Adaptation to altitude hypoxia limits lipid peroxidation during inflammation and stress

Preadaptation of rats to altitude hypoxia results in reduced activation of lipid peroxidation during subsequent stress, inflammation, or both, as compared to hypoxiaunadapted animals, with the result that secondary changes in organs and tissues of adapted rats are much less pronounced and conditions are created for alleviating the acute inflammation and the stress reaction. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 119, N ^o 6, pp. 590–593, June, 1995 Presented by E. D. Gol'dberg, Member of the Russian Academy of Medical Sciences     

Time course of lipid peroxidation during adaptation of men to novel ecological conditions

Changes in the intensity of lipid peroxidation and serum activities of superoxide dismutase and catalase were similar after 18-month adaptation to new ecological conditions of soldiers serving in two different regions. All values increased and reached the maximum by the 6th month, after which they stabilized; catalase activity decreased after 6 months. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 124, No. 12, pp. 678–682, December, 1997     

Structural changes in dog liver during adaptation to high altitude

Vascular and tissue changes in the livers of dogs living on an altitude of 3200 m above sea level for various periods were studied by histological, morphometric, and electromicroscopic methods. Destructive changes were observed in hepatocytes after a month of exposure, which were due mainly to impaired hepatic microcirculation and increased from the center to the periphery of hepatic acinus. Ultrastructural changes occurred predominantly in the energy-producing and protein-synthesizing systems of hepatocytes. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 123, No. 6, pp. 714–717, June, 1997     

Dynamics of aseptic inflammation against the background of α-tocopherol

Administration of α-tocopherol before the induction of inflammation reduces the vascular response and inhibits the leukocyte phase, which limits the development of secondary alterations in tissues. During the reparative period fibroblast proliferation is suppressed and differentiation is accelerated, whereas the synthetic activity is lowered. As a result, the formation of the fibroblast capsule is slowed down. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 118, N ^o 9, pp. 249–251, September, 1994 Presented by E. D. Gol'dberg, Member of the Russian Academy of Medical Sciences     

Opposite effects of adaptation to short-term stress and adaptation to periodic hypoxia on Na,K-ATPase activity in liver plasma membranes

Na,K-ATPase activity is shown to be lowered more than twice 2 hours after emotional pain stress in comparison with the initial level, remaining practically unchanged during the subsequent 24 hours. Adaptation to repeated stress results in a 50% activation of Na,K-ATPase. A protective effect is demonstrated in long-term stress against the background of preadaptation. Adaptation to periodic hypoxia inhibits liver Na,K-ATPase to the same extent as does acute stress. Against the background of preadaptation to periodic hypoxia, stress does not aggravate the drop of Na,K-ATPase activity. Adaptation to stress inhibits accumulation of products ofin vitro-induced lipid peroxidation in the heart 1.4-fold and does not affect it in the liver, whereas adaptation to hypoxia sharply accelerates the accumulation of oxidized products in both organs, which probably explains the activation of liver Na,K-ATPase in adaptation to stress and its inhibition in adaptation to hypoxia. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 121, No. 4, pp. 383–386, April, 1996 Presented by G. N. Kryzhanovskii, Member of the Russian Academy of Medical Sciences     

Adaptation to periodic high-altitude hypoxia inhibits baroreflex vagal bradycardia in rats

A 3-week course of adaptation to high-altitude hypoxia (4500 m above sea level) inhibited baroreflex avagal bradycardia induced by a rapid rise of systemic blood pressure in conscious rats. Bradycardic responses to electrical stimulation of peripheral end of the right vagus nerve and methacholine (M₂ muscarinic receptor agonist) in hypoxia-adapted rats did not differ from the control. It is concluded that hypoxia inhibits baroreflex vagal bradycardia by acting on a central element of the baroreceptor reflex arch Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 129, No. 4, pp. 386–389, April, 2000     

Adaptation to hypoxia,unlike adaptation to stress,fails to protect the isolated heart from reperfusion after total ischemia (An NMR study)

Effects of adaptation to hypoxia on the contractility of isolated rat hearts and on their levels of ATP and inorganic phosphate after total ischemia were evaluated. This adaptation failed to render the cardiac energy-supplying system more resistant to postischemic reperfusion and thus did not accelerate the restoration of cardiac contractility after ischemia. The results of adaptation to hypoxia were then compared with those of adaptation to stress, which had been shown to bring about a marked increase in cardiac resistance to postischemic reperfusion. It is concluded that the profound differences noted between the cardioprotective effects of these two forms of adaptation are due to a much greater accumulation of stabilizing proteins from the HSP70 family during adaptation to stress. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 120, N ^o 11, pp. 481–484, November, 1995 Presented by N. R. Paleev, Member of the Russian Academy of Medical Sciences     

Effects of adaptation to hypoxia on cytochrome levels in the brain and liver of rats

After a prolonged (for 30 days) adaptation of rats to intermittent hypoxia, their brains contained lowered levels of mitochondrial cytochromes, despite an increase in the number of mitochondria in the brain tissue mass, along with similar levels of high-energy compounds and more protein as compaired to the brains of unadapted controls. A mitochondrial population with novel properties presumably emerged in the brain. These effects were all more strongly marked in rats with an initially low resistance to hypoxia. In the liver of hypoxiaadapted animals, unlike in their brain, cytochrome levels in the mitochondrial and microsomal redox chains were lowered and the biogenesis of mitochondria was much less intensive. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 120, N ^o 12, pp. 576–579, December, 1995     

On the erythron response to inflammation and its mechanisms

Using the mouse model of acute infectious peritonitis caused byEscherichia coli, it is shown that the development of inflammation is accompanied by increases in the number of erythrokaryocytes, erythroid colony-forming units, and erythroid hematopoietic islets in the bone marrow and by rises in the activities of supernatants of cultured stimulated adherent and nonadherent myelokaryocytes and of peripheral blood. The results of this study indicate that a characteristic, feature of acute inflammation is strong activation of erythropoiesis with the development of hyperplasia of the erythroid marrow. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 120, N ^o 10, pp. 382–384, October, 1995     

Adaptation to periodic hypoxia restricts subdural hemorrhage during audiogenic epileptic seizures in rats

Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 116, N ^o 12, pp. 572–574, December, 1993     

Immunological responses during the organism's adaptation to a dosed thermal factor

Overheating of mice over the course of 10 and 20 days suppresses the proliferative activity of splenic cells in response to stimulation with phytohemagglutinin, concanavalin A, lipopolysaccharide, pokeweed mitogen, and alloantigens. The number of antibody-producing cells in the spleen drops on day 5 of overheating and is still low on days 10–20. Forty days after the start of overheating the functional activity of lymphocytes is restored. Overheating of animals does not change the colony-forming activity of hemopoietic stem cells. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 117, N ^o 5, pp. 502–504, May, 1994 Presented by N. A. Vasil'ev, Member of the Russian Academy of Medical Sciences     

Individual resistance of the organism and nerve cell to hypoxia

The correlation between the pattern of a neuron's reaction to acute hypoxia and individual resistance to oxygen deficit is studied on ratsin vivo as well as on surviving slices of their cerebellumin vitro. According to the survival time in a pressure chamber simulating an altitude of 11 km all the rats were divided into groups of high resistance, medium resistance, and low resistance to hypoxia. Survival time was 4.2 times longer in the high resistance group than in the low resistance group. In the cerebellar slices of high resistance animals 61.5% high-resistance neurons and 38.5% low-resistance neurons were recorded. On the other hand, in the high resistance animals the percentage of high-resistance neurons and low-resistance neurons was 31.2 and 68.8, respectively. The period of hypoxia development was 4.32 times longer in the high-resistance neurons as compared to low-resistance neurons. It is speculated that individual differences in the resistance to O₂ deficit are of a hereditary nature and manifest themselves not only on the level of the whole organism, but also in the individual nerve cell. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 118, N ^o 11, pp. 454–457, November, 1994     

Reactivity of the conjunctival microcirculatory bed in students from various regions of the world as an indicator of adaptation of the organism

Microcirculatory vessels of the eyeball conjunctiva were examined during exercise in students from Asia, Africa, and Latin America. The reactivity of microvessels was found to be increased at the early stages of adaptation, which indicates a high-level compensatory potential of the organism. An appreciable reduction of microvessel reactivity after 1 to 2 years of university studies indicates a decrease of the compensatory potential in this period of adaptation. After 4–5 years of studies the reactivity of the microvessels is virtually the same in foreign and Russian students, this indicating the formation of a stable phase of adaptation. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 119, N ^o 4, pp. 423–426, April, 1995 Presented by N. A. Agadzhanyan, Member of the Russian Academy of Medical Sciences     

Effects of adaptation to periodic hypoxia on kinetic parameters of respiratory chain enzymes in rat brain

A study of kinetic parameters of brain respiratory enzymes revealed that the maximal velocity and the Michaelis apparent constant for NADH-cytochrome C-reductase are significantly lower in low-resistant rats than in rats with a high resistance to hypoxia. Adaptation to periodic hypoxia increases total resistance only in low-resistant rats. It is accompanied by an increase in the values of kinetics parameters for NADH-cytochrome C-reductase and cytochrome oxidase. Kinetic parameters for these enzymes in the brain of high-resistant rats are either unaltered or even decreased. It is suggested that the first enzymatic complex of the respiratory chain is one of the limiting or regulating links in energy metabolism determining the brain's resistance to hypoxia. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 121, N ^o 3, pp. 252–255, March, 1996.