Radiobiologiia最新文献

Repeated exposure of guinea pigs to microwave radiation (1 mW/cm2) caused in some animals inhibition of anaphylactic response accompanied by increasing the content of histamine, epinephrine and norepinephrine in the blood. This increase was more pronounced in irradiated guinea pigs died from anaphylactic shock than in nonirradiated animals. The long-term stay in the perturbed and weak geometric field reduced the effect induced by microwave radiation.

The structural status of plasma membranes of adipose tissue and liver of rats was investigated at remote times (from 15 to 380 days) after single 1-Gy gamma irradiation. The structural status was estimated by pyrene excimerisation parameters and also by both induction resonance energy transfer method and membrane tryptophan fluorescence spectral characteristics. On days 50-100 following irradiation the microviscosity of a lipid phase of membranes increased and the mode of lipid/protein interactions changed, whereas at later times the indices under study did not vary from the controls. Comparison of the data obtained with the former results on lipid content changes indicates that the physicochemical status of plasma membranes in rat adipose tissue and liver is modified at remote times following 1-Gy gamma irradiation.

There is three major sites of radioactive environmental contamination in the former USSR: the Chelyabinsk region in the Urals, Chernobyl NPP in Ukraine and Novaya Zemlya in the Arctic Ocean. The first mentioned is the most important with regard to local (potential) contamination, the last one dominates the global contamination. A number of sites and sources are less well known with regard to environmental contamination. This is thus the case for the plutonium production factories at Tomsk and Dodonovo. More information on nuclear reactors in lost or dumped submarines is also needed. From a global point of view reliable assessment of the radioactive run-off from land and deposits of nuclear waste in the Arctic Ocean are in particular pertinent.

S,beta-Amidinoethyl thiophosphate, a radioprotective agent that was synthesized and studied, was shown to have certain advantages over cystamine: it was effective when used in a lesser amount; it was less toxic, had higher therapeutic effect, and, in contrast to castamine, it did not inhibit physical efficiency of animals. S,beta-Amidinoethyl thiophosphate and gammaphos were very similar in properties.

An extract from regenerating calf spleen increases the survival rate of mice when injected after irradiation. The studies of the blood and immune systems characteristics at the subcellular, cellular and tissue levels have been shown that the preparation containing a complex of hemoregulating compounds modifies the processes responsible for radiation damage and repair.

X irradiation of Chinese fibroblasts with doses of 0.05-0.15 Gy was shown to cause intracellular pH (pHi) changes: its diminishing during the first 40-60 min by 0.16-0.18 pH units, then the return to the control level 120 min after irradiation and, finally, the increase by 0.18-0.20 pH units. Simultaneously, the synthesizing activity of the cells changed in the same way. The ATP level changed in the opposite way: increased when pH fell and decreased when pH grew. It was shown that pHi changes were connected with the changes in Na+/H(+)-exchange system, and they seemed to be primary in the chain of the alterations observed.

This paper presents the results of radioecological studies undertaken within the area exposed to ionizing radiation after Chernobyl disaster. Conclusions are made concerning the major regularities in radionuclide migration within various natural media and action of ionizing radiation on natural and artificial ecosystems. The efficiency of basic protective ecological measures in eliminating the accident consequences has been determined. The contribution of radioecological studies to the elimination of Chernobyl disaster sequences assessed.

From the analysis of the literature it is inferred that there is one more type of nonspecific protection which is based on the polyploidy process and functions at the cell population and tissue levels. With high radiation loads, this process maintains the functioning rate of the given tissue and the survival rate of the given cell type. A hypothesis is proposed that cell fusion and formation of somatic hybrids, that provide clone survival, are particularly effective in tumor tissues. This mechanism is activated at high radiation doses: fusion of injured cells and formation of polykaryons and then hybrids can give rise to cells capable of reproduction. The cellularity is restored.

The influence of water-soluble polysaccharides of Viscum album L. on the survival of mice subjected to whole-body gamma-irradiation has been investigated. Polysaccharides were shown to exert a radioprotective effect which was a function of both the radiation dose and the drug dose and time of its injection. The maximum radioprotective efficacy of polysaccharides was observed after their injection 15 min before irradiation. A single intraperitoneal administration of polysaccharides (25 mg/kg) before irradiation with LD50/30 and LD100/10-12 increased the 60-day survival rate up to 95% and 27% respectively. The postirradiation injection of polysaccharides prevented death of 80% of mice given LD50 and increased the average life expectancy of animals irradiated with absolutely lethal doses.