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Biomedical subjects

L F Zykin

Publications and source records attributed to L F Zykin.

At least 19 recordsLinked to original sources
PubMed1991

[Radioimmunological analysis in studying the persistence of the plague antigen in the body of rodents and ectoparasites in natural foci in Siberia].

To study the persistence of Y. pestis capsular antigen, or fraction 1 (F1), in the body of less important plague carriers in the Mountain Altai and Transbaikal natural foci, as well as in experimentally infected ticks, the liquid-phase competitive radioimmunoassay (RIA) was used for the first time. In this study RIA showed, due to its sensitivity, doubtless advantages over traditional methods, such as the passive hemagglutination (PHA) test and the antibody neutralization (AN) test, and made it possible to detect F1 in picogram amounts. RIA revealed that F1 persisted in Siberian long-tailed gophers for up 14 months after the infection of the animals in diffusion chambers and for 7 months after their infection by subcutaneous injection. Experiments on Daurian pikas confirmed that, in comparison with the PHA and AN tests, RIA ensured fourfold effectiveness in the detection of antigen F1. The study of infected mites revealed that antigen F1 could be retained in them for more than a year and detected by RIA techniques in 10% of cases. The data obtained in this investigation indicate that the persistence of microorganisms should be studied mainly with the use of new-generation tests, and RIA, being one of the most sensitive techniques, deserves wide approval and introduction into the practical work of institutions intended for plague control.

Animals↗
PubMed1989

[Yersinia pestis L-forms in rodents and ectoparasites].

Y. pestis L-forms and bacterial forms persist in the body of great gerbils for 40 days. L-forms are poorly phagocytized and can persist in phagocytes for a long time. In guinea pigs immunized with vaccine EV, Y. pestis antigen could be detected till day 160. An unstable L-form was isolated from Ornithodoros mites 3 years after their experimental infection with Y. pestis. Bacterial forms persist in mites for 1-3 years. For 5 years Y. pestis antigen is regularly detected in a high percentage of mites.

Animals↗
PubMed1982

[Isolation of L-form of Yersinia pestis from wild rodents in an epizootic focus].

Four Y. pestis cultures with unbalanced growth and 15 Y. pestis cultures in unstable L-forms were isolated from wild rodents Rhombomys opimus in the vicinity of lake Balkhash. Morphologically they were mainly represented by granular, spheroplast-like and filiform elements. When stained with luminescent serum, they acquired specific fluorescence; in indirect hemagglutination they yielded positive result. Electron microscopy revealed the presence of morphological elements characteristic of the process of L-transformation. After subculturing reversion to rod-like forms was observed in 13 Y. pestis strains.

Animals↗
PubMed1978

[Enteropathogenicity of hemolysing El Tor Vibrios].

The authors studied the enteropathogenic properties of 11 strains of hemolysing E1 Tor vibrios, of which 8 in enteric administration to suckling rabbits caused no death of the animals, and 3 caused the animal death with the phenomena of diarrhea, but without any typical cholerogenicity syndrome. In case of administration with mucine the pathogenic properties were revealed in 6 strains more. Use of strains grown on media with starch for the infection led, in individual cases, to the manifestation of enteropathogenic properties. Consequently, the strains of hemolysing E1 for vibrios under study should be regarded as weakly virulent, and some--as avirulent ones.

Animals↗
PubMed1978

[El Tor vibrios with different enteropathogenicities].

The authors summed up the results of study of enteropathogenicity of 270 strains of the El Tor vibrios isolated the last 11 years. Over 2 000 nursling rabbits were used. El Tor vibrios were divided by their enteropathogenic properties into three categories: 1) the highly enteropathogenic (cholerogenic) ones causing the death of all the biotest nursling rabbits with a characteristic syndrome of cholerogenicity, and failing to lyse sheep erythrocytes; 2) enteropathogenic ones, causing death of some of the biotest animals without any characteristic cholerogenicity syndrome, but with the intestinal lesions; strains of this category are hemolytic; 3) nonenteropathogenic, causing no death of the animals even when their high doses are administered; these bibrios are hemolytic (cause lysis of sheep red blood cells).

Animals↗
PubMed1978

[Production of L forms of the plague microbe].

Experiments were conducted in vitro. The process of formation of unstable L-form cultures of Pasteurella pestis under the effect of penicillin was studied. A comparatively high frequency of this phenomenon in various strains was demonstrated. A possible role of the L-transformation process in the persistence of the causative agent in the organism of wild animals in endemic foci of infection is put forward.

Culture Media↗
PubMed1977

[Obtaining spheroplasts from the agents of glanders and melioidosis and separation of membrane structures from them].

Spheroplasts were obtained from the causative agents of glanders and melioidosis under the effect of lysozyme and antibiotics. In the capacity of an inducing agent lysozyme was effective in high concentration only (0.4%); preliminary washing and incubation in sucrose were necessary to obtain glanders spheroplasts. Of the antibiotics studied penicillin was more useful for obtaining melioidosis spheroplasts and ampicillin--for glanders spheroplasts. Membrane preparations were derived from the spheroplasts of glanders and melioidosis causative agents.

Ampicillin↗
PubMed1977

[Membrane antigens of the agents of glanders and melioidosis].

Double immunodiffusion in gel test was used to determine the antigenic composition of the preparations of membranes isolated from the lysozyme spheroplasts of glanders (strain No. 10230) and melioidosis (strain No. C-141) causative agents. The membranes of these microbes proved to contain antigens of cell walls, lipopolysaccharides and the thermolabile membrane antigen proper. A study of antimembrane sera in the agglutination and immunofluorescence tests demonstrated a heterogeneity of the glanders and melioidosis strains under study by the membrane thermolabile antigen.

Animals↗
PubMed1975

[Pathogenicity of nonagglutinating vibrios].

In studying the pathogenicity of nonagglutinating vibrios it was established that the majority of the strains isolated from the patients suffering from enteritis possessed enteropathogenic properties which were revealed in the trials on nursling rabbits and on the isolated intestinal loop a of an adult rabbit. In difference to the cholera vibryos, these microorganisms produced no typical cholerogenicity syndrome expressing, however, a number of enteropathogenic properties: caused diarrhea, overfilling of the intestine with fluid, etc. Autopsy showed a typical enterocolitis picture, confirmed by histological studies. Nonagglutinating vibrio cultures isolated from the water and from healthy persons possessed no enteropathogenic properties. An isolated intestinal loop of an adult rabbit proved to be the most sensitive experimental model.

Animals↗