[Radioresistance mechanisms of side population cells in mouse melanoma cell line B16].

As it was shown by us earlier, side population (SP) cells are more resistant to the low-LET radiation than the other part of mouse melanoma B16 cells (Matchuk et al., 2012). The aim of our research was finding some mechanisms of radioresistance, therefore we analyzed SP and nonSP cell cycle distribution, spontaneous and radiation induced DNA double-strand breaks (number of γH2AX foci) and intracellular NO concentration. The results indicate that SP cells have significantly less DNA double-strand breaks after irradiation at dose of 3 Gy than nonSP cells (24.4 vs 40.3, accordingly, P < 0.05 Mann-Whitney Ucriterion). SP cells are more quiescent compared to nonSP G1/G0 fraction is 85 vs 39%, accordingly, P < 0.01 Mann-Whitney U criterion). Most nonSP cells reside in S, G2/M phases (61%), believed to be rather radiosensitive. Thus, the difference of SP and nonSP cells radiosensitivity can be partly explained by peculiarities of cell cycle distribution. NO concentration is 1.5 times higher in SP than nonSP cells (P < 0.05 Mann-Whitney U criterion); since it is known that NO inhibits apoptosis, being one of the mechanisms of genetic stability maintenance, greater number of spontaneous DNA double-strand breaks in SP cells is unsurprising (P < 0.05 Mann-Whitney U criterion). The above-listed results explain considerably the higher resistance of SP cells to the action of low-LET radiation in comparison with other melanoma B16 cells. Further study of this question can become the basis for development of tools to target SP cells and, ultimately, more effective cancer treatment.

[The assessment of biocenosis contamination in the region of radioactive waste storage (RWS) placing and influence of this storage on rodents].

The results of radiative and of chemical monitoring show definite contamination of this zone by 90Sr and toxic metals. The essential local contaminations of geosystems (up to 2.3 x 10(4) Bk/kg of soil) require in environmental condition assessment at biocenosis level. Biotesting found the increase of metallothioneines levels in kidney (up to 15.63 microg/g of tissue) and liver (up to 19.22 microg/g of tissue) of rodents inhabited in the region of RWS placing as compared with the control group (3.51 and 4.44 microg/g of tissue accordingly). Besides, the decrease of total quantity of leucocytes (by 14.5% as compared with the control group) and absolute quantity all forms of them in animal blood were noted. It was assumed the increase of protein--MT is the result of complex influence by ionizing radiation and toxic metals.

[Internal organs as a blood depot during different extreme exposures]. / Vnutrennie organy kak depo krovi pri razlichnykh ékstremal'nykh vozdeistviiakh.

The results of an experimental study of fluctuations in the relative content of blood in 15 internal organs on exposure of the intact organism to the effect of various factors are discussed. A total of 25 experimental series was conducted, with 14 animals used in each series. Four types of regional blood redistribution reactions were distinguished according to the changes in blood filling (in the brain, heart, liver, and other organs of the abdomen and true pelvis). In most cases these reactions are accepted as a sign of mobilization of the dynamic intravascular blood reserve from the large-capacity vessels, mainly of the abdominal organs and organs of the true pelvis, with or without the participation of the liver, and also as a sign of utilization of the "reserve" blood in organs and tissues experiencing functional stress. The results of correlative analysis bear evidence of the reciprocal character of fluctuations in the amount of blood during stress, in the brain, lungs, and heart on the one hand and in the organs of the abdomen and true pelvis on the other, and also testify to the autonomous character of changes in the amount of blood in the liver. The internal organs of the abdomen and true pelvis are not a functionally single vascular region.

[Myocardial blood supply under different degrees of emotional excitation and the pathophysiological characteristics of the mechanisms of its adaptation]. / Krovosnabzhenie miokarda pri razlichnoi stepeni émotsional'nogo vozbuzhdeniia i patofiziologicheskaia kharakteristika nekotorykh mekhanizmov ego adaptatsii.

Emotional stress was stimulated by placing rats in a tight cage (moderate stress) or fixing them rigidly on a bench (marked stress) for 1 hour. In moderate emotional stress, the coronary fraction of cardiac output and effective myocardial blood supply declined considerably. Marked emotional stress caused a similar reduction in the cardiac output coronary fraction, whereas effective myocardial blood supply was not reduced, but, on the contrary, tended to increase. The decrease in coronary fraction was not related to adrenergic effects. Marked emotional stress provoked regional changes in the resistance, microcirculatory and capacity components of the vascular bed, an adaptation to enable effective myocardial blood supply and enhance cardiac activity. It was accompanied with kallikrein-kinin activation.

[Quantitative characteristics of blood redistribution after death by radioactive indication]. / Kolichestvennaia kharakteristika peremeshchenii krovi posle smerti metodom radioaktivnoi indikatsii.

The methods of radioactive detection and external radiometry were used to study the distribution of blood in cats and rats during 24 hours after heart arrest. Labeled albumins (131I) and erythrocytes (51Cr) were used as blood indicators. The animals after death were stored in a horizontal or, in some tests, in vertical position at room temperature. The activity was measured in the horizontal and sagittal planes in strictly defined sites (30 altogether) or by scanning of the entire body within 3-5 min after circulation arrest as well as at 5 and 24 hours. No significant changes in distribution of plasma and erythrocytes during 24 hours postmortem in the horizontal position were shown to occur, while in the vertical position there was an insignificant increase of the blood content in the lower part of the body.

[Regional vascular effects of a decrease in adrenergic activity under conditions of a resting state in animals and during immobilization]. / Regionarnye sosudistye éffekty snizheniia adrenergicheskoi aktivnost' v usloviiakh spokoinogo sostoianiia zhivotnykh i ikh immobilizatsii.

Regional changes of circulation after injection of pirroxan, obsidan and ornid depended on functional state of rats. The differences were significant in systemic hemodynamic and regional changes of resistive, transcapillary exchange and the blood volume function of the circulation.

[Regional changes in circulation in response to stimulation of beta-adrenergic receptors with isoproterenol]. / Regionarnye izmeneniia krovoobrashcheniia pod vliianiem stimuliatsii beta-adrenergicheskikh retseptorov izoproterenolom.

The muscle and adrenal fractions of cardiac output increased after injection of isoproterenol. The relative blood flow increase in skeletal muscles was accompanied with the increase in regional by-pass blood flow. The latter or reduction in the vessel permeability were found in the lungs. The cardiac output fractions decreased in extensive areas of skin, brain, myocardium, internal organs of hepatic portal vein, kidneys, testicles. The signs of the blood flow increase were found in the brain, myocardium, liver. The relative blood volume decreased in the majority of internal organs and tissues while increasing in the liver.

[Regional redistribution of blood during air cooling of unanesthetized rats]. / Regionarnye pereraspredeleniia krovi pri vozdushnom okhlazhdenii nenarkotizirovannykh krys

3-hr exposure to air at +5 degrees C of unrestrained rats evoked a relative reduction of blood volume in vessels of the skin, skeletal muscles, abdominal and pelvic organs (except liver). Increase of the blood volume occurred in the brain, thoracic organs, and in the liver. No significant decrease of the rectal temperature was noticed at that, in spite of cooling of the skin of different parts of the body and tail. Cooling of restrained rats at +5 degrees C during 1 and 3 hrs decreased the rectal temperature. The main direction of the blood redistribution involved its removal from the liver to the deep muscle tissues. At the beginning of the cooling and immediately after self--warming the relative increase of the blood volume was more obvious in the skeletal muscles of the anterior body parts.

[Regional blood filling in hypoxic hypoxia]. / Regionarnoe krovenapolnenie pri gipoksicheskoi gipoksii.

Unanesthetized rats put in the hermetic chamber breathed with a gas mixture containing 10.5% of oxygen in nitrogen during 30 and 60 min (moderate hypoxia), and 3.5% of oxygen in nitrogen for 30 min (severe hypoxia). The circulating blood volume increased in moderate hypoxia but was rather reduced in severe hypoxia. Mobilization of blood from the liver occurred in moderate hypoxia after 30 min, becoming less obvious after 60 min or in severe hypoxia. Redistribution of blood in the myocardium, skeletal muscles of the head and neck occurred in moderate hypoxia. Severe hypoxia led to depression of the regional circulating blod redistribution and the signs of pathological accumulation of the blood in the liver, small intestine, colon and testicles.

[Changes in the systemic and regional circulation responses to immobilization stress in the rat after pharmacological sympathectomy]. / Izmenenie reaktsii sistemnogo i regionarnogo krovoobrashcheniia na fiksatsionnyi stress u krys pri farmakologicheskoi desimpatizatsii.

A preliminary pharmacological desympathization (pirroxan, obzidan, ornid) decreased blood pressure, heart rate, cardiac output, and increased total vascular resistance in immobilized rats. The fraction of cardiac output decreased in lung (bronchial blood flow), liver and myocardium and increased in other organs and tissues. Relative blood supply increased in expansive regions of the skin, muscles and splanchnic organs but decreased in the liver. Opposite changes of transcapillary permeability were found in vascular regions of the skin and skeletal muscles as well as in splanchnic organs.

[Regional redistributions of the blood in high and low small intestine obstruction]. / Regionarnye pereraspredeleniia krovi pri vysokoi i nizkoi tonkokishechnoi neprokhodimosti.

In the experimental model of high and low obstruction of the small intestine during 24 hours the authors observed considerable shifts in electrolytic blood content. Total amount of circulating blood, compared with control (laparotomy), was not changed. These data allowed a new consideration of the entity of the pathological syndrome in intestinal obstruction.

[Regional blood redistributions after experimental laparotomy]. / Regionarnye pereraspredeleniia krovi posle laparotomii v éksperimente.

The authors studied regional redistribution of the blood in the experiments on 12 white male rats adapted to the experimental conditions. There were no postoperative complications in the laparotomy model. The main direction of the postoperative regional blood redistributions has been considered as one of the typical redistribution reactions associated with the mobilization of the intravascular blood reserve and its use in the organs with an intense function.