Antioxidantien als Strategie zur Optimierung der Kryokonservierung von Stammzellen für das Tissue Engineering

Kontrolliertes Einfrieren in den Temperaturbereich zwischen – 80 °C und – 196 °C erlaubt es Zellen, bei gleichzeitigem Erhalt ihrer Vitalität nach dem Auftauprozess, langfristig zu lagern. Durch die Verwendung von Antioxidantien sollte in der vorliegenden Arbeit eine Steigerung der Rekultivierbarkeit von mesenchymalen Stammzellen nach der Kryokonservierung erzielt werden. Der Zusatz von 100 μM α–Tocopherol steigerte die Rekultivierungseffzienz der Stammzellen um 117,5 % gegenüber der Kontrolle ohne Antioxidans. Darüber hinaus konnte gezeigt werden, dass eine Reduzierung der DMSO-Konzentration möglich ist, da Versuche mit 200 μM α–Tocopherol und 2,5 % bzw. 5 % DMSO vergleichbare Resultate von ca. 164 % bzw. 170 % Rekultivierbarkeit erzielten.EXC/62/

Aktueller Stand der tierärztlichen Forschung zu privater Tierhaltung mittels Online-Befragungen

Aktueller Stand der tierärztlichen Forschung zu privater Tierhaltung mittels Online-Befragungen In vielen Forschungsbereichen werden bereits seit zwei Jahrzehnten zunehmend Online-Befragungen zur Datenerhebung eingesetzt sowie die Methodik als sol-che beforscht. Ziel dieser Arbeit war es, einen Überblick darüber zu geben, wie in Fachzeitschriften veröffentlichte Online-Befragungen in der tiermedizinischen Forschung zur privaten Tierhaltung durchgeführt werden. In der vorliegenden Arbeit wurden 90 Publikationen zu 82 Befragungen aus dem Publikationszeitraum 2007–2016 untersucht. Es wurde bei der Datenerfassung, ebenso wie bei der Auswertung, zwischen der Publikations- und der Befragungs-Ebene unterschieden. Wie sich anhand der Ergebnisse zeigt, nimmt die tiermedizinische Forschung zur privaten Tierhaltung mit Hilfe von Online-Befragungen zu. Vorrangig beforscht wurde Tierverhalten, am wenigsten beforscht wurden das Wissen und die Sach-kunde der Teilnehmer. Die meisten Befragungen richteten sich an Tierhalter und zielten auf Hunde, Pferde und Katzen ab. Die meisten Publikationen stammen aus Nordamerika, Europa und Australien. Ebenso fanden die meisten Befragun-gen in diesen geografischen Bereichen statt. Wie sich bei der Auswertung herausgestellt hat, gibt es bei Online-Befragungen einige Schwächen, die regelmäßig anzutreffen sind. - Zunächst gibt es Probleme bei der Studienplanung. Zu wenig Fragebögen werden vor ihrer Verwendung einem Pretest unterzogen (31 von 82) und es konnte festgestellt werden, dass methodische Fehler, wie zu geringe Stichprobengrößen oder zu ungenau gestellte Fragen, auftreten. - Des Weiteren werden die aus Fragebögen erhaltenen Daten nicht ausrei-chend auf ihre Qualität geprüft. Für 28 Befragungen fand überhaupt keine Datenbereinigung statt. - Zuletzt sind Methodik und Diskussion der Online-Befragungen in den Publikationen in vielen Fällen nicht so dokumentiert, wie es in der Litera-tur und Autorenrichtlinien gefordert wird. Der Anteil fehlender Angaben in der Methodikbeschreibung beträgt bis zu 89 % und für 21 % der Befra-gungen fand sich keine Diskussion der Limitierungen der Studienergeb-nisse aufgrund der verwendeten Methodik. Dies weist auch auf unzu-reichende Schulung der Reviewer hin. Befragungen scheinen unter Berücksichtigung der guten wissenschaftlichen Praxis eine geeignete Methode zu sein, um Daten über Tierhaltung, Tierschutz, Tierverhalten, Mensch-Tier-Interaktion und Wissen bei privater Tierhaltung zu erhalten. Da die Verbreitung von Internet, wie sich in der Literatur zeigt, in den letzten Jahren rapide zugenommen hat, können diese auch als Online-Befragung gut eingesetzt werden. Es wird aber empfohlen, Forschungen, die diese Methodik verwenden, entspre-chend akkurater zu planen und durchzuführen sowie deren Publikationen genau-er und mit allen zugehörigen methodischen und limitierenden Aspekten zu ver-fassen. Hinweise und Richtlinien über die korrekte Vorgehensweise können, wie die Literaturübersicht dieser Arbeit zeigt, der Fachliteratur entnommen werden. Auch Reviewer sollten genauer auf die beschriebene Methodik und Diskussion von möglichen Limitierungen achten.Current status of veterinarian research on private husbandry using online surveys For the past two decades, online surveys have been used for data collection in many areas of research, and the method itself has also been studied. This study aims to give an overview of how online surveys are used in the veterinary sci-ences, specifically in journal articles on private husbandry. For this thesis, 90 publications on 82 online surveys, published between 2007 and 2016, have been investigated. For data collection as well as for the analysis itself, a distinction has been drawn between the level of publication and survey. The results show that there is an increase in veterinarian research on private husbandry using online surveys. The most commonly studied subject is animal behaviour, while the knowledge and expertise of participants is studied the least. Most surveys were aimed at pet owners and inquired after dogs, horses and cats. Most articles are by authors based in North America, Europe, and Austral-ia. Most surveys were also carried out in those geographical areas. The analysis has revealed that studies relying on online surveys frequently dis-play the following deficiencies. - Firstly, the study design is often inadequate. Too few questionnaires are pretested before being used (31 of 82) and there are methodological mis-takes such as undersized sample sizes or imprecise wording of ques-tions. - In addition, the quality of data obtained from questionnaires is not ade-quately evaluated. For 28 surveys no data cleansing took place at all. - Finally, in the publications themselves, method and discussion of online surveys are often not documented according to the literature and author guidelines. The percentage of missing data in the method description is up to 89 % and in 21 % of the surveys, no discussion of the limitations of survey results due to the method used could be found. This suggests also that reviewers are insufficiently trained. Surveys making use of good scientific practice seem to be an appropriate meth-od for obtaining data about animal housing, animal welfare, animal behaviour, human-animal interactions, and knowledge about private husbandry. As the in-ternet has become widely used in recent years (this is obvious from the litera-ture), online surveys are also an effective tool. However, I recommend that research making use of this method should be planned and conducted more accurately and for the resulting publications to be written more precisely, with reference to all related methodological and limiting aspects. As the literature review for this thesis shows, advice and guidelines for the correct approach are readily available. Reviewers should also pay more at-tention to how methodology is described, and if there is an adequate discussion of possible limitations

Cryopreservation of cells using defined serum-free cryoprotective agents

For regenerative purposes, there is a high demand for viable and active cells. A big issue is to have enough viable cells available at any given time. One solution is cryopreservation. In this context, DMSO is used as cryoprotective agent (CPA) along with fetal bovine serum for nutrient supply and stress shielding effects. To use these cells for human clinical studies, it is important to eliminate the serum to prevent foreign immune reactions and virus transmittance and DMSO for its toxic effect. In this study a serum free cryopreservation solution and protocol has been established. The combination of methylcellulose and poloxamer 188 provide the basis for the new CPA. Other additves are -tocopherol, ectoine, prolin and ascorbic acid. The CPAs were examined with 3T3-cells and multipotent stromal cells from the common marmoset monkey (Callithrix jacchus). The cells were preserved with various CPA concentrations, incubation times and different cooling rates. To enable a higher throughput of encouraging conditions a fluorescence microscopy analysis was used. The use of methylcellulose, poloxamer 188 and -tocopherol enables the reduction of DMSO [up to 2.5% (v/v)] and the elimination of serum without viability losses compared to control

Impredicative Encodings of (Higher) Inductive Types

Postulating an impredicative universe in dependent type theory allows System F style encodings of finitary inductive types, but these fail to satisfy the relevant {\eta}-equalities and consequently do not admit dependent eliminators. To recover {\eta} and dependent elimination, we present a method to construct refinements of these impredicative encodings, using ideas from homotopy type theory. We then extend our method to construct impredicative encodings of some higher inductive types, such as 1-truncation and the unit circle S1

A Calculus of Bounded Capacities

Resource control has attracted increasing interest in foundational research on distributed systems. This paper focuses on space control and develops an analysis of space usage in the context of an ambient-like calculus with bounded capacities and weighed processes, where migration and activation require space. A type system complements the dynamics of the calculus by providing static guarantees that the intended capacity bounds are preserved throughout the computation

Encapsulating Non-Human Primate Multipotent Stromal Cells in Alginate via High Voltage for Cell-Based Therapies and Cryopreservation

Alginate cell-based therapy requires further development focused on clinical application. To assess engraftment, risk of mutations and therapeutic benefit studies should be performed in an appropriate non-human primate model, such as the common marmoset (Callithrix jacchus). In this work we encapsulated amnion derived multipotent stromal cells (MSCs) from Callithrix jacchus in defined size alginate beads using a high voltage technique. Our results indicate that i) alginate-cell mixing procedure and cell concentration do not affect the diameter of alginate beads, ii) encapsulation of high cell numbers (up to 10×106 cells/ml) can be performed in alginate beads utilizing high voltage and iii) high voltage (15–30 kV) does not alter the viability, proliferation and differentiation capacity of MSCs post-encapsulation compared with alginate encapsulated cells produced by the traditional air-flow method. The consistent results were obtained over the period of 7 days of encapsulated MSCs culture and after cryopreservation utilizing a slow cooling procedure (1 K/min). The results of this work show that high voltage encapsulation can further be maximized to develop cell-based therapies with alginate beads in a non-human primate model towards human application.DFG/EXC/62/

Homotopy-initial algebras in type theory

We investigate inductive types in type theory, using the insights provided by homotopy type theory and univalent foundations of mathematics. We do so by introducing the new notion of a homotopy-initial algebra. This notion is defined by a purely type-theoretic contractibility condition which replaces the standard, category-theoretic universal property involving the existence and uniqueness of appropriate morphisms. Our main result characterises the types that are equivalent to W-types as homotopy-initial algebras

Phenotypic and Genotypic Characteristics of Members of the Genus Streptobacillus

The genus Streptobacillus (S.) remained monotypic for almost 90 years until two new species were recently described. The type species, S. moniliformis, is one of the two etiological agents of rat bite fever, an under-diagnosed, worldwide occurring zoonosis. In a polyphasic approach field isolates and reference strains of S. moniliformis, S. hongkongensis, S. felis as well as divergent isolates were characterized by comparison of molecular data (n = 29) and from the majority also by their physiological as well as proteomic properties (n = 22). Based on growth-independent physiological profiling using VITEK2-compact, API ZYM and the Micronaut system fastidious growth-related difficulties could be overcome and streptobacilli could definitively be typed despite generally few differences. While differing in their isolation sites and dates, S. moniliformis isolates were found to possess almost identical spectra in matrix-assisted laser desorption ionization-time of flight mass spectrometry and Fourier transform infrared spectroscopy. Spectroscopic methods facilitated differentiation of S. moniliformis, S. hongkongensis and S. felis as well as one divergent isolate. Sequencing of 16S rRNA gene as well as functional genes groEL, recA and gyrB revealed only little intraspecific variability, but generally proved suitable for interspecies discrimination between all three taxa and two groups of divergent isolates.Hessian Ministry for the Environment, Climate Change, Agriculture and Consumer Protection (HMUKLV)Hessian Ministry for the Environment, Climate Change, Agriculture and Consumer Protection (HMUKLV

Human Amniotic Membrane: A review on tissue engineering, application, and storage

Human amniotic membrane (hAM) has been employed as scaffolding material in a wide range of tissue engineering applications, especially as a skin dressing and as a graft for corneal treatment, due to the structure of the extracellular matrix and excellent biological properties that enhance both wound healing and tissue regeneration. This review highlights recent work and current knowledge on the application of native hAM, and/or production of hAM-based tissue-engineered products to create scaffolds mimicking the structure of the native membrane to enhance the hAM performance. Moreover, an overview is presented on the available (cryo) preservation techniques for storage of native hAM and tissue-engineered products that are necessary to maintain biological functions such as angiogenesis, anti-inflammation, antifibrotic and antibacterial activity