Tissue breathing and topology of rats thymocytes surface under acute total γ-irradiation. / TKANEVOE DYKhANIE I TOPOLOGIIa POVERKhNOSTI TIMOTsITOV KRYS PRI ODNOKRATNOM OBShchEM γ-OBLUChENII.

OBJECTIVE: Assessment of the effect of single total γ irradiation to the parameters of mitochondrial oxidation and the topology of the thymocyte surface. MATERIALS AND METHODS: The study was performed in sexually mature white outbreeding male rats divided into three groups: two experimental and one control. The states of energy metabolism were determined by the rate of oxygen consumption by the thymus tissues on endogenous substrates at the presence of 2,4 dinitrophenol, uncoupler of a tissue breathing (TB) and oxidative phosphorylation (OP) after a single total γ irradiation at a dose of 1.0 Gy at 3, 10, 40 and 60 days. The topology of thymus cells was assessed using atomic force microscopy (AFM) and scanning electron microscopy (SEM). RESULTS: On the 3rd and 10th days after total gamma irradiation at a dose of 1.0 Gy, a significant decrease in respira tory activity was determined in thymus tissues on endogenous substrates. Simultaneously, on the 3rd day, pro nounced changes in the morphological parameters of thymocytes (height, volume, area of contact with the sub strate) and the topology of their surface were also observed. On the 10th day after irradiation, most of the morpho logical parameters of thymocytes, except for their volume, were characterized by restoration to normal. In the long term (on the 30th and 60th days after exposure), a gradual but not complete recovery of the respiratory activity of thymocytes was observed, accompanied by an increase in the degree of dissociation of TD and OP. CONCLUSIONS: The obtained data reflect and refine mechanisms of post radiation repair of lymphopoiesis, showing the presence of conjugated changes in the parameters of aerobic energy metabolism of thymocytes, morphology and topology of their surface. The synchronism of changes in the parameters under study is a reflection of the state of the cytoskeleton, the functional activity of which largely depends on the level and efficiency of mitochondrial oxidation.

Low doses of hyperbaric oxygenation effectively decrease the size of necrotic zone in rats with experimental myocardial infarction.

We studied the effect of a single session of hyperbaric oxygenation on the size of risk, ischemic, and necrotic zones in rat myocardium after irreversible occlusion of the coronary artery and excessive oxygen pressure of 0.02 and 0.1 MPa. Myocardium infarction was reproduced by ligation of the left coronary artery. The size of the risk, ischemic, and necrotic zones was planimetrically evaluated. Hyperbaric oxygenation (60-min session) was performed 3 h after artery occlusion at excessive oxygen pressure of 0.02 and 0.1 MPa. In rats not exposed to hyperbaric oxygenation, the risk zone median was 31.7% of the left ventricle weight, while after the session it did not exceed 25%. In spontaneous course of myocardium infarction, the ischemia to necrosis zone ratio was 1.7:1, while under conditions of hyperbaric oxygenation at oxygen pressure of 0.1 and 0.02 MPa, the these values were 0.6:1 and 2:1, respectively. Excessive oxygen pressure of 0.02 mPa is better than traditionally used 0.1 MPa, because it promotes redistribution of the ischemic and necrotic areas in the risk zone: the area of necrotic zone decreased at the expense of the ischemic zone. Hyperbaric oxygenation produces a positive effect on the myocardium under conditions of total occlusion of the coronary artery.

[Surface architectonics and cytoskeleton state of different age rats' thymocytes exposed to peroxynitrite].

To reveal the role of aging in the changes of immune system cells response to proinflammatory (oxidizing) agent we have studied peroxynitrite (30 microM) influence on the cell surface layer structure of different age rats' thymocytes. In the absence of proinflammatory agent, there were no significant changes in morphological and topological parameters of thymocytes from the rats at 3 and 8 months of age. According to atomic force microscopy data, peroxynitrite stimulates actin cytoskeleton structures assembly in thymocytes from 3-month rats but inhibits it in cells from 8-month rats. Obtained results make clear the difference between the immune system responses in inflammatory processes of young and old organisms.

[The influence of vitamins A, E, C upon the respiration activity of the spleen lymphocytes ].

In the experiment on albino male mongrel rats some parameters of oxidative phosphorylation of spleen slices were studied after the animals were fed the antioxidant complex of vitamins E, A, and C. The stimulation of oxygen consumption rate and of tissue respiration of spleen was observed with endogenous substrates, and after exogenous substrates (succinate and glutamate) were added. After the ingestion of vegetable oil the uncoupling of oxidative phosphorylation was observed. The perspectives of alimentary and medicine immunocorrection by the influence upon the mitochondrial oxidation system of cell immune competence organ discussed.

[The estimation of the antioxidant activity of lacrimal fluid].

A new approach for evaluation of the antioxidant activity of lacrimal fluid (LF) has been proposed. It is based on the method of the analysis of the antioxidant activity of blood and superoxide dismutase activity (Sirota T.V., 1999). In the present work, the method has been first used for examining the antioxidant properties of LF, which is estimated by the ability of LF to inhibit or activate the rate of adrenaline autooxidation in an alkaline medium. The method does not require expensive reagents and equipment; it is simple, accessible, and highly informative. LF of practically healthy people possesses a marked antioxidant activity. In people with symptoms of acute respiratory virus infections, complete loss of the antioxidant activity of LF and the appearance of prooxidant activity were observed. In people taking polyvitamins in prophylactic doses, a significant increase in the antioxidant activity of LF was observed. This method may be applicable in ophthalmology for the diagnosis, control of treatment efficiency, and prognosis of eye diseases.

[Characteristics of mitochondria and myocardium ultrastructure of rats following chronic incorporation of cesium radionuclides 137 Cs]. / Kharakteristika mitokhondrii i ul'trastruktura miokarda krys v usloviiakh prodolzhitel'noi inkorporatsii radionuklidov 137 Cs.

Ultrastructure, tissue respiration and oxidative phosphorilation were studies in the myocardium of animals after chronic natural irradiation by 137Cs in quantities that can in reality threaten population of radionuclide-polluted regions. Decline in the respiratory activity of the myocardium and ultrastructural disorders can be attributed to the effects of ions of radioactive Cs which is also a potassium antagonist. A hypothesis has been put forward according to which cesium blocks potassium channels in mitochondria and thus changes the volume and configuration of internal mitochondrial membranes, and impacts the respiratory processes. In the opinion of the authors, these changes characterize the mitochondrial phase of apoptosis which, in the event of chronic exposure to radionuclides, is a compensatory-adaptive mechanism eliminating the least immutable subpopulation of cardiomyocites.

[Mitochondrial oxidation and ultrastructure of the myocardium on a background of incorporation of cesium radionuclides]. / Mitokhondrial'noe okislenie i ul'trastruktura miokarda pri inkorporatsii radionuklidov tseziia.

Parameters of the mitochondrial oxidation and ultrastructure of the myocardium in white rats were studied on a background of consumption of food supplemented with 137Cs at 60 or 600 Bq/kg (calculated doses were 1.5 and 15 microGy, respectively). The observed stimulation of the respiratory activity in myocardial samples cultivated on endogenous and several exogenous substrates was found to reduce the effectiveness of energy production by dissociation of oxidative phosphorylation and disruption of macroerg deposition in the form of creatine phosphate. Ultrastructural findings included swelling of mitochondria, matrix clarification, partial reduction of the number of crists, and myeline-like bodies in the matrix. Observed were high nucleus structural polymorphism with extension of the perinuclear space, spotted distribution of chromatin, and modification of the myofibril structure. These morphofunctional changes can be considered as reflection of apoptosis associated with activation of peroxidation.

[Effects of hypokinesia of different duration on electrolyte contents in muscle tissue of rats]. / Vliianie gipokinezii razlichnoi prodolzhitel'nosti na soderzhanie élektrolitov v myshechnoi tkani krys.

The study has demonstrated a significant increase in blood levels of potassium on Day 3 of hypokinesia. Sodium content and the sum of two ions were decreased on Day 3 and increased on Day 10 of the exposure. Significant changes in the calf muscles (musculus gastrocnemius), i.e. decreased potassium and increased sodium concentrations, were observed on Days 10, 30, 45, 70, 90, and 140. The total content of potassium and sodium ions remained reduced. Analysis of parameters characterising the ion gradients points to lowered activity of Na-K-dependent ATP-ase, fewer number of ion-binding groups of tissue anions. In myocardium, these shifts were less pronounced and included an insignificant loss of potassium ions and gain in sodium ions the gradient of which was most significant on Days 10, 30, and 45. The general trend of changes in the ion balance implies some unified mechanisms of the hypokinesia effects on the muscular tissue, associated with the disorders in energy metabolism, change in hormonal status, and activation of catabolic processes in immobilised body giving rise to deconditioning and asthenization.

[Characteristics of the pool of blood free amino acids of rats during extended hypokinesis]. / Kharakteristika pula svobodnykh aminokislot plazmy krovi krys pri dlitel'noi gipokinezii.

23 free amino acids (AA) were analyzed in blood plasma of rats during 70- and 140-day hypokinesia (HK). The total content of free AA after 70-day HK was found to level down by one third as a result of reduction of the majority of AA excluding glutamate, glutamine, and cystine, the concentrations of which exceeded controls by 21.8%, 4.6%, and 6.3%, respectively. The period of HK extended up to 140 days, the sum of free AA remained lowered; however, glutamate and cystine levels were higher than in control by 10.3% and 183.2%, respectively. The causes for changes of absolute (mM/l) and relative (% in the pool) concentrations of individual AA and their metabolic groups with account for specificity of neuroendocrine regulation and energy metabolism in the skeletal muscles, myocardium, liver, kidneys in dehydrated organism are discussed.

[Blood plasma protein fractions in rats during hypokinesia of various durations]. / Belkovye fraktsii plazmy krovi u krys pri gipokinezii razlichnoi prodolzhitelnosti.

The studies indicated that the total content of blood plasma protein in the rats decreases on Days 3, 10 and 30 of hypokinesia and returns to norm on Days 70-140. Albumen concentration increases on Day 3, decreases on Day 10 and normalizes during subsequent days of hypokinesia. The level of alpha-1 globulins reduces on Days 3, 10, increases on Days 30, 70 and normalizes on Days 140 of an exposure. Beta-globulin content decreases on Days 3, 10, 70 and 140 of hypokinesia and level of gamma-globulins also reduces on Days 3 and 30 of hypokinesia and exceeds control values on Days 10, 70 and 140 of immobilization. Since metabolism of the main mass of blood plasma proteins is under hormonal control and their synthesis occurs predominantly in the cells of liver and lymphoid system the data obtained are discussed with regard to the peculiarities of hormonal balance and energy metabolism of the immobilized body.

[Energy metabolism in the kidneys after hypokinesia of varying duration]. / Energeticheskii obmen v pochkakh pri deistvii na organizm gipokinezii razlichnoi dlitel'nosti.

This paper presents data suggesting that tissue homogenates can be used to assess mitochondrial oxidation. The effect of hypokinesia of various duration on tissue respiration and oxidative phosphorylation of rat kidneys was investigated for the first time. It was found that 3-day hypokinesia led to a decrease of tissue respiration due to a lower contribution of endogenous fatty acids; 10-day hypokinesia caused activation of tissue respiration on endogenous and exogenous pyridine and flavoprotein-dependent substrates; 30-, 70- and 140-day hypokinesia brought about changes in energy formation at the expense of inhibition of respiratory activity of preparations and uncoupling of oxidative phosphorylation. Mechanisms of the above disturbances in energy metabolism reactions of kidneys are discussed.

[Energy metabolism in muscle tissue during hypokinesia of various durations]. / Sostoianie énergeticheskogo obmena myshechnoi tkani pri gipokinezii razlichnoi dlitel'nosti.

The state of energy metabolism in skeletal muscles and myocardium of albino rats was studied under long hypokinesia. It is established that on the 30th-70th days of hypokinesia endogenic fatty acids, whose oxidation promotes the uncoupling of oxidative phosphorylation and inhibition of the creatine phosphokinase reaction, are the main substrate of energy metabolism. In blood there occurs hyperlipemia and a decrease in the glucose content. A further immobilization results in predominance of succinate-dependent respiration, in blood there occurs a certain decrease in lipemia, normalization of the glucose level and an increase in the urea content.