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Biomedical subjects

V F Makeeva

Publications and source records attributed to V F Makeeva.

32 records · Page 2Linked to original sources
PubMedDate not supplied

[Nucleic acids of the lymphoid cells of the pregnant rat subjected to space flight and its progeny].

The space flight effect on the synthesis of nucleic acids in spleen lymphocytes in pregnant rats and their offspring was investigated. In addition to the inhibition of the DNA replicative function previously detected in males, activation of RNA synthesis was seen in the pregnant females. Such changes did not develop in the synchronous mockup controls. The 30-day and 100-day old pups of the rats flown in space during the last third of their pregnancy showed no changes in the DNA replicative function. The 100-day old animals displayed only a slight, when compared to the vivarium controls, decline of RNA synthesis which was produced by concomitant factors rather than by microgravity per se. It is supposed that microgravity-induced activation of RNA synthesis in spleen lymphocytes of pregnant rats is associated with the involvement of these cells in adaptive trophic processes that are to maintain plastic homeostasis of the fetus in an unusual environment.

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[RNA-synthesizing activity in the liver of rats after a flight on the Kosmos 1667 biosatellite].

The effect of a short-term flight (7 days) on the RNA synthetic activity in isolated nuclei of the rat liver and its content of nucleic acids was investigated. Postflight the activity of RNA-polymerase, the key enzyme of RNA synthesis, increased. The endogenous synthesis of RNA in nuclei grew, probably, due to the change in the activity of RNA-polymerase. Conversely, the concentration of nucleic acids in the liver tended to decrease. The results obtained give evidence that the changes in the RNA synthetic apparatus of hepatocytes in short-term flights are similar in sign to those seen in long-term flights.

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[Effect of weightlessness on the DNA replicative function of rat hepatocytes].

The replicative function of DNA of liver cells of rats exposed to strong stress-effects, e.g. suspension for 2.5 hours a day for 6 days, decreased. The rat studies onboard biosatellites of the Cosmos series have demonstrated that a prolonged exposure to microgravity (up to 22 days) is not a stressogenic factor for the DNA synthetic system of liver cells. The transition from 1 g to microgravity cannot be viewed as a strong stressor either, because the rate of DNA synthesis in liver cells at an early period of adaptation to microgravity remains within the normal limits. However, this parameter decreases significantly during the recovery period following 18-22-day flights. Therefore changes in cellular processes related to the DNA replicating function in hepatocytes should be expected to occur in the postflight period rather than at an early period of adaptation to microgravity.

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[Matrix activity of chromatin DNA and the adenylate cyclase system in the tissues of rats after a flight aboard biosatellite "Cosmos-936"].

Chromatin DNA template activity and cAMP metabolism enzymes in the liver and lymph organs of rats flown for 19 days were studied. Postflight RNA synthesis on the chromatin DNA template was increased in the liver and decreased in lymph organs. Adenylate cyclase and phosphodiesterase activities decreased in the liver and increased in lymph organs. No correlation between cAMP enzyme activity and chromatin DNA template activity was found. The nature of the biochemical changes in animal tissues is discussed.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMedDate not supplied

[DNA radiation injuries in the liver of rats irradiated in flight on the Cosmos-690 biosatellite].

It was found that space flight factors enhanced radiation-induced DNA lesions in the liver of rats flown aboard the biosatellite Cosmos-690. Two weeks after irradiation of animals at a dose of 200 rad characteristic viscosity of native and denatured DNA decreased by 17 and 38%, respectively, as compared with the control. The radiation effect was also increased after an exposure to 800 rad.

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[State of rat liver and spleen DNA after space flight on the "Cosmos-605" satellite].

The effect of space flight on the content of nucleic acids and the structure of DNA in the rat liver and spleen was studied. The 22-day exposure did not influence the DNA content in tissues, whereas the RNA content decreased by 14% and 19% in the liver and spleen, respectively. The flight did not induce changes like one-stranded or paired breakages in the DNA structure. Studies of the liver showed a minor trend towards a fall of elastic viscosity of the DNA supermolecular structure (difference between the flight and control rats was statistically insignificant). The above changes in the state of nucleic acids in the liver and spleen were transient.

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[DNA depolymerase activity in rat spleen following flight on the "Kosmos-605= satellite].

The activity of enzymes involved in DNA disintegration (acid and alkaline DNA-ases) was measured in the spleen of rats flown onboard the Cosmos-605 biosatellite for 22 days. The activity of alkaline DNA-ase remained unaltered whereas that of acid DNA-ase increased more than twice. The activity of acid DNA-ase returned to the normal 26 days postflight. The study of characteristic viscosity (eta) of native and denatured DNA showed that enzyme activation was not followed by degradation changes in the DNA molecule.

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