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We studied the early pattern of neural tube (NT) vascularization in quail embryos and chick-quail chimeras. Angioblasts appeared first in the dorsal third at Hamburger and Hamilton (HH) stage 19 as single, migrating cells. Their distribution did not correspond to a segmental pattern. After this initial dorsal immigration, endothelial sprouts invaded the NT(More)
The soluble Ca2+-binding protein parvalbumin (PV) is expressed at high levels in fast-twitch muscles of mice. Deficiency of PV in knockout mice (PV -/-) slows down the speed of twitch relaxation, while maximum force generated during tetanic contraction is unaltered. We observed that PV-deficient fast-twitch muscles were significantly more resistant to(More)
The structural organization of articular cartilage from the medial femoral condyle of young adult rabbits has been examined after processing according to an improved fixation procedure. By using recently developed stereological methods, a quantitative analysis of chondrocyte number, surface area, volume, and matrix volume per cell was carried out in the(More)
We asked, whether, in the blood of avian embryos, endothelial precursor cells circulate that actually contribute to the growing vascular system in and around the central nervous system (CNS). We compared the morphology and distribution of QH1-positive cells after transplantation of quail paraxial mesoderm, after blood transfusion, in quail-chick parabiosis,(More)
Visualisation of oligodendrocytes by fluorochrome labelling in fresh tissue is a relatively recent innovation, but its widespread applicability in comparative analyses between different regions of the brain has been hampered by the limited survival time of excised preparations. We here applied the technique of impaling and injecting these cells with Lucifer(More)
The dynamic events at the front of locomoting blebbing Walker carcinosarcoma cells [Keller and Bebie, Cell Motil. Cytoskeleton 33:241-251, 1996] are interpreted on the basis of an analysis of the actin cytoskeleton and its relationship to the plasma membrane in fixed cells using a novel double-staining procedure. The data show that blebs are formed where(More)
The Ca(2+)-binding proteins parvalbumin (PV) and calbindin D-28k (CB) are key players in the intracellular Ca(2+)-buffering in specific cells including neurons and have profound effects on spatiotemporal aspects of Ca(2+) transients. The previously observed increase in mitochondrial volume density in fast-twitch muscle of PV-/- mice is viewed as a specific(More)
The molecular components surrounding a neurone serve as recognition cues for the nerve terminals and glial processes that contact them and the constellations formed by these inputs will therefore be determined by the blend of adhesive and repulsive components therein. Using immunohistochemical methods, we observed that the large extracellular(More)
Spontaneously migrating Walker carcinosarcoma cells usually form lamellipodia at the front. Combined treatment with 10(-5)M colchicine and 10(-7)M latrunculin A produces large defects in the cortical F-actin layer at the leading front and suppresses lamellipodia. However, the cortical actin layer at the rear is intact and shows myosin IIA accumulation.(More)
A potential association between hyaluronan and unmyelinated nerve fibres in the PNS (rat skin and iris) and CNS (rat retinal inner plexiform and nerve fibre layers) was investigated at the ultrastructural level using two different hyaluronan-binding probes (link protein-gold and aggrecan-gold). Neuronal and glial cell plasma membranes, as well as the(More)