Measurement of the intensity of erythropoiesis based on the RNA content of erythrocytes

The relationship between RNA content in erythrocytes and the erythropoiesis rate was studied at varying exposures as a result of which a simple method for erythropoietic activity testing was proposed. It consists in the measurement of ribonucleic acid content in erythrocytes of mice with a decreased erythropoiesis after administration of the test sample. Erythropoietic activity is determined from the magnitude found. The method suggested is marked by simplicity and higher sensitivity and thus may be applied in clinical medicine and research.     

Indicators of pituitary-thyroid system and lipid metabolism in female representatives of the Buryat ethnos and Europeoids

Specific features of indicators of the thyroid status and blood serum lipoprotein level were revealed in girls and women of the Buryat ethnos and Europeoid race. Buryat versus Europeoid females develop adaptive responses of the pituitary-thyroid part of the neuroendocrine regulatory system (increased free T3 levels in girls and decreased TTH levels in women). Changes in lipid metabolism indicators consist in lower levels of atherogenic cholesterol fractions in Buryat girls and higher levels of cholesterol-containing blood components in Europeoid adolescents. At the older ages, an inverse tendency is observed, characterized by a higher activity of lipid metabolism in females of the indigenous nationality.     

Features of compensatory-adaptive reactions of an organism in female representatives of the Evenk ethnos

Adolescent girls and women of reproductive age, female representatives of the Evenk ethnos and Europeoids that co-inhabit the north of the Irkutsk oblast, were examined. Changes in metabolic reactions in the small indigenous ethnic group were found to have a more adaptive character than in the Europeoids. In the Evenk vs. Europeoid girls, an increased activity both of glucocorticoid function of the adrenal glands and non-enzymatic antioxidant defense system was detected. In spite of the higher total cholesterol (TCh) level in women vs. girls in both ethnic groups, in the Evenk group TCh tended to decline. Changes in the antioxidant defense system of the Evenk women manifested themselves as an increased total antioxidant activity of blood vs. Europeoids as well as higher TCh and lower retinol levels vs. adolescent girls.     

The ability of flea species on the common vole from mountainous Dagestan to transmit and preserve the causative agent of plague

The infection ability and terms of preservation of plague microbe in fleas of common vole from Dagestan high-mountain plague focus (Frontopsylla causasica, Megabothris turbidus, Ctenophthalmus intermedius and Amphipsylla rossica) was studied experimentally. Block formation and transmission of the infection by F. caucasica and M. turbidus was observed. The transmission of plague microbe by Ct. intermedius fleas was first carried out. These species of fleas preserve the infection for a long time. Experiments with fleas of A. rossica yielded negative results.     

The structure of chromatin from the pigeon brain. II. Sedimentation analysis of oligonucleosome density

Compaction of pigeon brain and rat thymus chromatin differing in the length of the linker DNA has been studied by the method of velocity sedimentation. The dependence of sedimentation coefficients of oligonucleosomes on the number of nucleosomes in the chain in solution of different ionic strength (0.005-0.085) has been analyzed. The analyses of these dependences showed that the structure of oligonucleosomes of both cell types at low ionic conditions may be described by the model of a zig-zag-shaped nucleosomal chain. The process of compaction of the oligonucleosomes at higher ionic strength (0.045-0.085) proceeds similarly for brain and thymus chromatin. The formation of a superhelical structure is determined by the interaction of no less than 6 nucleosomes; the compactness of the structure is significantly increased when the number of nucleosomes in the chain exceeds 10. The ability of the brain oligonucleosomes to form a compact structure despite the short linker allow the suggestion that in brain short chromatin the DNA chain does not form two complete turns in the nucleosome. This provides necessary flexibility of brain chromatin.