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Biomedical subjects

A Oya

Publications and source records attributed to A Oya.

At least 91 records · Page 5Linked to original sources
PubMed1981

Antigenic and genetic analysis of A/Hong Kong (H3N2) influenza viruses isolated from swine and man.

Two H3N2 strains of influenza A virus isolated from pigs in Japan and Thailand were characterized antigenically and genetically. A/swine/Wadayama/5/69 (isolated in Japan in 1969) was antigenically similar to a human strain, A/Aichi/2/68, while A/swine/Bangkok/9/78 (a swine isolate in Thailand) was closely related to A/Bangkok/36/78, a contemporary human isolate. Gel electrophoresis and oligonucleotide mapping of the virus RNA revealed genetic similarity between A/swine/Wadayama/5/69 and A/Aichi/2/68, and between A/swine/Bangkok/9/78 and A/Bangkok/36/78, suggesting the derivation of swine H3N2 strains from contemporary human strains.

Antigens, Viral↗
PubMed1981

[An inhalation apparatus for respiratory infections in small laboratory animals (author's transl)].

A dynamic inhalation apparatus with following characteristics was deviced for experimental infections in small laboratory animals. Nebulized bacterial aerosols were blown against a stainless steel ball of 15 mm diameter which was located at 31 mm distance from the nebulizer and smaller-particle aerosols were wafted up via air stream of 60 liter per minute introducing into an inhalation chamber. Thus 5.7 to 6.7 micrometers particles in average were homogeneously distributed in the chamber and inhaled by animals to their lungs with little individual variations in number of bacteria. The exhausted air was sterilized through HEPA filter after heated at 300 degrees C for 10 seconds, and negative inside pressure of the apparatus produced by the suction system served as a safeguard against aerosol leak.

Aerosols↗
PubMed1981

Isolation and serological characterization of influenza A virus from a pig in Thailand.

A hemagglutinating agent was isolated from a pig in Thailand in 1978 during the early febrile stage of an influenza-like illness and identified as influenza A virus. The isolate contained hemagglutinin and neuraminidase antigens that were antigenically indistinguishable from those of A/Tokyo/6/73 (H3N2), a Port Chalmers-like strain isolated in Japan. Serological tests also indicated that prevalence of H3N2 virus in the swine population in Thailand.

Animals↗
PubMed1981

A single serum dilution method for the quantitation of neutralizing antibodies to varicella-zoster virus.

A one-point serum dilution method for determination of neutralizing antibody in human sera to varicella-zoster (V-Z) virus instead of the serial serum dilution method was investigated. Focus counting was performed under a microscope on day 5 to 6 after inoculation of V-Z virus into 6-well plastic trays in which human embryonic lung cells were grown. A table was constructed to estimate the ND50 titers by the per cent reduction of the focus count from the control at only one dilution of test sera. The estimated ND50 values agreed well with those determined by the serial serum dilution method. Test sera showed a slight nonspecific reactivity at low serum dilutions, but reliable results could usually be obtained at a serum dilution of 1:8 or more. This method, which saves materials and labor, was applied to the quantification of neutralizing antibody against V-Z virus in human sera with satisfactory accuracy and reproducibility.

Adolescent↗
PubMed1981

Experimental intrauterine infection of akabane virus. Pathological studies of skeletal muscles and central nervous system of newborn hamsters with relevances to the Fukuyama type congenital muscular dystrophy.

A vertical infection system in hamsters produced by inoculating with Akabane virus was established as an experimental model of congenital muscular dystrophy (Fukuyama type) (FCMD) and arthrogryposis multiplex congenita (AMC) in humans. Swollen fetuses, mummified fetuses, arthrogryposis and cranial deformities were produced in 13 of 415 newborn hamsters inoculated transplacentally (3.1%). The incidence was significantly higher than that in the control group (p less than 0.05). Eight cases presenting apparent abnormalities were examined histologically and virologically. Pictures of skeletal muscles showing such immature features as chains of internal nuclei and myotubular muscle fibers were demonstrated in all cases. In addition, perivascular infiltration of small round cells and thickening of vascular walls were seen in 5 cases, while myogenic changes such as broken myofibrils, small muscle fibers and changes in fiber size were observed in 6 cases. In the anterior horn of the spinal cord, swelling and loss of nuclei and cell matrices were noticed in 4 cases. In the cerebral cortex, disarrangement of cell layers, edematous changes and loss of nerve cells were revealed in 5 cases. In 4 cases virus particles were found on electron microscopy in the cerebral cortex. The authors considered that this experimental system of intrauterine viral infection would be useful for the etiological study of FCMD and AMC in humans in which not only skeletal muscles but also the central nervous system is affected congenitally.

Animals↗
PubMed1979

Some characteristics of persistent rabies virus infection in cell cultures.

Fixed rabies virus strain M512 was shown to propagate in BHK cell cultures without interfering with cell growth. Virus specific antigen was detected in the cytoplasm of cells by immunofluorescence technique. A small amount of virus was detected in the supernatant fluid throughout a series of subcultures. The infectivity of the intracellular virus was not affected by the addition of antirabies serum in culture fluid through the extracellular spread of virus was inhibited at the 40th transfer of the infected BHK Cells suggesting the establishment of the persistent M512 infection. Ninety five percent or more cells after cloning from persistently infected cells possessed viral antigen. Based on cytopathic effect, BHK-M512 cells were resistant to superinfection with the homologous virus but were susceptible to the heterologous virus. Interferon was not detected in BHK-M512 cell cultures. The serially passaged BHK-M512 virus gradually decreased the virulence for mice after 40th subculture.

Animals↗
PubMed1978

Association of virus specific replicative ribonucleic acid with nuclear membrane in chick embryo cells infected with japanese encephalitis virus.

Using high resolution electron microscopic autoradiography and velocity sedimentation, RNA synthesis was examined in chick embryo cells infected with Japanese encephalitis virus (JEV). RNA was labelled with 3H-uridine for 5 min or 10 min at 15 h after infection in the presence of actinomycin D and D-glucosamine. Microautoradiography showed significantly numbers of silver grains on the nuclear membranes of 5 min pulse-labelled thin cell sections. The RNA species in membrane fractions obtained from the nucleus and cytoplasm of the infected cells were analysed by sucrose density gradient sedimentation. Radioactive 23S replicative form RNA and 8-12S RNA were obtained from the outer membrane fractions of the nuclear envelope. Labelled 42S virus RNA was obtained from the fractions containing large vesicle membranes and plasma membranes. These results suggest that JEV-RNA synthesis is initiated in the perinuclear region in close association with the outer membranes of the nuclear envelope.

Animals↗
PubMed1977

Intracellular distribution of virus-specific RNA in chick embryo cells infected with Japanese encephalitis virus.

Japanese encephalitis virus (JEV) infected chick embryo (CE) cells were treated with 4 mug actinomycin D/ml and 5 mM-D-glucosamine at 2 or 3 h before harvesting. Production of JEV was not affected by the short-time treatment of these drugs. The radioactivity in virus-specific RNA in the glucosamine-treated cells was a-parently higher than in non-treated cells. Nuclear and cytoplasmic extracts were prepared from the JEV-infected cells pulse-labelled with 3H-uridine at 15 h after infection. Analysis of virus RNA in nuclear extracts on sucrose density gradients showed that most of the radioactivity was in 23S RNA, 26S RNA and 8 to 12S RNA. The radioactivity of virus RNA in cytoplasmic extracts was found in 42S RNA and RNA fragments sedimenting at less than 8S.

Animals↗
PubMed1976

Inhibition of cellular DNA synthesis in hamster kidney cells infected with western equine encephalitis virus.

Infection of BHK cells with western equine encephalitis (WEE) virus resulted in rapid inhibition of cellular DNA synthesis. The rate of inhibition of DNA synthesis depended on the multiplicity of infection, and was closely related to virus replication. Cellular DNA synthesis was not inhibited in infected BHK cells that had been irradiated with ultraviolet radiation. These results indicated that a functional viral genome was required for the inhibition of DNA synthesis by WEE virus. The sharp decrease in thymidine incorporation into the acid-insoluble fraction was not due to a change in the intracellular pool of the acid-soluble fraction. Sedimentation analysis in alkaline sucrose gradients was used to show that cellular DNA was not degraded during WEE viirus infection. DNA polymerase activity in infected cells was not significantly reduced.

Cell Line↗
PubMed1975

Biohazards in the field of microbiology.

Eighty cases of laboratory infection observed in our institute during 25 years were summarized. They were mostly research workers. Cases include not only manifestation of disease but also incidence of allergic responses. Causal agents were viral 22, rickettsial 14, bacterial or fungi 33, and toxin 11. Air contamination was considered to be the main cause of the above biohazard. Therefore, most of those accidents must be avoided by careful installation of the laboratory. Special attention should be given in laboratories where field specimens are treated and experimental animals housed. It was pointed out that most of the autopsy halls in Japan are little equipped to protect biohazard.

Bacterial Infections↗