[Radiation risk in aircraft altitude flights]. / Radiatsionnyi risk pri vysotnykh aviatsionnykh poletakh.

The radiation risk in aircraft altitude flights was evaluated from calculated dose fields at the altitude of 10-30 km 0-90 degrees North modulated by the galactic cosmic radiation (GCR) in quiescent heliophysical periods. Results of dose measurements in flight are discussed in the light of present-day radiation limits. The authors suggest that pilots should be subsumed under the category of professionals who work with sources of ionizing radiation.

[The role of the vasoconstrictor effect in realizing the radioprotective properties of indralin in experiments on dogs]. / Rol' vazokonstriktornogo éffekta v realizatsii protivoluchevykh svoistv indralina v opytakh na sobakakh.

In the experiments on dogs, the role of a pharmacological circulatory hypoxia in the mechanism of radioprotective effect of indraline and mexamine was studied. Angiography revealed 20-40% vasoconstriction of major arteries of legs of animals, of pelvis and abdomen caused by mexamine (10 mg/kg) and the absence of a significant effect of indraline. Disruption of a regional blood circulation in the marrow and spleen (40-50% and 70-80%, respectively) was caused by indraline to the same extent as by mexamine. For indraline, a decrease in pO2 in the marrow was about 50%. With these hemodynamic disturbances, indraline showed 80 to 100% radioprotective effect, while mexamine was inefficient. Acute hypoxic hypoxia (5-7% O2) increased a post-radiation survival rate for dogs by 40%. The radioprotective effect of indraline was blocked by tropaphen and reduced in cases of breathing with pure oxygen. Splenectomy has no effect on radioprotective properties of indraline. Thus, a hypothesis of the mechanism of a radioprotective effect of alpha-adrenomimetics was proposed.

[Mechanism of the radiation-protective effect of indralin]. / K mekhanizmu protivoluchevogo deistviia indralina.

Pharmacological test demonstrated that radioprotective activity of indralin occurs by interaction with alpha-adrenoreceptor. Radioprotective effect of indralin decreased by alpha-adrenoblocker, aminazine and theophylline. Normobaric hyperoxia during irradiation reduced radioprotective effect of indralin in doses about ED50. In experiment with mice and rats it was shown that indralin induced acute hypoxia, impaired oxygen consumption and heat production by 30-46%, spleen bloodflow to 26.3% of control level, rectal temperature by 1.5-2 degrees C (mouse). After 30-min indralin raised resistance of mice to hypoxic hypoxia that is believed due to rapid development of biochemical adaptive process in hypoxic cells.

[The early reaction of the neuroendocrine system to irradiation at high doses]. / Ranniaia reaktsiia neiroéndokrinnoi sistemy pri obluchenii v vysokikh dozakh.

It has been found that in 2 hours after the total gamma irradiation of rats at doses of 20 and 100 Gy the ACTH and glucagon levels in plasma increased by 5-6 and 10-12 times correspondingly. No significant changes in levels of plasma insulin and glucose have been revealed.

[Radiation-modifying effect of hypoxia, and tissue basophils of skin in rats: possibility of individual prognosis]. / Radiomodifitsiruiushchee deistvie gipoksii i tkanevye bazofily kozhi u krys: vozmozhnosti individualnogo prognozirovaniia.

In experiments on rats the data about relationship between individual properties of skin tissue basophil population and animal's radioresistance under total gamma-irradiation (11 Gy) at severe hypoxia has been obtained. The method for estimation of state of tissue basophil population by means of reactivity index has been proposed. An opportunity for using of this index to predict some radiobiological patterns has been shown.

[Patterns of emotional and motivational interrelationships of irradiated male cats]. / Nekotorye zakonomernosti émotsional'no-motivatsionnykh vzaimootnoshenii u obluchennykh kotov.

After gamma irradiation within a wide range of doses (from 5 to 100 Gy) it was found that behavioural response of an emotional type (an evoked "pleasure" test) was more labile than the reaction based on a pronounced congenital hunter motivation (a "predator-victim" test). Exposure (50 Gy) of abdomen, when CNS was unaffected while a pronounced vegetative syndrome of the primary reaction developed within the first two hours, resulted in a more significant decrease in either behavioural pattern than it was observed after irradiation of the head.

[Changes in the therapeutic spectrum with respect to the pharmacological and radioprotective activity after O-alkylation of serotonin and 5(2-hydroxyethoxytryptamine)]. / Izmenenie terapevticheskoi shiroty deistviia po farmakologicheskomu i protivoluchevomu éffektu pri O-alkilirovanii serotonina i 5(2-oksiétoksitriptamina).

In experiments with mongrel mice, a study was made of the pharmacological activity of serotonin and its O-alkyl derivatives. It was estimated by the two indices, that is, the radioprotective properties and the influence on a local blood channel in the spleen, the modifying effect of the agents' toxicity being estimated as well. As an O-alkyl group of 5-alkoxytryptamines was elongated from one to three carbon atoms and the toxicity of the substances increased, their radioprotective effect decreased more readily than their effect on the local blood channel. The shortening of the range of the therapeutic action of the agents under study, with regard to the two pharmacological indices mentioned above, the alkyl group being lengthened, followed a logarithmic function which was more pronounced in relation to the radioprotective index (cos alpha 1/cos alpha 2 = 1.58).

[Comparison of changes in succinate dehydrogenase activity in blood lymphocytes and modification of radiosensitivity by exogenous hypoxia]. / Sopostavlenie izmeneniia aktivnosti suktsinatdegidrogenazy v limfotsitakh krovi i modifitsiruemoi radiochuvstvitel'nosti pod vliianiem ékzogennoi gipoksii.

Radioprotective efficiency of gas hypoxic mixtures (GHM) containing 5-12% of oxygen and the rate of the reaction of succinate dehydrogenase (VSDG) activity in peripheral blood lymphocytes upon breathing GHM were comparatively studied in rats and dogs. VSDG was 4393.5 (%O2)-2.58 and 130.76 (%O2)-1.42 in dogs and rats respectively. Taking into account that DMF in rats is a function of oxygen concentration in the mixture one can obtain a formula for determining a dose modifying factor (DMF) as a function of the rate of SDG activity reaction.

[Radiosensitivity during the irradiation of animals in an altered gaseous environment. A comparative study on mice and rats of the radiation-protective effect of oxygen-deficient gas mixtures]. / Radiochuvstvitel'nost' pri obluchenii zhivotnykh v izmenennoi gazovoi srede. Sravnitel'noe issledovanie na myshakh i krysakh protivoluchevogo éffekta kisloroddefitsitnykh gazovykh smesei.

The radioprotective effect of gas hypoxic mixtures containing 5, 7, 8, 10 and 15% of oxygen on mice and rats was comparatively studied. The dependence of DMF upon oxygen concentration in the mixture was approximated by a hyperbolic function similar to the dependence of the radiomodifying effect of circulatory hypoxia caused by radioprotective agents of the indolylalkylamine series.

[Radiosensitivity of animals irradiated in a modified gaseous medium. Modification of cerebral syndrome in mice by hypoxic hypoxia and hyperoxia during irradiation]. / Radiochuvstvitel'nost' organizma pri obluchenii zhivotnykh v izmenennoi gazovoi srede. Modifikatsiia tserebral'nogo sindroma u myshei gipoksicheskoi gipoksiei i giperoksiei vo vremia oblucheniia.

The cerebral syndrome of mice was shown to be modified by the use of a changed gas medium during irradiation of the head. This was manifested by the decrease in the severity of the syndrome in the hypoxic medium (HGM-8) and aggravation in the hyperoxic medium. When the body was exposed the modifications of the radiation damage were opposite.

[Characteristics of the role of the hydroxyl group in serotonin in the pharmacological and antiradiation effect of serotonin]. / K kharakteristike roli gidroksil'noi gruppy serotonina v farmakologicheskom i protivoluchevom éffekte serotonina.

It was shown that omega-hydroxylation of O-alkyl serotonin derivatives can slightly improve the radioprotective and pharmacological properties of these substances but fails to remove completely the unfavourable action of O-alkylation of serotonin. There is a close correlation between the radioprotective effect of 5-oxyalkoxytryptamines and their action on blood supply of mouse spleen. The introduction of the alkoxy-group or the tertiary amino-group into omega-position removes the radioprotective effect of 5-alkoxytryptamines.