Radiobiologiia最新文献

Early transient incapacity and cerebral radiation syndrome were shown to result from the de-energizing of the brain due to NAD and ATP neuron pools depletion since DNA breaks stimulate the repair enzyme, ADP-ribosyltransferase, that consumes NAD as a substrate. The phenomenology of syndromes, peculiarities of the CNS repair and neutron RBE might be attributed to this mechanism. DNA is thus a common target for stochastic, deterministic and physiological effects of radiation.

The paper presents the review of the author's own data and the results obtained by other investigators concerning remote effects of the NFP-induced affection. The information on the metabolism and clinical picture of acute NFP-induced damages was presented in Report 1 (Radiobiologiia, 1982, No 1).

Alteration dynamics of 5'-nucleotidase (EC 3.1.3.5) in rat plasma was studied after whole-body gamma-irradiation. External gamma-irradiation with doses ranging from 0.5 to 11 Gy induced a transient rise of 5'-nucleotidase activity. An increase in the enzyme activity was found to be a function of dosage and post-exposure time. The moment of enzyme activity rise vs dose was represented as an exponential curve. The rise in plasma 5'-nucleotidase activity was assumed to be the result of lesions in flexible tissue (type F).

In experiments with mice exposed to gamma quanta (6.0 Gy) it was shown that a single injection of disodium salt of 2,4-di(alpha-methoxyethyl)deuteroporphyrin IX (50 and 12 mg/kg) both 15 min before and 15 min after irradiation promoted postirradiation regeneration of all bone marrow haemopoiesis compartments. The agent produced a more pronounced stimulatory effect when administered after irradiation.

Three-day rat pups were X-irradiated (5 Gy) and killed on days 3-4, 6-7, and 10-11. Using the microscopic, histological and morphometric methods it was found that the microcirculation channel was damaged to a greater extent than the hemocirculation one. This was followed up during the radiation sickness. The pathological changes were more pronounced in all structures of the derma papillary layer than in those of the reticular layer. Oedema and reduced cellularity were noted in the connective frame.

A study was made of the influence of He-Ne laser radiation (lambda = 632.8 nm) on spontaneous chemiluminescence (CL) of human neutrophils as well as its effect on CL stimulated by calcium ionophore (A23187) and protein kinase activator (phorbol-12-myristate-13-acetate, PMA). In vitro irradiation of the blood and a neutrophil suspension activated spontaneous CL and modulated that stimulated by A23187 (1 microM) and PMA (10 nM) within the dose range from 0.01 to 6 J/cm3. The modulation effect of irradiation is a function of radiation dose and the initial value of the integral index of stimulated CL.

The intensity of fluorescence of amino acid and globular protein solutions, exposed to a pulsed electron beam in the presence and absence of the concurrent pulsed electromagnetic field was found to be a function of radiation dose. The observed decline in the fluorescence intensity was slightly dependent on the solution concentration and dependent on the time and dose-rate of irradiation. The effect of the concurrent pulsed radiation of the electromagnetic field was sometimes observed.

Irradiation of thymus with doses of 0.5 to 10 Gy and gonads with 10 Gy does not influence the growth of the tumor transplanted 10 days after irradiation and accelerates the growth of the tumor transplanted 11-12 months after exposure. Irradiation of hypophysis and hypothalamus with doses of 1 and 10 Gy accelerates the growth of the tumor transplanted 10 days and 11-12 months after exposure. In the latter case the effect was more pronounced. When thymus, hypothalamus and hypophysis were exposed simultaneously the effect was analogous to that observed after isolated exposure of hypothalamus/hypophysis but somewhat more pronounced. Irradiation of hypothalamus/hypophysis caused earlier and severer changes in the anti-tumor resistance than the exposure of thymus and gonads did.

The hypothalamo-hypophysis-gonad system was studied in male rats 1, 3 and 6 months after external irradiation with doses of 2 and 3 Gy. Irradiation with a dose of 3 Gy was shown to cause a decrease in the level of LH and testosterone in blood plasma, impairment of steroidogenesis in the testes and diminution of their mass. All this was most pronounced 6 months after X irradiation. The morphofunctional status of prostate, inhibited by X radiation, was restored by that time.

Two hours before irradiation (7.5 Gy) mice were injected with quinoid radiotoxins in concentrations close to those formed in mouse blood after gamma-irradiation with a dose of 10 cGy. This increased the survival rate (from 10-20% to 80%), prevented the radiation-induced weight loss, and increased catalase activity in the liver and blood of exposed animals.