[COMPARATIVE STUDY OF MECHANICAL STRESS EFFECT ON HUMAN AND ANIMAL ERYTHROCYTES].

Sensitivity of human and animal (bovine, rat, rabbit, equine) erythrocytes to the effect of mechanical stress has been studied. Mechanical stress effect was demonstrated to result in a time-dependent (5-60 min) release of potassium cations out of mammalian erythrocytes and a partial hemolytic cell damage. Herewith the release levels of potassium ions and hemolysis did not coincide for erythrocytes of all the mammals except rabbit ones. The most sensitive to mechanical stress (60 min) by the parameters of hemolytic damage and potassium ion release were rat (32%) and bovine (66%) erythrocytes respectively, the lowest sensitive by both parameters were rabbit ones (about 20%). Implemented correlation analysis has demonstrated a statistically significant negative relation between the values of mechanical hemolysis of mammalian erythrocytes and surface-volumetric ratio of cells (rs = -0.900, P = 0.037). A feasible relationship between the content of phosphatidylethanolamine in mammalian erythrocyte membranes and the level of potassium cation loss under mechanical stress effect is under discussion.

[Effect of C60 fullerene on viscoelastic properties of human erythrocytes membrane].

The effect of C60 fullerene aqueous colloid solution (C60FAS) on viscoelastic properties of human erythrocytes membrane has been studied. It was established that the effect of C60FAS on erythrocytes depends on the medium osmolality and concentration of C60 fullerene in it. In particular, in isotonic solution (0,15 mol/l NaCl) adding C60 fullerene in concentrations from 0,7 to 28 µmol/l did not cause the hemolytic damage of cells. In hypotonic medium when introducing C60 fullerene (7 µmol/l concentration) at the beginning of erythrocyte hemolysis its stimulating effect was maximal and when adding C60FAS in 20 s after hemolysis start no this process stimulation is observed. This points to the changes in viscoelastic properties of erythrocyte membranes even during the first seconds of its interaction with C60 fullerene.

[Effect of cationic and anionic amphiphilic compounds on hypertonic cryohemolysis of mammalian red blood cells].

We studied the effect of derivatives of anionic (sodium decyl- and dodecyl- sulphate) and cationic (trifluoperazine, chlorpromazine) amphiphilic compounds on morphological peculiarities and hypertonic cryohemolysis of human, rabbit, bovine, equine red blood cells. The mentioned substances cause changes in red blood cell shape for all the studied mammals: anionic amphiphils on the discocyte-echinocyte type and cationic ones on discocyte-stomatocyte type. It was revealed a significant antihemolytic activity of the studied substances under hypertonic cryohemolysis of mammalian red blood cells with manifested species differences in the efficiency. The most effective are cationic trifluoperazine and anionic sodium decylsulphate, moreover the latter is much more active for animal red blood cells if compared with human ones.

[Mechanism of protective effect of amphiphilic compounds during hypertonic hemolysis of erythrocytes].

Antihemolytic effect of various amphiphilic compounds under conditions of red blood cell hypertonic hemolysis at different temperatures (0 and 37 degrees C) and cell exposure to diamide was investigated. The level of maximum antihemolytic activity and values of efficient concentrations for all studied substances were lower at 0 degrees C if compared with 37 degrees C. Exposure of erythrocytes to diamide (5 and 10 mmol/l) did not change cell sensibility to hypertonic medium. There has been demonstrated a temperature-dependent decrease in the efficiency of studiedsubstances under hypertonic hemolysis of erythrocytes exposed to 10 mmol/l diamide. Found reduction in efficiency of amphiphiles at low temperature and at high concentration of diamide was probably caused by similar changes of structural and dynamic state of erythrocyte membrane.

[Protecting effect of trifluoroperazine during hyperosmotic erythrocyte shock]. / Zashchitnyl 'effekt triftoroperazina pri giperosmoticheskom shoke 'eritrotsitov

It has been shown that antihemolytic effect of trifluoroperazine is realized directly at the stage of hyperosmotic stress during cell transfer to 4.0 M NaCl and is not the result of preliminary cell treatment by this amphypathic compound. The value of protecting effect of trifluoroperazine is determined by preliminary RBS dehydration condition. Cell treatment by hemin, modifying cytoskeleton and membrane, significantly affects cell sensitivity to hyperosmotic stress both in the presence of trifluoroperazine and without the latter.

[Antihemolytic effect of chlorpromazine on erythrocytes in hyperosmotic and cold shock]. / Antigemoliticheskiiéffekt khlorpromazina pri giperosmoticheskom i kholodovom shoke éritrotsitov.

The combined effect of preliminary dehydration of erythrocytes and the cationic amphiphilic compound, chlorpromazine, on the stability of cells to subsequent hyperosmotic effect, has been studied. A protective effect of chlorpromazine depending on the degree of initial cell dehydration and temperature was found. The results obtained by an addition of the cationic amphiphile at preliminary stages of the experiment and directly in the process of development of hyperosmotic lysis have been compared. A conclusion was drawn that the observed effect is not due to preliminary treatment of cells with chlorpromazine and is therefore unrelated to its influence on the regulatory systems of the cell. It has been shown also that under cold shock conditions the earlier established protective effect of chlorpromazine is also directly realized at the moment of stress exposure, i.e., with a change in temperature.

[Sensitivity of chlorpromazine-modified eryhtrocytes to cold stress]. / Chuvstvitel'nost' modifitsirovannykh khlorpromazinom éritrotsitov k kholodovomu shoku.

Development peculiarities of hypertonic cold shock of erythrocytes modified with chlorpromazine were studied, maximum protection effect under cooling of cells is registered when using chlorpromazine in the concentration 7 x 10(-5) M. Spectrin denaturation does not change general pattern of the effect of different concentrations of amphipat on sensitivity of erythrocytes to the cold shock but it sensitizes cells modified by chlorpromazine (7 x 10(-5) M) to the further cooling. Differences between native cells and erythrocytes with denatured spectrin are levelled at higher concentrations of amphypat, certain protective effect being observed at certain values of the medium tonicity.

[The effect of chlorpromazine on the temperature and osmotic sensitivity of erythrocytes]. / Deistvie khlorpromazina na temperaturnuiu i osmoticheskuiu chuvstvitel'nost' éritrotsitov.

The effect of chlorpromazine on the development of cold shock in erythrocytes exposed to sodium chloride was shown to depend on the tonicity of the medium in which the cells were cooled from 37 degrees C down to 0 degrees C as well as on the amphipate concentration. After cooling of erythrocytes in a NaCl (0.75-1.5 M)-containing medium with chlorpromazine (7 x 10(-5) M, 2.1 x 10(-4) M and 3.5 x 10(-4) M) the hypertonic cold shock was inhibited, the protective effect of the amphipate being less pronounced at its increasing concentrations. After cooling of cells under conditions of moderate hypertonicity (0.3-0.6 M NaCl) no modifying effect of chlorpromazine on the sensitivity of erythrocytes to the temperature decrease from 37 degrees C down to 0 degrees C was manifested. However, under iso- and hypertonic conditions chlorpromazine used at 2.1 x 10(-4) M and 3.5 x 10(-4) M stimulated the cold shock development in erythrocytes. A sharp increase in the medium tonicity (up to 1.8-3.0 M and higher) the cells underwent isothermal hemolysis which was more expressed at 0 degrees C than at 37 degrees C. These data suggest that chlorpromazine significantly activates the hemolytic process at low temperatures.

[Mechanism of erythrocyte cryohemolysis, induced by cationic amphipaths: synergism of induction of the "discocyte-stomatocyte III" transition due to chlorpromazine and medium tonicity]. / Mekhanizm kriogemoliza éritrotsitov, indutsirovannogo kationnymi amfipatami: sinergizm induktsii perekhoda "diskotsit-stomatotsit III" pri deistvii khlorpromazina a tonichnosti sredy.

It is determined that chlorpromazine, a cationic amphipath usually protecting erythrocytes under conditions of hypertonic cryohemolysis is an efficient inductor of the cell lysis in case of cooling in media with tonicity close to the physiological (the isotonic cryohemolysis). Both chlorpromazine and tonicity of the medium influence the alterations in the state of cells, which is confirmed by synergy of the "discocyte-stomatocyte III" transition induction. The above process may be considered as a critical stage of structural modification of erythrocytes. Transition through this stage coincides with appearance of sensitivity to cooling in cells.

[Modifying effect of concanavalin A and diamide on erythrocyte sensitivity to cold shock]. / Modifitsiruiushchii éffekt konkanavalina A i diamida na chuvstvitel'nost' éritrotsitov k kholodovomu shoku.

The temperature (0 degrees C and 37 degrees C) and the medium tonicity (0.15-1.20 M NaCl) were shown to affect erythrocyte agglutination by concanavalin A. Treatment of cells with lectin caused no significant decrease in the erythrocyte hemolysis upon cooling. Diamide, unlike concanavalin A used at concentrations above 2.0 M decreases the cell sensitivity to the cold shock. The changes in the erythrocyte susceptibility to cooling within the temperature range of 37-0 degrees C correlate with changes in the electrophoretic spectrum of membrane proteins. The progressive decrease in the spectrin bands intensity with a simultaneous formation of high molecular weight protein aggregates not included in the gel composition was observed after diamide treatment. The diamide effect depends on the medium tonicity, at which the treatment was performed, being especially well pronounced in hypertonic media with 0.8-1.2 M NaCl concentrations, the maximal spectrin aggregation being observed under these conditions. It is suggested that the main factor of the mechanism underlying the erythrocyte hypertonic cold shock is the increase in the association of peripheral cytoskeleton proteins with plasma membrane in osmotically dehydrated cells which limits the ability of lipids to adapt during cooling and results in the stabilization of defects in the membrane structure at low temperatures. Diamide eliminates these unfavourable changes eventually resulting in the dissociation of peripheral proteins from the cytoplasmic surface of the membrane on the protein aggregation.