Sumsullah Khan

Generation of hydroxyl radicals during benzene toxicity

In the present study, an attempt has been made to detect formation of formaldehyde and degradation of deoxyribose as indicators of hydroxyl radical generation during benzene toxicity

Accumulation of low molecular weight (bleomycin detectable) iron in bone marrow cells of rats after benzene exposure

An accumulation of low molecular weight (LMW) bleomycin detectable iron in the bone marrow was observed after administration of benzene (IP 0.5 ml/kg, daily) for 5 and 10 days in female albino rats. However, this LMW iron was not detectable in the bone marrow of rats from the control group. Studies of bone marrow fractionation showed that the maximum accumulation of this LMW iron was in the mitochondrial fraction. An increase in the activity of superoxide dismutase and lipid peroxidation was also noticed in the benzene exposed groups.

Modulation of benzene toxicity by polyinosinic-polycytidilic acid, an interferon inducer

Repeated intraperitoneal administration of benzene (1.0 ml/kg body wt.) for 3 days produced leucopenia, lymphocytopenia and significantly decreased body wt. (P less than 0.001) and organ weights of thymus (P less than 0.001) and spleen (P less than 0.001) in female albino rats. Total iron content, lipid peroxidation and superoxide dismutase activity of the liver and bone marrow were significantly increased as a result of benzene exposure. Low molecular weight (LMW) bleomycin detectable iron content was accumulated in bone marrow, whereas hepatic LMW iron was not detectable after benzene intoxication to rats. Prior administration of single dose (250 micrograms/100 g body wt.) of Poly IC, an interferon inducer with immunomodulating potential was found to be ameliorate some of the adverse effects of benzene as well as restoration of hepatic architecture histologically. Superoxide dismutase activity, lipid peroxidation, total iron content and LMW iron content (bone marrow) were normalised. Pretreatment of animals with Poly IC was able to enhance the SRBC antibody titre in benzene-treated animals. This study suggests that the beneficial effects of Poly IC in the amelioration of the acute toxicity of benzene has clinical significance.

n-octane and n-nonane induced alterations in xenobiotic metabolising enzyme activities and lipid peroxidation of rat liver

After 2 and 7 days on n-octane and n-nonane administration (intraperitoneally) to female albino rats, alterations in the levels of hepatic xenobiotic metabolising enzyme activities and TBA reactants were observed. Fifty to eighty per cent reduction in the specific activities of benzo[a]pyrene hydroxylase, benzphetamine-N-demethylase, p-nitroanisole-O-demethylase and glutathione-S-transferase were observed. Cytochrome P-450 and free sulfhydryl contents of liver were also decreased significantly after 7 days treatment on n-octane and n-nonane. A 2- and 3- fold increase in liver lipid peroxidation estimated as TBA reactants was observed in the animals treated for 2 or 7 days with n-octane or n-nonane.

Distribution of Fe59 in benzene and iomex treated rats.

The distribution of Fe59 in plasma and blood at various time intervals has been studied in control, benzene and iomex administered, and anemic rats. A significant difference between control and benzene, and iomex treated animals was observed in the rate of reappearance of Fe59 in blood circulation. The accumulation of Fe59 in various organs was noted at the end of 48 h. A significant increase in the radio-iron content was observed in bone marrow, spleen and liver of benzene and iomex treated rats as compared to those of control rats.

Biochemical studies on the toxicity of n-octane and n-nonane.

Abstract n -Octane and n -nonane were administered to albino rats and biochemical studies were conducted after 2 and 7 days. Significant increase is observed in liver wet weight. Decreased activities of aniline hydroxylase, aminopyrine- N -demethylase, and glucose-6-phosphatase are noted in (9000 g ) supernatant of liver homogenate. A significant increase of phenobarbital-induced sleeping time is also noted.

Effect of adrenalectomy on diazinon-induced changes in carbohydrate metabolism

Treatment with diazinon resulted in hyperglycaemia and depletion of glycogen from cerebral and peripheral tissues 2 h after its administration in rats; the changes were maximal after 40 mg/kg diazinon, administered intraperitoneally. The activities of glycogen phosphorylase and phosphoglucomutase were significantly increased in brain and liver, while that of glucose-6-phosphatase was not altered. The activities of the glycolytic enzymes hexokinase and lactate dehydrogenase were increased only in brain. The cholinesterase activity of the brain was reduced by treatment with diazinon. The activities of hepatic gluconeogenic enzymes (fructose 1,6 diphosphatase and phosphoenolpyruvate carboxykinase) were also significantly increased in diazinon-treated animals. The level of lactate was increased in brain and blood while that of pyruvate was not changed. The activity of glucose-6-phosphate dehydrogenase was not significantly changed. Cholesterol and ascorbic acid contents of adrenals were depleted in diazinon-treated animals. Adrenalectomy abolished the hyperglycaemia and changes in carbohydrate metabolism, suggesting the possible involvement of adrenals in the induced changes in diazinon-treated animals.

Effect of n-octane and n-nonane administration on alkaline phosphatase activity in tissues of female rats

Studies on alkaline phosphatase were conducted in albino rats exposed to n-octane or n-nonane for 2 and 7 days; there was an increase in alkaline phosphatase activity of liver, spleen and bone marrow. Increase in spleen alkaline phosphatase activity persisted up to 42 days after single dose of n-octane or n-nonane. Pretreatment with protein synthesis inhibitors, cycloheximide or ethionine removed this observed increase of alkaline phosphatase activity in liver and spleen.