Interleukin-2- and phytohemagglutinin-activated proliferation of human T-lymphocytes is accompanied by stimulation of phosphoinositide turnover.

Interleukin-2 (IL-2) was more effective than phytohemagglutinin (PHA) in increasing the proliferative activity of human T-lymphocytes. Unlike PHA, IL-2 stimulated phosphoinositide turnover (PI turnover) only in those T-lymphocytes which had been preactivated by PHA with IL-2 and expressed the IL-2 receptors. The effect of PHA on PI turnover was, in general, stronger than that of IL-2. These results indicate that IL-2 and PHA-activated proliferation of human T-lymphocytes is accompanied by stimulation of PI turnover. However, IL-2-induced proliferative response may not be a direct consequence of PI turnover stimulation in these cells.

Noradrenaline induces the polyploidization of smooth muscle cells: the synergism of second messengers.

The effect of noradrenaline (NA) on DNA replication of cultured smooth muscle cells (SMC) isolated from rat aorta was examined. It was found that 10 microM NA significantly increased (approximately by twofold) the frequency of tetraploid cells. Cultivation of 4C cells isolated by flow cytometric cell sorting revealed that they were true polyploid cells. This receptor-mediated effect of NA was blocked only by simultaneous action of alpha- and beta-adrenoreceptor antagonists. SMC polyploidization was also stimulated by simultaneous application of direct activators of "second messenger" systems forskolin and phorbolmyristate-acetate. Thus, NA may be one of mediators of the "hypertensive" response of vessel wall SMC, which probably occurs due to synergism of two second messenger systems.

Seasonal variations of DNA-synthesis in intestinal epithelial cells of hibernating animals--2. DNA-synthesis in intestinal epithelial cells of ground squirrel (Citellus undulatus) during autumn and late hibernation season.

1. DNA-synthesis was found to be gradually reduced in the intestinal crypt cells of ground squirrel during autumn at the time of preparation for hibernation and gradually rose during late hibernation season in February-March at the time of preparation for arousal. 2. A conclusion is made on the seasonal variations in cell replacement of true hibernators.

[Effect of extracorporeal sorption on the content of free intracellular calcium of the leukocytes in atopic bronchial asthma]. / Issledovanie vliianiia ékstrakorporal'noi sorbtsii na soderzhanie svobodnogo vnutrikletochnogo kal'tsiia v leikotsitakh pri atopicheskoi bronkhial'noi astme.

Antigen-IgE-antibody interaction on the cell surface in an allergic reaction increases methylation of phospholipids of a cell membrane making it permeable for Ca2+ ions. Therefore of interest is a study of free intracellular Ca2+ concentration from a view-point of development of atopic bronchial asthma and the use of extracorporal methods of its therapy permitting the elimination of IgE-antibodies from the blood flow. The level of intracellular Ca2+ in the leukocytes of patients with atopic bronchial asthma was studied. It has been shown that 1. the fraction of leukocytes with a higher level of intracellular Ca2+ in patients with atopic bronchial asthma was increased as compared to healthy donors; 2. extracorporal sorption results in a decrease in the number of leukocytes with high Ca concentration.

The intestinal epithelial cells of ground squirrel (Citellus undulatus) accumulate at G2 phase of the cell cycle throughout a bout of hibernation.

1. The mitotic index was found to be greatly reduced in the intestinal crypt cells of ground squirrel during bout of hibernation. The percentage of mitosis rose abruptly at least 2 hr after arousal. 2. An increase in the number of G2 cells was found in the intestinal tract of ground squirrel during bouts of hibernation. 3. The conclusion can be drawn that the cells are progressing steadily through the cell cycle. The cells accumulate at G2 in hibernation. 4. It was assumed that the block in G2 prevents the cells from possible damage in mitosis under hypothermia accompanying hibernation and, therefore, it represents an adaptive reaction.

[Concentration of erythrocyte-based magnetic carriers in the vascular bed]. / Kontsentrirovanie magnitnykh nositelei na osnove éritrotsiov v sosudistom rusle.

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.

Determination of total intracellular lipid content by flow cytofluorometry.

It was demonstrated that perylenoyl-labeled triglyceride, rac-1,2-dioleoyl-3-[9(3-perylenoyl)nonanoyl]glycerol (PLTG), specifically stains the intracellular lipids in formalin-fixed and non-fixed cells in situ and in suspension. The fluorescence of labeled cells was registered on a FACS-II cytofluorometer. It was found that the mean intensity of fluorescence in PLTG-labeled cells of various types, both fixed and non-fixed, correlates with their total lipid content. There was no correlation, however, between the mean intensity of fluorescence and intracellular levels of lipids belonging to different classes: phospholipids, triglycerides, cholesterol or cholesteryl esters.

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.

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.