Stereo-elektronenmikroskopische Untersuchungen an der Venenwand

The endothelial surface of large veins of rabbit: scanning electron microscopic observations

The following veins of the rabbit were fixed by perfusion and studied systematically by scanning electron microscopy: sagittal sinus, confluence of sinuses, external jugular vein, superior vena cava, inferior vena cava, greater saphenous, and femoral veins. One result is that the shape and arrangement of endothelial cells of the veins are obviously influenced by hemodynamic shear forces. Two types of subendothelial fibres were demonstrated: "cross-fibers" which correspond to the circular inner muscle cells of the media, and "longitudinal fibers" which correspond to the intimal meshwork of connective tissue fibers. Regional differences are demonstrated in the occurrence of these fibres. Moreover, five morphologically different venous valve types are observed. The functional significance of these different valve types is not yet known.

Scanning electron-microscopic study of the surface characteristics of neoplastic endothelial cells of blood vessels

The morphological surface characteristics of neoplastic endothelial cells of blood vessels induced by oral administration of 1,2-dimethylhydrazine dihydrochloride in mice were studied by scanning electron microscopy. The interconnecting vascular channels were lined by malignant endothelial cells which formed bridges, cord-like structures and had extended cytoplasmic processes which made the network more intricate. The endothelial cells were often in close approximation to each other and exhibited irregular growth patterns and orientation. The cell surface displayed a rugged, terrace-like microcontour of elevations, depressions, blebs and nodular structures. These findings correlate with the earlier morphological observation obtained by transmission electron microscopy.