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Biomedical subjects

K Yoshimoto

Publications and source records attributed to K Yoshimoto.

At least 235 records · Page 13Linked to original sources
PubMed1984

Central monoamines and the death process time (antemortem time) during asphyxia. An experimental study in the mouse brain.

The changes of the brain monoamines, norepinephrine (NE), dopamine (DA), and serotonin (5-HT), during acute asphyxia, caused by strangulation, anoxia, and drowning, were studied in the mouse. In several asphyxiated animal groups significant linear correlation was found between the level of monoamines, NE, DA, and 5-HT, and the death process times or antemortem times were r = 0.50, 0.98 (P less than 0.05), and 0.57, respectively. It is concluded that the level of brain NE and DA increased in the mouse that died of asphyxia, and the level of 5-HT showed only an apparent decrease in anoxia groups as compared with the control group and showed a twice as high increase in drowning groups. Especially, there was a tendency that the longer the death process times or antemortem times, the higher was the level of DA.

Animals↗
PubMed1983

Reciprocal effects of epidermal growth factor on key lipogenic enzymes in primary cultures of adult rat hepatocytes. Induction of glucose-6-phosphate dehydrogenase and suppression of malic enzyme and lipogenesis.

In primary cultured hepatocytes of adult rats epidermal growth factor (EGF) caused 2- to 3-fold induction of glucose-6-phosphate dehydrogenase (EC 1.1.1.49, G6P dehydrogenase) within 2 days. The effect of EGF was additive with a similar effect of insulin. The half-maximum dose of EGF for the induction was 1 ng/ml. Induction of this enzyme by these hormones was shown by immunotitration to be due to increase of the amount of enzyme. Furthermore, this increase in the amount of enzyme was found to result from increase of syntheses of mRNA and enzyme protein. In contrast, the induction of malic enzyme (EC 1.1.1.40, L-malate:NADP+) oxidoreductase) by insulin plus triiodothyronine was strongly suppressed by the concomitant addition of EGF. Induction of G6P dehydrogenase by EGF, like that by insulin, was not suppressed by either glucagon or dibutyryl cAMP, whereas that of malic enzyme was suppressed additively by EGF and dibutyryl cAMP. EGF also suppressed stimulation of lipogenesis by insulin, measured as incorporation of [1-14C]acetate into triglycerides and phospholipids. Another difference between the inductions of G6P dehydrogenase and malic enzyme was in their dependence on cell density; G6P dehydrogenase induction by insulin and EGF was high at low cell density (3 X 10(4) cells/cm2) and less at higher cell density (13 X 10(4) cells/cm2), whereas induction of malic enzyme was high at higher cell density and less at lower cell density. These results are consistent with the dual role of G6P dehydrogenase in lipogenesis in resting cells and in synthesis of nucleic acid in growing cells. Malic enzyme plays a role only for lipogenesis in mature hepatocytes.

Animals↗
PubMed1983

Hormonal regulation of translatable mRNA of glucose-6-phosphate dehydrogenase in primary cultures of adult rat hepatocytes.

The quantity of translatable mRNA of glucose-6-phosphate dehydrogenase (D-glucose-6-phosphate: NADP+ 1-oxidoreductase, EC 1.1.1.49) in primary cultures of adult rat hepatocytes subjected to different hormonal conditions was determined with a reticulocyte-lysate, cell-free system. The level of glucose-6-phosphate dehydrogenase mRNA was about 5-fold higher in the presence of insulin than in its absence. This increase of glucose-6-phosphate dehydrogenase mRNA reached a maximum 12 h after the addition of insulin. The maximum level of induction of glucose-6-phosphate dehydrogenase mRNA required 10(-8) M insulin. Glucagon and triiodothyronine had no effect on the glucose-6-phosphate dehydrogenase mRNA level. The increase of glucose-6-phosphate dehydrogenase activity correlated with the increase in level of mRNA of this enzyme. This suggests that the changes in glucose-6-phosphate dehydrogenase activity in response to the above hormonal changes are primarily due to changes in the amount of mRNA coding for this enzyme.

Animals↗
PubMed1983

Reciprocal modulation of growth and differentiated functions of mature rat hepatocytes in primary culture by cell--cell contact and cell membranes.

In primary monolayer cultures of rat mature hepatocytes, many metabolic functions as well as cell growth are regulated by cell density. There are two types of regulatory response of these functions to change of cell density. Growth-related functions, such as DNA synthesis, induction of glucose-6-phosphate dehydrogenase, 2-aminoisobutyric acid transport, synthesis of cellular protein, and cholesterogenesis, are stimulated by low cell density. In contrast, functions related to hepatocyte-specific characters, such as the inductions of tyrosine aminotransferase, serine dehydratase, and malic enzyme and synthesis of triglycerides, are stimulated by high cell density. The reciprocal responses of these cellular activities to cell density were mimicked by addition of plasma membranes purified from adult rat liver to hepatocytes cultured at low cell density. The modulator activity was heat labile and trypsin sensitive. The activity was also found in plasma membranes from kidney, brain, and erythrocytes, although the specific activities of these preparations seemed to be different. These results suggest that the reciprocal regulations of cell growth and hepatocyte-specific functions are mediated by some surface components via cell-cell contact.

Acetates↗
PubMed1983

A cohort study on the possible association between broiled fish intake and cancer.

To examine the possible carcinogenic effects of frequent intake of mutagenic pyrolysates of proteins and amino acids, 7,553 adult subjects whose personal characteristics had been examined were followed-up for about 11 years. The stepwise multiple regression analysis revealed that frequent consumption of broiled fish was significantly positively associated with mortality from cancer at all sites, as well as from cancer of the stomach. Among the 11 independent variables tested, consumption of broiled fish ranked high as a variable associated with cancer mortality (all sites, and stomach). Similar analyses done by sex and city (Hiroshima and Nagasaki) showed a consistently positive association of this variable with mortality from cancer at all sites, in both sexes and cities, but, with a few exceptions, the association was not statistically significant. Broiled fish consumption also showed a consistently positive but not statistically significant association with mortality from gastric cancer classified by sex and city. The relative risks of cancer mortality associated with frequent (twice or more weekly) consumption of broiled fish, as compared to less frequent consumption, were 1.3 (P less than 0.05) for cancer at all sites and 1.7 (P less than 0.05) for gastric cancer. The frequency of consumption of dried fish was hardly associated with deaths from cancer at all sites and from gastric cancer, but was significantly positively associated with deaths from cancer of the liver.

Adult↗
PubMed1983

[Factors affecting estrogen and progesterone receptors in primary breast cancer].

The contents of estrogen receptor (ER) and progesterone receptor (PgR) in 323 primary breast cancers were analysed with respects to the influence of a patients menopausal status, age, body weight, height, childbirth, abortion, size of tumor, node involvement and pathological diagnosis. Influence of menopausal status on the distribution of ER indicate that 68% of premenopausal women and 67% of postmenopausal women were ER positive, while only 44% paramenopausal women were ER positive. ER level was found to be higher in postmenopausal than in premenopausal women. In postmenopausal women, 87% of overweight (55kg and more over patients), 52% of non-overweight were ER positive. There was no significant correlation between ER or PgR rate and height, childbirth, abortion, size of tumor, axillary node involvement, pathological diagnosis.

Adult↗
PubMed1982

Hormonal regulations of glucose-6-phosphate dehydrogenase and lipogenesis in primary cultures of rat hepatocytes.

In primary cultured monolayer hepatocytes of adult rats, insulin (1 x 10(-8) M) induced glucose-6-phosphate dehydrogenase [EC 1.1.1.49, G6PDH] several fold in 48 h. It also induced lipogenesis, measured as [1-14C]acetate incorporation in 2 h, in these cells. Of the various lipids, triglycerides and phospholipids were induced markedly, while cholesterol and its esters were not induced. The increase of G6PDH and lipogenesis were parallel. Glucagon, dibutyryl cyclic AMP, triiodothyronine, dexamethasone, epinephrine, isoproterenol, and dibutyryl cyclic GMP were also tested under similar conditions, but none of them caused significant induction of G6PDH or lipogenesis. Use of anti-G6PDH serum showed that induction of G6PDH by insulin was due to increase in the amount of enzyme protein. Insulin was found to increase the rate of synthesis of G6PDH about 3-fold. SDS-polyacrylamide gel electrophoresis of the immunoprecipitable protein revealed that besides G6PDH another radioactive fraction (Mr 37,000) was increased by insulin. This suggests that complete synthesis of G6PDH protein is slowed down in primary cultured hepatocytes and that an apparent nascent peptide of the enzyme accumulates. Although on long-term treatment (48 h), glucagon and dibutyryl cyclic AMP had no effect on lipogenesis, when added with [14C]acetate for 2 h they strongly inhibited lipogenesis. Significant inhibition of lipogenesis by short-term treatment with glucagon was seen even in cells with a high capacity for lipogenesis induced by long-term treatment with insulin. Insulin again stimulated lipogenesis in short-term treatment, but its effect was slight. It is concluded from these results that insulin exerts long-term stimulation of lipogenesis by inducing enzymes related to lipogenesis including G6PDH as well as causing slight stimulation by enhancing supply of substrate for lipogenesis. Glucagon seems to play a minor role in long-term control, but it causes short-term inhibition of lipogenesis.

Animals↗
PubMed1982

Primary liver carcinoma and liver cirrhosis in atomic bomb survivors, Hiroshima and Nagasaki, 1961-75, with special reference to hepatitis B surface antigen.

During 1961-75, 128 cases of primary liver carcinoma (PLC) in the Radiation Effects Research Foundation life-span study extended sample and 301 cases of liver cirrhosis in the pathology study sample were observed. The presence of hepatitis B surface antigen (HBsAg) was assessed in all of the cases with the use of orcein and aldehyde fuchsin stains and was confirmed by the immunofluorescence technique. The incidence of PLC was two times higher in Nagasaki than in Hiroshima, which was statistically significant, but little difference was noted in the prevalence of cirrhosis in the two cities. Findings that might possibly explain the higher PLC incidence in Nagasaki were 1) the 2.3 times higher presence in Nagasaki than in Hiroshima of HBsAg in the livers of subjects without liver disease and 2) the two times higher prevalence in Nagasaki than in Hiroshima of cirrhosis with PLC. We believe that the higher incidence of PLC in Nagasaki is attributable to hepatitis B virus infection, although other factors (e.g., immunologic competence affected by radiation) cannot be excluded. In both cities, a suggestive relationship of radiation dose to cirrhosis prevalence, but not to PCL prevalence, was noted. To clarify possible radiation effects on cirrhosis prevalence, further follow-up of the populations of these two cities is necessary.

Adult↗
PubMed1982

Radiation exposure and thyroid cancer incidence among Hiroshima and Nagasaki residents.

The dependence of thyroid cancer incidence on radiation exposure level is examined with the use of tumor registry follow-up data on a life-span cohort of 98,610 Hiroshima and Nagasaki residents. The sample includes 112 clinically evident thyroid cancer cases: 62 in Hiroshima and 50 in Nagasaki. A clear, predominantly linear, increase in thyroid cancer incidence corresponds to increasing levels of gamma radiation to the thyroid gland, whereas neutron exposure could not be shown to contribute further to thyroid cancer risk. The relative risk associated with gamma ray exposure is particularly high among persons who were less than 30 years old at the time of radiation exposure. Limitations on the incidence and dosimetry data are discussed, as well as the ability of the Cox regression method to accommodate some of these limitations.

Aged↗