[Effect of motor activity on the development of arrhythmia in experimental emotional stress].

Studies on monkeys and rabbits have shown that the experimental emotional stress can produce various disorders of cardiac rhythm: sinus tachycardia, atrial fibrillation, ventricular extrasystoles and paroxysmal ventricular tachysystoles. In these conditions the adrenaline content in the blood and myocardium is increased 3-4 times, the noradrenaline level is raised in the blood and decreased in the myocardium. Moderate motor activity leads to a relative decrease of adrenaline in the myocardium and arrest of cardiac arrhythmias.

[Biosynthesis of rat hemoglobin fractions under normal and increased erythropoiesis].

Studies of erythroid elements of hematopoietic organs and peripheric blood and bone marrow cell populations fractionated by precipitation in an albumin density gradient and synchronized by actinomycin D revealed that the rate of synthesis of individual haemoglobin fractions in the course of erythropoiesis is changed. The proliferating cells are characterized by a predominant accumulation of haemoglobin in fractions with beta c-and in the maturing cells--with beta b-chains. The radioactivity in the whole population of hematopoietic organs under phenylhydrazine anemia is mainly increased in the beta c-chains, whereas under the effects of erythropoietic factors (erythropoietin, animal sera)--that of beta b-chains is increased.

[On the nature of rat hemoglobin heterogeneity].

Rat hemoglobin was fractionated by different methods. It is shown that the heterogenic system of hemoglobin includes six main fractions, the appearance of which is determined by 2 alpha- and 3 beta-similar chains. A subunit composition is established for hemoglobins certain fractions and their tetrameric structure is as follows: formula: (see text).

[Morphogenetic shift of hemoglobin types in the ontogeny of rats].

The embryonic haemoglobin represented by 4 fractions was shown to form in the nucleate erythroid cells of the yolk sac. The dynamics of their quantitative changes was determined in 10 to 14 days old embryos. Anuclear red cells of the subsequent haemopoietic centers synthesize the heterogenous haemoglobin system (fractions 1--6).