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L M Isachkova

Publications and source records attributed to L M Isachkova.

27 records · Page 2Linked to original sources
PubMedDate not supplied

Experimental encephalitis in monkeys caused by the Powassan virus.

We have carried out a comparative study of the experimental infection of monkeys with the P-40 strain of the Powassen virus, isolated in the Primor'e Territory of the USSR, and with the Canadian prototype LB strain. The Powassan virus was found to be pathogenic for Macaca rhesus. The clinical and pathomorphological picture of the experimental encephalitis was studied, and the full identity of the infection produced in the monkeys by the P-40 strain and the Canadian LB strain of the Powassan virus was demonstrated. On electron microscopic examination of the central nervous system the virus was detected in the neurons, glial cells, and intercellular spaces. The virions of the strains studied have identical morphological parameters, being 37-45 nm in diameter and of spherical shape. The data obtained indicated a marked neurotropism of the virus. They will contribute to the elucidation of the role of the virus in the infection pathology of humans, i.e., in the differentiation of encephalitis cases not associated etiologically with the virus of the spring-summer tickborne encephalitis.

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PubMedDate not supplied

[Experimental tick-borne encephalitis in golden hamsters treated with specific immunotherapy].

Efficiency of various protocols of specific immunoglobulin treatment was evaluated in golden hamsters inoculated with two Far Eastern tick-borne encephalitis (TBE) strains. After a low therapeutic dose (0.1 ml) of immunoglobulin, corresponding to total dose (60 ml) per course, all parameters (survival, immunogenicity, pathomorphology of the brain) deteriorated in animals infected with both strains. A higher dose (0.2 ml) corresponding to total dose of 120 ml notably improved all the studied parameters. The efficiency of specific immunoglobulin depends on the clinical and pathogenetic characteristics of TBE, determined by the properties of TBE strains. The results validate therapy and prevention of TBE by high-titer immunoglobulin in adequate total dose, monitored by blood analyses for TBE antigen and evaluations of the time course of IgM antibodies.

Animals↗
PubMedDate not supplied

[Influence of temperature on the variability of Listeria monocytogenes in the course of its prolonged existence in soil-packed water-circulating columns].

The capacity of L. monocytogenes for prolonged existence in the soil at different temperatures (18-20 degrees C and 6-8 degrees C) has been shown. The viability of these bacteria in the soil depends both on their properties and the temperature factor. Low temperatures (6-8 degrees C) ensure, on the whole, the stable preservation of the biological properties of the bacteria. More pronounced variability of L. monocytogenes at a temperature of 18-20 degrees C is an adaptive property, ensuring high ecological plasticity of the bacteria and their prolonged existence in the soil.

Acclimatization↗
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[Pathomorphology of experimental infection caused by powassan virus isolated in the Primorskiĭ Territory].

Pathomorphology of the infection caused by Powassan virus strains isolated in the Primorsky Kray was studied in white mice. The central nervous system of the animals sacrificed in the time course of the infectious process was studied by light and luminescent microscopy. Severe diffuse inflammatory-degenerative changes were found in the brain and spinal cord. Immunofluorescence revealed cytoplasmic localization of the virus antigen in neurons, glial and connective tissue cells.

Animals↗
PubMedDate not supplied

[Role of Powassan virus in the etiological structure of tick-borne encephalitis in the Primorsky Kray].

Composite studies conducted annually in the Primorsky kray showed the tick-borne encephalitis virus to play the main etiological role in the group of encephalites with the spring-summer incidence. In 1976--1978, virological studies of 69 cases of the disease yielded 11 strains of tick-borne encephalitis virus. In 1978, from the blood of clinically normal woman after a tick bite strain 555 was first isolated which was identified as Powassan virus, and antigenemia was observed for 53 days using the fluorescent antibody technique. In the same period, serological examinations of the blood sera from 117 patients demonstrated antibody to tick-borne encephalitis virus in 69.2%, to Powassan virus in 4,3% and to both viruses simultaneously in 4.3%. Besides, antibody to tick-borne encephalitis virus, Powassan virus and both viruses simultaneously was found in patients with progredient forms of tick-borne encephalitis and in subjects with the history of tick attachment.

Antibodies, Viral↗
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[Pathogenetic criteria for evaluating the virulence of tick-borne encephalitis strains isolated in the southern part of the Far East].

A comparative virological, immunological, and pathohistological study of 5 tick-borne encephalitis (TBE) strains differing by virulence was carried out in golden hamsters. The authors characterize the TBE virus pathogenicity sign, denoted as Pmaic genetic marker (pathogenicity for hamsters at intracerebral inoculation), which helps understand the essence of immunopathogenetic mechanisms of the TBE infectious process in man.

Animals↗
PubMedDate not supplied

[Yersinia L-transformation in experimental pseudotuberculosis].

An experiment on guinea pigs infected with virulent Y. pseudotuberculosis has revealed for the first time that in the host body Yersinia cells undergo ultrastructural changes, characteristic of L-transformation. These changes are manifested by damages in the cell wall and peptidoglycan layer of bacteria, dramatic expansion of the peri-plasmatic space, appearance of spheroplast bacterial cells. Myelin-like structures are formed around dead bacteria. These changes reveal one of the possible mechanisms which may render Yersinia harmless in convalescent patients, as well as contribute to the development of relapses of Y. pseudotuberculosis infection.

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