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Biomedical subjects

R C Wagner

Publications and source records attributed to R C Wagner.

44 records · Page 3Linked to original sources
PubMed1972

Biochemical characterization and cytochemical localization of a catecholamine-sensitive adenylate cyclase in isolated capillary endothelium.

Capillaries were isolated from epididymal fat, and a catecholamine-sensitive adenylate cyclase found in these capillaries was characterized. The effect of various hormones on the accumulation of adenosine 3':5'-cyclic monophosphate in capillary endothelial cells was determined and the cyclase was found to exhibit mixed alpha and beta characteristics. Cyclase was cytochemically localized in these endothelial cells with 5'-adenylyl-imidodiphosphate as a specific cyclase substrate and alloxan as a specific cyclase inhibitor. Lead imidodiphosphate was precipitated at or near the site of cyclase activity upon hydrolysis of 5'-adenylyl-imidodiphosphate by cyclase. This reaction product was observed primarily on the luminal surface of intact capillaries, in micropinocytic invaginations, in free vesicles within the cytoplasm, and in the intracellular junctions.

Adenosine Triphosphate↗
PubMedDate not supplied

Morphometric changes in pericyte-capillary endothelial cell associations correlated with vasoactive stimulus.

The arterially-derived capillaries of the eel rete mirabile are heavily invested with highly arborized pericytes. By perfusing vasoactive agents through these capillaries, measuring changes in outflow volume and analyzing alterations in capillary and pericyte morphology a set of vasoactive agent-correlated changes were quantified. Morphometric analysis of the capillary ultrastructure revealed that alterations in flow and appearance were associated with changes in the extension of pericyte processes. These responses of the arterial pericytes to the vasoactive agents used in this study suggest that pericyte contraction alters the architecture of the arterially-derived capillaries of the rete in a manner which affects their permeability.

Anguilla↗
PubMedDate not supplied

Rapidly-frozen, cultured, human endothelial cells: an ultrastructural and morphometric comparison between freshly-frozen and glutaraldehyde prefixed cells.

Cultured, human endothelial cells from the iliac vein were divided into two groups for rapid-freezing using liquid helium in a Heuser-type cryopress freezing machine. The first group of cells was prefixed in buffered 2% glutaraldehyde solution whereas the second group was freshly-frozen. Following freeze substitution and embedding, morphometric analysis was carried out on thin sections of groups of endothelial cells. Measurements showed that glutaraldehyde prefixation significantly increases the numerical and volume densities of the vesicles compared to those of the freshly-frozen cells. However, the fact that no significant increase was demonstrated either in the numerical or volume densities of the caveolae, and that no significant change was observed in the ratio of the cell perimeter to area, suggests that the membrane source for these extra vesicles is internally generated. Studies are currently under way to identify the source of this membrane.

Cells, Cultured↗