[Indometofen causes biochemical changes in the blood cells characteristic for a radioresistant state of the body]. / Indometofen vyzyvaet v kletkakh krovi biokhimicheskie izmeneniia, kharakternye dlia radiorezistentnogo sostoianiia organizma.

The DNA and RNA contents, RNA/DNA ratio, and spontaneous and latex-induced oxidant activity indices of the whole blood were studied in the nitroblue tetrazolium test of mono- and polymorphonuclear blood leucocytes of intact dogs after injection of lipopolysaccharide pyrogenal. Significant changes in the above parameters were revealed for radioresistant (survived) and radiosensitive (lost) animals exposed to a subsequent prolonged gamma irradiation with a lethal dose of 7.64 Gy (LD75/45). Peroral introduction of 30 mg/kg indometofen (an indole analog of tamoxifen), which is a potential radioprotector, to dogs increased the survival rates of the irradiated dogs up to 93% and aided in the adaptive biochemical changes in the nuclear cell compartment of blood to induce a radioresistant status of the organism.

[The effect of ionizing radiation at superhigh doses on the processes of dopamine release and reuptake by nerve endings in different sections of the brain]. / Vliianie ioniziruiushchego izlucheniia v sverkhvysokikh dozakh na protsessy vysvobozhdeniia i obratnogo zakhvata dofamina nervnymi terminaliami razlichnykh otdelov golovnogo mozga.

Rats exposed to fast 24 MeV electrons (100 Gy) at the state of early transient incapacity (ETI) exhibited active release and reuptake of dopamine in nerve terminals of the striatum. No changes in the indices under study were found in rats exposed to 25 Gy radiation that did not cause the ETI development. The in vitro irradiation of the isolated synaptosomes (100 Gy) inhibited dopamine reuptake and increased the number of sites of 3H-spiperone binding to D2-receptors in a membrane fraction isolated from the striatum.

[Reasons for the quantitative differences in the formation of chromatin breakdown products following exposure to neutrons and gamma radiation]. / O prichinakh kolichestvennykh razlichii v obrazovanii produktov raspada khromatina posle vozdeistviia neitronov i gamma-izlucheniia.

Relative content of salt-soluble chromatin fragments in rat thymus increased after the effect of neutrons, as compared to gamma-radiation, while cell depletion of the organ was similar with both types of radiation. This was not associated with the rate and extent of chromatin degradation in thymocytes and was an indication of death of a larger number of thymocytes after the effect of neutrons.

[Early changes in the lymphocyte surface membrane of rats after whole-body irradiation with neutrons and gamma rays]. / Rannie izmeneniia membran kletochnoi poverkhnosti limfotsitov u krys posle obshchego vozdeistviia neitronov i gamma-izlucheniia.

Biochemical changes in lymphocyte plasma membranes were studied 3 and 18 h after whole-body exposure of rats to neutrons and gamma-rays at doses from 2 to 6 Gy. It was shown that fast neutrons, with an average energy of 1.5-2.0 MeV, increased the rate of lipid peroxidation more markedly than gamma-rays did. In addition, there was an increase in the number of free aminogroups on the thymocyte surface. Dose- and time-dependent parameters of changes in the aminogroup content on the cellular surface were quantitatively different after the effect of radiation with different LET.

[Characteristics of chromatin breakdown in the rat thymus after exposure to fast neutrons and gamma rays]. / Osobennosti raspada khromatina timusa krys posle vozdeistviia bystrykh neitronov i gamma-luchei.

A comparative study was made of the radiobiological aftereffects of the action of fast neutrons and gamma-rays on lymphoid tissues of rat thymus with a reference to a biochemical criterion of the interphase death of lymphocytes, i.e. the formation of polydeoxynucleotides (PDN). It was shown that the increase in the chromatin degradation was a function of dose of neutron- and gamma-radiation (up to 4 Gy). The dynamics of the PDN formation was similar with both types of radiation, but 4-6 h after neutron irradiation chromatin degradation was higher more pronounced. The RBE of neutrons varied from 3 to 2 with a radiation dose varying from 0.25 to 4 Gy.