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Biomedical subjects

F Nishikawa

Publications and source records attributed to F Nishikawa.

64 records · Page 4Linked to original sources

Nonspecific stimulation of host defense by Corynebacterium kutscheri. I. Antitumor effect.

The effect of local injection of formalin-killed Corynebacterium kutscheri (FK.CK) on mouse survival after the intraperitoneal inoculation of Ehrlich ascites carcinoma in outbred ddY mice or P388 leukemia cells in inbred CDF1 mice was investigated. Treatment of mice in the dose range of greater than 10(6) organisms per mouse conferred the substantial protection on both mice. The initial phase of antitumor effect consisted of the marked increase in the number of peritoneal exudate cells and the enhanced cytotoxicity of peritoneal exudate cells. The Winn assay disclosed that antitumor effect by which tumor-burden mice could survive was attributable to nonadherent splenocytes whose activity was impaired by treatment with anti-T cell serum and complement. A single injection of FK.CK induced the cytotoxicity to three different murine tumor cells in serum of treated mice without a boosting injection of endotoxin. Furthermore, the generation of effector cells and serum cytotoxicity seemed to be paralleled by that of the delayed-type hypersensitivity to this organism. Thus, the antitumor resistance induced by C. kutscheri is considered to be in part T cell mediated.

Animals↗

Characterization of simian viruses isolated from wild cynomolgus monkeys.

Twenty three strains of simian viruses isolated from nasopharyngeal swabs and respiratory tissues of cynomolgus monkeys showing mild symptoms of respiratory disorders were classified into three groups by their biological, serological and morphological characteristics. Thirteen strains classified as group 1 were judged to be enteroviruses. Four strains of group 2 and six strains of group 3 were identified as simian adenoviruses. Yields of the ten simian adenoviruses of groups 2 and 3 were compared in three continuous cell lines after several serial passages.

Adenoviridae↗

Characteristics of Murayama virus in various cell cultures and laboratory animals.

Some biological properties of Murayama virus, a new paramyxovirus, were studied. The virus grew well in primary monkey kidney cells as well as embryonated eggs, while the virus yields in primary chick embryo and BHK-21 cells were much lower. The infected BHK-21 cells formed large syncytia and showed typical hemadsorption, but did not produce any detectable amount of hemagglutinin in the culture fluid. The virus yields were very low in Vero. LLC-MK2 and MDCK cells at first passages. The addition of trypsin to the medium enhanced virus growth in Vero and LLC-MK2 but not in MDCK cells. Cell fusion activity of the virus was observed in Molt-4 cells. Hemolytic activity was enhanced by freeze-thawing. Several species of mammals and birds were susceptible to experimental infections with the virus as evidenced by seroconversion and positive virus isolation without showing any clinical signs.

Animals↗

A new Paramyxovirus isolated from cynomolgus monkeys.

A new virus was isolated from cynomolgus monkeys for laboratory use imported from Indonesia in July, 1973. The virus agglutinated erythrocytes of some avian and mammalian species and hemolyzed chick erythrocytes. The virus was eluted from the surface of chick red blood cells by its neuraminidase activity. The virus was inactivated by ether; its nucleic acid was RNA. On electron micrographs, the particles varied from 250 to 400 nm in diameter, being covered with envelopes in which the surface projections were embedded. The diameter of inner helical structure was about 18 nm. These observations indicate that the virus belongs to a group of paramyxoviruses. On the basis of serological examinations, this virus can be identified as a new virus having some relations with Yucaipa or Bangore viruses. This virus is designated as "Murayama virus" from the name of the place where it was isolated.

Animals↗

Studies on the interaction between coxsackievirus A9 and HeLa cells. I. Plaque-forming ability of coxsackievirus A9 in HeLa cell cultures.

Most of the coxsackievirus A9 (CA 9 virus) including the prototype strain formed plaques in HeLa cell monolayers under agar overlay, although they showed little or no cytopathogenicity under fluid medium. These viruses were isolated or passaged in primary cynomolgus monkey kidney (MK) cell cultures, and the infectivity of any strain in terms of plaque-forming units was much higher in MK cells than in HeLa cells, even after plaque purification of the virus in HeLa cell cultures. CA 9 virus contained in the original throat swabs as well as some clones obtained by plaque purification in MK cells failed to form plaques in HeLa cells, but virus preparations obtained after several undiluted passages through MK cells included plaque-formers in HeLa cells, suggesting that such plaque (HeLa)-forming viruses may have developed at a certain rate during multiplication of the original non-plaque (HeLa)-forming virus population in MK cells. Out of four lines of HeLa cells examined, two, including a clonal line S3, failed to support plaque formation by CA 9 virus.

Agar↗