Efficacy of green tea extract in two exercise models.

Oral administration of green tea extract in a dose of 6 mg/kg twice a day (before and after exercise) over 2 weeks significantly increased swimming times on week 1 and 2 in comparison with control animals receiving water. The 7-day and final exhaustive running in rats was accompanied by a significant decrease in spleen weight and iron serum levels associated with developed reticulocytosis. Administration of green tea extract in a dose of 12 mg/kg once a day (before exercise) for 2 weeks did not affect the duration of the running, but prevented the decrease in serum iron and spleen weight, that, along with a significantly increased concentration of reduced glutathione in erythrocytes, can indicate a normalizing effect of green tea extract on hemopoiesis and stimulating effect on the antioxidant system of erythrocytes.

[Repeated action of hyperbaria on rat blood system].

There are considered reactions of male Wistar rat blood system to repeated action of nitrogen-oxygen hyperbaria (pressure 0.5 MPa, density of gas medium 6 g/l, pO2 = 0.02-0.03 MPa). Rats were placed into a barochamber for 5 h 24, 72, and 120 h after the first exposition (control in air without the increased pressure). Parameters of red blood were studied and the general state of the animals was estimated. It has been established that after the first hyperbaria séance the stress-reaction develops in rats with all objective stress parameters (level of corticosteroids and content of ascorbic acid in adrenals). At repeated exposure after 24 h the almost complete normalization of all stress parameters was observed, except for the increased hemoglobin content in plasma as a result of impair of permeability of erythrocytic membranes. After repeated actions 72 and 120 h later, the stress parameters manifested again. After exposure 120 h later, the general state of animals was sharply deteriorated they did not move in the "open" field, could not be hold on a horizontal bar, and mainly were lying. The performed control with the immobilization stress showed that after the initial stress-reaction the rats were recovered completely and at repeated exposures no changes were observed in the blood system and in the general state of the animals. We belive that the hyperbaria-produced stress is connected with difficult breathing under pressure. Thereby, the repeated action of hyperbaria is a harmful factor and habituation to it does not occur.

[The effect of antioxidants on erythrocytes in rats during an exhaustive run].

The run of trained rats until exhaustion affected changes of red-ox balance in red blood cells (RBC) and deteriorated the acid stability of RBC. The oral administration of quercetin, 20 mg/kg, caused expansion of oxidative stress in RBC and a significant decrease in RBC acid stability. Pro-oxidant activity of quercetin could contribute accelerated intravascular hemolysis. It was accompanied by a significant reticulocytosis compared with a control group of rats no fed on antioxidant but exposed to run. Green tea extract (GTE) oral administration, 12 mg/kg, resulted in preventing oxidative stress in RBC, increasing in acid stability of RBC and reducing reticulocytosis. Thus, prooxidant activity of quercetin and the high antioxidant efficacy of GTE are indicative of the advantages of the complex preparations containing several antioxidant compounds. Such complex preparations may counteract an oxidative stress and save mechanical stability of erythrocytes under exhausted run.

[Hyperbaria and stress].

Causes of the appearance of stress-reaction at action of hyperbaira on the organism were studied on rats. It has been established that at the 5-h action of gas mixtures (oxygen-nitrogen and oxygen-argon) under pressure 0.35 and 0.5 MPa and partial pressure of oxygen 0.02-0.03 MPa in the chamber of the volume of 300 1 there is obviously manifested stress confirmed by the corresponding markers. The appearance of stress was connected with the gas mixture density that amounts to 6 g/l, which interferes with respiration mechanically. Use of helium at the same pressure of the gas mixture did not cause stress, as its pressure did not exceed the normal air density. On the other hand, use for respiratory mixtures of elegas (SF6) with density of 6 g/l at the normal pressure produced obvious stress. No difference was revealed in action of nitrogen, argon or elegas at equal density. Thus, use of high pressures needs light gases (helium, hydrogen, neon) that have low density.

[Changes of gas exchange parameters and of functional-biochemical properties of erythrocytes in dynamics of experimental anemia in rats].

In experiments on Wistar male rats, on a specially constructed computer installation, O2 consumption by the animals in comparison with changes of hematological, biochemical, and rheological blood properties is studied after anemization--acute bloodletting (12-15% of the total blood mass). An increase of the O2 consumption by the organism and tissues by 18-28% has been revealed for the first 7 days after the bloodletting, in spite of a pronounced decrease of hematocrit, and of the amount of erythrocytes and hemoglobin in peripheral blood by 20-25% of the initial level. There was a 5-10-fold increase of the content of immature erythrocyte forms--reticulocytes and a progressive rise of cell acidic resistance, which is characteristic of young erythrocyte forms. An increase of O2 consumption at a decrease of the blood oxygen capacity (a low hemoglobin level) seems to be due to the more efficient transport and yield of O2 to tissues. At the 3rd 7th day after the bloodletting, activity of Na,K-ATPase has been shown to increase by 60% and 20%, respectively. Analysis of the erythrocyte rheological properties has shown that the maximal firmness of aggregates (Uq) and the aggregation rate (1/T) decrease progressively beginning from 3 days after the bloodletting; index of deformability (I(max)) turned out to be elevated by 7-11%, probably due to an increase of the cell membrane elasticity. The conclusion is made that changes of erythrocyte rheological properties are interconnected with changes of the Na,K-ATPase activity and are directed to optimization of blood circulation in large vessels and the capillary network.

[Changes of physiological and biochemical characteristics of rat erythrocytes after blood loss].

In experiments of Wistar male rats, changes are studied of erythrocyte hematological, biochemical (activitities of transport ATPases), and rheological properties (capability for aggregation and deformability) 7 days after bloodletting of 12-15 % of the total blood mass. It has been shown that alongside with an elevation of erythrocyte volume and of the number of immature cells - reticulocytes, there was a statistically significant increase of Na,K-ATPase and Ca-ATPase activities in the whole erythrocytes and their membrane preparations - ghosts, the increment of activity in the case of Na,K-ATPase being essentially higher in the whole cells. This indicates the appearance of an enzyme activator inside the erythrocytes. There are also revealed a decrease of firmness of erythrocyte aggregates, a deceleration of spontaneous aggregation, and an increase of index of erythrocyte deformability. The conclusion is made that changes of erythrocyte rheological properties are interconnected with changes of the Na,K-ATPase activity and are directed to optimization of blood circulation in large vessels and capillary network.

[Molecular mechanisms of stress].

Data on molecular mechanisms of stress are presented (appearance of stress-proteins in the blood, as well as products of peroxidation products of lipids, and changes of the cell ion balance in stress). Particular accent was made on appearance of endogenous inhibiting agents in the blood: Na+,K+-ATPase, in response to extremal factor actions inducing stress.

Rheologic properties of mammalian erythrocytes: relationship to transport ATPases.

Rheologic properties of erythrocytes and activities of their Ca(2+)-ATPase and Na+, K(+)-ATPase were analyzed together with standard erythrocyte values in seven mammalian species (man, rat, mouse, rabbit, hamster, guinea pig and dog). The number of erythrocytes in the blood of animals investigated correlated inversely with the mean cell volume (MCV) (r = -0.936, P = 0.002) and the mean cell hemoglobin content (MCH) (r = -0.923, P = 0.003). MCV and MCH also showed a high direct correlation with each other (r = 0.907, P = 0.005). The maximal erythrocyte deformability (DImax) measured with ektacytometry was inversely proportional to the MCV and MCH (r = -0.854, P = 0.014, and r = -0.940, P < 0.002, respectively). The MCV was also linearly related with the Na+, K(+)-ATPase activity (r = -0.791, P = 0.034). The major parameters of osmoscan (O' and Omax) and their derivatives (O'-Omin, Omax-Omin) were shown to be in a direct correlation with each other and with the activity of Na+, K(+)-ATPase in the whole erythrocytes except for the rabbit Na+, K(+)-ATPase. The activity of Ca(2+)-ATPase in the whole erythrocytes significantly correlated only with the O' and O'-Omin values. Thus, the activities of transport ATPases in mammalian red cells seem to be adjusted to the level required to maintain particular rheologic properties of the cells of one or other species.

Species variability of erythrocyte transport ATPases in mammals.

Na+, K(+)-ATPase, and Ca(2+)-ATPase in whole erythrocytes from five species of mammals (rat, mouse, guinea pig, golden hamster, rabbit) after cell treatment with Tween 20 (7.5 mg/ml) varied over a wide range: from 3.0 +/- 0.9 mumol Pi/hr/ml cells in rabbit to 27.3 +/- 4.9 mumol Pi/hr/ml cells in mouse for Na+, K(+)-ATPase and from 8.0 +/- 1.6 mumol Pi/hr/ml cells in hamster to 47.2 +/- 4.9 mumol Pi/hr/ml cells in mouse for Ca(2+)-ATPase. Differences were less pronounced in red cell ghosts. Fatty acid and phospholipid compositions of erythrocyte membranes were similar for all species. Nevertheless, the activity of Ca(2+)-ATPase in ghosts significantly correlated (r = -0.884) with the ratio of PC + SM/PE + PS in red cell membranes. Rabbit membranes had the lowest content of arachidonate. Rat hemolysate activated Na+, K(+)-ATPase in the ghosts from the animals of any species investigated, whereas the enzyme activation by the homohemolysate was characteristic only of the rat, mouse, and guinea pig ghosts. The data obtained suggest that there are differences in both activity and intracellular control of transport ATPase in erythrocytes of different mammals.

[Effect of albumin on the Na, K-ATPase activity in the rat erythrocytes during immobilization stress]. / Vliianie al'bumina na aktivnost' Na, K-ATFazy éritrotsitov krys v usloviiakh immobilizatsionnogo stressa.

Immobilisation stress (IMS) led to a 42% decrease in erythrocyte Na, K-ATPase activity in rats. Pre-treatment of the "stressed" erythrocytes with human serum albumin (HSA) and 1-day exposition of the HSA prior to the IMS led to stabilising of enzyme activity at the control level. Absence of inhibiting effect of non-protein supernatants of the blood plasma of stressed rats on enzyme activity of normal erythrocytes was shown in presence of the HSA both in vitro and in vivo. The mechanism of the HSA protective effect on the Na,K-ATPase activity of erythrocytes in the IMS, is discussed.

[Suppression of the sexual cycle in rodents]. / Podavlenie polovogo tsikla u gryzunov.

Protracted per os introduction of "Anaster" preparation, the derivative of carbon acids causes inhibitory effect to sexual activity of female rodents (rats, mice, hamsters) in particular, to the dynamics of sexual cycles and as a result sharp decrease of reproductive function. "Anaster" has no remote after-effects and the stop of its taking leads to quick and complete restoration of sexual cycles.

[The activity of erythrocyte membrane enzymes in different stressor exposures]. / Aktivnost' membrannykh fermentov éritrotsitov pri razlichnykh stressornykh vozdeistviiakh.

The decrease in activity of acetylcholinesterase and Na,K-ATPase of erythrocyte membranes was found to be the result of stress effects. These decrease may be concerned with the changes of ratio of various erythrocyte population the appearance in blood "old" cells having 1.8-2.0 times lower activity of membrane-bound enzymes. The specific digoxin-like inhibitors of Na,K-ATPase was revealed in blood, which also contribute to the inhibition of the enzyme activity. For correct interpretation of the reason of changes in activity of erythrocyte membrane enzymes in stress conditions the complex of physiological changes on the level of the whole organisms has to be taken into account.

[The activity of transport ATPases and the characteristics of the protein-lipid composition of the membranes of anuclear erythrocytes in a number of mammals]. / Aktivnost' transportnykh ATFaz i nekotorye kharakteristiki belkovo-lipidnogo sostava membran bez''iadernykh éritrotsitov riada mlekopitaiushchikh.

The activity of Na,K-ATPase and Ca-ATPase of the intact erythrocytes and their membrane preparations and also fatty acid, phospholipid and protein content of erythrocyte membrane of guinea pig, mouse, rabbit and hamster have been examined. The activity of Na,K- and Ca-ATPase in intact erythrocytes varies significantly among different species while the level of activity of these enzymes in their membrane preparations differs slightly. Together with the results of investigations of chemical composition of the erythrocyte membrane of these species which show the principal homogeneity of their fatty acid, phospholipid and protein composition, these data indicate the existence of the system of intracellular modulators, that maintain the activity of these enzymes on the species specific level.

[The dynamics and mechanism of changes in the erythrocyte Na, K-ATPase activity of rats under the action of different types of stressors]. / Dinamika i mekhanizm izmeneniia aktivnosti Na, K-ATFazy éritrotsitov krys pri deistvii stressorov razlichnoi prirody.

The rat erythrocytes' Na, K-ATPase activity was found to drop under the effects of five various stresses: immobilisation, hypothermia, hyperoxia, physical strain, and physical strain against the background of fasting. An endogenous digoxin-like inhibiting agent(s) acting on the Na, K-ATPase seems to appear in the blood plasma of the animals under stress. The suggestion is corroborated by the fact that albumin-less supernatants of the stressed rats' blood plasma are able to inhibit the Na, K-ATPase in the erythrocytes of the control animals.