[Rate of free radical peroxidation of lipids, activity of adenylate cyclase and permeability of plasma membrane for Ca2+ ions in cells of peripheral blood of sheep exposed to low-level radiation].

Chronic exposure of sheep at doses 0.1 and 0.5 Gy resulted in reduced contents of malondialdehyde, of diene and of triene conjugates and alpha-tocopherol with simultaneous increase in the retinol level in blood plasma. In lymphocytes of peripheral blood, the activity of adenylate cyclase was decreased, and in thrombocytes the phase pattern of changes was marked. The enzyme activity in blood cells stimulated by forskolin and prostaglandid E1 was more pronounced. The estimation of the plasma membrane permeability for Ca2+ ions in peripheral blood neutrophils has revealed nonlinear pattern of variations. Erythrocytes the showed increase in passive permeability of plasma membrane for Ca2+ ions.

[Evaluation of cell membrane permeability for Ca2+ and adenylate cyclase in sheep peripheral blood cells, exposed to low doses of radiation]. / Otsenka pronitsaemosti plazmaticheskoi membrany dlia Ca2+ i aktivnosti adenilattsiklazy v kletkakh perifericheskoi krovi ovets, obluchennykh v malykh dozakh.

Chronic irradiation of sheep with doses of 2.6 and 12.9 mC.kg was characterized by the modification of the adenylatecyclase activity and Ca2+ permeability of plasma membrane in cells of the peripheric blood, with no changes in the clinical and hematological indicators. The observed effects are assumed to result from structural and dynamic variations in the lipids of membranes.

[Increased plasma membrane permeability for Ca2+ in radiation-induced thymocyte apoptosis]. / Uvelichenie pronitsaemosti plazmaticheskoi membrany dlia Ca2+ pri radiatsionno-indutsirovannom apoptoze timotsitov.

Parameters of the Ca2+ permeability (the 45Ca influx rate in the presence of orthovanadate blocking the Ca(2+)-ATPhase, and the initial rate of the 45Ca uptake) and the DNA fragmentation were determined in rat thymocytes after gamma-irradiation-induced (with a dose of 5 Gy) apoptosis. Within the first 30-90 min after irradiation, the 45Ca influx rate that is characteristic of the membrane passive permeability remained unchanged. The initial rate of the 45Ca uptake that is characteristic of the Ca2+ exchange almost doubled. In 90-180 min, the rate of the 45Ca influx in the irradiated cells increased 1.5 to 2.0 times. An increase in the DNA fragmentation was observed in 90-120 min after irradiation of thymocytes; in 3 h, it developed up to 50%. Thus, modification of the membrane Ca2+ permeability in the irradiated thymocytes precedes a stage of initiation of the DNA degradation. A degree of disturbance of the membrane passive permeability increases as the thymocyte apoptosis progresses. The obtained data suggest that disturbance of the passive Ca2+ permeability and the intracellular Ca2+ homeostasis are responsible for the apoptosis of lethally irradiated thymocytes.

[The ATP content of the neutrophils and whole blood in the inhabitants of regions in the Altai Territory subjected to nuclear testing exposure]. / Soderzhanie ATF v neitrofilakh i tsel'noi krovi u zhitelei raionov Altaiskogo kraia, podvergshikhsia vozdeistviiu iadernykh ispytanii.

The bioluminescent method was used in the studies of the influence of ionizing irradiation and/or xenobiotics on the content of ATP in RBC and neutrophils of rats, and in whole blood and neutrophils of 80 examined women of Altai Region exposed to ionizing radiation during a series of nuclear tests in Semipalatinsk in 1949-1965. Deviations from the normal ATP content were measured with due to account of the natural variability of a given metabolite. For rats, deviations from the content of ATP in erythrocytes were short-term, those in neutrophils were long-term. For people, a statistically significant increase in the content of ATP in neutrophils as compared to the control was observed. A non-linear correlation between the content of ATP in neutrophils and the calculated dose of radiation was observed. An increase in the ATP content in whole blood, with regard to the control, was not statistically significant for all groups of examined persons.

[Modification of Ca2+ metabolism in the blood cells of cattle with radiation-induced thyroid disorder after the Chernobyl nuclear power plant accident]. / Modifikatsiia obmena Ca2+ v kletkakh krovi korov s radiatsionnym povrezhdeniem shchitovidnoi zhelezy posle avarii na Chernobylskoi AES.

Increasing of Ca2+ concentration in cytoplasm and of the rate of 45Ca iflux into cows erythrocytes in 19-24 month after Chernobyl accident was revealed. Correlation between Ca2+ concentration in cytoplasm of erythrocytes and thyroxin content in plasma of cows with radioiodine damage of thyroid gland was found. Reduction of the rate of 45Ga influx into erythrocytes in cows with radiation doses of 20-60 By on thyroid gland was shown in later time after accident (3-5 years). Changes in Ca2+ permeability through membranes of erythrocytes and neutrophils after injection of 131I into calves in doses of 300 Gy and more on thyroid gland was found.