Radiobiologiia最新文献

Radiosensitivity of male and female lymphocytes exposed to gamma radiation (60Co) in phase G0 of the mitotic cycle has been comparatively studied. The radiosensitivity was shown to be identical, within the limits of error, although with the recombination repair (the nonhomologous nature of X and Y chromosomes being taken into account) the number of chromosome aberrations in male cells must be 1.4 times larger than in female cells. This indicates an absence or (within the limits of error) an insignificant role of the recombination repair of double-strand DNA breaks.

There was a 30% increase in spermatozoids with microheads and a 3-fold increase in "young" spermatozoids at later times after irradiation of BALB/c mice a dose of 1.0 Gy. With radiation doses of 0.1-1.0 Gy, BALB/c and CBA mice (which differ in viability of spermatogenous cells, the number of Sertoli cells and total embryonal death rate) exhibited a significant increase in the preimplantation death at the stage of spermatogonia and stem cells. The results obtained indicate reduction of the fertilizing capacity of sperm which is probably realized as dominant lethal mutations.

In studying the radioprotective action of natural and synthesised antioxydants a decreased yield of chromosome aberrations with respect to those in untreated cells was noted in normal cells irradiated in phase G1 whereas no radioprotective effect was found in cells irradiated in G0. The addition of antioxydants into the cell cultures from patients with Turner's syndrome did not change their radiosensitivity. No adaptive response was induced in lymphocytes from patients with Down's syndrome cultivated with vitamin E.

The method of 31P NMR in vivo was used to study phosphorylated metabolite dynamics in rat brain after a single gamma-radiation dose of 6.5 Gy. A reversible decrease in a relative concentration of inorganic phosphate and an increase in intracellular pH were noted 24 h after irradiation. The diphosphodiether level decreased 6 days after irradiation.

The effect of an anthocyan preparation isolated from flower petals of Pelargonium roseum and Rosa canina was studied in the Chinese hamster fibroblasts and Vicia faba seedlings in respect of cytogenetic damage and mouse survival. The pronounced radioprotective effect and the absence of the toxic effect were observed.

Whole-body X irradiation with doses of 0.155 and 0.310 C/kg was shown to modify in different ways the activating effects of noradrenaline and serotonin, as well as a biphase effect of dopamine (5.10(-8)--1.5.10(-3) M) on Na,K-pump of neuronal membranes. The resulting effect was a function of a combination of radiation doses and neurotransmitter concentrations and thus showed different modes of interaction between neurotransmitter and ion-transport systems of brain cells in radiation sickness. The authors discuss possible molecular mechanisms of radiation modification of the functional interaction between the neurotransmitter and the active ion-transport systems in nerve cells.

Ionole antioxidant (5 x 10(-6) M) was administered to haemolytic complement system and its components (i.e. suspension of erythrocytes sensitized by rabbit antibodies and blood serum). The general effect of the complement system photoinactivation (4.53 x 10(2) J/m2) was attributed to the direct effect of UV-light on the blood serum proteins (approximately 68%) and indirect effect via radical products (approximately 32%).

A bacterial model is proposed for the prognosing, at the cellular level, of the effectiveness and safety of low-intensity laser therapy. In experiments with E. coli WP2, a study was made of the effect of continuous optical radiation as well as of pulse radiation at medical installations "Uzor" (890 nm, 1.2 x 10(-1) W/m2, 3400 Hz) and "Omega" (950 nm, 1.2 x 10(3) W/m2, 2-5000 Hz). A technique has been developed to determine a minimum dose of low-intensity radiation that provides normalization of the cell division rate at a pathological site excluding the risk of the uncontrolled proliferation of the surrounding tissues.

The effect of long-term (9 months) exposure to electric field (17 kHz, 100 kV/m) on mouse testis has been investigated. The increase in destructive processes was noted in both spermatogenous epithelium cells and in steroid-producing cells; the histohematic barrier status changed. The results obtained indicate premature reproductive ageing of animals under the effect of electric field.

Experimental data on the effects of radiation and hyperthermia on Chinchilla rabbits are presented. Multiple exposure to heat (40 degrees C, 20 min) between two radiation fractions was shown to influence favourably such haematological indexes as leukocyte and erythrocyte number and life-span of irradiated animals. Extra (to irradiation + heat) hyperthermia applied immediately before irradiation increased the radiation effect.