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Biomedical subjects

H Tsuda

Publications and source records attributed to H Tsuda.

At least 685 records · Page 38Linked to original sources
PubMed1976

Carcinogenic activity of quinoline on rat liver.

The effects of prolonged p.o. administration of quinoline or 2-chloroquinoline on rat liver were examined histologically. Hepatocellular carcinomas and hemangioendotheliomas were observed in the livers of rats fed a basal diet containing 0.05, 0.10, or 0.25% quinoline for about 16 to 40 weeks. However, no neoplastic changes were seen in the livers of rats fed a basal diet containing 0.05, 0.10, or 0.25% 2-chloroquinoline for 40 weeks. In groups that received low concentrations of quinoline, the incidences of hepatocellular carcinomas were higher and the incidences of hemangioendotheliomas were lower than in the group that received a high concentretion of quinoline. The liver tumors induced by quinoline were classified histologically as hemangioendotheliomas or hemangiosarcomas and trabecular hepatocellular carcinomas. Typical nodular hyperplasias were occasionally seen in the livers of rats treated with quinoline. 2-Chloroquinoline did not induce any nodular hyperplasia or other neoplastic changes, but it caused diffuse fatty changes of parenchymal cells. Oval cell infiltration and bile duct proliferation were slight or moderate. Cirrhotic changes were rare in the livers of rats treated with either quinoline or 2-chloroquinoline. The serum levels of glutamic oxaloacetic transaminase and alkaline phosphatase were slightly changed in groups treated with quinoline, but no other remarkable changes were detected.

Alkaline Phosphatase↗
PubMed1976

Reversibility and irreversibility of liver tumors in mice induced by the alpha isomer of 1,2,3,4,5,6-hexachlorocyclohexane.

The characteristics of liver tumors in mice induced by the alpha isomer of 1,2,3,4,5,6-hexachlorocyclohexane (alpha-BHC), were studied with emphasis on their reversibility of irreversibility. Male 8-week-old DDY mice were fed basal diet supplemented with 500 ppm of alpha-BHC for 16, 20, 24, and 36 weeks and then were fed basal diet without alpha-BHC for 4, 8, 12, 16, 24, or 36 weeks. At various intervals, 13 to 20 mice were killed for light and electron microscopic observations. The incidences of liver tumors in mice induced by alpha-BHC increased progressively on continuous administration of alpha-BHC, but when its administration was discontinued some tumors disappeared. Histologically, after alpha-BHC administration for 24 weeks, most tumors were nodular hyperplasias, and there were only a few well-differentiated hepatocellular carcinomas. However, 60 or 72 weeks after the beginning of the experiment, most of the liver tumors were hepatocellular carcinomas and there were only a few nodular hyperplasias. At a later stage, 60 or 72 weeks, the liver parenchymal tissue in nontumorous areas was essentially normal, but small foci were occasionally seen in nontumorous areas that were composed of remaining hyperplastic nodular cells, phagocytic cells, Kupffer cells, and leukocytes. These findings suggest that the reversible tumors were usually nodular hyperplasias whereas the irreversible tumors were hepatocellular carcinomas. After alpha-BHC administration was stopped, many mesenchymal cells infiltrated the nodular hyperplastic lesions, and degenerated liver cells were found. These observations indicate that mesenchymal cell elements may be important in reversing the growth of liver tumors induced by alpha-BHC.

Animals↗
PubMed1976

In vitro transformation of newborn hamster cells induced by sodium nitrite.

The in vitro carcinogenicity of sodium nitrite was examined. Addition of a high concentration of sodium nitrite (50 mM or 100 mM) to mass cultures of newborn hamster cells for 24 hr resulted in morphological transformation of the cells. The shortest time required for morphological transformation after this treatment was 21 days. Two of 5 transformed cultures produced progressively growing tumors when injected into young adult hamsters. These tumors were diagnosed as fibrosarcomas. In two control cultures of the same experimental groups, transformed cells appeared 10 weeks or more later than those in treated cultures. The chromosomes were analysed at several stages of transformation. In the early stages of transformation, chromosome number varied widely from near diploid to tetraploid, but later they became near diploid. Morphological alteration caused by sodium nitrite was also seen in a short-term assay, in which hamster embryonic cells (1 x 10(4) cells/60 mm dish) were treated and morphology was observed 8 days after the treatment.

Animals↗
PubMed1975

Precocious differentiation of immature chief cells in fundic mucosa of infant rats induced by hydrocortisone.

Injection of hydrocortisone into developing rats induced precocious increase in the potential peptic activity of pepsinogen in the fundic mucosa, change from the immature to the mature electrophoretic pattern of pepsinogen isozymes and morphological change from the immature to the mature chief cells. The continual presence of hydrocortisone was required for maintenance of mature chief cells.

Animals↗