Mukosaschädigung im Gastrointestinaltrakt der Ratte

Die Synthese von Prostaglandinen (PG) und Stickstoffmonoxid sowie capsaicin-sensitive afferente Neurone sind bedeutend für die Magenprotektion. Das Hauptenzym für die PG-Synthese, die Cyclooxygenase existiert in zwei Isoformen: COX-1 wird in vielen Geweben konstitutiv exprimiert, dagegen ist die basale Expression von COX-2 gering. Nichtsteroidale Antiphlogistika (NSA) hemmen beide COX und induzieren gastrale Nebenwirkungen. Obwohl selektive COX-2 Inhibitoren (NS-398, DFU, Rofecoxib) unter basalen Bedingungen geringere Gastrotoxizität als NSA zeigen, induzieren sie bei Ischämie-Reperfusion oder Hemmung der NO-Synthese Magenschäden wie NSA. Unter diesen Bedingungen wird die COX-2 induziert und COX-2 synthetisierte PG unterstützen die Minimierung von gastrointestinalen Schäden. COX-2 Inhibitoren verzögern die Heilung von Magenulzera und es wurden physiologische Funktionen der COX-2 identifiziert. Die Vorteile von COX-2 Inhibitoren gegenüber NSA gehen unter diesen Bedingungen verloren.The synthesis of prostaglandins (PG) and nitric oxide as well as capsaicin-sensitive afferent neurons are important for gastric mucosal protection. The keyenzyme for PG-synthesis, the cyclooxygenase exists in two isoforms: COX-1 is expressed in many tissues, whereas the basal expression of COX-2 is low. Nonsteroidal anti-inflammatory drugs (NSAID) inhibit both COX and induce gastrointestinal side effects. Although selective COX-2 inhibitors (NS-398, DFU, Rofecoxib) under basal conditions show lower gastotoxicity than NSAID, under ischemia-reperfusion or inhibition of nitric oxide synthesis they induce gastric injury like NSAID. Under these conditions COX-2 is induced and COX-2 synthetized PG support the reduction of gastrointestinal lesions. Selective COX-2 inhibitors delay the healing of gastric ulcers and physiological functions of COX-2 were identified. The advantages of selective COX-2 inhibitors against NSAID under these conditions were lost

Zebrafish as an orthotopic tumor model for retinoblastoma mimicking routes of human metastasis

Background: Retinoblastoma (RB) is the most common eye cancer in children that has a high mortality rate when left untreated. Mouse models for retinoblastoma have been established but are time- and cost-intensive. The aim of this work was to evaluate an orthotopic transplantation model of retinoblastoma in zebrafish that also allows for tracking migratory routes and to explore advantages and disadvantages with respect to drug testing. Methods: Three fluorescence-labeled retinoblastoma cell lines (RB355, WERI-RB-1, Y79) were injected into the left eye of two-day-old zebrafish, while the un-injected right eye served as control. The migratory trajectories of injected retinoblastoma cells were observed until 8 days post injection (dpi), both in lateral and dorsal view, and measuring fluorescence intensity of injected cells was done for RB355 cells. Results: Time until the onset of migration and routes for all three retinoblastoma cell lines were comparable and resulted in migration into the brain and ventricles of the forebrain, midbrain and hindbrain. Involvement of the optic nerve was observed in 10% of injections with the RB355 cell line, 15% with Y79 cells and 5% with WERI-RB-1 cells. Fluorescence intensity of injected RB355 cells showed an initial increase until five dpi, but then decreased with high variability until the end of observation. Conclusion: The zebrafish eye is well suited for the analysis of migratory routes in retinoblastoma and closely mirrors patterns of retinoblastoma metastases in humans

The Hinrichsen embryology collection

The number of human embryology collections is very limited worldwide. Some of these comprise the $\textit {Carnegie Collection, Kyoto Collection, and the Blechschmidt Collection}$. One further embryonic collection is the $\textit {Hinrichsen Collection}$ of the Ruhr University Bochum, Germany, which also contains very well-preserved embryos/fetuses, along with approximately 16,000 histological sections. The digitization of this collection is indispensable to enable conservation of the collection for the future and to provide a large group of embryologists, researchers, and physicians access to these histological slides. A small selection of these scans is available at the website of the Digital Embryology Consortium [https://­human-embryology.org/wiki/Main_Page]