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Biomedical subjects

G Wilfred

Publications and source records attributed to G Wilfred.

At least 19 recordsLinked to original sources

Oxidative damage to the hepatocellular proteins after chronic ethanol intake in the rat.

BACKGROUND: Protein carbonyl content, a measure of oxidative damage to hepatocellular proteins, and the activities of some thiol-containing proteins were assayed in the liver and plasma, as thiol-containing protein, appear to be targets for free radicals. These may be important in the mechanism of ethanol-induced liver injury. METHODS: Tap water containing ethanol at the concentration of 25% (v/v) and phenobarbital (500 mg/l) was the only source of drinking water for the experimental rats for 24 months. Another group of rats were administered 25% (v/v) ethanol alone in drinking water for 24 months. Control rats were administered either phenobarbital alone in drinking water or tap water for 24 months. At the end of 24 months, the rats were sacrificed. The protein carbonyl content, activities of glutamine synthase and biotinidase-sulfhydryl group containing enzymes were assayed in the liver along with alkaline protease, an enzyme that degrades oxidized proteins. The total thiol, albumin and the activity of biotinidase were measured in the plasma. RESULTS: The protein carbonyl content of the liver was increased in the ethanol/phenobarbital-treated rats as well as in the ethanol-treated rats as compared with the controls. The activities of glutamine synthase and biotinidase were decreased significantly in the livers of ethanol/phenobarbital-treated rats as well as the ethanol-treated rats as compared with the controls. The activity of alkaline protease was increased significantly in both the ethanol-treated groups. In the plasma of ethanol/phenobarbital-treated rats as well as the ethanol-treated rats total thiol, albumin and the activity of biotinidase were decreased significantly as compared with the controls. The ethanol/phenobarbital-treated rats as well as the ethanol-treated rats developed fatty liver. CONCLUSIONS: Damage to proteins occurs upon chronic ethanol intake in the rat, and it may play a role in the pathogenesis of alcohol-induced fatty liver.

Animals↗

Decreased activity of hepatic alkaline protease in rats with carbon tetrachloride-induced liver cirrhosis.

To investigate the cause of accumulation of oxidised proteins in the livers of rats with carbon tetrachloride (CCl4) induced liver cirrhosis, the activity of alkaline protease (a high molecular weight, multisubunit cysteine proteinase) was determined in the cirrhotic livers. A significant decrease (P < 0.05) in the activity of hepatic alkaline protease was observed in the cirrhotic rats. Decreased activity of alkaline protease in the liver of cirrhotic rats may contribute to the accumulation of the oxidised proteins in the liver.

Animals↗

Does oxidative protein damage play a role in the pathogenesis of carbon tetrachloride-induced liver injury in the rat?

Free radicals have been implicated in the pathogenesis of alcohol-induced liver injury in humans and carbon tetrachloride (CCl4)-induced liver injury in rats. The most extensively studied aspect of free radical induced liver injury is lipid peroxidation. Recently it has been found that free radicals can cause oxidative damage to cellular proteins and alter cellular function. One such susceptible protein is the enzyme glutamine synthase (GS). The chemical effects of CCl4 on cell proteins and their biological consequences are not known. Hence, in our study, the effect of CCl4 on liver protein oxidation and GS activity were investigated and compared with lipid peroxidation. A significant increase in liver protein carbonyl content (2-3 fold) and a significant decrease in hepatic GS activity (44-57%) were observed. Damage to proteins was rapid in onset and increased with time. Acute exposure of rats to CCl4 resulted in an increase in hepatic protein carbonyl content and a decrease in hepatic GS within 1 h. In cirrhosis of the liver induced by CCl4, the decrease in hepatic GS activity was accompanied by a significant increase in plasma ammonia levels. We conclude that protein oxidation may play a role in the pathogenesis of CCl4 induced liver injury and that the accumulation of oxidised proteins may be an early indication of CCl4 induced liver damage.

Acute Disease↗

Urinary N-acetyl-beta-D-glucosaminidase in the prediction of preeclampsia and pregnancy-induced hypertension.

Urinary N-acetyl-beta-D-glucosaminidase was estimated in 109 primigravidas and the level correlated with the subsequent development of preeclampsia and pregnancy-induced hypertension in these women. The enzyme value was significantly higher in those who developed preeclampsia. Its sensitivity and specificity for the prediction of the disorder were 80% and 78% respectively. The positive predictive value was 21% while the negative predictive value was 98%.

Acetylglucosaminidase↗

Nystatin increases hepatic alkaline phosphatase activity.

The activity of alkaline phosphatase is increased significantly in the livers of rats after the intraperitoneal administration of nystatin. Studies with cycloheximide suggested that de novo protein synthesis was essential for the effect of nystatin on alkaline phosphatase activity. The induction of hepatic alkaline phosphatase by nystatin is not secondary to the release of glucocorticoids because the response of the enzyme to the administration of nystatin was not affected by bilateral adrenalectomy.

Adrenalectomy↗

Colchicine increases hepatic alkaline phosphatase activity.

In vivo administration of colchicine increases the activity of alkaline phosphatase significantly in the livers of rats. Prior treatment with cycloheximide prevented the induction of the enzyme by colchicine suggesting that de novo protein synthesis was essential for the effect of colchicine on alkaline phosphatase activity. Bilateral adrenalectomy did not affect the response of alkaline phosphatase following the administration of colchicine. This indicates that the rise in the level of alkaline phosphatase in liver caused by colchicine is not secondary to the release of glucocorticoids.

Adrenalectomy↗