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Biomedical subjects

A N Orekhov

Publications and source records attributed to A N Orekhov.

At least 181 records · Page 10Linked to original sources
PubMed1985

Lipids in cells of atherosclerotic and uninvolved human aorta. I. Lipid composition of aortic tissue and enzyme-isolated and cultured cells.

Phospholipid, triglyceride, cholesterol, and cholesteryl ester contents were measured in unaffected and atherosclerotic areas of human aorta and in a suspension of enzyme-isolated cells from these segments. Aortic tissue and the cells isolated from it, as well as intimal and medial cells, significantly differ in lipid content. As lipoidosis develops in an atherosclerotic lesion, lipids accumulate unevenly in the tissue and cells. In zones of fatty infiltration, lipids accumulate, apparently, mainly inside cells while in the fatty streak and atherosclerotic plaque they predominate in the extracellular space. In a suspension of cells derived from both an atherosclerotic lesion and the underlying media, cholesteryl esters are the main component of excessive fat. In the primary culture of cells enzyme-isolated from unaffected intima, fatty streak, and plaque, the lipid content and composition are retained until Days 12 to 14 and are similar to those of freshly isolated cells.

Aorta↗
PubMed1985

Lipids in cells of atherosclerotic and uninvolved human aorta. II. Lipid metabolism in primary culture.

[3H]Acetate and [3H]oleate were used to evaluate the rate of lipid synthesis in smooth muscle cells of human aorta. Experiments were carried out in primary cultures derived from the intima and media of unaffected and atherosclerotic vascular segments. The obtained results indicate that the rate of lipid synthesis in cells cultured from fatty streaks, atherosclerotic plaques, and underlying media is higher than in cells cultured from an uninvolved intima and media, respectively. The highest level of the label incorporation was observed in the fraction of phospholipids. In cultures obtained from fatty streaks and plaques, an increased incorporation of the labeled precursors into phospholipids, triglycerides, free sterols, and sterol esters was registered. The highest relative increase occurred in the fraction of sterol esters, the rate of acetate inclusion being five- to sixfold higher compared to the cell cultures derived from unaffected aortic segments. A direct and very close correlation was found between the rate of lipid synthesis and lipid levels in cells of normal and atherosclerotic aorta. The role of intracellular lipid metabolism disorders in the accumulation of excessive fat by "atherosclerotic" cells is discussed in this report.

Acetates↗
PubMed1985

[Cellular composition and biochemical characteristics of the human aorta].

Development of atherosclerotic lesions in the human aortic intima has been studied using morphological and biochemical methods. It is shown that the sublayers of the human aortic intima are involved in the atherosclerotic processes in different degree. Such manifestation of atherosclerosis as lipid and collagen take up and intimal thickness are especially connected with juxtluminal layer of the intima. Stellate cells (one of the 4 morphological types in the intima) are most closely correlated with these processes. The problems of the origin and possible role of the intima cells in the atherosclerosis are discussed.

Adult↗
PubMed1985

[Concentration of erythrocyte-based magnetic carriers in the vascular bed].

The in vivo and in vitro experiments have shown that magnetic erythrocytes (loaded with ferromagnetic material) can be retained in certain sites of the vascular bed. Magnetic erithrocytes could be concentrated in the abdominal part of the dog aorta using a small permanent magnet fixed on the outer wall of the aorta.

Animals↗
PubMed1984

Content and localization of fibronectin in normal intima, atherosclerotic plaque, and underlying media of human aorta.

Fibronectin was extracted from normal and atherosclerotic areas of human aorta by urea and heparin and sonication of the tissue. Fibronectin content was determined by enzyme-linked immunosorbent assay (ELISA). In unaffected media and the media underlying an atherosclerotic plaque, the fibronectin content is approximately the same and much lower than in the intimal layer. In the plaque, the fibronectin content is 2-3-fold lower compared to the unaffected intima. Using indirect immunofluorescence it was found, that fibronectin is localized in the media along elastic laminae; in unaffected intima its fibers are evenly distributed throughout the layer, while in the plaque all fibronectin is concentrated in the cap.

Adult↗
PubMed1984

Dissociated cells from different layers of adult human aortic wall.

Cells isolated from a fixed adult human aorta by alcoholic-alkaline dissociation retain their intrinsic shape. They are represented by four major morphological types: stellate, elongated, elongated with side processes, and irregularly shaped cells. All the four types of cells were found in the elastic-hyperplastic intimal sublayer ; elongated and irregularly shaped cells were mainly observed in the musculoelastic sublayer and in the media. Cell density in the atherosclerotic lesion is higher than normal, the number of stellate cells being increased more substantially compared to other cell types. The origin of stellate cells and other morphological cell types, and reasons for their disproportionate accumulation in the atherosclerotic intima are discussed.

Adult↗
PubMed1984

Heterogeneity of human aortic cells in regard to RNA content.

Cells of human aorta were isolated by dispersing the tissue with collagenase and elastase. The isolated cells were stained in suspension by the acridine orange fluorescent stain. The intensity of red fluorescence (greater than 580 nm) corresponding to the RNA content was measured in each individual cell and registered in a FACS II flow cytofluorometer. It was established that a cell population of human aorta is heterogenous with respect to RNA content. In a population of isolated cells, one can distinguish two subpopulations: (A) small cells with low RNA content, and (B) large cells with high RNA content. The ratio of both cell types varies in intima and media, and different types of atherosclerotic lesions. The share of cells belonging to subpopulation A is lower in media compared to intima. In intima, the number of these cells grows with the degree of atherosclerotic lesion. Possible reasons for the discovered metabolic heterogeneity of human aortic cells and prospects for the application of flow cytofluorometry to a research into cellular mechanisms of atherosclerosis is discussed.

Adult↗
PubMed1984

Enzymatic detoxication of superoxide anion-radicals and lipoperoxides in intima and media of atherosclerotic aorta.

Unusually high activities of the "antioxidative" enzymes (superoxide dismutase, glutathione peroxidase) have been found in the cells isolated from the intima and media of normal human aorta. The activities of "antioxidative" enzymes of the intima and media of the human aorta in different types of atherosclerotic lesions (lipid spots, fibrous plaques) have been demonstrated to be greatly lowered.

Adult↗
PubMed1984

[Decrease in the lipid content of human atherosclerotic aorta cells as affected by compounds increasing the intracellular level of cyclic AMP].

A study was made of the effect of cholera toxin, an adenylate cyclase activator, and methylisobutylxanthine, an inhibitor of cAMP phosphodiesterase, on the content of main class lipids in intimal cells isolated from unaffected and atherosclerotic areas of the human aorta in primary culture. Both the agents did not change the content of lipids in the cells obtained from the normal intima. Cholera toxin and methylisobutylxanthine decreased the levels of cholesterol esters and triglycerides in the cells isolated from fatty layers and atherosclerotic patches. The agents under study did not produce any influence on the levels of phospholipids and free cholesterol in all cases investigated. It is assumed that compounds that increase intracellular cAMP may contribute to lipoidosis diminution in vivo.

1-Methyl-3-isobutylxanthine↗
PubMed1984

[Immunomorphological study of fibronectin localization in a primary human aorta cell culture].

Using indirect immunofluorescence, fibronectin localization in primary culture of human aortic cells was studied. Intimal and medical cultures obtained from normal and atherosclerotic zones were investigated. Four morphological cell types, previously described elsewhere, were found in these cultures. All the cell types were able to synthesise fibronectin and to form the extracellular matrix in culture. But the pattern and quantity of this matrix differs in different cell types. Elongate cells formed a fine network of fibronectin on their surface, but stellate, polygonal and asymmetric cells contained only several fibers of extracellular fibronectin. There was difference in the fibronectin localization pattern of the surface of cells, isolated from intima and media as well as from normal and atherosclerotic zones.

Aorta↗
PubMed1984

Primary cultures of enzyme-isolated cells from normal and atherosclerotic human aorta.

A technique has been developed for isolating cells from the intimal and medial layers of the human aorta by enzymatic dispersion. After mechanical separation of intima, media and adventitia the intima and the media were dispersed by collagenase and elastase. Enzyme-isolated cells seeded in the culture with at a frequency of 30 to 50%. In the primary culture differentiated aortic cells were morphologically heterogenous. It was possible to define four main types of cells according to their shape: polygonal, elongated, asymmetrical and stellate. Polygonal and stellate cells are found only in cultures of grossly normal intima, whereas elongated and asymmetric cells are found in practically all cultures. The ratio of elongated to asymmetric cells in cultures obtained from healthy aorta and atherosclerotic plaque is more or less the same at approximately 3:1. In cultures of fatty streaks the proportion of asymmetric cells exceeds 50%. Using immunofluorescence, all four types of cell were identified as smooth muscle cells. The possible reasons for the cellular polymorphism in primary culture and the prospects of utilizing this culture for the study of cellular aspects of atherosclerosis' pathogenesis are discussed.

Adult↗
PubMed1984

Regression of atherosclerotic manifestations in primary culture of human aortic cells: effects of prostaglandins.

The effect of different prostaglandins on cell proliferation and intracellular lipid content in primary culture of human aortic cells has been studied. It was demonstrated that prostacyclin, its stable analogues (carbacyclin and 6 beta-PGI1), and prostaglandins E1, E2, D2 taken in the concentration of 0.5 micrograms/ml and 10 micrograms/ml decreased the 3H-thymidine uptake into cultured intimal smooth muscle cells by 2-3-fold. Carbacyclin and 6 beta-PGI1 also lowered by 1.5-2-fold the triglyceride and cholesteryl ester levels in cells cultured from atherosclerotic lesions. Prostaglandins E1, E2, D2 in the concentration of 10 micrograms/ml decreased by 20-40% total cholesterol level in cultured cells.

Adult↗
PubMed1984

Cellular composition of atherosclerotic and uninvolved human aortic subendothelial intima. Light-microscopic study of dissociated aortic cells.

Alcoholic-alkaline dissociation was used in the study of cellular composition of human aorta. Cells were isolated from an uninvolved intima and intima with different types of atherosclerotic lesions: fatty infiltration, fatty streak, and atherosclerotic plaque. In the isolated suspension we evaluated the ratio of four previously described morphologic forms of cells: stellate, elongated, elongated with side processes, and flat cells of irregular shape. It was demonstrated that the quota of stellate cells in an atherosclerotic lesion considerably exceeds that of the normal intima. For elongated cells the opposite is true. The other two cell forms are represented in the uninvolved and atherosclerotic intima in approximately equal proportions. Alteration of the ratio of different morphologic forms occurs because of the fact that the number of cells belonging to different morphologic forms increases disproportionately in the lesion zone. Specifically, the number of stellate cells is increased much more substantially, compared with elongated cells.

Adult↗