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K Simizu

Publications and source records attributed to K Simizu.

28 records · Page 2Linked to original sources
PubMed1988

Lindane-induced oxidative stress. II. Time course of changes in hepatic glutathione status.

1. Four hours after treatment of rats with lindane (60 mg/kg), hepatic GSH content was decreased (22%) and GSSG was increased (20%), while biliary concentration and excretion of both GSH and GSSG and bile flow were diminished. These changes coincide with the onset of hepatic lipid peroxidation. 2. The changes induced by lindane at 4 h disappeared at 6 h after treatment, but liver GSSG content (91%), biliary GSSG excretion (133%) and bile flow (42%) were enhanced at 24 h. 3. The data indicate that lindane treatment elicits marked changes in hepatocyte glutathione status, with a decrease in the GSH/GSSG ratio at early (2-4 h) and late (24 h) periods of poisoning.

Animals↗
PubMed1986

Dose-dependent study of the effects of acute lindane administration on rat liver superoxide anion production, antioxidant enzyme activities and lipid peroxidation.

The administration of single i.p. doses of lindane (20, 40, 60 and 80 mg/kg) to rats produced a progressive increase in the liver microsomal content of cytochrome P-450 and in the rate of superoxide anion generation, as measured by adrenochrome formation. A dose-dependent increase in lipid peroxidation of liver homogenates, assessed by measuring thiobarbituric acid reactants, was also found. Lindane treatment did not alter the activity of liver glucose-6-phosphate dehydrogenase, glutathione reductase or glutathione peroxidase, while that of superoxide dismutase and catalase was significantly reduced. These changes were accompanied by a progressive liver steatosis. The collected metabolic data were interpreted in terms of a causal relationship between an increase in superoxide radical generation, secondary to cytochrome P-450 induction and a resulting increase in lipid peroxidation. The decrease in superoxide dismutase and catalase activities is likely to contribute to the increased levels of lipid peroxidation in view of their antioxidant properties.

Animals↗
PubMed1985

[Novel transforming genes detected in human stomach cancer cells].

The DNAs of six human stomach cancer cell lines were analysed, and specific gene amplification was observed; namely, an 8-fold amplified c-Ki-ras-2 gene (1 case) and a 20-fold amplified c-myc gene (1 case). In addition, it was found that a single 11-kbp-Eco-R1 fragment, having weak homology to the Ki-ras gene, was amplified 5-10 fold in three out of the six cell lines. The DNAs of two of these three cell lines gave rise to foci upon transfection into NIH3T3 cells and the primary and secondary transformants seemed to carry a similar 11-kbp-Eco-R1 fragment. It was also found that one of the DNAs from human stomach cancers gave rise to NIH3T3 cell foci upon DNA transfection. DNAs of secondary transformants commonly retained six Eco-R1 fragments that contained human Alu repeats. The size of this gene was estimated to be about 50 kbp. The Southern blot hybridization profile of this gene revealed it to be clearly different from known active human oncogenes. Furthermore, about 70% of this gene has been isolated and portions of it used as probes to test for homologies to known viral oncogenes. The gene appears to be unrelated to 14 viral oncogenes so far tested.

Cell Line↗
PubMed1975

The effect of beta-bromopyruvic acid on fructose-1, 6-diphosphate aldolase from rabbit muscle.

Rabbit muscle aldolase (RMA) is 96 per cent inhibited in the presence of beta-bromopyruvic acid (BPA) in a molar ratio of 1/250, during 60 minutes incubation. The chemical reaction of higher significance in this phenomenon is the alkylation of -SHgroups of both apparent and buried types, with formation of S-pyruvil-cystein. The previous treatment of the enzyme with FDP protects aldolase, decreasing the rate of inhinition by BPA to about 56 per cent. FDP protection of the enzyme protects nearly 5-SH groups against the alkylating effect of BPA. Cyanogen bromide hydrolysis of the carboxymethylated protein results in the classical formation of 4 fragments, peptides F1, the NH-2terminal; F2, the COOH-terminal; F3, the active site containing peptide; and F4, a small peptide located between F2 F3. The protection bestowed upon the enzyme by FDP, against the alkylating effect of BPA, is located in the F1, F2, and F3 either in BPA treated aldolases or in the BPA treated FDP-aldolase. Part of the inhibiting effect of BPA is then attributed to the possible interaction between this compound and the basic aminoacids in the aldolase molecule.

Animals↗