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Biomedical subjects

H Tauchi

Publications and source records attributed to H Tauchi.

At least 91 records · Page 5Linked to original sources
PubMed1975

The formation of enlarged and giant mitochondria in the aging process of human hepatic cells.

Measurement of area, circumference and total length of membrane profile of mitochondria of hepatic cells in 61 human biopsy materials (age range 21 to 81 years) have been ultramicrometrically performed on electron micrographs, supplemented by electroncytochemical examination of cytochrome c oxidase activity in some cases. The mitochondria decreased in number after 60 years of age. The first stage of compensation for the numerical loss of mitochondria was achieved by an increase of cristae in each mitochondrion, followed with a five year lag by an increase in their size. Formation of enlarged and giant mitochondria in aging process following the significant decrease in their number, may be considered to be of similar mechanism to polyploidization of the nucleus, whose division is interfered.

Adult↗
PubMedDate not supplied

Effect of environmental conditions upon age changes in the human liver.

Age changes in the liver of the Hawaii-Japanese have been compared with those of native Japanese and Caucasians in the United States. Among the Japanese in Hawaii, all cases over 70 years of age were migrant Japanese to Hawaii, i.e. Issei, those under 60 years of age were their Hawaii born descendents, i.e. Nisei, and cases in the 7th decade were composed of Nisei and Issei. Aging changes of the liver seem to begin earlier in the Nisei and Caucasians than in the native Japanese. The earlier onset of aging can be explained on the basis of earlier maturation due to better nutritional conditions. The marked decrease in the number of hepatic cells in the Issei may well be a reflection of their nutritional state during their early years. They, in this sense, resemble the native Japanese.

Adult↗
PubMedDate not supplied

Change of the hepatic cells in parabiosis between old and young rats.

The hepatic cells of the parabiotic unions 3 to 9 months after uniting between old and young rats were micrometrically examined. In the older parabiotic partners, it cannot be denied that the character of the findings tended in part towards that of the young controls. In the younger parabiotic partners, the estimated number of hepatic cells was apparently decreased, size of the hepatic cells and their nuclei was significantly increased, and number of binucleate hepatic cells was markedly increased. The findings of the hepatic cells in the younger partners were similar to those in the old controls. From the results, it is inferred that the proliferation of the hepatic cells of the younger parabiotic partners is inhibited by the inhibitory factors for cell division secreted from the hepatic cells of the older partners.

Aging↗
PubMedDate not supplied

Morphometric studies on the age changes of autofluorescent granules and lysosomes in the epithelial cells of rat kidneys.

Morphometric analysis of the lysosomal system in the proximal convoluted tubules of the kidney of rats of different ages was studied, with special regard to the accumulation of autofluorescent pigment in the epithelial cells. After maturity, the lysosomal amount in the epithelial cells was significantly increased in the 25-29-month-old group; however, the amount of autofluorescent pigment granules was not significantly increased.

Aging↗
PubMedDate not supplied

Morphological aspects of aging liver: half a century of progress in Japan.

The most important morphological aspects of the physiological changes of the liver with age are decreases in the numbers of hepatocytes and their mitochondria, coupled with increases in their volumes. The latter is considered to partially compensate for the decrease in numbers of hepatocytes and mitochondria, but leads to a more limited reserve capacity and thus to a condition in which liver function can be more readily exhausted. The binuclearity and polyploidization of the hepatocytes increase with age and are considered to be due to inhibition of their cell division process. Our studies on the parabiosis between young and old rats and mice, on the implantation of isolated hepatocytes in the spleens of rats of different ages, and on the regenerative process after partial hepatectomy in rats of different ages, suggested the existence of humoral inhibitory factor(s) for the division of the cells and their mitochondria. Morphological studies on the native and Hawaiian Japanese, as well as on the USA Caucasians and the Costa Rican Latinos revealed that a difference in the process of the age-related decrease in hepatocyte number among different ethnicities is mainly due to differences in nutritional conditions rather than to genetic factors. Experimental studies are now being carried out on the effect(s) of various dietary conditions on age-related changes of the liver, and the results obtained support the findings of the geographical studies.

Journal Article↗