Mayer, K. A1 - Sandherr, M. A1 - Silling, G. A1 - Ullmann, A. A1 - Vehreschild, M. J. G. T. A1 - von Lilienfeld-Toal, M. A1 - Wolf, H. H. A1 - Lehners, N. T1 - Anti-infective vaccination strategies in patients with hematologic malignancies or solid tumors-Guideline of the Infectious Diseases Working Party (AGIHO) of the German Society for Hematology and Medical Oncology (DGHO) JF - Annals of Oncology N2 - Infectious complications are a significant cause of morbidity and mortality in patients with malignancies specifically when receiving anticancer treatments. Prevention of infection through vaccines is an important aspect of clinical care of cancer patients. Immunocompromising effects of the underlying disease as well as of antineoplastic therapies need to be considered when devising vaccination strategies. This guideline provides clinical recommendations on vaccine use in cancer patients including autologous stem cell transplant recipients, while allogeneic stem cell transplantation is subject of a separate guideline. The document was prepared by the Infectious Diseases Working Party (AGIHO) of the German Society for Hematology and Medical Oncology (DGHO) by reviewing currently available data and applying evidence-based medicine criteria. KW - infection KW - anti-infective vaccination KW - cancer KW - immunosuppression KW - autologous stem cell transplantation Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-226196 VL - 29 IS - 6 ER - TY - JOUR A1 - Strobel, Lea A1 - Johswich, Kay O. T1 - Anticoagulants impact on innate immune responses and bacterial survival in whole blood models of Neisseria meningitidis infection JF - Scientific Reports N2 - Neisseria meningitidis (meningococcus) causes invasive diseases such as meningitis or septicaemia. Ex vivo infection of human whole blood is a valuable tool to study meningococcal virulence factors and the host innate immune responses. In order to consider effects of cellular mediators, the coagulation cascade must be inhibited to avoid clotting. There is considerable variation in the anticoagulants used among studies of N. meningitidis whole blood infections, featuring citrate, heparin or derivatives of hirudin, a polypeptide from leech saliva. Here, we compare the influence of these three different anticoagulants, and additionally Mg/EGTA, on host innate immune responses as well as on viability of N. meningitidis strains isolated from healthy carriers and disease cases, reflecting different sequence types and capsule phenotypes. We found that the anticoagulants significantly impact on cellular responses and, strain-dependently, also on bacterial survival. Hirudin does not inhibit complement and is therefore superior over the other anticoagulants; indeed hirudin-plasma most closely reflects the characteristics of serum during N. meningitidis infection. We further demonstrate the impact of heparin on complement activation on N. meningitidis and its consequences on meningococcal survival in immune sera, which appears to be independent of the heparin binding antigens Opc and NHBA. KW - infection KW - pathogens KW - Neisseria meningitidis KW - anticoagulants Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-176226 VL - 8 IS - 10225 ER - TY - THES A1 - Skaf, Joseph T1 - Antileishmanial and antitrypanosomal compounds from \(Achillea\) \(fragrantissima\) T1 - Antileishmanien- und Antitrypanosomen-Wirkstoffe aus \(Achillea\) \(fragrantissima\) N2 - This PhD thesis is dealing with the bioassay-guided fractionation of a dichloromethane extract of the aerial parts of Achillea fragrantissima with the aim of isolation and structure isolation of the antileishmanial and/or antitrypanosomal principles in the plant. N2 - Diese Dissertation beschäftigt sich mit der aktivitätsgeleiteten Fraktionierung eines Dichlormethanextrakts aus den oberirdischen Teilen von Achillea fragrantissima mit dem Ziel der Isolierung und Strukturaufklärung der anti-leishmanialen und/oder anti-trypanosomalen Verbindungen der Pflanze. KW - Schafgarbe KW - Antitrypanosomal KW - Antitrypanosomen KW - Flavonoinds KW - Sesquiterpene lactones KW - Alkamides KW - Achillea Fragrantissima KW - Flavoniden KW - Sesquiterpenlactonen KW - Alkamiden KW - Arzneimittelforschung KW - Trypanosomen KW - Leishmania Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-167841 ER - TY - JOUR A1 - Rostás, Michael A1 - Bollmann, Felix A1 - Saville, David A1 - Riedel, Michael T1 - Ants contribute to pollination but not to reproduction in a rare calcareous grassland forb JF - PeerJ N2 - The number of plants pollinated by ants is surprisingly low given the abundance of ants and the fact that they are common visitors of angiosperms. Generally ants are considered as nectar robbers that do not provide pollination service. We studied the pollination system of the endangered dry grassland forb Euphorbia seguieriana and found two ant species to be the most frequent visitors of its flowers. Workers of Formica cunicularia carried five times more pollen than smaller Tapinoma erraticum individuals, but significantly more viable pollen was recovered from the latter. Overall, the viability of pollen on ant cuticles was significantly lower (p < 0.001)-presumably an antibiotic effect of the metapleural gland secretion. A marking experiment suggested that ants were unlikely to facilitate outcrossing as workers repeatedly returned to the same individual plant. In open pollinated plants and when access was given exclusively to flying insects, fruit set was nearly 100%. In plants visited by ants only, roughly one third of flowers set fruit, and almost none set fruit when all insects were excluded. The germination rate of seeds from flowers pollinated by flying insects was 31 +/- 7% in contrast to 1 +/- 1% resulting from ant pollination. We conclude that inbreeding depression may be responsible for the very low germination rate in ant pollinated flowers and that ants, although the most frequent visitors, play a negligible or even deleterious role in the reproduction of E. seguieriana. Our study reiterates the need to investigate plant fitness effects beyond seed set in order to confirm ant-plant mutualisms. KW - Ants KW - Breeding system KW - Geitonogamy KW - Germination KW - Inbreeding depression KW - Metapleural gland KW - Siberian spurge KW - Foraging behaviour KW - Pollen KW - Ecology KW - Entomology Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-227053 VL - 6 ER - TY - JOUR A1 - de Jong, Simone A1 - Diniz, Mateus Jose Abdalla A1 - Saloma, Andiara A1 - Gadelha, Ary A1 - Santoro, Marcos L. A1 - Ota, Vanessa K. A1 - Noto, Cristiano A1 - Curtis, Charles A1 - Newhouse, Stephen J. A1 - Patel, Hamel A1 - Hall, Lynsey S. A1 - O'Reilly, Paul F. A1 - Belangero, Sintia I. A1 - Bressan, Rodrigo A. A1 - Breen, Gerome T1 - Applying polygenic risk scoring for psychiatric disorders to a large family with bipolar disorder and major depressive disorder JF - Communications Biology N2 - Psychiatric disorders are thought to have a complex genetic pathology consisting of interplay of common and rare variation. Traditionally, pedigrees are used to shed light on the latter only, while here we discuss the application of polygenic risk scores to also highlight patterns of common genetic risk. We analyze polygenic risk scores for psychiatric disorders in a large pedigree (n ~ 260) in which 30% of family members suffer from major depressive disorder or bipolar disorder. Studying patterns of assortative mating and anticipation, it appears increased polygenic risk is contributed by affected individuals who married into the family, resulting in an increasing genetic risk over generations. This may explain the observation of anticipation in mood disorders, whereby onset is earlier and the severity increases over the generations of a family. Joint analyses of rare and common variation may be a powerful way to understand the familial genetics of psychiatric disorders. KW - bipolar disorder KW - depression KW - genetic association study KW - genetic linkage study Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-223622 VL - 1 ER - TY - JOUR A1 - Dasari, Prasad A1 - Shopova, Iordana A. A1 - Stroe, Maria A1 - Wartenberg, Dirk A1 - Martin-Dahse, Hans A1 - Beyersdorf, Niklas A1 - Hortschansky, Peter A1 - Dietrich, Stefanie A1 - Cseresnyés, Zoltán A1 - Figge, Marc Thilo A1 - Westermann, Martin A1 - Skerka, Christine A1 - Brakhage, Axel A. A1 - Zipfel, Peter F. T1 - Aspf2 From Aspergillus fumigatus Recruits Human Immune Regulators for Immune Evasion and Cell Damage JF - Frontiers in Immunology N2 - The opportunistic fungal pathogen Aspergillus fumigatus can cause life-threatening infections, particularly in immunocompromised patients. Most pathogenic microbes control host innate immune responses at the earliest time, already before infiltrating host immune cells arrive at the site of infection. Here, we identify Aspf2 as the first A. fumigatus Factor H-binding protein. Aspf2 recruits several human plasma regulators, Factor H, factor-H-like protein 1 (FHL-1), FHR1, and plasminogen. Factor H contacts Aspf2 via two regions located in SCRs6–7 and SCR20. FHL-1 binds via SCRs6–7, and FHR1 via SCRs3–5. Factor H and FHL-1 attached to Aspf2-maintained cofactor activity and assisted in C3b inactivation. A Δaspf2 knockout strain was generated which bound Factor H with 28% and FHL-1 with 42% lower intensity. In agreement with less immune regulator acquisition, when challenged with complement-active normal human serum, Δaspf2 conidia had substantially more C3b (>57%) deposited on their surface. Consequently, Δaspf2 conidia were more efficiently phagocytosed (>20%) and killed (44%) by human neutrophils as wild-type conidia. Furthermore, Aspf2 recruited human plasminogen and, when activated by tissue-type plasminogen activator, newly generated plasmin cleaved the chromogenic substrate S2251 and degraded fibrinogen. Furthermore, plasmin attached to conidia damaged human lung epithelial cells, induced cell retraction, and caused matrix exposure. Thus, Aspf2 is a central immune evasion protein and plasminogen ligand of A. fumigatus. By blocking host innate immune attack and by disrupting human lung epithelial cell layers, Aspf2 assists in early steps of fungal infection and likely allows tissue penetration. KW - complement KW - blocking opsonization KW - phagocytosis KW - acquisition of host regulators KW - immune evasion Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-197013 SN - 1664-3224 VL - 9 IS - 1635 ER - TY - JOUR A1 - Emser, Theresa S. A1 - Johnston, Blair A. A1 - Steele, J. Douglas A1 - Kooij, Sandra A1 - Thorell, Lisa A1 - Christiansen, Hanna T1 - Assessing ADHD symptoms in children and adults: evaluating the role of objective measures JF - Behavioral and Brain Functions N2 - Background: Diagnostic guidelines recommend using a variety of methods to assess and diagnose ADHD. Applying subjective measures always incorporates risks such as informant biases or large differences between ratings obtained from diverse sources. Furthermore, it has been demonstrated that ratings and tests seem to assess somewhat different constructs. The use of objective measures might thus yield valuable information for diagnosing ADHD. This study aims at evaluating the role of objective measures when trying to distinguish between individuals with ADHD and controls. Our sample consisted of children (n = 60) and adults (n = 76) diagnosed with ADHD and matched controls who completed self- and observer ratings as well as objective tasks. Diagnosis was primarily based on clinical interviews. A popular pattern recognition approach, support vector machines, was used to predict the diagnosis. Results: We observed relatively high accuracy of 79% (adults) and 78% (children) applying solely objective measures. Predicting an ADHD diagnosis using both subjective and objective measures exceeded the accuracy of objective measures for both adults (89.5%) and children (86.7%), with the subjective variables proving to be the most relevant. Conclusions: We argue that objective measures are more robust against rater bias and errors inherent in subjective measures and may be more replicable. Considering the high accuracy of objective measures only, we found in our study, we think that they should be incorporated in diagnostic procedures for assessing ADHD. KW - ADHD KW - support vector machines KW - classification KW - objective assessment KW - children/adults Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-175717 VL - 14 IS - 11 ER - TY - JOUR A1 - Rodríguez-Entrena, Macario A1 - Schuberth, Florian A1 - Gelhard, Carsten T1 - Assessing statistical differences between parameters estimates in Partial Least Squares path modeling JF - Quality & Quantity N2 - Structural equation modeling using partial least squares (PLS-SEM) has become a main-stream modeling approach in various disciplines. Nevertheless, prior literature still lacks a practical guidance on how to properly test for differences between parameter estimates. Whereas existing techniques such as parametric and non-parametric approaches in PLS multi-group analysis solely allow to assess differences between parameters that are estimated for different subpopulations, the study at hand introduces a technique that allows to also assess whether two parameter estimates that are derived from the same sample are statistically different. To illustrate this advancement to PLS-SEM, we particularly refer to a reduced version of the well-established technology acceptance model. KW - Testing parameter difference KW - Bootstrap KW - Confidence interval KW - Practitioner's guide KW - Statistical misconception KW - Consistent partial least squares Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-226403 VL - 52 IS - 1 ER - TY - THES A1 - Hebron Mwalwisi, Yonah T1 - Assessment of Counterfeit and Substandard Antimalarial Medicines using High Performance Thin Layer Chromatography and High Performance Liquid Chromatography T1 - Untersuchung der Qualität gefälschter Antimalaria-Medikamente mittels Hochleistungs-Dünnschichtchromatographie und Hochleistungs-Flüssigchromatographie N2 - Although the prevalence of substandard and counterfeit pharmaceutical products is a global problem, it is more critical in resource-constrained countries. The national medicines regulatory authorities (MNRA) in these countries have limited resources to cater for regular quality surveillance programmes aimed at ensuring that medicines in circulation are of acceptable quality. Among the reasons explained to hinder the implementation of these strategies is that compendial monographs are too complicated and require expensive infrastructures in terms of environment, equipment and consumables. In this study it was therefore aimed at developing simple, precise, and robust HPLC and HPTLC methods utilizing inexpensive, readily available chemicals (methanol and simple buffers) that can determine the APIs, other API than declared one, and which are capable of impurity profiling. As an outcome of this study, three isocratic and robust HPLC and two HPTLC methods for sulfadoxine, sulfalene, pyrimethamine, primaquine, artesunate, as well as amodiaquine have been developed and validated. All HPLC methods are operated using an isocratic elution mode which means they can be implemented even with a single pump HPLC system and standard C18 columns. The densitometric sulfadoxine/sulfalene and pyrimethamine method utilizes standard TLC plates as well as inexpensive, readily available and safe chemicals (toluene, methanol, and ethyl acetate), while that for artesunate and amodiaquine requires HPTLC plates as well as triethylamine and acetonitrile due to challenges associated with the analysis of amodiaquine and poorly the detectable artesunate. These HPTLC methods can be implemented as alternative to those requiring HPLC equipment e.g. in countries that already have acquired densitometer equipment. It is understood that HPTLC methods are less sensitive, precise and accurate when compared to HPLC methods, but this hindrance can easily be addressed by sending representative samples to third party quality control laboratories where the analytical results are verified using compendial HPLC methods on a regular basis. It is therefore anticipated that the implementation of these methods will not only address the problem of limited resources required for medicines quality control but also increase the number of monitored targeted antimalarial products as well as the number of resource- constrained countries participating in quality monitoring campaigns. Moreover, the experiences and skills acquired within this work will be applied to other API groups, e. g. antibiotics, afterwards. N2 - Trotz der weltweiten Verbreitung gefälschter Arzneimittel und solcher, die nicht die deklarierte Menge an Wirkstoff enthalten, sind vor allem Entwicklungs- und Schwellenländer von dieser Problematik betroffen. Die Arzneimittelüberwachungs- bzw. Zulassungsbehörden dieser Länder verfügen nur über eingeschränkte Möglichkeiten, die Arzneimittelqualität regelmäßig zu überwachen und somit sicherzustellen, dass die im Markt befindlichen Medikamente eine gute Qualität aufweisen. Einer der Gründe hierfür ist unter anderem, dass die in Arzneibüchern beschriebenen Methoden oftmals sehr komplex sind und eine umfassende Laborausstattung, spezielle Geräte oder teure Chemikalien benötigen. In dieser Arbeit wurden einfache, genaue und robuste flüssigchromatographische Methoden entwickelt, die lediglich günstige, überall verfügbare Chemikalien (z. B. Methanol oder einfache Puffersalze) benötigen und mit denen der Gehalt des deklarierten Arzneistoffes, Arzneistoffverwechslungen sowie das Verunreinigungsprofil bestimmt werden kann. Es konnten drei isokratische, robuste flüssigchromatographische sowie zwei dünnschichtchromatographische Methoden zur Bestimmung von Sulfadoxin, Sulfalen, Pyrimethamin, Primaquin, Artesunat sowie Amodiaquin entwickelt und validiert werden. Alle flüssigchromatographischen Methoden arbeiten isokratisch, folglich können sie auch mit sehr einfachen HPLC-Geräten mit beispielsweise nur einem Pumpenkopf genutzt werden. Zudem werden nur einfache, kommerziell erhältliche C18-Säulen benötigt. Die densitometrischen Methoden für Sulfadoxin/Sulfalen sowie Pyrimethamin benötigen standardisierte Dünnschichtchromatographie-Platten sowie günstige, überall verfügbare und wenig toxische Chemikalien wie beispielsweise Toluol, Methanol oder Ethylacetat. Für die Methode zur Bestimmung von Artesunat und Amodiaquin werden Hochleistungsdünnschichtchromatographie-Platten und Triethylamin sowie Acetonitril benötigt. Dieser Umstand ist der Tatsache geschuldet, dass Amodiaquin und Artesunat sich anderweitig nur ungenügend trennen ließen. Die dünnschichtchromatographischen Protokolle können als Alternative zur HPLC eingesetzt werden, beispielsweise überall dort, wo bereits die entsprechenden Gerätschaften vorhanden sind. Natürlich weisen dünnschichtchromatographische Methoden im Vergleich zur Flüssigchromatographie eine geringere Sensitivität, Präzision und Richtigkeit auf, dies kann jedoch dadurch umgangen werden, die entsprechenden Methoden nur zum Screening zu verwenden und die zu analysierenden Proben anderweitig, z. B. in externen Laboratorien, detailliert zu untersuchen. Dort können beispielsweise Methoden aus gängigen Arzneibüchern verwendet werden. Durch die Implementierung der neu entwickelten Methoden kann zum einen das Problem schlecht verfügbarer Chemikalien umgangen werden und gleichzeitig die Anzahl an untersuchten Arzneimitteln erhöht werden. Dies ist ein wichtiger Beitrag zur Qualitätskontrolle in Ländern mit eingeschränkten Infrastrukturen. KW - Instrumentelle Analytik KW - Arzneimittel KW - Fälschung KW - Malaria KW - HPLC KW - Counterfeit Medicines KW - HPLC KW - Pharmaceutical Analysis KW - Impurity Profiling Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-145821 ER - TY - JOUR A1 - Salinger, Tim A1 - Hu, Kai A1 - Liu, Dan A1 - Taleh, Scharoch A1 - Herrmann, Sebastian A1 - Oder, Daniel A1 - Gensler, Daniel A1 - Müntze, Jonas A1 - Ertl, Georg A1 - Lorenz, Kristina A1 - Frantz, Stefan A1 - Weidemann, Frank A1 - Nordbeck, Peter T1 - Association between Comorbidities and Progression of Transvalvular Pressure Gradients in Patients with Moderate and Severe Aortic Valve Stenosis JF - Cardiology Research and Practice N2 - Background. Fast progression of the transaortic mean gradient (P-mean) is relevant for clinical decision making of valve replacement in patients with moderate and severe aortic stenosis (AS) patients. However, there is currently little knowledge regarding the determinants affecting progression of transvalvular gradient in AS patients. Methods. This monocentric retrospective study included consecutive patients presenting with at least two transthoracic echocardiography examinations covering a time interval of one year or more between April 2006 and February 2016 and diagnosed as moderate or severe aortic stenosis at the final echocardiographic examination. Laboratory parameters, medication, and prevalence of eight known cardiac comorbidities and risk factors (hypertension, diabetes, coronary heart disease, peripheral artery occlusive disease, cerebrovascular disease, renal dysfunction, body mass index >= 30 Kg/m(2), and history of smoking) were analyzed. Patients were divided into slow (P-mean < 5 mmHg/year) or fast (P-mean >= 5 mmHg/year) progression groups. Results. A total of 402 patients (mean age 78 +/- 9.4 years, 58% males) were included in the study. Mean follow-up duration was 3.4 +/- 1.9 years. The average number of cardiac comorbidities and risk factors was 3.1 +/- 1.6. Average number of cardiac comorbidities and risk factors was higher in patients in slow progression group than in fast progression group (3.3 +/- 1.5 vs 2.9 +/- 1.7; P = 0.036). Patients in slow progression group had more often coronary heart disease (49.2% vs 33.6%; P = 0.003) compared to patients in fast progression group. LDL-cholesterol values were lower in the slow progression group (100 +/- 32.6 mg/dl vs 110.8 +/- 36.6 mg/dl; P = 0.005). Conclusion. These findings suggest that disease progression of aortic valve stenosis is faster in patients with fewer cardiac comorbidities and risk factors, especially if they do not have coronary heart disease. Further prospective studies are warranted to investigate the outcome of patients with slow versus fast progression of transvalvular gradient with regards to comorbidities and risk factors. KW - Valvular heart-desease KW - Prognostic impact KW - Risk-factors KW - Chronic heart-failure KW - Prevalence KW - mild KW - statins KW - therapy KW - mortality Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-227291 ER - TY - JOUR A1 - Dittert, Natalie A1 - Hüttner, Sandrina A1 - Polak, Thomas A1 - Herrmann, Martin J. T1 - Augmentation of fear extinction by transcranial direct current stimulation (tDCS) JF - Frontiers in Behavioral Neuroscience N2 - Although posttraumatic stress disorder (PTSD; DSM-V 309.82) and anxiety disorders (DSM-V 300.xx) are widely spread mental disorders, the effectiveness of their therapy is still unsatisfying. Non-invasive brain-stimulation techniques like transcranial direct current stimulation (tDCS) might be an option to improve extinction learning, which is a main functional factor of exposure-based therapy for anxiety disorders. To examine this hypothesis, we used a fear conditioning paradigm with female faces as conditioned stimuli (CS) and a 95-dB female scream as unconditioned stimulus (UCS). We aimed to perform a tDCS of the ventromedial prefrontal cortex (vmPFC), which is mainly involved in the control of extinction-processes. Therefore, we applied two 4 × 4 cm electrodes approximately at the EEG-positions F7 and F8 and used a direct current of 1.5 mA. The 20-min stimulation was started during a 10-min break between acquisition and extinction and went on overall extinction-trials. The healthy participants were randomly assigned in two double-blinded process into two sham stimulation and two verum stimulation groups with opposite current flow directions. To measure the fear reactions, we used skin conductance responses (SCR) and subjective ratings. We performed a generalized estimating equations model for the SCR to assess the impact of tDCS and current flow direction on extinction processes for all subjects that showed a successful conditioning (N = 84). The results indicate that tDCS accelerates early extinction processes with a significantly faster loss of CS+/CS- discrimination. The discrimination loss was driven by a significant decrease in reaction toward the CS+ as well as an increase in reaction toward the CS- in the tDCS verum groups, whereas the sham groups showed no significant reaction changes during this period. Therefore, we assume that tDCS of the vmPFC can be used to enhance early extinction processes successfully. But before it should be tested in a clinical context further investigation is needed to assess the reason for the reaction increase on CS-. If this negative side effect can be avoided, tDCS may be a tool to improve exposure-based anxiety therapies. KW - brain stimulation KW - fear conditioning KW - skin conduction response KW - tDCS KW - ventromedial prefrontal cortex Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-176056 VL - 12 IS - 76 ER - TY - JOUR A1 - Kaltdorf, Kristin Verena A1 - Theiss, Maria A1 - Markert, Sebastian Matthias A1 - Zhen, Mei A1 - Dandekar, Thomas A1 - Stigloher, Christian A1 - Kollmannsberger, Philipp T1 - Automated classification of synaptic vesicles in electron tomograms of C. elegans using machine learning JF - PLoS ONE N2 - Synaptic vesicles (SVs) are a key component of neuronal signaling and fulfil different roles depending on their composition. In electron micrograms of neurites, two types of vesicles can be distinguished by morphological criteria, the classical “clear core” vesicles (CCV) and the typically larger “dense core” vesicles (DCV), with differences in electron density due to their diverse cargos. Compared to CCVs, the precise function of DCVs is less defined. DCVs are known to store neuropeptides, which function as neuronal messengers and modulators [1]. In C. elegans, they play a role in locomotion, dauer formation, egg-laying, and mechano- and chemosensation [2]. Another type of DCVs, also referred to as granulated vesicles, are known to transport Bassoon, Piccolo and further constituents of the presynaptic density in the center of the active zone (AZ), and therefore are important for synaptogenesis [3]. To better understand the role of different types of SVs, we present here a new automated approach to classify vesicles. We combine machine learning with an extension of our previously developed vesicle segmentation workflow, the ImageJ macro 3D ART VeSElecT. With that we reliably distinguish CCVs and DCVs in electron tomograms of C. elegans NMJs using image-based features. Analysis of the underlying ground truth data shows an increased fraction of DCVs as well as a higher mean distance between DCVs and AZs in dauer larvae compared to young adult hermaphrodites. Our machine learning based tools are adaptable and can be applied to study properties of different synaptic vesicle pools in electron tomograms of diverse model organisms. KW - synaptic vesicles KW - Caenorhabditis elegans KW - machine learning Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-176831 VL - 13 IS - 10 ER - TY - JOUR A1 - Dindas, Julian A1 - Scherzer, Sönke A1 - Roelfsema, M. Rob G. A1 - Meyer, Katharina von A1 - Müller, Heike M. A1 - Al-Rasheid, K. A. S. A1 - Palme, Klaus A1 - Dietrich, Petra A1 - Becker, Dirk A1 - Bennett, Malcolm J. A1 - Hedrich, Rainer T1 - AUX1-mediated root hair auxin influx governs SCFTIR1/AFB-type Ca2+ signaling JF - Nature Communications N2 - Auxin is a key regulator of plant growth and development, but the causal relationship between hormone transport and root responses remains unresolved. Here we describe auxin uptake, together with early steps in signaling, in Arabidopsis root hairs. Using intracellular microelectrodes we show membrane depolarization, in response to IAA in a concentration- and pH-dependent manner. This depolarization is strongly impaired in aux1 mutants, indicating that AUX1 is the major transporter for auxin uptake in root hairs. Local intracellular auxin application triggers Ca2+ signals that propagate as long-distance waves between root cells and modulate their auxin responses. AUX1-mediated IAA transport, as well as IAA- triggered calcium signals, are blocked by treatment with the SCFTIR1/AFB - inhibitor auxinole. Further, they are strongly reduced in the tir1afb2afb3 and the cngc14 mutant. Our study reveals that the AUX1 transporter, the SCFTIR1/AFB receptor and the CNGC14 Ca2+ channel, mediate fast auxin signaling in roots. KW - auxin KW - permeation and transport Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-225368 VL - 9 ER - TY - JOUR A1 - Straub, Tobias A1 - Freudenberg, Marina A. A1 - Schleicher, Ulrike A1 - Bogdan, Christian A1 - Gasteiger, Georg A1 - Pircher, Hanspeter T1 - Bacterial coinfection restrains antiviral CD8 T-cell response via LPS-induced inhibitory NK cells JF - Nature Communications N2 - Infection of specific pathogen-free mice with lymphocytic choriomeningitis virus (LCMV) is a widely used model to study antiviral T-cell immunity. Infections in the real world, however, are often accompanied by coinfections with unrelated pathogens. Here we show that in mice, systemic coinfection with E. coli suppresses the LCMV-specific cytotoxic T-lymphocyte (CTL) response and virus elimination in a NK cell- and TLR2/4-dependent manner. Soluble TLR4 ligand LPS also induces NK cell-mediated negative CTL regulation during LCMV infection. NK cells in LPS-treated mice suppress clonal expansion of LCMV-specific CTLs by a NKG2D- or NCR1-independent but perforin-dependent mechanism. These results suggest a TLR4-mediated immunoregulatory role of NK cells during viral-bacterial coinfections. KW - Bacterial infection KW - infection KW - lymphocyte activation KW - viral infection Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-240075 VL - 9 ER - TY - JOUR A1 - Bartmann, Catharina A1 - Janaki Raman, Sudha R. A1 - Flöter, Jessica A1 - Schulze, Almut A1 - Bahlke, Katrin A1 - Willingstorfer, Jana A1 - Strunz, Maria A1 - Wöckel, Achim A1 - Klement, Rainer J. A1 - Kapp, Michaela A1 - Djuzenova, Cholpon S. A1 - Otto, Christoph A1 - Kämmerer, Ulrike T1 - Beta-hydroxybutyrate (3-OHB) can influence the energetic phenotype of breast cancer cells, but does not impact their proliferation and the response to chemotherapy or radiation JF - Cancer & Metabolism N2 - Background: Ketogenic diets (KDs) or short-term fasting are popular trends amongst supportive approaches for cancer patients. Beta-hydroxybutyrate (3-OHB) is the main physiological ketone body, whose concentration can reach plasma levels of 2–6 mM during KDs or fasting. The impact of 3-OHB on the biology of tumor cells described so far is contradictory. Therefore, we investigated the effect of a physiological concentration of 3 mM 3-OHB on metabolism, proliferation, and viability of breast cancer (BC) cells in vitro. Methods: Seven different human BC cell lines (BT20, BT474, HBL100, MCF-7, MDA-MB 231, MDA-MB 468, and T47D) were cultured in medium with 5 mM glucose in the presence of 3 mM 3-OHB at mild hypoxia (5% oxygen) or normoxia (21% oxygen). Metabolic profiling was performed by quantification of the turnover of glucose, lactate, and 3-OHB and by Seahorse metabolic flux analysis. Expression of key enzymes of ketolysis as well as the main monocarboxylic acid transporter MCT2 and the glucose-transporter GLUT1 was analyzed by RT-qPCR and Western blotting. The effect of 3-OHB on short- and long-term cell proliferation as well as chemo- and radiosensitivity were also analyzed. Results: 3-OHB significantly changed the oxygen consumption rate (OCR) and extracellular acidification rate (ECAR) in BT20 cells resulting in a more oxidative energetic phenotype. MCF-7 and MDA-MB 468 cells had increased ECAR only in response to 3-OHB, while the other three cell types remained uninfluenced. All cells expressed MCT2 and GLUT1, thus being able to uptake the metabolites. The consumption of 3-OHB was not strongly linked to mRNA overexpression of key enzymes of ketolysis and did not correlate with lactate production and glucose consumption. Neither 3-OHB nor acetoacetate did interfere with proliferation. Further, 3-OHB incubation did not modify the response of the tested BC cell lines to chemotherapy or radiation. Conclusions: We found that a physiological level of 3-OHB can change the energetic profile of some BC cell lines. However, 3-OHB failed to influence different biologic processes in these cells, e.g., cell proliferation and the response to common breast cancer chemotherapy and radiotherapy. Thus, we have no evidence that 3-OHB generally influences the biology of breast cancer cells in vitro. KW - ketogenic diet KW - β-Hydroxybutyrate KW - ketone bodies KW - breast cancer KW - seahorse KW - metabolic profile KW - chemotherapy KW - ionizing radiation Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-175607 VL - 6 IS - 8 ER - TY - THES A1 - Jones, Gabriel T1 - Bioinspired FGF-2 delivery for pharmaceutical application T1 - Bioinspiriertes Delivery von FGF-2 für eine pharmazeutische Applikation N2 - In resent years the rate of biologics (proteins, cytokines and growth-factors) as newly registered drugs has steadily risen. The greatest challenge for pharmaceutical biologics poses its arrival at the desired target location due to e.g. proteolytic and pH dependent degradation, plasma protein binding, insolubility etc. Therefore, advanced drug delivery systems, where biologics are site directed immobilized to carriers mimicking endogenous storage sites such as the extra cellular matrix can enormously assist the application and consequently the release of exogenous administered pharmaceutical biologics. We have resorted to the fibroblast growth factor 2/ heparansulfate/ fibroblast growth factor bindingprotein 1 system as a model. Phase I deals with the selection and subcloning of a wild type murine FGF-2 construct into the bacterial pHis-Trx vector system for high yields of expression and fast, feasible purification measurements. This first step enables the provision of mFGF-2, which plays a pivotal part as a growth factor in the wound healing process as well as the vascularization of tumors, for future investigations. Therefore, the correct expression of mFGF-2 was monitored via MALDI-MS and SDS-PAGE, whereas the proper folding of the tertiary beta-trefoil structure was assessed by fluorescence spectroscopy. The MTT assay allowed us to ensure that the bioactivity was comparable to sourced FGF-2. In the last step, the purity; a requirement for future binding- and protein-protein interaction assays was monitored chromatographically (RP-HPLC). In addition, a formulation for freeze-drying was developed to ensure protein stability and integrity over a period of 60 days. Altogether, the bacterial expression and purification proved to be suitable, leading to bioactive and stable production of mFGF-2. In Phase II the expression, purification and characterization of FGFBP1, as the other key partner in the FGF-2/ HS/ FGFBP1 system is detailed. As FGFBP1 exhibits a complex tertiary structure, comprised of five highly conserved disulfide bonds and presumably multiple glycosylation sites, a eukaryotic expression was used. Human embryonic kidney cells (HEK 293F) as suspension cells were transiently transfected with DNA-PEI complexes, leading to expression of Fc-tagged murine FGFBP1. Different PEI to DNA ratios and expression durations were investigated for optimal expression yields, which were confirmed by western blot analysis and SDS-PAGE. LC-MS/MS analysis of trypsin and elastase digested FGFBP1 gave first insights of the three O-glycosylation sites. Furthermore, the binding protein was modified by inserting a His6-tag between the Fc-tag (for purification) and the binding protein itself to enable later complexation with radioactive 99mTc as radio ligand to track bio distribution of administered FGFBP1 in mice. Overall, expression, purification and characterization of mFGFBP1 variants were successful with a minor draw back of instability of the tag free binding protein. Combining the insights and results of expressed FGF-2 as well as FGFBP1 directed us to the investigation of the interaction of each partner in the FGF-2/ HS/ FGFBP1 system as Phase III. Thermodynamic behavior of FGF-2 and low molecular weight heparin (enoxaparin), as a surrogate for HS, under physiological conditions (pH 7.4) and pathophysiological conditions, similar to hypoxic, tumorous conditions (acidic pH) were monitored by means of isothermal titration calorimetry. Buffer types, as well as the pH influences binding parameters such as stoichiometry (n), enthalpy (ΔH) and to some extent the dissociation constant (KD). These findings paved the way for kinetic binding investigations, which were performed by surface plasmon resonance assays. For the first time the KD of full length FGFBP1 and FGF-2 was measured. Furthermore the binding behavior of FGF-2 to FGFBP1 in the presence of various heparin concentrations suggest a kinetic driven release of bound FGF-2 by its chaperone FGFBP1. Having gathered multiple data on the FGF-2 /HS /FGFBP1 system mainly in solution, our next step in Phase IV was the development of a test system for immobilized proteins. With the necessity to better understand and monitor the cellular effects of immobilized growth factors, we decorated glass slides in a site-specific manner with an RGD-peptide for adhesion of cells and via the copper(I)-catalyzed-azide-alkyne cycloaddition (CuAAC) a fluorescent dye (a precursor for modified proteins for click chemistry). Human osteosarcoma cells were able to grow an the slides and the fluorescence dye was immobilized in a biocompatible way allowing future thorough bioactivity assay such as MTT-assays and phospho-ERK-assays of immobilized growth factors. N2 - In den letzten Jahren ist der Anteil an Biologika (Proteine, Zytokine und Wachstumsfaktoren), die neu zugelassen wurden, kontinuierlich angestiegen. Die größte Herausforderung für Biopharmazeutika stellt das Erreichen des gewünschten Wirkortes dar, aufgrund von beispielsweise enzymatischen und pH abhängigem Abbau, Plasmaproteinbindung, und niedriger Löslichkeit. Daher können moderne Wirkstoffträgersysteme, in denen Biologika ortsspezifisch an Träger immobilisiert sind und endogene Aufbewahrungsorte nachahmen, wie zum Beispiel die extrazelluläre Matrix, die Anwendung enorm erleichtern und folglich auch die Freisetzung von Biopharmazeutika, die exogen verabreicht wurden ermöglichen. Wir haben uns auf das Fibroblasten-Wachstumsfaktor 2/ Heparansulfat/ Fibroblasten-Wachstumsfaktor Bindungsprotein 1 (FGF-2/ HS/ FGFBP1) System als Modell gestützt. Abschnitt I handelt von der Auswahl und der Subklonierung von einem wildtypischen, murinen FGF-2 Konstrukt in ein bakterielles pHis-Trx Vektorsystem – für hohe Ausbeuten bei der Expression und für eine schnell durchführbare Aufreinigung. Dieser erste Schritt ermöglicht die Bereitstellung von mFGF-2 für zukünftige Untersuchungen, das eine zentrale Rolle als Wachstumsfaktor im Wundheilungsprozess spielt, genauso wie bei der Gefäßversorgung von Tumoren. Daher wurde die richtige Expression von mFGF-2 durch MALDI-MS und SDS-PAGE überwacht, wobei die korrekte Faltung der tertiären beta-Faltblatt-Struktur durch Fluoreszenzmikroskopie ausgewertet wurde. Mit dem MTT Test konnten wir gewährleisten, dass die Bioaktivität von mFGF-2 und dem käuflich erworbenen FGF-2 übereinstimmen. Im letzten Schritt wurde die Reinheit, die eine wichtige Voraussetzung für künftige Bindungs- und Protein-Protein-Wechselwirkung-Untersuchungen darstellt, chromatographisch (RP-HPLC) überwacht. Des Weiteren wurde eine Formulierung zur Gefriertrocknung entwickelt, um die Stabilität und Unversehrtheit des Proteins über 60 Tage sicherzustellen. Insgesamt erwiesen sich die bakterielle Expression und Aufreinigung als geeignet und führten zur Herstellung von bioaktivem und stabilem mFGF-2. Im Abschnitt II wird die Expression, Aufreinigung und Charakterisierung von FGFBP1 genau beschrieben, ein ebenso wichtiger Partner im FGF-2/HS/FGFBP1-System. Da FGFBP1 eine komplexe tertiäre Struktur aufweist, die aus fünf hochkonservierten Disulfidbrücken und vermutlich einigen Glykosylierungsstellen besteht, wurde ein eukaryotisches Expressionssystem angewendet. Menschliche embryonale Nierenzellen (HEK 293F) wurden als Suspensionszellen transient mit DNA-PEI Komplexen transfiziert und führten zur Expression von Fc markiertem mausartigem FGFBP1. Verschiedene PEI:DNA Verhältnisse wurden untersucht, sowie die Dauer der Expression variiert, um die Ausbeute der Expression zu optimieren. Die Ergebnisse wurden mittels Western Blot und SDS-PAGE bestätigt. Die LC-MS/MS Messung, des mit Trypsin und Elastase verdautem FGFBP1, ergaben erste Erkenntnisse über die drei O-Glykosylierungsstellen. Des Weiteren wurde das Fusionsprotein durch Einschub eines His6-tags zwischen den Fc-tag und FGFBP1 erweitert, um dem Protein die Eigenschaft zu geben, mehrwertige Kationen zu komplexieren. 99mTc, als radioaktiver Ligand, kann in späteren Untersuchungen die Verteilung im Gewebe, anhand von Mäusen darstellen. Die Expression, Aufreinigung, sowie die Charakterisierung von den murinen FGFBP1 Varianten war erfolgreich, jedoch erwies sich das Bindungsprotein ohne Fc-Teil als weniger stabil. Durch Zusammenfassung der Ergebnisse und Erkenntnisse der beiden exprimierten Proteine mFGF-2 und FGFBP1, konnten wir die Wechselwirkungen der Partner im FGF-2 /HS / FGFBP1 Systems untereinander im Abschnitt III untersuchen. Isotherme Titrationskalorimetrie wurde herangezogen, um das thermodynamische Verhalten von FGF-2 mit niedermolekularem Heparin (Enoxaparin), als Stellvertreter für HS, unter physiologischen Bedingungen (pH 7,4) und pathologischer Bedingungen (saurer pH, hervorgerufen durch Sauerstoffmangel im Tumorgewebe) aufzuklären. Sowohl die Art des Puffersystems als auch der pH Wert beeinflussen die Bindungsparameter: Enthalpie (DH), die Stöchiometrie (n) und zu einem gewissen Teil sogar die Dissoziationkonstante (KD). Die thermodynamischen Untersuchungen ermöglichten im folgenden Schritt, mittels Oberflächen Plasmon Resonanz (SPR), kinetische Bindungsverhältnisse zu ermitteln. Zum ersten Mal wurde dank der SPR Dissoziationskonstanten von FGFBP1 und FGF-2 erfasst. Da alle bisherigen Erkenntnisse des FGF-2/ HS/ FGFBP1 Systems hauptsächlich von in Lösung gebrachten Partnern gewonnen wurden, erfolgte im Abschnitt IV die Entwicklung eines Testsystems für immobilisierte Proteine. Durch die zwingende Notwendigkeit zelluläre Effekte von immobilisierten Wachstumsfaktoren zu verstehen und zu beobachten, haben wir Objektträger aus Glas, in einem ortsspezifischem Verfahren mit einem RGD-Peptid, für die Zellanhaftung und mittels 1,3-Dipolare Cycloaddition einen Fluoreszenzfarbstoff (ein Vorläufer für „clickbare“, modifizierte Proteine) dekoriert. Menschliche Knochenkrebszellen waren in der Lage auf diesen Objektträgern zu wachsen und der Farbstoff konnte in einem nicht zytotoxischen Verfahren spezifisch an der Oberfläche immobilisiert werden. Dieses Testsystem erlaubt in Zukunft ausführliche Bioaktivitäts- und Proliferationsstudien von immobilisierten Proteinen durchzuführen. KW - Fibroblastenwachstumsfaktor KW - Extrazelluläre Matrix KW - FGF KW - advanced drug delivery system KW - extra cellular matrix Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-153179 ER - TY - JOUR A1 - Soares Machado, J. A1 - Tran-Gia, J. A1 - Schlögl, S. A1 - Buck, A. K. A1 - Lassmann, M. T1 - Biokinetics, dosimetry, and radiation risk in infants after \(^{99m}\)Tc-MAG3 scans JF - EJNMMI Research N2 - Background: Renal scans are among the most frequent exams performed on infants and toddlers. Due to the young age, this patient group can be classified as a high-risk group with a higher probability for developing stochastic radiation effects compared to adults. As there are only limited data on biokinetics and dosimetry in this patient group, the aim of this study was to reassess the dosimetry and the associated radiation risk for infants undergoing \(^{99m}\)Tc-MAG3 renal scans based on a retrospective analysis of existing patient data. Consecutive data were collected from 20 patients younger than 20 months (14 males; 6 females) with normal renal function undergoing \(^{99m}\)Tc-MAG3 scans. To estimate the patient-specific organ activity, a retrospective calibration was performed based on a set of two 3D-printed infant kidneys filled with known activities. Both phantoms were scanned at different positions along the anteroposterior axis inside a water phantom, providing depth- and size-dependent attenuation correction factors for planar imaging. Time-activity curves were determined by drawing kidney, bladder, and whole-body regions-of-interest for each patient, and subsequently applying the calibration factor for conversion of counts to activity. Patient-specific time-integrated activity coefficients were obtained by integrating the organ-specific time-activity curves. Absorbed and effective dose coefficients for each patient were assessed with OLINDA/EXM for the provided newborn and 1-year-old model. The risk estimation was performed individually for each of the 20 patients with the NCI Radiation Risk Assessment Tool. Results: The mean age of the patients was 7.0 ± 4.5 months, with a weight between 5 and 12 kg and a body size between 60 and 89 cm. The injected activities ranged from 12 to 24 MBq of \(^{99m}\)Tc-MAG3. The patients' organ-specific mean absorbed dose coefficients were 0.04 ± 0.03 mGy/MBq for the kidneys and 0.27 ± 0.24 mGy/MBq for the bladder. The mean effective dose coefficient was 0.02 ± 0.02 mSv/MBq. Based on the dosimetry results, an evaluation of the excess lifetime risk for the development of radiation-induced cancer showed that the group of newborns has a risk of 16.8 per 100,000 persons, which is about 12% higher in comparison with the 1-year-old group with 14.7 per 100,000 persons (all values are given as mean plus/minus one standard deviation except otherwise specified). Conclusion: In this study, we retrospectively derived new data on biokinetics and dosimetry for infants with normal kidney function after undergoing renal scans with \(^{99m}\)Tc-MAG3. In addition, we analyzed the associated age- and gender-specific excess lifetime risk due to ionizing radiation. The radiation-associated stochastic risk increases with the organ doses, taking age- and gender-specific influences into account. Overall, the lifetime radiation risk associated with the \(^{99m}\)Tc-MAG3 scans is very low in comparison to the general population risk for developing cancer. KW - \(^{99m}\)Tc-MAG3 KW - absorbed dose KW - biokinetics KW - dosimetry KW - pediatric patients KW - risk assessment Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-175582 VL - 8 IS - 10 ER - TY - THES A1 - Behets, Jean Nicolas T1 - Biomimetic calcium phosphate modification of 3D-printed tissue engineering scaffolds using reactive star-shaped macromers T1 - Biomimetische Calcium-Phosphat Modifikation auf 3D-gedruckten tissue engineering Scaffolds mit reaktiven stern-förmigen Makromeren N2 - Biomimetic calcium phosphate (CaP) coatings imitate the trabecular bones surface structure and have shown to promote osteogenic differentiation in multipotent cells. The work of this thesis focused on the problem of former CaP coatings cracking and flaking off when being put on a bendable core structure like a 3D-printed poly (ε-caprolactone) (PCL) scaffold. The aim was to provide a chemical linkage between PCL and CaP using a star-shaped polymer (sPEG) and a phosphonate, 2-aminoethylphosphonic acid (2-AEP). First, a published CaP coating protocol was revised and investigated in terms of etching parameters for the PCL scaffold. Results presented reproducible thick coatings for all groups. The protocol was then broadened to include subsequent scaffold incubation in sPEG and 2-AEP solutions. Homogenous CaP coatings of decreased thickness presented themselves, proving feasibility. However, as is often found with physical CaP coating depositions, there were some irregular outcomes even during the same experimental group. A lower consumption of the chemical 2-AEP, for economic reasons, meant that the protocol was altered to simultaneously incubate scaffolds with sPEG and 2-AEP including preceding calculations for molar ratios. For ratios 1:1, 1:2 and 1:3, again a homogenous CaP coating was produced on most of the samples, although reproducibility issues maintained. However, the mechanical bending to induce surface cracking showed that the CaP did strongly bond to the sPEG/2-AEP, while the control CaP coating flaked off the surface in large pieces. This research demonstrates that chemically-bound CaP coatings resist flaking off the fiber surface. Future investigations should focus on the mechanisms of CaP crystallization, to improve reproducibility. N2 - Biomimetische Calciumphosphat (CaP) - Beschichtungen imitieren die oberflächliche Struktur des spongiösen Knochens und wirkten sich bereits begünstigend auf die osteogene Differenzierung von multipotenten Zellen aus. Diese Dissertation konzentriert sich auf das Problem des Reißens und Abplatzens bisheriger CaP-Beschichtungen, wenn diese sich auf einem biegsamen Kern-Gerüst, wie einem 3D-gedruckten Polycaprolacton (PCL)-Konstrukt befanden. Das Ziel war, durch den Gebrauch eines sternförmigen Polymers (sPEG) und eines Phosphonates, 2-Aminoethylphosphonsäure (2-AEP), eine chemische Verknüpfung zwischen PCL und CaP herzustellen. Zuerst wurde ein bereits publiziertes CaP-Beschichtungs-Protokoll nachgestellt und verschiedene Ätzungsparameter untersucht. Die Ergebnisse zeigten reproduzierbare, dicke Beschichtungen in allen Gruppen. Danach wurde dieses Protokoll erweitert, indem es nun nacheinander gestellte Inkubationen in sPEG- und 2-AEP-Lösungen mit einbezog. Dünnere, homogene Beschichtungen waren das Ergebnis, was beweist, dass die Hypothese realisierbar ist. Jedoch zeigten die Ergebnisse nicht reproduzierbare Resultate. Desweiteren, war der 2-AEP Verbrauch nicht wirtschaftlich. Daher wurde das Protokoll weiterentwickelt, indem die Proben, nach vorherigen Berechnungen zu den molaren Verhältnissen, simultan mit sPEG und 2-AEP inkubiert wurden. Für die Verhältnisse 1:1, 1:2 und 1:3 wurden wiederum homogene CaP-Beschichtungen produziert. Mit der Absicht Reproduzierbarkeit zu erzielen, wurden weitere Parameter untersucht. Dies blieb jedoch erfolglos. Zuletzt wurde ein mechanischer Test durchgeführt, welcher eine verbesserte CaP-Adhäsion zu den PCL-Fasern nahelegt, wenn diese zuvor mit sPEG und 2-AEP inkubiert wurden. Zukünftige Untersuchungen werden jedoch von Nöten sein, um Daten zur Oberflächenanalyse und von weiteren mechanischen Tests bereitzustellen und um das Protokoll in Bezug auf die Reproduzierbarkeit zu verbessern. KW - Tissue engineering KW - Calcium phosphate KW - Melt electrospinning KW - Star-shaped poly(ethylene glycol) KW - 2-Aminoethylphosphonic acid Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-171728 ER - TY - THES A1 - Braun, Alexandra Carolin T1 - Bioresponsive delivery of anticatabolic and anabolic agents for muscle regeneration using bioinspired strategies T1 - Bioresponsive Verabreichung anti-kataboler und anaboler Wirkstoffe zur Muskelregeneration unter Verwendung bioinspirierter Strategien N2 - Progressive loss of skeletal muscle mass, strength and function poses a major threat to independence and quality of life, particularly in the elderly. To date, sarcopenia therapy consists of resistance exercise training in combination with protein supplementation due to the limited efficacy of available pharmacological options in counteracting the effects of muscle wasting. Therapeutic intervention with growth factors including insulin-like growth factor I (IGF-I) or inhibitors of myostatin  a potent suppressor of myogenesis  hold potential to rebalance the altered activity of anabolic and catabolic cytokines. However, dosing limitations due to acute side effects and disruptions of the homeostasis have so far precluded clinical application. Intending to provide a therapy with a superior safety and efficacy profile by directing drug release to inflamed tissue and minimizing off-target activity, we designed bioresponsive delivery systems for an anti-catabolic peptide and anabolic IGF-I responding to local flares of muscle wasting. In Chapter I, current concepts for bioorthogonal conjugation methods are discussed and evaluated based on various drug delivery applications. With a focus on protein delivery, challenges and potential pitfalls of each chemical and enzymatic conjugation strategy are analyzed and opportunities regarding their use for coupling of biomolecules are given. Based on various studies conjugating proteins to polymers, particles and biomaterials using different site-directed approaches, the chapter summarizes available strategies and highlights certain aspects requiring particular consideration when applied to biomolecules. Finally, a decision process for selection of an optimum conjugation strategy is exemplarily presented. Three of these bioorthogonal coupling reactions are applied in Chapter II detailing the potential of site-directed conjugation in the development of novel, homogenous drug delivery systems. The chapter describes the design of a delivery system of a myostatin inhibitor (MI) for controlled and local release counteracting myositis flares. MI release from the carrier is driven by increased matrix metalloproteinase (MMP) levels in compromised muscle tissues cleaving the interposed linker, thereby releasing the peptide inhibitor from the particulate carrier. Release experiments were performed to assess the response towards various MMP isoforms (MMP-1, -8, -9 and -13) – as upregulated during skeletal muscle myopathies – and the release pattern of the MI in case of disease progression was analyzed. By selection of the protease-sensitive linker (PSL) showing variable susceptibilities to proteases, release rates of the MI can be controlled and adapted. Immobilized MI as well as released MI as response to MMP upregulation was able to antagonize the effects of myostatin on cell signalling and myoblast differentiation. The approach of designing bioresponsive protein delivery systems was also applied to the anabolic growth factor IGF-I, as described in Chapter III. Numerous studies of PEGylated proteins or peptides reveal, that successful therapy is challenged by safety and efficacy issues, as polymer attachment considerably alters the properties of the biologic, thereby jeopardizing clinical efficacy. To this end, a novel promising approach is presented, intending to exploit beneficial effects of PEGylation on pharmacokinetics, but addressing the pharmacodynamic challenges by releasing the protein upon entering the target tissue. This was realized by integration of a PSL between the PEG moiety and the protein. The soluble polymer conjugate was produced by site-directed, enzymatic conjugation of IGF-I to the PSL, followed by attachment of a 30 kDa-PEG using Strain-promoted azide-alkyne cycloaddition (SPAAC). This strategy illustrates the potential of bioorthogonal conjugation (as described in Chapter I) for generation of homogenous protein-polymer conjugates with reproducible outcome, but also emphasizes the altered protein properties resulting from permanent polymer conjugation. As compared to wild type IGF-I, the PEGylated protein showed considerable changes in pharmacologic effects – such as impaired insulin-like growth factor binding protein (IGFBPs) interactions, submaximal proliferative activity and altered endocytosis patterns. In contrast, IGF-I characteristics were fully restored upon local disintegration of the conjugate triggered by MMP upregulation and release of the natural growth factor. For successful formulation development for the proteins and conjugates, the careful selection of suitable excipients is crucial for a safe and reliable therapy. Chapter IV addresses one aspect by highlighting the chemical heterogeneity of excipients and associated differences in performance. Polysorbate 80 (PS80) is a surfactant frequently used in protein formulations to prevent aggregation and surface adsorption. Despite being widely deployed as a standard excipient, heterogeneous composition and performance entails the risk of eliciting degradation and adverse effects on protein stability. Based on a comprehensive study using different batches of various suppliers, the PS80 products were characterized regarding chemical composition and physicochemical properties, facilitating the assessment of excipient performance in a formulation. Noticeable deviations were recorded between different suppliers as well as between batches of the same suppliers. Correlation of all parameters revealed, that functionality related characteristics (FRCs) could be reliably predicted based on chemical composition alone or by a combination of chemical and physicochemical properties, respectively. In summary, this thesis describes and evaluates novel strategies for the targeted delivery and controlled release of biologics intended to counteract the imbalance of anabolic and catabolic proteins observed during aging and musculoskeletal diseases. Two delivery platforms were developed and characterized in vitro – (i) using anti-catabolic peptides immobilized on a carrier for local delivery and (ii) using soluble IGF-I polymer conjugates for systemic application. Both approaches were implemented by bioorthogonal coupling strategies, which were carefully selected in consideration of limitations, side reactions and efficiency aspects. Bioresponsive release of the active biomolecules following increased protease activity could be successfully realized. The therapeutic potential of these approaches was demonstrated using various cell-based potency assays. The systems allow targeted and controlled release of the growth factor IGF-I and anti-catabolic peptides thereby overcoming safety concerns of current growth factor therapy and thus positively impacting the benefit-risk profile of potent therapeutics. Taking potential heterogeneity and by-product concerns into account, comprehensive excipient characterization was performed and a predictive algorithm for FRCs developed, in order to facilitate formulation design and guarantee a safe and efficient therapy from start to finish. N2 - Der zunehmende Verlust an Skelettmuskelmasse, Kraft und Funktion stellt insbesondere bei Älteren eine wesentliche Gefährdung der Unabhängigkeit und Lebensqualität dar. Bislang besteht die Sarkopenie-Therapie infolge der eingeschränkten Wirksamkeit verfügbarer pharmakologischer Möglichkeiten, den Auswirkungen des Muskelschwunds entgegenzuwirken, aus einer Kombination von Krafttraining und erhöhter Proteinzufuhr. Therapeutische Intervention mit Wachstumsfaktoren wie Insulin-like growth factor (IGF-I) oder Inhibitoren von Myostatin – eines wirkungsvollen Hemmstoffes der Myogenese – bietet das Potenzial, die veränderte Aktivität der anabolen und katabolen Zytokine wieder ins Gleichgewicht zu bringen. Allerding haben Dosiseinschränkungen aufgrund akuter Nebenwirkungen und Beeinträchtigungen der Homöostase bislang eine klinische Anwendung ausgeschlossen. Mit der Absicht, eine Therapie mit besserem Sicherheits- und Wirksamkeitsprofil zu bieten, indem die Freisetzung des Wirkstoffs auf entzündetes Gewebe gelenkt wird und Aktivitäten außerhalb des Zielgewebes minimiert werden, entwickelten wir bioresponsive Freisetzungssysteme für ein antikataboles Peptid und das anabole IGF-I, die auf lokalen Ausbruch von Muskelschwund reagieren. In Kapitel I werden aktuelle Konzepte bioorthogonaler Konjugationsmethoden diskutiert und auf Basis einer Vielzahl von Drug Delivery Anwendungen beurteilt. Mit besonderem Fokus auf die Verabreichung von Proteinen werden Herausforderungen und Schwierigkeiten jeder chemischen und enzymatischen Konjugationsstrategie analysiert und Möglichkeiten im Hinblick auf ihre Verwendung für die Kopplung von Biomolekülen aufgezeigt. Auf Grundlage diverser Studien zur Verknüpfung von Proteinen mit Polymeren, Partikeln und Biomaterialien unter Verwendung verschiedener ortsspezifischer Ansätze, fasst das Kapitel vorhandene Strategien zusammen und hebt gewisse Aspekte hervor, die bei Anwendung auf Biomoleküle besondere Beachtung erfordern. Abschließend wird ein Entscheidungsprozess zur Auswahl einer optimalen Verknüpfungsstrategie exemplarisch dargestellt. Drei dieser bioorthogonalen Kopplungsreaktionen werden in Kapitel II angewendet, wodurch das Potenzial der ortsgerichteten Konjugation für die Entwicklung neuer, homogener Drug Delivery Systeme detailliert aufgezeigt wird. Dieses Kapitel beschreibt die Gestaltung eines Delivery Systems für einen Myostatin- Inhibitor (MI) für kontrollierte und lokale Freisetzung, um Myositis-Ausbrüchen entgegenzuwirken. Die Freisetzung des MI vom Träger wird durch erhöhte Konzentration an Matrix-Metalloproteinasen (MMPs) in betroffenem Muskelgewebe vorangetrieben, die durch Spaltung des dazwischen positionierten Linkers das Peptid vom Partikelträger freisetzen. Es wurden Freisetzungsexperimente durchgeführt, um die Reaktion gegenüber mehreren MMP-Isoformen (MMP-1, -8, -9 und -13), die im Verlauf von Skelettmuskelmyopathien hochreguliert sind, festzustellen, und es wurde das Freisetzungsmuster des MI im Falle einer Krankheitsprogression analysiert. Durch Auswahl der Protease-sensitiven Linker (PSL), die unterschiedliche Empfindlichkeit gegenüber Proteasen zeigen, können die Freisetzungsraten des MI kontrolliert und angepasst werden. Sowohl der immobilisierte MI, als auch der auf MMP-Hochregulation hin freigesetzte MI, waren dazu in der Lage, die Wirkungen von Myostatin auf Signaltransduktion von Zellen und Myoblastendifferenzierung aufzuheben. Das Konzept, bioresponsive Delivery Systeme für Proteine zu designen, wurde auch auf den anabolen Wachstumsfaktor IGF-I angewendet, wie in Kapitel III beschrieben wird. Zahlreiche Studien zu PEGylierten Proteinen oder Peptiden offenbaren, dass eine erfolgreiche Therapie durch Sicherheits- und Wirksamkeitsprobleme herausgefordert wird, da der Polymeranhang die Eigenschaften des biologischen Wirkstoffs beachtlich verändern und dadurch die klinische Wirksamkeit gefährden kann. Zu diesem Zweck wird ein neuer, vielversprechender Ansatz vorgestellt, mit der Absicht, die vorteilhaften Auswirkungen der PEGylierung auf die Pharmakokinetik zu nutzen, aber auch die pharmakodynamischen Herausforderungen dadurch zu adressieren, dass das Protein bei Eintritt ins Zielgewebe freigesetzt wird. Das wurde durch Einfügen eines PSL zwischen den PEG-Teil und das Protein erreicht. Das lösliche Polymerkonjugat wurde durch ortsspezifische, enzymatische Konjugation von IGF-I an den PSL hergestellt, gefolgt von Verknüpfung mit einem 30k Da-PEG unter Verwendung von kupferfreier Azid-Alkin Cycloaddition (SPAAC). Diese Strategie veranschaulicht das Potenzial der bioorthogonalen Konjugation (wie in Kapitel I beschrieben) zur Erzeugung homogener Protein-Polymer-Konjugate mit reproduzierbarem Ergebnis, aber betont auch die veränderten Proteineigenschaften, die sich aus der dauerhaften Polymerkonjugation ergeben. Verglichen mit dem Wildtyp-IGF-I zeigte das PEGylierte Protein beachtliche Veränderungen der pharmakologischen Eigenschaften, wie verminderte Interaktionen mit Insulin-like growth factor Bindungsproteinen (IGFBPs), eine submaximale proliferative Aktivität und ein verändertes Endozytosemuster. Im Gegensatz dazu wurden die Eigenschaften von IGF-I bei lokaler Spaltung des Konjugates durch MMP-Hochregulation und Freisetzung des natürlichen Wachstumsfaktors vollständig wiederhergestellt. Für eine erfolgreiche Formulierungsentwicklung der Proteine und Konjugate ist eine sorgfältige Auswahl geeigneter Hilfsstoffe für eine sichere und zuverlässige Therapie essenziell. Kapitel IV befasst sich mit einem Aspekt davon, indem die chemische Heterogenität von Hilfsstoffen und damit verbundene Unterschiede in der Leistung hervorgehoben werden. Polysorbat 80 (PS80) ist ein in Proteinformulierungen häufig verwendeter Hilfsstoff, der Aggregation und Oberflächenadsorption verhindern soll. Trotz dieser breiten Anwendung als Standardhilfsstoff birgt die heterogene Zusammensetzung und Performance Risiken, wie eine begünstigte Zersetzung und nachteilige Auswirkungen auf die Proteinstabilität. Auf Basis einer umfassenden Studie mit verschiedenen Chargen diverser Anbieter wurden die PS80 Produkte hinsichtlich ihrer chemischen Zusammensetzung und ihrer physikochemischen Eigenschaften charakterisiert, um eine Beurteilung der Hilfsstoffperformance in einer Formulierung zu ermöglichen. Auffällige Abweichungen sowohl zwischen unterschiedlichen Anbietern, also auch zwischen Chargen des gleichen Anbieters konnten verzeichnet werden. Die Korrelation aller Parameter ergab, dass funktionalitätsbezogene Eigenschaften (FRCs) auf Basis der chemischen Zusammensetzung alleine bzw. durch eine Kombination aus chemischen und physikochemischen Eigenschaften zuverlässig prognostiziert werden konnten. Zusammenfassend beschreibt und bewertet diese Dissertation neue Strategien für eine zielgerichtete und kontrollierte Freisetzung von biologischen Wirkstoffen mit der Absicht, dem Ungleichgewicht zwischen anabolen und katabolen Proteinen, welches im Laufe der Alterung und im Zuge muskuloskelettaler Erkrankungen beobachtet wird, entgegenzuwirken. Zwei Wirkstoff-Verabreichungsplattformen wurden entwickelt und in vitro charakterisiert: (i) unter Verwendung antikataboler Peptide, die für eine lokale Applikation auf einem Träger immobilisiert werden, und (ii) unter Verwendung löslicher IGF-I-Polymer Konjugate für die systemische Anwendung. Beide Ansätze wurden mittels bioorthogonaler Kopplungsstrategien, die unter Berücksichtigung von Einschränkungen, Nebenreaktionen und Effizienzaspekten sorgfältig ausgewählt wurden, durchgeführt. Die bioresponsive Freisetzung der aktiven Biomoleküle als Folge einer erhöhten Proteaseaktivität konnte erfolgreich umgesetzt werden. Das therapeutische Potenzial dieser Ansätze wurde anhand mehrerer zellbasierter Wirksamkeitsassays gezeigt. Die Systeme ermöglichen eine zielgerichtete und kontrollierte Freisetzung des Wachstumsfaktors IGF-I und antikataboler Peptide, wobei sie die Sicherheitsbedenken aktueller Wachstumsfaktortherapie bewältigen und somit das Nutzen-Risiko-Profil hochwirksamer Therapeutika positiv beeinflussen. Unter Berücksichtigung der potenziellen Bedenken bezüglich Heterogenität und Nebenprodukten wurde eine umfassende Hilfsstoffcharakterisierung durchgeführt und ein prognostischer Algorithmus für FRCs entwickelt, um die Formulierungsentwicklung zu erleichtern und eine sichere und effiziente Therapie von Anfang bis zum Ende zu garantieren. KW - Muskelatrophie KW - Kontrollierte Wirkstofffreisetzung KW - Insulin-like Growth Factor KW - Myositis KW - bioresponsive KW - protease-sensitive release KW - co-delivery Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-169047 ER - TY - JOUR A1 - Pfitzner, Christian A1 - May, Stefan A1 - Nüchter, Andreas T1 - Body weight estimation for dose-finding and health monitoring of lying, standing and walking patients based on RGB-D data JF - Sensors N2 - This paper describes the estimation of the body weight of a person in front of an RGB-D camera. A survey of different methods for body weight estimation based on depth sensors is given. First, an estimation of people standing in front of a camera is presented. Second, an approach based on a stream of depth images is used to obtain the body weight of a person walking towards a sensor. The algorithm first extracts features from a point cloud and forwards them to an artificial neural network (ANN) to obtain an estimation of body weight. Besides the algorithm for the estimation, this paper further presents an open-access dataset based on measurements from a trauma room in a hospital as well as data from visitors of a public event. In total, the dataset contains 439 measurements. The article illustrates the efficiency of the approach with experiments with persons lying down in a hospital, standing persons, and walking persons. Applicable scenarios for the presented algorithm are body weight-related dosing of emergency patients. KW - RGB-D KW - human body weight KW - image processing KW - kinect KW - machine learning KW - perception KW - segmentation KW - sensor fusion KW - stroke KW - thermal camera Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-176642 VL - 18 IS - 5 ER - TY - JOUR A1 - Scheer, Ulrich T1 - Boveri's research at the Zoological Station Naples: Rediscovery of his original microscope slides at the University of Würzburg JF - Marine Genomics N2 - Eric Davidson once wrote about Theodor Boveri: "From his own researches, and perhaps most important, his generalized interpretations, derive the paradigms that underlie modern inquiries into the genomic basis of embryogenesis" (Davidson, 1985). As luck would have it, the "primary data" of Boveri's experimental work, namely the microscope slides prepared by him and his wife Marcella during several stays at the Zoological Station in Naples (1901/02, 1911/12 and 1914), have survived at the University of Wurzburg. More than 600 slides exist and despite their age they are in a surprisingly good condition. The slides are labelled and dated in Boveri's handwriting and thus can be assigned to his published experimental work on sea urchin development. The results allowed Boveri to unravel the role of the cell nucleus and its chromosomes in development and inheritance. Here, I present an overview of the slides in the context of Boveri's work along with photographic images of selected specimens taken from the original slides. It is planned to examine the slides in more detail, take high-resolution focal image series of significant specimens and make them online available. KW - Sea urchin development KW - Polyspermy KW - Multipolar mitosis KW - Aneuploidy KW - Merogone experiments KW - Science history Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-228453 VL - 40 ER - TY - JOUR A1 - Grimm, Johannes A1 - Hufnagel, Anita A1 - Wobser, Marion A1 - Borst, Andreas A1 - Haferkamp, Sebastian A1 - Houben, Roland A1 - Meierjohann, Svenja T1 - BRAF inhibition causes resilience of melanoma cell lines by inducing the secretion of FGF1 JF - Oncogenesis N2 - Approximately half of all melanoma patients harbour activating mutations in the serine/threonine kinase BRAF. This is the basis for one of the main treatment strategies for this tumor type, the targeted therapy with BRAF and MEK inhibitors. While the initial responsiveness to these drugs is high, resistance develops after several months, frequently at sites of the previously responding tumor. This indicates that tumor response is incomplete and that a certain tumor fraction survives even in drug-sensitive patients, e.g., in a therapy-induced senescence-like state. Here, we show in several melanoma cell lines that BRAF inhibition induces a secretome with stimulating effect on fibroblasts and naive melanoma cells. Several senescence-associated factors were found to be transcribed and secreted in response to BRAF or MEK inhibition, among them members of the fibroblast growth factor family. We identified the growth factor FGF1 as mediator of resilience towards BRAF inhibition, which limits the pro-apoptotic effects of the drug and activates fibroblasts to secrete HGF. FGF1 regulation was mediated by the PI3K pathway and by FRA1, a direct target gene of the MAPK pathway. When FGFR inhibitors were applied in parallel to BRAF inhibitors, resilience was broken, thus providing a rationale for combined therapeutical application. KW - melanoma KW - senescence KW - BRAF KW - tumor Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-177261 VL - 7 IS - 71 ER - TY - THES A1 - Weidner, Magdalena Theodora T1 - Brain serotonin throughout development - for better and for worse T1 - Der Effekt von Serotonin im sich entwickelnden Gehirn - in guten wie in schlechten Tagen N2 - The work presented in this thesis covers the effects of early-life adversity in the context of altered serotonin (5-HT; 5-hydroxytryptamine) system functioning in mice. The main body is focussing on a screening approach identifying molecular processes, potentially involved in distinct behavioural manifestations that emerge from or are concomitant with early adversity and, with regard to some behavioural manifestations, dependent on the functioning of the 5-HT system. N2 - Diese Arbeit berichtet Ergebnisse der umfassenden Erforschung des Einflusses von aversiven Bedingungen während der pränatalen und frühkindlichen Entwicklungsphase, unter dem Einfluss genetischer Variationen des serotonergen (5-HT, 5-Hydroxytryptamin) Systems, im Mausmodel. Der Hauptfokus der Thesis lag bei der hypothesenfreien Untersuchung der Konsequenzen, die durch den kombinierten Effekt aversiver Bedingungen, und genetischer Prädisposition ausgelöst werden, sowie, final, der Ermittlung potentieller Kandidatengene, die an der Manifestierung verhaltensbezogener Konsequenzen beteiligt sein können sowie durch epigenetische Mechanismen reguliert werden. KW - Gehirn KW - Serotonin KW - Entwicklung KW - Stress KW - epigenetics KW - early-life stress KW - rodent model KW - behaviour Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-163345 SN - 978-94-6233-940-8 N1 - This document is also published by the University library Maastricht. Maastricht University holds the same rights as University of Würzburg PB - Magdalena T. Weidner CY - Maastricht, the Netherlands ER - TY - THES A1 - Botrel, Loic T1 - Brain-computer interfaces (BCIs) based on sensorimotor rhythms - Evaluating practical interventions to improve their performance and reduce BCI inefficiency T1 - Gehirn-Computer Schnittstellen (BCIs) basierend auf sensomotorischen Rhythmen - Evaluation praktischer Interventionen zur Verbesserung ihrer Leistung und Reduktion von BCI Ineffizienz N2 - Brain computer interfaces based on sensorimotor rhythms modulation (SMR-BCIs) allow people to emit commands to an interface by imagining right hand, left hand or feet movements. The neurophysiological activation associated with those specific mental imageries can be measured by electroencephalography and detected by machine learning algorithms. Improvements for SMR-BCI accuracy in the last 30 years seem to have reached a limit. The currrent main issue with SMR-BCIs is that between 15% to 30% cannot use the BCI, called the "BCI inefficiency" issue. Alternatively to hardware and software improvements, investigating the individual characteristics of the BCI users has became an interesting approach to overcome BCI inefficiency. In this dissertation, I reviewed existing literature concerning the individual sources of variation in SMR-BCI accuracy and identified generic individual characteristics. In the empirical investigation, attention and motor dexterity predictors for SMR-BCI performance were implemented into a trainings that would manipulate those predictors and lead to higher SMR-BCI accuracy. Those predictors were identified by Hammer et al. (2012) as the ability to concentrate (associated with relaxation levels) and "mean error duration" in a two-hand visuo-motor coordination task (VMC). Prior to a SMR-BCI session, a total of n=154 participants in two locations took part of 23 min sessions of either Jacobson’s Progressive Muscle Relaxation session (PMR), a VMC session, or a control group (CG). No effect of PMR or VMC manipulation was found, but the manipulation checks did not consistently confirm whether PMR had an effect of relaxation levels and VMC on "mean error duration". In this first study, correlations between relaxation levels or "mean error duration" and accuracy were found but not in both locations. A second study, involving n=39 participants intensified the training in four sessions on four consecutive days or either PMR, VMC or CG. The effect or manipulation was assessed for in terms of a causal relationship by using a PRE-POST study design. The manipulation checks of this second study validated the positive effect of training on both relaxation and "mean error duration". But the manipulation did not yield a specific effect on BCI accuracy. The predictors were not found again, displaying the instability of relaxation levels and "mean error duration" in being associated with BCI performance. An effect of time on BCI accuracy was found, and a correlation between State Mindfulness Scale and accuracy were reported. Results indicated that a short training of PMR or VMC were insufficient in increasing SMR-BCI accuracy. This study contrasted with studies succeeding in increasing SMR-BCI accuracy Tan et al. (2009, 2014), by the shortness of its training and the relaxation training that did not include mindfulness. It also contrasted by its manipulation checks and its comprehensive experimental approach that attempted to replicate existing predictors or correlates for SMR-BCI accuracy. The prediction of BCI accuracy by individual characteristics is receiving increased attention, but requires replication studies and a comprehensive approach, to contribute to the growing base of evidence of predictors for SMR-BCI accuracy. While short PMR and VMC trainings could not yield an effect on BCI performance, mindfulness meditation training might be beneficial for SMR-BCI accuracy. Moreover, it could be implemented for people in the locked-in-syndrome, allowing to reach the end-users that are the most in need for improvements in BCI performance. N2 - Les interfaces cerveau-ordinateur (angl. brain-computer interfaces, BCIs) basées sur les rythmes sensorimoteurs (angl. sensorimotor rhythms, SMR) permettent d’émettre des commandes par l’imagination de mouvements des mains ou des jambes. Dans le cas des BCIs non-invasifs, les manifestations neurophysiologiques liées á l’imagination motrice peuvent être mesurées par électroencephalographie (EEG) á la surface du cuir chevelu, puis détectées á l’aide d’algorithmes d’apprentissage. Après 30 années de progrès dans l’implémentation des BCI basées sur les SMR, il devient de plus en plus difficile d’obtenir un gain significatif de performance, alors qu’il est estimé qu’entre 15% et 30 % des utilisateurs ne peuvent pas utiliser une BCI basée sur les SMR. On parle d’inefficacité de la BCI (angl. BCI inefficiency). Une alternative aux avancées matérielles et logicielles réside dans l’investigation de caractéristiques propres à l’utilisateur. Dans ce travail de thèse, j’ai d’abord procédé à une revue de littérature sur les sources individuelles de variation de la performance SMR-BCIs, sous la forme de caractéristiques psychologiques, neurologiques et neuroanatomiques propres à l’utilisateur. Pour l’étude empirique, je me suis basé sur deux prédicteurs – l’attention et la dextérite motrice – que j’ai expérimentalement manipulés par des protocoles d’intervention. Ces deux prédicteurs ont été identifiés par Hammer et al. (2012) en tant que capacité à se concentrer (ability to concentrate) et durée moyenne d’erreur dans une tâche de coordination visuo-motrice (mean error duration in a visuomotor coordination task, VMC). La première étude comprend N=154 participants recrutés dans deux villes allemandes (Würzburg et Berlin). Avant de procéder à une session de BCI basée sur les SMR, les participants ont été aléatoirement répartis en trois groupes d’intervention d’une durée de 23 minutes. Le groupe PMR a pris part à une session de relaxation musculaire progressive de Jacobson, censée relaxer le participant ; le groupe VMC a pris part a une session de coordination visuo-motrice des deux mains, censé augmenter la dextérité motrice ; le groupe controle CG ayant eu pour tâche de lire un texte. Les résultats, analysés indépendemment pour chaque lieu de mesure, indiquent que l’entraînement PMR ou VMC n’ont pas provoqué d’amélioration significative de la performance BCI. L’effet des interventions sur leurs variables témoins respectives (PMR sur le niveau subjectif de relaxation ; VMC sur la durée moyenne d’erreur) sont inéquivoques. Il n’est donc pas possible d’interpréter l’absence d’effet d’entraînement sur la performance BCI. Les corrélations entre les variables témoins et la performance BCI répliquent les deux prédicteurs à l’origine de l’étude, mais ces résultats sont restreints à l’un des deux lieux de mesure. La seconde étude a été menée sur N=39 participants pour lesquels la durée d’entraînement (soit PMR, VMC ou CG) a été prolongée sur quatre sessions étalées sur quatre jours successifs. Cette seconde étude a été conçue selon un modèle pré-test post-test permettant de réduire la sensibilité aux variations inter-individuelles de la performance, ainsi que de tester la présence d’une relation causale entre entraînement et performance BCI. Les variables témoins – relaxation et durée d’erreur VMC– ont evolué de maniere positive validant les entraînements. Cependant, les entraînements PMR et VMC n’ont eu aucun effet positif sur la performance BCI basée sur les SMR. Les prédicteurs n’ont donc pas de nouveau été répliqués, démontrant l’instabilité des niveaux de relaxation et la performance VMC dans leur association avec la performance BCI. L’effet de temps sur la performance BCI, constaté dans de nombreuses études a été répliqué. De manière plus inattendue, une correlation entre l’échelle d’attention consciente (state mindfulness scale, SMS) et la performance BCI a été révélée. Globalement, Les résultats de ces deux études empiriques indiquent que de courts entraînements PMR ou VMC ont été insuffisants pour améliorer la performance BCI. Ces études contrastent donc avec les précédentes études qui au contraîre ont montré un effect positif d’un entraînement en relaxation Tan et al. (2009, 2014), notamment marqués par leur durée s’étalant sur plusieurs mois ainsi que leur forme de relaxations basées sur la méditation de pleine conscience (angl. Mindfulness). Mes deux études se démarquent cependant par la présence de tests de manipulation, l’approche expérimentale basée sur l’implémentation du potentiel des prédicteurs et corrélats de la performance BCI. La prédiction de performance SMR-BCI par des caractérisiques individuelles reçevant une attention croissante ces dernières années, il est nécessaire pour contribuer efficacement au domaine des sources de variation des BCI, d’opter pour une approche expériementale englobant les résultats existants, notamment par l’effort de réplication, et de comparaison d’études. En conclusion, Alors que de courts entraînements PMR et VMC n’ont pas eu d’effets sur la performance BCI basée sur les SMR, la piste de l’entraînement de méditation pleine conscience présente un potentiel qu’il est nécessaire de confirmer. De plus, il pourraît être mis en place pour des patients paralysés moteur (angl. locked-in syndrome, LIS), permettant de fait d’atteîndre la population pouvant le plus profiter des améliorations de la performance BCI. N2 - Gehirn-Computer Schnittstellen (engl. brain-computer interfaces, BCIs), basierend auf der Modulation sensomotorischer Rhythmen (SMR), erlauben Menschen, Befehle an eine Schnittstelle zu übermitteln, beispielsweise durch die Vorstellung von Bewegungen der Hände oder der Füße. Die neurophysiologische Aktivität, die mit den Bewegungsvorstellungen assoziiert ist, kann mittels Elektroenzephalographie gemessen und durch Algorithmen aus dem Bereich des maschinellen Lernens detektiert werden. Die Fortschritte in Bezug auf SMR-BCIs, die es in den letzten 30 Jahren gab, scheinen an eine Grenze zu stoßen. Das Hauptproblem liegt darin, dass 15 bis 30% der Nutzer keine Kontrolle über SMR-BCIs erlangen. Dieses Phänomen wird als „BCI Ineffizienz“ bezeichnet. Neben Verbesserungen der Hard- und Software ist die Untersuchung individueller Charakteristika der BCI Nutzer ein vielversprechender Ansatz, um die BCI Ineffizienz zu überwinden. Im Rahmen dieser Dissertation habe ich zunächst durch eine Literaturstudie zu den Ursachen der Variation der SMR-BCI Genauigkeiten individuelle Charakteristika identifiziert. In der experimentellen Untersuchung wurden Aufmerksamkeit und Feinmotorik als Prädiktoren für die Leistung mit einem SMR-BCI in ein Trainingsparadigma aufgenommen, das zum Ziel hatte, die SMR-BCI Genauigkeiten zu verbessern. Diese Prädiktoren wurden von Hammer et al. (2012) als die Konzentrationsfähigkeit (assoziiert mit Entspannungsniveau) und „mittlere Fehlerdauer“ in einer beidhändigen visuomotorischen Koordinationsaufgabe (engl. two-hand visuo-motor coordination task, VMC) identifiziert. In der ersten Studie der vorliegenden Dissertation nahmen insgesamt n=154 Studienteilnehmer an zwei verschiedenen Standorten teil. Im Vorfeld einer SMR-BCI Sitzung nahmen diese entweder an einer 23-minütigen Sitzung mit Progressiver Muskelrelaxation nach Jacobson (PMR), einer Sitzung mit VMC oder einer Kontrollgruppe (KG) teil. Es zeigten sich keine Effekte auf die Genauigkeiten des SMRBCI als Folge der Versuchsbedingung (VMC, PMR oder KG). Jedoch konnte auch durch Manipulationschecks nicht konsistent bestätigt werden, dass PMR eine Auswirkung auf das Entspannungsniveau und VMC auf die „mittlere Fehlerdauer“ hatte. In dieser ersten Studie konnten Korrelationen zwischen dem Entspannungsniveau oder „mittlerer Fehlerdauer“ und der Genauigkeit mit dem SMR-BCI aufgedeckt werden, jedoch nicht an beiden Standorten. In der zweiten Studie dieser Dissertation mit n=39 Teilnehmern wurde das Training durch die Steigerung auf vier Sitzungen intensiviert, die an vier aufeinanderfolgenden Tagen entweder mit PMR, VMC oder KG durchgeführt wurden. Der Effekt dieser Manipulation auf SMRBCI Genauigkeiten wurde mittels eines Pretest-Posttest-Studiendesigns untersucht. Die Manipulationschecks validierten den positiven Effekt des Trainings sowohl für Entspannung als auch die „mittlere Fehlerdauer“. Es gab jedoch keine spezifische Wirkung des Trainings auf die BCI Genauigkeiten. Entspannungsniveau und „mittlere Fehlerdauer“ konnten nicht als zuverlässige Prädiktoren für SMR-BCI Leistung bestätigt werden. Es gab einen Effekt der Zeit auf die BCI Genauigkeit und eine Korrelation zwischen der State Mindfulness Scale und der Genauigkeit. Die Ergebnisse deuten darauf hin, dass ein kurzes PMR oder VMC Training nicht ausreichten, um SMR-BCI Genauigkeiten zu steigern. Diese Studie steht im Widerspruch zu Studien von Tan et al. (2009, 2014), die erfolgreich die SMR-BCI Genauigkeit steigern konnten, unterscheidet sich von diesen jedoch auch durch die kürzere Trainingsdauer und dem Fehlen von Achtsamkeitskomponenten beim Entspannungstraining. Weitere Unterschiede liegen in dem verwendeten Manipulationscheck und dem umfassenden experimentellen Ansatz der aktuellen Studie mit dem Ziel, zuvor ermittelte Prädiktoren oder Korrelate von SMR-BCI Genauigkeit zu replizieren. Die Vorhersage von BCI Genauigkeit durch individuelle Charakteristika erhält steigende wissenschaftliche Aufmerksamkeit, bedarf aber Replikationsstudien und eines umfassenden Ansatzes, um die Beweislage hinsichtlich Prädiktoren für SMR-BCI Genauigkeit zu verbessern. Während für kurze PMR und VMC Trainings kein Effekt auf die SMR-BCI Genauigkeit aufgedeckt werden konnte, könnte sich achtsamkeitsbasiertes Meditationstraining als vorteilhaft für die Leistung mit einem SMR-BCI erweisen. Darüber hinaus könnte es auch für Personen mit Locked-In-Syndrom implementiert werden, um so diejenigen Endnutzer zu erreichen, die am meisten von Verbesserungen der BCI Leistung profitieren würden. KW - Gehirn-Computer-Schnittstelle KW - Locked-in-Syndrom KW - Intervention KW - Sensorimotor Rhythms KW - visuomotor coordination KW - predictor analysis KW - Psychologie KW - Progressive Relaxation Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-168110 ER - TY - JOUR A1 - Weber-Lassalle, Nana A1 - Hauke, Jan A1 - Ramser, Juliane A1 - Richters, Lisa A1 - Groß, Eva A1 - Blümcke, Britta A1 - Gehrig, Andrea A1 - Kahlert, Anne-Karin A1 - Müller, Clemens R. A1 - Hackmann, Karl A1 - Honisch, Ellen A1 - Weber-Lassalle, Konstantin A1 - Niederacher, Dieter A1 - Borde, Julika A1 - Thiele, Holger A1 - Ernst, Corinna A1 - Altmüller, Janine A1 - Neidhardt, Guido A1 - Nürnberg, Peter A1 - Klaschik, Kristina A1 - Schroeder, Christopher A1 - Platzer, Konrad A1 - Volk, Alexander E. A1 - Wang-Gohrke, Shan A1 - Just, Walter A1 - Auber, Bernd A1 - Kubisch, Christian A1 - Schmidt, Gunnar A1 - Horvath, Judit A1 - Wappenschmidt, Barbara A1 - Engel, Christoph A1 - Arnold, Norbert A1 - Dworniczak, Bernd A1 - Rhiem, Kerstin A1 - Meindl, Alfons A1 - Schmutzler, Rita K. A1 - Hahnen, Eric T1 - BRIP1 loss-of-function mutations confer high risk for familial ovarian cancer, but not familial breast cancer JF - Breast Cancer Research N2 - Background Germline mutations in the BRIP1 gene have been described as conferring a moderate risk for ovarian cancer (OC), while the role of BRIP1 in breast cancer (BC) pathogenesis remains controversial. Methods To assess the role of deleterious BRIP1 germline mutations in BC/OC predisposition, 6341 well-characterized index patients with BC, 706 index patients with OC, and 2189 geographically matched female controls were screened for loss-of-function (LoF) mutations and potentially damaging missense variants. All index patients met the inclusion criteria of the German Consortium for Hereditary Breast and Ovarian Cancer for germline testing and tested negative for pathogenic BRCA1/2 variants. Results BRIP1 LoF mutations confer a high OC risk in familial index patients (odds ratio (OR) = 20.97, 95% confidence interval (CI) = 12.02–36.57, P < 0.0001) and in the subgroup of index patients with late-onset OC (OR = 29.91, 95% CI = 14.99–59.66, P < 0.0001). No significant association of BRIP1 LoF mutations with familial BC was observed (OR = 1.81 95% CI = 1.00–3.30, P = 0.0623). In the subgroup of familial BC index patients without a family history of OC there was also no apparent association (OR = 1.42, 95% CI = 0.70–2.90, P = 0.3030). In 1027 familial BC index patients with a family history of OC, the BRIP1 mutation prevalence was significantly higher than that observed in controls (OR = 3.59, 95% CI = 1.43–9.01; P = 0.0168). Based on the negative association between BRIP1 LoF mutations and familial BC in the absence of an OC family history, we conclude that the elevated mutation prevalence in the latter cohort was driven by the occurrence of OC in these families. Compared with controls, predicted damaging rare missense variants were significantly more prevalent in OC (P = 0.0014) but not in BC (P = 0.0693) patients. Conclusions To avoid ambiguous results, studies aimed at assessing the impact of candidate predisposition gene mutations on BC risk might differentiate between BC index patients with an OC family history and those without. In familial cases, we suggest that BRIP1 is a high-risk gene for late-onset OC but not a BC predisposition gene, though minor effects cannot be excluded. KW - breast cancer KW - ovarian cancer KW - BRIP1 gene KW - germline mutations Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-233433 VL - 20 ER - TY - INPR A1 - Auerhammer, Dominic A1 - Arrowsmith, Merle A1 - Böhnke, Julian A1 - Braunschweig, Holger A1 - Dewhurst, Rian D. A1 - Kupfer, Thomas T1 - Brothers from Another Mother: a Borylene and its Dimer are Non-Interconvertible but Connected through Reactivity T2 - Chemical Science N2 - The self-stabilizing, tetrameric cyanoborylene [(cAAC)B(CN)]4 (I, cAAC = 1-(2,6-diisopropylphenyl)-3,3,5,5-tetramethylpyrrolidin-2-ylidene) and its diborene relative, [(cAAC)(CN)B=B(CN)(cAAC)] (II), both react with disulfides and diselenides to yield the corresponding cAAC-supported cyanoboron bis(chalcogenides). Furthermore, reactions of I or II with elemental sulfur and selenium in various stoichiometries provided access to a variety of cAAC- stabilized cyanoboron-chalcogen heterocycles, including a unique dithiaborirane, a diboraselenirane, 1,3-dichalcogena-2,4-diboretanes, 1,3,4-trichalcogena- 2,5-diborolanes and a rare six-membered 1,2,4,5-tetrathia-3,6-diborinane. Stepwise addition reactions and solution stability studies provided insights into the mechanism of these reactions and the subtle differences in reactivity observed between I and II. KW - borylenes KW - diborenes KW - boron KW - carbenes KW - chalcogens Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-157125 ER - TY - THES A1 - Halboth, Florian T1 - Building behavior and nest climate control in leaf-cutting ants: How environmental cues affect the building responses of workers of \(Atta\) \(vollenweideri\) T1 - Bauverhalten und Kontrolle des Nestklimas bei Blattschneiderameisen: Wie Umweltreize die Bauaktivität von Arbeiterinnen der Art \(Atta\) \(vollenweideri\) beeinflussen N2 - The present work investigates the influence of environmental stimuli on the building behavior of workers of the leaf-cutting ant Atta vollenweideri. It focuses on cues related to the airflow-driven ventilation of their giant underground nests, i.e., air movements and their direction, carbon dioxide concentrations and humidity levels of the nest air. First, it is shown that workers are able to use airflow and its direction as learned orientation cue by performing learning experiments with individual foragers using a classical conditioning paradigm. This ability is expected to allow workers to also navigate inside the nest tunnels using the prevailing airflow directions for orientation, for example during tasks related to nest construction and climate control. Furthermore, the influence of carbon dioxide on the digging behavior of workers is investigated. While elevated CO2 levels hardly affect the digging rate of the ants, workers prefer to excavate at locations with lower concentrations and avoid higher CO2 levels when given a choice. Under natural conditions, shifting their digging activity to soil layers containing lower carbon dioxide levels might help colonies to excavate new or to broaden existing nest openings, if the CO2 concentration in the underground rises. It is also shown that workers preferably transport excavated soil along tunnels containing high CO2 concentrations, when carbon dioxide levels in the underground are elevated as well. In addition, workers prefer to carry soil pellets along outflow tunnels instead of inflow tunnels, at least for high humidity levels of the air. The material transported along tunnels providing outflow of CO2-rich air might be used by workers for the construction of ventilation turrets on top of the nest mound, which is expected to promote the wind-induced ventilation and the removal of carbon dioxide from the underground. The climatic conditions inside the nest tunnels also influence the structural features of the turrets constructed by workers on top the nest. While airflow and humidity have no effect on turret structure, outflow of CO2-rich air from the nest causes workers to construct turrets with additional openings and increased aperture, potentially enhancing the airflow-driven gas exchanges within the nest. Finally, the effect of airflow and ventilation turrets on the gas exchanges in Atta vollenweideri nests is tested experimentally on a physical model of a small nest consisting of a single chamber and two nest tunnels. The carbon dioxide clearance rate from the underground was measured depending on both the presence of airflow in the nest and the structural features of the built turrets. Carbon dioxide is removed faster from the physical nest model when air moves through the nest, confirming the contribution of wind-induced flow inside the nest tunnels to the ventilation of Atta vollenweideri nests. In addition, turrets placed on top of one of the tunnel openings of the nest further enhance the CO2 clearance rate and the effect is positively correlated with turret aperture. Taken together, climatic variables like airflow, carbon dioxide and humidity levels strongly affect the building responses of Atta vollenweideri leaf-cutting ants. Workers use these environmental stimuli as orientation cue in the nest during tasks related to excavation, soil transport and turret construction. Although the effects of these building responses on the microclimatic conditions inside the nest remain elusive so far, the described behaviors are expected to allow ant colonies to restore and maintain a proper nest climate in the underground. N2 - Die vorliegende Arbeit untersucht den Einfluss von Umweltreizen auf das Bauverhalten von Blattschneiderameisen der Art Atta vollenweideri. Dabei wird der Fokus auf Luftströmungen und deren Richtung, sowie CO2-Konzentration und Feuchtigkeitsgehalt der Luft gelegt, welche alle im Zusammenhang mit dem wind-induzierten Ventilationssystem der riesigen, unterirdischen Nester stehen. Zunächst wird experimentell mit Hilfe von klassischer Konditionierung gezeigt, dass Arbeiterinnen während des Furagierens lernen können, Luftströmungen sowie deren Richtung zur Orientierung zu nutzen. Diese Fähigkeit sollte Arbeiterinnen auch die Navigation im Nest anhand der auftretenden Strömungsrichtung der Luft, zum Beispiel während Tätigkeiten im Kontext des Nestbaus und der Klimakontrolle, ermöglichen. Weiterhin wird der Einfluss von Kohlenstoffdioxid auf das Grabeverhalten von Arbeiterinnen untersucht. Obwohl CO2 kaum die Grabe-Rate der Ameisen beeinflusst, graben Arbeiterinnen bevorzugt an Orten mit niedrigerer Konzentration und vermeiden höhere Konzentrationen, wenn möglich. Unter natürlichen Bedingungen könnte das Verlagern der Grabeaktivität in Bodenschichten mit niedrigerer CO2-Konzentration Kolonien dabei helfen, neue Nestöffnungen zu graben oder bestehende zu erweitern, wenn die CO2-Konzentration unter der Erde zunimmt. Zusätzlich wird gezeigt, dass Arbeiterinnen ausgegrabene Erde vornehmlich entlang Tunnel transportieren, die eine hohe CO2-Konzentration aufweisen, wenn die CO2-Konzentration im Untergrund ebenfalls erhöht ist. Zudem bevorzugen Arbeiterinnen den Transport von Erdmaterial entlang Ausstrom- anstatt Einstrom-Tunnel, zumindest für hohe Luftfeuchtigkeiten. Material, welches entlang Nesttunnel transportiert wird, aus denen CO2-haltige Luft ausströmt, könnte Arbeiterinnen zum Bau der Ventilationstürme an der Nestoberfläche dienen, was die wind-induzierte Belüftung der Nester verstärken und die Abfuhr von CO2 aus dem Nest fördern sollte. Die klimatischen Bedingungen in den Nesttunneln beeinflussen auch die strukturellen Eigenschaften der Ventilationstürme, die von Arbeiterinnen oberhalb des Nests errichtet werden. Während Luftströmungen und Luftfeuchtigkeit keinen Einfluss auf die Struktur der Türme haben, veranlasst das Ausströmen von CO2-haltiger Luft aus dem Nest Arbeiterinnen dazu, Türme zu bauen, die mehrere Öffnungen und eine vergrößerte Öffnungsfläche besitzen, was den strömungsinduzierten Gasaustausch im Nest begünstigen könnte. Abschließend werden die Auswirkungen von Luftströmungen und Ventilationstürmen auf den Gasaustausch in den Nestern der Blattschneiderameise Atta vollenweideri mit Hilfe eines physikalischen Modells eines kleinen Nests, bestehend aus einer einzelnen Nestkammer und zwei Nesttunneln, untersucht. Die Abfuhr-Rate von CO2 aus dem Untergrund wurde abhängig vom Vorhandensein von Luftströmungen und den strukturellen Eigenschaften der errichteten Ventilationstürme gemessen. CO2 wird schneller aus dem physikalischen Modell entfernt, wenn Luft durch das Nest strömt, was den Beitrag von Luftbewegungen in den Tunneln zur Ventilation der Nester von Atta vollenweideri bestätigt. Ventilationstürme an einer der Nestöffnungen platziert, verstärken zusätzlich die Abfuhr-Rate von CO2 aus dem Nest und dieser Effekt nimmt mit zunehmender Öffnungsfläche der Türme zu. Zusammengefasst beeinflussen Klimavariablen wie Luftströmungen, Kohlenstoffdioxid und Luftfeuchtigkeit stark das Bauverhalten von Blattschneiderameisen der Art Atta vollenweideri. Arbeiterinnen nutzen diese Umweltreize zur Orientierung im Nest während Tätigkeiten, die im Zusammenhang mit Grabeverhalten, dem Transport von Erdmaterial und dem Bau von Ventilationstürmen stehen. Obwohl die Auswirkungen dieser Bauantworten auf die mikroklimatischen Bedingungen im Nest zunächst noch unklar sind, wird angenommen, dass die beschriebenen Verhaltensweisen es Kolonien erlauben, ein geeignetes Nestklima wiederherzustellen und aufrechtzuerhalten. KW - Verhalten KW - Ameisen KW - Nestbau KW - Klima KW - Kohlendioxid KW - building behavior KW - leaf-cutting ants KW - nest climate KW - climate control KW - carbon dioxide KW - airflow KW - Atta vollenweideri Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-161701 ER - TY - JOUR A1 - Langenhorst, Daniela A1 - Haack, Stephanie A1 - Göb, Selina A1 - Uri, Anna A1 - Lühder, Fred A1 - Vanhove, Bernhard A1 - Hünig, Thomas A1 - Beyersdorf, Niklas T1 - CD28 costimulation of T helper 1 cells enhances cytokine release in vivo JF - Frontiers in Immunology N2 - Compared to naive T cells, differentiated T cells are thought to be less dependent on CD28 costimulation for full activation. To revisit the role of CD28 costimulation in mouse T cell recall responses, we adoptively transferred in vitro generated OT-II T helper (Th) 1 cells into C57BL/6 mice (Thy1.2\(^{+}\)) and then either blocked CD28–ligand interactions with Fab fragments of the anti-CD28 monoclonal antibody (mAb) E18 or deleted CD28 expression using inducible CD28 knock-out OT-II mice as T cell donors. After injection of ovalbumin protein in adjuvant into the recipient mice we observed that systemic interferon (IFN)γ release strongly depended on CD28 costimulation of the Th1 cells, while secondary clonal expansion was not reduced in the absence of CD28 costimulation. For human memory CD4\(^{+}\) T cell responses we also noted that cytokine release was reduced upon inhibition of CD28 costimulation. Together, our data highlight the so far underestimated role of CD28 costimulation for the reactivation of fully differentiated CD4\(^{+}\) T cells. KW - CD4\(^{+}\) T helper cells KW - T helper 1 cells KW - antigenic recall KW - CD28 costimulation KW - cytokine secretion KW - mouse KW - human Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-176726 VL - 9 IS - 1060 ER - TY - JOUR A1 - Rauert-Wunderlich, Hilka A1 - Berberich, Ingolf A1 - Rosenwald, Andreas A1 - Rudelius, Martina T1 - CD40L mediated alternative NF kappa B-signaling induces resistance to BCR-inhibitors in patients with mantle cell lymphoma JF - Cell Death & Disease N2 - Drug resistance is a significant obstacle in cancer treatment and therefore a frequent subject of research. Developed or primary resistance limits the treatment success of inhibitors of the B cell receptor (BCR) pathway in mantle cell lymphoma (MCL) patients. Recent research has highlighted the role of the nuclear factor-kappa B (NF kappa B) pathway in the context of resistance to BCR inhibitors in MCL. In this study, we analyzed the dependency of MCL cell lines on NF kappa B signaling and illustrated the ability of CD40L to activate the alternative NF kappa B pathway in MCL. This activation leads to independency of classical NF kappa B signaling and results in resistance to BCR inhibitors. Therefore, ligands (such as CD40L) and their activation of the alternative NF kappa B pathway have a major impact on the drug response in MCL. Furthermore, this study indicates a protective role for cells expressing specific ligands as microenvironmental niches for MCL cells and underlines the significance of therapeutically targeting alternative NF kappa B signaling in MCL. KW - Bruton Tyrosine Kinase KW - Tumor Microenvironment KW - Targeted Therapies KW - Ibrutinib KW - Pathway KW - Malignancies KW - Activation KW - Ligand KW - Proliferation KW - PCI-32765 Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-225027 IS - 9 ER - TY - JOUR A1 - Zeiner, P. S. A1 - Zinke, J. A1 - Kowalewski, D. J. A1 - Bernatz, S. A1 - Tichy, J. A1 - Ronellenfitsch, M. W. A1 - Thorsen, F. A1 - Berger, A. A1 - Forster, M. T. A1 - Muller, A. A1 - Steinbach, J. P. A1 - Beschorner, R. A1 - Wischhusen, J. A1 - Kvasnicka, H. M. A1 - Plate, K. H. A1 - Stefanović, S. A1 - Weide, B. A1 - Mittelbronn, M. A1 - Harter, P. N. T1 - CD74 regulates complexity of tumor cell HLA class II peptidome in brain metastasis and is a positive prognostic marker for patient survival JF - Acta Neuropathologica Communications N2 - Abstract Despite multidisciplinary local and systemic therapeutic approaches, the prognosis for most patients with brain metastases is still dismal. The role of adaptive and innate anti-tumor response including the Human Leukocyte Antigen (HLA) machinery of antigen presentation is still unclear. We present data on the HLA class II-chaperone molecule CD74 in brain metastases and its impact on the HLA peptidome complexity. We analyzed CD74 and HLA class II expression on tumor cells in a subset of 236 human brain metastases, primary tumors and peripheral metastases of different entities in association with clinical data including overall survival. Additionally, we assessed whole DNA methylome profiles including CD74 promoter methylation and differential methylation in 21 brain metastases. We analyzed the effects of a siRNA mediated CD74 knockdown on HLA-expression and HLA peptidome composition in a brain metastatic melanoma cell line. We observed that CD74 expression on tumor cells is a strong positive prognostic marker in brain metastasis patients and positively associated with tumor-infiltrating T-lymphocytes (TILs). Whole DNA methylome analysis suggested that CD74 tumor cell expression might be regulated epigenetically via CD74 promoter methylation. CD74\(^{high}\) and TIL\(^{high}\) tumors displayed a differential DNA methylation pattern with highest enrichment scores for antigen processing and presentation. Furthermore, CD74 knockdown in vitro lead to a reduction of HLA class II peptidome complexity, while HLA class I peptidome remained unaffected. In summary, our results demonstrate that a functional HLA class II processing machinery in brain metastatic tumor cells, reflected by a high expression of CD74 and a complex tumor cell HLA peptidome, seems to be crucial for better patient prognosis. KW - CD74 KW - HLA class II KW - brain metastasis KW - HLA peptidome KW - tumor infiltrating lymphocytes Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-233882 VL - 6 ER - TY - JOUR A1 - Leicht, Hans Benno A1 - Weinig, Elke A1 - Mayer, Beate A1 - Viebahn, Johannes A1 - Geier, Andreas A1 - Rau, Monika T1 - Ceftriaxone-induced hemolytic anemia with severe renal failure: a case report and review of literature JF - BMC Pharmacology and Toxicology N2 - Background: Drug induced immune hemolytic anemia (DIIHA) is a rare complication and often underdiagnosed. DIIHA is frequently associated with a bad outcome, including organ failure and even death. For the last decades, ceftriaxone has been one of the most common drugs causing DIIHA, and ceftriaxone-induced immune hemolytic anemia (IHA) has especially been reported to cause severe complications and fatal outcomes. Case Presentation: A 76-year-old male patient was treated with ceftriaxone for cholangitis. Short time after antibiotic exposure the patient was referred to intensive care unit due to cardiopulmonary instability. Hemolysis was observed on laboratory testing and the patient developed severe renal failure with a need for hemodialysis for 2 weeks. Medical history revealed that the patient had been previously exposed to ceftriaxone less than 3 weeks before with subsequent hemolytic reaction. Further causes for hemolytic anemia were excluded and drug-induced immune hemolytic (DIIHA) anemia to ceftriaxone could be confirmed. Conclusions: The case demonstrates the severity of ceftriaxone-induced immune hemolytic anemia, a rare, but immediately life-threatening condition of a frequently used antibiotic in clinical practice. Early and correct diagnosis of DIIHA is crucial, as immediate withdrawal of the causative drug is essential for the patient prognosis. Thus, awareness for this complication must be raised among treating physicians. KW - ceftriaxone KW - drug-induced immune hemolytic anemia KW - hemolysis Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-176637 VL - 19 IS - 67 ER - TY - JOUR A1 - Hennrich, Marco L. A1 - Romanov, Natalie A1 - Horn, Patrick A1 - Jaeger, Samira A1 - Eckstein, Volker A1 - Steeples, Violetta A1 - Ye, Fei A1 - Ding, Ximing A1 - Poisa-Beiro, Laura A1 - Mang, Ching Lai A1 - Lang, Benjamin A1 - Boultwood, Jacqueline A1 - Luft, Thomas A1 - Zaugg, Judith B. A1 - Pellagatti, Andrea A1 - Bork, Peer A1 - Aloy, Patrick A1 - Gavin, Anne-Claude A1 - Ho, Anthony D. T1 - Cell-specific proteome analyses of human bone marrow reveal molecular features of age-dependent functional decline JF - Nature Communications N2 - Diminishing potential to replace damaged tissues is a hallmark for ageing of somatic stem cells, but the mechanisms remain elusive. Here, we present proteome-wide atlases of age-associated alterations in human haematopoietic stem and progenitor cells (HPCs) and five other cell populations that constitute the bone marrow niche. For each, the abundance of a large fraction of the ~12,000 proteins identified is assessed in 59 human subjects from different ages. As the HPCs become older, pathways in central carbon metabolism exhibit features reminiscent of the Warburg effect, where glycolytic intermediates are rerouted towards anabolism. Simultaneously, altered abundance of early regulators of HPC differentiation reveals a reduced functionality and a bias towards myeloid differentiation. Ageing causes alterations in the bone marrow niche too, and diminishes the functionality of the pathways involved in HPC homing. The data represent a valuable resource for further analyses, and for validation of knowledge gained from animal models. KW - ageing KW - haematopoietic stem cells KW - mesenchymal stem cells Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-319877 VL - 9 ER - TY - THES A1 - Lorenz, Viola T1 - Cellular regulation of the hemITAM-coupled platelet receptor C-type lectin-like receptor 2 (CLEC-2): In vitro and in vivo studies in mice T1 - Zelluläre Regulation des hemITAM-gekoppelten Thrombozytenrezeptors C-type lectin-like receptor 2 (CLEC-2): In vitro und in vivo Studien in Mäusen N2 - Platelet aggregation at sites of vascular injury is essential to limit posttraumatic blood loss, but may also cause acute ischemic disease states such as myocardial infarction or stroke. Stable thrombus formation requires a series of molecular events involving platelet receptors and intracellular signal transduction, which contribute to adhesion, activation and aggregation of platelets. In this thesis, the cellular regulation of platelet surface receptors and their involvement in thrombus formation was investigated using genetically modified mice. In the first part of the study, the functional relevance of the immunoreceptor tyrosine-based activation motif (ITAM)-coupled collagen receptor GPVI and of the recently identified hemITAM-bearing C-type lectin-like receptor 2 (CLEC-2) for in vivo thrombus formation was analyzed. Megakaryocyte/ platelet-specific CLEC-2 knock out mice displayed a defective lymphatic development and were protected from occlusive arterial thrombus formation. These phenotypes were more pronounced in mice with a GPVI/CLEC-2 double deficiency. Hemostasis was not compromised in CLEC-2 or GPVI single-deficient animals, as they showed only mildly prolonged tail bleeding times. Combined depletion of both receptors resulted in markedly prolonged bleeding times revealing an unexpected redundant function of the two receptors in hemostasis as well as thrombosis. These findings might have important implications for the development of anti-CLEC-2/ anti-GPVI agents as therapeutics. In the second part, mechanisms underlying the cellular regulation of CLEC-2 were studied. Previous studies have shown that injection of the anti-CLEC-2 antibody INU1 results in complete immunodepletion of platelet CLEC-2 in mice, which is preceded by a severe transient thrombocytopenia thereby limiting its potential therapeutic use. It is demonstrated that INU1-induced CLEC-2 immunodepletion occurs through Src family kinase (SFK)-dependent receptor internalization in vitro and in vivo, presumably followed by intracellular degradation. In mice with spleen tyrosine kinase (Syk) deficiency, INU1-induced CLEC-2 internalization/ degradation was fully preserved, whereas the associated thrombocytopenia was largely prevented. These results show that CLEC-2 can be downregulated from the platelet surface through internalization in vitro and in vivo and that this can be mechanistically uncoupled from the associated antibody-induced thrombocytopenia. Since INU1 IgG induced a pronounced thrombocytopenia, the in vivo effects of monovalent INU1 F(ab) fragments were analyzed. Very unexpectedly, injection of the F(ab) fragments resulted in widespread thrombus formation leading to persistent neurological deficits of the animals. This intravascular thrombus formation is the result of CLEC-2-dependent platelet activation and aggregation. The mechanism underlying the thrombus formation is still unknown and depends potentially on binding of a yet unidentified ligand to F(ab)-opsonized CLEC-2 on platelets. N2 - Die Aggregation von Thrombozyten ist ein essentielle Prozess, um Blutungen nach einer Gefäßverletzung zu stoppen. Sie kann aber auch zu akuten thrombotischen Erkrankungen, wie Herzinfarkt und Schlafanfall, führen. Die Bildung eines stabilen Thrombus ist ein dynamischer Prozess, der ein definiertes Zusammenspiel von thrombozytären Rezeptoren und intrazellulären Signalen benötigt, die zur Adhäsion, Aktivierung und Aggregation der Thrombozyten beitragen. In der hier vorliegenden Dissertation wurde zellulär Regulation von thrombozytären Oberflächenrezeptoren und ihre Beteiligung an der Thromben-Bildung mittels genetisch veränderter Mäuse untersucht. Im ersten Teil der Arbeit wurde die funktionelle Relevanz des immunoreceptor tyrosine-based activation motif (ITAM)-gekoppelten Kollagenrezeptors GPVI und des vor kurzem entdeckten hemITAM-gekoppelten C-type lectin-like receptor 2 (CLEC-2) für die in vivo Thromben-Bildung charakterisiert. Mäuse mit einer Megakaryozyten/ Thrombozyten-spezifischen CLEC-2-Defizienz weisen Defekte in der Entwicklung ihrer lymphatischen Gefäße auf und sind vor arteriellen Gefäßverschlüssen geschützt. Dieser Phänotyp war in Mäusen mit einer Defizient GPVI und CLEC-2 verstärkt. GPVI oder CLEC-2-defiziente Mäuse zeigen eine normale Hämostase, da ihre Schwanzblutungszeiten nur minimal verlängert waren. Die gleichzeitige Defizienz beider Rezeptoren verlängerte die Blutungszeiten der Tiere allerdings erheblich. Das spricht dafür, dass beiden Rezeptoren eine unerwartete redundante Funktion sowohl in der Hämostase als auch während der pathologischen Thromben-Bildung haben. Diese Ergebnisse könnten für die Entwicklung neuer therapeutischen Wirkstoffen, die gegen GPVI und/ oder CLEC-2 gerichtet sind, bedeutsam sein. Im zweiten Teil der Arbeit wurde die zelluläre Regulation von CLEC-2 untersucht. Frühere Studien haben gezeigt, dass die Behandlung von Mäusen mit dem gegen CLEC-2 gerichteten Antikörper INU1 zu einem spezifischen Verlust des Rezeptors in zirkulierenden Thrombozyten führt. Dieser Prozess, der „Immunodepletion“ genannt wird, ist von einer Thrombozytopenie begleitet, die das therapeutische Potential eines solchen Ansatzes reduziert. Im Verlauf der Arbeit konnte gezeigt werden, dass die INU1-abhängige Immunodepletion in vitro und in vivo mittels src family kinase (SFK)-abängiger Internalisierung geschieht. Der Internalisierung ist vermutlich ein intrazellulärer Abbau nachgeschaltet. In Mäusen mit einer spleen tyrosine kinase (Syk) Defizienz war die INU1-abhängige Thrombozytopenie zum größten Teil verhindert, aber die Herabregulation durch Internalisierung von CLEC-2 blieb erhalten. Diese Ergebnisse zeigen, dass CLEC-2 in vitro und in vivo durch Internalisierung von der Thrombozyten-Oberfläche herabreguliert werden kann. Darüber hinaus kann dies von der Antikörper-vermittelten Thrombozytopenie mechanistisch entkoppelt werden. Da die Injektion von INU1 IgG eine starke Thrombozytopenie in der Tieren verursacht, sollen die in vivo Effekte von monovalenten INU1 F(ab) Fragmenten getestet werden. Unerwarteter weise führte die Injektion dieser F(ab) Fragmente zu einer systemischen Thromben-Bildung, die unter anderem neurologische Defizite in den Tieren auslösten. Diese intravaskuläre Thromben-Bildung ist ein Ergebnis von CLEC-2-abhängier Thrombozyten Aktivierung und Aggregation. Der Mechanismus, der dieser Thromben-Bildung zugrunde liegt, ist bisher noch nicht aufgeklärt. Möglicherweise wird er durch die Bindung eines unbekannten Liganden an das F(ab)-gebunde CLEC-2 auf Thrombozyten ausgelöst. KW - Thrombozytenaggregation KW - CLEC-2 Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-116724 ER - TY - THES A1 - Lerch, Maike Franziska T1 - Characterisation of a novel non-coding RNA and its involvement in polysaccharide intercellular adhesin (PIA)-mediated biofilm formation of \(Staphylococcus\) \(epidermidis\) T1 - Charakterisierung einer neuen nicht-kodierenden RNA und deren Beteiligung an der PIA-vermittelten Biofilmbildung von \(Staphylococcus\) \(epidermidis\) N2 - Coagulase-negative staphylococci, particularly Staphylococcus epidermidis, have been recognised as an important cause of health care-associated infections due to catheterisation, and livestock-associated infections. The colonisation of indwelling medical devices is achieved by the formation of biofilms, which are large cell-clusters surrounded by an extracellular matrix. This extracellular matrix consists mainly of PIA (polysaccharide intercellular adhesin), which is encoded by the icaADBC-operon. The importance of icaADBC in clinical strains provoking severe infections initiated numerous investigations of this operon and its regulation within the last two decades. The discovery of a long transcript being located next to icaADBC, downstream of the regulator gene icaR, led to the hypothesis of a possible involvement of this transcript in the regulation of biofilm formation (Eckart, 2006). Goal of this work was to characterise this transcript, named ncRNA IcaZ, in molecular detail and to uncover its functional role in S. epidermidis. The ~400 nt long IcaZ is specific for ica-positive S. epidermidis and is transcribed in early- and mid-exponential growth phase as primary transcript. The promotor sequence and the first nucleotides of icaZ overlap with the 3' UTR of the preceding icaR gene, whereas the terminator sequence is shared by tRNAThr-4, being located convergently to icaZ. Deletion of icaZ resulted in a macroscopic biofilm-negative phenotype with highly diminished PIA-biofilm. Biofilm composition was analysed in vitro by classical crystal violet assays and in vivo by confocal laser scanning microscopy under flow conditions to display biofilm formation in real-time. The mutant showed clear defects in initial adherence and decreased cell-cell adherence, and was therefore not able to form a proper biofilm under flow in contrast to the wildtype. Restoration of PIA upon providing icaZ complementation from plasmids revealed inconsistent results in the various mutant backgrounds. To uncover the functional role of IcaZ, transcriptomic and proteomic analysis was carried out, providing some hints on candidate targets, but the varying biofilm phenotypes of wildtype and icaZ mutants made it difficult to identify direct IcaZ mRNA targets. Pulse expression of icaZ was then used as direct fishing method and computational target predictions were executed with candidate mRNAs from aforesaid approaches. The combined data of these analyses suggested an involvement of icaR in IcaZ-mediated biofilm control. Therefore, RNA binding assays were established for IcaZ and icaR mRNA. A positive gel shift was maintained with icaR 3' UTR and with 5'/3' icaR mRNA fusion product, whereas no gel shift was obtained with icaA mRNA. From these assays, it was assumed that IcaZ regulates icaR mRNA expression in S. epidermidis. S. aureus instead lacks ncRNA IcaZ and its icaR mRNA was shown to undergo autoregulation under so far unknown circumstances by intra- or intermolecular binding of 5' UTR and 3' UTR (Ruiz de los Mozos et al., 2013). Here, the Shine-Dalgarno sequence is blocked through 5'/3' UTR base pairing and RNase III, an endoribonuclease, degrades icaR mRNA, leading to translational blockade. In this work, icaR mRNA autoregulation was therefore analysed experimentally in S. epidermidis and results showed that this specific autoregulation does not take place in this organism. An involvement of RNase III in the degradation process could not be verified here. GFP-reporter plasmids were generated to visualise the interaction, but have to be improved for further investigations. In conclusion, IcaZ was found to interact with icaR mRNA, thereby conceivably interfering with translation initiation of repressor IcaR, and thus to promote PIA synthesis and biofilm formation. In addition, the environmental factor ethanol was found to induce icaZ expression, while only weak or no effects were obtained with NaCl and glucose. Ethanol, actually is an ingredient of disinfectants in hospital settings and known as efficient effector for biofilm induction. As biofilm formation on medical devices is a critical factor hampering treatment of S. epidermidis infections in clinical care, the results of this thesis do not only contribute to better understanding of the complex network of biofilm regulation in staphylococci, but may also have practical relevance in the future. N2 - Koagulase-negative Staphylokokken besiedeln die menschliche und tierische Haut, sowie die Schleimhäute. Durch Läsionen oder das Einbringen von medizinischen Instrumenten wie Kathetern gelangen sie in tiefere Hautschichten oder die Blutbahn und können dort schwerwiegende Infektionen auslösen, vor Allem bei Risikopersonen. Besonders Staphylococcus epidermidis hat sich als Verursacher von nosokomialen Infektionen, aber auch als Pathogen in der Tierhaltung etabliert. Die Bakterien bilden bei der Besiedlung sogenannte Biofilme aus (d.h. eine Akkumulation der Keime, die von einer extrazellulären Matrix umgeben sind). Diese Matrix besteht neben Proteinen und eDNA hauptsächlich aus einem Polysaccharid, dem interzellulären Adhäsin PIA (engl.: polysaccharide intercellular adhesin). Dieses wird durch die Ica-Proteine synthetisiert, die im icaADBC-Operon (engl.: intercellular adhesin operon) kodiert sind. Das Operon hat große Bedeutung in klinischen Stämmen und wurde daher innerhalb der letzten beiden Jahrzehnte eingehend untersucht, auch im Hinblick auf seine Regulation. In der unmittelbaren Umgebung des icaADBC-Operons, stromabwärts des icaR Gens, das für den Repressor des ica-Operons (IcaR) kodiert, wurde ein großes Transkript identifiziert, von dem vermutet wird, dass es möglicherweise an der Regulation der Biofilmbildung beteiligt ist (Eckart, 2006). Ziel dieser Arbeit war es, dieses Transkript zu charakterisieren und seine Funktion in S. epidermidis aufzudecken. Die nicht-kodierende RNA, genannt IcaZ, hat eine Länge von ~400 nt und ist spezifisch für ica-positive S. epidermidis. Sie wird in der frühen bis mittleren exponentiellen Phase temperaturabhängig exprimiert. Stromaufwärts überlappt das icaZ-Gen und dessen Promotor mit der 3' UTR vom icaR-Gen. Stromabwärts wird das icaZ-Gen vom einem Transkriptionsterminator begrenzt, der auch für das tRNAThr-4-Gen benutzt wird, das auf dem gegenüberliegenden Strang in Richtung des icaZ-Gens lokalisiert ist. Die Deletion der RNA führte zu einem makroskopisch sichtbaren Biofilm-negativen Phänotyp mit deutlich verminderter PIA Bildung. Die Biofilmzusammensetzung wurde in vitro mittels eines klassischen Kristallviolett-Assays gemessen und die Biofilmbildung in vivo in Echtzeit mittels konfokaler Mikroskopie (CLSM) betrachtet. Dabei wurde mit einer peristaltischen Pumpe ein Mediumfluss appliziert. Die Mutante zeigte klare Defekte in der initialen Adhärenz und in der Zell-Zell Adhäsion. Sie bildete im Gegensatz zum Wildtyp keinen strukturierten Biofilm aus. Zur Komplementierung des Biofilms wurde die IcaZ von einem Plasmid exprimiert und die Biofilmzusammensetzung nach 18-20 Stunden Wachstum gemessen. Die Ergebnisse dieser Untersuchungen in den verschiedenen Mutanten waren nicht eindeutig. Um die Funktion von IcaZ aufzudecken, wurden Transkriptom- und Proteomvergleiche zwischen Wildtyp und Mutante gemacht. Diese lieferten einige Hinweise, aber da der metabolische Unterschied eines Biofilmbildners zu einem Nicht-Biofilmbildner zu groß war, wurde eine direktere Methode angewandt, die induzierte Expression (Pulsexpression). Zudem wurden potentielle Interaktionspartner der IcaZ mittels computer-basierter Bindungsvorhersagen analysiert. Die icaR mRNA kristallisierte sich dabei als Target heraus und die Interaktion zwischen IcaZ und icaR mRNA wurde mit Gelshift-Assays (EMSA) untersucht. Eine Bandenverschiebung wurde mit icaR 3' UTR und mit dem icaR-5'-3' UTR-Fusionsprodukt detektiert, wohingegen keine Interaktion zwischen IcaZ und icaA mRNA stattfand. Aufgrund dieser Assays wurde vermutet, dass IcaZ die Translation von icaR in S. epidermidis reguliert. In S. aureus fehlt die nicht-kodierende RNA IcaZ und für icaR mRNA wurde eine Autoregulation gezeigt, bei der die icaR 5' UTR mit der icaR 3' UTR intramolekular oder intermolekular durch Basenpaarung interagiert, wodurch die Shine-Dalgarno Sequenz blockiert wird und es aufgrund dessen zu einer Hemmung der Translation kommt. Die Umweltfaktoren, die dazu führen sind bisher unbekannt. Der Komplex wird durch eine Endoribonuklease, RNase III, abgebaut (Ruiz de los Mozos et al., 2013). In S. epidermidis wurde eine solche Interaktion theoretisch ausgeschlossen. Experimentelle Analysen dieser Arbeit haben gezeigt, dass diese Autoregulation in S. epidermidis nicht stattfinden kann und es wird angenommen, dass IcaZ diese Regulation übernimmt. Um die Interaktion zu visualisieren wurden GFP-Reporter Plasmide generiert, die aber für weitere Experimente noch zu verbessern sind. Zusammenfassend lässt sich sagen, dass IcaZ mit der icaR mRNA interagiert, was höchstwahrscheinlich zu einer Hemmung der Translation des Repressors IcaR führt und damit letztlich PIA-Synthese und Biofilmbildung positiv reguliert. Zusätzlich wurde gefunden, dass Ethanol die Expression der IcaZ-RNA induziert, während NaCl nur schwache Effekte zeigte und Glucose keinen Einfluss auf die Expression von icaZ hatte. Ethanol ist ein Bestandteil von Desinfektionsmitteln, die in Krankenhäusern verwendet werden und ist bekannt dafür Biofilmbildung auszulösen. Da die Bildung von Biofilmen auf medizinischen Geräten kritisch ist und diese die Behandlung von S. epidermidis Infektionen erschweren, tragen die Ergebnisse dieser Arbeit nicht nur zu einem besseren Verständnis des komplexen Netzwerks der Biofilmregulation bei, sondern haben möglicherweise auch praktischen Nutzen in der Zukunft. KW - Biofilm KW - Staphylococcus epidermidis KW - Non-coding RNA KW - Hospitalismus KW - icaADBC KW - Nosocomial Infections KW - Polysaccharide intercellular adhesin (PIA) KW - Biofilm formation KW - non-coding RNA KW - ncRNA KW - Nosokomiale Infektionen Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-155777 ER - TY - JOUR T1 - Characterisation of the Hamamatsu photomultipliers for the KM3NeT Neutrino Telescope JF - Journal of Instrumentation N2 - The Hamamatsu R12199-023-inch photomultiplier tube is the photodetector chosen for the first phase of the KM3NeT neutrino telescope. About 7000 photomultipliers have been characterised for dark count rate, timing spread and spurious pulses. The quantum efficiency, the gain and the peak-to-valley ratio have also been measured for a sub-sample in order to determine parameter values needed as input to numerical simulations of the detector. KW - Cherenkov detectors KW - Large detector systems for particle and astroparticle physics KW - Neutrino detectors KW - Photon detectors for UV, visible and IR photons (vacuum) KW - Prototype Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-227744 VL - 13 ER - TY - THES A1 - Bargul, Joel Ltilitan T1 - Characterization of motility and erythrocyte adherence as virulence factors in African trypanosomes T1 - Charakterisierung der Motiliät und Erythrozytenadhärenz als Virulenzfaktoren bei Afrikanischen Trypanosomen N2 - Pathogens causing African animal trypanosomiasis (AAT), the major livestock disease in sub-Saharan Africa, belong to the salivarian group of the African trypanosomes, which are transmitted by the bite of the tsetse fly (Glossina spec.). T. vivax, T. congolense and T. brucei brucei are major pathogens of cattle in particular, causing nagana, with dramatic socio-economic consequences for the affected regions. The parasites additionally have a huge reservoir of other livestock and wild animal hosts. T. brucei, the species which also includes the subspecies pathogenic to humans causing sleeping sickness, has been extensively studied as the cultivatable model trypanosome. But less is known about the other salivarian species, which are not routinely held in culture, if at all possible. A hallmark of trypanosomal lifestyle is the protozoan flagellates incessant motility, which enables them to populate an enormous range of habitats in very diverse hosts. We were now able to characterize, for the first time with high spatiotemporal resolution microscopy, the swimming behaviour and mechanism of the most relevant salivarian species isolated directly from blood. We show the influence of viscosity on the motility of bloodstream form (BSF) cells and simulate their movement between erythrocytes, giving a clear picture of how all analyzed species move under varying environmental conditions. We show that although the basic mechanism of flagellar motility applies to all analyzed species, there are clear morphological differences that produce different reactions to the physical environment. We could define specific conditions for highly increased swimming persistence and speed for compared to the behaviour in standard culture. These results have important implications for the parasites survival strategies in the host, e.g. regarding the capacity for antibody clearance. Although we show all species to effectively remove antibodies from the cell surface, T. congolense differed markedly in its motility behaviour, which gives rise to interesting questions about this species behaviour in the bloodstream. Most of the T. congolense parasites (and to a lesser extent T. vivax) adhere to sheep erythrocytes. Further in vitro studies showed that T. congolense and T. vivax adhered to rabbit, goat, pig and cattle erythrocytes- but binding behaviour was absent in murine blood. Notably, both T. brucei and T. evansi lacked adherence to all studied host erythrocytes. Generally, attachment to blood cells caused reduction of swimming velocities. Judging from its cell architecture, as well as the motility studies in higher media viscosity and in micropillar arrays, T. congolense is not adapted to swim at high speeds in the mammalian bloodstream. Low swimming speeds could allow these purely intravascular parasites to remain bound to the host erythrocytes. N2 - Die wichtigste Viehseuche des subsaharischen Afrika, die afrikanische Trypanosomiasis (AAT), wird durch Pathogene ausgelöst, die zu einer Gruppe der afrikanischen Trypanosomen gehört, die durch den Stich der Tsetsefliege übertragen werden (Salivaria). T. vivax, T. congolense und T. brucei brucei sind die Haupt-Erreger in Rindern, wo sie Nagana verursachen, mit dramatischen sozio-ökonomischen Folgen für die betroffenen Regionen. Die Parasiten haben zusätzlich ein riesiges Reservoir an Zucht- und Wildtieren als Wirte zur Verfügung. T. brucei, die Spezies die auch die humanpathogenen Subspezies umfasst, die Erreger der Schlafkrankheit, ist eingehend als das kultivierbare Trypanosomenmodell untersucht worden, aber es ist weniger über die anderen Salivaria Spezies bekannt, die nicht routinemäßig in Kultur gehalten werden, wenn überhaupt die Möglichkeit besteht. Ein Kennzeichen des trypanosomalen Lebensstils ist die unablässige Motilität der protozooischen Flagellaten, die es ihnen ermöglicht eine riesige Bandbreite an Habitaten in sehr diversen Wirten zu besiedeln. Wir waren in der Lage, zum ersten Mal mit räumlich und zeitlich hochauflösender Mikroskopie, das Schwimmverhalten und den Schwimmmechanismus der wichtigsten Salivaria Spezies zu charakterisieren, die direkt aus dem Blut isoliert wurden. Wir zeigen wie Viskosität die Motilität der Blutstromform (BSF)-Zellen beeinflußt und simulieren deren Bewegung zwischen Erythrozyten. Durch diese Ergebnisse erhalten wir ein klares Bild davon, wie die analysierten Spezies sich unter variierenden experimentellen Bedingungen bewegen. Wir zeigen, dass obwohl der grundlegende Mechanismus der flagellaren Motilität bei allen Spezies gleich ist, es klare morphologische Unterschiede gibt, die verschiedene Reaktionen auf die physikalische Umgebung zur Folge haben. Wir konnten spezifische Konditionen für stark erhöhte Persistenz und Schwimmgeschwindigkeit, im Vergleich zum Verhalten in der Standardkultur, bei T. vivax, T. evansi and T. brucei definieren. Diese Ergebnisse haben wichtige Implikationen für die Überlebensstrategien im Wirt, z.B. bezüglich der Kapazität für die Antikörperentfernung. Obwohl wir zeigen konnten, dass alle Spezies effektiv gebundene Antikörper von ihrer Oberfläche entfernen können, unterscheidet sich T. congolense stark in seinem motilen Verhalten, was interessante Fragen über das Verhalten dieser Spezies im Blutstrom aufwirft. Die meisten T. congolense Parasiten (und in geringerem Ausmaß T. vivax) adhärieren an Erythrozyten des Schafs. Weitere in vitro Versuche zeigten, dass T. congolense und T. vivax auch an Erythrozyten von Kaninchen, Ziege, Schwein und Rind binden, aber nicht im Blut von Mäusen. Interessanterweise adhärierten weder T. brucei noch T. evansi an Erythrozyten irgendeiner Wirts-Spezies. Im Allgemeinen hat die Bindung an Erythrozyten eine Reduktion der Schwimmgeschwindigkeit zur Folge. Nach der Zellarchitektur und dem Verhalten in Medien höherer Viskosität und zwischen Micropillar-Strukturen zu urteilen, ist T. congolense nicht adaptiert, um mit hohen Geschwindigkeiten im Blutstrom von Säugern zu schwimmen. Niedrige Schwimmgeschwindigkeiten könnten diesem rein intravaskulären Parasiten erlauben an den Erythrozyten des Wirts haften zu bleiben. KW - Motiliät KW - African trypanosomes KW - Trypanosomen KW - Erythrozyt KW - motility KW - Antibody clearance KW - erythrocyte adherence KW - Adhäsion KW - Virulenzfaktor KW - Erythrozytenadhärenz Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-115053 ER - TY - THES A1 - Sidiropoulou, Ourania T1 - Characterization of the ATLAS-type Micromegas Detectors T1 - Charakterisierung von Micromegas-Detektoren des ATLAS-Typs N2 - Micromegas are parallel-plate gaseous detectors with micro-pattern readout structures that are able to measure precisely and efficiently at high particle rates. Their difference with respect to other gaseous detectors is that the space in which particles ionise the gas and create electrons is separated from the region in which these electrons are multiplied (or amplified) by a thin metallic mesh. In the ionisation region, typically a few mm thick, a moderate field of a few hundred V/cm is applied. The amplification region with a homogeneous electrical field of 40--50~kV/cm is only 100--150~$\upmu$m thick. The latter guarantees that the positive ions produced in the amplification process are rapidly evacuated and the possibility to build up space charge at high rate is reduced. Critical in micromegas detectors are sparks in the thin amplification region in the presence of the high electrical field. This problem was solved in 2011 by introducing a spark protection scheme. It consists of a layer of resistive strips on top of the readout strips, separated from the latter by a thin insulation layer. Micromegas with the spark protection scheme were selected as instrumentation of the first ATLAS forward muon station (NSW) in the upgrade of the ATLAS detector for the operation of the Large Hadron Collider (LHC) at high luminosity (HL-LHC), expected for 2026. The main subjects of this thesis are: the characterisation of the first micromegas quadruplet prototypes for the NSW detectors; the characterisation of the materials used in the spark-protection system; and the study of the influence of the mesh distance holders (pillars) on the detector performance. The thesis starts with a brief introduction into the LHC and ATLAS projects, followed by a chapter that explains the reason for the upgrade of the ATLAS muon system and shows the layout of the NSW. The first of the three main chapters covers the construction and the characterisation of the first two prototypes for the NSW detectors. These detectors comprise four detection layers and have the same mechanical structure as the NSW detectors. The mechanical precision as well as the homogeneity of the detector response are discussed. The latter has been measured using X-rays and cosmic rays. The spatial resolution that can be achieved with these detectors precision has been measured at the MAMI accelerator at Mainz with low-energy electrons. The chapter is completed by a section that describes the successful integration of a data acquisition system (DAQ) into the official ATLAS DAQ system that was required for an initially planned installation of one of the prototypes on the existing Small Wheel. The next chapter presents a study of the influence of temperature and humidity changes on the resistive strips used in the spark protection system. In addition the long-term stability of the resistive material has been measured accumulating charge equivalent to 100 years of operation in the HL-LHC and exposing the samples to intense gamma irradiation equivalent to 10 years of HL-LHC operation. The third part covers the impact of the mesh distance holders (pillars) on the performance of the detector. This study has been performed with a 10 x 10 cm$^2$ bulk-micromegas with two different pillar shapes. Both 5.9 keV gammas from a $^{55}$Fe and 8 keV X-rays from a Cu target were used. In this context also the electrostatic charge-up of the detector is discussed. In the Appendices one finds a summary of the fundamental physics relevant for gaseous detectors as well as some supporting material for the topics covered in the main part of the thesis. N2 - Micromegas-Detektoren sind Gas-Detektoren aus der Familie der Parallel-Platten-Detektoren mit sehr feinen Auslese-Elementen, die präzise und effizient bei hohen Teilchenraten messen können. Sie unterscheiden sich von anderen Gas-Detektoren dadurch, dass der Bereich, in dem die zu messenden Teilchen das Gas ionisieren und damit Elektronen produzieren, von dem Bereich, in dem diese Elektronen vervielfältigt werden, durch ein feines metallisches Gitter getrennt ist. Im Ionisationsbereich der gewöhnlich mehrere mm dick ist, wird ein moderates elektrisches Feld von einigen hundert Volt angelegt. Der Vervielfachungs- oder Verstärkungsbereich mit einem homogenen elektrischen Feld von $\sim$40--50 kV/cm ist nur 100--150 $\upmu$m dick. Dadurch können die positiven Ionen, die im Vervielfältigungsprozess entstehen, schnell abgeleitet werden und der Aufbau von Raumladung bei hohen Teilchenraten wird begrenzt. Ein kritisches Element der Micromegas Detektoren sind spontane Entladungen in dem starken elektrischen Feld und dem sehr dünnen Verstärkungsbereich. Diese Problem wurde 2011 durch die Einführung einer Schutzschicht gelöst. Diese besteht aus einer dünnen Isolationsschicht über den Auslesestreifen, auf die Widerstandsstreifen aufgebracht werden. Micromegas-Detektoren mit Widerstandsschutz wurden für die Instrumentierung der ersten Station des ATLAS Myon-Systems in Vorwärtsrichtung (NSW) als Mess- und Auslöse-Instrumente für den Betrieb des Large Hadron Colliders (LHC) bei höherer Luminosität (HL-LHC, ab 2020) gewählt. Das Ziel dieser Arbeit ist: 1. die Messung der Eigenschaften der ersten Micromegas NSW Prototypen; 2. die Untersuchung der Eigenschaften des Materials, das für die Widerstandsstreifen benutzt wird; und 3. die Bestimmung des Einflusses der Gitter-Abstandshalter (pillars) auf die Eigenschaften des Detektors. Die Arbeit beginnt mit einer kurzen Einführung, die den LHC und das ATLAS Projekt vorstellt, gefolgt von einem Kapitel, das erklärt, warum die jetzt installierten Myon-Detektoren ersetzt werden müssen, um bei einer konsequenten Erhöhung der LHC-Luminosität nicht an Messgenauigkeit zu verlieren. Es zeigt dann wie die neue Myon Station, das New Small Wheel (NSW), aussehen wird. Im ersten der Hauptkapitel werden der Bau und die Untersuchung der ersten beiden Prototypen für die NSW Detektoren beschrieben. Diese Detektoren (MMSW) bestehen aus vier Messlagen und haben die gleiche mechanische Struktur wie die NSW Detektoren. Sowohl die mechanische Präzision als auch die Homogenität der Signale über den gesamten Detektor und die Teilchen-Nachweiswahrscheinlichkeit werden diskutiert. Letztere wurden mit Röntgenstrahlen und Teilchen aus der kosmischen Strahlung gemessen. Die Ortsauflösung wurde am MAMI Beschleuniger in Mainz mit nieder energetischen Elektronen gemessen. Das Kapitel wird komplettiert durch einen Abschnitt, der die erfolgreiche Integration eines Datenerfassungssystems für die MMSW Detektoren in das offizielle ATLAS Datenerfassungssystem beschreibt. Solch ein System wurde für die ursprünglich geplante Installation eines der MMSW Detektoren in ATLAS gebraucht. Danach wird die Untersuchung der Eigenschaften der Widerstandsstreifen präsentiert, insbesondere deren Abhängigkeit von Temperatur und relativer Luftfeuchtigkeit, sowie ihr Langzeitverhalten. Dafür wurden die Streifen einem Stromfluss ausgesetzt der 100 Jahren Betrieb im LHC entspricht, zum anderen einer Gamma Strahlendosis ausgesetzt, wie sie bei einem 10-jährigen LHC Betrieb erwartet wird. Im dritten Teil folgt eine ausführliche Studie des Einflusses der Gitter-Abstands-halter (pillars) auf die Ortsauflösung und die Nachweiswahrscheinlichkeit. Diese Studie wurde mit einem 10 $\times$ 10 cm$^2$ großen Micromegas Detektor mit zwei verschiedenen Abstandshalterformen sowohl mit 5.9 keV Gamma-Strahlen von einer $^{55}$Fe Quelle, als auch mit 8 keV Photonen aus einer Röntgen-Quelle durchgeführt. In diesem Zusammenhang wird auch die elektrostatische Aufladung des Detektors diskutiert. Im Anhang findet sich eine Zusammenfassung der physikalischen Grundlagen, die für Gasdetektoren relevant sind, sowie zusätzliches Material zu den oben beschriebenen Kapiteln. KW - micromegas detectors KW - ATLAS New Small Wheels (NSW) KW - resistive micromegas KW - micro pattern gaseous detectors KW - muon spectrometer KW - ATLAS KW - Gasionisationsdetektor Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-167323 ER - TY - THES A1 - Heidenreich, Julius Frederik T1 - Characterization of the widely used Rac1-inhibitors NSC23766 and EHT1864 in mouse platelets T1 - Untersuchung der Rac1-Inhibitoren NSC23766 und EHT1864 in murinen Thrombozyten N2 - Platelet activation and aggregation at sites of vascular injury is critical to prevent excessive blood loss, but may also lead to life-threatening ischemic diseases, such as myocardial infarction and stroke. Extracellular agonists induce platelet activation by stimulation of platelet membrane receptors. Signal transduction results in reorganization of the cytoskeleton, shape change, platelet adhesion and aggregation, cumulating in thrombus formation. Several Rho GTPases, including Rac1, Cdc42 and RhoA, are essential mediators of subsequent intracellular transduction of ITAM- and GPCR-signaling. Therefore, inhibition or knockout can result in severely defective platelet signaling. Mice with platelet specific Rac1-deficiency are protected from arterial thrombosis. This benefit highlights further investigation of Rac1-specific functions and its potential as a new pharmacological target for prevention of cardiovascular diseases. Two newly developed synthetic compounds, NSC23766 and EHT1864, were proposed to provide highly specific inhibition of Rac1 activity, but both drugs have never been tested in Rac1-deficient cell systems to rule out potential Rac1-independent effects. This study revealed significant off-target effects of NSC23766 and EHT1864 that occurred in a dose-dependent fashion in both wild-type and Rac1-deficient platelets. Both inhibitors individually affected resting platelets after treatment, either by altering membrane protein expression (NSC23766) or by a marked decrease of platelet viability (EHT1864). Platelet apoptosis could be confirmed by enhanced levels of phosphatidylserine exposure and decreased mitochondrial membrane potential. Phosphorylation studies of the major effector proteins of Rac1 revealed that NSC23766 and EHT1864 abolish PAK1/PAK2 activation independently of Rac1 in wild-type and knockout platelets, which may contribute to the observed off-target effects. Additionally, this study demonstrated the involvement of Rac1 in G protein-coupled receptor-mediated platelet activation and GPIb-induced signaling. Furthermore, the data revealed that Rac1 is dispensable in the process of integrin IIb 3-mediated clot retraction. This study unveiled that new pharmacological approaches in antithrombotic therapy with Rac1 as molecular target have to be designed carefully in order to obtain high specificity and minimize potential off-target effects. N2 - Die Aktivierung und Aggregation von Thrombozyten nach Gefäßverletzungen ist entscheidend um starken Blutverlust zu vermeiden. Allerdings können diese Prozesse auch zu lebensbedrohlichen ischämischen Erkrankungen führen, wie beispielsweise Myokardinfarkt und Schlaganfall. Die Stimulation der Membranrezeptoren durch Triggersubstanzen leitet die Thrombozytenaktivierung und somit die Reorganisation des Zytoskeletts ein. Dies ermöglicht die Adhäsion und Aggregation der Thrombozyten und führt letztendlich zur Thrombusbildung. Die Rho GTPasen Rac1, Cdc42 und RhoA sind als wichtige Mediatoren an der intrazellulären Signaltransduktion beteiligt. Eine medikamentöse Hemmung oder ein genetischer Knockout kann daher die intrazellulären Signalkaskaden so stark beeinträchtigen, dass eine effiziente Aktivierung der Thrombozyten nicht mehr möglich ist. In Mäusen mit thrombozytenspezifischem Knockout von Rac1 wurde festgestellt, dass der Funktionsverlust von Rac1 gleichzeitig auch Schutz vor der Entwicklung von arterieller Thrombose bedeutet. Könnte man sich diese Tatsache pharmakologisch zunutze machen, würde die Hemmung von Rac1 möglicherweise einen neuen, erfolgsversprechenden Ansatz in der Prävention von kardiovaskulären Erkrankungen darstellen. Für den Forschungseinsatz wurden die zwei synthetischen Inhibitoren NSC23766 und EHT1864 entwickelt um Rac1-vermittelte Funktionen zu studieren. Beide Substanzen versprechen eine hochspezifische Hemmung der Rac(1)-Aktivität, wurden bisher jedoch nicht in Zellsystemen mit Rac1-Defizienz verwendet um die Substanzen kritisch auf mögliche, unerwünschte Nebenwirkungen zu untersuchen. In dieser Dissertation wurde gezeigt, dass NSC23766 und EHT1864 zwar effektive Hemmstoffe für Rac1 sind, allerdings genauso Rac1-unabhängige Nebenwirkungen verursachen. Beide Hemmstoffe führten zu Veränderungen der Thrombozyten: Während unter NSC23766 eine verminderte Expression von Membranrezeptoren beobachtet wurde, führte EHT1864 zu einer stark beeinträchtigten Vitalität der Thrombozyten. Anhand von erhöhten Phosphatidylserin-Werten und einer Veränderung des mitochondrialen Membranpotenzials in den behandelten Thrombozyten konnte die EHT1864-vermittelte Apoptose nachgewiesen werden. Letztendlich wurde anhand der verminderten Phosphorylierung von PAK1/PAK2 gezeigt, dass die Aktivierung dieser Rac1-Effektorproteine durch NSC23766 und EHT1864 direkt unterdrückt wird. Zusätzlich zu den Inhibitor-vermittelten Effekten wurde anhand von Rac1-defizienten Thrombozyten nachgewiesen, dass Rac1 auch an GPCR- und GPIb-vermittelten Signalkaskaden beteiligt ist. Außerdem wurde beobachtet, dass Rac1 für die Integrin IIb 3-vermittelte clot retraction entbehrlich ist. Die Ergebnisse dieser Studie legen dar, dass neue pharmakologische Substanzen für die antithrombotische Therapie mit Rac1 als Zielmolekül gründlich erforscht und hinterfragt werden müssen um die Spezifität zu maximieren und vor allem das Nebenwirkungsprofil zu minimieren. KW - Thrombozyt KW - Thrombose KW - Signaltransduktion KW - Enzyminhibitor KW - Rho-Proteine KW - mouse platelets KW - rac1 inhibitors Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-165453 ER - TY - JOUR A1 - Köping, Maria A1 - Shehata-Dieler, Wafaa A1 - Schneider, Dieter A1 - Cebulla, Mario A1 - Oder, Daniel A1 - Müntze, Jonas A1 - Nordbeck, Peter A1 - Wanner, Christoph A1 - Hagen, Rudolf A1 - Schraven, Sebastian P. T1 - Characterization of vertigo and hearing loss in patients with Fabry disease JF - Orphanet Journal of Rare Diseases N2 - Background Fabry Disease (FD) is an X-linked hereditary lysosomal storage disorder which leads to a multisystemic intralysosomal accumulation of globotriaosylceramid (Gb3). Besides prominent renal and cardiac organ involvement, patients commonly complain about vestibulocochlear symptoms like high-frequency hearing loss, tinnitus and vertigo. However, comprehensive data especially on vertigo remain scarce. The aim of this study was to examine the prevalence and characteristics of vertigo and hearing loss in patients with FD, depending on renal and cardiac parameters and get hints about the site and the pattern of the lesions. Methods Single-center study with 57 FD patients. Every patient underwent an oto-rhino-laryngological examination as well as videonystagmography and vestibular evoked myogenic potentials (VEMPs) and audiological measurements using pure tone audiometry and auditory brainstem response audiometry (ABR). Renal function was measured by eGFR, cardiac impairment was graduated by NYHA class. Results More than one out of three patients (35.1%) complained about hearing loss, 54.4% about vertigo and 28.1% about both symptom. In 74% a sensorineural hearing loss of at least 25 dB was found, ABR could exclude any retrocochlear lesion. Caloric testing showed abnormal values in 71.9%, VEMPs were pathological in 68%. A correlation between the side or the shape of hearing loss and pathological vestibular testing could not be revealed. Conclusions Hearing loss and vertigo show a high prevalence in FD. While hearing loss seems due to a cochlear lesion, peripheral vestibular as well as central nervous pathologies cause vertigo. Thus, both the site of lesion and the pathophysiological patterns seem to differ. KW - Fabry disease KW - vertigo KW - VEMP KW - cardiomyopathy KW - chronic kidney disease KW - lysosomal storage disorder Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-222818 VL - 13 ER - TY - INPR A1 - Stennett, Tom A1 - Mattock, James A1 - Pentecost, Leanne A1 - Vargas, Alfredo A1 - Braunschweig, Holger T1 - Chelated Diborenes and their Inverse-Electron-Demand Diels- Alder Reactions with Dienes T2 - Angewandte Chemie, International Edition N2 - A doubly base-stabilized diborane based on a benzylphosphine linker was prepared by a salt elimination reaction between 2-LiC\(_6\)H\(_4\)CH\(_2\)PCy\(_2\).Et\(_2\)O and B\(_2\)Br\(_4\). This compound was reduced with KC8 to its corresponding diborene, with the benzylphosphine forming a five-membered chelate. The diborene reacts with butadiene, 2-trimethylsiloxy-1,3-butadiene and isoprene to form 4,5-diboracyclohexenes, which interconvert between their 1,1- (geminal) and 1,2- (vicinal) chelated isomers. The 1,1-chelated diborene undergoes a halide-catalysed isomerisation into its thermodynamically favoured 1,2-isomer, which undergoes Diels-Alder reactions more slowly than the kinetic product. KW - boron KW - cycloaddition KW - DFT calculations KW - chelates KW - low-valent compounds Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-178268 N1 - This is the pre-peer reviewed version of the following article: T. E. Stennett, J. D. Mattock, L. Pentecost, A. Vargas, H. Braunschweig, Angew. Chem. Int. Ed. 2018, 57, 15276., which has been published in final form at https://doi.org/10.1002/anie.201809217. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions. ER - TY - JOUR A1 - Reiling, Sarah J. A1 - Krohne, Georg A1 - Friedrich, Oliver A1 - Geary, Timothy G. A1 - Rohrbach, Petra T1 - Chloroquine exposure triggers distinct cellular responses in sensitive versus resistant Plasmodium falciparum parasites JF - Scientific Reports N2 - Chloroquine (CQ) treatment failure in Plasmodium falciparum parasites has been documented for decades, but the pharmacological explanation of this phenotype is not fully understood. Current concepts attribute CQ resistance to reduced accumulation of the drug at a given external CQ concentration ([CQ] ex) in resistant compared to sensitive parasites. The implication of this explanation is that the mechanisms of CQ-induced toxicity in resistant and sensitive strains are similar once lethal internal concentrations have been reached. To test this hypothesis, we investigated the mechanism of CQ-induced toxicity in CQ-sensitive (CQS) versus CQ-resistant (CQR) parasites by analyzing the time-course of cellular responses in these strains after exposure to varying [CQ] ex as determined in 72 h toxicity assays. Parasite killing was delayed in CQR parasites for up to 10 h compared to CQS parasites when exposed to equipotent [CQ] ex. In striking contrast, brief exposure (1 h) to lethal [CQ] ex in CQS but not CQR parasites caused the appearance of hitherto undescribed hemozoin (Hz)-containing compartments in the parasite cytosol. Hz-containing compartments were very rarely observed in CQR parasites even after CQ exposures sufficient to cause irreversible cell death. These findings challenge current concepts that CQ killing of malaria parasites is solely concentration-dependent, and instead suggest that CQS and CQR strains fundamentally differ in the consequences of CQ exposure. KW - Cellular imaging KW - Parasite development Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-225123 VL - 8 IS - 11137 ER - TY - JOUR A1 - Rasa, Santa A1 - Nora-Krukle, Zaiga A1 - Henning, Nina A1 - Eliassen, Eva A1 - Shikova, Evelina A1 - Harrer, Thomas A1 - Scheibenbogen, Carmen A1 - Murovska, Modra A1 - Prusty, Bhupesh K. T1 - Chronic viral infections in myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) JF - Journal of Translational Medicine N2 - Background and main text: Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a complex and controversial clinical condition without having established causative factors. Increasing numbers of cases during past decade have created awareness among patients as well as healthcare professionals. Chronic viral infection as a cause of ME/CFS has long been debated. However, lack of large studies involving well-designed patient groups and validated experimental set ups have hindered our knowledge about this disease. Moreover, recent developments regarding molecular mechanism of pathogenesis of various infectious agents cast doubts over validity of several of the past studies. Conclusions: This review aims to compile all the studies done so far to investigate various viral agents that could be associated with ME/CFS. Furthermore, we suggest strategies to better design future studies on the role of viral infections in ME/CFS. KW - ME/CFS KW - Viral infections KW - Biomarkers Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-224960 VL - 16 IS - 268 ER - TY - JOUR A1 - Schulze, Markus A1 - Hutterer, Maria A1 - Sabo, Anja A1 - Hoja, Sabine A1 - Lorenz, Julia A1 - Rothhammer-Hampl, Tanja A1 - Herold-Mende, Christel A1 - Floßbach, Lucia A1 - Monoranu, Camelia A1 - Riemenschneider, Markus J. T1 - Chronophin regulates active vitamin B6 levels and transcriptomic features of glioblastoma cell lines cultured under non-adherent, serum-free conditions JF - BMC Cancer N2 - Background The phosphatase chronophin (CIN/PDXP) has been shown to be an important regulator of glioma cell migration and invasion. It has two known substrates: p-Ser3-cofilin, the phosphorylated form of the actin binding protein cofilin, and pyridoxal 5′-phosphate, the active form of vitamin B6. Phosphoregulation of cofilin, among other functions, plays an important role in cell migration, whereas active vitamin B6 is a cofactor for more than one hundred enzymatic reactions. The role of CIN has yet only been examined in glioblastoma cell line models derived under serum culture conditions. Results We found that CIN is highly expressed in cells cultured under non-adherent, serum-free conditions that are thought to better mimic the in vivo situation. Furthermore, the substrates of CIN, p-Ser3-cofilin and active vitamin B6, were significantly reduced as compared to cell lines cultured in serum-containing medium. To further examine its molecular role we stably knocked down the CIN protein with two different shRNA hairpins in the glioblastoma cell lines NCH421k and NCH644. Both cell lines did not show any significant alterations in proliferation but expression of differentiation markers (such as GFAP or TUBB3) was increased in the knockdown cell lines. In addition, colony formation was significantly impaired in NCH644. Of note, in both cell lines CIN knockdown increased active vitamin B6 levels with vitamin B6 being known to be important for S-adenosylmethionine biosynthesis. Nevertheless, global histone and DNA methylation remained unaltered as was chemoresistance towards temozolomide. To further elucidate the role of phosphocofilin in glioblastoma cells we applied inhibitors for ROCK1/2 and LIMK1/2 to our model. LIMK- and ROCK-inhibitor treatment alone was not toxic for glioblastoma cells. However, it had profound, but antagonistic effects in NCH421k and NCH644 under chemotherapy. Conclusion In non-adherent glioblastoma cell lines cultured in serum-free medium, chronophin knockdown induces phenotypic changes, e.g. in colony formation and transcription, but these are highly dependent on the cellular background. The same is true for phenotypes observed after treatment with inhibitors for kinases regulating cofilin phosphorylation (ROCKs and LIMKs). Targeting the cofilin phosphorylation pathway might therefore not be a straightforward therapeutic option in glioblastoma. KW - chronophin KW - cofilin KW - vitamin metabolism KW - glioma Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-234645 VL - 18 ER - TY - JOUR A1 - Saunders, Rhodri A1 - Davis, Jason A. A1 - Kranke, Peter A1 - Weissbrod, Rachel A1 - Whitaker, David K A1 - Lightdale, Jenifer R T1 - Clinical and economic burden of procedural sedation-related adverse events and their outcomes: analysis from five countries JF - Therapeutics and Clinical Risk Management N2 - Background: Studies have reported on the incidence of sedation-related adverse events (AEs), but little is known about their impact on health care costs and resource use. Methods: Health care providers and payers in five countries were recruited for an online survey by independent administrators to ensure that investigators and respondents were blinded to each other. Surveys were conducted in the local language and began with a "screener" to ensure that respondents had relevant expertise and experience. Responses were analyzed using Excel and R, with the Dixon's Q statistic used to identify and remove outliers. Global and country-specific average treatment patterns were calculated via bootstrapping; costs were mean values. The sum product of costs and intervention probability gave a cost per AE. Results: Responses were received from 101 providers and 26 payers, the majority having. 5 years of experience. At a minimum, the respondents performed a total of 3,430 procedural sedations per month. All AEs detailed occurred in clinical practice in the last year and were reported to cause procedural delays and cancellations in some patients. Standard procedural sedation costs ranged from (sic)74 (Germany) to $2,300 (US). Respondents estimated that AEs would increase costs by between 16% (Italy) and 179% (US). Hypotension was reported as the most commonly observed AE with an associated global mean cost (interquartile range) of $43 ($27-$68). Other frequent AEs, including mild hypotension, bradycardia, tachycardia, mild oxygen desaturation, hypertension, and brief apnea, were estimated to increase health care spending on procedural sedation by $2.2 billion annually in the US. Conclusion: All sedation-related AEs can increase health care costs and result in substantial delays or cancellations of subsequent procedures. The prevention of even minor AEs during procedural sedation may be crucial to ensuring its value as a health care service. KW - costs KW - complications KW - moderate sedation KW - questionnaire KW - survey KW - health care payers Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-227508 VL - 14 ER - TY - JOUR A1 - Gilbert, F. A1 - Schneemann, C. A1 - Scholz, C. J. A1 - Kickuth, R. A1 - Meffert, R. H. A1 - Wildenauer, R. A1 - Lorenz, U. A1 - Kellersmann, R. A1 - Busch, A. T1 - Clinical implications of fracture-associated vascular damage in extremity and pelvic trauma JF - BMC Muscuskeletal Disorders N2 - Background: Vascular damage in polytrauma patients is associated with high mortality and morbidity. Therefore, specific clinical implications of vascular damage with fractures in major trauma patients are reassessed. Methods: This comprehensive nine-year retrospective single center cohort study analyzed demography, laboratory, treatment and outcome data from 3689 patients, 64 patients with fracture-associated vascular injuries were identified and were compared to a control group. Results: Vascular damage occurred in 7% of patients with upper and lower limb and pelvic fractures admitted to the trauma room. Overall survival was 80% in pelvic fracture and 97% in extremity fracture patients and comparable to non-vascular trauma patients. Additional arterial damage required substantial fluid administration and was visible as significantly anemia and disturbed coagulation tests upon admission. Open procedures were done in over 80% of peripheral extremity vascular damage. Endovascular procedures were predominant (87%) in pelvic injury. Conclusion: Vascular damage is associated with high mortality rates especially in combination with pelvic fractures. Initial anemia, disturbed coagulation tests and the need for extensive pre-clinical fluid substitution were observed in the cohort with vascular damage. Therefore, fast diagnosis and early interventional and surgical procedures are necessary to optimize patient-specific outcome. KW - endovascular repair KW - extremity trauma KW - fracture-associated vascular damage KW - level of evidence: IV KW - surgical trauma room KW - pelvic trauma Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-176252 VL - 19 IS - 404 ER - TY - JOUR A1 - Hecht, Markus A1 - Meier, Friedegund A1 - Zimmer, Lisa A1 - Polat, Bülent A1 - Loquai, Carmen A1 - Weishaupt, Carsten A1 - Forschner, Andrea A1 - Gutzmer, Ralf A1 - Utikal, Jochen S. A1 - Goldinger, Simone M. A1 - Geier, Michael A1 - Hassel, Jessica C. A1 - Balermpas, Panagiotis A1 - Kiecker, Felix A1 - Rauschenberg, Ricarda A1 - Dietrich, Ursula A1 - Clemens, Patrick A1 - Berking, Carola A1 - Grabenbauer, Gerhard A1 - Schadendorf, Dirk A1 - Grabbe, Stephan A1 - Schuler, Gerold A1 - Fietkau, Rainer A1 - Distel, Luitpold V. A1 - Heinzerling, Lucie T1 - Clinical outcome of concomitant vs interrupted BRAF inhibitor therapy during radiotherapy in melanoma patients JF - British Journal of Cancer N2 - Background: Concomitant radiation with BRAF inhibitor (BRAFi) therapy may increase radiation-induced side effects but also potentially improve tumour control in melanoma patients. Methods: A total of 155 patients with BRAF-mutated melanoma from 17 European skin cancer centres were retrospectively analysed. Out of these, 87 patients received concomitant radiotherapy and BRAFi (59 vemurafenib, 28 dabrafenib), while in 68 patients BRAFi therapy was interrupted during radiation (51 vemurafenib, 17 dabrafenib). Overall survival was calculated from the first radiation (OSRT) and from start of BRAFi therapy (OSBRAFi). Results: The median duration of BRAFi treatment interruption prior to radiotherapy was 4 days and lasted for 17 days. Median OSRT and OSBRAFi in the entire cohort were 9.8 and 12.6 months in the interrupted group and 7.3 and 11.5 months in the concomitant group (P=0.075/P=0.217), respectively. Interrupted vemurafenib treatment with a median OSRT and OSBRAFi of 10.1 and 13.1 months, respectively, was superior to concomitant vemurafenib treatment with a median OSRT and OSBRAFi of 6.6 and 10.9 months (P=0.004/P=0.067). Interrupted dabrafenib treatment with a median OSRT and OSBRAFi of 7.7 and 9.8 months, respectively, did not differ from concomitant dabrafenib treatment with a median OSRT and OSBRAFi of 9.9 and 11.6 months (P=0.132/P=0.404). Median local control of the irradiated area did not differ in the interrupted and concomitant BRAFi treatment groups (P=0.619). Skin toxicity of grade ≥2 (CTCAE) was significantly increased in patients with concomitant vemurafenib compared to the group with treatment interruption (P=0.002). Conclusions: Interruption of vemurafenib treatment during radiation was associated with better survival and less toxicity compared to concomitant treatment. Due to lower number of patients, the relevance of treatment interruption in dabrafenib treated patients should be further investigated. The results of this analysis indicate that treatment with the BRAFi vemurafenib should be interrupted during radiotherapy. Prospective studies are desperately needed. KW - radiation KW - radiotherapy KW - BRAF KW - vemurafenib KW - dabrafenib Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-227970 VL - 118 ER - TY - JOUR A1 - Hauer, Nadine N. A1 - Popp, Bernt A1 - Schoeller, Eva A1 - Schuhmann, Sarah A1 - Heath, Karen E. A1 - Hisado-Oliva, Alfonso A1 - Klinger, Patricia A1 - Kraus, Cornelia A1 - Trautmann, Udo A1 - Zenker, Martin A1 - Zweier, Christiane A1 - Wiesener, Antje A1 - Jamra, Rami Abou A1 - Kunstmann, Erdmute A1 - Wieczorek, Dagmar A1 - Uebe, Steffen A1 - Ferrazzi, Fulvia A1 - Büttner, Christian A1 - Ekici, Arif B. A1 - Rauch, Anita A1 - Sticht, Heinrich A1 - Dörr, Helmuth-Günther A1 - Reis, André A1 - Thiel, Christian T. T1 - Clinical relevance of systematic phenotyping and exome sequencing in patients with short stature JF - Genetics in Medicine N2 - Purpose Short stature is a common condition of great concern to patients and their families. Mostly genetic in origin, the underlying cause often remains elusive due to clinical and genetic heterogeneity. Methods We systematically phenotyped 565 patients where common nongenetic causes of short stature were excluded, selected 200 representative patients for whole-exome sequencing, and analyzed the identified variants for pathogenicity and the affected genes regarding their functional relevance for growth. Results By standard targeted diagnostic and phenotype assessment, we identified a known disease cause in only 13.6% of the 565 patients. Whole-exome sequencing in 200 patients identified additional mutations in known short-stature genes in 16.5% of these patients who manifested only part of the symptomatology. In 15.5% of the 200 patients our findings were of significant clinical relevance. Heterozygous carriers of recessive skeletal dysplasia alleles represented 3.5% of the cases. Conclusion A combined approach of systematic phenotyping, targeted genetic testing, and whole-exome sequencing allows the identification of the underlying cause of short stature in at least 33% of cases, enabling physicians to improve diagnosis, treatment, and genetic counseling. Exome sequencing significantly increases the diagnostic yield and consequently care in patients with short stature. KW - growth KW - phenotypic spectrum KW - short stature KW - skeletal dysplasia KW - whole-exome sequencing Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-227888 VL - 20 ER - TY - INPR A1 - Stoy, Andreas A1 - Böhnke, Julian A1 - Jiménez-Halla, J. Oscar C. A1 - Dewhurst, Rian D. A1 - Thiess, Torsten A1 - Braunschweig, Holger T1 - CO\(_2\) Binding and Splitting by Boron–Boron Multiple Bonds T2 - Angewandte Chemie, International Edition N2 - CO\(_2\) is found to undergo room-temperature, ambient- pressure reactions with two species containing boron-boron multiple bonds, leading to incorporation of either one or two CO\(_2\) molecules. In one case, a thermally-unstable intermediate was structurally characterized, indicating the operation of an initial 2+2 cycloaddition mechanism in the reaction. KW - carbon dioxide KW - CO2 fixation KW - diborenes KW - diborynes KW - boron Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-164265 N1 - This is the pre-peer reviewed version of the following article: A. Stoy, J. Böhnke, J. O. C. Jiménez‐Halla, R. D. Dewhurst, T. Thiess, H. Braunschweig, Angew. Chem. Int.Ed. 2018, 57,5947 –5951, which has been published in final form at DOI: 10.1002/anie.201802117. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving. ER - TY - GEN A1 - Breitenbach, Tim T1 - Codes of examples for SQH method N2 - Code examples for the paper "On the SQH Scheme to Solve Nonsmooth PDE Optimal Control Problems" by Tim Breitenbach and Alfio Borzì published in the journal "Numerical Functional Analysis and Optimization", in 2019, DOI: 10.1080/01630563.2019.1599911 KW - Code examples KW - SQH method Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-167587 ER - TY - GEN A1 - Breitenbach, Tim T1 - Codes of examples for SQH method N2 - Code examples for the paper "On the SQH Scheme to Solve Nonsmooth PDE Optimal Control Problems" by Tim Breitenbach and Alfio Borzì published in the journal "Numerical Functional Analysis and Optimization", in 2019, DOI: 10.1080/01630563.2019.1599911 KW - Code examples KW - SQH method Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-165669 ER - TY - THES A1 - Wannagat, Wienke Charlotte T1 - Cognitive Processes of Discourse Comprehension in Children and Adults - Comparisons between Written, Auditory, and Audiovisual Modes of Presentation - T1 - Kognitive Prozesse beim Textverstehen bei Kindern und Erwachsenen - Vergleiche zwischen schriftlicher, auditiver und audiovisueller Darbietung - N2 - In drei Studien wurde untersucht, wie sich unterschiedliche Darbietungsformate (schriftlich, auditiv, audiovisuell (auditiv + Bilder) auf das Verständnis semantisch identischer Inhalte auswirken. Dabei interessierte insbesondere der Entwicklungsverlauf von der ersten Klasse bis zum Erwachsenenalter. Dass sich Bilder förderlich auf die Verständnisleistung auswirken können, gilt als gut untersucht (z.B. Carney & Levin, 2002). Anders als viele bisherige Studien erfassen wir Textverstehen mit impliziten Maßen, die differenziertere Rückschlüsse auf die, gängigen Theorien zufolge, zugrundeliegenden Prozesse zulassen: Textverstehen geht mit der Konstruktion von drei Ebenen mentaler Repräsentationen einher (vgl. Kintsch, 1998). Weiterhin bedeutet erfolgreiches Textverstehen, eine auf lokaler und globaler Ebene kohärente mentale Repräsentation zu konstruieren (z.B. Schnotz & Dutke, 2004). Mit einem Satz-Rekognitionstest (vgl. Schmalhofer & Glavanov, 1986) untersuchten wir, ob sich das Gedächtnis für die Textoberfläche, die Textbasis und das Situationsmodell bei 103 8- und 10-Jährigen zwischen schriftlicher, auditiver und audiovisueller (Studie 1) und bei 106 7-, 9- und 11-Jährigen zwischen auditiver und audiovisueller Darbietung narrativer Texte (Studie 2) unterscheidet. Weiterhin (Studie 3) untersuchten wir mit 155 9- und 11-Jährigen, inwieweit sich die Fähigkeit der Inferenzbildung zur Herstellung lokaler und globaler Kohärenz zwischen schriftlicher, auditiver und audiovisueller Darbietung unterscheidet. Als Indikator dienten die Reaktionszeiten auf Wörter, die mit einem über (global)- oder untergeordneten (lokal) Protagonistenziel assoziiert sind. Insgesamt zeigte sich, dass Schüler bis zu einem Alter von 11 Jahren nicht nur die Textoberfläche besser erinnern, sondern auch besser in der Lage sind ein Situationsmodell zu konstruieren, wenn einem Text Bilder beigefügt sind. Dies zeigte sich sowohl im Vergleich mit auditiver als auch mit schriftlicher Darbietung. Bei Erwachsenen zeigte sich kein Effekt der Darbietungsform. Sowohl 9- als auch 11-Jährigen gelingt außerdem die Herstellung globaler Kohärenz bei audiovisueller Darbietung besser als bei auditiver. Die schriftliche Darbietung zeigte sich im Vergleich zur auditiven sowohl im Hinblick auf lokale als auch auf globale Kohärenz überlegen. N2 - In three studies, we investigated, if and how different modes of presentation - written, auditory, audiovisual (auditory combined with pictures) - affect comprehension of semantically identical materials. Children, beginning from the age of 7, and adults were included into the studies. A vast amount of studies have shown that pictures can facilitate text comprehension (e.g. Carney & Levin, 2002). Other than the majority of these previous studies, we assessed text comprehension with methods that we assume to allow more differentiated insights into the cognitive processes that - according to current theories - underlie text comprehension. Text comprehension involves at least three levels of mental representations (see Kintsch, 1998). Moreover, text comprehension means constructing a locally and globally coherent mental representation of the text content. Using a sentence recognition task (see Schmalhofer & Glavanov, 1986), we examined whether the memory of the text surface, the text base, and the situation model differs between written, auditory, and audiovisual text presentation in a sample of 103 8- and 10-year-olds and adults (Study I), and between auditory and audiovisual text presentation in a sample of 106 7-, 9-, and 11-year-olds (Study II). Furthermore, we examined with 155 9- and 11-year-olds, whether the ability to draw inferences to establish local and global coherence differs between written, auditory, and audiovisual text presentation. These inferences were indicated by reaction times to words associated with a protagonist's super- (global) or subordinate (local) goal. Overall, the results of these three studies taken together, indicate that children up to age 11 do not only have better memory of not only the text surface, but also of the situation model when pictures are added to an auditory text. This effect became apparent in comparison with both auditory and written texts. For the adults, in contrast, we did not find an effect of the presentation mode. Furthermore, both 9- and 11-year-olds were better at establishing global coherence at audiovisual compared to auditory text presentation. Written presentation turned out to be superior to auditory presentation in terms of both local and global coherence. KW - Textverstehen KW - text comprehension KW - picture comprehension KW - mental representation KW - coherence KW - children Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-162515 ER - TY - THES A1 - Röding, Sebastian T1 - Coherent Multidimensional Spectroscopy in Molecular Beams and Liquids Using Incoherent Observables T1 - Kohärente Multidimensionale Spektroskopie in Molekularstrahlen und Flüssigkeiten durch inkohärente Observablen N2 - Das Ziel der vorliegenden Arbeit war die Umsetzung einer experimentellen Herangehensweise, welche die kohärente zweidimensionale (2D) Spektroskopie an Proben in unterschiedlichen Aggregatzuständen ermöglicht. Hierzu wurde zunächst ein Aufbau für flüssige Proben realisiert, in welchem die emittierte Fluoreszenz als Messsignal zur Aufnahme der 2D Spektren genutzt wird. Im Gegensatz zu dieser bereits etablierten Methode in der flüssigen Phase stellt die in dieser Arbeit außerdem vorgestellte 2D Spektroskopie an gasförmigen Proben in einem Molekularstrahl einen neuen Ansatz dar. Hierbei werden zum ersten Mal Kationen mittels eines Flugzeitmassenspektrometers als Signal verwendet und somit ionen-spezifische 2D Spektren isolierter Moleküle erhalten. Zusätzlich zu den experimentellen Entwicklungen wurde in dieser Arbeit ein neues Konzept zur Datenerfassung in der 2D Spektroskopie entworfen, welches mit Hilfe einer optimierten Signalabtastung und eines Compressed-Sensing Rekonstruktionsalgorithmus die Aufnahmezeit der Daten deutlich reduziert. Charakteristisch für die in dieser Arbeit eingesetzte Variante der 2D Spektroskopie ist die Verwendung einer phasenkohärenten Sequenz bestehend aus vier Laserimpulsen in einer kollinearen Laserstrahlgeometrie zur Anregung der Probe. Diese Impulssequenz wurde durch einen Laserimpulsformer erzeugt, der durch Änderung der relevanten Laserimpulsparameter mit der Wiederholrate des Lasers eine schnelle Datenerfassung ermöglicht. Die Antwort der Probe auf diese Anregung wurde durch inkohärente Observablen gemessen, welche proportional zur Population des angeregten Zustandes sind, wie zum Beispiel Fluoreszenz oder Ionen. Um aus diesem Signal während der Datenanalyse die gewünschten nichtlinearen Beiträge zu extrahieren, wurde die Messung mit verschiedenen Kombinationen der relativen Phase zwischen den Laserimpulsen wiederholt ("Phase Cycling"). Der Aufbau zur 2D Spektroskopie in flüssiger Phase mit Fluoreszenz-Detektion wurde an Hand von 2D Spektren des Laserfarbstoffes Cresyl Violett charakterisiert. Hierbei wurden Oszillationen in verschiedenen Bereichen des 2D Spektrums beobachtet, welche durch vibronische Kohärenzen hervorgerufen werden und mit früheren Beobachtungen in der Literatur übereinstimmen. Mit dem gleichen Datensatz wurde im nächsten Schritt das neue Konzept zur optimierten Datenerfassung demonstriert. Um ein optimiertes Schema für die Signalabtastung zu finden, wurde ein genetischer Algorithmus implementiert, wobei nur ein Viertel der eigentlichen Datenpunkte zur Messwerterfassung verwendet werden sollte. Dies reduziert die Zeitdauer der Datenerfassung auf ein Viertel der ursprünglichen Messzeit. Die Rekonstruktion des vollständigen Signales erfolgte mit Hilfe einer neuartigen, kompakten Darstellung von 2D Spektren basierend auf der von Neumann Basis. Diese Herangehensweise benötigte im Vergleich zur üblicherweise verwendeten Fourier Basis nur ein Sechstel der Koeffizienten um das Signal vollständig darzustellen und ermöglichte so die erfolgreiche Rekonstruktion der Oszillationen in Cresyl Violett aus einem reduzierten Datensatz. Mit Hilfe der neuartigen kohärenten 2D Spektroskopie an Molekularstrahlen wurden Übergänge von hoch angeregten Rydberg-Zuständen ins ionische Kontinuum in Stickstoffdioxid untersucht. Als dominierender Beitrag stellte sich hierbei der Übergang in auto-ionisierende Zustände heraus. Ein wesentlicher Vorteil der Datenerfassung über ein Flugzeitmassenspektrometer ist die Möglichkeit der gleichzeitigen Aufnahme von 2D Spektren der Edukte und Produkte einer chemischen Reaktion. Dies wurde in Experimenten zur Mehrphotonenionisation gezeigt, in denen deutliche Unterschiede in den 2D Spektren des Stickstoffdioxid-Kations und des Stickstoffmonoxid-Fragmentes sichtbar wurden, welche auf unterschiedliche Antwortfunktionen zurückzuführen sind. Die in dieser Arbeit entwickelten experimentellen Techniken ermöglichen die schnelle Aufnahme von 2D Spektren für Proben in unterschiedlichen Aggregatzuständen und erlauben einen zuverlässigen, direkten Vergleich der Ergebnisse. Sie sind deshalb ein Wegbereiter für zukünftige Untersuchungen der Eigenschaften quantenmechanischer Kohärenzen in photophysikalischen Prozessen oder während photochemischer Reaktionen in unterschiedlichen Aggregatzuständen. N2 - The aim of the present work was to implement an experimental approach that enables coherent two-dimensional (2D) electronic spectroscopy of samples in various states of matter. For samples in the liquid phase, a setup was realized that utilizes the sample fluorescence for the acquisition of 2D spectra. Whereas the liquid-phase approach has been established before, coherent 2D spectroscopy on gaseous samples in a molecular beam as developed in this work is in fact a new method. It employs for the first time cations in a time-of-flight mass spectrometer for signal detection and was used to obtain the first ion-selective 2D spectra of a molecular-beam sample. Additionally, a new acquisition concept was developed in this thesis that significantly decreases measurement times in 2D spectroscopy using optimized sparse sampling and a compressed-sensing reconstruction algorithm. Characteristic for the variant of 2D spectroscopy presented in this work is the usage of a phase-coherent sequence of four laser pulses in a fully collinear geometry for sample excitation. The pulse sequence was generated by a custom-designed pulse shaper that is capable of rapid scanning by changing the pulse parameters such as time delays and phases with the repetition rate of the laser. The sample's response was detected by monitoring incoherent observables that arise from the final-state population, for instance fluorescence or cations. Phase cycling, i.e., signal acquisition with different combinations of the relative phases of the excitation pulses, was applied to extract nonlinear signal contributions from the full signal during data analysis. Liquid-phase 2D fluorescence spectroscopy was established with the laser dye cresyl violet as a sample molecule, confirming coherent oscillations previously observed in literature that are originating from vibronic coherences in specific regions of the 2D spectrum. The data set of this experiment was used subsequently to introduce optimized sparse sampling in 2D spectroscopy. An optimization algorithm was implemented in order to find the best sampling pattern while taking only one quarter of the regular time-domain sampling points, thereby reducing the acquisition time by a factor of four. Signal recovery was based on a new and compact representation of 2D spectra using the von Neumann basis, which required about six times less coefficients than the Fourier basis to retain the relevant information. Successful reconstruction was shown by recovering the coherent oscillations in cresyl violet from a reduced data set. Finally, molecular-beam coherent 2D spectroscopy was introduced with an investigation of ionization pathways in highly-excited nitrogen dioxide, revealing transitions to discrete auto-ionizing states as the dominant contribution to the ion signal. Furthermore, the advantage of the time-of-flight approach to obtain reactant and product 2D spectra simultaneously enabled the observation of distinct differences in the multiphoton-ionization response functions of the nitrogen dioxide cation and the nitrogen oxide ionic fragment. The developed experimental techniques of this work will facilitate fast acquisition of 2D spectra for samples in various states of matter and permit reliable direct comparison of results. Therefore, they pave the way to study the properties of quantum coherences during photophysical processes or photochemical reactions in different environments. KW - Femtosekundenspektroskopie KW - Ultrakurzzeitspektroskopie KW - Pump-Probe Technik KW - Fourier-Spektroskopie KW - Coherent Multidimensional Spectroscopy KW - Time-Resolved Spectroscopy KW - Photochemistry KW - Laser Pulse Shaping KW - Sparse Sampling KW - Kohärente Multidimensionale Spektroskopie KW - Zeitaufgelöste Spektroskopie KW - Photochemie KW - Laserimpulsformung KW - Sparse Sampling Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-156726 ER - TY - JOUR A1 - Roeding, Sebastian A1 - Brixner, Tobias T1 - Coherent two-dimensional electronic mass spectrometry JF - Nature Communications N2 - Coherent two-dimensional (2D) optical spectroscopy has revolutionized our ability to probe many types of couplings and ultrafast dynamics in complex quantum systems. The dynamics and function of any quantum system strongly depend on couplings to the environment. Thus, studying coherent interactions for different environments remains a topic of tremendous interest. Here we introduce coherent 2D electronic mass spectrometry that allows 2D measurements on effusive molecular beams and thus on quantum systems with minimum system-bath interaction and employ this to identify the major ionization pathway of 3d Rydberg states in NO2. Furthermore, we present 2D spectra of multiphoton ionization, disclosing distinct differences in the nonlinear response functions leading to the ionization products. We also realize the equivalent of spectrally resolved transient-absorption measurements without the necessity for acquiring weak absorption changes. Using time-of-flight detection introduces cations as an observable, enabling the 2D spectroscopic study on isolated systems of photophysical and photochemical reactions. KW - Atomic and molecular interactions with photons KW - Excited states KW - Reaction kinetics and dynamics KW - Optical spectroscopy Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-226458 VL - 9 IS - 2519 ER - TY - THES A1 - Lichtenstein, Leonie T1 - Color vision and retinal development of the compound eye in bees T1 - Farbensehen und retinale Entwicklung des Komplexauges bei Bienen N2 - The superfamiliy of bees, Apiformes, comprises more than 20,000 species. Within the group, the eusocial species like honeybees and bumblebees are receiving increased attention due to their outstanding importance for pollination of many crop and wild plants, their exceptional eusocial lifestyle and complex behavioral repertoire, which makes them an interesting invertebrate model to study mechanisms of sensory perception, learning and memory. In bees and most animals, vision is one of the major senses since almost every living organism and many biological processes depend on light energy. Bees show various forms of vision, e.g. color vision, achromatic vision or polarized vision in order to orientate in space, recognize mating partners, detect suitable nest sites and search for rewarding food sources. To catch photons and convert light energy into electric signals, bees possess compound eyes which consists of thousands of single ommatidia comprising a fixed number of photoreceptors; they are characterized by a specific opsin protein with distinct spectral sensitivity. Different visual demands, e.g. the detection of a single virgin queen by a drone, or the identification and discrimination of flowers during foraging bouts by workers, gave rise to the exceptional sex-specific morphology and physiology of male and female compound eyes in honeybees. Since Karl von Frisch first demonstrated color vision in honeybees more than 100 years ago, much effort has been devoted to gain insight into the molecular, morphological and physiological characteristics of (sex-specific) bee compound eyes and the corresponding photoreceptors. However, to date, almost nothing is known about the underlying mechanisms during pupal development which pattern the retina and give rise to the distinct photoreceptor distribution. Hence, in Chapter 2 and 3 I aimed to better understand the retinal development and photoreceptor determination in the honeybee eye. In a first step, the intrinsic temporal expression pattern of opsins within the retina was evaluated by quantifying opsin mRNA expression levels during the pupal phase of honeybee workers and drones. First results revealed that honeybee workers and drones express three different opsin genes, UVop, BLop and Lop1 during pupal development which give rise to an ultraviolet, blue, and green-light sensitive photoreceptor. Moreover, opsin expression patterns differed between both sexes and the onset of a particular opsin occurred at different time points during retinal development. Immunostainings of the developing honeybee retina in Chapter 2 showed that at the beginning of pupation the retina consist only of a thin hypodermis. However, at this stage all retinal structures are already present. From about mid of pupation, opsin expression levels increase and goes hand in hand with the differentiation of the rhabdoms, suggesting a two-step process in photoreceptor development and differentiation in the honeybee compound eye. In a first step the photoreceptor cells meet its fate during late pupation; in a second step, the quantity of opsin expression in each photoreceptor strongly increase up to the 25-fold shortly after eclosion. To date, the underlying mechanisms leading to different photoreceptor types have been intensively studied in the fruit fly, Drosophila melanogaster, and to some extend in butterflies. Interestingly, the molecular mechanisms seemed to be conserved within insects and e.g. the two transcription factors, spalt and spineless, which have been shown to be essential for photoreceptor determination in flies and butterflies, have been also identified in the honeybee. In chapter 3, I investigated the expression patterns of both transcription factors during pupal development of honeybee workers and showed that spalt is mainly expressed during the first few pupal stages which might correlate with the onset of BLop expression. Further, spineless showed a prominent peak at mid of pupation which might initiates the expression of Lop1. However, whether spalt and spineless are also essential for photoreceptor determination in the honeybee has still to be investigated, e.g. by a knockdown/out of the respective transcription factor during retinal development which leads to a spectral phenotype, e.g. a dichromatic eye. Such spectral phenotypes can then be tested in behavioral experiments in order to test the function of specific photoreceptors for color perception and the entrainment of the circadian clock. In order to evaluate the color discrimination capabilities of bees and the quality of color perception, a reliable behavioral experiment under controlled conditions is a prerequisite. Hence, in chapter 4, I aimed to establish the visual PER paradigm as a suitable method for behaviorally testing color vision in bees. Since PER color vision has considered to be difficult in bees and was not successful in Western honeybees without ablating the bee’s antennae or presenting color stimuli in combination with other cues for several decades, the experimental setup was first established in bumblebees which have been shown to be robust and reliable, e.g. during electrophysiological recordings. Workers and drones of the bufftailed bumblebee, Bombus terrestris were able to associate different monochromatic light stimuli with a sugar reward and succeeded in discriminating a rewarded color stimulus from an unrewarded color stimulus. They were also able to retrieve the learned stimulus after two hours, and workers successfully transferred the learned information to a new behavioral context. In the next step, the experimental setup was adapted to honeybees. In chapter 5, I tested the setup in two medium-sized honeybees, the Eastern honeybee, Apis cerana and the Western honeybee, Apis mellifera. Both honeybee species were able to associate and discriminate between two monochromatic light stimuli, blue and green light, with peak sensitivities of 435 nm and 528 nm. Eastern and Western honeybees also successfully retrieve the learned stimulus after two hours, similar to the bumblebees. Visual conditioning setups and training protocols in my study significantly differed from previous studies using PER conditioning. A crucial feature found to be important for a successful visual PER conditioning is the duration of the conditioned stimulus presentation. In chapter 6, I systematically tested different length of stimuli presentations, since visual PER conditioning in earlier studies tended to be only successful when the conditioned stimulus is presented for more than 10 seconds. In this thesis, intact honeybee workers could successfully discriminate two monochromatic lights when the stimulus was presented 10 s before reward was offered, but failed, when the duration of stimulus presentation was shorter than 4 s. In order to allow a more comparable conditioning, I developed a new setup which includes a shutter, driven by a PC based software program. The revised setup allows a more precise and automatized visual PER conditioning, facilitating performance levels comparable to olfactory conditioning and providing now an excellent method to evaluate visual perception and cognition of bees under constant and controlled conditions in future studies. N2 - Die Bienen umfassen weltweit mehr als 20000 Arten, aber besonders eusoziale Honigbienen und Hummeln gewinnen durch ihre essenzielle Rolle bei der Bestäubung vieler Wild- und Kulturpflanzen zunehmend an Bedeutung. Ihr einzigartiger eusozialer Lebensstil, aber auch ihr komplexes Verhaltensrepertoire macht sie zu einem interessanten Insektenmodel, um Mechanismen sensorischer Wahrnehmung, sowie Fähigkeiten des Lernens und Gedächtnisses näher zu untersuchen. Da beinahe jeder lebende Organismus und viele biologische Prozessen durch Sonnenenergie beeinflusst werden, ist die Fähigkeit des Sehens im Tierreich weit verbreitet und zählt auch bei Bienen zu den wichtigsten sensorischen Sinnen. Um geeignete Nistplätze, Futterquellen oder auch Paarungsspartner zu finden, sowie zur Orientierung, nutzen Bienen verschiedenste Formen des Sehens, z. B. Farbensehen, achromatisches Sehen, oder auch das Polarisationssehen. Um Photonen einfangen und diese in ein elektrisches Signal für die weitere Verarbeitung umzuwandeln zu können, besitzen Bienen Komplexaugen, die sich aus mehreren tausend Einzelaugen, den sogeannten Ommatiden zusammensetzen. Jedes Ommatidium enthält eine festgelegte Anzahl an Photorezeptoren, welche durch ein spezifisches Opsin- Protein mit einer bestimmten spektralen Empfindlichkeit charakterisiert sind. Unterschiedliche visuelle Ansprüche wie zum Beispiel die Wahrnehmung einer einzelnen Königin während ihres Paarungsfluges durch einen Drohn oder die Identifizierung und Unterscheidung von Blüten während des Sammelflugs einer Arbeiterin, führten zu einer geschlechtsspezifischen Morphologie und Physiologie männlicher und weiblicher Komplexaugen. Seit Karl von Frisch vor mehr als 100 Jahren zeigen konnte, dass Honigbienen Farben wahrnehmen können, wurden viele Anstrengungen unternommen, ein besseres Verständnis für die molekularen und physiologischen Eigenschaften des (geschlechtsspezifischen) Bienenkomplexauges zu entwickeln. Dennoch ist bis heute wenig über die zugrundeliegenden Mechanismen bekannt, die während der Puppenentwicklung der Biene zur Bildung der Retina und der spezifischen Verteilung der Photorezeptoren innerhalb der Retina führen. Daher wurde in Kapitel 2 dieser Thesis das Ziel verfolgt, die retinale Entwicklung sowie die Determinierung der Photorezeptoren im Honigbienenauge weiter aufzuschlüsseln. In einem ersten Schritt wurde das zeitliche Opsinexpressionsmuster während der Puppenentwicklung von Drohnen und Arbeiterinnen der Honigbiene durch Quantifizierung der Opsin-mRNA Expression, untersucht. Erste Ergebnisse zeigten, dass Drohnen und Arbeiterinnen während ihrer Puppenentwicklung drei verschiedene Opsin-Gene, UVop, BLop und Lop1 exprimieren, welche letztendlich drei verschiedene Photorezeptortypen hervorbringen, einen ultraviolett- , blau- und grün-sensitiven Photorezeptor. Die Opsin-Expressionsmuster unterschieden sich nicht nur zwischen den Geschlechtern, sondern auch im Expressionsbeginn der jeweiligen Opsine während der Retinaentwicklung. Immunfärbungen der sich entwickelnden Retina zeigten außerdem, dass die Retina von Honigbienen zu Beginn ihrer Entwicklung zunächst nur aus einer sehr dünnen Hypodermis besteht, jedoch bereits alle retinale Strukturen enthält. Die Photorezeptordeterminierung bei Honigbienen lässt auf einen zweistufigen Prozess schließen, da ab etwa der Mitte der Verpuppung die Opsinexpression signifikant zunimmt und Hand in Hand mit der Differenzierung der Rhabdome verläuft. Im ersten Schritt, während der späten Puppenphase, erfolgt die Festlegung des Photorezeptortyps in den jeweiligen Photorezeptorzellen. Im zweiten Schritt, kurz nach dem Schlupf der Biene, nimmt dann die Quantität der Opsinexpression stark zu, nämlich bis um das 25-fache. Bisher wurden die zugrundliegenden Mechanismen, die die verschiedenen Photorezeptortypen determinieren, zum Teil in Schmetterlingen, aber besonders intensiv in der Taufliege, Drosophila melanogaster, untersucht. Interessanterweise scheinen die molekularen Mechanismen innerhalb der Insekten konserviert zu sein und beispielsweise die zwei Transkriptionsfaktoren, spalt und spineless, welche während der Photorezeptordeterminierung in Fliegen und Schmetterlingen eine essenzielle Rolle spielen, auch in der Honigbiene identifiziert. In Kapitel 3 habe ich die Expressionsmuster dieser beiden Transkriptionsfaktoren während der Puppenentwicklung von Honigbienenarbeiterinnen untersucht und konnte zeigen, dass spalt hauptsächlich in den ersten Puppenstadien exprimiert wird was vermutlich mit dem Beginn der BLop -Expression korreliert. Spineless zeigte hingegen in der Mitte der Puppenentwicklung einen markantes Maximum in seiner mRNA Expression, was mit der Expression von Lop1 zusammenhängen könnte. Ob spalt und spineless jedoch auch in der Honigbiene eine Rolle in der Photorezeptordeterminierung spielen, bleibt noch zu untersuchen. Zum Beispiel durch einen Knockdown/out des jeweiligen Transkriptionsfaktors während der Retinaentwicklung, der zu einem spektralen Phänotyp, beispielsweise einem dichromatischen Auge, führt. Solche spektralen Phänotypen könnten dann in Verhaltensexperimenten getestet werden, um Aufschluss über die Funktion einzelner Photorezeptoren für das Farbensehen und die Synchronisierung der inneren Uhr gewinnen zu können. Um jedoch die Farbunterscheidungsfähigkeiten von Bienen und die Qualität in der Farbwahrnehmung evaluieren zu können ist ein zuverlässiger Verhaltensversuch vonnöten. Daher war es in Kapitel 4 mein Ziel, das visuelle PER Paradigma als passende Verhaltensmethode für das Testen von Farbensehen in Bienen zu etablieren. Seit mehreren Jahrzehnten gilt die visuelle Konditionierung der PER bei Bienen als schwierig und war bei der europäischen Honigbiene bisher ohne ein Abschneiden der Antennen oder ohne Präsentation weiterer Cues, wie Duft oder Bewegenung, nicht erfolgreich. Daher wurde das experimentelle Setup zunächst bei Hummeln etabliert, welche sich schon in anderen Studien als zuverlässige und robuste Versuchstiere herausgestellt hatten, beispielsweise während elektrophysiologischer Untersuchungen. Arbeiterinnen und Drohnen der schwarzen Erdhummel, Bombus terrestris, waren fähig verschiedene monochromatische Lichtstimuli mit einer Zuckerbelohnung zu assoziieren und schafften es auch, einen unbelohnten von einem belohnten Farbstimulus zu unterscheiden. Auch konnten sie den gelernten Stimulus nach zwei Stunden erneut abrufen und Arbeiterinnen zeigten die Fähigkeit, die gelernte Information erfolgreich in einen neuen Verhaltenskontext zu übertragen. Im nächsten Schritt wurde der Versuchsaufbau für Honigbienen adaptiert, sodass ich diesen in Kapitel 5 bei zwei mittelgroßen Honigbienenarten, der asiatischen Honigbiene, Apis cerana, und in der europäischen Honigbiene, Apis mellifera, verwenden konnte. Beide Honigbienenarten waren fähig, zwei monochromatische Lichtstimuli, Blau und Grün, mit Absorptionsmaxima von 435 nm und 528 nm, mit einer Belohnung zu assoziieren und zwischen beiden Stimuli zu unterscheiden. Ähnlich den Hummeln, konnten auch die asiatischen und europäischen Honigbienen den gelernten Stimulus erfolgreich nach zwei Stunden erneut abrufen. Die visuellen Konditionierungssetups und -Protokolle in meinen Untersuchungen unterschieden sich von denen vorangegangener Studien um einen entscheidenden Faktor, der von besonderer Bedeutung für eine erfolgreiche visuelle Konditionierung der PER von Bienen zu sein scheint, nämlich die Präsentationsdauer des konditionierten Stimulus. Da in vorangegangenen Studien eine visuelle Konditionierung der PER dazu tendierte nur dann erfolgsversprechend zu sein, wenn der konditionierte Stimulus für mehr als 10 s präsentiert wurde, habe ich in Kapitel 6 verschiedene Längen der Stimuluspräsentation systematisch getestet. Unmanipulierte Honigbienenarbeiterinnen konnten erfolgreich zwischen zwei monochromatischen Stimuli unterscheiden, wenn der Stimulus für 10 s präsentiert wurde, aber scheiterten, wenn die Stimuluspräsentation kürzer als 4 s war. Um ein vergleichbareres Konditionieren der Bienen zu ermöglichen, entwickelte ich ein neues Setup, welches einen Shutter beinhaltete, der durch ein PC basiertes Softwareprogramm gesteuert wurde. Das überarbeitete Setup ermöglicht eine präzisiere und automatisierte visuelle PER Konditionierung und bietet nun für zukünftige Studien eine exzellente Methode, visuelle Wahrnehmung und Kognition von Bienen unter konstanten und kontrollierten Bedingungen zu untersuchen. KW - Biene KW - Komplexauge KW - Farbensehen KW - bees KW - compound eyes KW - retinal development KW - color vision KW - Netzhaut KW - Entwicklung Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-150997 ER - TY - JOUR T1 - Combination of inclusive and differential t(t)over-bar charge asymmetry measurements using ATLAS and CMS data at root S=7 and 8 TeV JF - Journal of High Energy Physics N2 - This paper presents combinations of inclusive and differential measurements of the charge asymmetry (A(C)) in top quark pair (t(t)over-bar) events with a lepton+jets signature by the ATLAS and CMS Collaborations, using data from LHC proton-proton collisions at centre-of-mass energies of 7 and 8 TeV. The data correspond to integrated luminosities of about 5 and 20 fb(-1) for each experiment, respectively. The resulting combined LHC measurements of the inclusive charge asymmetry are A(C)(LHC7) = 0.005 +/- 0.007 (stat) +/- 0.006 (syst) at 7 TeV and A(C)(LHC8) = 0.0055 +/- 0.0023 (stat) +/- 0.0025 (syst) at 8 TeV. These values, as well as the combination of A(C) measurements as a function of the invariant mass of the t(t)over-bar system at 8 TeV, are consistent with the respective standard model predictions. KW - Hadron-Hadron scattering (experiments) KW - Patron distributions KW - Top physics KW - PP Collisions Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-312669 VL - 33 IS - 4 ER - TY - THES A1 - Huang, Hua T1 - Comparative investigation of the chemical composition and the water permeability of fruit and leaf cuticles T1 - Vergleichende Untersuchung zur chemischen Zusammensetzung und zur Wasserpermeabilität der Kutikula von Früchten und Blättern N2 - The plant cuticle is a continuous extracellular protective layer covering the outermost surfaces of higher plants that are in contact with the surrounding atmosphere. The primary function of the cuticular lipid membrane, which is mainly composed of biopolymer cutin and cuticular waxes, is to protect the plant organs against uncontrolled water loss. The chemical composition and the biophysical properties of cuticular waxes affect the rate of water diffusion across the cuticle. Fruit transpiration plays an important role in the development and the maintenance of fruit quality. The fruit has been suggested to present better dehydration stress tolerance than the leaf. However, the differences in transpiration and the chemical composition of cuticular waxes between fruit and leaf have yet to be comprehensively investigated. The present study aims to investigate the water permeability and cuticular wax composition of fruit and leaf cuticles of a wide range of plant species and to elucidate the different roles of the cuticular wax components in the transpiration barrier. To address these objectives, fruit and leaf samples from 17 species were investigated. The cuticular transpiration of intact fruits and astomatous adaxial leaf surfaces and the minimum leaf conductance obtained by leaf drying curves for intact leaves were gravimetrically determined for a variety of plant species. The chemical composition of cuticular waxes of fruits and leaves was thoroughly analysed by gas chromatography with flame ionization and mass spectrometry. The water permeability of fruits ranged from 3.7 x 10-5 m s-1 (Prunus domestica subsp. syriaca) to 37.4 x 10-5 m s-1 (Coffea arabica), whereas permeability for leaves varied between 1.6 x 10-5 m s-1 (Cornus officinalis) and 4.5 x 10-5 m s-1 (Prunus domestica subsp. syriaca (L.)). The interspecies range of water permeability of fruits was significantly higher than that of leaves. Chemical analyses of the cuticular waxes demonstrated that fatty acids, primary alcohols, n-alkanes, aldehydes and alkyl esters were the predominant very-long-chain aliphatic compound classes of fruit and leaf surfaces. Sterols, such as β-sitosterol and campesterol, and triterpenoids, such as oleanolic acid, ursolic acid, α-amyrin and ß-amyrin, were the major cyclic compound classes in the cuticular wax membrane. The amount and composition of cuticular waxes of both fruits and leaves varied at an intraspecific level. There were no significant correlations between the total cuticular wax load or the individual cuticular wax composition and the water permeability of fruits or leaves independently or together. After combining the fruit and leaf data set, a significant correlation between the average chain length of very-long-chain aliphatic compounds and permeabilities was detected, i.e. the longer the average chain length, the lower the water permeability. Interestingly, n-Nonacosane (C29) was abundantly detected in fruit waxes of Rosaceae species. These fruits exhibited a relatively low transpiration level, which was very close to their leaf cuticular permeability. The present study suggests that the lower cuticular permeability of leaves, in comparison to that of fruits, may be attributed to the longer average chain length of aliphatic compounds. The accumulation of total wax, triterpenoids and aliphatic compounds may not contribute to the transpiration barrier directly. The present results are highly consistent with the previous model assumptions for the cuticular structure and transport barrier. Furthermore, this comparative study on leaf and fruit cuticles provides further insights linking the cuticular wax chemistry to the physiological properties of the plant cuticle. N2 - Die pflanzliche Kutikula ist eine kontinuierliche extrazelluläre Schutzschicht, welche die oberirdischen primären Abschlussgewebe höherer Pflanzen bedeckt, die in Kontakt mit der umgebenden Atmosphäre stehen. Die primäre Funktion der lipophilen Kutikularmembran, die hauptsächlich aus dem Biopolymer Kutin und kutikulären Wachsen aufgebaut ist, besteht darin, die Pflanzenorgane vor unkontrolliertem Wasserverlust zu schützen. Die chemische Zusammensetzung und die biophysikalischen Eigenschaften von kutikulären Wachsen beeinflussen weitgehend die Geschwindigkeit der Wasserdiffusion über die Kutikula. Die Transpiration von Früchten spielt eine wichtige Rolle in der Ausbildung und Beständigkeit von Fruchtqualitätsmerkmalen. Unterschiede in der Transpiration und der chemischen Zusammensetzung der kutikulären Wachse zwischen Frucht und Blatt sollten untersucht werden. Die vorliegende Studie zielt darauf ab, die Wasserpermeabilität und die kutikuläre Wachszusammensetzung von Früchten und Blättern aus einem breiten Spektrum von Pflanzenarten zu untersuchen und die verschiedenen Rollen der kutikulären Wachskomponenten in den Transpirationsbarriereeigenschaften aufzuklären. Um diesen Zielen näherzukommen, wurden Frucht- und Blattproben von 17 Arten untersucht. Die kutikuläre Transpiration von intakten Früchten und astomatären adaxialen Blattoberflächen ausgewählter Arten sowie der minimale Leitwert von deren Blättern, ermittelt durch Austrocknungskurven mit intakten Blättern, wurden gravimetrisch bestimmt. Die chemische Zusammensetzung der kutikulären Wachse von Früchten und Blättern wurde durch Gaschromatographie mit Flammenionisation und Massenspektrometrie nachgewiesen. Die Wasserdurchlässigkeit von Früchten reichte von 3,7 x 10-5 m s-1 (Prunus domestica subsp. syriaca) bis 37,4 x 10-5 m s-1 (Coffea arabica), während die Werte für Blätter zwischen 1,6 x 10-5 m s-1 (Cornus officinalis) und 4,5 x 10-5 m s-1 variierten (Prunus domestica subsp. syriaca). Der interspezifische Vergleich der Wasserdurchlässigkeit von Früchten war deutlich höher als die der Blätter. Chemische Analysen der kutikulären Wachse zeigten, dass Fettsäuren, primäre Alkohole, n-Alkane, Aldehyde und Alkylester die häufigsten sehr langkettigen aliphatischen Verbindungsklassen für Früchte und Blätter waren. Sterole wie β-Sitosterol und Campesterol und Triterpenoide zum Beispiel Oleanolsäure, Ursolsäure, α-Amyrin und ß-Amyrin, waren die wichtigsten zyklischen Verbindungsklassen in den kutikulären Wachsmischungen. Die Menge und Zusammensetzung der kutikulären Wachse, sowohl von Früchten als auch von Blättern, variierte auf intraspezifischer Ebene. Es waren keine signifikanten Korrelationen zwischen der Menge der kutikulären Wachsablagerung oder der kutikulären Wachszusammensetzung und der Wasserdurchlässigkeit von Frucht- und/oder Blattoberflächen zu erkennen. Wurden die Frucht- und Blattdatensätze zusammen untersucht, so war eine signifikante Korrelation zwischen der durchschnittlichen Kettenlänge von sehr langkettigen aliphatischen Verbindungen und der Permeabilität festzustellen, ging eine längere durchschnittliche Kettenlänge mit geringerer Wasserdurchlässigkeit einher. Interessanterweise wurden große Mengen an n-Nonacosan in Fruchtwachsen der untersuchten Rosaceae-Arten nachgewiesen. Diese Früchte zeigten ein relativ niedriges Transpirationsniveau, das sehr nahe an der Permeabilität ihrer Blattkutikeln lag. Die vorliegende Studie liefert weitere Belege dafür, dass der im Allgemeinen niedrigere minimale Leitwert von Blättern auf die – im Vergleich zur Kutikula von Früchten – längere durchschnittliche Kettenlänge der aliphatischen Verbindungen zurückzuführen ist. Die Anhäufung von Gesamtwachs, Triterpenoiden oder aliphatischen Verbindungen trägt nicht direkt zur Transpirationsbarriere bei. Die vorliegenden Ergebnisse decken sich in hohem Maße mit den bisherigen Modellannahmen zur Struktur der Kutikula und der von ihr vermittelten Funktion als Transpirationsbarriere. Darüber hinaus gibt diese Vergleichsstudie über die Kutikula von Früchten und Blättern zahlreiche Einblicke, die dabei helfen können, die kutikuläre Wachschemie mit den physiologischen Eigenschaften der pflanzlichen Kutikula zu verknüpfen. KW - Cuticle KW - Transpiration barrier KW - Fruit KW - Leaf KW - Permeability KW - ACL KW - Cuticular water permeabilities KW - Cuticular waxes KW - Aliphatics KW - Cyclics KW - Chain-length distribution Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-152948 ER - TY - JOUR A1 - Zoltner, Martin A1 - Krienitz, Nina A1 - Field, Mark C. A1 - Kramer, Susanne T1 - Comparative proteomics of the two T. brucei PABPs suggests that PABP2 controls bulk mRNA JF - PLoS Neglected Tropical Diseases N2 - Poly(A)-binding proteins (PABPs) regulate mRNA fate by controlling stability and translation through interactions with both the poly(A) tail and eIF4F complex. Many organisms have several paralogs of PABPs and eIF4F complex components and it is likely that different eIF4F/PABP complex combinations regulate distinct sets of mRNAs. Trypanosomes have five eIF4G paralogs, six of eIF4E and two PABPs, PABP1 and PABP2. Under starvation, polysomes dissociate and the majority of mRNAs, most translation initiation factors and PABP2 reversibly localise to starvation stress granules. To understand this more broadly we identified a protein interaction cohort for both T. brucei PABPs by cryo-mill/affinity purification-mass spectrometry. PABP1 very specifically interacts with the previously identified interactors eIF4E4 and eIF4G3 and few others. In contrast PABP2 is promiscuous, with a larger set of interactors including most translation initiation factors and most prominently eIF4G1, with its two partners TbG1-IP and TbG1-IP2. Only RBP23 was specific to PABP1, whilst 14 RNA-binding proteins were exclusively immunoprecipitated with PABP2. Significantly, PABP1 and associated proteins are largely excluded from starvation stress granules, but PABP2 and most interactors translocate to granules on starvation. We suggest that PABP1 regulates a small subpopulation of mainly small-sized mRNAs, as it interacts with a small and distinct set of proteins unable to enter the dominant pathway into starvation stress granules and localises preferentially to a subfraction of small polysomes. By contrast PABP2 likely regulates bulk mRNA translation, as it interacts with a wide range of proteins, enters stress granules and distributes over the full range of polysomes. KW - Trypanosoma KW - mRNA KW - T. brucei KW - PABPs Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-177126 VL - 12 IS - 7 ER - TY - JOUR T1 - Comparison between simulated and observed LHC beam backgrounds in the ATLAS experiment at \(E\)\(_{beam}\)=4 TeV JF - Journal of Instrumentation N2 - Results of dedicated Monte Carlo simulations of beam-induced background (BIB) in the ATLAS experiment at the Large Hadron Collider (LHC) are presented and compared with data recorded in 2012. During normal physics operation this background arises mainly from scattering of the 4 TeV protons on residual gas in the beam pipe. Methods of reconstructing the BIB signals in the ATLAS detector, developed and implemented in the simulation chain based on the FLUKA Monte Carlo simulation package, are described. The interaction rates are determined from the residual gas pressure distribution in the LHC ring in order to set an absolute scale on the predicted rates of BIB so that they can be compared quantitatively with data. Through these comparisons the origins of the BIB leading to different observables in the ATLAS detectors are analysed. The level of agreement between simulation results and BIB measurements by ATLAS in 2012 demonstrates that a good understanding of the origin of BIB has been reached. KW - Accelerator modelling and simulations (multi-particle dynamics; single-particle dynamics) KW - Radiation calculations KW - Simulation methods and programs KW - Single-Photon Detectors KW - Search Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-225966 VL - 13 ER - TY - JOUR A1 - Boelch, Sebastian P. A1 - Rueckl, Kilian A1 - Fuchs, Clara A1 - Jordan, Martin A1 - Knauer, Markus A1 - Steinert, Andre A1 - Rudert, Maximilian A1 - Luedemann, Martin T1 - Comparison of elution characteristics and compressive strength of biantibiotic-loaded PMMA bone cement for spacers: Copal\(^®\) spacem with gentamicin and vancomycin versus Palacos\(^®\) R+G with vancomycin JF - BioMed Research International N2 - Purpose. Copal\(^®\) spacem is a new PMMA bone cement for fabricating spacers. This study compares elution of gentamicin, elution of vancomycin, and compressive strength of Copal\(^®\) spacem and of Palacos\(^®\) R+G at different vancomycin loadings in the powder of the cements. We hypothesized that antibiotic elution of Copal\(^®\) spacem is superior at comparable compressive strength. Methods. Compression test specimens were fabricated using Copal\(^®\) spacem manually loaded with 0.5 g gentamicin and additionally 2 g, 4 g, and 6 g of vancomycin per 40 g of cement powder (COP specimens) and using 0.5 g gentamicin premixed Palacos\(^®\) R+G manually loaded with 2 g, 4 g, and 6 g of vancomycin per 40 g of cement powder (PAL specimens). These specimens were used for determination of gentamicin and vancomycin elution (in fetal calf serum, at 22°C) and for determination of compressive strength both prior and following the elution tests. Results. Cumulative gentamicin concentrations (p < 0.005) and gentamicin concentration after 28 days (p ≤ 0.043) were significantly lower for COP specimens compared to PAL specimens. Cumulative vancomycin concentrations were significantly higher (p ≤ 0.043) for COP specimens after the second day. Vancomycin concentrations after 28 days were not significantly higher for the Copal specimens loaded with 2 g and 4 g of vancomycin. Compressive strength was not significantly different between COP specimens and PAL specimens before elution tests. Compressive strength after the elution tests was significantly lower (p = 0.005) for COP specimens loaded with 2 g of vancomycin. Conclusion. We could not demonstrate consistent superior antibiotic elution from Copal\(^®\) spacem compared to Palacos\(^®\) R+G for fabricating gentamicin and vancomycin loaded spacers. The results do not favor Copal\(^®\) spacem over Palacos\(^®\) R+G for the use as a gentamicin and vancomycin biantibiotic-loaded spacer. KW - Copal\(^®\) spacem KW - PMMA bone cement KW - elution KW - compressive strength Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-177435 VL - 2018 IS - 4323518 ER - TY - JOUR A1 - Rosenbaum, David A1 - Blum, Leonore A1 - Schweizer, Paul A1 - Fallgatter, Andreas J. A1 - Herrmann, Martin J. A1 - Ehlis, Ann-Christine A1 - Metzger, Florian G. T1 - Comparison of speed versus complexity effects on the hemodynamic response of the trail making test in block designs JF - Neurophotonics N2 - The use of functional near-infrared spectroscopy (fNIRS) in block designs provides measures of cortical activity in ecologically valid environments. However, in some cases, the use of block designs may be problematic when data are not corrected for performance in a time-restricted block. We sought to investigate the effects of task complexity and processing speed on hemodynamic responses in an fNIRS block design. To differentiate the effects of task complexity and processing speed, 20 subjects completed the trail making test (TMT) in two versions (TMT-A versus TMT-B) and three different speed levels (slow versus moderate versus fast). During TMT-A, subjects are asked to connect encircled numbers in numerically ascending order (1-2-3 ... ). In the more complex TMT-B, subjects are instructed to connect encircled numbers and letters in alternating ascending order (1-A-2-B ... ). To illustrate the obscuring effects of processing speed on task complexity, we perform two different analyses. First, we analyze the classical measures of oxygenated blood, and second, we analyze the measures corrected for the number of processed items. Our results show large effects for processing speed within the bilateral inferior frontal gyrus, left dorsolateral prefrontal cortex, and superior parietal lobule (SPL). The TMT contrast did not show significant effects with classical measures, although trends are observed for higher activation during TMT-B. When corrected for processed items, higher activity for TMT-B in comparison to TMT-A is found within the SPL. The results are discussed in light of recent research designs, and simple to use correction methods are suggested. (c) The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI. KW - functional near-infrared spectroscopy KW - trail making test KW - processing speed KW - task complexity Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-226982 VL - 5 IS - 4 ER - TY - JOUR A1 - Chen, Shasha A1 - Lotz, Christopher A1 - Roewer, Norbert A1 - Broscheit, Jens-Albert T1 - Comparison of volatile anesthetic-induced preconditioning in cardiac and cerebral system: molecular mechanisms and clinical aspects JF - European Journal of Medical Research N2 - Volatile anesthetic-induced preconditioning ( APC) has shown to have cardiac and cerebral protective properties in both pre-clinical models and clinical trials. Interestingly, accumulating evidences demonstrate that, except from some specific characters, the underlying molecular mechanisms of APC-induced protective effects in myocytes and neurons are very similar; they share several major intracellular signaling pathways, including mediating mitochondrial function, release of inflammatory cytokines and cell apoptosis. Among all the experimental results, cortical spreading depolarization is a relative newly discovered cellular mechanism of APC, which, however, just exists in central nervous system. Applying volatile anesthetic preconditioning to clinical practice seems to be a promising cardio- and neuroprotective strategy. In this review, we also summarized and discussed the results of recent clinical research of APC. Despite all the positive experimental evidences, large-scale, long-term, more precisely controlled clinical trials focusing on the perioperative use of volatile anesthetics for organ protection are still needed. KW - APC KW - ischemia-reperfusion injury KW - mitochondria KW - apoptosis Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-175509 VL - 23 IS - 10 ER - TY - JOUR A1 - Herrmann, Johannes A1 - Muenstermann, Marcel A1 - Strobel, Lea A1 - Schubert-Unkmeir, Alexandra A1 - Woodruff, Trent M. A1 - Gray-Owen, Scott D. A1 - Klos, Andreas A1 - Johswich, Kay O. T1 - Complement C5a receptor 1 exacerbates the pathophysiology of N. meningitidis sepsis and is a potential target for disease treatment JF - mBio N2 - Sepsis caused by Neisseria meningitidis (meningococcus) is a rapidly progressing, life-threatening disease. Because its initial symptoms are rather unspecific, medical attention is often sought too late, i.e., when the systemic inflammatory response is already unleashed. This in turn limits the success of antibiotic treatment. The complement system is generally accepted as the most important innate immune determinant against invasive meningococcal disease since it protects the host through the bactericidal membrane attack complex. However, complement activation concomitantly liberates the C5a peptide, and it remains unclear whether this potent anaphylatoxin contributes to protection and/or drives the rapidly progressing immunopathogenesis associated with meningococcal disease. Here, we dissected the specific contribution of C5a receptor 1 (C5aR1), the canonical receptor for C5a, using a mouse model of meningococcal sepsis. Mice lacking C3 or C5 displayed susceptibility that was enhanced by >1,000-fold or 100-fold, respectively, consistent with the contribution of these components to protection. In clear contrast, C5ar1\(^{-/-}\) mice resisted invasive meningococcal infection and cleared N. meningitidis more rapidly than wild-type (WT) animals. This favorable outcome stemmed from an ameliorated inflammatory cytokine response to N. meningitidis in C5ar1\(^{-/-}\) mice in both in vivo and ex vivo whole-blood infections. In addition, inhibition of C5aR1 signaling without interference with the complement bactericidal activity reduced the inflammatory response also in human whole blood. Enticingly, pharmacologic C5aR1 blockade enhanced mouse survival and lowered meningococcal burden even when the treatment was administered after sepsis induction. Together, our findings demonstrate that C5aR1 drives the pathophysiology associated with meningococcal sepsis and provides a promising target for adjunctive therapy. Importance: The devastating consequences of N. meningitidis sepsis arise due to the rapidly arising and self-propagating inflammatory response that mobilizes antibacterial defenses but also drives the immunopathology associated with meningococcemia. The complement cascade provides innate broad-spectrum protection against infection by directly damaging the envelope of pathogenic microbes through the membrane attack complex and triggers an inflammatory response via the C5a peptide and its receptor C5aR1 aimed at mobilizing cellular effectors of immunity. Here, we consider the potential of separating the bactericidal activities of the complement cascade from its immune activating function to improve outcome of N. meningitidis sepsis. Our findings demonstrate that the specific genetic or pharmacological disruption of C5aR1 rapidly ameliorates disease by suppressing the pathogenic inflammatory response and, surprisingly, allows faster clearance of the bacterial infection. This outcome provides a clear demonstration of the therapeutic benefit of the use of C5aR1-specific inhibitors to improve the outcome of invasive meningococcal disease. KW - C5aR1 KW - whole-blood model KW - Neisseria meningitidis KW - anaphylatoxins KW - complement system KW - inflammation KW - invasive disease KW - mouse model KW - neutrophils KW - sepsis Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-175792 VL - 9 IS - 1 ER - TY - THES A1 - Toepfer, Franziska Helene T1 - Component selectivity and multistability in a \(Drosophila\) orientation paradigm using incoherent motion stimuli T1 - Komponenten-Selektivität und Multistabilität in einem Orientierungsparadigma für \(Drosophila\) unter Verwendung inkohärenter Bewegungsreize N2 - Visual information is essential for Drosophila to navigate its environment. The visual system of the fly has been studied for many decades and has yielded many insights about vision in general. However, visual information can be ambiguous and the system processing it needs to be able to cope with that. In this study, the visual orientation behavior of Drosophila is challenged by panoramic incoherent motion stimuli to which the fly can respond in three different, equally adaptive ways. The study is conducted in a well-established setup, the so-called flight simulator (Heisenberg and Wolf, 1993), where the fly can control its visual surroundings in stationary flight with its yaw torque, which is simultaneously recorded. The fly can either use one of two incoherently moving panorama patterns or the integrated motion of both as its reference for straight flight. It is observed that flies use all three of these behavioral alternatives for orientation. Previous models of fly motion vision do not predict a bimodal tuning to incoherent wide-field motion stimuli (Joesch et al., 2008, Borst et al., 1995), however, a recent study on blowflies could suggests that they show component selectivity to the individual moving gratings in a compound plaid stimulus (Saleem et al., 2012). Here, it can be shown that the same bimodal tuning manifests in Drosophila, although the stimuli used are different and most of the experiments are conducted in closed loop. It is found that the extent to which the Drosophila expresses this component selectivity in its orientation behavior, i.e. how often it stabilizes a single panorama pattern instead of the integrated motion of both, depends on two properties of the panorama stimuli, pattern contrast and horizontal pattern element distance. Single pattern stabilization decreases with increasing contrast and increasing pattern element distance. In the latter case, it increases again when there are very few horizontal pattern elements, although that appears to be the result of a lack of rivalry between the patterns due to the low number of pattern elements. Both increased pattern contrast and pattern element distance increase the salience of the single pattern elements. A single element in a compound visual stimulus, like a dot within a dot pattern, can be interpreted as a standalone figure or a part of a bigger unit. Previous studies on Drosophila vision have concentrated on how the fly discriminates a figure from the background (Heisenberg and Wolf, 1984, Bahl et al., 2013, Aptekar et al., 2012), but have hardly touched the question of what qualifies a figure or a background (i.e. a panorama) stimulus as such. In the present study, it is observed that, when exposed to incoherent panoramic motion stimuli, the flies prefer to orient themselves towards the average of the two motions when the panorama stimuli possess strong figure features and towards the single patterns when they do not and single pattern elements are therefore less salient. The above-mentioned plaid stimuli are a well-known multistable percept in human psychophysics. Multistability is a property of higher visual systems and considered an indicator of endogenous activity in vision. As Drosophila expresses behavioral multistability in the IPMP, it is evaluated in this respect. The results show several parallels to human multistable perception. For one, the frequency and duration with which a behavior occurs, can be influenced, but the occurrence of the behaviors is non-deterministic and not coupled to the stimulus. It can also be shown that the switches between behaviors do not stem from a rivalry of the two visual hemispheres of the fly, although monocularity does also influence the likelihood with which the behaviors occur. Secondly, like in human perceptual rivalry, individual flies exhibit strong idiosyncrasies regarding the overall durations they spend with the different behaviors and the frequencies with which they switch between them. Finally, the distribution of the durations between the behavioral switches can be fit to the same function as the distribution of percept durations in human multistable perception, the gamma function, although it has a different shape and therefore also differing parameters. The Drosophila mutant radish, which has been shown to have attention-like deficits (van Swinderen and Brembs, 2010, Koenig et al., 2016a), does also express an altered behavior in the IPMP compared to wildtype flies. As these behavioral alterations resemble effects on multistable perception found in humans suffering from ADHD (Amador-Campos et al., 2015) and perceptual multistability is generally considered to be closely related to attention (Leopold and Logothetis, 1999), attentional processes are also very likely to play a role in the flies’ behavior in the IPMP. In conclusion, the visual system of Drosophila is capable disentangle incoherent motion stimuli even if they overlap and cover the entire visual field, i.e. it shows component selectivity of wide-field motion. Whether it uses a single wide-field motion component or the average of two as its reference for straight flight depends on pattern contrast and horizontal pattern element density, which indicates an involvement of a figure-background rivalry. This rivalry and the one between the two wide-field motion components elicit a multistability in the orientation behavior of the fly the temporal dynamics of which partially resemble the temporal dynamics of human multistable perception and which also suggests the involvement of attentional processes. N2 - Visuelle Information ist von wesentlicher Bedeutung für Drosophila um sich in ihrer Umgebung zurecht zu finden. Das visuelle System der Fliege wird seit vielen Jahrzehnten untersucht und hat wichtige Erkenntnisse über Sehen im Allgemeinen hervorgebracht. Visuelle Information kann mehrdeutig sein und das System, das sie verarbeitet muss in der Lage sein damit umzugehen. In dieser Arbeit wird das visuelle Orientierungsverhalten von Drosophila durch inkohärente Großfeldbewegungen herausgefordert, auf die die Fliege auf drei verschiedene, gleich plausible Weisen reagieren kann. Die Studie wird in einem etablierten Versuchsaufbau durchgeführt, dem sogenannten Flugsimulator (Heisenberg and Wolf, 1993), in dem die Fliege im stationären Flug ihren visuellen Input mit ihrem Drehmoment kontrollieren kann. Die Fliege kann entweder eines von zwei sich inkohärent bewegenden Panoramamustern oder deren integrierte Gesamtbewegung als Referenz für ihren Geradeausflug nutzen. Es wird beobachtet, dass die Fliegen alle drei dieser Verhaltens-Alternativen zur Orientierung benutzen. Bisherige Modelle des Bewegungssehens der Fliege sagen keine bimodale Reaktion auf inkohärente Bewegungsreize vorher (Borst et al., 1995, Joesch et al., 2008), allerdings konnte kürzlich eine Studie an Calliphora zeigen, dass diese Komponenten-Selektivität bezüglich der einzelnen Bewegungen der Streifenmuster eines daraus zusammengesetzten Karomusters zeigen (Saleem et al., 2012). Hier kann gezeigt werden, dass diese bimodale Reaktion auch in Drosophila der Fall ist, obwohl die visuellen Stimuli unterschiedlich sind und die meisten Experimente im geschlossenen Regelkreis durchgeführt werden. Des weiteren zeigt sich, dass der Umfang in dem Drosophila diese Komponentenselektivität in ihrem Orientierungsverhalten zeigt, d.h. wie häufig sie ein einzelnes Panoramamuster statt der integrierten Bewegung von beiden stabilisiert, von zwei Eigenschaften des Musters, dem Musterkontrast und dem horizontalen Abstand der einzelnen Musterelemente, abhängt. Die Einzelmusterstabilisierung nimmt mit steigendem Kontrast und steigendem Musterelementabstand ab. Bei letzterem steigt sie wieder, wenn die Anzahl der horizontalen Musterelemente sehr gering ist, allerdings scheint dies das Ergebnis von fehlender Konkurrenz zwischen den Mustern aufgrund der niedrigen Anzahl der Musterelemente zu sein. Sowohl gesteigerter Kontrast und Musterelementabstand steigern das Hervorstechen der einzelnen Musterelemente. Ein einzelnes Element in einem zusammengesetzen visuellen Stimulus, wie ein Punkt in einem Punktemuster, kann sowohl als alleinstehendes Objekt als auch als Teil einer größeren Einheit interpretiert werden. Bisherige Studien am visuellen System von Drosophila haben sich darauf konzentriert, wie die Fliege ein Objekt vom Hintergrund unterscheidet (Aptekar et al., 2012, Bahl et al., 2013, Heisenberg and Wolf, 1984), aber kaum behandelt, was ein Objekt oder einen Hintergrund als solchen definiert. In dieser Studie wird beobachtet, dass die Fliege, wenn sie mit zwei sich inkohärent bewegenden Panoramastimuli konfrontiert wird, es bevorzugt sich am Mittelwert der beiden Bewegungen zu orientieren, wenn diese starke Objekteigenschaften aufweisen und an den Einzelmustern, wenn sie dies nicht der Fall ist und die einzelnen Musterelement daher weniger stark hervorstehen. Die erwähnten Karomusterreize sind ein bekanntes Beispiel multistabiler Wahrnehmung der Humanpsychophysik. Multistabilität ist eine Eigenschaft höherer visueller Systeme und ein Indikator von endogener Aktivität. Da Drosophila Multistabilität in ihrem Verhalten im IPMP aufweist, wird es diesbezüglich ausgewertet. Die Ergebnisse zeigen mehrere Parallelen zur menschlichen multistabilen Wahrnehmung. Zum einen kann die Häufigkeit und die Dauer mit der ein Verhalten auftritt, beeinflusst werden, aber das Auftreten der Verhaltensweisen ist nicht deterministisch und nicht an den Stimulus gekoppelt. Es kann auch gezeigt werden, dass die Wechsel zwischen den Verhaltensweisen nicht von einer Rivalität zwischen den beiden visuellen Hemisphären der Fliege herrühren, obwohl Monokularität die Wahrscheinlichkeit mit der die Verhaltensweisen auftreten, beeinflusst. Zweitens weisen die einzelnen Fliegen, wie auch Menschen in multistabilen Wahrnehmungsparadigmen, starke Idiosynkrasien bezüglich der Gesamtdauer, die sie mit einem Verhalten verbringen und der Häufigkeit mit der sie zwischen diesen hin und her wechseln, auf. Schließlich folgt die Verteilung der Zeitspannen zwischen den Wechseln zwischen den Verhaltensweisen der gleichen Funktion wie die Verteilung der Wahrnehmungsdauern in der menschlichen multistabilen Wahrnehmung, der Gamma-Funktion, obwohl sie eine unterschiedliche Form hat und daher auch andere Parameter. Die Drosophila-Mutante radish, von der gezeigt werden konnte, dass sie aufmerksamkeits-ähnliche Defizite hat (van Swinderen and Brembs, 2010, Koenig et al., 2016a), zeigt im Vergleich mit wildtypischen Fliegen auch im IPMP ein verändertes Verhalten. Da diese Veränderungen Effekten auf multistabile Wahrnehmung ähneln, die bei ADHS-Patienten gefunden wurden (Amador-Campos et al., 2015) und multistabile Wahrnehmung im Allgemeinen als nahe verwandt mit Aufmerksamkeit angesehen wird (Leopold and Logothetis, 1999), spielen Aufmerksamkeitsprozesse sehr wahrscheinlich auch eine Rolle im Verhalten der Fliege im IPMP. Zusammenfassend kann gesagt werden, dass das visuelle System von Drosophila in der Lage ist inkohärente Bewegungsreize sogar dann zu trennen wenn diese vollständig überlappen und das gesamte Sehfeld umfassen, d.h. es weist Komponentenselektivität von Großfeldbewegungen auf. Ob sie eine einzele Großfeldbewegungskomponente oder den Mittelwert von Zweien als Referenz für Geradeausflug nutzt, hängt von Kontrast und Dichte der horizontalen Musterelemente ab, was eine Beteiligung einer Objekt-Hintergrund-Rivalität impliziert. Diese Rivalität und diejenige zwischen den beiden Großfeldbewegungskomponenten lösen eine Multistabilität im Orientierungsverhalten der Fliege aus, deren zeitliche Dynamik teilweise der der menschlichen multistabilen Wahrnehmung entspricht und die die Beteiligung von Aufmerksamkeitsprozessen wahrscheinlich macht. KW - Drosophila KW - Invertebrate vision KW - Transparent motion KW - Component selectivity Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-153346 ER -