0000000000336428
AUTHOR
Brigitte Vollmar
Genetic dissection of plexin signaling in vivo
Mammalian plexins constitute a family of transmembrane receptors for semaphorins and represent critical regulators of various processes during development of the nervous, cardiovascular, skeletal, and renal system. In vitro studies have shown that plexins exert their effects via an intracellular R-Ras/M-Ras GTPase-activating protein (GAP) domain or by activation of RhoA through interaction with Rho guanine nucleotide exchange factor proteins. However, which of these signaling pathways are relevant for plexin functions in vivo is largely unknown. Using an allelic series of transgenic mice, we show that the GAP domain of plexins constitutes their key signaling module during development. Mice …
Intravital fluorescence microscopy for the study of leukocyte interaction with platelets and endothelial cells
Publisher Summary This chapter introduces the techniques of intravital microscopy as a tool to study the microcirculation in intact animals under conditions of oxidative stress. Intravital fluorescence microscopy can be performed with almost all types of epiillumination microscopes available. The introduction of fluorescent dyes and refined epiillumination techniques has significantly advanced the possibilities of intravital microscopic studies of the liver microcirculation, including quantitative analyses of both circulatory parameters and cellular mechanisms. Using appropriate dyes, intravital microscopy allows the study of (1) microvascular perfusion, (2) leukocyte-endothelial cell inter…
Collagen membranes of dermal and pericardial origin-In vivo evolvement of vascularization over time.
Aim of the study was to compare the evolvement of vascularization over time of collagen membranes (CMs) of dermal and pericardial origin in an in vivo animal study. Twenty-eight mice underwent implantation of three commercially available CM derived from porcine dermis (homogenous structure: CM1 (Control 1) and bilayer structure: CM2 [Control 2]), from porcine pericardium (CM3; Test 1) as well as CM3 sprayed with silica-enhanced nanostructured hydroxyapatite (CM4, Test 2). After 3, 6, 9, and 12 days, intravital fluorescence microscopy was conducted for determination of capillary diameter, density, flow, and length. At Day 12, samples were examined immunohistologically for expression of fibro…