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Biomedical subjects

L G Ivanova

Publications and source records attributed to L G Ivanova.

At least 19 recordsLinked to original sources
PubMed1997

[Fibrogenic and general toxic effects of copper and nickel sulfide ore dust (data for a hygienic evaluation)].

Experiments on acute and chronic inhalation of copper and nickel sulfide ore dust proved that the dust of rich ore, if compared with that of copper-bearing and impregnated ore, induces more marked toxic effects. Intratracheal administration of all the dust types, 50 mg, and inhalation of the high concentrations (102 mg/cu m in average) induced fibrogenic effects. The dust of rich ore induced more marked fibrogenic reaction in lungs, in 3 months after 6-month period of inhalations stopped that reaction disappeared. General toxic effects caused by the dust either of rich ore or impregnated ore were mild. Justifying the MAC requires consideration of possible carcinogenic effect.

Animals↗
PubMed1990

[Biological effect of brown coal dust in experimental studies].

For 4 months laboratory white rats were administered inhalations of polydisperse dusts of the brown coal from the Nazarovsky and Beregovsky coal deposits. Revealed were mainly identical, early marked reactions of the bronchi and lung system, which, judging from the quantitative indices, could be regarded as ++pre-fibrosis, as well as some signs of irritation on the cell elements, bronchi and lung vessels. The portion of lipids and general oxyproline in the dry lung substance in the sample group amounted to 16.3-17.2%, and 9.2% in the control group. The results in combination with the immune indices changes (complement, lysozyme, lymphocyte populations), histamine in the blood and non-specific shifts in the adrenal gland state and in the heart, proved the unfavourable action of ducts with low ash content and a minimal (no less than 1.3%) content of free silica dioxide. The reasons underlying brown coal's action in question are also thoroughly discussed.

Air Pollutants↗
PubMed1990

[The experimental morphofunctional changes in the body under the influence of dry environmental air].

Analysis of morphological changes in organs, tissues and cells of animal organisms (white rats) is presented in interrelations with shifts in somatometric parameters, fluctuations in water exchange induced by the decreased content of diluted liquid vapours in the air. On the basis of studies results the leading role of low humidity of the environment in the development of changes of the dehydration syndrome type has been proved.

Air↗
PubMed1990

[Biological effect of brown coal dust on the bronchopulmonary system and immunocompetent organs (experimental morphological study)].

Inhalation of the brown coal samples caused anthracosis with progressive growth in the postinhalation period and concomitant catarrhal-desquamative bronchitis, lymphoid tissue hyperplasia, emphysema, along with granuloma formation. The cases studied were marked with increased number and thickness of the argyrophile and reticuline fibres around the bronchi, vessels, granuloma and in the interalveolar septum. Changes were detected in the immunocompetent organs' state which might influence the homeostasis and the immune system. Complex cytomorphological investigation of the bronchopulmonary and immunocompetent systems can be applied to in biological studies of different aerosols.

Air Pollutants↗
PubMed1986

[Enhancing the effectiveness of microbiological nutrient media through balancing their content by an experimental analytical method].

The possibility of successful use of the analitico-experimental method for the development and improvement of balanced microbiological growth media, economical in composition, has been shown. By this method a new variant of the semisynthetic medium for growing Bordetella pertussis vaccine strain has been obtained, thus making it possible to achieve a considerable increase in the yield of the biomass without decreasing the immunogenicity of the culture. The use of the balanced medium in the production of vaccines may alone give the overall economic effect totalling 11000 roubles per 10000 liters.

Animals↗
PubMed1986

[Increase in the coefficient of component utilization by balancing the composition of the nutrient medium for growing pneumococci].

The possibility of using the experimental-analytical balance method (EABM) for development of balanced media, optimal and economic by their composition is shown. The method is based on the specific growth activity of the medium components and mathematical calculation of their concentrations. A balanced medium containing human placenta hydrolysate was developed. The medium has a high component consumption coefficient and provides maintenance of high levels of the pneumococcal culture biological properties such as growth, capsule formation, virulence and agglutinability. The quantities of nutrient yeast extract, cystine, glucose and sodium chloride in the balanced medium are 2, 18-20, 4-4.7 and 32-33 times lower respectively than those in the initial medium. The use of the balanced medium instead of the initial unbalanced one or instead of the meat medium based on the Hottinger broth will provide the total economy of 1010 or 2360-2580 roubles respectively per. 1000 liters of the medium. It is concluded that a wider use of this method in optimization of microbiological nutrient media in production of medical and biological preparations is promising.

Animals↗
PubMed1985

[Use of an experimental analytical method for equilibrating nutrient broths for Clostridium perfringens type A growth and toxin formation].

A successful attempt to use analytico-experimental approach to the evaluation of experimental data for the scientifically based calculation of the composition of complex culture media, intended for growing pathogenic microorganisms, has been made. The method is based on the evaluation of the specific growth-stimulating and toxin-forming activity of the components of a given culture medium, which are determined by the number of cells grown in the variants of the medium with the limited amount of one of its components. The use of the analytico-experimental balancing method makes it possible to develop culture media with the optimal composition ensuring the definite yield of the target product rather quickly and economically by experimenting on the minimal number of variants equal to the number of the components of the medium. The investigation carried out by means of the analytico-experimental method has revealed that on the basis of peptic serum albumin hydrolysate, pancreatic casein hydrolysate and fodder yeast extract, alongside the culture medium described in an earlier work and containing these components in the proportion 4:2:1, two other media, containing the above components in the proportion 2:4:1 and 3:4:2, can be obtained, these media providing the optimal conditions for, respectively, the toxin formation and growth of C. perfringens, type A.

Bacterial Toxins↗
PubMed1985

[Dissolved oxygen content in microbiological nutrient media].

The modification of a highly sensitive method for the determination of the concentration of dissolved oxygen in liquid culture media and in water is described. This modification permits the easy conversion of the relative readings of electrode membrane transducers for measuring the partial pressure of oxygen into the readings characterizing the absolute concentration of oxygen in the medium (mg/cu. dm). The content of dissolved oxygen in microbiological media and in water depends on the amount of dissolved mineral salts, amino acids and peptides (the products in incomplete proteolysis), as well as on temperature. The maximum level of oxygen saturation in liquid culture media at 37 degrees C is different for various types of media and constitutes their peculiar characteristic, determined in the process of aeration under experimental conditions.

Aerobiosis↗
PubMed1983

[Molecular structure and immunochemical properties of highly purified hemagglutinin from Clostridium botulinum type A].

A procedure for isolation of highly purified hemagglutinin from a toxic complex of culture filtrates of Cl. botulinum type A is described. This procedure includes precipitation with (NH4)2SO4, chromatography on Sephadex G-100, G-200 and DEAE-cellulose, specific adsorption on human erythrocytes and affinity chromatography. Using polyacrylamide gel electrophoresis, it was shown that hemagglutinin is a heteropolymeric protein consisting of a monomer (Mr 53 000) and a trimer (Mr 160 000). The monomer is made up of two subunits with Mr 13 000 and one subunit with Mr 27 000 covalently linked by SS-crosslinks. The number and nature of the SS-crosslinks and SH-groups in the protein molecule were determined and a hypothetical structural model of hemagglutinin was proposed. Using immunochemical analysis, it was shown that some (but not all) serological properties of the highly purified protein from Cl. botulinum type A and of its partially purified counterpart are similar to those of hemagglutinin from Cl. botulinum type B.

Chromatography, Affinity↗
PubMed1977

[Comparative immunochemical study of the hemagglutinins of Cl. botulinum A and B].

The authors demonstrated an incomplete indentity of Cl. botulinum hemagglutinins of types A and B in the double diffusion reaction in agar gel, and their difference by electrophoretic mobility. Some differences in the interaction of hemagglutinins A and B with human erythrocytes were found by the hemagglutination inhibition method; apparently, of the principal significance in the relization of the reaction of human erythrocyte hemagglutination with hemagglutinins of Cl. botulinum, types A and B, was the OH-group position in the C4 galactose of the mucopolysaccharides of the erythrocyte cell wall. Apart from C4, apparently, for hemagglutinin of types A of significance was the reactive capacity of C1 and C2 galactose atoms, whereas for hemagglutinin of type B--free OH-group in C2 galactose atom.

Agglutinins↗
PubMed1975

[Use of a synthetic medium for cultivating pathogenic anaerobes].

It was shown that a synthetic medium suggested by the authors earlier was useful for the growth and toxin formation of Cl. tetani, Cl. botulinum and Cl. perfringens, types B and E. A study of the character of growth and toxinogensis, microscopic examination of morphology of culture cells and results of passages showed the suggested synthetic medium to be of value; a possibility of its application for studying the nutrient requirements and the role of individual components of the nutrient media in the process of growth and toxinogenesis was also demonstrated.

Botulinum Toxins↗
PubMed1975

[Hemagglutinin specificity of Cl. botulinum types A, B, and F in reaction with erythrocytes of various animals].

The following differences were revealed in the haemagglutination reaction with the erythrocytes of man, sheep, rabbit, chicks and mice between the haemagglutinins of Cl. botulinum, types A, B and F, having a close affinity with one another: haemagglutinin of type A actively reacted with the erythrocytes of man, sheep, rabbit, rats and chicks; haemagglutinin of type B reacted only with the erythrocytes of man and rabbits; haemagglutinin of type F failed to react with any of the types of the erythrocytes tested; only with the use of erythrocytes treated with neuraminidase was it possible to establish the presence of haemagglutinin fraction in Cl. botulinum, type F. Treatment of human erythrocytes with neuraminidase and proteolytic enzymes caused a marked increase in the sensitivity of the haemagglutination reaction in haemagglutinins of Cl. botulinum, types A, B and F.

Agglutinins↗