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Sonstige beteiligte Institutionen
- DFG Forschungsgruppe 2757 / Lokale Selbstregelungen im Kontext schwacher Staatlichkeit in Antike und Moderne (LoSAM) (2)
- Klinikum Fulda (2)
- Ökologische Station Fabrikschleichach (2)
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- Akademie der Wissenschaften und der Literatur, Mainz (1)
- Apotheke, Universitätsklinikum Würzburg (1)
- Biomedical Center Munich, Department of Physiological Chemistry, Ludwig-Maximilians-Universität München (1)
- Bundeswehr Institute of Radiobiology affiliated to the University of Ulm, Munich, Germany (1)
- Clinical Trial Center (CTC) / Zentrale für Klinische Studien Würzburg (ZKSW) (1)
- Cologne Game Lab (1)
(1) Background: about 10% of Wilms Tumor (WT) patients have a malformation or cancer predisposition syndrome (CPS) with causative germline genetic or epigenetic variants. Knowledge on CPS is essential for genetic counselling. (2) Methods: this retrospective analysis focused on 2927 consecutive patients with WTs registered between 1989 and 2017 in the SIOP/GPOH studies. (3) Results: Genitourinary malformations (GU, N = 66, 2.3%), Beckwith-Wiedemann spectrum (BWS, N = 32, 1.1%), isolated hemihypertrophy (IHH, N = 29, 1.0%), Denys-Drash syndrome (DDS, N = 24, 0.8%) and WAGR syndrome (N = 20, 0.7%) were reported most frequently. Compared to others, these patients were younger at WT diagnosis (median age 24.5 months vs. 39.0 months), had smaller tumors (349.4 mL vs. 487.5 mL), less often metastasis (8.2% vs. 18%), but more often nephroblastomatosis (12.9% vs. 1.9%). WT with IHH was associated with blastemal WT and DDS with stromal subtype. Bilateral WTs were common in WAGR (30%), DDS (29%) and BWS (31%). Chemotherapy induced reduction in tumor volume was poor in DDS (0.4% increase) and favorable in BWS (86.9% reduction). The event-free survival (EFS) of patients with BWS was significantly (p = 0.002) worse than in others. (4) Conclusions: CPS should be considered in WTs with specific clinical features resulting in referral to a geneticist. Their outcome was not always favorable.
Cyclic adenosine monophosphate (cAMP), the ubiquitous second messenger produced upon stimulation of GPCRs which couple to the stimulatory GS protein, orchestrates an array of physiological processes including cardiac function, neuronal plasticity, immune responses, cellular proliferation and apoptosis. By interacting with various effector proteins, among others protein kinase A (PKA) and exchange proteins directly activated by cAMP (Epac), it triggers signaling cascades for the cellular response. Although the functional outcomes of GSPCR-activation are very diverse depending on the extracellular stimulus, they are all mediated exclusively by this single second messenger. Thus, the question arises how specificity in such responses may be attained. A hypothesis to explain signaling specificity is that cellular signaling architecture, and thus precise operation of cAMP in space and time would appear to be essential to achieve signaling specificity. Compartments with elevated cAMP levels would allow specific signal relay from receptors to effectors within a micro- or nanometer range, setting the molecular basis for signaling specificity. Although the paradigm of signaling compartmentation gains continuous recognition and is thoroughly being investigated, the molecular composition of such compartments and how they are maintained remains to be elucidated. In addition, such compartments would require very restricted diffusion of cAMP, but all direct measurements have indicated that it can diffuse in cells almost freely.
In this work, we present the identification and characterize of a cAMP signaling compartment at a GSPCR. We created a Förster resonance energy transfer (FRET)-based receptor-sensor conjugate, allowing us to study cAMP dynamics in direct vicinity of the human glucagone-like peptide 1 receptor (hGLP1R). Additional targeting of analogous sensors to the plasma membrane and the cytosol enables assessment of cAMP dynamics in different subcellular regions. We compare both basal and stimulated cAMP levels and study cAMP crosstalk of different receptors. With the design of novel receptor nanorulers up to 60nm in length, which allow mapping cAMP levels in nanometer distance from the hGLP1R, we identify a cAMP nanodomain surrounding it. Further, we show that phosphodiesterases (PDEs), the only enzymes known to degrade cAMP, are decisive in constraining cAMP diffusion into the cytosol thereby maintaining a cAMP gradient. Following the discovery of this nanodomain, we sought to investigate whether downstream effectors such as PKA are present and active within the domain, additionally studying the role of A-kinase anchoring proteins (AKAPs) in targeting PKA to the receptor compartment. We demonstrate that GLP1-produced cAMP signals translate into local nanodomain-restricted PKA phosphorylation and determine that AKAP-tethering is essential for nanodomain PKA.
Taken together, our results provide evidence for the existence of a dynamic, receptor associated cAMP nanodomain and give prospect for which key proteins are likely to be involved in its formation. These conditions would allow cAMP to exert its function in a spatially and temporally restricted manner, setting the basis for a cell to achieve signaling specificity. Understanding the molecular mechanism of cAMP signaling would allow modulation and thus regulation of GPCR signaling, taking advantage of it for pharmacological treatment.
Synthetische anorganische Knochenersatzmaterialien auf Calcium-Phosphat- und Magnesium-Phosphat-Basis wurden in der hier vorliegenden Dissertation mit verschiedenen handelsüblichen Antibiotika versetzt und deren Freisetzungsverhalten charakterisiert. Zudem wurde der Einfluss des Antibiotikazusatzes auf bestimmte materialcharakteristische Eigenschaften untersucht, hierbei fanden die Quecksilberporosimetrie, die Röntgendiffraktometrie und die Rasterelektronenmikroskopie ihre Anwendung. Insbesondere für die Knochenersatzmaterialien auf Calcium-Phosphat-Basis sollte eine klinisch praktikable und demnach möglichst einfache Methode etabliert werden, um die Kombination mit einem Antibiotikum durchzuführen. Die Detektion der Antibiotika erfolgte mit Hilfe eines UV/VIS-Spektrophotometers. Zudem wurde für einige ausgewählte Kombinationen aus Antibiotikum und Knochenersatzmaterial durch einen Agardiffusionstest die antibakterielle Wirkung nach der Freisetzung aus dem jeweiligen Trägermaterial bestätigt.
Während der letzten Jahrzehnte ist eine steigende Inzidenz von Infektionen durch Pilze der Ordnung Mucorales zu beobachten. Rhizopus arrhizus ist der häufigste Erreger dieser lebensbedrohlichen Infektionen, die vor allem immunsupprimierte Patienten betreffen. Aufgrund der oft schwierigen Diagnosestellung und limitierter therapeutischer Optionen liegt derzeit die Letalität von Mucormykosen zwischen 50 bis 100 %. Eine Voraussetzung für die Etablierung neuer Biomarker oder immuntherapeutischer Strategien ist ein verbessertes Verständnis der immunpathologischen Prozesse bei der Abwehr von Mucorales.
In dieser Arbeit wurden daher verschiedene Immunzellpopulationen durch ruhende und ausgekeimte Stadien von R. arrhizus stimuliert und anschließend deren proinflammatorische Immunantwort gemessen. Als Vergleich diente die proinflammatorische Immunantwort der untersuchten Immunzellen nach Stimulation mit Aspergillus fumigatus. Darüber hinaus war es Gegenstand dieser Arbeit, zu charakterisieren welche Pattern Recognition Receptors (PRRs) an der Erkennung von Mucorales durch verschiedene innate Immunzellen beteiligt sind. Zugleich wurde untersucht, ob unterschiedliche Morphotypen der Pilzspezies Auswirkungen auf die Stimulation der jeweiligen PRRs haben. Hierfür wurden Koinkubations-Experimente mit neutrophilen Granulozyten sowie Peripheral Blood Mononuclear Cells (PBMCs), Monozyten und monocyte derived dendritic cells (moDCs) mit verschiedenen Morphotypen von R. arrhizus durchgeführt. Die Rezeptoren TLR2, TLR4 und/oder Dectin-1 wurden dabei durch neutralisierende Antikörper oder RNA-Interferenz blockiert.
Ausgekeimte Stadien von A. fumigatus sowie R. arrhizus induzierten eine erhöhte ROS-Freisetzung in Neutrophilen, die durch isolierte oder kombinierte Blockade von TLR2, TLR4 und Dectin-1 abgeschwächt wurde. Ebenso wurde die Phagozytoseaktivität neutrophiler Granulozyten gegenüber R. arrhizus-Konidien durch Blockade von TLR4 und Dectin-1 deutlich reduziert.
Im Gegensatz zu A. fumigatus induzierten sowohl ruhende Konidien als auch ausgekeimte Stadien (Keimschläuche und Hyphen) von R. arrhizus eine robuste pro-inflammatorische Zytokinantwort durch moDCs. Nach Inhibition der Dectin-1 Expression durch RNA-Interferenz zeigte sich die Transkription und Sekretion von Interleukin-1β in Gegenwart aller drei untersuchten Morphotypen von
R. arrhizus deutlich vermindert (Transkription um 46 bis 68 % und Sekretion um 75 bis 79 % vermindert). Diese Ergebnisse legen nahe, dass Dectin-1 ein wichtiger Mediator bei der Einleitung der innaten Immunantwort verschiedener Zelltypen gegen R. arrhizus ist. Diese Beobachtung sollte in weiteren Studien eingehender untersucht werden, z. B. um die Eignung von Dectin-1 als Rezeptor für zelltherapeutische Ansätze wie T-Zell-Konstrukte mit chimären Antigen-Rezeptoren zu evaluieren.
Osteoporose wird definiert als erworbene, generalisierte Skeletterkrankung, die durch eine verminderte Knochenfestigkeit und einen pathologischen Knochenverlust charakterisiert wird. Durch die Störung der Mikroarchitektur kommt es zu strukturellen und funktionellen Defiziten im Sinne von Fragilitätsfrakturen. Mechanische Stimulation erhält die Gewebemasse und stimuliert deren kontinuierliche Anpassung. Östrogene spielen bei der Entwicklung, dem Wachstum und der Regeneration des Knochens eine bedeutende Rolle und wirken über Bindung an die Östrogenrezeptoren ER und ER in bestimmten Zielgeweben. Östrogenrezeptoren sind unverändert sehr geeignete Targets für die Entwicklung von Medikamenten im Rahmen der Osteoporosetherapie wie z.B. die selektiven Östrogen-Rezeptor-Modulatoren (SERMs). Die molekulare Klärung der Einflüsse von ER und ER ist unverändert von großer klinischer Bedeutung. Die Herstellung stabiler Zelllinien mit Überexpression von Reportergenkonstrukten und Rezeptoren kann dabei hilfreich sein. In dieser Arbeit wurde eine stabile Zelllinie mit Überexpression von ERβ etabliert, die unterschiedliche Wirkung von ER und ER wurden analysiert und die Effekte von zyklischer Dehnung auf Reportergenexpression unter der Kontrolle von mechanosensitiven responsiven Elementen wurden charakterisiert.
Seit mehr als zwei Jahrzehnten ist bekannt, dass nicht nur der Tumor Nekrose Faktor-α (=TNF-α) sondern auch Lymphotoxin-α (=LTα) in Form von Trimeren an TNFR1 und TNFR2 binden kann. Durch diese Fähigkeit an beide Rezeptoren zu binden, haben diese zwei Liganden eine essentielle Rolle in der Entwicklung und dem Verlauf von Autoimmunerkrankungen. Bereits mit Beginn der 1990er Jahren wurde gezeigt, dass LTα nicht nur in Form von Homotrimeren vorliegt, sondern auch mit dem verwandten TNF-Superfamilie Liganden Lymphotoxin β (=LTβ) Heterotrimere bilden kann. Hierbei lagern sich LTα und LTβ in Form von LTα2β und LTαβ2 zusammen. Die initialen Experimente mit diesen Heterotrimeren zeigten bereits Unterschiede von LTα2β und LTαβ2. Während LTα2β wie LTα an den TNFR1 bindet, kann LTαβ2 weder an TNFR1 noch TNFR2 binden und interagiert mit einem eigenen Rezeptor namens Lymphotoxin β Rezeptor (=LTβR). Da bereits zwei Liganden (TNF und LTα) für TNFR1 und TNFR2 bekannt waren, wurde LTα2β bis heute nicht weiter charakterisiert. LTαβ2 hingegen war lange Zeit der einzige bekannte Ligand für den LTβR, weshalb die LTαβ2-LTβR-Interaktion ausführlich untersucht wurde.
Diese Arbeit fokusiert sich auf die Charakterisierung von LTα2β. Hierfür wurde die einzige bekannte Eigenschaft aus den 90er Jahren von LTα2β nämlich die Bindung an TNFR1 aufgegriffen und um die Rezeptoren TNFR2 und LTβR erweitert. Diese Arbeit zeigt, dass LTα2β nicht nur an den TNFR1, sondern auch an TNFR2 und schwach an LTβR bindet. Trotz der asymmetrischen Bindestellen kann membrangebundenes LTα2β TNFR1 und TNFR2 nicht nur binden, sondern ist auch in der Lage diese zu aktivieren. Diese Arbeit gibt erste Einblicke in die Komplexizität dieses Heterotrimers indem gezeigt wird, dass LTα2β sowohl in seiner löslichen als auch in seiner membrangebundenen Form den TNFR1 aktivieren kann, während der TNFR2 nur durch das membranständige LTα2β aktiviert wird. Aufgrund der aktivierenden Eigenschaften von membranständigem LTα2β und LTαβ2 auf die murine (=mu) Panc02-Zelllinie wird ein ersten Ausblick auf mögliche weitergehende Experimente in mausbasierten Modellen gegeben. Die erzielten Ergebnisse zeigen, dass mit membranständigem LTα2β ein neuer TNFR2 Agonist gefunden wurde.
Bisherige per Tissue Engineering hergestellte Testsysteme der Mundschleimhaut basieren in der Regel auf allogenen und teils dysplastischen Keratinozyten. Dies schmälert die Aussagekraft der gewonnenen Ergebnisse hinsichtlich des Anspruchs, Nativgewebe bestmöglich nachzubilden.
In der vorliegenden Arbeit sollte daher ein am Lehrstuhl für Tissue Engineering und Regenerative Medizin entwickeltes Protokoll zur Herstellung dreidimensionaler epidermaler Oralmukosaäquivalente auf Basis autologer Keratinozyten auf seine Eigenschaften und Einsatzmöglichkeit als in-vitro Testsystem untersucht werden.
Nach erfolgreicher Isolierung und Kultivierung im Monolayer konnten insgesamt 420 Modelle zu drei verschiedenen Zeitpunkten (Passagen) aufgebaut werden. Die Untersuchung von Histologie, Viabilität und Barrierefunktion mittels MTT, TEER und Natriumfluoresceinpermeabilität konnte einen suffizienten Aufbau von verhorntem, mehrschichtigen oralen Plattenepithel nachweisen. Gleichzeitig konnte eine Abnahme der Epithelqualität mit steigendem Keratinozytenalter festgestellt werden.
Eine sich anschließende Untersuchung von 14 Cytokeratinen sowie Apoptosemarkern per effizienzkorrigierter und normalisierter RT-qPCR konnte die Überlegenheit der dreidimensionalen autologen Oralmukosaäquivalente gegenüber der zweidimensionalen Monolayerkultur auf Genebene zeigen.
Charakterisierung von Patienten mit pulmonaler Hypertonie als Folge einer Linksherzerkrankung
(2021)
Pulmonale Hypertonie (PH) als Folge einer Linksherzerkrankung ist die häufigste Form der PH. Die Identifikation des klinischen Phänotyps der Erkrankung ist oft herausfordernd. Im Rahmen dieser Studie wurden anthropometrische, hämodynamische und funktionelle Daten von Patienten, die sich zwischen 2008 und 2015 in der Lungenhochdruckambulanz der Missioklinik Würzburg vorstellten und ein komplettes diagnostisches Work-Up entsprechend der ESC/ERS Leitlinien durchliefen, retrospektiv analysiert.
Zielsetzung
Die Entwicklung von Präventionsstrategien zur Senkung der Morbidität und Mortalität aufgrund von kardiovaskulären Erkrankungen (KVE) in der Bevölkerung stellt eine Hauptaufgabe der Epidemiologie und Public Health Forschung dar.
In den vergangenen 20 Jahren rückte die Hochrisikoprävention im Zuge der Weiterentwicklung der Scoringsysteme für das KVE Hochrisiko-Screening in den Fokus der Leitlinien zur KVE Prävention.
Jedoch sind die größten Erfolge aus einer komplementären Strategie aus Hochrisiko- und Populationsprävention mit Priorität auf der Reduktion der Exposition von Risikofaktoren für KVE in der gesamten Population zu erwarten.
Die Grundvoraussetzung für die Entwicklung effizienter, populationsweiter Präventionsprogramme ist das Verständnis einerseits der Rolle von Risikofaktoren bei der Krankheitsentstehung und andererseits der Bedeutung der Risikofaktoren auf Populationsebene.
Der Populations-assoziierte Risikoanteil (PAF) ist das bevorzugte statistische Maß zur Quantifizierung des Effekts von Risikofaktoren auf Populationsebene, da er neben der Effektstärke eines Risikofaktors auch dessen Prävalenz berücksichtigt.
In der Praxis erfolgt die Berechnung des PAF in multifaktoriellen Situationen mithilfe von Adjustierungsansätzen oder Partialisierungsansätzen.
Partialisierungsansätze, zu denen auch der gemittelt sequenzielle PAF (gsPAF) gehört, erfüllen die Additivitätseigenschaft.
Insbesondere der gsPAF kommt daher in der praktischen Anwendung zunehmend häufiger zum Einsatz.
Das Ziel der vorliegenden Arbeit ist die Charakterisierung des gsPAF am Beispiel der Epidemiologie von KVE.
Methoden
In Projekt 1 erfolgt die theoretische Abgrenzung des gsPAF von anderen Adjustierungs- und Partialisierungsverfahren in Bezug auf Intention, Definition, Modellvoraussetzungen und -annahmen und Interpretation. Diese verschiedenen Konzepte werden in einer einheitlichen mathematischen Symbolik dargestellt, um das Verständnis zu erleichtern und Abweichungen in den Definitionen hervorzuheben. Anschließend wird in Projekt 2 der praktische Vergleich von modellbasierten Punktschätzern vorgenommen. Im Rahmen der Sekundäranalyse der ProsCIS-Studie über den Populationseinfluss von Risikofaktoren auf schlechtes Outcome nach Schlaganfall werden dem gsPAF ein additiver und ein multiplikativer Adjustierungsansatz gegenübergestellt und die Schätzergebnisse hinsichtlich Übereinstimmung der Größenordnung und Rangfolgen analysiert. In Projekt 3 werden im Rahmen einer Simulationsstudie nach dem proof-of-concept-Prinzip die asymptotischen Eigenschaften existierender modellfreier und modellbasierter Schätzer des gsPAF in Verbindung mit resamplingbasierten Konfidenzschätzern in einer Situation mit einem binären Outcome und drei binären Risikofaktoren unter insgesamt 296 Modellsituationen charakterisiert. Dabei wird die Abhängigkeit von der Stichprobengröße, der Prävalenz des Outcomes, der Prävalenz und Effektstärke der Risikofaktoren, der stochastischen Abhängigkeit der Risikofaktoren und ihrer Effekte auf das Outcome, der Vollständigkeit des statistischen Modells sowie des Outcome-Mechanismus untersucht. Abschließend erfolgt in Projekt 4 die Demonstration der gsPAF-Schätzung exemplarisch im Rahmen der Sekundäranalyse des deutschen Arms der EUROASPIRE IV-Studie. Hier wird der Einfluss von Baselinefaktoren auf das Auftreten rekurrenter kardiovaskulärer Ereignisse nach erstmaliger Hospitalisierung auf Populationsebene modelliert. Die Ergebnisse werden anschließend einer umfassenden Methodenkritik unterzogen. Dazu wird die Modellanpassung der Regressionsmodelle überprüft, die Performanz der gsPAF-Schätzung mit Hilfe der zuvor entwickelten Simulationsstudie evaluiert, eine exemplarische Stichprobenumfangsplanung durchgeführt sowie die Angemessenheit der Modellannahmen des gsPAF diskutiert.
Ergebnisse
%Die Möglichkeiten der statistischen Modellierung von PAF sind nahezu unbegrenzt.
Projekt 1: Adjustierungs- und Partialisierungsmethoden beantworten verschiedene Fragestellungen. Dies resultiert aus dem unterschiedlichen Umgang beider Methoden mit Subgruppen, die bezüglich mehrerer Risikofaktoren gleichzeitig exponiert sind, und führt infolgedessen auch zu unterschiedlichen Interpretationen. Der PAF beschreibt den Anteil an der Ereigniswahrscheinlichkeit, der mit dem Vorliegen eines Risikofaktors assoziiert ist. Für den gsPAF muss zusätzlich betont werden, dass der Effekt in Subgruppen mit mehreren Risikofaktoren auf additive Weise zerlegt und der Anteil des Zusammenwirkens der beteiligten Risikofaktoren (Surplus) zu gleichen Anteilen den Risikofaktoren zugewiesen wird.
Dahinter steckt die Annahme, dass dieser Teil nur durch das Zusammenwirken überhaupt entstehen konnte, wofür beide Risikofaktoren gleichermaßen verantwortlich gemacht werden. Im Gegensatz zu Adjustierungsmethoden erfüllen Partialisierungsmethoden zwar die Additivitätseigenschaft, gehen jedoch gleichzeitig mit spezifischen Modellannahmen einher, die Kenntnisse über die kausalen Verläufe der Risikofaktoren voraussetzen. Im Falle des gsPAF ist dies die Annahme, dass unter den betrachteten Risikofaktoren keine hierarchischen Abhängigkeiten herrschen.
Die theoretische Basis des gsPAF ist derzeit nur für dichotome Outcomes umfangreich erarbeitet und deckt hier alle Ansprüche für den Praxiseinsatz ab: Modellfreie und modellbasierte Punktschätzer, zugehörige Varianzschätzer mit und ohne Berücksichtigung von Störgrößen und Konfidenzschätzer stehen zur Verfügung. Mathematische Eigenschaften wie Symmetrie, Dummyeigenschaft, Additivität und (internen) marginalen Rationalität des gsPAF und anderer Partialisierungsansätze wurden erörtert. Die verfügbare Software stellt derzeit nur Ausschnitte des Methodenspektrums zur Schätzung des gsPAF bereit und ist deshalb für den Einsatz in der empirischen Forschung zu KVE nur begrenzt nützlich. Eine erfolgreiche und effiziente Recherche zum gsPAF wird durch die uneinheitliche Verwendung der Fachtermini ''partieller'' und ''gemittelt sequenzieller'' PAF erschwert.
Projekt 2: Der Vergleich von Ergebnissen aus einem Adjustierungsansatz mit Ergebnissen aus einem Partialisierungsansatz ist über den kombinierten PAF möglich, da der unterschiedliche Umgang mit Subgruppen, die bezüglich mehrerer Risikofaktoren gleichzeitig exponiert sind, nicht zum Tragen kommt, solange nur der kombinierte Risikofaktor im statistischen Modell berücksichtigt wird. Anhand des Datenbeispiels der ProsCIS-Studie wurde für diesen Parameter keine Abweichung der Ergebnisse des multiplikativen Ansatzes (Faktor 1,0) und nur eine geringe Abweichung des additiven Ansatzes (Faktor 1,1) vom gsPAF beobachtet. Die Größenordnungen der Schätzwerte einzelner Risikofaktoren sowie deren Summe sind zwischen Adjustierungs- und Partialisierungsmethoden nicht vergleichbar. Die Ergebnisse aus dem multiplikativen Regressionsmodell weichen bis zu einem Faktor von 1,3 von den Schätzwerten des gsPAF ab. Die Abweichungen aus dem additiven Regressionsmodell gehen deutlich darüber hinaus. Der gsPAF liefert nahezu additive Schätzergebnisse, während die Summe der risikofaktorspezifischen Schätzwerte aus den beiden Adjustierungsmethoden den kombinierten PAF übersteigt. Im Gegensatz zu vorangegangenen Studien wird die Rangfolge der Risikofaktoren im Datenbeispiel nicht wesentlich von der Schätzmethode beeinflusst.
Projekt 3: Die Simulationsstudie charakterisiert die modellfreien und modellbasierten Punktschätzer des gsPAF und belegt deren Konsistenz und (asymptotische) Erwartungstreue, sofern das statistische Modell korrekt spezifiziert ist. Es zeigt sich, dass in kleinen Stichproben oder bei kleinen Ereigniswahrscheinlichkeiten der modellbasierte Schätzer erwartungstreu und damit dem modellfreien Schätzer überlegen ist. Die Berechnungszeit des modellbasierten Schätzers steigt jedoch superlinear mit steigender Stichprobengröße und mit steigender Anzahl von Variablen im Regressionsmodell an. Resamplingbasierte Methoden wie Bootstrap Normal, Perzentil und Jackknife eignen sich für die Schätzung von Konfidenzintervallen des gsPAF. Auch hier ist ein superlinearer Anstieg der Berechnungszeit insbesondere in Verbindung mit dem modellbasierten Schätzer mit steigender Stichprobengröße und mit steigender Anzahl der Risikofaktoren im statistischen Modell zu beobachten.
Biologische Interaktionen von Risikofaktoren im Outcome-Mechanismus verändern die Wahrscheinlichkeit für Ereignisse in Subgruppen mit mehreren Risikofaktoren weg von einem stochastisch unabhängigen und hin zu einem stochastisch abhängigen Szenario. Diese Ereigniswahrscheinlichkeiten werden durch die Anpassung der Parameter im binär-logistischen Regressionsmodell angenähert. Modelle ohne Interaktionsterme repräsentieren aus statistischer Sicht immer einen Outcome-Mechanismus mit stochastischer Abhängigkeit. Interaktionsterme sind nur dann als biologische Interaktionen zu interpretieren, wenn der biologische Outcome-Mechanismus korrekt durch die logistische Regressionsfunktion beschrieben wird. Anderenfalls dienen die Interaktionsterme nur der Modellanpassung und spiegeln nicht die An- oder Abwesenheit biologischer Interaktionen wider. Die Vernachlässigung von relevanten Interaktionstermen führt zu ernstzunehmenden Verzerrungen der Modellparameter und infolgedessen zu stark verzerrten gsPAF-Schätzungen. Dies ist jedoch durch eine gewissenhafte Überprüfung der Modellanpassung während der Auswertung vermeidbar. Grundsätzlich liefert die modellbasierte Schätzung des gsPAF mit allen Interaktionstermen immer unverzerrte Ergebnisse.
Die benötigte Stichprobengröße für eine aussagekräftige Schätzung des gsPAF übersteigt die für relative Maße und steigt mit der Anzahl zu betrachtender Variablen im Modell und mit sinkender Prävalenz des Outcomes an. Während für den PAF steigende Effektgrößen der Risikofaktoren die benötigte Stichprobengröße verkleinern, wurde in der Simulationsstudie ein umgekehrter Zusammenhang für den gsPAF beobachtet.
Projekt 4: Die in den Projekten 1 und 3 gewonnenen Erkenntnisse wurden im Rahmen der Datenanalyse der EUROASPIRE IV-Studie am Praxisbeispiel untersucht und diskutiert. Das Regressionsmodell ohne Interaktionsterme lieferte verzerrte gsPAF-Schätzungen, was durch die Berücksichtigung von Interaktionstermen korrigiert werden konnte. Die resamplingbasierten Konfidenzintervalle überdeckten große Teile des Wertebereiches des gsPAF und liefern somit keine nützlichen Informationen für die epidemiologische Interpretation der Studienergebnisse. Die Validierung der gsPAF-Schätzungen mit Hilfe der Simulationsstudie machte auf die mangelnde Performanz der Punkt- und Konfidenzintervalle aufgrund der verhältnismäßig kleinen Stichprobengröße für die betrachtete Anzahl der Risikofaktoren aufmerksam. Die benötigte Stichprobengröße für eine performante Schätzung des gsPAF in einer Datensituation wie in der EUROASPIRE IV-Studie beobachtet wurde mit Hilfe der Simulationsstudie ermittelt.
Dabei wurde deutlich, dass etwa das Zehnfache der vorliegenden Stichprobengröße benötigt würde, um den modellfreien Schätzer des gsPAF zusammen mit resamplingbasierten Konfidenzintervallen mit einer ausreichenden Performanz schätzen zu können.
Da unter den in EUROASPIRE IV betrachteten Risikofaktoren hierarchische Abhängigkeiten vorliegen könnten, sind die Voraussetzungen für die Schätzung des gsPAF nicht erfüllt. Anstelle des gsPAF könnte im vorliegenden Beispiel ein adjustierter Schätzer zum Einsatz kommen, oder, sofern genügend Informationen über die kausalen Zusammenhänge unter den Risikofaktoren vorliegen, auch sequenzielle oder proportionale Partialisierungsansätze. Die durchgeführte Methodenkritik in Projekt 4 ermöglicht es, weitere Schritte zur Steigerung der Aussagekraft der Studienergebnisse zu unternehmen, beispielsweise durch die Wahl geeigneter statistischer Methoden und die Erhöhung des Stichprobenumfangs.
Schlussfolgerungen
Die Grundvoraussetzungen für die Gewinnung qualitativ hochwertiger Daten sind bekanntermaßen die Wahl eines der Forschungsfrage angemessenen Studiendesigns sowie die sorgfältige Studienplanung. Aufgrund der hohen Anzahl der Risikofaktoren und Störgrößen für kardiovaskuläre Erkrankungen sowie der Komplexität ihrer kausalen Verläufe erfordern Beobachtungsstudien zu KVE große Stichproben, um eine unverzerrte und valide Schätzung der Effekte von Risikofaktoren zu ermöglichen.
Doch die gewonnenen Erkenntnisse eignen sich nur dann für Schlussfolgerungen im epidemiologischen und Public Health Kontext dann, wenn auch die statistische Analyse der Studiendaten mit einer ebenso hohen Qualität erfolgt.
Eine qualitativ hochwertige Datenanalyse zeichnet sich aus durch
(1) die Auswahl der statistischen Methoden passend zur Forschungsfrage,
(2) die Berücksichtigung aktueller methodischer Forschungsergebnisse,
(3) die sorgfältige Überprüfung der Modellannahmen und Modellanpassung,
(4) die Sicherstellung und Überprüfung einer guten Performanz der Punkt- und Konfidenzschätzer und
(5) die realistische Interpretation der Ergebnisse unter Berücksichtigung der Modellvoraussetzungen und -annahmen.
Ein gewissenhafter Umgang mit den statistischen Methoden ist erforderlich, um belastbare Schlussfolgerungen aus Beobachtungsstudien ziehen zu können. Dies gilt insbesondere im Kontext von Sekundärdatenanalysen, die einen beträchtlichen Anteil der Publikationen darstellen. Simulationsstudien sind ein schlagkräftiges Werkzeug für die Validierung der verwendeten statistischen Methoden und ermöglichen die Einschätzung des Informationsgehaltes von Analyseergebnissen. Sie sind ausgesprochen flexibel und lassen sich an beliebige Datensituationen anpassen. Das macht sie zu einem unverzichtbaren Qualitätskriterium für die Publikation empirischer Studien. Jeder Validierungsschritt trägt wesentlich zu einer verbesserten Qualität der Publikationen bei. Damit entsteht eine solide Basis, um die kausalen Verläufe der Risikofaktoren aufzudecken und die Entwicklung von Präventionsprogrammen zur Verbesserung des Gesundheitsstatus in der Population durch Reduktion der Morbidität und Mortalität von KVE voranzubringen.
Ziel der prospektiven, klinischen und monozentrischen Beobachtungsstudie war es, die Eigenschaften der durch die DC/TMD (Diagnostic Criteria for Temporomandibular Disorders) eingeführten neuen Schemata der Schmerzzeichnung für Patienten mit Gesichtsschmerzen zu untersuchen. Der Fokus lag dabei zum einen auf der Reliabilität der Schmerzzeichnung sowie auf der Korrelation mit dem Grad der Schmerzchronifizierung und einer potentiellen psychischen Störung.
218 Patienten mit orofazialen Schmerzen wurden konsekutiv rekrutiert und bearbeiteten einen Fragebogen mit GCPS V.2, PHQ-9 und der Schmerzzeichnung. Eine Untergruppe füllte den Fragebogen nach einer fünfwöchigen Akupunkturtherapie zur Erhebung einer möglichen Veränderung der Schmerzintensität erneut aus. Eine weitere Untergruppe bearbeitete die Fragebögen erneut am selben Tag. Mit einem mehrschrittigen Auswertungsverfahren wurden alle Schmerzzeichnungen ausgewertet.
Die Studienpopulation bestand mit 77,1% aus weiblichen Patienten. Für 44,5% der Kohorte ergab sich eine durch orofaziale Schmerzen bedingte Beeinträchtigung. Die Auswertungsmethoden der Schmerzzeichnung ergaben starke geschlechtsspezifische Unterschiede. Das laterale Kopfschema wies sowohl für Frauen als auch für Männer mit Schmerzbeeinträchtigung signifikant mehr markierte Regionen auf im Vergleich zu Patienten ohne Schmerzbeeinträchtigung. Männer mit dysfunktionalen Schmerzen zeigten zudem eine signifikant höhere prozentual markierte Schmerzoberfläche. Für die männlichen Patienten zeigte sich außerdem für die Anzahl der Regionen und die prozentuale Markierung einen signifikanten Zusammenhang mit einer depressiven Störung. Für Frauen konnten diesbezüglich kein Zusammenhang festgestellt werden und auch der modifizierte Ransford-Score stellte für beide Geschlechter kein valides Screeninginstrument dar, um psychische Beeinträchtigungen zu identifizieren. Die Wiederholungszuverlässigkeit der Schmerzzeichnung war signifikant hoch für das Kopfschema und das intraorale Schema, nicht aber für das Ganzkörperschema.
Insgesamt erwiesen sich die neuen Schemata der Schmerzzeichnung im Rahmen einer CMD Diagnostik als vorteilhaft. Das Geschlecht des Patienten, schmerzbedingte Funktionsstörungen sowie psychische Beeinträchtigungen beeinflussen die durch die Schmerzzeichnung erzielten Ergebnisse unterschiedlich und bestätigen eine vielschichtige Ätiologie der Erkrankung. Die Ergebnisse verweisen zudem auf die Relevanz einer getrennten Betrachtung der Geschlechter in zukünftigen Studien mit orofazialen Schmerzpatienten. Die Summe aller Regionen des Kopfschemas von lateral könnte hinsichtlich der Einschätzung des Ausmaßes einer Schmerzchronifizierung künftig als Auswertungskriterium der Schmerzzeichnung Anwendung finden.
The charged aerosol detector (CAD) is an aerosol-based detector employed in liquid chromatography which has become established in the field of pharmaceutical analysis due to its outstanding performance characteristics, e.g. the almost uniform response for nonvolatile analytes. Owing to its principle of detection, the response of the CAD depends on the volatility of a compound and is inherently nonlinear. However, the newly implemented instrumental settings evaporation temperature and power function value (PFV) are valuable tools to overcome some of these drawbacks and can even enhance the detector’s capabilities when adjusted properly.
This thesis aimed to evaluate the impact of the new instrumental settings on the CAD performance. Additionally, the influence of modern separation techniques for small polar compounds on the CAD was assessed and the applicability of hyphenated UV-CAD techniques explored. The optimization strategies derived from the evaluation procedures and the conjunction of the instrumental and chromatographic techniques investigated were utilized for the challenging impurity profiling of amino acids and amino acid-like drugs.
The results of the method validation procedures confirmed the broad applicability of the CAD in the pharmaceutical analysis of nonvolatile compounds, supported by satisfactory sensitivity and reproducibility for meeting the regulatory requirements with respect to the ICH guidelines Q2(R1) and Q3A(R2). The limits of applicability include the analysis of semivolatile compounds, and the method transfer between current and legacy CAD models. Further advances in the definition and standardization of allowed ranges for the instrumental settings and the establishment of general optimization procedures in the method development could lead to a more widespread use of the detection technique in compendial methods.
The charged aerosol detector (CAD) is the latest representative of aerosol-based detectors that generate a response independent of the analytes' chemical structure. This study was aimed at accurately predicting the CAD response of homologous fatty acids under varying experimental conditions. Fatty acids from C12 to C18 were used as model substances due to semivolatile characterics that caused non-uniform CAD behaviour. Considering both experimental conditions and molecular descriptors, a mixed quantitative structure-property relationship (QSPR) modeling was performed using Gradient Boosted Trees (GBT). The ensemble of 10 decisions trees (learning rate set at 0.55, the maximal depth set at 5, and the sample rate set at 1.0) was able to explain approximately 99% (Q\(^2\): 0.987, RMSE: 0.051) of the observed variance in CAD responses. Validation using an external test compound confirmed the high predictive ability of the model established (R-2: 0.990, RMSEP: 0.050). With respect to the intrinsic attribute selection strategy, GBT used almost all independent variables during model building. Finally, it attributed the highest importance to the power function value, the flow rate of the mobile phase, evaporation temperature, the content of the organic solvent in the mobile phase and the molecular descriptors such as molecular weight (MW), Radial Distribution Function-080/weighted by mass (RDF080m) and average coefficient of the last eigenvector from distance/detour matrix (Ve2_D/Dt). The identification of the factors most relevant to the CAD responsiveness has contributed to a better understanding of the underlying mechanisms of signal generation. An increased CAD response that was obtained for acetone as organic modifier demonstrated its potential to replace the more expensive and environmentally harmful acetonitrile.
Es sollten Checkpoint inhibierende anti-TNFRSF Rezeptor Antikörper-Fusionsproteine hergestellt und charakterisiert werden. Die agonistische Aktivität TNFR-spezifischer Antikörper wird maßgeblich durch eine Immobilisation über Fcγ-Rezeptoren beeinflusst. In dieser Arbeit erfolgte die Immobilisation der Antikörper-Fusionsproteine über den PD-L1. In funktionellen Assays konnte eine Aktivitätssteigerung der TNFR-spezifischen Domänen mittels PD-L1 vermittelter Immobilisation gezeigt werden.
The cuticle is constituted of the biopolymer cutin and intra- and epicuticular waxes. In some cases, it has epicuticular wax crystals, protruding from the epicuticular wax film. One of the most important tasks is protection against desiccation. Many investigations were conducted to find the transport limiting component of the cuticle. It is evidentially confirmed that the waxes form this barrier. These waxes are multifactorial blends made of very-long-chain aliphatic (VLCA) compounds and triterpenoids (TRP). The VLCAs were proposed to constitute the transpiration barrier to water. However, experimental confirmation was lacking so far. The present study focuses on the development of a method to selectively extract TRPs from the cuticle and the impact of the removal on the transpiration barrier.
The plants deployed in this study exhibited several features. They had no epicuticular crystals on their surfaces, were astomatous, had a rather durable and possibly isolatable cuticle. A broad range of wax compositions was covered from plants with no TRP content and low wax load like Hedera helix and Zamioculcas zamiifolia to plants with high TRP content and high wax load like Nerium oleander. The selective extraction was conducted using a sequence of solvents. TRPs were extracted almost exhaustively from CMs with the first MeOH extract. Only a minor amount of shorter chained VLCAs was obtained. The remaining waxes, consisting mostly of VLCAs and some remnant TRPs, were removed with the following TCM extract.
After the extractions, the water permeance of native cuticular membranes (CM), MeOH extracted (M) and dewaxed cuticular discs (MX) was investigated gravimetrically. Compared to the water permeance of CMs, Ms showed no or only a small increase in water conductance. MXs, however, always showed strongly increased values.
The knowledge about the wax compounds constituting the transport-limiting properties is vital for different projects. For various issues, it would be favourable to have a standardized wax mixture as an initial point of research. It could be used to develop screening procedures to investigate the impact of adjuvants on cuticular waxes or the influence of wax constituents on the properties of cuticular waxes. This work concentrated on the development of an artificial wax mixture, which mimics the physical properties of a plant leaf wax sufficiently.
As target wax, the leaf wax of Schefflera elegantissima was chosen. The wax of this plant species consisted almost exclusively of VLCAs, had a rather simple composition regarding compound classes and chain length distribution and CMs could be isolated. Artificial binary, ternary and quaternary waxes corresponding to the conditions within the plant wax were investigated using differential scanning calorimetry (DSC), X-ray diffraction (XRD) techniques and Fourier-transform infrared (FTIR) spectroscopy. Phase diagrams were mapped out for a series of binary, ternary and quaternary wax mixtures. FTIR experiments were conducted using, ternary and a quaternary artificial wax blends. The blends were chosen to represent the conditions within the wax of the adaxial CM plant wax. The FTIR experiments exhibited an increasing resemblance of the artificial wax to the plant wax (adaxial CM wax) with an increasing number of compounds in the artificial wax. The same trend was found for DSC thermograms. Thermograms of ternary and quaternary blends exhibited more overlapping peaks and occurred in a temperature range more similar to the range of the whole leaf plant wax. The XRD spectrum at room temperature showed good conformity with the quaternary blend.
The current work illustrates a method for selective extraction of TRPs from isolated CMs. It gives direct experimental proof of the association of the water permeance barrier with the VLCA rather than to the TRPs. Furthermore, the possibility to mimic cuticular waxes using commercially available wax compounds is investigated. The results show promising feasibility for its viability, enabling it to perform as a standardized initial point for further research (e.g. to examine the influence of different constituents on waxes), revealing valuable knowledge about the structure and the chemistry-function relationship of cuticular waxes.
Within this PhD thesis, chromophore-bridged biradicals were synthesised and their properties characterised. Therefore, it was necessary to develop novel synthetic procedures and implement several experimental characterisation methods. In summary, within this thesis the scope of pigment chromophore phenoxyl radical decoration was further explored and expanded to IIn as well as DPP colourants. HOMA analysis highlighted the importance of aromaticity in order to understand the spin crossover from heteroaromatic quinoidal to aromatic open shell DPPs. Finally, PBI, IIn and DPP biradicals were advanced towards stable materials by introduction of nitronyl nitroxide radical centres.
Purpose
Integrating moderate hypofractionation to the macroscopic tumor with elective nodal irradiation while sparing the organs at risk (OAR) in chemoradiotherapy of locally advanced non-small-cell lung cancer.
Methods
From 2010-2018, treatment, patient and tumor characteristics of 138 patients from two radiation therapy centers were assessed. Chemoradiotherapy by intensity-modulated radiation therapy (IMRT) with a simultaneous integrated boost (SIB) to the primary tumor and macroscopic lymph node metastases was used.
Results
A total of 124 (90%) patients received concurrent chemotherapy. 106 (76%) patients had UICC (Union for International Cancer Control) stage ≥IIIB and 21 (15%) patients had an oligometastatic disease (UICC stage IV). Median SIB and elective total dose was 61.6 and 50.4 Gy in 28 fractions, respectively. Furthermore, 64 patients (46%) had an additional sequential boost to the primary tumor after the SIB-IMRT main series: median 6.6 Gy in median 3 fractions. The median cumulative mean lung dose was 15.6 Gy (range 6.2-29.5 Gy). Median follow-up and radiological follow-up for all patients was 18.0 months (range 0.6-86.9) and 16.0 months (range 0.2-86.9), respectively. Actuarial local control rates at 1, 2 and 3 years were 80.4, 68.4 and 57.8%. Median overall survival and progression-free survival was 30.0 months (95% confidence interval [CI] 23.5-36.4) and 12.1 months (95% CI 8.2-16.0), respectively. Treatment-related toxicity was moderate. Radiation-induced pneumonitis grade 2 and grade 3 occurred in 13 (9.8%) and 3 (2.3%) patients.
Conclusions
Chemoradiotherapy using SIB-IMRT showed promising local tumor control rates and acceptable toxicity in patients with locally advanced and in part oligometastatic lung cancer. The SIB concept, resulting in a relatively low mean lung dose, was associated with low numbers of clinically relevant pneumonitis. The overall survival appears promising in the presence of a majority of patients with UICC stage ≥IIIB disease.
This doctoral thesis is part of a research project on the development of the cognitive compre-hension of film at Würzburg University that was funded by the German Research Foundation (Deutsche Forschungsgemeinschaft) between 2013 and 2019 and awarded to Gerhild Nied-ing. That project examined children’s comprehension of narrative text and its development in illustrated versus non-illustrated formats. For this purpose, van Dijk and Kintsch’s (1983) tri-partite model was used, according to which text recipients form text surface and textbase rep-resentations and construct a situation model. In particular, predictions referring to the influ-ence of illustrations on these three levels of text representation were derived from the inte-grated model of text and picture comprehension (ITPC; Schnotz, 2014), which holds that text-picture units are processed on both text-based (descriptive) and picture-based (depictive) paths. Accordingly, illustrations support the construction of a situation model. Moreover, in line with the embodied cognition account (e.g., Barsalou, 1999), it was assumed that the situa-tion model is grounded in perception and action; text recipients mentally simulate the situation addressed in the text through their neural systems related to perception (perceptual simulation) and action (motor resonance). Therefore, the thesis also examines whether perceptual simula-tion takes place during story reception, whether it improves the comprehension of illustrated stories, and whether motor resonance is related to the comprehension of text accompanied by dynamic illustrations. Finally, predictions concerning the development of comprehending illus-trated text were made in line with Springer’s (2001) hypotheses according to which younger children, compared with older children and adults, focus more on illustrations during text comprehension (perceptual boundedness) and use illustrations for the development of cogni-tive skills (perceptual support).
The first research question sought to validate the tripartite model in the context of children’s comprehension of narrative text, so Hypothesis 1 predicted that children yield representations of the text surface, the textbase, and the situation model during text reception. The second research question comprised the assumptions regarding the impact of illustrations on text comprehension. Accordingly, it was expected that illustrations improve the situation model (Hypothesis 2a), especially when they are processed before their corresponding text passages (Hypothesis 2b). Both hypotheses were derived from the ITPC and the assumption that per-ceptual simulation supports the situation model. It was further predicted that dynamic illustra-tions evoke more accurate situation models than static ones (Hypothesis 2c); this followed from the assumption that motor resonance supports the situation model. In line with the ITPC, it was assumed that illustrations impair the textbase (Hypothesis 2d), especially when they are presented after their corresponding text passages (Hypothesis 2e). In accordance with earlier results, it was posited that illustrations have a beneficial effect for the text surface (Hypothesis 2f). The third research question addressed the embodied approach to the situation model. Here, it was assumed that perceptual simulation takes place during text reception (Hypothesis 3a) and that it is more pronounced in illustrated than in non-illustrated text (Hypothesis 3b); the latter hypothesis was related to a necessary premise of the assumption that perceptual sim-ulation improves the comprehension of illustrated text. The fourth research question was relat-ed to perceptual boundedness and perceptual support and predicted age-related differences; younger children were expected to benefit more from illustrations regarding the situation model (Hypothesis 4a) and to simulate vertical object movements in a more pronounced fash-ion (Hypothesis 4b) than older children. In addition, Hypothesis 4c held that perceptual simu-lation is more pronounced in younger children particularly when illustrations are present.
Three experiments were conducted to investigate these hypotheses. Experiment 1 (Seger, Wannagat, & Nieding, submitted).compared the tripartite representations of written text without illustrations, with illustrations presented first, and with illustrations presented after their corresponding sentences. Students between 7 and 13 years old (N = 146) took part. Ex-periment 2 (Seger, Wannagat, & Nieding, 2019) investigated the tripartite representations of auditory text, audiovisual text with static illustrations, and audiovisual text with dynamic il-lustrations among children in the same age range (N = 108). In both experiments, a sentence recognition method similar to that introduced by Schmalhofer and Glavanov (1986) was em-ployed. This method enables the simultaneous measurement of all three text representations. Experiment 3 (Seger, Hauf, & Nieding, 2020) determined the perceptual simulation of vertical object movements during the reception of auditory and audiovisual narrative text among chil-dren between 5 and 11 years old and among adults (N = 190). For this experiment, a picture verification task based on Stanfield and Zwaan’s (2001) paradigm and adapted from Hauf (2016) was used.
The first two experiments confirmed Hypothesis 1, indicating that the tripartite model is appli-cable to the comprehension of auditory and written narrative text among children. A benefi-cial effect of illustrations to the situation model was observed when they were presented syn-chronously with auditory text (Hypotheses 2a), but not when presented asynchronously with written text (Hypothesis 2b), so the ITPC is partly supported on this point. Hypothesis 2c was rejected, indicating that motor resonance does not make an additional contribution to the comprehension of narrative text with dynamic illustrations. Regarding the textbase, a general negative effect of illustrations was not observed (Hypothesis 2d), but a specific negative effect of illustrations that follow their corresponding text passages was seen (Hypothesis 2e); the latter result is also in line with the ITPC. The text surface (Hypothesis 2f) appears to benefit from illustrations in auditory but not written text. The results obtained in Experiment 3 sug-gest that children and adults perceptually simulate vertical object movements (Hypothesis 3a), but there appears to be no difference between auditory and audiovisual text (Hypothesis 3b), so there is no support for a functional relationship between perceptual simulation and the situ-ation model in illustrated text. Hypotheses 4a–4c were investigated in all three experiments and did not receive support in any of them, which indicates that representations of illustrated and non-illustrated narrative text remain stable within the age range examined here.
The Vacaciones en Paz programme (VeP) started in 1979 shortly after Morocco illegally occupied Western Sahara, which since 1975 has been a disputed territory pending a referendum for self-determination. The programme consists of Sahrawi children being hosted during summer by Spanish families who try to raise awareness for the Sahrawi cause and temporarily alleviate the children’s living conditions. Meanwhile, approximately 170,000 Sahrawi refugees live in camps near Tindouf (Algeria) heavily dependent on humanitarian aid for their survival.
This study aimed to determine the impact of the VeP programme on the promotion of children’s rights based on the perspective of Sahrawi children. Research has shown that it serves as a temporary platform to implement some of those rights. This qualitative study is based on a literature review of the principles of the VeP programme, alongside a thematic analysis of the field data provided by Sahrawi children and teenagers. Analysis of the VeP programme demonstrated that the Convention of the Rights of the Child is not mentioned in its discourse. Notwithstanding, the results indicate an impact on the promotion of Sahrawi children’s rights. On this basis, it is recommended to implement a children’s rights-based discourse within the principles of the VeP programme, since the theoretical knowledge of their rights may be a key factor for strategic empowerment of Sahrawi children and teenagers in their representation of the Sahrawi cause.
According to the tripartite model of text representation (van Dijk & Kintsch, 1983), readers form representations of the text surface and textbase, and construct a situation model. In this study, an experiment was conducted to investigate whether these levels of representation would be affected by adding illustrations to narrative text and whether the order of text and illustrations would make a difference. Students aged between 7 and 13 years (N = 146) read 12 narrative texts, 4 of them with illustrations presented before their corresponding sentences, 4 with illustrations presented after, and 4 without any illustration. A sentence recognition task was used to assess the accuracy for text surface, textbase, and situation model. For the text surface and situation model, neither the presence of illustrations nor the order of text and illustrations influenced accuracy. However, the textbase was negatively affected by illustrations when they followed their corresponding sentences. We suggest that illustrations can initiate model inspection after situation model construction (Schnotz, 2014), a process that can make substantial changes to the textbase representation.
Chimeric antigen receptor (CAR)-modified T cells targeting FLT3 in acute myeloid leukemia (AML)
(2021)
Adoptive immunotherapy using chimeric antigen receptor (CAR)-modified T cells targeting CD19 has shown remarkable therapeutic efficacy against B cell leukemia and lymphoma, and provided proof of concept for therapeutic potential in other hematologic malignancies. Acute myeloid leukemia (AML) is an entity with an unmet medical need for effective and curative treatments. Therefore, there is a strong desire for development of potentially curative CAR-T cell immunotherapy for AML treatment.
FMS-like tyrosine kinase 3 (FLT3) is a homodimeric transmembrane protein expressed uniformly by AML blasts. FLT3 plays a vital role in the survival of AML blasts and is a key driver of leukemia-genesis in AML cases with internal tandem duplication (FLT3ITD) and tyrosine kinase domain (TKD) mutations. These attributes suggest that FLT3 could be an excellent target for CAR-T cell immunotherapy. Here, we engineered human CD4+ and CD8+ T cells to express FLT3-specific CARs and demonstrate that they confer potent reactivity against AML cell lines and primary AML blasts that express either wild-type FLT3 or FLT3-ITD. Further, we show that FLT3 CAR-T cells exert potent antileukemia activity in xenograft models of AML and induce complete remissions.
We also demonstrate that FLT3-expression on FLT3-ITD+ AML cells can be augmented by FLT3 inhibitors, which lead to increased recognition by CARs and improved efficacy of FLT3 CAR-T cells. We confirmed this principle with three different FLT3 inhibitors which are at distinct stages of clinical development i.e. Phase II/III clinical trial (crenolanib, quizartinib) and clinically approved (midostaurin). Further, we observed the strongest anti-leukemia activity of FLT3 CAR-T cells in combination with crenolanib in vivo.
FLT3 is known to be expressed by normal hematopoietic stem and progenitor cells. We evaluated FLT3-expression on normal hematopoietic stem cells (HSCs) using flow cytometry and confirmed lower level of FLT3-expression on HSCs and progenitors compared to AML cells. As anticipated, we found that FLT3 CAR-T cells recognize normal HSCs in vitro and in vivo, and compromise normal hematopoiesis, suggesting that adoptive therapy with FLT3 CAR-T cells will require successive CAR-T cell depletion and allogeneic HSC transplantation (HSCT) to reconstitute the hematopoietic system. Moreover, an FLT3 inhibitor treatment does not increase FLT3-expression on HSCs. Accordingly, we demonstrate that the depletion of FLT3 CAR-T cells is possible with inducible Caspase 9 (iCasp9) safety switch.
Collectively, our data establish FLT3 as a novel CAR target in AML with particular relevance in high-risk FLT3-ITD+ AML. Our data demonstrate that FLT3 CAR-T cells act synergistically with FLT3 inhibitors in FLT3-ITD+ AML. i.e. FLT3 inhibitors-induced upregulation of FLT3 in FLT3-ITD+ AML cells enhances their recognition and elimination by FLT3 CAR-T cells. Due to recognition of normal HSCs, the clinical use of FLT3 CART cells is likely restricted to a defined therapeutic window and must be followed by CART cell depletion and allogeneic HSCT for hematopoietic reconstitution. The data provide rational to use FLT3 CAR-T cells in combination with FLT3 inhibitors to augment the anti-leukemia efficacy of FLT3 CAR-T cells in high-risk FLT3-ITD+ AML patients, and to mitigate the risk of relapse with FLT3-negative AML variants, which could otherwise develop under therapeutic pressure. The data provide proof of concept for synergistic use of CAR-T cell immunotherapy and small molecule targeted therapy and encourage the clinical evaluation of this combination treatment in high-risk patients with FLT3-ITD+ AML.
A series of perylene bisimide (PBI) dyes bearing various aryl substituents in 1,6,7,12 bay positions has been synthesized by Suzuki cross-coupling reaction. These molecules exhibit an exceptionally large and conformationally fixed twist angle of the PBI π-core due to the high steric congestion imparted by the aryl substituents in bay positions. Single crystal X-ray analyses of phenyl-, naphthyl- and pyrenyl-functionalized PBIs reveal interlocked π-π-stacking motifs, leading to conformational chirality and the possibility for the isolation of enantiopure atropoisomers by semipreparative HPLC. The interlocked arrangement endows these molecules with substantial racemization barriers of about 120 kJ mol\(^{−1}\) for the tetraphenyl- and tetra-2-naphthyl-substituted derivatives, which is among the highest racemization barriers for axially chiral PBIs. Variable temperature NMR studies reveal the presence of a multitude of up to fourteen conformational isomers in solution that are interconverted via smaller activation barriers of about 65 kJ mol\(^{−1}\). The redox and optical properties of these core-twisted PBIs have been characterized by cyclic voltammetry, UV/Vis/NIR and fluorescence spectroscopy and their respective atropo-enantiomers were further characterized by circular dichroism (CD) and circular polarized luminescence (CPL) spectroscopy.
Chronic obstructive pulmonary disease (COPD) is a major cause of morbidity and mortality worldwide and encompasses chronic bronchitis and emphysema. It has been shown that vascular wall remodeling and pulmonary hypertension (PH) can occur not only in patients with COPD but also in smokers with normal lung function, suggesting a causal role for vascular alterations in the development of emphysema. Mechanistically, abnormalities in the vasculature, such as inflammation, endothelial dysfunction, imbalances in cellular apoptosis/proliferation, and increased oxidative/nitrosative stress promote development of PH, cor pulmonale, and most probably pulmonary emphysema. Hypoxemia in the pulmonary chamber modulates the activation of key transcription factors and signaling cascades, which propagates inflammation and infiltration of neutrophils, resulting in vascular remodeling. Endothelial progenitor cells have angiogenesis capabilities, resulting in transdifferentiation of the smooth muscle cells via aberrant activation of several cytokines, growth factors, and chemokines. The vascular endothelium influences the balance between vaso-constriction and -dilation in the heart. Targeting key players affecting the vasculature might help in the development of new treatment strategies for both PH and COPD. The present review aims to summarize current knowledge about vascular alterations and production of reactive oxygen species in COPD. The present review emphasizes on the importance of the vasculature for the usually parenchyma-focused view of the pathobiology of COPD.
Occupational mold exposure can lead to Aspergillus-associated allergic diseases including asthma and hypersensitivity pneumonitis. Elevated IL-17 levels or disbalanced T-helper (Th) cell expansion were previously linked to Aspergillus-associated allergic diseases, whereas alterations to the Th cell repertoire in healthy occupationally exposed subjects are scarcely studied. Therefore, we employed functional immunoassays to compare Th cell responses to A. fumigatus antigens in organic farmers, a cohort frequently exposed to environmental molds, and non-occupationally exposed controls. Organic farmers harbored significantly higher A. fumigatus-specific Th-cell frequencies than controls, with comparable expansion of Th1- and Th2-cell frequencies but only slightly elevated Th17-cell frequencies. Accordingly, Aspergillus antigen-induced Th1 and Th2 cytokine levels were strongly elevated, whereas induction of IL-17A was minimal. Additionally, increased levels of some innate immune cell-derived cytokines were found in samples from organic farmers. Antigen-induced cytokine release combined with Aspergillus-specific Th-cell frequencies resulted in high classification accuracy between organic farmers and controls. Aspf22, CatB, and CipC elicited the strongest differences in Th1 and Th2 responses between the two cohorts, suggesting these antigens as potential candidates for future bio-effect monitoring approaches. Overall, we found that occupationally exposed agricultural workers display a largely balanced co-expansion of Th1 and Th2 immunity with only minor changes in Th17 responses.
Background
Deregulated expression of MYC is a driver of colorectal carcinogenesis, suggesting that decreasing MYC expression may have significant therapeutic value. CIP2A is an oncogenic factor that regulates MYC expression. CIP2A is overexpressed in colorectal cancer (CRC), and its expression levels are an independent marker for long-term outcome of CRC. Previous studies suggested that CIP2A controls MYC protein expression on a post-transcriptional level.
Methods
To determine the mechanism by which CIP2A regulates MYC in CRC, we dissected MYC translation and stability dependent on CIP2A in CRC cell lines.
Results
Knockdown of CIP2A reduced MYC protein levels without influencing MYC stability in CRC cell lines. Interfering with proteasomal degradation of MYC by usage of FBXW7-deficient cells or treatment with the proteasome inhibitor MG132 did not rescue the effect of CIP2A depletion on MYC protein levels. Whereas CIP2A knockdown had marginal influence on global protein synthesis, we could demonstrate that, by using different reporter constructs and cells expressing MYC mRNA with or without flanking UTR, CIP2A regulates MYC translation. This interaction is mainly conducted by the MYC 5′UTR.
Conclusions
Thus, instead of targeting MYC protein stability as reported for other tissue types before, CIP2A specifically regulates MYC mRNA translation in CRC but has only slight effects on global mRNA translation. In conclusion, we propose as novel mechanism that CIP2A regulates MYC on a translational level rather than affecting MYC protein stability in CRC.
Brain-wide neural circuits enable bi- and quadrupeds to express adaptive locomotor behaviors in a context- and state-dependent manner, e.g., in response to threats or rewards. These behaviors include dynamic transitions between initiation, maintenance and termination of locomotion. Advances within the last decade have revealed an intricate coordination of these individual locomotion phases by complex interaction of multiple brain circuits. This review provides an overview of the neural basis of state-dependent modulation of locomotion initiation, maintenance and termination, with a focus on insights from circuit-centered studies in rodents. The reviewed evidence indicates that a brain-wide network involving excitatory circuit elements connecting cortex, midbrain and medullary areas appears to be the common substrate for the initiation of locomotion across different higher-order states. Specific network elements within motor cortex and the mesencephalic locomotor region drive the initial postural adjustment and the initiation of locomotion. Microcircuits of the basal ganglia, by implementing action-selection computations, trigger goal-directed locomotion. The initiation of locomotion is regulated by neuromodulatory circuits residing in the basal forebrain, the hypothalamus, and medullary regions such as locus coeruleus. The maintenance of locomotion requires the interaction of an even larger neuronal network involving motor, sensory and associative cortical elements, as well as defined circuits within the superior colliculus, the cerebellum, the periaqueductal gray, the mesencephalic locomotor region and the medullary reticular formation. Finally, locomotor arrest as an important component of defensive emotional states, such as acute anxiety, is mediated via a network of survival circuits involving hypothalamus, amygdala, periaqueductal gray and medullary premotor centers. By moving beyond the organizational principle of functional brain regions, this review promotes a circuit-centered perspective of locomotor regulation by higher-order states, and emphasizes the importance of individual network elements such as cell types and projection pathways. The realization that dysfunction within smaller, identifiable circuit elements can affect the larger network function supports more mechanistic and targeted therapeutic intervention in the treatment of motor network disorders.
Context
Cushing’s syndrome (CS) is a rare disease of endogenous hypercortisolism associated with high morbidity and mortality. Diagnosis and classification of CS is still challenging.
Objective
Circulating microRNAs (miRNAs) are minimally invasive diagnostic markers. Our aim was to characterize the circulating miRNA profiles of CS patients and to identify distinct profiles between the two major CS subtypes.
Methods
We included three groups of patients from the German Cushing’s registry: ACTH-independent CS (Cortisol-Producing-Adenoma; CPA), ACTH-dependent pituitary CS (Cushing’s Disease; CD), and patients in whom CS had been ruled out (controls). Profiling of miRNAs was performed by next-generation-sequencing (NGS) in serum samples of 15 CS patients (each before and after curative surgery) and 10 controls. Significant miRNAs were first validated by qPCR in the discovery cohort and then in an independent validation cohort of 20 CS patients and 11 controls.
Results
NGS identified 411 circulating miRNAs. Differential expression of 14 miRNAs were found in the pre- and postoperative groups. qPCR in the discovery cohort validated 5 of the significant miRNAs from the preoperative group analyses. Only, miR-182-5p was found to be significantly upregulated in the CD group of the validation cohort. Comparing all CS samples as a group with the controls did not reveal any significant differences in expression.
Outcome
In conclusion, our study identified miR-182-5p as a possible biomarker for CD, which has to be validated in a prospective cohort. Furthermore, our results suggest that presence or absence of ACTH might be at least as relevant for miRNA expression as hypercortisolism itself.
Atmospheric circulation is a vital process in the transport of heat, moisture, and pollutants around the globe. The variability of rainfall depends to some extent on the atmospheric circulation. This paper investigates synoptic situations in southern Africa that can be associated with wet days and dry days in Free State, South Africa, in addition to the underlying dynamics. Principal component analysis was applied to the T-mode matrix (variable is time series and observation is grid points at which the field was observed) of daily mean sea level pressure field from 1979 to 2018 in classifying the circulation patterns in southern Africa. 18 circulation types (CTs) were classified in the study region. From the linkage of the CTs to the observed rainfall data, from 11 stations in Free State, it was found that dominant austral winter and late austral autumn CTs have a higher probability of being associated with dry days in Free State. Dominant austral summer and late austral spring CTs were found to have a higher probability of being associated with wet days in Free State. Cyclonic/anti-cyclonic activity over the southwest Indian Ocean, explained to a good extent, the inter-seasonal variability of rainfall in Free State. The synoptic state associated with a stronger anti-cyclonic circulation at the western branch of the South Indian Ocean high-pressure, during austral summer, leading to enhanced low-level moisture transport by southeast winds was found to have the highest probability of being associated with above-average rainfall in most regions in Free State. On the other hand, the synoptic state associated with enhanced transport of cold dry air, by the extratropical westerlies, was found to have the highest probability of being associated with (winter) dryness in Free State.
Sphingolipids, including ceramides, are a diverse group of structurally related lipids composed of a sphingoid base backbone coupled to a fatty acid side chain and modified terminal hydroxyl group. Recently, it has been shown that sphingolipids show antimicrobial activity against a broad range of pathogenic microorganisms. The antimicrobial mechanism, however, remains so far elusive. Here, we introduce 'click-AT-CLEM', a labeling technique for correlated light and electron microscopy (CLEM) based on the super-resolution array tomography (srAT) approach and bio-orthogonal click chemistry for imaging of azido-tagged sphingolipids to directly visualize their interaction with the model Gram-negative bacterium Neisseria meningitidis at subcellular level. We observed ultrastructural damage of bacteria and disruption of the bacterial outer membrane induced by two azido-modified sphingolipids by scanning electron microscopy and transmission electron microscopy. Click-AT-CLEM imaging and mass spectrometry clearly revealed efficient incorporation of azido-tagged sphingolipids into the outer membrane of Gram-negative bacteria as underlying cause of their antimicrobial activity.
Contemporary climate change leads to earlier spring phenological events in Europe. In forests, in which overstory strongly regulates the microclimate beneath, it is not clear if further change equally shifts the timing of leaf unfolding for the over- and understory of main deciduous forest species, such as Fagus sylvatica L. (European beech). Furthermore, it is not known yet how this vertical phenological (mis)match — the phenological difference between overstory and understory — affects the remotely sensed satellite signal. To investigate this, we disentangled the start of season (SOS) of overstory F.sylvatica foliage from understory F. sylvatica foliage in forests, within nine quadrants of 5.8 × 5.8 km, stratified over a temperature gradient of 2.5 °C in Bavaria, southeast Germany, in the spring seasons of 2019 and 2020 using time lapse cameras and visual ground observations. We explained SOS dates and vertical phenological (mis)match by canopy temperature and compared these to Sentinel-2 derived SOS in response to canopy temperature. We found that overstory SOS advanced with higher mean April canopy temperature (visual ground observations: −2.86 days per °C; cameras: −2.57 days per °C). However, understory SOS was not significantly affected by canopy temperature. This led to an increase of vertical phenological mismatch with increased canopy temperature (visual ground observations: +3.90 days per °C; cameras: +2.52 days per °C). These results matched Sentinel-2-derived SOS responses, as pixels of higher canopy height advanced more by increased canopy temperature than pixels of lower canopy height. The results may indicate that, with further climate change, spring phenology of F. sylvatica overstory will advance more than F. sylvatica understory, leading to increased vertical phenological mismatch in temperate deciduous forests. This may have major ecological effects, but also methodological consequences for the field of remote sensing, as what the signal senses highly depends on the pixel mean canopy height and the vertical (mis)match.
Clinical and biological characteristics of medullary and extramedullary plasma cell dyscrasias
(2021)
Background: Extramedullary plasma cell (PC) disorders may occur as extramedullary disease in multiple myeloma (MM-EMD) or as primary extramedullary plasmocytoma (pEMP)/solitary osseous plasmocytoma (SOP). In this study, we aimed to obtain insights into the molecular mechanisms of extramedullary spread of clonal PC. Methods: Clinical and biological characteristics of 87 patients with MM-EMD (n = 49), pEMP/SOP (n = 20) and classical MM (n = 18) were analyzed by using immunohistochemistry (CXCR4, CD31, CD44 and CD81 staining) and cytoplasmic immunoglobulin staining combined with fluorescence in situ hybridization (cIg-FISH). Results: High expression of CD44, a cell-surface glycoprotein involved in cell-cell interactions, was significantly enriched in MM-EMD (90%) vs. pEMP/SOP (27%) or classical MM (33%) (p < 0.001). In addition, 1q21 amplification by clonal PC occurred at a similar frequency of MM-EMD (33%), pEMP/SOP (57%) and classical MM (44%). Conversely, del(17p13), t(4;14) and t(14;16) were completely absent in pEMP/SOP. Besides this, 1q21 amplification was identified in 64% of not paraskeletal samples from MM-EMD or pEMP compared to 9% of SOP or paraskeletal MM-EMD/pEMP and 44% of classical MM samples, respectively (p = 0.02). Conclusion: Expression of molecules involved in homing and cytogenetic aberrations differ between MM with or without EMD and pEMP/SOP.
Purpose
The ongoing pandemic caused by the novel severe acute respiratory coronavirus 2 (SARS-CoV-2) has stressed health systems worldwide. Patients with chronic kidney disease (CKD) seem to be more prone to a severe course of coronavirus disease (COVID-19) due to comorbidities and an altered immune system. The study’s aim was to identify factors predicting mortality among SARS-CoV-2-infected patients with CKD.
Methods
We analyzed 2817 SARS-CoV-2-infected patients enrolled in the Lean European Open Survey on SARS-CoV-2-infected patients and identified 426 patients with pre-existing CKD. Group comparisons were performed via Chi-squared test. Using univariate and multivariable logistic regression, predictive factors for mortality were identified.
Results
Comparative analyses to patients without CKD revealed a higher mortality (140/426, 32.9% versus 354/2391, 14.8%). Higher age could be confirmed as a demographic predictor for mortality in CKD patients (> 85 years compared to 15–65 years, adjusted odds ratio (aOR) 6.49, 95% CI 1.27–33.20, p = 0.025). We further identified markedly elevated lactate dehydrogenase (> 2 × upper limit of normal, aOR 23.21, 95% CI 3.66–147.11, p < 0.001), thrombocytopenia (< 120,000/µl, aOR 11.66, 95% CI 2.49–54.70, p = 0.002), anemia (Hb < 10 g/dl, aOR 3.21, 95% CI 1.17–8.82, p = 0.024), and C-reactive protein (≥ 30 mg/l, aOR 3.44, 95% CI 1.13–10.45, p = 0.029) as predictors, while renal replacement therapy was not related to mortality (aOR 1.15, 95% CI 0.68–1.93, p = 0.611).
Conclusion
The identified predictors include routinely measured and universally available parameters. Their assessment might facilitate risk stratification in this highly vulnerable cohort as early as at initial medical evaluation for SARS-CoV-2.
Activation of the complement system and leukocytes by blood–membrane interactions may further promote arteriosclerosis typically present in patients on lipoprotein apheresis. As clinical data on the hemocompatibility of lipoprotein apheresis are scarce, a controlled clinical study comparing two different types of plasma separation and fractionation membranes used in double-filtration lipoprotein apheresis was urgently needed, as its outcome may influence clinical decision-making. In a prospective, randomized, crossover controlled trial, eight patients on double-filtration lipoprotein apheresis were subjected to one treatment with recent polyethersulfone (PES) plasma separation and fractionation membranes and one control treatment using a set of ethylene-vinyl alcohol copolymer (EVAL) membranes. White blood cell (WBC) and platelet (PC) counts, complement factor C5a and thrombin–antithrombin III (TAT) concentrations were determined in samples drawn at defined times from different sites of the extracorporeal blood and plasma circuit. With a nadir at 25 minutes, WBCs in EVAL decreased to 33.5 ± 10.7% of baseline compared with 63.8 ± 22.0% at 20 minutes in PES (P < .001). The maximum C5a levels in venous blood reentering the patients were measured at 30 minutes, being 30.0 ± 11.2 µg/L with EVAL and 12.3 ± 9.0 µg/L with PES (P < .05). The highest C5a concentrations were found in plasma after the plasma filters (EVAL 56.1 ± 22.0 µg/L at 15 minutes vs PES 23.3 ± 15.2 µg/L at 10 minutes; P < .001). PC did not significantly decrease over time with both membrane types, whereas TAT levels did not rise until the end of the treatment without differences between membranes. Regarding lipoprotein(a) and low-density lipoprotein (LDL) cholesterol removal, both membrane sets performed equally. Compared with EVAL, PES membranes cause less leukocyte and complement system activation, the classical parameters of hemocompatibility of extracorporeal treatment procedures, at identical treatment efficacy. Better hemocompatibility may avoid inflammation-promoting effects through blood–material interactions in patients requiring double-filtration lipoprotein apheresis.
The interplay between inflammation and oxidative stress is a vicious circle, potentially resulting in organ damage. Essential micronutrients such as selenium (Se) and zinc (Zn) support anti-oxidative defense systems and are commonly depleted in severe disease. This single-center retrospective study investigated micronutrient levels under Se and Zn supplementation in critically ill patients with COVID-19 induced acute respiratory distress syndrome (ARDS) and explored potential relationships with immunological and clinical parameters. According to intensive care unit (ICU) standard operating procedures, patients received 1.0 mg of intravenous Se daily on top of artificial nutrition, which contained various amounts of Se and Zn. Micronutrients, inflammatory cytokines, lymphocyte subsets and clinical data were extracted from the patient data management system on admission and after 10 to 14 days of treatment. Forty-six patients were screened for eligibility and 22 patients were included in the study. Twenty-one patients (95%) suffered from severe ARDS and 14 patients (64%) survived to ICU discharge. On admission, the majority of patients had low Se status biomarkers and Zn levels, along with elevated inflammatory parameters. Se supplementation significantly elevated Se (p = 0.027) and selenoprotein P levels (SELENOP; p = 0.016) to normal range. Accordingly, glutathione peroxidase 3 (GPx3) activity increased over time (p = 0.021). Se biomarkers, most notably SELENOP, were inversely correlated with CRP (r\(_s\) = −0.495), PCT (r\(_s\) = −0.413), IL-6 (r\(_s\) = −0.429), IL-1β (r\(_s\) = −0.440) and IL-10 (r\(_s\) = −0.461). Positive associations were found for CD8\(^+\) T cells (r(_s\) = 0.636), NK cells (r\(_s\) = 0.772), total IgG (r\(_s\) = 0.493) and PaO\(_2\)/FiO\(_2\) ratios (r\(_s\) = 0.504). In addition, survivors tended to have higher Se levels after 10 to 14 days compared to non-survivors (p = 0.075). Sufficient Se and Zn levels may potentially be of clinical significance for an adequate immune response in critically ill patients with severe COVID-19 ARDS.
Background
Right ventricular dysfunction after CABG is associated with poor peri- and postoperative outcomes. We aimed to identify clinical and experimental predictors for preoperative inapparent right ventricular dysfunction and therefore hypothesized that reduced myofilament force development as well as altered levels of biomarkers might predict inapparent right ventricular dysfunction.
Methods
From 08/2016 to 02/2018, 218 patients scheduled for CABG were divided into two groups (TAPSE ≥ 20 mm, n = 178; TAPSE < 20 mm, n = 40). Baseline serum samples for biomarkers (Galectin, TGFß1, N Acyl-SDMA, Arginine, ADMA and Pentraxin-3), clinical laboratory and transthoracic echocardiographic parameters were evaluated. To examine the myocardial apparatus of the right ventricle intraoperative right auricular tissue was harvested for stepwise skinned fiber force measurements.
Results
Patients with TAPSE < 20 mm had a higher incidence of DM (55 vs. 34%, p = 0.018), preoperative AFib (43 vs. 16%, p < 0.001), reduced GFR (67 ± 18 vs. 77 ± 24 ml/min/1.73 m\(^2\), p = 0.013), larger LA area (22 ± 6 vs. 20 ± 5 cm\(^2\), p = 0.005) and reduced LVEF (50 vs. 55%, p = 0.008). Furthermore, higher serum ADMA (0.70 ± 0.13 vs. 0.65 ± 0.15 µmol/l, p = 0.046) and higher serum Pentraxin-3 levels (3371 ± 1068 vs. 2681 ± 1353 pg/dl, p = 0.004) were observed in these patients. Skinned fiber force measurements showed significant lower values at almost every step of calcium concentration (pCa 4.52 to pCa 5.5, p < 0.01 and pCa 5.75–6.0, p < 0.05). Multivariable analysis revealed DM (OR 2.53, CI 1.12–5.73, Euro Score II (OR 1.34, CI 1.02–1.78), preoperative AF (OR 4.86, CI 2.06–11.47), GFR (OR 7.72, CI 1.87–31.96), albumin (OR 1.56, CI 0.52–2.60), Pentraxin-3 (OR 19.68, CI 14.13–25.24), depressed LVEF (OR 8.61, CI 6.37–10.86), lower force values: (pCa 5.4; OR 2.34, CI 0.40–4.29 and pCa 5.2; OR 2.00, CI 0.39–3.60) as predictors for clinical inapparent right heart dysfunction.
Conclusions
These preliminary data showed that inapparent right heart dysfunction in CAD is already associated with reduced force development of the contractile apparatus.
CD4+Foxp3+ Tregs can be induced in vitro by TGF-b stimulation. Here, CNS1 deficient CD4+ T cells were found to show compromised Foxp3 upregulation in vitro compared to CNS1 WT CD4+ T cells. Moreover, we could demonstrate that antigen-specific CD4+Foxp3+ Tregs can be induced in vivo by tolerogenic antigen stimulation. Parenteral application of agonist BDC2.5 mimetope induced Foxp3 expression in CD4+ BDC2.5 tg cells. We could show that induction of Foxp3 expression by tolerogenic peptide stimulation is impaired in CNS1 deficient CD4+ BDC2.5 tg cells compared to CNS1 WT CD4+ BDC2.5 tg controls. These results indeed indicate that in vivo induced Tregs share mechanistic characteristics with naturally occurring pTregs.
Additional in vivo experiments with blocking monoclonal anti-TGF-b demonstrated that high dosage TGF-b blockade abrogated peptide-induced Foxp3 expression in CNS1 WT BDC2.5 tg CD4+ cells, akin to what is seen for impaired Foxp3 upregulation in peptide-stimulated CNS1 KO BDC2.5 tg CD4+ cells without anti-TGF-b-treatment.
Adoptive transfer of CD4+CD25- T cells in T cell deficient recipients dramatically increased CD4+Foxp3+ Treg frequencies in both CNS1 WT CD4+ and CNS1 KO CD4+ donor cells. Despite an initially lower increase in Foxp3 expression in CNS1 KO donor cells compared to CNS1 WT donor cells early after transfer, in this setting impaired Treg induction in CNS1 deficient cells was not preserved over time. Consequently, diabetes onset and progression were indistinguishable between mice that received CNS1 WT or CNS1 KO donor cells. Additional Foxp3 induction by peptide stimulation of immunodeficient recipients after transfer of CNS1 WT BDC2.5. tg or CNS1 KO BDC2.5 tg donor cells was not detectable.
Objective
Growing interest in measuring the cochlear duct length (CDL) has emerged, since it can influence the selection of cochlear implant electrodes. Currently the measurements are performed with ionized radiation imaging. Only a few studies have explored CDL measurements in magnetic resonance imaging (MRI). Therefore, the presented study aims to fill this gap by estimating CDL in MRI and comparing it with multislice computed tomography (CT).
Study Design
Retrospective data analyses of 42 cochleae.
Setting
Tertiary care medical center.
Methods
Diameter (A value) and width (B value) of the cochlea were measured in HOROS software. The CDL and the 2-turn length were determined by the elliptic circular approximation (ECA). In addition, the CDL, the 2-turn length, and the angular length were determined via HOROS software by the multiplanar reconstruction (MPR) method.
Results
CDL values were significantly shorter in MRI by MPR (d = 1.38 mm, P < .001) but not by ECA. Similar 2-turn length measurements were significantly lower in MRI by MPR (d = 1.67 mm) and ECA (d = 1.19 mm, both P < .001). In contrast, angular length was significantly higher in MRI (d = 26.79°, P < .001). When the values were set in relation to the frequencies of the cochlea, no clinically relevant differences were estimated (58 Hz at 28-mm CDL).
Conclusion
In the presented study, CDL was investigated in CT and MRI by using different approaches. Since no clinically relevant differences were found, diagnostics with radiation may be omitted prior to cochlear implantation; thus, a concept of radiation-free cochlear implantation could be established.
In an experiment with 114 children aged 9–12 years, we compared the ability to establish local and global coherence of narrative texts between auditory and audiovisual (auditory text and pictures) presentation. The participants listened to a series of short narrative texts, in each of which a protagonist pursued a goal. Following each text, we collected the response time to a query word that was either associated with a near or a distant causal antecedent of the final sentence. Analysis of these response times indicated that audiovisual presentation has advantages over auditory presentation for accessing information relevant for establishing both local and global coherence, but there are indications that this effect may be slightly more pronounced for global coherence.
Background
To identify injury patterns and mechanisms in professional men’s basketball by means of video match analysis.
Methods
In Germany, injuries are registered with the statutory accident insurance for professional athletes (VBG) by clubs or club physicians as part of occupational accident reporting. Moderate and severe injuries (absence of > 7 days) sustained during basketball competition in one of four seasons (2014–2017 and 2018–2019) in the first or second national men’s league in Germany were prospectively analyzed using a newly developed standardized observation form. Season 2017–2018 was excluded because of missing video material.
Results
Video analysis included 175 (53%) of 329 moderate and severe match injuries. Contact patterns categorized according to the different body sites yielded eight groups of typical injury patterns: one each for the head, shoulders, and ankles, two for the thighs, and three for the knees. Injuries to the head (92%), ankles (76%), shoulders (70%), knees (47%), and thighs (32%) were mainly caused by direct contact. The injury proportion of foul play was 19%. Most injuries (61%) occurred in the central zone below the basket. More injuries occurred during the second (OR 1.8, p = 0.018) and fourth quarter (OR 1.8, p = 0.022) than during the first and third quarter of the match.
Conclusion
The eight identified injury patterns differed substantially in their mechanisms. Moderate and severe match injuries to the head, shoulders, knees, and ankles were mainly caused by collision with opponents and teammates. Thus, stricter rule enforcement is unlikely to facilitate safer match play.
Background: Endovascular therapy is the gold standard in patients with hemodynamic relevant renal artery stenosis (RAS) resistant to medical therapy. The severity grading of the stenosis as well as the result assessment after endovascular approach is predominantly based on visible estimations of the anatomic appearance. We aim to investigate the application of color-coded DSA parameters to gain hemodynamic information during endovascular renal artery interventions and for the assessment of the procedures technical success.
Methods: We retrospectively evaluated 32 patients who underwent endovascular renal artery revascularization and applied color-coded summation imaging on selected monochromatic DSA images. The differences in time to peak (dTTP) of contrast enhancement in predefined anatomical measuring points were analyzed. Furthermore, differences in systolic blood pressure values (SBP) and serum creatinine were obtained. The value of underlying diabetes mellitus as a predictor for clinical outcome was assessed. Correlation analysis between the patients gender as well as the presence of diabetes mellitus and dTTP was performed.
Results: Endovascular revascularization resulted in statistically significant improvement in 4/7 regions of interest. Highly significant improvement of perfusion in terms of shortened TTP values could be found at the segmental artery level and in the intrastenotical segment (p<0.001), significant improvement prestenotical and in the apical renal parenchyma (p<0.05). In the other anatomic regions, differences revealed not to be significant. Differences between SBP and serum creatinine levels before and after the procedure were significant (p=0.004 and 0.0004). Patients ' gender as well as the presence of diabetes mellitus did not reveal to be predictors for the clinical success of the procedure. Furthermore, diabetes and gender did not show relevant correlation with dTTP in the parenchymal measuring points.
Conclusions: The supplementary use of color-coding DSA and the data gained from parametric images may provide helpful information in the evaluation of the procedures ' technical success. The segmental artery might be a particularly suitable vascular territory for analyzing differences in blood flow characteristics. Further studies with larger cohorts are needed to further confirm the diagnostic value of this technique.
Cartilage offers limited regenerative capacity. Cell-based approaches have emerged as a promising alternative in the treatment of cartilage defects and osteoarthritis. Due to their easy accessibility, abundancy, and chondrogenic potential mesenchymal stromal cells (MSCs) offer an attractive cell source. MSCs are often combined with natural or synthetic hydrogels providing tunable biocompatibility, biodegradability, and enhanced cell functionality. In this review, we focused on the different advantages and disadvantages of various natural, synthetic, and modified hydrogels. We examined the different combinations of MSC-subpopulations and hydrogels used for cartilage engineering in preclinical and clinical studies and reviewed the effects of added growth factors or gene transfer on chondrogenesis in MSC-laden hydrogels. The aim of this review is to add to the understanding of the disadvantages and advantages of various combinations of MSC-subpopulations, growth factors, gene transfers, and hydrogels in cartilage engineering.
Background
Mobile 3-dimensional fluoroscopes are an integral part of modern neurosurgical operating theatres and can also be used in combination with free available image post processing to depict cerebral vessels. In preparation of stereotactic surgery, preoperative Computed Tomography (CT) may be required for image fusion. Contrast CT may be of further advantage for image fusion as it regards the vessel anatomy in trajectory planning. Time-consuming in-hospital transports are necessary for this purpose. Mobile 3D-fluoroscopes may be used to generate a CT equal preoperative data set without an in-hospital transport. This study was performed to determine the feasibility and image quality of intraoperative 3-dimensional fluoroscopy with intravenous contrast administration in combination with stereotactical procedures.
Methods
6 patients were included in this feasibility study. After fixation in a radiolucent Mayfield clamp a rotational fluoroscopy scan was performed with 50 mL iodine contrast agent. The image data sets were merged with the existing MRI images at a planning station and visually evaluated by two observer. The operation times were compared between the frame-based and frameless systems (“skin-to-skin” and “OR entry to exit”).
Results
The procedure proves to be safe. The entire procedure from fluoroscope positioning to the transfer to the planning station took 5–6 min with an image acquisition time of 24 s. In 5 of 6 cases, the fused imaging was able to reproduce the vascular anatomy accurately and in good quality. Both time end-points were significantly shorter compared to frame-based interventions.
Conclusion
The images could easily be transferred to the planning and navigation system and were successfully merged with the MRI data set. The procedure can be completely integrated into the surgical workflow. Preoperative CT imaging or transport under anaesthesia may even be replaced by this technique in the future. Furthermore, hemorrhages can be successfully visualized intraoperatively and might prevent time delays in emergencies.
Despite successful recanalization of large-vessel occlusions in acute ischemic stroke, individual patients profit to a varying degree. Dynamic susceptibility-weighted perfusion and dynamic T1-weighted contrast-enhanced blood-brain barrier permeability imaging may help to determine secondary stroke injury and predict clinical outcome. We prospectively performed perfusion and permeability imaging in 38 patients within 24 h after successful mechanical thrombectomy of an occlusion of the middle cerebral artery M1 segment. Perfusion alterations were evaluated on cerebral blood flow maps, blood-brain barrier disruption (BBBD) visually and quantitatively on ktrans maps and hemorrhagic transformation on susceptibility-weighted images. Visual BBBD within the DWI lesion corresponded to a median ktrans elevation (IQR) of 0.77 (0.41–1.4) min−1 and was found in all 7 cases of hypoperfusion (100%), in 10 of 16 cases of hyperperfusion (63%), and in only three of 13 cases with unaffected perfusion (23%). BBBD was significantly associated with hemorrhagic transformation (p < 0.001). While BBBD alone was not a predictor of clinical outcome at 3 months (positive predictive value (PPV) = 0.8 [0.56–0.94]), hypoperfusion occurred more often in patients with unfavorable clinical outcome (PPV = 0.43 [0.10–0.82]) compared to hyperperfusion (PPV = 0.93 [0.68–1.0]) or unaffected perfusion (PPV = 1.0 [0.75–1.0]). We show that combined perfusion and permeability imaging reveals distinct infarct signatures after recanalization, indicating the severity of prior ischemic damage. It assists in predicting clinical outcome and may identify patients at risk of stroke progression.
Commuting to work: Nucleolar long non-coding RNA control ribosome biogenesis from near and far
(2021)
Gene expression is an essential process for cellular growth, proliferation, and differentiation. The transcription of protein-coding genes and non-coding loci depends on RNA polymerases. Interestingly, numerous loci encode long non-coding (lnc)RNA transcripts that are transcribed by RNA polymerase II (RNAPII) and fine-tune the RNA metabolism. The nucleolus is a prime example of how different lncRNA species concomitantly regulate gene expression by facilitating the production and processing of ribosomal (r)RNA for ribosome biogenesis. Here, we summarise the current findings on how RNAPII influences nucleolar structure and function. We describe how RNAPII-dependent lncRNA can both promote nucleolar integrity and inhibit ribosomal (r)RNA synthesis by modulating the availability of rRNA synthesis factors in trans. Surprisingly, some lncRNA transcripts can directly originate from nucleolar loci and function in cis. The nucleolar intergenic spacer (IGS), for example, encodes nucleolar transcripts that counteract spurious rRNA synthesis in unperturbed cells. In response to DNA damage, RNAPII-dependent lncRNA originates directly at broken ribosomal (r)DNA loci and is processed into small ncRNA, possibly to modulate DNA repair. Thus, lncRNA-mediated regulation of nucleolar biology occurs by several modes of action and is more direct than anticipated, pointing to an intimate crosstalk of RNA metabolic events.
Stress granules (SGs) are cytoplasmic condensates containing untranslated mRNP complexes. They are induced by various proteotoxic conditions such as heat, oxidative, and osmotic stress. SGs are believed to protect mRNPs from degradation and to enable cells to rapidly resume translation when stress conditions subside. SG dynamics are controlled by various posttranslationalmodifications, but the role of the ubiquitin system has remained controversial. Here, we present a comparative analysis addressing the involvement of the ubiquitin system in SG clearance. Using high-resolution immuno-fluorescence microscopy, we found that ubiquitin associated to varying extent with SGs induced by heat, arsenite, H2O2, sorbitol, or combined puromycin and Hsp70 inhibitor treatment. SG-associated ubiquitin species included K48- and K63-linked conjugates, whereas free ubiquitin was not significantly enriched. Inhibition of the ubiquitin activating enzyme, deubiquitylating enzymes, the 26S proteasome and p97/VCP impaired the clearance of arsenite- and heat-induced SGs, whereas SGs induced by other stress conditions were little affected. Our data underline the differential involvement of the ubiquitin system in SG clearance, a process important to prevent the formation of disease-linked aberrant SGs.
The aim of this study was to compare two different techniques of performing one-level spondylodesis for thoracolumbar burst fractures using either an autologous iliac crest bone graft (ICBG) or a porous tantalum fusion implant (PTFI). In a prospective nonrandomized study, 44 patients (20 women, 24 men; average age 43.1 +/- 13.2 years) suffering from severe thoracolumbar burst fractures were treated with combined anterior-posterior stabilization. An ICBG was used in 21 cases, and a PTFI was used in the other 23 cases. A two-year clinical and radiographic follow-up was carried out. There were no statistically significant differences in age, sex, localization/classification of the fracture, or visual analog scale (VAS) before injury between the two groups. All 44 patients were followed up for an average period of 533 days (range 173-1567). The sagittal spinal profile was restored by an average of 11.1 degrees (ICBG) vs. 14.3 degrees (PTFI) (monosegmental Cobb angle). Loss of correction until the last follow-up tended to be higher in the patients treated with ICBG than in those treated with PTFI (mean: 2.8 degrees vs. 1.6 degrees). Furthermore, significantly better restoration of the sagittal profile was obtained with the PTFI than with the iliac bone graft at the long-term follow-up (mean: ICBG 7.8 degrees, PTFI 12.3 degrees; p < 0.005). Short-segment posterior instrumentation combined with anterior one-level spondylodesis using either an ICBG or a PTFI resulted in sufficient correction of posttraumatic segmental kyphosis. PTFI might be a good alternative for autologous bone grafting and prevent donor site morbidities.
Comparing the appetitive learning performance of six European honeybee subspecies in a common apiary
(2021)
The Western honeybee (Apis mellifera L.) is one of the most widespread insects with numerous subspecies in its native range. How far adaptation to local habitats has affected the cognitive skills of the different subspecies is an intriguing question that we investigate in this study. Naturally mated queens of the following five subspecies from different parts of Europe were transferred to Southern Germany: A. m. iberiensis from Portugal, A. m. mellifera from Belgium, A. m. macedonica from Greece, A. m. ligustica from Italy, and A. m. ruttneri from Malta. We also included the local subspecies A. m. carnica in our study. New colonies were built up in a common apiary where the respective queens were introduced. Worker offspring from the different subspecies were compared in classical olfactory learning performance using the proboscis extension response. Prior to conditioning, we measured individual sucrose responsiveness to investigate whether possible differences in learning performances were due to differential responsiveness to the sugar water reward. Most subspecies did not differ in their appetitive learning performance. However, foragers of the Iberian honeybee, A. m. iberiensis, performed significantly more poorly, despite having a similar sucrose responsiveness. We discuss possible causes for the poor performance of the Iberian honeybees, which may have been shaped by adaptation to the local habitat.
Intercomparison of satellite-derived vegetation phenology is scarce in remote locations because of the limited coverage area and low temporal resolution of field observations. By their reliable near-ground observations and high-frequency data collection, PhenoCams can be a robust tool for intercomparison of land surface phenology derived from satellites. This study aims to investigate the transition dates of black spruce (Picea mariana (Mill.) B.S.P.) phenology by comparing fortnightly the MODIS normalized difference vegetation index (NDVI) and the enhanced vegetation index (EVI) extracted using the Google Earth Engine (GEE) platform with the daily PhenoCam-based green chromatic coordinate (GCC) index. Data were collected from 2016 to 2019 by PhenoCams installed in six mature stands along a latitudinal gradient of the boreal forests of Quebec, Canada. All time series were fitted by double-logistic functions, and the estimated parameters were compared between NDVI, EVI, and GCC. The onset of GCC occurred in the second week of May, whereas the ending of GCC occurred in the last week of September. We demonstrated that GCC was more correlated with EVI (R\(^2\) from 0.66 to 0.85) than NDVI (R\(^2\) from 0.52 to 0.68). In addition, the onset and ending of phenology were shown to differ by 3.5 and 5.4 days between EVI and GCC, respectively. Larger differences were detected between NDVI and GCC, 17.05 and 26.89 days for the onset and ending, respectively. EVI showed better estimations of the phenological dates than NDVI. This better performance is explained by the higher spectral sensitivity of EVI for multiple canopy leaf layers due to the presence of an additional blue band and an optimized soil factor value. Our study demonstrates that the phenological observations derived from PhenoCam are comparable with the EVI index. We conclude that EVI is more suitable than NDVI to assess phenology in evergreen species of the northern boreal region, where PhenoCam data are not available. The EVI index could be used as a reliable proxy of GCC for monitoring evergreen species phenology in areas with reduced access, or where repeated data collection from remote areas are logistically difficult due to the extreme weather.
Cytomegalovirus (CMV) infection is a major cause of morbidity and mortality following hematopoietic stem cell transplantation (HSCT). Measuring CMV-specific cellular immunity may improve the risk stratification and management of patients. IFN-γ ELISpot assays, based on the stimulation of peripheral blood mononuclear cells with CMV pp65 and IE-1 proteins or peptides, have been validated in clinical settings. However, it remains unclear to which extend the T-cell response to synthetic peptides reflect that mediated by full-length proteins processed by antigen-presenting cells. We compared the stimulating ability of pp65 and IE-1 proteins and corresponding overlapping peptides in 16 HSCT recipients using a standardized IFN-γ ELISpot assay. Paired qualitative test results showed an overall 74.4% concordance. Discordant results were mainly due to low-response tests, with one exception. One patient with early CMV reactivation and graft-versus-host disease, sustained CMV DNAemia and high CD8\(^+\) counts showed successive negative protein-based ELISpot results but a high and sustained response to IE-1 peptides. Our results suggest that the response to exogenous proteins, which involves their uptake and processing by antigen-presenting cells, more closely reflects the physiological response to CMV infection, while the response to exogenous peptides may lead to artificial in vitro T-cell responses, especially in strongly immunosuppressed patients.
Background
To implement a tangential treatment technique for whole breast irradiation using the Varian Halcyon and to compare it with Elekta Synergy Agility plans.
Methods
For 20 patients two comparable treatment plans with respect to dose coverage and normal tissue sparing were generated. Tangential field-in-field treatment plans (Pinnacle/Synergy) were replanned using the sliding window technique (Eclipse/Halcyon). Plan specific QA was performed using the portal Dosimetry and the ArcCHECK phantom. Imaging and treatment dose were evaluated for treatment delivery on both systems using a modified CIRS Phantom.
Results
The mean number of monitor units for a fraction dose of 2.67 Gy was 515 MUs and 260 MUs for Halcyon and Synergy Agility plans, respectively. The homogeneity index and dose coverage were similar for both treatment units. The plan specific QA showed good agreement between measured and calculated plans. All Halcyon plans passed portal dosimetry QA (3%/2 mm) with 100% points passing and ArcCheck QA (3%/2 mm) with 99.5%. Measurement of the cumulated treatment and imaging dose with the CIRS phantom resulted in lower dose to the contralateral breast for the Halcyon plans.
Conclusions
For the Varian Halcyon a plan quality similar to the Elekta Synergy device was achieved. For the Halcyon plans the dose contribution from the treatment fields to the contralateral breast was even lower due to less interleaf transmission of the Halcyon MLC and a lower contribution of scattered dose from the collimator system.
Purpose
To compare radiotherapy plans between an O-ring and a conventional C-arm linac for hypofractionated high-dose prostate radiotherapy in terms of plan quality, dose distribution, and quality assurance in a multi-vendor environment.
Methods
Twenty prostate cancer treatment plans were irradiated on the O-ring Varian Halcyon linac and were re-optimized for the C-arm Elekta Synergy Agility linac. Dose-volume histogram metrics for target coverage and organ at risk dose, quality assurance, and monitor units were retrospectively compared. Patient-specific quality assurance with ion chamber measurements, gamma index analysis, and portal dosimetry was performed using the Varian Portal Dosimetry system and the ArcCHECK® phantom (Sun Nuclear Corporation). Prostate-only radiotherapy was delivered with simultaneous integrated boost (SIB) volumetric modulated arc therapy (VMAT) in 20 fractions of 2.5/3.0 Gy each.
Results
For both linacs, target coverage was excellent and plan quality comparable. Homogeneity in PTVBoost was high for Synergy as well as Halcyon with a mean homogeneity index of 0.07 ± 0.01 and 0.05 ± 0.01, respectively. Mean dose for the organs at risk rectum and bladder differed not significantly between the linacs but were higher for the femoral heads and penile bulb for Halcyon. Quality assurance showed no significant differences in terms of ArcCHECK gamma pass rates. Median pass rate for 3%/2 mm was 99.3% (96.7 to 99.8%) for Synergy and 99.8% (95.6 to 100%) for Halcyon. Agreement between calculated and measured dose was high with a median deviation of −0.6% (−1.7 to 0.8%) for Synergy and 0.2% (−0.6 to 2.3%) for Halcyon. Monitor units were higher for the Halcyon by approximately 20% (p < 0.001).
Conclusion
Hypofractionated high-dose prostate cancer SIB VMAT on the Halcyon system is feasible with comparable plan quality in reference to a standard C-arm Elekta Synergy linac.
Candida auris is an emerging pathogen with resistance to many commonly used antifungal agents. Infections with C. auris require rapid and reliable detection methods to initiate successful medical treatment and contain hospital outbreaks. Conventional identification methods are prone to errors and can lead to misidentifications. PCR-based assays, in turn, can provide reliable results with low turnaround times. However, only limited data are available on the performance of commercially available assays for C. auris detection. In the present study, the two commercially available PCR assays AurisID (OLM, Newcastle Upon Tyne, UK) and Fungiplex Candida Auris RUO Real-Time PCR (Bruker, Bremen, Germany) were challenged with 29 C. auris isolates from all five clades and eight other Candida species as controls. AurisID reliably detected C. auris with a limit of detection (LoD) of 1 genome copies/reaction. However, false positive results were obtained with high DNA amounts of the closely related species C. haemulonii, C. duobushaemulonii and C. pseudohaemulonii. The Fungiplex Candida Auris RUO Real-Time PCR kit detected C. auris with an LoD of 9 copies/reaction. No false positive results were obtained with this assay. In addition, C. auris could also be detected in human blood samples spiked with pure fungal cultures by both kits. In summary, both kits could detect C. auris-DNA at low DNA concentrations but differed slightly in their limits of detection and specificity.
Complementation of a bimolecular Antibody-Derivative within the context of the Immunological Synapse
(2021)
Cancer is a disease of uncontrolled cell proliferation and migration. Downregulation of antigen-presenting major histocompatibility complex (MHC) and co-stimulatory molecules are two of the most commonly used pathways by cancer cells to escape from immune surveillance. Therefore, many approaches have been developed for restoring the immune surveillance in cancer patients. One approach is to redirect the patient’s own T cells for tumor cell destruction. For T cell function it is important to induce a durable and robust cytotoxic response against target cells and to generate memory T cells, after MHC-mediated recognition of foreign intracellular antigens presented on the surface of antigen presenting cells (APC). Because of these cytotoxic properties, T cell mediated immunotherapy has been established as an effective and durable anti-neoplastic treatment. Different T cell mediated therapies for cancer treatment exist. One of them is using bispecific antibody fragments, so called bi-sepcific T cell engagers (BiTEs), for retargeting of T cells against single antigen positive tumor cells. The BiTE antibodies have two antigen binding domains, one against a target on the target cell, the second against CD3 on the T cells, facilitating cell-to-cell interactions. However, suitable single tumor antigens are limited, which restricts this approach to very few tumor types. To overcome this limitation, we have developed T cell-engaging antibody derivatives, termed hemibodies. Hemibodies exist as two complementary polypeptide chains. Each consists of two specific domains. On one end there is a single-chain variable fragment (scFv) against a target protein and on the other end there is either the heavy chain variable domain (VH) or light chain variable domain (VL) of an anti-CD3 binding antibody. Only when both hemibodies bind their respective antigens on the same tumor cell, the complementary anti CD3 VH and VL domains become aligned and reconstitute the functional CD3 binding-domain to engage T cells.
For targeting malignant cells of hematopoietic origin, we used hemibodies against CD45 and HLA-A2. They were expressed in CHO cells, then purified via Strep-tag. To get more insight into the hemibody mechanism of T cell mediated target cell killing, we analyzed the biochemical and functional properties of hemibodies in more detail.
Our main finding indicates that VLαCD3-scFvαHLA-A2 and VHαCD3-scFvαCD45 hemibodies induce an atypical immunological synapse characterized by a co-localization of HLA-A2 and CD45 out of the target cell -T cell interface. Nevertheless, hemibodies induce a high caspase activity in target cells in a concentration-dependent manner at nanomolar concentrations in vitro. Looking at ZAP70, which is usually recruited from the cytoplasm to the CD3 receptor in the middle of the cell-cell interface, we were able to detect activated ZAP70 outside of the cell-cell interface in the presence of hemibodies. In contrast cells treated with BiTEs show a central recruitment in the cell-cell interface as expected.
We looked also at the interaction of hemibodies with soluble recombinant CD3 epsilon/gamma protein in the absence of target cells. The binding could be measured only at very high concentration out of the therapeutic window.
This work contributes to the mechanistic understanding, which underlies the hemibody technology as a new dual antigen restricted T cell-mediated immunotherapy of cancer.
We compute genus-0 Belyi maps with prescribed monodromy and strictly verify the computed results. Among the computed examples are almost simple primitive groups that satisfy the rational rigidity criterion yielding polynomials with prescribed Galois groups over Q(t). We also give an explicit version of a theorem of Magaard, which lists all sporadic groups occurring as composition factors of monodromy groups of rational functions.
To enable a sustainable supply of chemicals, novel biotechnological solutions are required that replace the reliance on fossil resources. One potential solution is to utilize tailored biosynthetic modules for the metabolic conversion of CO2 or organic waste to chemicals and fuel by microorganisms. Currently, it is challenging to commercialize biotechnological processes for renewable chemical biomanufacturing because of a lack of highly active and specific biocatalysts. As experimental methods to engineer biocatalysts are time- and cost-intensive, it is important to establish efficient and reliable computational tools that can speed up the identification or optimization of selective, highly active, and stable enzyme variants for utilization in the biotechnological industry. Here, we review and suggest combinations of effective state-of-the-art software and online tools available for computational enzyme engineering pipelines to optimize metabolic pathways for the biosynthesis of renewable chemicals. Using examples relevant for biotechnology, we explain the underlying principles of enzyme engineering and design and illuminate future directions for automated optimization of biocatalysts for the assembly of synthetic metabolic pathways.
Ziel der Untersuchung:
Verglichen wurden die räumlichen Abweichungen der Bohrpfade nach virtueller Planung von Schablonen geführten Trepanationen mit Hilfe der Softwaresysteme SicatEndo (SE) und coDiagnostiX (CDX) und der benötigte Arbeitsaufwand.
Material und Methode:
Basierend auf µCT-Datensätzen von humanen obliterierten Frontzähnen wurden identische Kunststoffzähne und acht Zahnmodelle (4 Ober-, 4 Unterkiefer) hergestellt. Es wurde jeweils ein DVT und ein Oberflächenscan angefertigt. Diese Datensätze (DICOM; STL) wurden in die Softwaresysteme importiert und fusioniert. Anschließend wurden die Bohrpfade für je 16 Probenzähne pro Software geplant. Mit Hilfe der erstellten Schablonen wurden alle Trepanationen an den im Phantomkopf fixierten Modellen von einem Behandler durchgeführt. Nach Erschließung des apikalen Wurzelkanalanteils wurde ein DVT angefertigt und mit dem präoperativen DVT überlagert. Die räumliche drei-dimensionale (3D) Abweichung zwischen virtuell geplantem und tatsächlichem Bohrpfad wurde über die Vektorlänge bestimmt und der Arbeitsaufwand anhand der Planungszeit und der Anzahl der Mausklicks pro Kiefer erfasst.
Ergebnisse:
Für die Trepanationen mit SE zeigten sich signifikant geringe Abweichungen an der Bohrerspitze vestibulär-oral [CDX 0,54mm ± 0,32mm; SE 0,12mm ± 0,11mm; p < 0.05], 3D [CDX 0,74mm ± 0,26 mm; SE 0,35mm ± 0,17mm; p < 0.05] und hinsichtlich des Winkels [CDX 1,57° ± 0,76°; SE 0,68° ± 0,41°; p < 0.05] als mit CDX. Für CDX war der Planungsaufwand signifikant geringer als für SE hinsichtlich Planungszeit [CDX Ø 10min 50sec; SE Ø 20min 28sec] und hinsichtlich der Anzahl der Klicks pro Kiefer [CDX Ø 107; SE Ø 341].
Zusammenfassung:
Beide Planungssysteme ermöglichen ausreichend präzise Schablonen geführte Bohrungen zur Erschließung apikaler Wurzelkanalanteile.
Background
Evaluation of delivered dose to the dominant intraprostatic lesion (DIL) for moderately hypofractionated radiotherapy of prostate cancer by cone beam computed tomography (CBCT)-based dose accumulation and target coverage analysis.
Methods
Twenty-three patients with localized prostate cancer treated with moderately hypofractionated prostate radiotherapy with simultaneous integrated boost (SIB) between December 2016 and February 2020 were retrospectively analyzed. Included patients were required to have an identifiable DIL on bi-parametric planning magnetic resonance imaging (MRI). After import into the RayStation treatment planning system and application of a step-wise density override, the fractional doses were computed on each CBCT and were consecutively mapped onto the planning CT via a deformation vector field derived from deformable image registration. Fractional doses were accumulated for all CBCTs and interpolated for missing CBCTs, resulting in the delivered dose for PTV\(_{DIL}\), PTV\(_{Boost}\), PTV, and the organs at risk. The location of the index lesions was recorded according to the sector map of the Prostate Imaging Reporting and Data System (PIRADS) Version 2.1. Target coverage of the index lesions was evaluated and stratified for location.
Results
In total, 338 CBCTs were available for analysis. Dose accumulation target coverage of PTV\(_{DIL}\), PTV\(_{Boost}\), and PTV was excellent and no cases of underdosage in D\(_{Mean}\), D_95%, D_02%, and D_98% could be detected. Delivered rectum D\(_{Mean}\) did not significantly differ from the planned dose. Bladder mean DMean was higher than planned with 19.4 ± 7.4 Gy versus 18.8 ± 7.5 Gy, p < 0.001. The penile bulb showed a decreased delivered mean DMean with 29.1 ± 14.0 Gy versus 29.8 ± 14.4 Gy, p < 0.001. Dorsal DILs, defined as DILs in the posterior medial peripheral zone of the prostate, showed a significantly lower delivered dose with a mean DMean difference of 2.2 Gy (95% CI 1.3–3.1 Gy, p < 0.001) compared to ventral lesions.
Conclusions
CBCT-based dose accumulation showed an adequate delivered dose to the dominant intraprostatic lesion and organs at risk within planning limits. Cautious evaluation of the target coverage for index lesions adjacent to the rectum is warranted to avoid underdosage.
Hepatitis B virus is a major human pathogen, which forms enveloped virus particles. During viral maturation, membrane-bound hepatitis B surface proteins package hepatitis B core protein capsids. This process is intercepted by certain peptides with an “LLGRMKG” motif that binds to the capsids at the tips of dimeric spikes. With microcalorimetry, electron cryo microscopy and peptide microarray-based screens, we have characterized the structural and thermodynamic properties of peptide binding to hepatitis B core protein capsids with different secretion phenotypes. The peptide “GSLLGRMKGA” binds weakly to hepatitis B core protein capsids and mutant capsids with a premature (F97L) or low-secretion phenotype (L60V and P5T). With electron cryo microscopy, we provide novel structures for L60V and P5T and demonstrate that binding occurs at the tips of the spikes at the dimer interface, splaying the helices apart independent of the secretion phenotype. Peptide array screening identifies “SLLGRM” as the core binding motif. This shortened motif binds only to one of the two spikes in the asymmetric unit of the capsid and induces a much smaller conformational change. Altogether, these comprehensive studies suggest that the tips of the spikes act as an autonomous binding platform that is unaffected by mutations that affect secretion phenotypes.
A series of methylene-bridged bis(triarylboranes) has been synthesized via two complementary routes using metal-free catalytic Si/B exchange condensation under mild conditions. The title compounds comprise two borane moieties that show effective internal π-conjugation involving the respective boron centers and the adjacent hetaryl groups. Conjugation between both borane units, however, is disrupted by the aliphatic linker. Cyclic voltammetry revealed minimal electronic communication between the boron centers, as evidenced by two closely spaced reduction processes. The UV-vis spectra showed bathochromic shifted absorption bands compared to related monoboranes, which is attributed to the methylene bridge. A further red-shift results upon introduction of methyl or SiMe\(_3\) groups at the terminal thiophene rings.
In recent years <mi>PI</mi>-conjugated organoboron polymers and BN-doped polycyclic aromatic hydrocarbons have attracted a lot of interest due to their great potential in organic electronics. However, there are only few known examples of conjugated polymers with BN units in their main chain. Within this work silazane cleavage with silicon-boron (Si/B) exchange for the synthesis of a novel class of inorganic-organic hybrid polymers is demonstrated. These polymers consist of alternating NBN and para-phenylene units in the main chain. Photophysical studies and TD-DFT calculations for the polymer and molecular model systems were carried out, revealing a low extent of <mi>PI</mi>-conjugation across the NBN units. The new polymers can be used as macromolecular polyligands by a cross-linking reaction with a ZrIV compound. In the next chapter the synthesis and characterization of the first poly(p-phenylene iminoborane) is presented. This novel inorganic–organic hybrid polymer can be described as a BN analogue of the well-known poly(p-phenylene vinylene) (PPV) and is also accessible using the previously described Si/B exchange as synthetic strategy. Photophysical investigations and TD-DFT calculations on the polymer and corresponding model oligomers provide clear evidence for <mi>PI</mi>-conjugation across the B=N units and extension of the conjugation path with increasing chain length. Furthermore, a possible application of Si/B exchange for the synthesis of polysulfoximines was explored. Herein, diaryl sulfoximines and a p-phenylene bisborane serve as building blocks for new BN- and BO-doped alternating inorganic–organic hybrid copolymers. While the BN-linked polymers were accessible by a facile silicon/boron exchange protocol, the synthesis of polymers with B–O linkages in the main chain is achieved by salt elimination. In the last chapter the concept of Si/B exchange was investigated for the synthesis of BP-linked oligomers. Herein oligomers with sterically less demanding substituents (substituents: 2,4,6-trimethylphenyl or 2,4,6-tri-iso-propylphenyl) at the phosphorus are accessible using Si/B exchange, but the oligomer with Mes* (2,4,6-tri-tert-butylphenyl) as substituent needed a salt elimination pathway to give the desired product. Experimental data and theoretical investigations indicate, that the P-substituent has a high influence on the geometry of the phosphorus center and therefore on the possible conjugation over the BP units.
Adrenal Cushing’s Syndrome (CS) is a rare but life-threatening disease and therefore it is of great importance to understand the pathogenesis leading to adrenal CS. It is well accepted that Protein Kinase A (PKA) signalling mediates steroid secretion in adrenocortical cells. PKA is an inactive heterotetramer, consisting of two catalytic and two regulatory subunits. Upon cAMP binding to the regulatory subunits, the catalytic subunits are released and are able to phosphorylate their target proteins. Recently, activating somatic mutations affecting the catalytic subunit a of PKA have been identified in a sub-population of cortisol-producing adenomas (CPAs) associated with overt CS. Interestingly, the PKA regulatory subunit IIb has long been known to have significantly lower protein levels in a sub-group of CPAs compared to other adrenocortical tumours. Yet, it is unknown, why these CPAs lack the regulatory subunit IIb, neither are any functional consequences nor are the underlying regulation mechanisms leading to reduced RIIb levels known. The results obtained in this thesis show a clear connection between Ca mutations and reduced RIIb protein levels in CPAs but not in other adrenocortical tumours. Furthermore, a specific pattern of PKA subunit expression in the different zones of the normal adrenal gland is demonstrated. In addition, a Ca L206R mutation-mediated degradation of RIIb was observed in adrenocortical cells in vitro. RIIb degradation was found to be mediated by caspases and by performing mutagenesis experiments of the regulatory subunits IIb and Ia, S114 phosphorylation of RIIb was identified to make RIIb susceptible for degradation. LC-MS/MS revealed RIIb interaction partners to differ in the presence of either Ca WT and Ca L206R. These newly identified interaction partners are possibly involved in targeting RIIb to subcellular compartments or bringing it into spatial proximity of degrading enzymes. Furthermore, reducing RIIb protein levels in an in vitro system were shown to correlate with increased cortisol secretion also in the absence of PRKACA mutations. The inhibiting role of RIIb in cortisol secretion demonstrates a new function of this regulatory PKA subunit, improving the understanding of the complex regulation of PKA as key regulator in many cells.
Constraining graph layouts - that is, restricting the placement of vertices and the routing of edges to obey certain constraints - is common practice in graph drawing.
In this book, we discuss algorithmic results on two different restriction types:
placing vertices on the outer face and on the integer grid.
For the first type, we look into the outer k-planar and outer k-quasi-planar graphs, as well as giving a linear-time algorithm to recognize full and closed outer k-planar graphs Monadic Second-order Logic.
For the second type, we consider the problem of transferring a given planar drawing onto the integer grid while perserving the original drawings topology;
we also generalize a variant of Cauchy's rigidity theorem for orthogonal polyhedra of genus 0 to those of arbitrary genus.
Contribution of adventitia-derived stem and progenitor cells to new vessel formation in tumors
(2021)
Blocking tumor vascularization has not yet come to fruition to the extent it was hoped for, as angiogenesis inhibitors have shown only partial success in the clinic. We hypothesized that under- appreciated vascular wall-resident stem and progenitor cells (VW-SPCs) might be involved in tumor vascularization and influence effectiveness of anti-angiogenic therapy. Indeed, in patient samples, we observed that vascular adventitia-resident CD34\(^+\) VW-SPCs are recruited to tumors in situ from co-opted vessels. To elucidate this in detail, we established an ex vivo model using concomitant embedding of multi-cellular tumor spheroids (MCTS) and mouse aortic rings (ARs) into collagen
gels, similar to the so-called aortic ring assay (ARA). Moreover, ARA was modified by removing the ARs’ adventitia that harbors VW-SPCs. Thus, this model enabled distinguishing the contribution of VW-SPCs from that of mature endothelial cells (ECs) to new vessel formation. Our results show that the formation of capillary-like sprouts is considerably delayed, and their number and network formation were significantly reduced by removing the adventitia. Substituting iPSC-derived neural spheroids for MCTS resulted in distinct sprouting patterns that were also strongly influenced by the
presence or absence of VW-SPCs, also underlying the involvement of these cells in non-pathological vascularization. Our data suggest that more comprehensive approaches are needed in order to block all of the mechanisms contributing to tumor vascularization.
Since the addition of fluoride to drinking water in the 1940s, there have been frequent and sometimes heated discussions regarding its benefits and risks. In a recently published review, we addressed the question if current exposure levels in Europe represent a risk to human health. This review was discussed in an editorial asking why we did not calculate benchmark doses (BMD) of fluoride neurotoxicity for humans. Here, we address the question, why it is problematic to calculate BMDs based on the currently available data. Briefly, the conclusions of the available studies are not homogeneous, reporting negative as well as positive results; moreover, the positive studies lack control of confounding factors such as the influence of well-known neurotoxicants. We also discuss the limitations of several further epidemiological studies that did not meet the inclusion criteria of our review. Finally, it is important to not only focus on epidemiological studies. Rather, risk analysis should consider all available data, including epidemiological, animal, as well as in vitro studies. Despite remaining uncertainties, the totality of evidence does not support the notion that fluoride should be considered a human developmental neurotoxicant at current exposure levels in European countries.
A number of novel alkynyl-functionalized diarylbis(dimethylamino)diboranes(4) are prepared by salt metathesis, and the appended alkynyl groups are subjected to hydroboration. Their reactions with monohydroboranes lead to discrete boryl-appended diborane(4) species, while dihydroboranes induce their catenation to oligomeric species, the first known examples of well-characterized macromolecular species with B−B bonds. The oligomeric species were found to comprise up to ten repeat units and are soluble in common organic solvents. Some of the oligomeric species have good air stability and all were characterized by NMR and vibrational spectroscopy and size-exclusion chromatography techniques.
Melt electrowriting (MEW) is a high-resolution additive manufacturing technology that balances multiple parametric variables to arrive at a stable fabrication process. The better understanding of this balance is underscored here using high-resolution camera vision of jet stability profiles in different electrical fields. Complementing this visual information are fiber-diameter measurements obtained at precise points, allowing the correlation to electrified jet properties. Two process signatures—the jet angle and for the first time, the Taylor cone area—are monitored and analyzed with a machine vision system, while SEM imaging for diameter measurement correlates real-time information. This information, in turn, allows the detection and correction of fiber pulsing for accurate jet placement on the collector, and the in-process assessment of the fiber diameter. Improved process control is used to successfully fabricate collapsible MEW tubes; structures that require exceptional accuracy and printing stability. Using a precise winding angle of 60° and 300 layers, the resulting 12 mm-thick tubular structures have elastic snap-through instabilities associated with mechanical metamaterials. This study provides a detailed analysis of the fiber pulsing occurrence in MEW and highlights the importance of real-time monitoring of the Taylor cone volume to better understand, control, and predict printing instabilities.
T cell anergy is a common mechanism of T cell tolerance. However, although anergic T cells are retained for longer time periods in their hosts, they remain functionally passive. Here, we describe the induction of anergic CD4\(^+\) T cells in vivo by intravenous application of high doses of antigen and their subsequent conversion into suppressive Foxp3\(^-\) IL-10\(^+\) Tr1 cells but not Foxp3\(^+\) Tregs. We describe the kinetics of up-regulation of several memory-, anergy- and suppression-related markers such as CD44, CD73, FR4, CD25, CD28, PD-1, Egr-2, Foxp3 and CTLA-4 in this process. The conversion into suppressive Tr1 cells correlates with the transient intracellular CTLA-4 expression and required the restimulation of anergic cells in a short-term time window. Restimulation after longer time periods, when CTLA-4 is down-regulated again retains the anergic state but does not lead to the induction of suppressor function. Our data require further functional investigations but at this stage may suggest a role for anergic T cells as a circulating pool of passive cells that may be re-activated into Tr1 cells upon short-term restimulation with high and systemic doses of antigen. It is tentative to speculate that such a scenario may represent cases of allergen responses in non-allergic individuals.
Corfu is a framework for satellite software, not only for the onboard part but also for the ground. Developing software with Corfu follows an iterative model-driven approach. The basis of the process is an engineering model. Engineers formally describe the basic structure of the onboard software in configuration files, which build the engineering model. In the first step, Corfu verifies the model at different levels. Not only syntactically and semantically but also on a higher level such as the scheduling.
Based on the model, Corfu generates a software scaffold, which follows an application-centric approach. Software images onboard consist of a list of applications connected through communication channels called topics. Corfu’s generic and generated code covers this fundamental communication, telecommand, and telemetry handling. All users have to do is inheriting from a generated class and implement the behavior in overridden methods. For each application, the generator creates an abstract class with pure virtual methods. Those methods are callback functions, e.g., for handling telecommands or executing code in threads.
However, from the model, one can not foresee the software implementation by users. Therefore, as an innovation compared to other frameworks, Corfu introduces feedback from the user code back to the model. In this way, we extend the engineering model with information about functions/methods, their invocations, their stack usage, and information about events and telemetry emission. Indeed, it would be possible to add further information extraction for additional use cases. We extract the information in two ways: assembly and source code analysis. The assembly analysis collects information about the stack usage of functions and methods.
On the one side, Corfu uses the gathered information to accomplished additional verification steps, e.g., checking if stack usages exceed stack sizes of threads. On the other side, we use the gathered information to improve the performance of onboard software. In a use case, we show how the compiled binary and bandwidth towards the ground is reducible by exploiting source code information at run-time.
We examined 143 patients suffering from FMS, a syndrome characterized by chronic widespread pain, sleep disturbances, and fatigue. Etiology and pathophysiology of FMS are scarcely understood. In recent years abnormalities of small Aδ- and C-nerve fibers have been found in subgroups of FMS patients. It is yet unclear how such SFP is caused in FMS patients and how it contributes to FMS symptoms.
We used CCM to analyze corneal small nerve fibers and associated LC, comparing FMS patients’ results to those from 65 healthy controls and 41 disease controls suffering from SFN. We, further, assessed expression levels of mRNA and miRNA in keratinocytes taken from skin punch biopsies of FMS patients and healthy controls kept as monocellular cell cultures. A screening was performed using NGS in a small cohort of 12 FMS patients and 5 healthy controls. Results were validated in larger cohorts by qRT-PCR.
As in previous studies IENFD and CNFD were reduced in a subgroup of FMS patients. We found identical LC densities in FMS patients, healthy controls, and SFN patients. The subpopulation of dLCfiber contact in FMS and SFN patients was lower than in healthy controls. Our RNA expression analysis revealed one mRNA that was expressed higher in FMS patients than in controls: PRSS21.
We conclude that reduced neurotrophic signaling of LC may contribute to SFP in the cornea. Epidermal PRSS21 expression and dLCfiber contact density are promising biomarker candidates for FMS diagnosis.
Physical and mental well-being during the COVID-19 pandemic is typically assessed via surveys, which might make it difficult to conduct longitudinal studies and might lead to data suffering from recall bias. Ecological momentary assessment (EMA) driven smartphone apps can help alleviate such issues, allowing for in situ recordings. Implementing such an app is not trivial, necessitates strict regulatory and legal requirements, and requires short development cycles to appropriately react to abrupt changes in the pandemic. Based on an existing app framework, we developed Corona Health, an app that serves as a platform for deploying questionnaire-based studies in combination with recordings of mobile sensors. In this paper, we present the technical details of Corona Health and provide first insights into the collected data. Through collaborative efforts from experts from public health, medicine, psychology, and computer science, we released Corona Health publicly on Google Play and the Apple App Store (in July 2020) in eight languages and attracted 7290 installations so far. Currently, five studies related to physical and mental well-being are deployed and 17,241 questionnaires have been filled out. Corona Health proves to be a viable tool for conducting research related to the COVID-19 pandemic and can serve as a blueprint for future EMA-based studies. The data we collected will substantially improve our knowledge on mental and physical health states, traits and trajectories as well as its risk and protective factors over the course of the COVID-19 pandemic and its diverse prevention measures.
Objective: Substantia nigra hyperechogenicity is found in children with attention- deficit hyperactivity disorder (ADHD). Research with transcranial sonography (TCS) in adults suggests that echogenic alterations are linked to subclinical behavioral deficits and that brain iron homeostasis is involved in the signal genesis. The purpose of this study was to explore substantia nigra echogenicity in healthy children, to assess age-related changes and to investigate whether echogenic signals relate to subclinical alterations in behavior. Furthermore, associations of central nigral neuromelanin measures and peripheral serum iron parameters to echogenic signals of the substantia nigra were evaluated. Methods: In a multimodal study design, neuroimaging of the substantia nigra was conducted with TCS and neuromelanin-sensitive magnetic resonance imaging (MRI) in 28 healthy children (8 − 12 years). Correlations and multiple regression analyses determined associations between the neuroimaging methods, behavioral data from Strength and Difficulties Questionnaire (SDQ) and serum iron-related parameters. Results: Substantia nigra echogenicity correlated inversely with hyperactivity ratings in healthy, non-ADHD children (r = −.602, p = .001). Echogenic sizes did not change as a function of age. Neuromelanin-sensitive MRI measures of the substantia nigra and peripheral serum iron parameters were not associated with nigral TCS signals. Conclusion: In healthy children behavioral differences in hyperactive tendencies are associated with differences in substantia nigra echogenicity. This could help to identify those children who are at risk of subclinical ADHD.
Background: Neurologic symptom severity and deterioration at 24 hours (h) predict long-term outcomes in patients with acute large vessel occlusion (LVO) stroke of the anterior circulation. We aimed to examine the association of baseline multiparametric CT imaging and clinical factors with the course of neurologic symptom severity in the first 24 h after endovascular treatment (EVT). Methods: Patients with LVO stroke of the anterior circulation were selected from a prospectively acquired consecutive cohort of patients who underwent multiparametric CT, including non-contrast CT, CT angiography and CT perfusion before EVT. The symptom severity was assessed on admission and after 24 h using the 42-point National Institutes of Health Stroke Scale (NIHSS). Clinical and imaging data were compared between patients with and without early neurological deterioration (END). END was defined as an increase in ≥4 points, and a significant clinical improvement as a decrease in ≥4 points, compared to NIHSS on admission. Multivariate regression analyses were used to determine independent associations of imaging and clinical parameters with NIHSS score increase or decrease in the first 24 h. Results: A total of 211 patients were included, of whom 38 (18.0%) had an END. END was significantly associated with occlusion of the internal carotid artery (odds ratio (OR), 4.25; 95% CI, 1.90–9.47) and the carotid T (OR, 6.34; 95% CI, 2.56–15.71), clot burden score (OR, 0.79; 95% CI, 0.68–0.92) and total ischemic volume (OR, 1.01; 95% CI, 1.00–1.01). In a comprehensive multivariate analysis model including periprocedural parameters and complications after EVT, carotid T occlusion remained independently associated with END, next to reperfusion status and intracranial hemorrhage. Favorable reperfusion status and small ischemic core volume were associated with clinical improvement after 24 h. Conclusions: The use of imaging parameters as a surrogate for early NIHSS progression in an acute LVO stroke after EVT reached limited performance with only carotid T occlusion as an independent predictor of END. Reperfusion status and early complications in terms of intracranial hemorrhage are critical factors that influence patient outcome in the acute stroke phase after EVT.
The safety of future spaceflight depends on space surveillance and space traffic management, as the density of objects in Earth orbit has reached a level that requires collision avoidance maneuvers to be performed on a regular basis to avoid a mission or, in the context of human space flight, life-endangering threat. Driven by enhanced sensor systems capable of detecting centimeter-sized debris, megaconstellations and satellite miniaturization, the space debris problem has revealed many parallels to the plastic waste in our oceans, however with much less visibility to the eye. Future catalog sizes are expected to increase drastically, making it even more important to detect potentially dangerous encounters as early as possible.
Due to the limited number of monitoring sensors, continuous observation of all objects is impossible, resulting in the need to predict the orbital paths and their uncertainty via models to perform collision risk assessment and space object catalog maintenance. For many years the uncertainty models used for orbit determination neglected any uncertainty in the astrodynamic force models, thereby implicitly assuming them to be flawless descriptions of the true space environment. This assumption is known to result in overly optimistic uncertainty estimates, which in turn complicate collision risk analysis.
The keynote of this doctoral thesis is to establish uncertainty realism for low Earth orbiting satellites via a physically connected quantification of the dominant force model uncertainties, particularly multiple sources of atmospheric density uncertainty and orbital gravity uncertainty.
The resulting process noise models are subsequently integrated into classical and state of the art orbit determination algorithms. Their positive impact is demonstrated via numerical orbit determination simulations and a collision risk assessment study using all non-restricted objects in the official United States space catalogs. It is shown that the consideration of atmospheric density uncertainty and gravity uncertainty significantly improves the quality of the orbit determination and thus makes a contribution to future spaceflight safety by increasing the reliability of the uncertainty estimates used for collision risk assessment.
Biological soil crusts (BSCs) are thin microbiological vegetation layers that naturally develop in unfavorable higher plant conditions (i.e., low precipitation rates and high temperatures) in global drylands. They consist of poikilohydric organisms capable of adjusting their metabolic activities depending on the water availability. However, they, and with them, their ecosystem functions, are endangered by climate change and land-use intensification. Remote sensing (RS)-based studies estimated the BSC cover in global drylands through various multispectral indices, and few of them correlated the BSCs’ activity response to rainfall. However, the allocation of BSCs is not limited to drylands only as there are areas beyond where smaller patches have developed under intense human impact and frequent disturbance. Yet, those areas were not addressed in RS-based studies, raising the question of whether the methods developed in extensive drylands can be transferred easily. Our temperate climate study area, the ‘Lieberoser Heide’ in northeastern Germany, is home to the country’s largest BSC-covered area. We applied a Random Forest (RF) classification model incorporating multispectral Sentinel-2 (S2) data, indices derived from them, and topographic information to spatiotemporally map the BSC cover for the first time in Central Europe. We further monitored the BSC response to rainfall events over a period of around five years (June 2015 to end of December 2020). Therefore, we combined datasets of gridded NDVI as a measure of photosynthetic activity with daily precipitation data and conducted a change detection analysis. With an overall accuracy of 98.9%, our classification proved satisfactory. Detected changes in BSC activity between dry and wet conditions were found to be significant. Our study emphasizes a high transferability of established methods from extensive drylands to BSC-covered areas in the temperate climate. Therefore, we consider our study to provide essential impulses so that RS-based biocrust mapping in the future will be applied beyond the global drylands.
Promoting sustainable lifestyles through Education for Sustainable Development (ESD) is part of the UN’s Agenda 2030. Earlier empirical studies proved direct interactions with and in natural environments to be effective ESD methods. Pandemic-related lockdowns rendered such courses nearly impossible, which raised concerns about achieving the Sustainable Development Goals (SDGs) in general. To evaluate what young learners know about the concept sustainability so far and how it can be taught effectively online, we designed an online learning module tackling sustainability issues and compared it with data from an on-site intervention module for Bavarian 5th graders (~ 10 years old). Cognitive learning as well as attitudinal preferences of 288 learners were monitored in a pretest–posttest design. The learning module comprised two sections: One about botany, plant characteristics, and plant families; the other about the advantages and disadvantages of traditional as well as sustainable farming methods. The customized cognitive test and semantic differentials for sustainability and environmental protection produced three major findings: (1) A digital learning environment successfully and significantly increased sustainability knowledge (2) Learners clearly distinguished the concepts Sustainability and Environmental Protection (3) There is no direct correlation between semantic differential scores and learning outcome.
Vaccination hesitancy is a threat to herd immunity. Healthcare workers (HCWs) play a key role in promoting Coronavirus disease 2019 (COVID-19) vaccination in the general population. We therefore aimed to provide data on COVID-19 vaccination acceptance/hesitancy among German HCWs. For this exploratory, cross-sectional study, an online survey was conducted in February 2021. The survey included 54 items on demographics; previous vaccination behavior; trust in vaccines, physicians, the pharmaceutical industry and health politics; fear of adverse effects; assumptions regarding the consequences of COVID-19; knowledge about vaccines; and information seeking behavior. Odds ratios with 95% confidence intervals were calculated and chi-square tests were performed. Four thousand five hundred surveys were analyzed. The overall vaccination acceptance was 91.7%. The age group ≤20 years showed the lowest vaccination acceptance. Factors associated with vaccination hesitancy were lack of trust in authorities and pharmaceutical companies. Attitudes among acquaintances were associated with vaccination hesitancy too. Participants with vaccination hesitancy more often obtained information about COVID-19 vaccines via messenger services or online video platforms and underperformed in the knowledge test. We found high acceptance amongst German HCWs. Several factors associated with vaccination hesitancy were identified which could be targeted in HCW vaccination campaigns.
Arrhythmogenic cardiomyopathy (ACM) is characterized by fibro-fatty replacement of the myocardium, heart failure and life-threatening ventricular arrhythmias. Causal mutations were identified in genes encoding for proteins of the desmosomes, predominantly plakophilin-2 (PKP2) and desmoglein-2 (DSG2). We generated gene-edited knock-out iPSC lines for PKP2 (JMUi001-A-2) and DSG2 (JMUi001-A-3) using the CRISPR/Cas9 system in a healthy control iPSC background (JMUi001A). Stem cell-like morphology, robust expression of pluripotency markers, embryoid body formation and normal karyotypes confirmed the generation of high quality iPSCs to provide a novel isogenic human in vitro model system mimicking ACM when differentiated into cardiomyocytes.
Formation and treatment of biofilms present a great challenge for health care and industry. About 80% of human infections are associated with biofilms including biomaterial centered infections, like infections of prosthetic heart valves, central venous catheters, or urinary catheters. Additionally, biofilms can cause food and drinking water contamination. Biofilm research focusses on application of experimental biofilm models to study initial adherence processes, to optimize physico-chemical properties of medical materials for reducing interactions between materials and bacteria, and to investigate biofilm treatment under controlled conditions. Exploring new antimicrobial strategies plays a key role in a variety of scientific disciplines, like medical material research, anti-infectious research, plant engineering, or wastewater treatment. Although a variety of biofilm models exist, there is a lack of standardization for experimental protocols, and designing experimental setups remains a challenge. In this study, a number of experimental parameters critical for material research have been tested that influence formation and stability of an experimental biofilm using the non-pathogenic model strain of Pseudomonas fluorescens. These parameters include experimental time frame, nutrient supply, inoculum concentration, static and dynamic cultivation conditions, material properties, and sample treatment during staining for visualization of the biofilm. It was shown, that all tested parameters critically influence the experimental biofilm formation process. The results obtained in this study shall support material researchers in designing experimental biofilm setups.
Clearly, in nature, but also in technological applications, complex systems built in an entirely ordered and regular fashion are the exception rather than the rule. In this thesis we explore how critical phenomena are influenced by quenched spatial randomness. Specifically, we consider physical systems undergoing a continuous phase transition in the presence of topological disorder, where the underlying structure, on which the system evolves, is given by a non-regular, discrete lattice. We therefore endeavour to achieve a thorough understanding of the interplay between collective dynamics and quenched randomness.
According to the intriguing concept of universality, certain laws emerge from collectively behaving many-body systems at criticality, almost regardless of the precise microscopic realization of interactions in those systems. As a consequence, vastly different phenomena show striking similarities at their respective phase transitions. In this dissertation we pursue the question of whether the universal properties of critical phenomena are preserved when the system is subjected to topological perturbations. For this purpose, we perform numerical simulations of several prototypical systems of statistical physics which show a continuous phase transition. In particular, the equilibrium spin-1/2 Ising model and its generalizations represent -- among other applications -- fairly natural approaches to model magnetism in solids, whereas the non-equilibrium contact process serves as a toy model for percolation in porous media and epidemic spreading. Finally, the Manna sandpile model is strongly related to the concept of self-organized criticality, where a complex dynamic system reaches a critical state without fine-tuning of external variables.
Our results reveal that the prevailing understanding of the influence of topological randomness on critical phenomena is insufficient. In particular, by considering very specific and newly developed lattice structures, we are able to show that -- contrary to the popular opinion -- spatial correlations in the number of interacting neighbours are not a key measure for predicting whether disorder ultimately alters the behaviour of a given critical system.
Background and purpose
Improving understanding of study contents and procedures might enhance recruitment into studies and retention during follow-up. However, data in stroke patients on understanding of the informed consent (IC) procedure are sparse.
Methods
We conducted a cross-sectional study among ischemic stroke patients taking part in the IC procedure of an ongoing cluster-randomized secondary prevention trial. All aspects of the IC procedure were assessed in an interview using a standardized 20-item questionnaire. Responses were collected within 72 h after the IC procedure and analyzed quantitatively and qualitatively. Participants were also asked their main reasons for participation.
Results
A total of 146 stroke patients (65 ± 12 years old, 38% female) were enrolled. On average, patients recalled 66.4% (95% confidence interval = 65.2%–67.5%) of the content of the IC procedure. Most patients understood that participation was voluntary (99.3%) and that they had the right to withdraw consent (97.1%); 79.1% of the patients recalled the study duration and 56.1% the goal. Only 40.3% could clearly state a benefit of participation, and 28.8% knew their group allocation. Younger age, higher graduation, and allocation to the intervention group were associated with better understanding. Of all patients, 53% exclusively stated a personal and 22% an altruistic reason for participation.
Conclusions
Whereas understanding of patient rights was high, many patients were unable to recall other important aspects of study content and procedures. Increased attention to older and less educated patients may help to enhance understanding in this patient population. Actual recruitment and retention benefit of an improved IC procedure remains to be tested in a randomized trial.
Sex determination (SD) is a highly diverse and complex mechanism. In vertebrates, one of the first morphological differences between the sexes is the timing of initiation of the first meiosis, where its initiation occurs first in female and later in male. Thus, SD is intimately related to the responsiveness of the germ cells to undergo meiosis in a sex-specific manner. In some vertebrates, it has been reported that the timing for meiosis entry would be under control of retinoic acid (RA), through activation of Stra8. In this study, we used a fish model species for sex determination and lacking the stra8 gene, the Japanese medaka (Oryzias latipes), to investigate the connection between RA and the sex determination pathway. Exogenous RA treatments act as a stress factor inhibiting germ cell differentiation probably by activation of dmrt1a and amh. Disruption of the RA degrading enzyme gene cyp26a1 induced precocious meiosis and oogenesis in embryos/hatchlings of female and even some males. Transcriptome analyzes of cyp26a1–/–adult gonads revealed upregulation of genes related to germ cell differentiation and meiosis, in both ovaries and testes. Our findings show that germ cells respond to RA in a stra8 independent model species. The responsiveness to RA is conferred by sex-related genes, restricting its action to the sex differentiation period in both sexes.
In this paper, I consider the relevance of judgment for practical considerations by discussing Christian August Crusius’s conception of rational desire. According to my interpretation of Crusius’s distinction between rational and non-rational desire, we are responsible at least for our rational desires insofar as we can control them. And we can control our rational desires by judging whether what we want complies with our human nature. It should become clear that Crusius’s conception of rational desire is normative in that we necessarily desire things that are compatible with our nature, such as our own perfection. Therefore, a desire is rational if the desired object is apt to satisfy the desires compatible with our nature. From a contemporary perspective, such a normative conception of rational desire might not appear very attractive; it is apt, however, to stimulate a debate on the normative criteria and the role of judgment for rational desire, which is the ultimate aim of this paper.
Cryptic species and hidden ecological interactions of halictine bees along an elevational gradient
(2021)
Changes of abiotic and biotic conditions along elevational gradients represent serious challenges to organisms which may promote the turnover of species, traits and biotic interaction partners. Here, we used molecular methods to study cuticular hydrocarbon (CHC) profiles, biotic interactions and phylogenetic relationships of halictid bees of the genus Lasioglossum along a 2,900 m elevational gradient at Mt. Kilimanjaro, Tanzania. We detected a strong species turnover of morphologically indistinguishable taxa with phylogenetically clustered cryptic species at high elevations, changes in CHC profiles, pollen resource diversity, and a turnover in the gut and body surface microbiome of bees. At high elevations, increased proportions of saturated compounds in CHC profiles indicate physiological adaptations to prevent desiccation. More specialized diets with higher proportions of low‐quality Asteraceae pollen imply constraints in the availability of food resources. Interactive effects of climatic conditions on gut and surface microbiomes, CHC profiles, and pollen diet suggest complex feedbacks among abiotic conditions, ecological interactions, physiological adaptations, and phylogenetic constraints as drivers of halictid bee communities at Mt. Kilimanjaro.
Locoregional recurrence is a major reason for therapy failure after surgical resection of head and neck squamous cell carcinoma (HNSCC). The physiological process of postoperative wound healing could potentially support the proliferation of remaining tumor cells. The aim of this study was to evaluate the influence of wound fluid (WF) on the cell cycle distribution and a potential induction of epithelial-mesenchymal transition (EMT). To verify this hypothesis, we incubated FaDu and HLaC78 cells with postoperative WF from patients after neck dissection. Cell viability in dependence of WF concentration and cisplatin was measured by flow cytometry. Cell cycle analysis was performed by flow cytometry and EMT-marker expression by rtPCR. WF showed high concentrations of interleukin (IL)-6, IL-8, IL-10, CCL2, MCP-1, EGF, angiogenin, and leptin. The cultivation of tumor cells with WF resulted in a significant increase in cell proliferation without affecting the cell cycle. In addition, there was a significant enhancement of the mesenchymal markers Snail 2 and vimentin, while the expression of the epithelial marker E-cadherin was significantly decreased. After cisplatin treatment, tumor cells incubated with WF showed a significantly higher resistance compared with the control group. The effect of cisplatin-resistance was dependent on the WF concentration. In summary, proinflammatory cytokines are predominantly found in WF. Furthermore, the results suggest that EMT can be induced by WF, which could be a possible mechanism for cisplatin resistance.
In recent years, a paradigm shift from single-photon-emitting radionuclide radiotracers toward positron-emission tomography (PET) radiotracers has occurred in nuclear oncology. Although PET-based molecular imaging of the kidneys is still in its infancy, such a trend has emerged in the field of functional renal radionuclide imaging. Potentially allowing for precise and thorough evaluation of renal radiotracer urodynamics, PET radionuclide imaging has numerous advantages including precise anatomical co-registration with CT images and dynamic three-dimensional imaging capability. In addition, relative to scintigraphic approaches, PET can allow for significantly reduced scan time enabling high-throughput in a busy PET practice and further reduces radiation exposure, which may have a clinical impact in pediatric populations. In recent years, multiple renal PET radiotracers labeled with C-11, Ga-68, and F-18 have been utilized in clinical studies. Beyond providing a precise non-invasive read-out of renal function, such radiotracers may also be used to assess renal inflammation. This manuscript will provide an overview of renal molecular PET imaging and will highlight the transformation of conventional scintigraphy of the kidneys toward novel, high-resolution PET imaging for assessing renal function. In addition, future applications will be introduced, e.g. by transferring the concept of molecular image-guided diagnostics and therapy (theranostics) to the field of nephrology.
Atopic dermatitis (AD) is one of the most prevalent inflammatory disease among non-fatal skin diseases, affecting up to one fifth of the population in developed countries. AD is characterized by recurrent pruritic and localized eczema with seasonal fluctuations. AD initializes the phenomenon of atopic march, during which infant AD patients are predisposed to progressive secondary allergies such as allergic rhinitis, asthma, and food allergies. The pathophysiology of AD is complex; onset of the disease is caused by several factors, including strong genetic predisposition, disrupted epidermal barrier, and immune dysregulation. AD was initially characterized by defects in the innate immune system and a vigorous skewed adaptive Th2 response to environmental agents; there are compelling evidences that the disorder involves multiple immune pathways. Symptomatic palliative treatment is the only strategy to manage the disease and restore skin integrity. Researchers are trying to more precisely define the contribution of different AD genotypes and elucidate the role of various immune axes. In this review, we have summarized the current knowledge about the roles of innate and adaptive immune responsive cells in AD. In addition, current and novel treatment strategies for the management of AD are comprehensively described, including some ongoing clinical trials and promising therapeutic agents. This information will provide an asset towards identifying personalized targets for better therapeutic outcomes.
Current limitations and perspectives of chimeric antigen receptor-T-cells in acute myeloid leukemia
(2021)
Adoptive transfer of gene-engineered chimeric antigen receptor (CAR)-T-cells has emerged as a powerful immunotherapy for combating hematologic cancers. Several target antigens that are prevalently expressed on AML cells have undergone evaluation in preclinical CAR-T-cell testing. Attributes of an ‘ideal’ target antigen for CAR-T-cell therapy in AML include high-level expression on leukemic blasts and leukemic stem cells (LSCs), and absence on healthy tissues, normal hematopoietic stem and progenitor cells (HSPCs). In contrast to other blood cancer types, where CAR-T therapies are being similarly studied, only a rather small number of AML patients has received CAR-T-cell treatment in clinical trials, resulting in limited clinical experience for this therapeutic approach in AML. For curative AML treatment, abrogation of bulk blasts and LSCs is mandatory with the need for hematopoietic recovery after CAR-T administration. Herein, we provide a critical review of the current pipeline of candidate target antigens and corresponding CAR-T-cell products in AML, assess challenges for clinical translation and implementation in routine clinical practice, as well as perspectives for overcoming them.
Magnetic random access memory (MRAM) technology aims to replace dynamic RAM (DRAM) due to its significantly lower power consumption and non-volatility [Dong08]. During the last couple of years the commercial focus was set on spin-transfer torque MRAM (STT-MRAM) systems, where a current is pushed through a ferromagnetic (FM) free layer and a reference layer which are separated by an insulator. The free layer can be set to parallel or anti-parallel depending on the current direction [Kim11]. Unfortunately these currents have to be quite high which could lead to damages of the tunnel barrier of the magnetic tunnel junction resulting in higher power consumption as well as reliability issues. At this point a new effect, where the current is passed below the ferromagnetic layer stack, can be exploited to change the direction of the free layer magnetization. The effect is known as spin-orbit torque (SOT) and describes the transfer of angular momentum onto an adjacent magnetization either by the spin Hall effect (SHE) or inverse spin galvanic effect (iSGE) [Manchon19]. The latter describes a spin accumulation due to a current. This is similar to the process of spin accumulation in TIs, where a current corresponds to an effective spin due to spin-momentum locking [Qi11]. Thus TIs exhibit a high current-to-spin conversion rate, which makes them a promising material system for SOT experiments. Among all TIs it is HgTe, which can be reliably grown as an insulator. This thesis covers the development of a working device for SOT measurements (SOT-device) in a CdTe/CdHgTe/HgTe/CdHgTe heterostructure. It involves the development of a tunnel barrier (ZrOx) as well as the investigation of the behavior of a ferromagnetic layer stack on top of etched HgTe. The main result of this work is the successful construction and evaluation of a working SOT-device, which exhibits the up to date most efficient switching of in-plane magnetized ferromagnetic layer stacks.
In order to avoid hybridization between HgTe and the adjacent ferromagnetic atoms, which would cause a breakdown of the topological surface state, it is necessary to implement a thin tunnel barrier in between the TI and free layer [Zhang16]. Aside from hybridization a tunnel barrier avoids shunting of the current, that is pushed on the surface of the HgTe/CdHgTe interface. Thus a bigger part of the current can be used for spin accumulation and, at the same time, the resistance measurement of the ferromagnetic layer stack is not perturbed. In chapter 3 the focus is set on investigating the tunneling characteristics of ZrOx on top of dry etched HgTe. Thin barriers are used as the interaction of the current generated spin and the adjacent magnetization decreases with distance. On the other hand too small insulator thicknesses lead to leakage currents which disturb heavily the measurement of the resistance of the ferromagnetic layer stack. Thus an optimum thickness of 10 ALD cycles (\(d\approx 1.6\rm\, nm\)) is determined which yields a resistance area product of \(R\cdot A \approx 3\rm\, k\Omega\mu m^{2}\). This corresponds to a tunneling resistance of \(R_{T}\approx 20\rm\, k\Omega\) over a structure surface of \(A_{T} = 0.12\rm\, \mu m^2\). Multiple samples with different thicknesses have been produced. All samples have been examined on their tunneling behavior. The resistance area product as a function of thickness shows a linear behavior on a logarithmic scale. Furthermore all working samples show non-linear I-V curves as well as parabolic dI/dV-curves. Additionally the tunneling resistance \(R_{T}\) increases with decreasing temperature. All above mentioned properties are typical for tunnel barriers which do not include pinholes [Jonsson00]. The last part of chapter 3 deals with thermal properties of HgTe. By measuring the second harmonic of a biasing AC current in the channel below the tunnel barrier it is attempted to extract the diffusion thermopower of the heated electrons. Unfortunately the measured signal showed a far superior contribution of the first harmonic. According to electric circuit simulations a small asymmetry in the barrier (penetration and leaving point of electrons) could be responsible for this behavior.
A ferromagnetic layer stack, consisting of PY/Cu/CoFe, serves as a sensor for magnetization changes due to external fields and current induced spin accumulations. The layer stack exhibits a giant magnetoresistance (GMR) which has been measured by a resistance bridge. The biggest peculiarity in depositing a GMR stack on top of HgTe is that its easy axis forms along only one of the crystal axes (\((110)\) or \((1\overline{1}0)\)). The reason for this anisotropy is still unclear. Sources such as an influence of the terminating material, miscut, furrows during IBE or sputter ripples have been ruled out. It can be speculated that the surface states due to HgTe might have an influence on the development of this easy axis but this would need further investigation. A consequence of this unexpected anisotropy is that every CdTe/CdHgTe/HgTe/CdHgTe wafer has first to be characterized in SQUID in order to find the easy axis. A ferromagnetic resonance (FMR) measurement confirmed this observation. The shape of the ferromagnetic layer stack is chosen to be an ellipse in order to support the easy axis direction by shape anisotropy. Over 8 million ellipses are used to generate a SQUID signal of \(m > 10^{-5}\rm\, emu\). This is sufficient to extract the main characteristics of an average nano pillar under the influence of an external magnetic field. As in the case of bigger structures the ellipse shaped structure shows a step-like behavior. A measured minor loop confirms the existence of the irreversible anti-parallel stable magnetic state. Furthermore this state persists for both directions at \(m=0\) resulting in an anti-ferromagnetic coupling between Py and CoFe.
The geometry of the SOT-device is chosen in such a way that the current induced spin aligns either parallel or anti-parallel to the effective magnetic field \(\vec{B}_{eff}=\vec{B}_{ext}+\vec{B}_{aniso}+\vec{B}_{shape}\), which acts on the pillar. Due to interaction of the spin with the adjacent magnetization of Py the magnetization direction gets changed by a torque \(\vec{T}\). In general this torque can be decomposed into two components a field-like torque \(\vec{\tau}_{FL}\) and a damping-like torque \(\vec{\tau}_{DL}\) [Manchon19]. In the case of TIs \(\vec{T}\) is additionally depending on the z-component of \(\vec{m}\) [Ndiaye17]. In our case the magnetization is lying in the sample plane (\(m_{z}=0\)) which results in \(\vec{\tau}_{DL}=0\). Thus, in the case of \(\vec{S}\parallel\left(\vec{\hat{z}}\times\vec{j}\right)\) and \(\vec{j}\parallel\vec{\hat{y}}\), the only spin dependent effective magnetic field is \(\vec{B}_{FL}=\tau_{FL}\cdot\vec{\hat{x}}\) which is lying parallel or anti-parallel to \(\vec{B}_{eff}\). The evaluation of \(\vec{B}_{FL}\) can therefore be done in the following manner. First a high \(B_{ext}\) has to be set along the easy axis of the pillar. Then \(B_{ext}\) has to be reduced just a few \(\rm\, Oe\) before the switching occurs at the magnetic field \(B_{ext,0}\). At the magnetic field \(\Delta B = B_{ext}-B_{ext,0}\approx 0.5\rm\, Oe\) the lower resistive state should be stable over a longer time range (\(10-30\rm\, min\)) in order to exclude switching due to fluctuations. Now a positive or negative current can be pushed through the channel below the pillar. For one of the two current directions the magnetization of Py switches. It is therefore not a thermal effect that drives the change of \(\vec{m}\). Current densities that are able to switch \(\vec{m}\) at small \(\Delta B\neq 0\) lie in the range of \(j\approx 10^{4}\rm\, A/cm^{2}\). In all experiments the switching efficiency \(\Delta B/j\) decreases with rising \(j\). Furthermore the efficiency as a function of \(j\) depends on the temperature as \(\Delta B/j\) values tend to be up to 20 times higher at \(T=1.8\rm\, K\) and \(j\approx 0\) than at \(T=4.2\rm\, K\). This temperature dependence suggests that switching occurs not due to Oersted fields. Furthermore the Biot-Savart fields had been calculated for four different models: an infinite long rectangular wire, two infinite planes, a full volume and two thin volume planes. Every model shows an efficiency, which is at least three times lower than the observation.
The highest efficiencies in our samples show up to 10 times higher values than in heavy-metal/ferromagnets heterostructures. In contrast to measurement procedures of most other groups our method leads to direct determination of SOT parameters like the effective magnetic field \(\vec{B}_{FL}\). Other groups make use of spin-transfer FMR (ST-FMR) where they AC bias their structure and extract SOT parameters (like \(\tau_{FL}\) and \(\tau_{DL}\)) from second harmonics by fitting theoretical models. Material systems consisting of TIs and magnetic insulators (MIs) on the other hand show 10 times higher efficiencies [Khang18,Li19]. In those cases the magnetization points out of the sample plane which is conceptually different from in-plane magnetic anisotropy geometries like in our case. The greatest benefit in-plane magnetic anisotropy systems is its easy realisation [Bhatti17]. Here only an elliptical shape has to be lithographically implemented instead of conducting research on the appropriate combination of material systems that result in perpendicular magnetic anisotropies [Apalkov16]. Despite the fact that in our case only \(\vec{\tau}_{FL}\) acts as the driving force for changing \(m\) our device still exhibits the up to date highest efficiencies in the class of in-plane magnetized anisotropies of all material classes ever recorded.
Purpose: Patient-specific, flanged acetabular components are used for the treatment of Paprosky type III defects during revision total hip arthroplasty (THA). This monocentric retrospective cohort study analyzes the outcome of patients treated with custom made monoflanged acetabular components (CMACs) with intra- and extramedullary iliac fixation. Methods: 14 patients were included who underwent revision THA with CMACs for the treatment of Paprosky type III defects. Mechanism of THA failure was infection in 4 and aseptic loosening in 10 patients. Seven patients underwent no previous revision, the other seven patients underwent three or more previous revisions. Results: At a mean follow-up of 35.4 months (14–94), the revision rate of the implant was 28.3%. Additionally, one perioperative dislocation and one superficial wound infection occurred. At one year postoperatively, we found a significant improvement of the Western Ontario and McMaster Universities Arthritis Index (WOMAC) score (p = 0.015). Postoperative radiographic analysis revealed good hip joint reconstruction with a mean leg length discrepancy of 3 mm (−8–20), a mean lateralization of the horizontal hip center of rotation of 8 mm (−8–35), and a mean proximalization of the vertical hip center of rotation of 6 mm (13–26). Radiolucency lines were present in 30%. Conclusion: CMACs can be considered an option for the treatment of acetabular bone loss in revision THA. Iliac intra- and extramedullary fixation allows soft tissue-adjusted hip joint reconstruction and improves hip function. However, failure rates are high, with periprosthetic infection being the main threat to successful outcome.
The mason wasp Odynerus spinipes shows an exceptional case of intrasexual cuticular hydrocarbon (CHC) profile dimorphism. Females of this species display one of two CHC profiles (chemotypes) that differ qualitatively and quantitatively from each other. The ratio of the two chemotypes was previously shown to be close to 1:1 at three sites in Southern Germany, which might not be representative given the Palearctic distribution of the species. To infer the frequency of the two chemotypes across the entire distributional range of the species, we analyzed with GC–MS the CHC profile of 1042 dry-mounted specimens stored in private and museum collections. We complemented our sampling by including 324 samples collected and preserved specifically for studying their CHCs. We were capable of reliably identifying the chemotypes in 91% of dry-mounted samples, some of which collected almost 200 years ago. We found both chemotypes to occur in the Far East, the presumed glacial refuge of the species, and their frequency to differ considerably between sites and geographic regions. The geographic structure in the chemotype frequencies could be the result of differential selection regimes and/or different dispersal routes during the colonization of the Western Palearctic. The presented data pave the route for disentangling these factors by providing information where to geographically sample O. spinipes for population genetic analyses. They also form the much-needed basis for future studies aiming to understand the evolutionary and geographic origin as well as the genetics of the astounding CHC profile dimorphism that O. spinipes females exhibit.
Megakaryocytes (MKs) release platelets into the lumen of bone marrow (BM) sinusoids while remaining to reside within the BM. The morphogenetic events of this complex process are still not fully understood. We combined confocal laser scanning microscopy with transmission and serial block-face scanning electron microscopy followed by 3D-reconstruction on mouse BM tissue sections. These analyses revealed that MKs in close vicinity to BM sinusoid (BMS) wall first induce the lateral retraction of CXCL12-abundant reticular (CAR) cells (CAR), followed by basal lamina (BL) degradation enabling direct MK-sinusoidal endothelial cells (SECs) interaction. Subsequently, an endothelial engulfment starts that contains a large MK protrusion. Then, MK protrusions penetrate the SEC, transmigrate into the BMS lumen and form proplatelets that are in direct contact to the SEC surface. Furthermore, such processes are induced on several sites, as observed by 3D reconstructions. Our data demonstrate that MKs in interaction with CAR-cells actively induce BMS wall alterations, including CAR-cell retraction, BL degradation, and SEC engulfment containing a large MK protrusion. This results in SEC penetration enabling the migration of MK protrusion into the BMS lumen where proplatelets that are adherent to the luminal SEC surface are formed and contribute to platelet release into the blood circulation.
We aimed to elucidate the diagnostic potential of the C-X-C motif chemokine receptor 4 (CXCR4)-directed positron emission tomography (PET) tracer \(^{68}\)Ga-Pentixafor in patients with poorly differentiated neuroendocrine carcinomas (NEC), relative to the established reference standard \(^{18}\)F-FDG PET/computed tomography (CT). In our database, we retrospectively identified 11 treatment-naïve patients with histologically proven NEC, who underwent \(^{18}\)F-FDG and CXCR4-directed PET/CT for staging and therapy planning. The images were analyzed on a per-patient and per-lesion basis and compared to immunohistochemical staining (IHC) of CXCR4 from PET-guided biopsies. \(^{68}\)Ga-Pentixafor visualized tumor lesions in 10/11 subjects, while \(^{18}\)F-FDG revealed sites of disease in all 11 patients. Although weak to moderate CXCR4 expression could be corroborated by IHC in 10/11 cases, \(^{18}\)F-FDG PET/CT detected significantly more tumor lesions (102 vs. 42; total lesions, n = 107; p < 0.001). Semi-quantitative analysis revealed markedly higher 18F-FDG uptake as compared to \(^{68}\)Ga-Pentixafor (maximum and mean standardized uptake values (SUV) and tumor-to-background ratios (TBR) of cancerous lesions, SUVmax: 12.8 ± 9.8 vs. 5.2 ± 3.7; SUVmean: 7.4 ± 5.4 vs. 3.1 ± 3.2, p < 0.001; and, TBR 7.2 ± 7.9 vs. 3.4 ± 3.0, p < 0.001). Non-invasive imaging of CXCR4 expression in NEC is inferior to the reference standard \(^{18}\)F-FDG PET/CT.
Methionine restriction (MetR) is an efficient method of amino acid restriction (AR) in cells and organisms that induces low energy metabolism (LEM) similar to caloric restriction (CR). The implementation of MetR as a therapy for cancer or other diseases is not simple since the elimination of a single amino acid in the diet is difficult. However, the in vivo turnover rate of cysteine is usually higher than the rate of intake through food. For this reason, every cell can enzymatically synthesize cysteine from methionine, which enables the use of specific enzymatic inhibitors. In this work, we analysed the potential of cysteine restriction (CysR) in the murine cell line L929. This study determined metabolic fingerprints using mass spectrometry (LC/MS). The profiles were compared with profiles created in an earlier work under MetR. The study was supplemented by proliferation studies using D-amino acid analogues and inhibitors of intracellular cysteine synthesis. CysR showed a proliferation inhibition potential comparable to that of MetR. However, the metabolic footprints differed significantly and showed that CysR does not induce classic LEM at the metabolic level. Nevertheless, CysR offers great potential as an alternative for decisive interventions in general and tumour metabolism at the metabolic level.
Medulloblastoma is the most common high-grade brain tumor in childhood. Medulloblastomas with c-myc amplification, classified as group 3, are the most aggressive among the four disease subtypes resulting in a 5-year overall survival of just above 50%. Despite current intensive therapy regimens, patients suffering from group 3 medulloblastoma urgently require new therapeutic options. Using a recently established c-myc amplified human medulloblastoma cell line, we performed an in-vitro-drug screen with single and combinatorial drugs that are either already clinically approved or agents in the advanced stage of clinical development. Candidate drugs were identified in vitro and then evaluated in vivo. Tumor growth was closely monitored by BLI. Vessel development was assessed by 3D light-sheet-fluorescence-microscopy. We identified the combination of gemcitabine and axitinib to be highly cytotoxic, requiring only low picomolar concentrations when used in combination. In the orthotopic model, gemcitabine and axitinib showed efficacy in terms of tumor control and survival. In both models, gemcitabine and axitinib were better tolerated than the standard regimen comprising of cisplatin and etoposide phosphate. 3D light-sheet-fluorescence-microscopy of intact tumors revealed thinning and rarefication of tumor vessels, providing one explanation for reduced tumor growth. Thus, the combination of the two drugs gemcitabine and axitinib has favorable effects on preventing tumor progression in an orthotopic group 3 medulloblastoma xenograft model while exhibiting a favorable toxicity profile. The combination merits further exploration as a new approach to treat high-risk group 3 medulloblastoma.
The DAEDALUS mission concept aims at exploring and characterising the entrance and initial part of Lunar lava tubes within a compact, tightly integrated spherical robotic device, with a complementary payload set and autonomous capabilities.
The mission concept addresses specifically the identification and characterisation of potential resources for future ESA exploration, the local environment of the subsurface and its geologic and compositional structure.
A sphere is ideally suited to protect sensors and scientific equipment in rough, uneven environments.
It will house laser scanners, cameras and ancillary payloads.
The sphere will be lowered into the skylight and will explore the entrance shaft, associated caverns and conduits. Lidar (light detection and ranging) systems produce 3D models with high spatial accuracy independent of lighting conditions and visible features.
Hence this will be the primary exploration toolset within the sphere.
The additional payload that can be accommodated in the robotic sphere consists of camera systems with panoramic lenses and scanners such as multi-wavelength or single-photon scanners.
A moving mass will trigger movements.
The tether for lowering the sphere will be used for data communication and powering the equipment during the descending phase.
Furthermore, the connector tether-sphere will host a WIFI access point, such that data of the conduit can be transferred to the surface relay station. During the exploration phase, the robot will be disconnected from the cable, and will use wireless communication.
Emergency autonomy software will ensure that in case of loss of communication, the robot will continue the nominal mission.
Im Rahmen dieser Arbeit war es möglich, diverse dinukleare Platinphosphankomplexe darzustellen, wodurch unteranderem neuartige unsymmetrische (N- Aminoboryl)aminoboryl Pt-Komplexe, Borandiyl- und Diboran-1,2-diyl-verbrückte Diplatin-A-Frame Komplexe synthetisiert und charakterisiert werden konnten. Der abschließende Teil dieser Arbeit befasst sich mit den ersten Versuchen zur Darstellung von Polyboranen durch eine Palladium-vermittelte Kreuzkupplungsreaktion.