[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.

[Effect of mexamine on arterial tonus in dogs]. / Vliianie meksamina na tonus arterii u sobak.

The effect of mexamin (5 and 10 mg/kg) on the vascular tone of thoracic and abdominal cavity vessels and pelvic limbs was investigated by angiography in experiments on 19 mongrel dogs under nembutal anesthesia (30 mg/kg). 5-7 minutes after intramuscular administration of the drug there was a constriction of the aorta, of the hepatic, splenic, cranial mesenteric, internal and external iliac, branched femoral and tibial arteries by about 15-40% as compared to the initial diameter. Mexamin exerted no substantial vasoconstrictive action on the segmental (intercostal, lumbar, phrenoabdominal) and renal arteries.

[Problems in the pathogenesis of respiratory disorders occurring under +Gz loads in combination with breathing of pure oxygen]. / Nekotorye voprosy patogeneza respiratornykh rasstroistv, voznikaiushchikh pri peregruzkakh +Gz v sochetanii s dykhaniem chistym kislorodom.

The effect of accelerations of different value and duration combined with air or pure oxygen breathing on the pulmonary function was investigated in centrifugation experiments on six healthy male test subjects, aged 20--23. The dynamics of the emergence and back development of the respiratory syndrome induced by the combined effect of acceleration and pure oxygen breathing, its symptoms, spyrographic and roentgenologic components were studied. It was demonstrated that both the value and duration of acceleration played a certain role in the pathogenesis of functional disorders of the respiratory system and atelectasis; however, the time factor exerted the major effect on their development.