Radiobiologiia最新文献

Strontium 90 was given to rats with the diet over a period of 3 months. Administration of a modified calcium alginate reduced 90Sr deposition in the skeleton by 70-90%. No changes in the digestive organs were observed throughout the above period.

A study was made of the formation and repair of apurine-apyrimidine (AP) sites in DNA of gamma-irradiated 3- and 7-day embryos of Bombyx mori differing drastically in radiosensitivity. The number of AP-sites in DNA immediately after irradiation was much larger in DNA of 3-day embryos than in DNA of 7-day embryos. The kinetics of the postirradiation recovery of AP sites in DNA of 3- and 7-day Bombyx mori embryos was heterogeneous and varied significantly.

Human lymphocytes, in the in vitro culture, exposed to X-rays (0.05 Gy) or treated with lymphoblastoid interferon (50 IE/ml) in phase G1 were less susceptible to induction of chromosome aberrations, of a chromosome type, by subsequent gamma-radiation (2 Gy) than those exposed to 2 Gy radiation only. The anticlastogenic effect of the pretreatment with interferon was considerably higher than that of preirradiation with X-rays which might be the result of the pleiotropic action of interferon in a cell.

Thermal burn of irradiated rats increases the level and the length of the postirradiation enteroendotoxemia and aggravates the postirradiation impairment of the hematoenterocitic barrier. The pharmacological correction of the small intestine motility and introduction of ciproheptadine, an agent that blocks serotonin receptors, ameliorates the above phenomenon in radiation and thermal injuries.

A study was made of the effect of gamma radiation on proliferation of thymus stroma epithelial cells (EC) of newborn mice (CBA x C57Bl/6)P1 where EC content varied from 55% to 85%. EC proliferation was assessed 24 and 48 h after gamma irradiation by studying the mitotic activity of thymus EC and rate of MTT recovery (which permitted us to determine the nature of proliferating cells by their morphology). The quantitative characteristics of the two methods were identical. The effect of gamma radiation was assessed at various cultivation times. Irradiation at the time of inoculation reduced the proliferation of cells to logarithmic phase of growth. Irradiation with doses of 10 and 20 Gy after two-day cultivation inhibited proliferation of thymus EC and with 15 Gy increased the proliferative activity of thymus epithelium.

In experiments with Chinese hamster cells and Ehrlich ascites tumor cells it has been shown that a decrease in intracellular pH from 7.0 to 6.0, produced by 0.1 M phosphate buffer, ameliorates the radiation injury to cells (DMF = 1.35) with respect to their clonogenic capacity and induction of chromosome aberrations. The rate of repair of DNA single-strand breaks, within the pH range under study, is invariable.

Activity and isoenzyme composition of certain enzymes of glycolysis of rat small intestine enterocytes was studied in the course of exposure to X radiation. Hexokinase activity was shown to increase significantly throughout the entire period of observation. Activity of pyruvate kinase and lactate dehydrogenase was inhibited at early (days 1-3) and increased at later (days 5-10) times of observation.

In studying the pattern of chromosome aberration distribution among hydrobiont cells in experimental and natural populations, it has been found that the Poisson distribution of chromosomes among cells occurs under the effect of ionizing radiation and under the combined effect of radiation and a chemical mutagen with a higher efficiency of the former. With the comparable efficiencies of both factors and with the effect of a chemical mutagen alone distribution of chromosome aberrations among cells resembles the geometrical one to a greater extent.

The influence of incorporated cesium 137 (the absorbed doses of 0.26-0.08 Gy) on the erythrocyte membrane structure has been investigated. It has been shown that chronic internal exposure to gamma radiation causes structural reorganization of erythrocyte membranes at remote postirradiation times (in 3 and 6 months) that influences the annular membrane lipid.

It was for the first time that of the fifth year of monitoring of Plantago lanceolata L., reproduced within the thirty-kilometer zone of Chernobyl NPP disaster, the authors discovered high incidence of seedlings with various morphological abnormalities. It is suggested that the damages observed are related to the cumulative effect of radiation.