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Biomedical subjects

T Okuno

Publications and source records attributed to T Okuno.

At least 451 records · Page 25Linked to original sources

Red cell size as measured by the Coulter model S.

The MCV (mean corpuscular volume) was examined by the Coulter model S. It was found that the MCV measured by the Coulter S was larger than the generally accepted range 82 to 92, or 76 to 96 mu(3). The range in 500 healthy individuals was 82.2 to 100.6 mu(3). It was also found that the mean MCV became larger with increasing age. No sex difference was found. The low MCV by manual methods was generally thought to be attributed to less accurate measurement of erythrocyte counts.

Adolescent↗

The effect of vaccination with a live attenuated strain of Japanese encephalitis virus on stillbirths in swine in Taiwan.

Since an excellent candidate strain (M) for live virus vaccination of swine against Japanese encephalitis was developed, a number of large vaccination programmes have been implemented in Japan with the aim of controlling Japanese encephalitis epidemics in man by reducing the population size of nonimmune swine. Encouraging results have been obtained but no studies have been made on the benefits of live-virus vaccination to the industry. In order to determine the effect of vaccination upon the number of stillbirths occurring in the Japanese encephalitis post-emergence season, a total of 74 vaccinated, and subsequently mated, gilts at a large breeding farm in subtropical Taiwan were subjected to follow-up observations in comparison with a control group. The total incidence of litter stillbirths in the vaccinated group (1/74) was significantly lower than that in the control group (21/68). Over 92% of the newborn piglets from the vaccinated gilts were healthy, while 31.6-54.1% of the newborn piglets in the control groups were stillborn. The litter size of vaccinated gilts was larger than that of the control gilts. The vaccine was shown by tests in 22 swine to have an adequate degree of safety. Four weeks after vaccination with either 10(5.6) or 10(8.0) smicLD(50) of virus, all the swine developed an adequate level of antibody. The results indicate that live virus vaccination could benefit the industry in addition to achieving the main aim of controlling Japanese encephalitis viraemia in swine.

Animals↗

Rates of infection with Japanese encephalitis virus of two culicine species of mosquito in Taiwan.

The role of Culex annulus as a Japanese-encephalitis (JE) vector has been drawing increasing attention recently. In this small trial, the rate of JE virus infection in C. annulus was compared with that in C. tritaeniorhynchus summorosus in the north-western coastal area of Taiwan, where both species are common as JE vectors. In order to increase the recovery rate of the virus, the mosquitos were artificially incubated at 26-28 degrees C for 10 days after collection. Two out of 6 C. t. summorosus pools and 7 out of 31 C. annulus pools, collected during a 17-day period in June 1969, were positive for JE virus. The results strongly suggest that one of the factors determining the severity of virus emergence in Taiwan is the total density of both species during the critical period of emergence of viraemic amplifiers: the relative prevalence of the two species of mosquito seems to be less important.

Animals↗

Immunotyping of different strains of Japanese encephalitis virus by antibody-absorption, haemagglutination-inhibition and complement-fixation tests.

The immunological characteristics of 26 strains of Japanese encephalitis virus (JEV) isolated in Japan and Malaya between 1935 and 1966 have been investigated mainly by the antibody-absorption variant of the haemagglutination-inhibition test, and to a certain extent also by conventional haemagglutination-inhibition and complement-fixation tests. The antibody-absorption technique shows promise as a routine method for the immunotyping of JEV.At present, two immunotypes can be distinguished. One comprises 2 strains, Nakayama-NIH and I-58, and is designated as the I-58 immunotype. The other immunotype, JaGAr 01, comprises 17 strains which share the characteristics of the JaGAr 01 strain, including one subline of the Nakayama strain, Nakayama-Yakken. The Nakayama-RFVL strain was found to have the characteristics of both immunotypes. The I-58 immunotype differs more markedly from related arboviruses, such as the Murray Valley encephalitis virus and the West Nile Eg101 strain, than does the JaGAr 01 immunotype.Evidence is presented which suggests that a given JEV strain can change immunotype on repeated passage through mice.

Animals↗