Cholesterol can stimulate secretion of apolipoprotein B by cultured human hepatocytes.

During a 5 day cultivation of human hepatocytes in a primary culture the secretion of apolipoprotein B was measured by enzyme-linked immunosorbent assay. Density-gradient ultracentrifugation demonstrated that the majority of the secreted apolipoprotein B was associated with the very-low-density lipoprotein fraction. Exposure of the cells to cholesterol (5-100 micrograms/ml) resulted in a dose-dependent increase in apolipoprotein B secretion rate.

Heterogeneity of endothelium in human aorta. A quantitative analysis by scanning electron microscopy.

Scanning electron microscopy was used to characterize a silver-stained endothelial surface of human aorta and iliac artery. The autopsy material was taken 1-3 h after death from two age groups: group A (0-7 yr) and group B (40-75 yr). The mean cell density per 1 mm2 in the arteries of group A was significantly higher than in the arteries of group B which lie outside ostia, fatty streaks and plaques. In adult arteries the cell density over the plaque was significantly lower than in the regions overlying a fatty streak or uninvolved surface. The luminal surface of child arteries outside high hemodynamic stress zones is a homogeneous sheet covered with exceptionally small (less than 400 micron2) and medium (400-800 micron2) cells. Large (800-1200 micron2) and giant (1200-8000 micron2) endothelial cells emerge only in fatty streaks of child arteries. The luminal surface of adult arteries is a heterogeneous monolayer covered with polymorphic cells both in regions unaffected by atherosclerosis and over the fatty streak and plaque. Giant and large endothelial cells account for 25-41% of the total cell population of adult arteries, occupying more than 40% of the surface in the latter.

[Scanning microscopy of hamster cells transformed by herpes simplex virus type 2]. / Rastrovaia mikroskopiia kletok khomiachka, transformirovannykh virusom prostogo gerpesa tipa 2.

Scanning microscopy was used to examine the features of morphology and attachment to a solid substrate of a transformed and tumor lines of hamster cells. These cell lines differed from normal hamster fibroblasts by changes in the mode of attachment and the degree of flattening on the solid substrate, relief of the cell surface and pattern of intercellular interactions. The observed morphological changes correlated with the degree of cell transformation.

[Heterogeneity of human aortic and arterial endothelium: quantitative study using scanning electron microscopy]. / Geterogennost' éndoteliia aorty i arterii cheloveka: kolichestvennoe izuchenie s pomoshch'iu rastrovoi élektronnoi mikroskopii.

Endothelial lining of the aorta and iliac artery of children under 7 years of age is a homogeneous layer covered with small and medium-sized cells. Large and giant endotheliocytes can only be seen in lipid streaks. In adults with marked atherosclerosis aged 40-75 years, the surface of aortal and arterial lumen is a heterogeneous monolayer covered with polymorphous cells. In lipid streaks and on plaques large and giant endotheliocytes account for 25-41% of total cell population, with giant cells covering up to 50% of the plaque surface. It is suggested that monolayer areas of low and very low density, covered with large and giant cells, can be morphologic markers of arterial involvement in the atheromatous process.

Quantitative SEM-analysis of adhesive and thrombogenic properties of vascular prostheses.

The perfusion technique to measure the relative adhesive and thrombogenic indices of vascular prostheses by a quantitative scanning electron microscopy has been described. To normalize the experiments with different samples of plasma we compared the adhesive and thrombogenic properties of the analyzed prostheses with those of normal and denuded human umbilical vein. The results indicate that adhesive and thrombogenic indices of Dardik, Bakulev and Gore-Tex grafts approximate to those of the non-damaged umbilical vein, while the same indices of Solcograft-P prostheses are considerably higher. The method may be useful for standardizing the properties of new prostheses and bioimplants for cardiovascular surgery.

Aortic endothelium of alloxan diabetic rabbits: a quantitative study using scanning electron microscopy.

Scanning electron microscope studies of the aorta and other major arteries have been performed in alloxan-induced diabetic rabbits. After 5 weeks, a variety of structural abnormalities of the endothelial lining were detected including a significant increase in the number of argyrophilic cells and an increased number of craters or openings in the endothelial junctional region. Evidence of more extensive micro-damage was present after 5 months duration of diabetes. These zones with structural changes in the endothelial lining of major vessels seem to be areas of high predilection to atherosclerosis in diabetes.

Quantitative SEM analysis of injury to the endothelium of rabbit aorta and carotid artery during experimental atherosclerosis.

The luminal surface of the aorta and the carotid artery in normal and cholesterol-fed rabbits (3 weeks, 6 weeks, and 8 months of alimentary hypercholesterolemia) was studied by scanning electron microscopy (SEM). To study endothelial injury the vessels were perfused and stained under physiological pressure. The frequency of large and small endothelial defects was determined per surface unit of endothelium in the normal and experimental groups of rabbits. Loss of endothelial cells was regarded as a large defect, argyrophilic cells, craters, and stomata were regarded as small ones. It was found that the percentage of regions without endothelial cells was similar in both control rabbits and in rabbits with experimental atherosclerosis (0.005--0.04% of the total surface examined). The frequency of small endothelial defects increased in rabbits after 3 weeks of hypercholesterolemia but decreased to the control level after 6 weeks of hypercholesterolemia. In rabbits with 8 months of hypercholesterolemia the frequency and area of defects outside plaques did not differ from the control group. In the group with hypercholesterolemia for 8 months 39.2% of the plaque surface contained endothelial cells in which there were no distinct silver-stained cell borders. Kevex X-ray spectrometric data of silver topography indicated that the plaque surface without distinct cell borders was not an area devoid of cells. The data obtained do not support the assumption that morphological endothelial injury is the structural precursor of plaque formation.

[Quantitative analysis of lesions of the aortic and carotid artery endothelium in experimental diabetes in rabbits by scanning electron microscopy]. / Kolichestvennyi analiz povrezhdenii éndotelial'nogo pokrova aorty i sonnoi arterii pri éksperimental'nom sakharnom diabete u krolikov metodom rastrovoi élektronnoi mikroskopii.

A significant increase in the number and zone area of argyrophil cells, craters and stomata of the intracellular formations were seen in the aortic and carotid pectoral and peritoneal regions of rabbits with 5-week alloxan diabetes. The number and zone area of vascular de-endothelization did not increase. Cell polymorphism, apart from maintenance of pronounced argyrophilia and micro-injuries, occurred to diabetes of 5-month standing. Deranged properties of the macrovascular endothelial integument may be of great importance in the pathogenesis of atheromatosis in diabetes mellitus.

[Quantitative study of endothelial defects in the aorta and carotid artery in experimental atherosclerosis]. / Kolichestvennoe izuchenie defektov éndoteliia aorty i sonnoi arterii pri éksperimental'nom ateroskleroze.

The inner surface of the aorta and carotid artery in normal rabbits (group 1) and after 3 weeks (group 2), 6 weeks (group 3) and 8 months (group 4) of hypercholesterolemia was studied by scanning electron microscopy. In all the cases the area of de-endothelialized zones was equally small. Incidence of microdefects in the endothelium (argyrophilic cells, craters and stomata) increased in group 2, but decreased in group 3 and group 4 (outside the plaques). No typical endothelium with argyrophilic borders was observed on 39.2% of the plaque surface in group 4, though the cells were present. The data obtained show that vast zones of de-endothelialization do not precede the development of atherosclerotic plaques.