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Biomedical subjects

I N Kokorin

Publications and source records attributed to I N Kokorin.

At least 19 recordsLinked to original sources
PubMed1992

Persistence of Rickettsia prowazekii in cotton rat macrophage cultures.

Rickettsia prowazekii is able to multiply and persist for a long time in cotton rat macrophage culture (29-days observation period). Electron microscopic studies showed that the structure of Rickettsiae remained intact at different intervals post-inoculation (p.i.). In the course of persistence Rickettsiae revealed a reduced capacity to infect chick embryos and guinea pigs, however, the infectious agent could be isolated at all stages of persistence of cultured cells such as fibroblasts of the guinea pig embryo, macrophages of intact cotton rats.

Animals↗
PubMed1986

Thymus-independent antibody production to the antigen of Rickettsia prowazekii.

Antibody production has been studied in cotton B-rats and in CBA B-mice during immunization with chemical typhus vaccine (CTV) and during infection with Rickettsia prowazekii. Studies of the immune response to rickettsial antigen in T-deficient animals have shown a high immunogenicity of CTV and independence of antibody production on T-lymphocytes. Active antibody synthesis was also observed in B-rats and B-mice during Rickettsia prowazekii infection. The absence of T-lymphocyte dependence in experimental animals was tested by administration of sheep red blood cells (SRBC).

Animals↗
PubMed1986

Peculiarities of Rickettsia prowazekii in the cell culture as revealed by cryoultramicrotomy.

Ultrastructure of Rickettsia prowazekii has been followed in L-929 cells 4 days post-infection (p.i.) by cryoultramicrotomy. Groups of rickettsiae were present in the cytoplasm outside of vacuoles forming microcolonies. The size of rickettsiae amounted to 400 X 700 nm, the average thickness of the cell wall was 5 nm, that of periplasmic space and cytoplasmic membrane 14 and 6 nm, respectively. Within intracytoplasmic colonies the rickettsiae were tightly packed and their cell walls were closely adjacent to each other. No halo or capsule-like coating around them was detected. No ultrastructural details were observed in the light translucent spaces between cells. Marginal rickettsiae of the microcolonies were often in close contact with the host cell mitochondria.

Animals↗
PubMed1986

[Immunogenicity of a chemical typhus vaccine and of a corpuscular radioantigen obtained from Rickettsia prowazekii].

The protective activity of chemical typhus vaccine and R. prowazekii corpuscular radioantigen (CRA) was studied. Guinea pigs were immunized with doses of 32 and 48 antigenic units. Antibody production was assayed in the complement fixation test. On days 7, 15, 21, 30 and 60 after immunization the animals were challenged with R. prowazekii introduced in an amount of 10(5) minimum embryonal infective doses (MEID). On day 30 some of the animals were challenged with 10(3) MEID of R. typhi. The results demonstrated that both preparations were highly immunogenic and capable of protecting most of the animals from 10(5) MEID of R. prowazekii. Immunity developed earlier after immunization with CRA. The guinea pigs immunized with CRA, purified in percoll density gradient, and challenged with 10(3) MEID of R. typhi on day 30 showed a high level of cross immunity. In all control animals high fever and periorchitis were observed.

Animals↗
PubMed1986

[Importance of T-lymphocytes in antibody production in experimental typhus infection].

The study of antibody production in cotton rats infected with Rickettsia prowazekii B and TB has revealed that R. prowazekii antigens, inducing the production of antibodies determined in the complement fixation, indirect hemolysis, and passive hemagglutination tests, are T-independent. The study of the nonspecific reactivity of T-lymphocytes in cotton rats infected with R. prowazekii TB has indicated that in case of the prolonged persistence of the infective agent in the animals no secondary immune deficiency develops.

Animals↗
PubMed1985

Histological changes in mouse liver and spleen caused by different Coxiella burnetii antigenic preparations.

The effect was examined on mouse liver and spleen (inbred line A) of intraperitoneal (i.p.) inoculation of phase I Coxiella burnetii (C.b.) cells either untreated or treated with chloroform-methanol (CM) mixture in comparison to the trichloracetic acid extract (TCAE) from phase I C.b.) cells. The phase I C.b. cells were highly toxic as manifested by marked hepatosplenomegaly accompanied with hyperplastic, degenerative and necrotic changes in the liver. By contrast, phase I CM--treated C.b. cells and TCAE were nontoxic as evidenced by the absence of any distinct pathological changes in mouse viscera.

Animals↗
PubMed1985

[Use of the immunofluorescence reaction for evaluating the immunological transformation in those inoculated with a chemical typhus vaccine].

The results of the serological examination of persons immunized with chemical typhus vaccine (CTV) are presented. The examination was carried out by means of the complement fixation test (CFT), the passive hemagglutination test (PHAT), the toxin neutralization test (TNT) and the immunofluorescence test (IFT). The acetone-fixed live culture of Rickettsia prowazekii, strain Breinl, served as antigen in IFT. If persons immunized with CTV showed positive titers in CFT, TNT and PHAT, the results of IFT were highly correlated with the CFT titers. In 6-12 months after immunization with CTV the titers of CFT, TNT and PHAT became negative, while the IFT titers remained positive for several subsequent years.

Antibodies, Bacterial↗
PubMed1982

Role of T lymphocytes in Rickettsia conorii infection.

Adoptive transfer of T lymphocytes harvested from spleen of Rickettsia conorii-infected DBA/2 mice to intact and cyclophosphamide- (CPA-) pretreated syngeneic mice protected the latter from lethal infection caused by R, conorii. Protection from infection was not observed in recipient mice given immune serum or B lymphocytes and macrophages from the spleens of convalescent mice. The protective effect was most pronounced after intravenous transfer of lymphocytes obtained from donor mice on day 14 post infection. Lethal infection was not prevented by transfer of lymphocytes harvested on day 50 p. i., although at this interval the donor mice were still resistant to reinfection with F. conorii.

Animals↗
PubMed1981

[Histopathological characteristics of Legionella pneumophila infection in man and guinea pigs].

The current histopathological aspects of legionnaires' disease, a newly discovered acute feverish disease accompanied by severe rapidly progressive pneumonias with 20% mortality are reviewed. Epidemic and sporadic cases of legionnaires' disease occurred both in the United States and many countries of Europe. The gross and microscopic pathology of autopsy specimens from patients with legionnaires' disease and pathological findings in guinea pigs inoculated intraperitoneally with Legionella pneumophilla are discussed. Some methods for isolation of specimens for laboratory diagnosis in severe pneumonias suspect for legionnaires' disease are recommended.

Animals↗
PubMed1980

Role of macrophages in infection with Rickettsia conorii.

Macrophages obtained from the abdominal cavities and spleens of DBA/2 mice and guinea pigs convalescent after Rickettsia conorii infection digested the rickettsiae in vitro more actively than those from uninfected animals. The activation of macrophages was manifested by their capacity to inhibit replication of the rickettsiae and to digest them as well as by their resistance to the toxic effect of rickettsiae. Visual observations and bioassays showed that a portion of the rickettsial population survived in the culture producing no toxic effect on the cells which could be readily passaged.

Animals↗
PubMed1980

Interaction of rickettsiae with haemocytes of Alveonasus lahorensis ticks.

The development of different rickettsial species (Rickettsia sibirica, R. conorii, R. acari and coxiella burnetii) in haemocytes of Alveonasus lahorensis ticks was compared by viral observations and time-lapse cine-micrography. The interaction of different rickettsial species with the haemocytes in vitro had specific characteristic features and reflected the pattern of interaction of the rickettsiae with tick cells in vivo.

Animals↗
PubMed1978

[Microcinematographic study of pancreatic islet cells from fetal cattle].

The growth characteristics of pancreatic islet cell cultures of bovine fetuses were investigated by the method of time-lapse cinemicrography. These monolayer cultures consisted of epithelial cells only. Under the influenc of high glucose concentration in the growth medium (up to 300 mg per 100 ml) there occurred an activation of mitochondrial apparatus of the islet cells, stimulation of cytogranulokinesis, and intensification of accumulation of the secretory granules with the subsequent degranulation of the islet cells. These data were compared with the results of cytological control of fixed and stained culture.

Animals↗
PubMed1978

Differences in the susceptibility of mouse lines to the rickettsial pox agent.

A definite correlation between the susceptibility of spleen macrophage cultures derived from a highly susceptible mouse line (C57Bl/6) and a line with low susceptibility (DBA/2) and the susceptibility of these mouse lines to infection with Rickettsia acari was established. Intensive replication of the rickettsiae in cultures from highly susceptible animals caused marked disorders in cell metabolism and eventually death of the culture. Cell cultures derived from resistant mice gradually eliminated the rickettsiae by intracellular digestion; necrobiotic changes in them were insignificant.

Animals↗