Wenige Bereiche der Medizin verzeichnen so gravierende Umwandlungen, wie es die gynäkologische Onkologie aktuell erlebt - vom Paradigmenwechsel der molekulargenetischen Testung hin zur Individualisierung der operativen Radikalität und von der Einführung personalisierter Therapiestrategien bis hin zur interprofessionellen und sektorenübergreifenden Patientenversorgung. Die hier zusammengefassten Arbeiten berichten über die Herausforderungen bei der Etablierung der innovativen Tumorkonferenz „Gynäkologische Malignome“ und stellen erste Ergebnisse einzelner Subprojekte dieser Plattform dar. In einer weiteren Arbeit wird über die praktischen Probleme und Herausforderungen beim Aufbau einer translationalen Patienten- und Biobank im Rahmen des EU-Konsortiums „Ovarian Cancer - Diagnosis of a Silent Killer“ (OVCAD), initiiert an fünf führenden gynäkologisch-onkologischen Krebszentren, berichtet. Weitere wird über erste Erfahrungen mit dem innovativen intraperitonealen Einsatz des trifunktionalen anti-CD3X/anti-EpCAM Antikörpers Catumaxumab, zugelassen für die Behandlung des malignen Aszites, als unmittelbar intraoperative Gabe nach primär zytoreduktiver Chirurgie beim fortgeschrittenen Ovarialkarzinom berichtet. Die Behandlung des multiresistenten Ovarialkarzinomrezidivs stellt uns vor noch größeren Herausforderungen, da einerseits die Therapieoptionen limitiert sind und andererseits die klinische Symptomatik, bedingt durch das Tumorgeschehen und die vorbestehende Toxizitäten, die Lebensqualität massiv einschränken. Deshalb erscheint eine Optimierung der Patientenselektion sinnvoll, um möglichst individualisierte Therapieansätze für verschiedene Subgruppen anbieten zu können, v.a. wenn man die große Anzahl älterer oder fragiler Patientinnen mit dieser Erkrankung berücksichtigen will. In der Präferenz-Studie wurde deshalb speziell auf die Patientinnen-Perspektive als primäres Studienziel fokussiert. In der TRIAS-Studie konnten zum ersten Mal in der Ovarialkarzinom-Forschung die starke klinische Relevanz eines Tyrosinkinase-basierten Kombinations- und Erhaltungsansatzes für das Outcome demonstriert werden. Diese Ergebnisse bestätigen besonders eindrucksvoll das therapeutische Potenzial der Angiogenesehemmung als zielgerichtete Therapiestrategie beim Eierstockkrebs.

In the first part of this thesis, the general coordination and organometallic chemistry of technetium was explored. The preparation and reactivity of technetium hydrido complexes based on an improved synthetic protocol for the scalable synthesis of the technetium(III) hydride [TcH3(PPh3)4] was investigated. As a result, the technetium(I) hydride mer-trans-[TcH(CO)3(PPh3)2] became available in scalable amounts, which led to the isolation of a variety of structurally similar technetium(I) complexes containing two or three carbonyl ligands through its reactions with Brønsted acids. Reactions with Brønsted acids of weakly coordinating counter-ions resulted in the formation of the labile aqua complex mer-trans-[Tc(OH2)(CO)3(PPh3)2]+ that has been used as a labile starting material for ligand exchange reactions with various ligands of general interest to the coordination chemistry of technetium. The non-protic dimethylsulfide surrogate mer-trans-[Tc(SMe2)(CO)3(PPh3)2]+ was developed and successfully used for the preparation of novel organometallic technetium complexes, for example the isolation of the first acetylido complexes of technetium was accomplished. Throughout these studies, a series of structurally related compounds containing the mer-{Tc(CO)3}+ or cis-{Tc(CO)2}+ cores was prepared, that enabled a detailed evaluation of structural relationships among technetium complexes having the same core structure but different ligands. Most importantly, 99Tc NMR spectroscopy was proven as an invaluable and highly specific tool for the analysis of the lowvalent technetium carbonyl species. Besides carbonyl complexes, also the chemistry of the low-valent technetium(I) complexes [Tc(NO)(Cp)(PPh3)Cl] and [TcI(NO)(PPh3)(LOMe)Cl] has been investigated. Finally, the reduction chemistry of pertechnetate in highly acidic media was studied resulting in the characterization of the previously unknown, mixed-valence ammonium polyoxometallate salt (NH4)4[{TcVO(TcVIIO4)4}4]. In the second part of this thesis, the coordination chemistry of organoselenium- and tellurium compounds was studied. A method for the easy and reliable preparation of organochalcogenolato complexes from dichalcogenides and metal phosphine complexes was developed using reductionsensitive Schiff’ base substituted dichalcogenides as model compounds. The coordination of one chalcogen atom of the dichalcogenide increases the reactivity of the second chalcogen atom through an increase in its electropositive σ-hole and, thus, enables the nucleophilic attack of the in situ released reducing agent. The method was expanded from the originally studied rhenium(V) oxido and arylimido complexes to nickel, palladium and platinum complexes in the oxidation state +2. With phosphine-free starting materials, the Schiff’ base substituted dichalcogenides form clusters of varying structure. For the first time, the interconversion of the gyrobifastigial and cuboid-like structures of tetrameric Pd4Chal4 central units for compounds with the same chemical composition has been observed. Lastly, large bowl-shaped telluroxane clusters have been investigated. The coordination of the central unit of each half-shell in the large telluroxane-clusters to calcium in a crown-ether-like fashion led to a loss in color. The shift of the UV-VIS absorption could be explained by DFT calculations due to an increased delocalization of electron density in the telluroxane framework.

The field of optogenetics is in constant development while searching for new optogenetic tools that can be used to control nerve cells, stimulus and optical control of neuronal activity. Among the candidates to be developed as new optogenetics tools, are the LOV (Light Oxygen Voltage) proteins which are ubiquitous photosensors in all domains of life. Channelrhodopsins are frequently used in optogenetics due to their light-gated cation activity, which is a unique characteristic among the ion channels.

Channelrhodopsin-1 from Chlamydomonas augustae (CaChR1) exhibits slower inactivation under continuous illumination and a shift in the visible maximum absorption compared to Channelrhodopsin-1 and Channelrhodopsin-2 from Chlamydomonas reinhardtii. These features are advantageous when developing optogenetic tools, securing CaChR1 as a viable candidate for research. Here, by variation of amino acid chains, an investigation of the molecular changes in the photocycle of CaChR1 was conducted. Steady-state and time-resolved molecular spectroscopy revealed the unusual deprotonated cysteine amino acid (C174) in the ground state. It was also established that C174 plays a central role as the internal proton donor to the retinal Schiff base during the decay of the P2380 intermediate state, which is concomitant with the deprotonation of D299 and protonation of E136 and E169 amino acids.

Among the LOV domains an investigation on a variant of the short LOV protein from Dinoroseobacter shibae was conducted. The DsLOV-M49S has the advantage of having an exceptionally fast photocycle compared to other LOV domains. This unique feature of DsLOV-M49S enables the performance of time-resolved molecular spectroscopy and the characterization of the thio-adduct state’s formation. Using an infrared quantum cascade laser (QCL), the evolution of the weak changes in absorption were successfully tracked for the S-H vibration of a single cysteine residue. The changes indicate the deprotonation of C72 with a time constant of 12 µs, which coincides with the formation of the FMN-cystenyl-thiol-adduct state.

This thesis focuses on a deep biophysical mechanistic investigation of these two systems candidates to optogenetic tools. The experiments performed elucidate the choreographed sequence of proton transfers, changes in electron densities, spin alterations, and transient bond formations and breakages; all of which supplement and refine the mechanistic interpretation of the light-induced structural changes in LOV domains and CaChR1.

During cancer development, malignant tumours accumulate genetic and epigenetic alterations that cause dysregulation of gene expression and cellular processes. Since the regulation of gene expression controls many cellular processes, understanding the transcriptome of malignant tumours provides insights into the biology of cancer. Key technology for the molecular analysis of whole cancer transcriptomes is next- generation sequencing (NGS) of RNA (RNA-seq) from bulk tumours. However, to derive information about cancer transcriptomes from RNA-seq data, a variety of computational tools and analyses are needed. The following work presents two cancer transcriptome studies addressing the computational analysis of RNA-seq data from colorectal carcinomas (CRC) and medulloblastomas (MB) by applying statistical and machine learning (ML) methods.

CRC is a clinically challenging disease because only a fraction of tumours responds to available chemo- and targeted therapies. Functional loss of the tumour suppressor APC has been suggested to represent the initial mutation, activating Wnt signalling. Additional events include mutually exclusive mutations in the RAS/RAF proto-oncogenes as well as in the TGFβ, PI3K, and TP53 pathways. Routinely used biomarkers of resistance to the EGFR inhibitor cetuximab are RAS/RAF mutations that activate signalling downstream of EGFR. Still, a fraction of wild-type CRCs is resistant to cetuximab treatment. Addressing the need for a better molecular understanding of CRC in precision oncology, the OncoTrack consortium (Innovative Medicine Initiative) designed a multi-omics strategy integrating the establishment of a pre-clinical platform for CRC organoid and animal models. In the study presented below, we focused on the integrative analysis of gene expression and drug response data obtained from patient-derived xenografts (PDXs) treated with cetuximab. Applying statistical methods, we identified a signature of 241 genes associated with response to cetuximab, which allowed us to dissect the expression profiles of responding and non-responding CRC. We used a support vector machine (SVM), a supervised ML algorithm, to obtain a gene-expression-based classifier predictive of response to cetuximab. Here, we selected 16 highly predictive genes using multiple SVM recursive feature elimination. The built classifier outperformed RAS/RAF mutations as a predictor of cetuximab response and performed well in RAS/RAF-wild-type CRC that currently lacks biomarkers of cetuximab treatment outcome in clinical practice.

The second study addressed the molecular analysis of MB. MB, a tumour of the cerebellum, is the most common malignant brain tumour in children. Transcriptome profiling of MB using microarrays had revealed four tumour subgroups, namely WNT, SHH, Group 3 and Group 4, each related to distinct genetic alterations, molecular profiles, and clinical features. Recurrent mutations mainly cause pathway activation in WNT and SHH MB, respectively, whereas in Group 3 and Group 4 MB, gross chromosomal alterations are more prevalent and tumours express a specific cell-type- rather than a pathway-related gene signature. Additional molecular complexity has been identified within these four main subgroups, which could be dissected further into subtypes. However, the gene regulatory networks that contribute to the molecular heterogeneity in MB are only partially known, and the role of long non-coding (lnc) genes remains poorly addressed in this disease. To gain further insights into the molecular biology of MB, the PedBrain project was founded within the ICGC framework. As a contribution to this project, we sequenced and computationally analysed 164 MB RNA-seq samples. Addressing the heterogeneity of MB, we identified and validated molecular subclusters within the four main subgroups. Subgroup- and subcluster-specific gene expression profiles were analysed by functional enrichments and gene regulatory networks (GRNs) inferred from gene expression data. These GRNs revealed communalities and differences in gene regulation among subclusters and subgroups. By estimating the impact of TFs, we could unravel master regulators of subcluster-specific gene expression in a systematic fashion for the first time and highlight unknown regulators of Group 4 MB. Furthermore, we characterised lnc genes that were differentially expressed in MB. Among these genes, we identified 20 lnc genes that show brain- development-associated expression patterns, which is of interest due to the embryonic origin of MB. We identified a co-expression cluster that accumulates known cancer-related lnc genes and associates these genes with cancer-promoting protein biogenesis. Survival analyses revealed the lnc gene MEG3 as a prognostic marker in SHH and Group 4 subcluster, potentially acting as a tumour suppressor that negatively regulates cell cycle and TGFβ receptor expression.

Children grow and adapt very obviously and constantly, but they are not the only ones. People change across their whole life span. Empirical evidence shows that also adults’ personality (i.e., openness to experience, conscientiousness, extraversion, agreeableness, neuroticism) and their social participation (e.g., social network size) change up until old age. Even though the phenomenon of lifelong personality trait change is widely accepted, the causes of change and thus the possibilities to intervene are much debated currently. So far, little attention has been paid to the role of social participation with regard to personality change and vice versa. Firstly, this thesis introduces the literature on personality development and social participation over the life span (Chapter 1), followed by a review of the empirical evidence on changes in personality traits and in social behavior, i.e., in-person social contacts, leisure activities (Chapters 2-4). In order to further contribute to research on life span development and catalysts of personality change, the following research questions (RQ) will be investigated: RQ 1. Can an intensive cognitive training change personality trait, especially openness to experience, in the long run? (Study 1, Chapter 2) RQ 2. How does in-person social contact frequency develop across the adult life span? (Study 2, Chapter 3) RQ 3. Are changes in frequency of different leisure activities and overall (social) participation associated with personality change? – If so, which direction do they take? (Study 3, Chapter 4) The data to answer these questions are derived from two data sets. Firstly, the COGITO study that was originally designed to investigate day-to-day fluctuations in cognitive performance and to examine transfer effects of trained cognitive tasks on nontrained cognitive tasks (Chapter 2). Secondly, the German Socio-Economic Panel Study (SOEP), which is a large, ongoing survey of private households and individuals in Germany which was initiated in 1984 (Chapters 3 and 4). The results of the empirical chapters lead to the following answers (A) to the research questions: A 1. Cognitive training does not affect changes in any facet of openness to experience in the long-run. This was true for young and old participants as well as for men and women. A 2. The frequency of in-person contacts with family members remains relatively stable across the life span. The frequency of visits to and from nonfamily members (neighbors, friends, and acquaintances) declines, following a cubic trajectory and drops below the frequency of family visits once people are in their mid-30s. A 3. Frequency of different leisure activities and the overall participation are most strongly associated with openness to experience trait at a between-person level. However, at within-person level, reciprocal effects are discerned only for extraversion with overall participation and socializing (i.e. in-person contacts). These results are integrated into the literature on personality development and social psychology in the general discussion and implications for research and practice are discussed respectively (Chapter 5). In conclusion, this thesis minimizes some gaps in the literature by comprehensively investigating mechanisms of personality change and patterns of social behavior in adulthood.

Die hohe Inzidenz von primären und sekundären hepatischen Tumorerkrankungen kennzeichnet die klinische Bedeutung für die Weiterentwicklung der bildgebenden Verfahren in diesem Bereich. Insbesondere die MRT Diagnostik, als vergleichsweise neue Modalität, eröffnet durch stetig verbesserte Technik immer neue diagnostische Möglichkeiten. Im Rahmen von Originalarbeit I konnten wir zeigen, dass mit dem hochsensitiven Hepatozyten-spezifischen Kontrastmittel, durch Protokollmodifikation, eine qualitativ hochwertige optimierte Staginguntersuchung des gesamten Abdomens ermöglicht wird. Durch die vorgestellte Protokollmodifikation gelingt es die exzellente Leberbeurteilung der Gd-EOB MRT mit einer verbesserten Kontrastierung des restlichen Abdomens zu kombinieren und somit den Einsatz der Gd-EOB MRT im Staging des Abdomens verbessern. Durch die Optimierung des extrahepatischen Kontrasts und der gleichzeitig uneingeschränkten Leberbeurteilung ist der Einsatz der Gd-EOB MRT nicht länger auf die Beurteilung der Leber und des Oberbauchs beschränkt. Ergänzende Untersuchungen mittels KM-CT oder ECCM erscheinen daher nicht länger notwendig. Zur Optimierung der Differentialdiagnostik von hepatischen Tumoren konnten wir in Originalarbeit II zeigen, dass durch den Einsatz der Gd-EOB MRT die nicht-invasive Subtypen-Klassifizierung von HCA in der MRT verbessert werden kann. Insbesondere können durch die Analyse der Kontrastmittelaufnahme in der HBP die klinisch relevanten Subtypen des inflammatorischen und beta-Catenin-positiven HCA besser identifiziert werden. Da diese Subtypen häufiger zu Blutungen oder einer malignen Entartung neigen, kann die durch uns gezeigte, verbesserte nicht-invasive Diagnostik zu einer Vermeidung von Komplikationen durch eine frühzeitige Behandlung führen. Unsere Ergebnisse der Originalarbeit III zum Einsatz der PoSSe MRT im postoperativen Intervall nach hepatopankreatikobiliärer Resektion zeigen, dass durch ein verkürztes Untersuchungsprotokoll mit flüssigkeits-sensitiven T2w-Sequenzen die weitere Behandlung dieser Patienten adäquat geplant werden kann. Anhand der PoSSe MRT können behandlungsbedürftige Flüssigkeitskollektionen identifiziert und eine perkutane oder transgastrische Drainagenanlage suffizient indiziert werden. Auf Grund dieser Ergebnisse ist die Diagnostik mittels PoSSe MRT eine effektive Alternative ohne Strahlenexposition und Kontrastmittelapplikation für Patienten nach ausgedehnter Leber- oder Pankreaschirurgie. Die Gd-EOB MRT hat bereits einen hohen Stellenwert im Therapiemonitoring von Lebermetastasen unter Chemotherapie. Wir konnten in Originalarbeit IV zeigen, dass die in der klinischen Routine häufig ignorierten, hepatotoxischen Nebenwirkungen von Chemotherapeutika in der Gd-EOB MRT Untersuchung quantifiziert werden können und dass somit die anatomische Darstellung durch eine funktionelle Komponente ergänzt werden kann. Durch den Einsatz der Gd-EOB MRT in der Verlaufskontrolle von Lebermetastasen kann somit auf zusätzliche Leberfunktionsmessungen verzichtet werden. Durch die Identifizierung einer Chemotherapie-induzierten Hepatotoxizität kann ein potenziell tödliches postoperatives Leberversagen durch eine zu geringe Funktion der Restleber nach neoadjuvanter Therapie vermieden werden. Eine exakte Quantifizierung der hepatischen Tumorlast im Rahmen des Therapiemonitorings ist in der Gd-EOB MRT möglich, jedoch sehr zeitaufwändig, und hat deshalb bisher keinen Einzug in den klinischen Alltag gefunden. Das durch uns trainierte, und in Originalarbeit V vorgestellte, deep-learning basierte AI Modell erreichte eine hohe Genauigkeit in der 3D Segmentierung bzw. Quantifizierung von neuroendokrinen Lebermetastasen in der Gd-EOB MRT. Der vollautomatisierte Algorithmus konnte im Rahmen der hier vorgelegten Studie das Therapieansprechen vergleichbar mit der Genauigkeit einer multidisziplinären Tumorkonferenz bestimmen. Das Modell ist zu- dem durch seine Anwendung in der hepatobiliären Phase der Gd-EOB MRT nicht auf den Einsatz bei neuroendokrinen Lebermetastasen beschränkt und kann auch zur Quantifizierung von Lebermetastasen anderer Genese eingesetzt werden. Durch die Evaluation des AI Modells kann die Verlaufsbeurteilung von Lebermetastasen unter Chemotherapie verbessert werden. Das Modell ermöglicht neben einer exakten Beurteilung der Veränderungen des Tumorvolumens unter Therapie auch die Bestimmung der prädiktiven hepatischen Tumorlast. Zusammenfassend kann durch Protokollmodifikation (Originalarbeit I) eine optimierte Staginguntersuchung des gesamten Abdomens im Rahmen einer Gd-EOB MRT Untersuchung durchgeführt werden. Gleichzeitig ist es durch den Einsatz der Gd-EOB MRT möglich HCA in der hepatobiliären Phase in ihren histologischen Subtypen weiter zu differenzieren (Originalarbeit II). Ein verkürztes Untersuchungsprotokoll (PoSSe MRT) ermöglicht eine MRT Untersuchung im postoperativen Intervall nach ausgedehnten HPB Operationen, welche zur Detektion und Interventionsindikation von postoperativen Kollektionen geeignet ist (Originalarbeit III). Die Gd-EOB MRT kann zudem neben der optimalen Darstellung von hepatischen Tumoren die hepatotoxische Wirkung von Chemotherapeutika im Sinne einer funktionellen Diagnostik anzeigen (Originalarbeit IV). Durch den Einsatz von AI Techniken kann die hepatische Tumorlast in der Gd-EOB MRT vollständig automatisiert dreidimensional quantifiziert werden. Die automatische Quantifizierung ermöglicht eine exakte Darstellung des Tumorverhaltens unter Therapie und kann somit im klinischen Alltag eine Hilfestellung in der Beurteilung des Therapieansprechens leisten (Originalarbeit V).

In der vorliegenden Habilitationsschrift wurden die Inhalte von fünf wissenschaftlichen Arbeiten zu dem Thema 4D Fluss MRT bei kardiovaskulären Erkrankungen vorgestellt. Es erfolgte zunächst die Validierung der 4D Fluss MRT Methode und daraufhin deren Anwendung bei Patienten mit partieller Lungenvenenfehlmündung und Patienten mit univentrikulärer Anatomie. Des Weiteren wurde die Verbesserung der diagnostischen Möglichkeit bei komplexen Flussprofilen durch die 4D Fluss MRT Methode und die Vorhersage von postoperativen Flussgeschwindigkeiten und -profilen nach Aortenklappenersatz unter Verwendung von 4D Fluss MRT basierten numerischen Strömungsanalysen (CFD) beschrieben. Die 4D Fluss MRT Methode hat somit das Potenzial, gezielte klinische Anwendung bei kardiovaskulären Erkrankungen zu finden, die Diagnostik zu verbessern und dazu beizutragen, Therapien und somit Therapieergebnisse zu optimieren.

This thesis analyses the evolution of the sexual and gender-based violence prohibition norm at the International Criminal Court. Underpinned by social constructivist research on international norms, insights into the appropriate application of legal norms, as well as feminist institutionalist and legal perspectives, the evolution is identified as an outcome of a socialization process with the norm’s appropriate application. The case study, based on qualitative data analysis, embraces seven stages of this process, each accompanied by a triangulation inquiry. Connecting research on the evolution of norms in international relations with that on resistance practices against international courts, this analysis studies the constellation and agency of the involved actors, institutional and structural as well as socio-political factors. The findings of this study should contribute to the understanding and conceptualization of the evolution of international norms, specifically in the fields of human rights and gender justice from an interdisciplinary perspective, joining political, social and legal aspects through a feminist lens.

Title of the PhD-Thesis: From porcine skin samples in situ to three-dimensional human skin constructs in vitro. Studying skin with a focus on the 3R principles. Chapter 1 gives a general introduction to the importance of animal models, focusing on porcine models as well as on in vitro models in skin research. Chapter 2 presents a literature review of research on pigs as animal models for human skin in skin research and of in vitro models of skin research. Furthermore, the principle of the 3Rs is reviewed. Chapter 3 states the objectives and hypotheses of this thesis. Chapters 4 and 5 cover the two main publications for this thesis. Chapter 4 reports on the comparison between abdominal human skin and four different areas of pig skin (the ear, the flank, the back, and the caudal abdomen). The skin samples were examined by light microscope (LM), transmission electron microscope (TEM) and immunohistochemistry. In addition, skin permeability studies were performed. The results of this study show both the similarities and differences in histological and ultrastructural features. The epidermis of the examined regions in both pigs and humans, except for the stratum corneum, is of similar thickness. Although the number of corneocyte layers was not different in the two species, the human corneocyte layer was thicker than that of the pig. The dermal structure of humans and pigs is similar, the thickness of the human one is more similar to the one of the porcine flank and back region. The ear and caudal abdomen of the pig showed a thinner dermis when compared with those of humans. The epidermal-dermal thickness ratio of the porcine back, flank and abdomen was similar to that of humans. The dermo-epidermal length was not found to be different in humans and pigs. This is significant since the skin´s barrier function depends on this interface. The number of hair follicles and arrector pili muscles of the porcine abdominal and ear skin was different from that of the human skin. The number of sweat glands of the four areas of pig skin was not significantly different from that of the human skin. The number of blood vessels in the human dermis was significantly lower than in the pig dermis. Chapter 5 reports on the comparison between the two types of in-house skin constructs and human skin as examined by light and transmission electron microsopy. Data were analyzed by semi-quantitative and qualitative methods. The two types of skin constructs included a construct consisting of keratinocytes and fibroblasts only (type 1, KCFB) and another construct made of keratinocytes as well as fibroblasts and vascular endothelial cells (type 2, KCFB_EC). Both types of skin constructs showed all strata as known from human skin. When compared with the skin constructs without EC or with normal human skin, the skin constructs with endothelial cells were characterized by unorganized epidermal layers, significantly more mitotic cells in the stratum spinosum, more layers of the stratum granulosum and more keratohyaline granules. Chapter 6 discusses whether specific skin regions of domestic pigs were suitable for human skin replacement. According to the results reported in the first section, the back region, particularly of the German Landrace breed, had superior skin characteristics to those from the flank, the abdominal and the caudal ear regions. The dermal thickness of the back region was comparable to the thickness of human abdominal skin. It is possible that the caudal ear skin could be used as a model in studies of chemicals utilizing the trans-follicular route for their absorption. The second section addressed the morphology and ultrastructure, and the effect of endothelialization on epidermal differentiation in two types of skin constructs. The epidermis in both the KCFB and KCFB-EC skin models had a similar overall architecture and ultrastructure to native skin. When the KCFB-EC and KCFB models were compared, however, there were several differences. The KCFB-EC constructs featured more mitotic cells, a considerable epidermal differentiation, and a significantly more disorganized epidermal architecture. The data supported the hypothesis that VEGF promotes epidermal thickness and keratinocyte proliferation. VEGF was obtained from both culture medium and keratinocyte culture. Increased VEGF levels may play a crucial role in these issues. In addition, no vasculogenesis was observed in the fibroblast matrix of the KCFB-EC constructs. Due to a lack of interaction between endothelial cells and fibroblasts, endothelial cells failed to form capillaries. To build a stable dermis, fibroblasts and endothelial cells quantity must be optimized. Thus, the epidermis may be initiated by seeding keratinocytes on top of the optimal dermis.

Ziel dieser Arbeit ist die Zusammenstellung der Studien zur Ernährung der Katze bis 2020 in einer zusammenfassenden Übersichtsarbeit. Hierzu wurden zunächst 1164 Literaturquellen nach gezielten Kriterien systematisch ausgewählt, katalogisiert und entsprechenden zuvor festgelegten Themenfeldern zugeordnet. Es fanden sodann für diese Arbeit 491 Literaturquellen tatsächlich Berücksichtigung für die Auswertung. Katzen weisen als obligat carnivore Tierart verdauungs- und ernährungsphysiologische Besonderheiten auf. In der Ernährungsforschung nimmt die Beurteilung des Energiebedarfs seit Mitte der 1990er Jahre einen großen Stellenwert ein. Bei der Durchführung von Studien zum Energiebedarf ist es von großer Bedeutung, einen standardisierten Versuchsaufbau zu konzipieren, der eine einheitliche Methodik nutzt und beeinflussende Komponenten wie die Körperkonstitution, Geschlecht, Kastrationsstatus und Alter der Katzen berücksichtigt. Die Forschung zum Proteinbedarf beginnt schon etwa 10 Jahre früher in den Mittelpunkt des Interesses zu rücken. Die Katze kann direkt nach der Futteraufnahme die Aminosäuren zur Gluconeogenese nutzen. Sie ist auf der anderen Seite aber nur limitiert in der Lage, den katabolen Stoffwechsel der Enzyme im Proteinstoffwechsel an ein proteinarmes Futter anzupassen. Das dritte große Themenfeld in der Ernährung der Katze umfasst die Forschung zum Kohlenhydratstoffwechsel seit den 1980er Jahren. Der zunehmende Einsatz von Kohlenhydraten vor allem bei der Trockenfutterherstellung machte es notwendig, sich mit der Verdauung, Akzeptanz und möglichen Nebenwirkungen für die Fleischfresser zu befassen. So weist die Katze eine verringerte Aktivität der für die Verdauung von Kohlenhydraten verantwortlichen Enzyme auf. Interessanterweise ließ sich in mehreren Studien eine gute Verdaulichkeit vor allem von thermisch aufgeschlossenen Kohlenhydraten nachweisen. Allerdings lässt die Akzeptanz eines Futter mit mehr als 30 % Kohlenhydratanteil deutlich nach. Kontroverse Diskussionen gibt es im Hinblick auf den Einfluss von der Trockenfuttergabe auf ernährungsbedingte Erkrankungen. Hier liegt der Fokus bei der Erforschung der Entstehung von Übergewicht und Diabetes mellitus. Der Zusammenhang zwischen dem Phosphatgehalt im Futter und der Ausbildung einer CNE bei bisher gesunden Katzen bzw. der Progression der Erkrankung bei erkrankten Katzen ist aktuell im Mittelpunkt der Forschung. Auch stieg das Interesse in den 2000er Jahren bei den Studien zu anderen Mineralstoffen in Futtermitteln, da hier ein direkter Bezug zu ernährungsbedingten Krankheiten wie der FLUTD und der CNE hergestellt werden konnte. Recht übersichtlich sind die Studien in der Rubrik Fette und Vitamine, die vor allem in den 1980er und 1990er Jahren durchgeführt wurden. Hier scheinen die Ergebnisse wenig Anlass für weitere Studiendesigns zu liefern. In der Gesamtheit stellen die hier zusammengetragenen Studienergebnisse die Schwierigkeit verbindlicher und langfristig geltender Aussagen und Empfehlungen zur optimalen Ernährung der Katze dar. So werden die Empfehlungen internationaler Vereinigungen für die einzelnen Nährstoffe immer wieder hinterfragt. Für zukünftige Studien sollte der Fokus auf der Erforschung und vor allem der Prävention von ernährungsbedingten Erkrankungen liegen. Für eine bessere Vergleichbarkeit der Studienergebnisse wäre hierbei eine Standardisierung des Studiendesigns erstrebenswert. Bei aller Sorgfalt in der Erarbeitung eines idealen Fütterungsregimes der Hauskatze wird als individueller und schwer kalkulierbarer Faktor immer der Tierhalter stehen, der in der Lage sein muss, die entsprechenden Empfehlungen bestmöglich umzusetzen.

Thermophilic Campylobacter spp. are zoonotic bacteria leading to the most often reported gastroenteritis in the European Union. Campylobacter jejuni and Campylobacter coli are the major species relevant for human campylobacteriosis, which manifests with watery or bloody diarrhea, abdominal cramps, fever and in few cases leads to autoimmune sequelae, such as reactive arthritis, irritable bowel disease and Guillain-Barré syndrome. Even though the pathogens are fastidious in vitro and only grow at reduced oxygen levels, they are very successful in colonizing different warm-blooded hosts and in quickly spreading within a chicken flock. This PhD theses was focused on genomic diversity of C. jejuni and C. coli and the underlying mechanisms, in particular, natural transformation, which is the capacity to take up free DNA from the environment and adapt to changing conditions. We identified strains with ambiguous results in species differentiation by real-time PCR targeting genes, usually distinct for C. coli and C. jejuni. Using next generation sequencing and k-mer analysis the strains were identified as C. coli, harboring a substantial amount of recombined C. jejuni sequences, leading to gene variants. Interestingly, these so-called hybrid strains shared a common set of genes with C. jejuni sequence introgression, which may have a potential role in stress defense. Since the hybrid strains were preferentially isolated from egg shells, which is a dry and harmful environment for thermophilic Campylobacter spp., this may hint at selection for strains which survived harsh environmental conditions. It also demonstrated that Campylobacter is able to undergo extensive genetic exchange. The question arose, under which conditions the pathogen acquires genetic material by natural transformation, leading to the introduction of such an amount of new genetic material. Factors regulating natural transformation and competence development are only poorly understood in C. jejuni. Therefore, we developed a single cell-based uptake assay to monitor competence development. As a fresh field isolate we used C. jejuni strain BfR-CA-14430 which had recently been isolated from chicken meat and belongs to clonal complex 21 (ST44), which is also commonly found in human isolates. For better comparability this strain was distributed for common use in the PAC-CAMPY consortium. Since no sequence data was available we sequenced this strain using short-read Illumina and single molecule real-time (SMRT) long-read sequence analysis. BfR-CA-14430 had a genome size of 1.6 Mb and harbored a 41 kb plasmid. For visualization of DNA uptake, we covalently labelled C. jejuni genomic DNA with a fluorophore and added this labelled DNA to C. jejuni cells under different growth conditions. The results obtained by the single cell assay correlated well with the results obtained by a classical assay approach based on the transformation and subsequent selection for a resistance marker. This showed that the assay is a powerful tool to analyze competence development in C. jejuni. Increase from pH 6.5 to 7.5 resulted in a higher fraction of competent cells. Below pH 5 neither competence development nor DNA uptake was observed. Furthermore, aerobic conditions abolished competence development but not DNA uptake in already competent C. jejuni. These findings suggested a strong regulation of competence development in C. jejuni. We further showed that competence development in C. jejuni did not depend on growth temperatures or carbon dioxide concentrations. Since C. jejuni often resides in the slightly alkaline intestine of poultry, the results implicate extensive genetic exchange in the host. This might be beneficial to switch hosts and/or to survive in the environment. In a cooperation study, the single cell assay was used to check the effect of an immune-stimulative substance, curcumin, which was suggested as a potential treatment option for campylobacteriosis, on natural transformation. The DNA uptake assay did not identify either stimulating or inhibiting effects of curcumin on natural transformation in C. jejuni, which corroborates its application during campylobacteriosis without triggering the adaptive potential of the pathogen. In conclusion, extensive genetic exchange occurs in Campylobacter, potentially enlarging the adaptive potential of the food-borne pathogen. This might support the pathogen as successful colonizer and survivor. Besides, high genetic plasticity may hinder correct diagnostics and has to be taken into account for continuous monitoring of Campylobacter variants. It remains important to study natural transformation in detail in order to reduce the adaptability of thermophilic Campylobacter spp. in the future.

A remarkable discovery made in rodents three decades ago demonstrated that the brain reactivates previous experience during sleep and wakeful rest. This phenomenon, since known as replay, has been implicated in a variety of cognitive functions, ranging from spatial navigation and episodic memory consolidation to planning and decision-making. At the same time, research in machine learning (ML) has found that experience replay can substantially improve the performance of artificial agents. Together, these observations have spawned the idea that replay supports behavior by retrieving information from abstract internal representations of the environment. How the interplay between replay and internal task representations supports learning and decision-making in humans is still not well understood. In addition, investigating replay in humans is challenging because replay is fast, sequential, and occurs throughout the brain, but current non-invasive neuroimaging methods offer either sufficient temporal or spatial resolution, but not both. This dissertation consists of three publications that offer a theoretical and empirical perspective on the role of replay in learning and decision-making as well as methodological advances for the study of replay in humans using functional magnetic resonance imaging (fMRI). In Paper I, we provide a review of the recent computational and neuroscientific literature on replay and elucidate how replay can improve learning and decision-making in both biological and artificial agents. We identified five key computational functions of replay which include faster and data efficient learning, less forgetting, the reorganization and augmentation of experiences, planning, and generalization. We also discussed the benefits of reactivating abstract internal representations instead of recapitulating veridical experiences, and explored the idea that replay could be involved in learning which representation is useful for a given task. In Paper II, we developed and experimentally validated multivariate analysis methods for fMRI that allow studying the sequentiality and speed of fast-paced neural event sequences, like replay, with anatomical precision in humans. The results showed that probabilistic fMRI pattern classifiers make it possible to detect the sequential order of neural image representations at speeds of up to 32 milliseconds between sequence items. Finally, applying these methods to fMRI data from awake resting-state scans, we could differentiate fast from slow neural sequences that occurred at random time points and found evidence for sequential replay of task-related stimulus sequences during post-task rest. In Paper III, we investigated how humans form predictive internal representations of the statistical relationships between task stimuli and if the brain reactivates sequences from these internal representations during short pauses from ongoing behavior. The results showed that humans learned the higher-order relationships between consecutively presented images in the form of a predictive cognitive map that represents each item in terms of the subsequent items that follow from it. Applying the fMRI methods developed in Paper II to neural data during short pauses interleaved with task performance, we found that participants reactivated upcoming stimulus sequences that were most likely given this predictive internal representation. In summary, this dissertation makes three major contributions. First, linking findings about replay in the neuroscience and ML literature spurs new ideas how replay can support learning and decision-making in both biological and artificial agents. Second, novel methods to characterize the speed and sequentiality of replay with spatial specificity using fMRI have the potential to foster future insights into the role of replay in the human brain. Third, studying how replay interacts with internal representations opens avenues to further understand how the reactivation of experience supports adaptive behavior in machines and humans.

Magnetic resonance imaging (MRI) remains one of the most essential clinical tools for the early detection, diagnosis, and therapeutic management of multiple sclerosis (MS). Until now it has been important to detect and assess neuroinflammatory disease as well as to assess the response to prescribed disease modifying treatments (DMT). The gold standard to detect new relapses and new inflammatory episodes in MS is the detection of contrast-enhanced lesions with gadolinium-based contrast agents. Concerns regarding potential long-term deposition of these agents in the brain are advocating a paradigm shift towards new contrast-free MRI methods and biomarkers. Ultrahigh field (UHF) strengths have been instrumental to increase the level of detail and spatial resolution in brain MR images of MS patients and hence to uncover novel markers such as the central vein sign that are relevant to the MS pathology. An observation that we made in MS patients as well as in its animal model, the experimental autoimmune encephalomyelitis (EAE), is that brain ventricle size fluctuations play an important role early during the pathogenesis of the disease. Fluctuations in ventricle size appeared to follow the relapsing-remitting form of disease progression. In MS patients, we observed a high degree of cross-correlation between the timing of abnormal ventricle fluctuations and timing of changes in other clinical and MRI parameters. These cross-correlations seemed to be as strong as those achieved between contrast-enhanced MRI and the other parameters, indicating a similar level of diagnostic value between ventricle size and contrast-enhanced MRI in MS. MRI has also been instrumental to initiate treatment as early as possible in MS and to adjust treatment routines according to disease progression. Beyond this, MR methods may also be used to study the distribution of DMTs during pathology. Using MR spectroscopy (MRS) we recently detected teriflunomide in the brains of mice during EAE. Teriflunomide is used in relapsing-remitting MS patients as a DMT to prevent relapses. We used MRS to study teriflunomide levels during different disease stages of the EAE, compared MRS with an analytical method as reference and showed a correlation between both methods. Our results indicate that MRS could be used in the future to quantify drugs such as teriflunomide non-invasively in MS patients. Unfortunately, the significance of fluorine (19F) MRI to detect, follow and quantify DMTs in patients has not yet been sufficiently recognized nor has its need been appreciated, mostly because of its hurdles with respect to sensitivity barriers. While we used MRS to detect teriflunomide in the EAE in vivo, limits in signal sensitivity currently prohibit the detection of such drugs with MRI or single-voxel MRS. Novel methods and technologies that enhance sensitivity and signal-to-noise ratio (SNR) will be necessary to surmount this hurdle. Amongst the methods that we implement to increase SNR for 19F MRI, cryogenically cooled radio frequency (RF) coils significantly reduce thermal noise by the hardware, thereby increasing SNR by over an order of magnitude beyond that of a room temperature RF coil of similar size. While it is still debatable whether this technology can be used to improve SNR in the clinical setting, other methods of increasing SNR can certainly be valuable for implementation in the clinic. These include higher magnetic fields and methods to accelerate data acquisition such as compressed sensing. These will all be key to achieve the goal necessary to increase SNR and monitor drugs in vivo with MR methods. Future directions: Apart from increasing the sensitivity of the MR method, it will be necessary to focus on the signal source in the future while gauging MRI as a method to study the distribution of drug treatments. The design and synthesis of molecular labels and imaging probes will be an important domain in future MRI research. Incorporating MR reporter function to lead compounds should be a necessary added dimension when studying new compounds during drug discovery. Collaborations between academia and industry will be necessary to broaden this field of theranostics.

Rydberg atoms are the “giants” in the world of atomic physics. Their highly excited valence electron gives them remarkable properties, such as a long lifetime, large dipole moments and great sensitivity to external fields rendering them ideal tools for the study of quantum effects and quantum technology applications. Quantum technologies promise to outperform their classical counterparts in terms of speed, security, accuracy and performance while presenting us with new challenges. This thesis explores different applications of Rydberg atoms for quantum technologies from a quantum control perspective with a special focus on quantum measurements.

Many quantum technologies require the fast and accurate engineering of quantum states to achieve peak performance and avoid decoherence. I tackle this requirement by employing quantum optimal control theory (OCT) and demonstrate fast and accurate navigation in the high-dimensional Stark manifold of rubidium Rydberg atoms. This is illustrated by means of two examples: the circularisation of Rydberg atoms and the preparation of a Schrödinger-cat-like state which promises quantum sensing of electric fields at the fundamental limit using alkali atoms.

While Rydberg physics has focused for a long time on alkali atoms, it is worth to extend the study to alkaline-earth atoms, as their second valence electron promises new opportunities for quantum technology. However, modelling alkaline-earth atoms is challenging due to electronic interactions. I therefore develop an improved single-active-electron model and optimise the parameters to maximise the agreement with spectroscopic data. This enables OCT applications of strontium which require a precise model for the quantum system under consideration.

Fast protocols are an important tool to avoid decoherence. However, quantum technologies rely on accessing the system for information processing and read-out. The study of open quantum systems is thus crucial for realising quantum technology in presence of decoherence. I therefore propose a quantum simulator for open quantum systems which enables the systematic study of dissipation, memory effects and their interplay for quantum control. The simulator is based on frequent measurements of a system by a meter which can be realised, for instance, by a photonic mode of a cavity and a Rydberg atom, respectively.

The strong interaction of composite systems involving Rydberg atoms lends itself not only for quantum simulation but also for spectroscopy. Many standard detection methods for quantum objects are based on their destruction, e.g. by absorption or ionisation. Förster resonance energy transfer (FRET), on the other hand, is a popular spectroscopic tool and promising candidate for the non-destructive detection of polar molecules. The large size of Rydberg atoms, however, suggests a breakdown of the commonly employed dipole-dipole approximation. To enable the study of FRET, I simulate the collision between a Rydberg atom and a polar molecule considering dipole-dipole, -quadrupole and -octupole interactions. The computed scattering cross-sections allow for studying of the multipolar character of FRET and its spectroscopic potential.

In den letzten zwei Dekaden haben sich im Feld der Spondyloarthritiden wichtige Neuerungen ergeben. Vordergründig sind das Konzept der axialen Spondyloarthritis als Kontinuum mit zwei Untergruppen – der radiographischen axialen Spondyloarthritis und der nicht-röntgenologischen axialen Spondyloarthritis, die Diagnostik der Erkrankung unter Einbezug der MRT zur Erkennung der Frühformen der Erkrankung sowie direkten Visualisierung entzündlicher Prozesse im Bereich der Wirbelsäule sowie der SIG, die Implementation neuer Klassifikationskriterien sowie die Zulassung diverser hocheffektiver Therapien zu nennen. Nichtsdestotrotz bleiben weitere wichtige Fragen bestehen. So ist insbesondere die Ätiologie und Pathogenese der axSpA nicht ausreichend verstanden und somit stehen lediglich effektive Behandlungsansätze, jedoch weiterhin keine Heilungsmöglichkeiten dieser chronischen immunvermittelten Erkrankung zur Verfügung stehen. Ein wichtiger Schritt zu einem besseren Verständnis der Erkrankung könnte in der Entdeckung des Zusammenspiels des gastro-intestinalen Microbioms mit den Spondyloarthritiden bestehen. [135, 136] Dessen Einfluss auf Krankheitsentstehung und Krankheitsaktivität muss jedoch noch weiter erforscht werden, um hieraus möglichen Nutzen ziehen zu können. Auch konnte die Diagnoseverzögerung deutlich verkürzt werden, jedoch ist diese weiterhin mit durchschnittlich 5,7 Jahren in Deutschland [41] inakzeptabel lange und der Fokus zur Frühdiagnose muss beibehalten und nach neuen Möglichkeiten - auch unter Einbezug digitaler Ansätze – gesucht werden. Darüber hinaus erreichen trotz der Zulassung von bDMARDs als neue Therapieoptionen im klinischen Alltag weiterhin weniger als die Hälfte der axSpA Patienten den angestrebten Zustand einer inaktiven Erkrankung. [137, 138] Dies muss als ein klares Signal verstanden werden einerseits die zur Verfügung stehenden Therapien konsequenter einzusetzen und andererseits nach weiteren Therapieoptionen sowie komplementären Maßnahmen zu forschen. Da auf Grund der zum Teil erst kürzlich erfolgten Zulassungen diverser bDMARDs für das gesamte Spektrum der axSpA Langzeiterfahrungen zum Einsatz dieser Medikamente in der Patientengruppe mit axSpA fehlen, ist es von hoher Bedeutung Erfahrungen zu Sicherheit und Wirksamkeit dieser Therapien bei Patienten 84 mit axSpA im „echten Leben“ anhand von Registerdaten und Beobachtungsstudien zu sammeln. Um einen Leitfaden für die optimale Versorgung von axSpA Patienten zu haben stellen die kürzlich veröffentlichten Qualitätsstandards der ASAS [67] einen Meilenstein dar. Jedoch müssen Wege identifiziert werden, wie die hier empfohlenen Maßnahmen auch im Rahmen der klinischen Routine unter dem wirtschaftlichen Druck sowie in Anbetracht der aktuellen Versorgungssituation erreicht werden können. Im Rahmen dieser Habilitationsschrift wurde der aktuelle Stand zu den Themen der Diagnostik, Therapie und Verlaufsbeurteilung bei der axialen Spondyloarthritis erörtert, die eigenen Arbeiten zu dem Thema vorgestellt und deren möglicher Einfluss auf die Versorgungssituation von Betroffenen diskutiert. Darüber hinaus wurden weiterhin bestehende Fragen zur axialen Spondyloarthritis definiert, welche im Rahmen wissenschaftlicher Projekte in der Zukunft bearbeitet werden sollten.

This dissertation examines the introduction of the technologies of motion pictures and recorded sound in Argentina, Chile, and Uruguay and analyzes the changes they triggered in communication and cultural production. It reconstructs the lives and careers of a group of immigrant men who sold, distributed, and produced movies and records for the urban markets of these three countries, shaping the emergence of new media and the integration of the region into a global entertainment market. This dissertation poses the question of what impact the positions of Argentina, Chile, and Uruguay in the global economy had on the changes triggered by the introduction of motion picture and recorded sound technologies. It argues that cities in these three countries became part of a global entertainment market between the 1890s and 1920s in a particular way, which had important implications for cultural production and communication. Unlike in the United States and Europe, where production was the most dynamic sphere and producers the most powerful actors, the growth of the sphere of consumption drove the consolidation of distribution networks and the production of films and records in the case of the countries under examination in this study. Through advertisement and based on knowledge about the users’ expectations and demands, retailers shaped the appropriations of the new technologies. Entrepreneurs followed a strategy of vertical integration by moving from commercialization to distribution, establishing agreements with European and US based companies for the rights of their products in the region, further competing against each other for the bigger share. This had consequences for production and for the discourses that these media spread and contributed to shape alleged national cultural expressions, since producers favored certain genres and contents in which they could offer a distinctive feature based on local cultural references.

BHLHE40 ist ein Transkriptionsfaktor aus der Familie der basic helix-loop-helix Proteine, der hauptsächlich als Transkriptionsrepressor fungiert. Die repressive Wirkung wird meist via direkter DNA-Bindung oder indirekt, über Protein-Protein-Interaktion mit anderen Transkriptionsfaktoren, vermittelt. BHLHE40 ist involviert in die Steuerung der Adipogenese im Fettgewebe. Darüber hinaus lieferten Voruntersuchungen zu der vorliegenden Arbeit Hinweise darauf, dass BHLHE40, über die Beeinflussung von PPARα- und ChREBP-Zielgenen, an der Regulation des Energiestoffwechsels in der Leber beteiligt ist. Diese Arbeit sollte dazu beitragen, die Rolle von BHLHE40 während der Adipozytendifferenzierung noch besser zu verstehen, sowie potenzielle neue Funktionen von BHLHE40 im Energiemetabolismus der Leber aufzudecken. In diesem Zusammenhang wurde zusätzlich mittels Chromatin-Immunpräzipitation nach neuen genomischen BHLHE40-Bindungsstellen in der Leber gesucht. Zunächst konnten die Ergebnisse einer anderen Arbeitsgruppe bestätigt werden, dass eine Bhlhe40-Überexpression in 3T3-L1 Zellen zu einer Inhibition der Adipogenese führt. Diese hemmende Wirkung scheint allerdings nicht, wie vorgeschlagen, über eine direkte Repression der Pparγ2-Promotoraktivität vermittelt zu werden. Vielmehr deuten Ergebnisse dieser Arbeit darauf hin, dass BHLHE40 die Differenzierungskaskade upstream von PPAR2 hemmt. Weiterhin konnte gezeigt werden, dass ein Bhlhe40-Knockdown den gegenteiligen Effekt auf 3T3-L1 Zellen hat und die Adipozytendifferenzierung fördert. Anhand von Bhlhe40-Knockdown und -Überexpression in primären murinen Hepatozyten, konnte im zweiten Teil dieser Arbeit festgestellt werden, dass BHLHE40 die Expression bestimmter PPARα- und ChREBP-Zielgene fördert. Insbesondere die Expression von Hmgcs2, limitierendes Enzym in der Ketogenese, wird durch Bhlhe40-Knockdown und Bhlhe40-Überexpression signifikant reguliert. Zusammen mit der Tatsache, dass BHLHE40 unter Fütterung in der Leber hochreguliert wird, deutet dieses Ergebnis darauf hin, dass BHLHE40 an der Entstehung der diabetischen Ketose unter Hyperglykämie beteiligt ist. Zuletzt wurden mittels BHLHE40-spezifischer Chromatin-Immunpräzipitation in Leberproben von gefütterten, männlichen C57BL/6J Mäusen neue genomische BHLHE40-Bindungsstellen in der Nähe der Gene Klf10 und Dgat2 detektiert.

In dieser Studie wurde der Einfluss,den verschiedene Schweregrade von Geburtshilfen bei Kühen auf die folgende Laktation hatten betrachtet. Es wurden retrospektiv Daten zu 261 Geburten, an denen eine tierärztliche Geburtshilfe geleistet worden war, in drei Gruppen eingeteilt: mittlere Geburtshilfe (MG), schwere Geburtshilfe (SG) und Kaiserschnitt (KS). Zu jeder Schwergeburt wurde ein Kontrolltier ausgewählt, das ohne tierärztliche Hilfe im selben Zeitraum gekalbt hatte und im selben Alter, in derselben Laktation war und derselben Rasse angehörte. Studien und Kontrolltiere wurden hinsichtlich Milchleistung, Milchinhaltsstoffe, Fruchtbarkeit und Abgangsraten von Kuh und Kalb untersucht. MG hatte nur geringe Auswirkungen auf die Milchleistung, Fruchtbarkeit und die Abgangsrate der Kühe. Verglichen mit den Kontrolltieren gingen mehr SG (28.1 vs. 25.8%) und KS (30.3 vs. 15.8%) ab. Bis zum 200. Laktationstag waren weniger Tiere tragend in der SG Gruppe (48.3 vs. 61.8%) und in der KS Gruppe (48.7 vs. 69.7%). Der Unterschied war nur für die KS Tiere signifikant. Die SG zeigte keinen Einfluss auf die Milchleistung, während die KS tiere eine signifikant niedrigere Milchleistung in den ersten 5 Kontrollmonaten als ihre Kontrolltiere aufwiesen. Im Vergleich zu der Kontrolltieren steigen die Kosten mit der Schwere der Geburtshilfe an (MG 58.86, SG 130.51, KS 236.61 / Tier).

The overall objective of the present work is the translation of advanced qMRI techniques from the research environment into the field of clinical neuroimaging. In this context, qMRI is defined as the application of absolute quantitative measures that are extracted from in vivo MRI data. These can be used to describe biophysical characteristics and processes and thereby enhance the diagnostic power of qualitative, “weighted” imaging that is primarily used in the clinical setting. The feasibility, usefulness, and limitations of five qMRI techniques were investigated in different CNS pathologies (brain tumours, ischaemic stroke, migraine, brain/skull malformations) and in the description of normal brain maturation in infants and young children. The translation of new imaging methods from “bench to bedside” involves several steps, and the presented studies are located at different stages in this process.

Studies 1 and 2 are examples of a relatively early stage. At the time of publication, pH-weighted APT imaging had been tested preclinically and in smaller cohorts of patients, but not in acute stroke, where anaerobic glycolysis and tissue acidosis is highly prevalent. In study 1, it was postulated that APT imaging could be a novel approach to demonstrate oligaemia in hyperacute stroke, allowing a more detailed description of tissue at risk. For acceleration purposes, sequence parameters were optimised by using computer simulations and subsequently validated in healthy subjects. Ten acute stroke patients were included (7 < 4 hours, 3 < 24 hours after symptom onset). As expected, the APT effect was significantly decreased in ischaemic regions compared to normal white matter (p=0.03) and APT values tended to be lower in the final infarct volume (p=0.10). In study 2, APT imaging was moved to a different pathology, also characterised by hypoperfusion, tissue hypoxia, and anaerobic glycolysis. Here, the metabolic changes during the migraine aura of a patient with FHM were investigated for the first time using APT imaging. The patient developed clear tissue acidosis and blood flow disturbances in the absence of ischaemia in the affected cerebral hemisphere, possibly caused by CSD, i.e. the state of neuronal inhibition that is supposed to be the pathophysiological basis of migraine aura. The studies were not designed to provide a statistical conclusion, but to identify technical strengths and weaknesses of this imaging technique.

Study 6 also represents an early phase of clinical translation. Here, a new postprocessing approach was developed to achieve absolute metrics for the measurement of dynamic processes on CINE MRI, a time-resolved method to visualise moving structures in vivo, e.g. in cardiac, bowel, or foetal imaging. Usually movement is evaluated qualitatively and to date objective quantitative approaches are missing. In this study, a measuring method (voxel intensity distribution method, VIDM) for subtle movements was developed and applied in 27 children with Chiari and other brain/skull malformations, where cerebellar tissue herniates dynamically through the foramen magnum following CSF pulsatility. The degree of movement was compared using VIDM and visually derived, clinically accepted linear measurements on CINE sequences. In 85% of the patients, VIDM showed significantly more cerebellar displacement (p=0.002) compared to simple visual assessments, although this did not correlate with the clinical outcome parameters (hydrocephalus or syringomyelia; Pearson’s correlation coefficient -0.28; p=0.16). It is suggested that VIDM might be a valuable tool to detect and measure subtle dynamic processes in the CNS, but extracranial applications are also very likely.

Study 3 and 7 represent validation studies of methods that have been presented in clinical data before. In study 3, 2HG MRS was used in 35 patients suspected for cerebral gliomas to determine the IDH mutational status that today is an integral part of the WHO brain tumour classification system. For this study, a dedicated MRS sequence was used and the routine imaging protocol was extended by only 6 min. The sensitivity/specificity for determining the IDH mutational status was 89.5% and 81.3%, respectively. It could be concluded that 2HG MRS is an easily applicable supplement to standard imaging protocols that allows presurgical diagnostics and opens up for more detailed assessment during treatment.

In study 7, T1 maps were generated from clinical MRI data using the MP2RAGE sequence, a technique extensively applied in neuroscience, but little in the clinical setting. The technical parameters were adapted to find a balance between short acquisition times, high signal-to-noise, and reliable T1 values to quantify myelin maturation in 94 children up to the age of 6 years. The assessment of adequate myelination is a central part of paediatric imaging diagnostics, but is to date done by evaluating images qualitatively. The aim was to validate the MP2RAGE-based T1 mapping technique for the assessment of normal myelination, and data were compared to those of children with various CNS pathologies. Additionally, the diagnostic power of the MP2RAGE was pointed out for the qualitative assessment of regular myelination and brain pathologies. The purpose of study 4 and 5 was to improve the diagnostic confidence of perfusion-weighted DCE maps. DCE is a well-established technique outside the CNS, but is used less in neuroimaging due to a number of technical issues. Here, postprocessing was addressed with the aim to reduce noise in the resultant parameter maps. Two curve-fitting methods, the Levenberg-Marquardt (LM) algorithm and a Baysian method (BM), were compared in digital phantoms and in 42 glioma patients applying two compartmental models (extended Toft’s, ETM, and 2-compartment- exchange model, 2CXM). The image quality was assessed with regard to tumour discrimination and overall impression of the images. Moreover, the diagnostic performance to differentiate high-grade from low-grade gliomas was investigated. The image quality of parameter maps generated by BM was significantly improved compared to LM (p<0.001), and the 2CXM- based maps were higher rated, regardless of the fitting method. The diagnostic performance to differentiate tumour grades was excellent for Ktrans and Vp (p<0.001). This was not affected by the fitting method for the leakage parameter Ktrans, whereas Vp was improved when using BM. These studies suggest that using BM to derive perfusion parameters from DCE data are superior to LM, hopefully leading to higher diagnostic confidence and acceptance in the clinical community. Clinical imaging diagnostics benefits without doubt from the integration of quantitative information gained by qMRI, thereby increasing reproducibility and reliability and enabling the objective comparison to normative and patient databases. Each step of the clinical translation process is essential to show opportunities, identify areas of optimisation, and to reveal challenges and limitations. After further development APT imaging is today available on standard MRI platforms, and BM-based curve fitting of perfusion data has been implemented in postprocessing software programmes. T1 maps of normal myelination in children are made publicly available and may be a first step towards an automated tool to detect myelination disorders more efficiently.