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Biomedical subjects

K Yagami

Publications and source records attributed to K Yagami.

83 records · Page 5Linked to original sources
PubMed1986

Pathogenesis of haemagglutinating encephalomyelitis virus (HEV) in mice experimentally infected by different routes.

Three-day-old suckling mice inoculated intracerebrally (i.c.) with the 67N strain of haemagglutinating encephalomyelitis virus (HEV) showed nervous signs and died. The virus was passaged 10 times in suckling mice and was designated the MB-67N strain. The pathogenesis of MB-67N was studied with various ages of mice and inoculation routes. All mice inoculated i.c. with a large dose of virus died regardless of age, although a smaller dose caused fatal infection only in suckling mice. By intranasal, intraperitoneal and subcutaneous inoculation, the virus also killed suckling mice under 16 days old, but not older mice, even with a large dose. The susceptibility of mice for the MB-67N strain was influenced by age and inoculation routes. High titres of virus were re-isolated from the brain of diseased mice after inoculation by any route, but not from other organs. Histologically, numerous areas of severe focal necrosis were produced in the cerebral cortex. Specific immuno-fluorescence and numerous viral particles were found in the cytoplasm of nerve cells by immuno-fluorescence staining and electron microscopy. These findings indicate that the MB-67N propagates mainly in the central nervous system and nerve cells serve as a main target of virus replication.

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PubMed1985

Serologic and virologic surveys on feline herpesvirus and feline calicivirus infections in cats for experimental use.

Serologic survey and virus isolation of feline herpesvirus (FHV) and feline calicivirus (FCV) were performed on cats used for research at the Laboratory Animal Research Centre, The University of Tsukuba, over the period from 1978 to 1981. Of the 507 mature and immature cats, 4 months old or older, 102 (20.1%) had HI antibody against FHV and 412 (81.3%) SN antibody against FCV. Some 23 (16.2%) and 76 (53.5%) kittens among 142 younger than 4 months had antibodies against FHV and FCV, respectively. Both the antibodies in kittens were considered to be maternally derived. The FCV antibody rate was especially high in cats weighing 2.5 kg (males) and 2.0 kg (females) or more, which were regarded as 8 to 10 months of age. An attempt was made to isolate the viruses from the oropharynx and conjunctiva of clinically healthy mature or immature cats and kittens. As the result, either one or both of the viruses were isolated from 31 of 75 mature and immature cats, and isolation rates of FHV and FCV were 6.7% and 36.0%, respectively. On the other hand, no virus was detectable in 16 kittens.

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PubMed1985

Evaluation of tri-combinant vaccine for feline herpesvirus, calicivirus and panleukopenia virus infections in Japanese native cats.

Tri-combinant vaccine consisting of attenuated feline herpesvirus (FHV) and feline calicivirus (FCV) and inactivated feline panleukopenia virus (FPLV), were evaluated for safety and efficacy, using Japanese native cats and the viral strains isolated in Japan. Thirty-eight 9- to 12-week-old kittens were inoculated intramuscularly and subcutaneously with the vaccine. Consequently, no adverse reaction was found, and protective efficacy was confirmed by challenge tests with the virulent strains of each virus. Serum-neutralizing antibodies against FCV and FPLV were maintained for at least one year after vaccination, whereas antibody against FHV disappeared in two cases at 24 weeks after vaccination. Application of this vaccine seemed effective for control of feline viral disease in cats for experimental use.

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PubMed1983

Interferon induction in Toxoplasma gondii infected mice.

Regular interferon (IFN-R) activity was detected in the serum of mice within 24 h after intraperitoneal inoculation with Toxoplasma gondii or Toxoplasma lysate antigen (TLA). Mice which survived from subchronic infection (14-28 days post infection) when injected with TLA showed the appearance of gamma interferon (IFN-r) activity in their sera within 6 h after injection.

Animals↗
PubMed1982

Studies on viral respiratory disease in laboratory cats. I. Isolation of feline herpesvirus and choice of proper disinfectant.

In the laboratory cat colony consisted of 14 Korats and 8 Japanese native cats, the disease characterized by upper respiratory signs occurred. Seven cytopathogenic agents were isolated from the oropharyngeal swabs and necropsy materials of affected cats by means of inoculation to primary feline kidney cell cultures. One of the isolates (KS-1 strain) was identical with feline herpesvirus (FHV), and appeared to be a causal agent of the trouble. Properties of the KS-1 strain were in general agreement with the known strains of FHV. Serologic examination and clinical analysis suggested that Japanese native cats became carriers, re-excreted the virus and spread it to susceptible cats. Virucidal activities of several disinfectants against FHV, comparing with a feline calicivirus (FCV), were studied and the following conclusions reached: 1) Sodium hypochlorite, iodine complex, benzethonium chloride and chlorhexidine were effective against FHV at commonly used concentrations. 2) Among chemicals tested sodium hypochlorite was most effective against FCV and followed by iodine complex. 3) Benzethonium chloride and chlorhexidine had little efficacy against FCV at commonly used doses.

Animals↗
PubMed1982

Activation and augmentation of guinea pig macrophages with streptococcal preparation OK-432 and stimulated spleen cell products.

A mechanism of macrophage activation by a streptococcal preparation (OK-432) was studied. Peritoneal exudate macrophages from normal guinea pigs treated in vitro with OK-432 were activated, manifesting increased glucose consumption, increased spreading, and morphological alterations under scanning electron microscopy. Macrophages showed extensive spreading within 1 hr after OK-432 treatment; they then became rounded with characteristic ruffles in their surfaces after 6 hr of treatment. Highly purified macrophages were activated as effectively as a crude macrophage preparation, suggesting that the macrophage activation resulted from a direct interaction between macrophages and OK-432. However, when spleen cells were treated with OK-432, a factor(s) capable of activating macrophages was produced in the culture supernatant. Spleen macrophage-rich preparation was found to release the factor(s) upon stimulation with OK-432, but this did not occur with the lymphocyte-or granulocyte-rich preparations. These results indicate that OK-432 not only activates macrophages by direct interaction without lymphokine participation, but also augments the activation by affecting spleen cells, probably macrophages, in such a way as to produce monokines.

Animals↗
PubMed1981

Protective reaction against malaria infection in mice sensitized with Frozen-thawed toxoplasma tachyzoites.

Mice sensitized with frozen-thawed Toxoplasma antigen emulsified in Freund's Incomplete Adjuvant (FIA) showed high resistance against Plasmodium berghei infection, but not in mice sensitized with paraformaldehyde-fixed. Toxoplasma or saline plus FIA. However, mice which survived from malaria infection did not show any protective reaction against the RH strain inoculation. Furthermore, an immune interferon activity was detected in the supernatant of the spleen cells collected from the mice sensitized with frozen-thawed Toxoplasma and cultured with the specific antigen, however, no Toxoplasma growth inhibitory factor (Toxo-GIF) was found in the same supernatant of lymphokines. From these results, it is suggested strongly that frozen-thawed Toxoplasma antigen could confer nonspecific resistance in mice against Plasmodium infection.

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