Biomedical subjects

A Oshima

Publications and source records attributed to A Oshima.

At least 181 records · Page 10Linked to original sources

PubMed1982

Regulation of the phosphatidylethanolamine methylation pathway in Saccharomyces cerevisiae.

1. Phosphatidyl-N-methylethanolamine methyltransferase mutants of Saccharomyces cerevisiae were isolated. Genetic analysis showed that phosphatidylethanolamine methyltransferase and phosphatidyl-N-methylethanolamine methyltransferase are coded for by separate genes. Phosphatidyl-N-methylethanolamine methyltransferase activity and phosphatidyl-N,N-dimethylethanolamine methyltransferase activity appeared to be catalyzed by the same enzyme. 2. Phosphatidyl-N-methylethanolamine methyltransferase was found to be repressed by myo-inositol and choline. Both myo-inositol and choline at concentrations of 10 micrograms/ml were required for repression. The decreased enzyme level was restored by the removal of myo-inositol or choline or both. 3. Both myo-inositol and choline were required for the maximum repression of phosphatidylethanolamine methyltransferase in wild-type cells. In contrast, choline was not required for the repression of the enzyme in mutant strain 172. This was due to a single nuclear gene mutation in the genome of strain 172. 4. The activity of the phosphatidylethanolamine methylation pathway in cells decreased with time on incubation of cells with myo-inositol and choline, myo-Inositol could not be replaced by other structurally related compounds, such as scyllo-inositol or mannitol. 5. The physiological significance of the repression of the phosphatidylethanolamine methylation pathway is discussed with respect to the mechanism for maintaining the contents of phosphatidylethanolamine and phosphatidylcholine at normal levels.

Choline↗

PubMed1982

Multiple primary cancers following exposure to benzidine and beta-naphthylamine.

The incidence of second primary cancers has been ascertained in 3,322 employees who had worked from 1950 to 1978 in industries in Japan that manufactured benzidine and beta-naphthylamine. Of the 244 workers who had suffered from and died of cancer of the genitourinary organs (first primary cancer), 11 (all male) had subsequent primary, histologically confirmed cancers of the liver, gallbladder, bile duct, large intestine, and lung. A control group of 177 male bladder cancer patients, assembled from the Osaka Cancer Registry during 1965-1975, showed eight cases of a second primary, five being stomach cancer. No stomach cancer was observed in the study cohort. A statistically significant excess risk for liver, gall bladder, and bile duct cancer (p less than 0.05) was found The number of observed deaths from respiratory cancer was greater than expected, though not statistically significant. These findings appear to confirm previous clinical data suggesting an increased occurrence of multiple primary cancers in workers exposed to benzidine/beta-naphthylamine, pointing to a pluripotential action of these carcinogens.

2-Naphthylamine↗

PubMed1982

Cancer mortality among Koreans in Osaka, Japan.

Using data from the Osaka Cancer Registry, we calculated age-standardized cancer mortality rates among Koreans and Japanese living in Osaka, Japan, during 1968-77. The following points were elucidated: 1) Among Koreans in Osaka, the mortality rate for liver cancer was about twice that among Japanese; 2) Among Koreans in Japan, the mortality rate of stomach cancer has been declining more rapidly than it has among Japanese. The factors involved in the Korean-Japanese difference of liver cancer and those involved in the rapid decrease of stomach cancer among Koreans in Japan are discussed.

Adult↗

PubMed1980

Regulation of phosphatidylethanolamine methyltransferase level by myo-inositol in Saccaromyces cerevisiae.

1. A conditional choline auxotroph was isolated. The growth of this mutant was markedly inhibited by the addition of a low concentration of myo-inositol to the culture medium. The growth inhibition was completely prevented by the addition of choline. 2. When this mutant cell was grown in the presence of myo-inositol, the intracellular level of phosphatidylethanolamine methyltransferase was very low, whereas in the cell grown in the absence of myo-inositol the enzyme level was normal. The addition of myo-inositol to the cell grown in the absence of myo-inositol caused a marked decrease in the methyltransferase level. 3. The reduction in phosphatidylethanolamine methyltransferase level by myo-inositol also occurred in various wild type strains of Saccharomyces cerevisiae. 4. The decreased methyltransferase activity was restored by the removal of myo-inositol from the culture medium. The restoration of the enzyme level was completely abolished by cycloheximide. Thus, it was shown that protein synthesis was involved in the change of phosphatidylethanolamine methyltransferase level by myo-inositol. 5. These results suggest that the synthesis of phosphatidylcholine from phosphatidylethanolamine by the methylation pathway is regulated by myo-inositol.

Inositol↗

PubMed1979

A method of record linkage.

In cancer epidemiology, prospective approaches are very important both in testing etiological hypotheses and in evaluating preventive procedures. Prospective studies, however, are very difficult and expensive, because a large number of people and a long period of observation are necessary for a satisfactory study. As a data source for follow-up studies, population-based cancer registry is very useful. The Osaka Cancer Registry has been in operation since December, 1962. Since 1968 the data processing, including the work of collation, has been semicomputerized. In order to identify cancer patients, we use the following six indices: date of birth, first Chinese character of a person's family name, address a: city, ward, town or village, address b: further details. i.e., street, avenue, section, hamlet etc., site, and sex. When we have data on the collation indices for the subjects to be followed up, we can conduct follow-up studies easily and accurately, using a semicomputerized collation method similar to that in the cancer registration system. Because the master file of the Osaka Cancer Registry contains the data of cancer cases reported and all cancer deaths among the residents of Osaka Prefecture, we can follow up the subjects living in Osaka Prefecture and obtain data about vitually all cancer incidences and deaths among them. In this follow-up method by means of record linkage to the cancer registry, some considerations should be taken into account for the following factors; coverage of cancer data in the Osaka Cancer Registry, reliability of the collation method, and address of the subjects to be followed up. As an example of a study with this method, we present the follow-up study of the screenees of a mass screening program for stomach cancer.

Computers↗

PubMed1979

Evaluation of a mass screening program for stomach cancer.

To evaluate a mass screening program for stomach cancer, we followed 32,789 subjects for 6.1 years by means of a record linkage to a population-based cancer registry. The results show that the mortality from stomach cancer among those studied decreased by 9% as compared with the expected number calculated on the basis of the sex- and age-specific rates among the general population. When the study subjects were limited to those aged 40-59 years, the decrease in stomach cancer deaths became more marked, i.e., a 26% decrease was observed. Because this study is not a controlled trial, the results must be interpreted with the reservation that some biases were present in the study subjects.

Adult↗

PubMed1979

Descriptive epidemiology of cancer in Japan: current cancer incidence and survival data.

The Research Group for Population-Based Cancer Registration in Japan, which has been collecting cancer incidence and mortality data from participating registries annually since 1974, has also been estimating cancer incidence rates for the whole of Japan by sex, age, and site. Data from the third survey have now been analyzed. Marked changes have been observed by the Osaka Cancer Registry in incidence rates of some sites during this period. Five-year relative survival rates for registered cancer cases have been calculated by the Osaka Registry for the first time in Japan.

Adolescent↗

PubMed1976