[Immune system status under effect of low levels of ionizing radiation:studies within the 10 kilometer zone of accident at Chernobyl nuclear plant]. / Sostoianie immunnoi sistemy pri vozdeistvii malykh urovnei ioniziruiushchei radiatsii: issledovaniia v 10-kilometrovoi zone avarii na ChAES.

A study was made of the influence of high radiation contamination within the ten-kilometer zone of Chernobyl disaster on the structure and function of the immune system of (DBA x C57B1)F1 and DBA mice. The cumulative radiation doses with respect to gamma-radiation, were 0.024, 0.168 and 0.336 Gy. T-lymphocyte proliferation was shown the be activated with all radiation doses mentioned above but with doses of 0.024 and 0.168 Gy, helper T lymphocytes, and with 0.336 Gy, suppressor N-lymphocytes were primarily activated. So, in the former case, some effector functions of the immunity were activated, and in the latter, inhibited. It is concluded that certain hyperstimulation of the lymphoid cell formation (including the increase in T-suppressors), that is induced by long-term exposure to low-level radiation, triggers the mechanisms of autonomous regulation of the system that suppress the radiation-induced lymphocyte proliferation and inhibit the effector functions of the immunity.

[Radiation exposure of cultured tissue cells and animals (mice) within 10-kilometers zone of accident at Chernobyl nuclear plant. Effect on radiosensitivity to future radiation]. / Ekspozitsiia kletok v kulture tkani izhivotnykh (myshei) v 10-kilometrovoi zone avarii na ChAES. Vliianie na chuvstvitelnostk posleduiushchemu oblucheniiu.

The effect of chronic low-level radiation exposure on radiosensitivity to posterior acute irradiation at high doses has been studied. Cells and mice were exposed within the ten-kilometer zone of Chernobyl disaster during various spaces of time (1-12 days), then over one or more days were additionally irradiated by doses of 1-4 Gy. It was shown that no adaptive response was developed under chronic exposure of cells and mice within the zone of disaster. On the contrary increased sensitivity to posterior irradiation was revealed. The number of cytogenetic damages of cultured tissue cells and marrow cells (chromosome aberrations and micronuclei) increases, the spectrum of aberrations being shifted to chromosome type, cells with multiaberration appearing. The decay of chromatine increases indicating an interphase death; the number of leucocytes in peripheral blood decreases.