Publications by authors named "Petrov R"

Experimental data obtained in this investigation indicate that the conjugation of Brucella protective antigen with a polymer carrier essentially increase the immunogenic properties of the antigen. Synthesized vaccinal preparations can be of interest for practical use, as these preparations, while inducing the development of intense immunity, do not impede the diagnosis of brucellosis by serological reactions. The comparative study of the conjugates of Brucella antigen with different carriers shows that the conjugated preparation obtained on the basis of modified dextran possesses high protective potency, which makes it possible to regard this carrier as very promising for further use.

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The protective properties of myelopeptides in the development of bacterial infection in mice and young pigs, caused by S. typhimurium 415, S. cholerae-suis 1422 and 370, have been studied.

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Evidence is presented for the existence of a relatively high-potential regulatory centre in the NAD-dependent hydrogenase from the hydrogen oxidizing bacterium Alcaligenes eutrophus Z1. Reduction of the hydrogenase to the redox potentials lower than -100 mV converts the enzyme into a catalytically active state that is remarkably stable to oxidants. Once activated, the enzyme does not loose its activity on intensive oxygenation for at least 3 hours.

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For the genetic analysis of the character of inheriting the immune response and the study of the possibility of immunoselection in astrakhan sheep, the test crossing of the previously selected and raised animals in different genetic combinations has been made. Regularities in inheriting the intensity of immune response in hybrids F2 and BC1 of astrakhan sheep, highly responsive to E. coli and Salmonella vaccines, confirm the dominant character of the capacity for intensive immune response.

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Bone marrow cells produce soluble mediators with structural and functional heterogeneity. They were found to stimulate antibody production at the peak of the immune response, owing to compounds of a peptide nature (Mr 2000-1300). Active material was isolated by means of gel chromatography and electrophoresis.

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The action of bone marrow low-molecular peptides (myelopeptides) was studied in the models of physiologic and pathologic pain. Myelopeptides were demonstrated to have a pronounced analgetic effect: they increased the latent period of the rats' response in the hot plate test (physiologic pain) and suppressed severe spinal pain syndrome induced by the generator of pathologically enhanced excitation in the dorsal horn of the spinal cord (pathologic pain). In the experiments with naloxone (an opiate receptor blocker) the data on the opiate properties of myelopeptides were further substantiated.

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A study was made of the content and functional activity of cell populations and subpopulations involved in the immune response at remote times after single sublethal irradiation (3 Gy). The exposed mice exhibited an earlier thymus involution and a decrease in the number of CFUc and antibody-producers per 10(6) karyocytes. The decrease in the antibody production was due to the reduced functional activity of B- and T-lymphocyte precursors and cooperative activity of T-helpers.

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Prior to the immunization of children aged 3-7 years with parotitis vaccine the state of their immune system was evaluated by the determination of the concentration of IgM, IgG and IgA, the ratio and absolute numbers of T- and B-lymphocytes, the intensity of the blast transformation of lymphocytes. This study revealed that the group of immunized children was essentially heterogeneous with respect to the state of their immune system: in 79.9% of the children all immunological characteristics were normal, in 20.

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The interaction of lymphocytes from mouse lymph nodes with allogeneic stem cells was studied using exogenous colony formation inhibition test. Dual nature of the interaction was revealed: great amounts of lymphocytes inhibited, while small amounts stimulated colony formation. This dependence holds true for macro- and microcolonies as well as for erythrocyte and granuloid microcolonies in the bone marrow during fixation on day 8 and 11 after cell mixture transplantation.

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Experiments in CBA (H-2k) and C57BL/6 (H-2b) strains of mice have shown (T,G)-A-L covalently bound to synthetic polyelectrolytes possessing immunoadjuvant effect to induce a pronounced antibody and cell-mediated immune response irrespective of murine genotype. When conjugated to the polyelectrolytes (T,G)-A-L was also found to acquire the properties of a highly immunogenic thymus-independent antigen. Thus, (T,G)-A-L-synthetic polyelectrolytes conjugates manifested the effects of highly immunogenic thymus-independent antigens inducing a potent Ir-1-independent immune response.

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An interpretive review of the theoretical and experimental data on the immunogenetic concept that "there are no strong and weak antigens, there are high and low responder genotypes," developed and upheld by the authors is presented. To achieve phenotypic correction (finding ways of turning genetically low responder individuals into high responder ones) the authors have developed complex antigens--artificial macromolecular complexes containing both the required antigenic determinants and adjuvant structures. Synthetic nonnatural carbohydrates and heterochain polyions with controlled structure (PAA, PVP, polyconidine quarternary salts) were shown to act as immunopotentiators, substituting the helper signal of T-cells.

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