The mechanisms maintaining epidemic foci of leptospirosis]

24,419 samples of blood serum, collected in the Azerbaijan SSR among different professional groups of the population, have been tested for leptospirosis. The comparison of the results with those obtained in the natural foci of leptospirosis and in the foci of this infection appearing as a consequence of human activities has made it possible to come to the conclusion that the epidemic foci of leptospirosis are maintained due to the existence of foci among cattle. The cases of contamination among persons professionally linked with large cattle breeding complexes have been found to exceed those among persons working at farms of a nonindustrial type.     

Self-maintenance of induced bone tissue]

The capacity for self-maintenance of the bone marrow osteogenic precursor cells from the skeletal bones and from the bones induced by implantation of decalcified bone matrix is compared. Transplantation in diffusion chambers is employed as the test system. Osteogenesis in the bone marrow transplants isolated from the skeletal bone lasts several months, whereas osteogenesis in the bone marrow transplants isolated from induced bone stops after the second month. Fibroblasts arising in the monolayer cultures of the skeletal bone marrow retained their osteogenic potencies after repeated passages. On the contrary, fibroblasts from the monolayer cultures of induced bone marrow lost their osteogenic capacity after the second passage. Thus, contrary to osteogenic precursors of the skeletal bone, osteogenic precursors of induced bone tissue had a very limited self-maintaining capacity after the cessation of induction.     

The self-maintenance of natural foci of leptospirosis

The specificity of infection of individual species of small mammals with definite serogroups of leptospires has been shown. The intensity of the epizootic process has been found to depend on the number of animals in the population. The mechanisms of the self-regulation of the epizootic process in natural foci are explained.     

Self-maintenance of migrating hematopoietic stem cells]

Decreased self-maintenance ability of the migrating stem cells (CFU) from the peripheral blood or ectopic focus of hemopoiesis in comparison to the settled bone marrow CFU, as measured by the spleen colony method or by means of chromosomal markers, has been studied. The competence for myeloid and lymphoid differentiation was essentially the same for migrating and settled stem cells.     

Natural foci of leptospirosis in Moscow in 1995 - 2004

The article deals with the results of the 10-year study of the synanthropic urban foci of leptospirosis on the territory of Moscow. Information on the manifestation of the activity of the foci under study, rodents serving as the reservoir of infection in these foci, the etiological structure of the leptospires among these rodents, the state of leptospirosis morbidity among humans is presented.     

Comparative study of the immunoglobulin content in persons from leptospirosis foci in different geographical zones of the RSFSR]

The authors carried out a comparative study of the content of serum immunoglobulins in persons from the leptospirosis foci of various geographical zones of the RSFSR: European part--the Centre (Moscow and Ryazan regions), the South (Checheno-Ingush ASSR and Krasnodar Territory), and Western Siberia (Altai territory), Leptospira of serological group Pomona, Grippotyphosa, and Hbedomadis served as the causative agents of the diseases. It appeared that the annual course of the climatic factors acted equally (inhibitory action) on the immuno-globulin metabolism in the residents of temperate and southern zones of the RSFSR at the warm period of the year (May-September), and in the Western Siberia- in winter. However, irrespective of the time of the year, the level of immunoglobulins G and A was greater in the residents of Western Siberia than in the native population of the European part. There proved to be no correlation between the levels of leptospirosis seropositivity in the foci of infection under study and the serum immunoglobulins in local residents of various geographical zones.     

Natural foci of leptospirosis on the territory of Moscow in 1995 - 2004

The results of ten-year observations of the natural foci of leptospirosis on the territory of Moscow are presented. Information on the foci, the main species of small mammals (the reservours of the infection), the etiological structure of leptospires, circulating among rodents and insectivores, is given.     

Hyperplastic foci in chemical carcinogenesis]

Morphological, histochemical and biochemical perculiarities of liver hyperplastic nodules induced by different chemical carcinogens are regarded. The presence of basophylic atypical cells in the hyperplastic nodules, the possibility of transplantation of some nodules, the irreversibility of some morphological and biochemical lesions in these allows to designate hyperplastic nodules as a neoplasm. Enzyme and isozyme patterns in hyperplastic vesicles, the appearance of alpha-fetoprotein in these, and some other metabolic findings suggest biochemical disdifferentiation occurring in the vesicles. These findings suggest that cells of hyperplastic nodules are intermediate between normal and malignant cells in the course of neoplastic transformation.