@article{MansourSteigerNageletal.2019,
  author    = {Mansour, Ahmed M. and Steiger, Christoph and Nagel, Christoph and Schatzschneider, Ulrich},
  title     = {Wavelength-dependent control of the CO release kinetics of manganese(I) tricarbonyl PhotoCORMs with benzimidazole coligands},
  series = {European Journal of Inorganic Chemistry},
  volume    = {2019},
  journal   = {European Journal of Inorganic Chemistry},
  number    = {42},
  doi       = {10.1002/ejic.201900894},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-218362},
  pages     = {4572-4581},
  year      = {2019},
  abstract  = {A series of photoactivatable CO-releasing molecules (PhotoCORMs) was prepared from manganese pentacarbonyl bromide and 1H-benzimidazol-2-ylmethyl-(N-phenyl)amine ligands (L) bearing different electron-donating and electron-withdrawing groups R = H, 4-CH\(_3\), 4-OCH\(_3\), 4-Cl, 4-NO\(_2\), 2-, 3-, and 4-COOCH\(_3\) on the phenyl substituent to give octahedral manganese(I) complexes of the general formula [MnBr(CO)\(_3\)(L)]. Aerated DMSO solutions of the compounds are stable in the dark for 16 h with no CO release. However, the compounds rapidly release CO upon illumination at 412-525 nm, depending on the substitution pattern. Its influence on the photophysical and photochemical properties was systematically explored using UV/Vis spectroscopy and CO release measurements with a commercial gas sensor system. In the nitro-substituted compound, the electronically excited state switched from benzimidazole- to phenyl-centered, leading to a markedly different photochemical behavior of this visible-light activated PhotoCORM.},
  language  = {en}
}
@article{ReiterRitterPrinceetal.2012,
  author    = {Reiter, Theresa and Ritter, Oliver and Prince, Martin R. and Nordbeck, Peter and Wanner, Christoph and Nagel, Eike and Bauer, Wolfgang R.},
  title     = {Minimizing Risk of Nephrogenic systemic fibrosis in Cardiovascular Magnetic Resonance},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-75068},
  year      = {2012},
  abstract  = {Nephrogenic Systemic Fibrosis is a rare condition appearing only in patients with severe renal impairment or failure and presents with dermal lesions and involvement of internal organs. Although many cases are mild, an estimated 5 \% have a progressive debilitating course. To date, there is no known effective treatment thus stressing the necessity of ample prevention measures. An association with the use of Gadolinium based contrast agents (GBCA) makes Nephrogenic Systemic Fibrosis a potential side effect of contrast enhanced magnetic resonance imaging and offers the opportunity for prevention by limiting use of gadolinium based contrast agents in renal failure patients. In itself toxic, Gadolinium is embedded into chelates that allow its safe use as a contrast agent. One NSF theory is that Gadolinium chelates distribute into the extracellular fluid compartment and set Gadolinium ions free, depending on multiple factors among which the duration of chelates exposure is directly related to the renal function. Major medical societies both in Europe and in North America have developed guidelines for the usage of GBCA. Since the establishment of these guidelines and the increased general awareness of this condition, the occurrence of NSF has been nearly eliminated. Giving an overview over the current knowledge of NSF pathobiochemistry, pathogenesis and treatment options this review focuses on the guidelines of the European Medicines Agency, the European Society of Urogenital Radiology, the FDA and the American College of Radiology from 2008 up to 2011 and the transfer of this knowledge into every day practice.},
  subject      = {CMR},
  language  = {en}
}
@phdthesis{Nagel2015,
  author    = {Nagel, Christoph},
  title     = {Novel manganese- and molybdenum-based photoactivatable CO-releasing molecules: synthesis and biological activity},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-120376},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2015},
  abstract  = {Since its discovery as a small signaling molecule in the human body, researchers have tried to utilize the beneficial cytoprotective properties of carbon monoxide in therapeutic applications. Initial work focused on the controlled direct application of CO gas. However, to circumvent the disadvantages of this method such as requirement for special equipment, hospitalization of the patient and the risk of overdosing, metal-carbonyl complexes were developed as CO-releasing molecules (CORMs) which are able to deliver CO in a tissue-specific manner. However, upon the release of CO from the metal coordination sphere, complex fragments termed inactivated CORMs (iCORMs) with free coordination sites remain which can undergo nonspecific follow-up reactions under physiological conditions. Thus, the first aim of the present thesis was the coordination of tetradentate ligands such as tris(2-pyridylmethyl)amine (tpa), bis(2-pyridylmethyl)(2-quinolylmethyl)amine (bpqa), bis(2-quinolylmethyl)(2-pyridylmethyl)amine (bqpa) and tris(2-quinolylmethyl) amine (tmqa) in a tridentate facial manner to a fac-Mn(CO)3 moiety previously established as a photoactivatable CO-releasing molecule (PhotoCORM). The desired coordination of the pedant donor group upon photolytic CO release at 365 nm was demonstrated by UV/Vis-, IR- und 1H NMR experiments and verified by DFT calculations. All complexes of the series showed long-term dark stability in phosphate-buffered saline (PBS), but released between two and three equivalents of carbon monoxide with half-lives of around 5-10 minutes upon illumination at 365 nm. Although the photolytic properties of the complexes were quite similar besides the differences in type of hetereoaromatic ligands, the determination of the logP values showed an increase of lipophilicity with the number of quinoline groups, which might enable tissue-specific uptake. A significant cellular manganese uptake as well as the binding of CO released upon photolysis to the cytochrome c oxidases in E. coli cells was demonstrated for [Mn(CO)3(tpa)]+. Furthermore, this complex exhibited photoinduced bactericidal activity when the cells were grown in succinate-containing medium and thus unable to change their metabolism to mixed acid fermentation. In the second part of the project, the hexadentate ligand 1,4,7-tris(2-pyridylmethyl)-1,4,7-triazacyclononane (py3tacn) was coordinated to a facial Mn(CO)3 moiety. The resulting [Mn(CO)3(py3tacn-3N)]+ complex has one pedant donor group per labile carbonyl ligand and thus is a significant improvement over the 1st generation tpa-complexes. The metal-coligand inactivated CORM (iCORM) fragment expected to be generated upon complete photolytic CO release, [Mn(py3tacn-6N)]2+, was synthesized independently and will serve as a well-defined negative control in upcoming biological tests. The corresponding CORM has long-term dark stability in pure dimethylsulfoxide or phosphate-buffered myoglobin solution, with three equivalents of CO released with a half-life of 22 minutes upon illumination at 412 nm. The photolysis was also followed by IR spectroscopy and the intermediates, in line with a stepwise release of carbon monoxide, and occupation of vacated sites by the pedant pyridine group were verified by DFT calculations. Due to possible tissue damage by energy-rich light and the inverse correlation of tissue penetration depth and illumination wavelength, the absorption maxima of PhotoCORMs should ideally be in the phototherapeutic window between 600 and 1200 nm. Thus, in the third part of this work, a series of heterobinuclear Mn(CO)3/Ru(bpy)2 PhotoCORMs was prepared to shift the absorption of these compounds into the red region of the UV/Vis spectrum. For the synthesis of such Mn(I)/Ru(II) complexes, the bridging ligands 2,3-di(2-pyridyl)quinoxaline (dpx) and 3-(pyridin-2-yl)-1,2,4-triazine[5,6-f]-1,10-phenanthroline (pytp) were prepared and the two binding pockets subsequently filled with a Ru(bpy)2 and a fac-Mn(CO)3 moiety. The resulting two heterobinuclear metal complexes [Ru(bpy)2(dpx)MnBr(CO)3]2+ and [Ru(bpy)2(pytp)MnBr(CO)3]2+ as well as [Ru(etx)(tbx)MnBr(CO)3]2+ with etx = ethyl(2,2':6',2''-terpyridine)-4'-carboxylate and tbx = N-((2,2':6',2''-terpyridin)-4'-yl)2,2'-bipyridine-5-carboxamide which was prepared by a metal precursor provided by the group of Prof. Dr. Katja Heinze showed a significant shift of the main absorption bands to higher wavelengths as well as two times higher extinction coefficients than the analogous mononuclear Mn(I) compounds. However, both the Mn(I)/Ru(II) and Mn(I) complexes had a reduced stability in phosphate-buffered myoglobin solution even in the absence of light. The efficiency of the CO-release from [Ru(etx)(tbx)MnBr(CO)3]2+ and [Ru(bpy)2(dpx)MnBr(CO)3]2+ could be controlled by proper choice of the excitation wavelength. A change from 468 to 525 nm or even 660 nm led to a decrease of the number of CO equivalents released from two to one and an elongation of the half-lives. Finally, since nitric oxide also serves as a small messenger molecule in the human body with its signaling pathways interacting with those of CO, a mixed-ligand CO/NO metal complex was sought. [Mo(CO)2(NO)(iPr3tacn)]+ with iPr3tacn = 1,4,7-triisopropyl-1,4,7-triazacyclonane was selected from the literature and its molecular structure determined by single crystal diffraction, demonstrating the presence of an NO+ ligand in the coordination sphere as indicated by a MO-N-O angle close to 180°. Photolysis of [Mo(CO)2(NO)(iPr3tacn)]+ required high-energy UV light, which prevented a quantification of the CO release due to photolytic decomposition of the myoglobin. However, solution IR experiments showed that the complex lost the two carbon monoxide ligands upon illumination at 254 nm while the NO remained tightly bound to the metal. The structures observed of the intermediates were also verified by DFT calculations. In conclusion, in this project, four different classes of novel transition metal-based photoactivatable CO-releasing molecules (PhotoCORMs) were prepared and studied. The first group incorporated one additional free donor group per LMn(CO)3 moiety but varied in the number of coordinated pyridyl and quinolinyl groups which allows the control of the lipophilicity of these compounds. As an extension of this concept, the second series incorporated one free donor group per labile carbonyl ligand which gives rise to well-defined photolysis products that can be independently prepared and assayed. The third class was based on a Ru(II) photosensitizer unit connected to a MnBr(CO)3 PhotoCORM moiety. This shifts the absorption maximum from 500 nm to about 585 nm in [Ru(bpy)2(dpx)MnBr(CO)3]2+. Finally, a first mixed-ligand CO/NO carrier molecule was evaluated for its photolytic behavior. However, while the carbonyl ligands were photolabile at low excitation wavelengths, release of the NO ligand was not observed under the conditions studied. In a next step, detailed studies on the bioactivity of the different classes of PhotoCORMs need to be carried out with partner groups from biochemistry to fully explore their biomedical potential.},
  subject      = {Kohlenmonoxid},
  language  = {en}
}
@article{PagelTwisselmannRauschetal.2020,
  author    = {Pagel, Julia and Twisselmann, Nele and Rausch, Tanja K. and Waschina, Silvio and Hartz, Annika and Steinbeis, Magdalena and Olbertz, Jonathan and Nagel, Kathrin and Steinmetz, Alena and Faust, Kirstin and Demmert, Martin and G{\"o}pel, Wolfgang and Herting, Egbert and Rupp, Jan and H{\"a}rtel, Christoph},
  title     = {Increased Regulatory T Cells Precede the Development of Bronchopulmonary Dysplasia in Preterm Infants},
  series = {Frontiers in Immunology},
  volume    = {11},
  journal   = {Frontiers in Immunology},
  issn      = {1664-3224},
  doi       = {10.3389/fimmu.2020.565257},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-212409},
  year      = {2020},
  abstract  = {Regulatory T cells (Tregs) are important for the ontogenetic control of immune activation and tissue damage in preterm infants. However, the role of Tregs for the development of bronchopulmonary dysplasia (BPD) is yet unclear. The aim of our study was to characterize CD4+ CD25+ forkhead box protein 3 (FoxP3)+ Tregs in peripheral blood of well-phenotyped preterm infants (n = 382; 23 + 0 - 36 + 6 weeks of gestational age) with a focus on the first 28 days of life and the clinical endpoint BPD (supplemental oxygen for longer than 28 days of age). In a subgroup of preterm infants, we characterized the immunological phenotype of Tregs (n = 23). The suppressive function of Tregs on CD4+CD25- T cells was compared in preterm, term and adult blood. We observed that extreme prematurity was associated with increased Treg frequencies which peaked in the second week of life. Independent of gestational age, increased Treg frequencies were noted to precede the development of BPD. The phenotype of preterm infant Tregs largely differed from adult Tregs and displayed an overall na{\"i}ve Treg population (CD45RA+/HLA-DR-/Helios+), especially in the first days of life. On day 7 of life, a more activated Treg phenotype pattern (CCR6+, HLA-DR+, and Ki-67+) was observed. Tregs of preterm neonates had a higher immunosuppressive capacity against CD4+CD25- T cells compared to the Treg compartment of term neonates and adults. In conclusion, our data suggest increased frequencies and functions of Tregs in preterm neonates which display a distinct phenotype with dynamic changes in the first weeks of life. Hence, the continued abundance of Tregs may contribute to sustained inflammation preceding the development of BPD. Functional analyses are needed in order to elucidate whether Tregs have potential as future target for diagnostics and therapeutics.},
  language  = {en}
}
@article{BartelheimNemesSeeringeretal.2016,
  author    = {Bartelheim, Kerstin and Nemes, Karolina and Seeringer, Angela and Kerl, Kornelius and Buechner, Jochen and Boos, Joachim and Graf, Norbert and D{\"u}rken, Matthias and Gerss, Joachim and Hasselblatt, Martin and Kortmann, Rolf-Dieter and Teichert von Luettichau, Irene and Nagel, Inga and Nygaard, Randi and Oyen, Florian and Quiroga, Eduardo and Schlegel, Paul-Gerhardt and Schmid, Irene and Schneppenheim, Reinhard and Siebert, Reiner and Solano-Paez, Palma and Timmermann, Beate and Warmuth-Metz, Monika and Fr{\"u}hwald, Michael Christoph},
  title     = {Improved 6-year overall survival in AT/RT - results of the registry study Rhabdoid 2007},
  series = {Cancer Medicine},
  volume    = {5},
  journal   = {Cancer Medicine},
  number    = {8},
  doi       = {10.1002/cam4.741},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-164799},
  pages     = {1765-1775},
  year      = {2016},
  abstract  = {Atypical teratoid rhabdoid tumors (AT/RT) are characterized by mutations and subsequent inactivation of SMARCB1 (INI1, hSNF5), a predilection for very young children and an unfavorable outcome. The European Registry for rhabdoid tumors (EU-RHAB) was established to generate a common European database and to establish a standardized treatment regimen as the basis for phase I/II trials. Thus, genetic analyses, neuropathologic and radiologic diagnoses, and a consensus treatment regimen were prospectively evaluated. From 2005 to 2009, 31 patients with AT/RT from four countries were recruited into the registry study Rhabdoid 2007 and treated with systemic and intraventricular chemotherapy. Eight patients received high-dose chemotherapy, 23 radiotherapy, and 17 maintenance therapy. Reference evaluations were performed in 64\% (genetic analyses, FISH, MLPA, sequencing) up to 97\% (neuropathology, INI1 stain). Germ-line mutations (GLM) were detected in 6/21 patients. Prolonged overall survival was associated with age above 3 years, radiotherapy and achievement of a complete remission. 6-year overall and event-free survival rates were 46\% (±0.10) and 45\% (±0.09), respectively. Serious adverse events and one treatment-related death due to insufficiency of a ventriculo peritoneal shunt (VP-shunt) and consecutive herniation were noted. Acquisition of standardized data including reference diagnosis and a standard treatment schedule improved data quality along with a survival benefit. Treatment was feasible with significant but manageable toxicity. Although our analysis is biased due to heterogeneous adherence to therapy, EU-RHAB provides the best available basis for phase I/II clinical trials.},
  language  = {en}
}
@article{vomDahlMuellerBerishaetal.2022,
  author    = {vom Dahl, Christian and M{\"u}ller, Christoph Emanuel and Berisha, Xhevat and Nagel, Georg and Zimmer, Thomas},
  title     = {Coupling the cardiac voltage-gated sodium channel to channelrhodopsin-2 generates novel optical switches for action potential studies},
  series = {Membranes},
  volume    = {12},
  journal   = {Membranes},
  number    = {10},
  issn      = {2077-0375},
  doi       = {10.3390/membranes12100907},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-288228},
  year      = {2022},
  abstract  = {Voltage-gated sodium (Na\(^+\)) channels respond to short membrane depolarization with conformational changes leading to pore opening, Na\(^+\) influx, and action potential (AP) upstroke. In the present study, we coupled channelrhodopsin-2 (ChR2), the key ion channel in optogenetics, directly to the cardiac voltage-gated Na\(^+\) channel (Na\(_v\)1.5). Fusion constructs were expressed in Xenopus laevis oocytes, and electrophysiological recordings were performed by the two-microelectrode technique. Heteromeric channels retained both typical Na\(_v\)1.5 kinetics and light-sensitive ChR2 properties. Switching to the current-clamp mode and applying short blue-light pulses resulted either in subthreshold depolarization or in a rapid change of membrane polarity typically seen in APs of excitable cells. To study the effect of individual K\(^+\) channels on the AP shape, we co-expressed either K\(_v\)1.2 or hERG with one of the Na\(_v\)1.5-ChR2 fusions. As expected, both delayed rectifier K\(^+\) channels shortened AP duration significantly. K\(_v\)1.2 currents remarkably accelerated initial repolarization, whereas hERG channel activity efficiently restored the resting membrane potential. Finally, we investigated the effect of the LQT3 deletion mutant ΔKPQ on the AP shape and noticed an extremely prolonged AP duration that was directly correlated to the size of the non-inactivating Na\(^+\) current fraction. In conclusion, coupling of ChR2 to a voltage-gated Na\(^+\) channel generates optical switches that are useful for studying the effect of individual ion channels on the AP shape. Moreover, our novel optogenetic approach provides the potential for an application in pharmacology and optogenetic tissue-engineering.},
  language  = {en}
}
@article{TinajeroTrejoRanaNageletal.2016,
  author    = {Tinajero-Trejo, Mariana and Rana, Namrata and Nagel, Christoph and Jesse, Helen E. and Smith, Thomas W. and Wareham, Lauren K. and Hippler, Michael and Schatzschneider, Ulrich and Poole, Robert K.},
  title     = {Antimicrobial Activity of the Manganese Photoactivated Carbon Monoxide-Releasing Molecule [Mn(CO)\(_3\)(tpa-kappa\(^3\)N)]\(^+\) Against a Pathogenic Escherichia coli that Causes Urinary Infections},
  series = {Antioxidants \& Redox Signaling},
  volume    = {24},
  journal   = {Antioxidants \& Redox Signaling},
  number    = {14},
  doi       = {10.1089/ars.2015.6484},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-188910},
  pages     = {765-780},
  year      = {2016},
  abstract  = {Aims: We set out to investigate the antibacterial activity of a new Mn-based photoactivated carbon monoxide-releasing molecule (PhotoCORM, [Mn(CO)\(_3\)(tpa-kappa\(^3\)N)]\(^+\)) against an antibiotic-resistant uropathogenic strain (EC958) of Escherichia coli. Results: Activated PhotoCORM inhibits growth and decreases viability of E. coli EC958, but non-illuminated carbon monoxide-releasing molecule (CORM) is without effect. NADH-supported respiration rates are significantly decreased by activated PhotoCORM, mimicking the effect of dissolved CO gas. CO from the PhotoCORM binds to intracellular targets, namely respiratory oxidases in strain EC958 and a bacterial globin heterologously expressed in strain K-12. However, unlike previously characterized CORMs, the PhotoCORM is not significantly accumulated in cells, as deduced from the cellular manganese content. Activated PhotoCORM reacts avidly with hydrogen peroxide producing hydroxyl radicals; the observed peroxide-enhanced toxicity of the PhotoCORM is ameliorated by thiourea. The PhotoCORM also potentiates the effect of the antibiotic, doxycycline. Innovation: The present work investigates for the first time the antimicrobial activity of a light-activated PhotoCORM against an antibiotic-resistant pathogen. A comprehensive study of the effects of the PhotoCORM and its derivative molecules upon illumination is performed and mechanisms of toxicity of the activated PhotoCORM are investigated. Conclusion: The PhotoCORM allows a site-specific and time-controlled release of CO in bacterial cultures and has the potential to provide much needed information on the generality of CORM activities in biology. Understanding the mechanism(s) of activated PhotoCORM toxicity will be key in exploring the potential of this and similar compounds as antimicrobial agents, perhaps in combinatorial therapies with other agents.},
  language  = {en}
}
@article{BohmannKurkaduMesnildeRochemontetal.2019,
  author    = {Bohmann, Ferdinand O. and Kurka, Natalia and du Mesnil de Rochemont, Richard and Gruber, Katharina and Guenther, Joachim and Rostek, Peter and Rai, Heike and Zickler, Philipp and Ertl, Michael and Berlis, Ansgar and Poli, Sven and Mengel, Annerose and Ringleb, Peter and Nagel, Simon and Pfaff, Johannes and Wollenweber, Frank A. and Kellert, Lars and Herzberg, Moriz and Koehler, Luzie and Haeusler, Karl Georg and Alegiani, Anna and Schubert, Charlotte and Brekenfeld, Caspar and Doppler, Christopher E. J. and Onur, Oezguer A. and Kabbasch, Christoph and Manser, Tanja and Pfeilschifter, Waltraud},
  title     = {Simulation-based training of the rapid evaluation and management of acute stroke (STREAM) — a prospective single-arm multicenter trial},
  series = {Frontiers in Neurology},
  volume    = {10},
  journal   = {Frontiers in Neurology},
  issn      = {1664-2295},
  doi       = {10.3389/fneur.2019.00969},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-369239},
  year      = {2019},
  abstract  = {Introduction: Acute stroke care delivered by interdisciplinary teams is time-sensitive. Simulation-based team training is a promising tool to improve team performance in medical operations. It has the potential to improve process times, team communication, patient safety, and staff satisfaction. We aim to assess whether a multi-level approach consisting of a stringent workflow revision based on peer-to-peer review and 2-3 one-day in situ simulation trainings can improve acute stroke care processing times in high volume neurocenters within a 6 months period. Methods and Analysis: The trial is being carried out in a pre-test-post-test design at 7 tertiary care university hospital neurocenters in Germany. The intervention is directed at the interdisciplinary multiprofessional stroke teams. Before and after the intervention, process times of all direct-to-center stroke patients receiving IV thrombolysis (IVT) and/or endovascular therapy (EVT) will be recorded. The primary outcome measure will be the "door-to-needle" time of all consecutive stroke patients directly admitted to the neurocenters who receive IVT. Secondary outcome measures will be intervention-related process times of the fraction of patients undergoing EVT and effects on team communication, perceived patient safety, and staff satisfaction via a staff questionnaire. Interventions: We are applying a multi-level intervention in cooperation with three "STREAM multipliers" from each center. First step is a central meeting of the multipliers at the sponsor's institution with the purposes of algorithm review in a peer-to-peer process that is recorded in a protocol and an introduction to the principles of simulation training and debriefing as well as crew resource management and team communication. Thereafter, the multipliers cooperate with the stroke team trainers from the sponsor's institution to plan and execute 2-3 one-day simulation courses in situ in the emergency department and CT room of the trial centers whereupon they receive teaching materials to perpetuate the trainings. Clinical Trial Registration: STREAM is a registered trial at https://clinicaltrials.gov/ct2/show/NCT03228251.},
  language  = {en}
}