Radiobiologiia最新文献

The radioprotective effect of cysteamine has been studied in larva nerve ganglia of the radiosensitive mutant rad(20)201G1, mutagen-sensitive mutant mus(2)201G1 and the control strain of drosophila. Cysteamine was shown to produce a radioprotective effect in somatic cells of mus(2)201G1 and the control strain of drosophila which was manifested by the decreased incidence of cells with chromosome aberrations and diminished yield of deletions and exchanges. No significant radioprotective effect of cysteamine was observed in somatic cells of rad(2)201G1 mutant.

Plasma membrane thymocytes were irradiated with doses of 10-10(4) Gy in the presence of 125 and 1125 mu mol of Ca2+ per 1 mg of membrane proteins. Fluorescence of 1-anilinonaphthalene-8-sulphonate and the degree of pyren eximerization were determined. The data obtained indicate that calcium can exert a stabilizing effect on the plasma membrane structure affected by radiation.

In experiments with 933 (CBA x C57Bl)F1 mice it has been found that with any variant of alternation and sequence of single ionizing and SHF irradiation with lethal doses, the radiation affection caused by gamma quanta is aggravated. Preirradiation with gamma or SHF radiation ameliorates the severity of the affection caused by the subsequent SHF radiation. Parenteral injection of colloidal sulfur 60 min before SHF radiation causes a 2-5-fold increase in the survival rate of exposed and protected mice as compared to unprotected animals.

Was determined quantity places and constant binding of calcium with plasma membranes thymocytes at rats, that was irradiation at doses 7 Gr. Was establish that to 22 days after irradiation the binding Ca2+ with membranes was return to control.

In seasonal experiments (spring and autumn) with Wistar female rats, a study was made of the level of lipopigments (LP) and alpha-tocopherol (TPh) fluorescence in the liver and brain. Seasonal peculiarities of the parameters under study and their dependence on Vitamin E ingestion have been revealed. After irradiation of animals, an intimate morphofunctional relationship between LP and TP and its sensitivity to alimentary factors have been found. One hour following irradiation, part of LP is disintegrated thus releasing the TPh reserve. This may be the part of the complex of adaptation changes on the postirradiation metabolic effects.

A study was made of lipid composition of plasma membranes of adipose tissue and liver of rats at remote times (from 15 to 380 days) after single 1-Gy gamma irradiation. The changes in membrane lipids were most pronounced during the first 50 days after irradiation: the cholesterol level increased (the phospholipid content in the adipose tissue decreased) and the relative content of linoleic (18:2), arachidonic (20:4) and other unsaturated fatty acids decreased. At later times following irradiation, the molar cholesterol/phospholipid ratio in membranes of experimental animals did not vary from the control and relative content of unsaturated fatty acids somewhat increased as compared to that of intact animals of the same age.

From experiments in mice, it is shown that with a radiation dose of 8 Gy (LD96) the radioprotective effect was exerted by gamma-aminobutyric acid (GABA), substances that increase its concentration in tissues (progabide and valproate), and synthetic agonists of both receptor types, particularly baclofen, a GABA-receptor agonist. The radioprotective effect is also exerted by gamma-hydroxybutyrate, not piracetam.

A study was made of the formation of cataract in rats at remote times after whole-body and partial X irradiation. The whole-body radiation loses were 5 and 10 Gy (two fractions of 5 Gy at a 30-day interval). Partial exposure of the head and neck, as well as irradiation of chest were performed with doses of 5, 10 (two fractions at a 30-day interval) and 15 Gy (three 5 Gy fractions at a 30-day interval). It has been shown that cataract develops not only due to the direct effect of radiation on the eye, but also to indirect effect on the experimental animal body (with irradiation of the abdomen and diabetes development).

A study was made of the effect of gamma-ray dose fractionation registered by chromosome aberration induction in somatic cells of the mutant rad(2)201G1, the mutant mus(2)201G1, and the wild type strain of drosophila. The dose fractionation upon irradiation of the mutant mus(2)201G1 and control strain larvae was shown to decrease the frequency of cytogenetic damages to cells. In contrast, when the radiosensitive mutant rad(2)201G1 was exposed, the effect of dose fractionation was insignificant.

The survival rate of mice gamma-irradiated at different times after administration of Cd2+ (0.75 mg/kg) was shown to be tightly connected with the amount of metallothioneins induced by this heavy metal in the bone marrow (r = 0.96). The connection between the amount of metallothioneins in the liver and the survival rate was less pronounced.