R.N. Khanna

The acute toxicity of endosulfan to fresh-water organisms

A static bioassay is performed for measuring the short-term (96 h) toxicity of endosulfan to juvenile catfish Clarias batrachus, insect nymph Enallagma sp. and frog tadpoles of Rana tigrina. Median Tolerance Limit, Slope Function, Confidence Limit, and Presumable Harmless Concentration were computed. The results showed that frog tadpoles are more susceptible to endosulfan than insect nymph and catfish. Morphological changes and behavioural alterations were evaluated as symptoms of endosulfan toxicity.

Effects of the level of dietary protein on the toxicity of hexachlorocyclohexane in rats

Male albino rats were fed for 28 days from weaning on diets containing 5% (group 1), 10% (group 2) and 21% (group 3, normal protein) protein as casein. At the end of dietary period, HCH was administered daily for 30 days to investigate the interaction between protein deficiency and pesticide toxicity. The results indicated that rats fed a lower protein diet and HCH had a higher mortality, lower rate of growth, increased liver weight and deposition of the pesticide in blood and tissues in larger amounts. Blood pressure (systolic and diastolic) was significantly increased and the heart rate showed tachycardia in low protein exposed animals. A significant increase of total lipids, cholesterol, triglycirides, free fatty acids in serum and tissues of animals exposed to low protein was observed. A close correlation existed between lipid accumulation and storage of HCH in tissues and dietary protein seemed to play an important role in detoxification.

Lindane-induced changes in glucose and glutathione levels in cats

Cats were given lindane (1 and 2 mg/kg i.v.) and the levels of glucose in blood and glutathione in blood and liver were measured at 30 min, 1, 2, 4 and 8 h. The results showed a sharp decrease in blood glutathione at an early interval with subsequent recovery, whereas there was no change in liver up to 2 h followed by a significant decrease at later intervals with no sign of recovery. The pesticide also showed a hypoglycemic effect at all intervals.

Some Neurotoxicological consequences of Hexachlorocyclohexane (HCH) stress in rats fed on protein deficient diet

Hexachlorocyclohexane (HCH), an organochlorinated pesticide used extensively for the protection of crops, has been reported to affect the central nervous system. Attempts have been made to validate the behavioural changes including distance travelled, time resting, stereotypic time, ambulatory time, stereotypic movements and vertical movements in rats treated with HCH (50 mg/kg) and fed on protein deficient diet (5% Casein) for 120 days. Significant (P < 0.001) increase of 5‐HT uptake by platelets was recorded in pesticide exposed animals. Similarly ADP induced aggregatory responses were found to be enhanced significantly (P < 0.001). Bioaccumulation of pesticide in vital organs suggest that insecticide circulate rapidly through the body and can have a rapid and definitive effect. Changes in behaviour and platelets function may also be claimed to the promising sign of neurotoxicity occurring at the lower level of pesticide exposure under the influence of malnutrition.

Changes in cardiac rhythm and calcium levels in guinea pigs treated chronically with fenitrothion

Fenitrothion, an acetylcholinesterase inhibitor, causes bradycardia following long‐term exposure. To analyse the mechanism underlying these cardiac changes, ginea pigs were exposed to fenitrothion 5 and 10 mg/kg for 30 consecutive days. Electrocardiogram (ECG) showed increase in PR and RR intervals. These changes were more prominent in the animals receiving 10 mg/kg fenitrothion which occasionally showed extrasystoles. In isolated atria preparation heart rate was decreased at higher dose. Amplitude of cardiac rhythm decreased with respect to increased ACh concentration. Hypocalcemia was recorded in fenitrothion‐treated animals. The residual content of fenitrothion was increased in both groups of animals following a pattern: brain> spleen> heart> liver> kidney.

Distribution of lindane in plasma and brain after a single administration to cats

The distribution of lindane and its metabolites in the plasma and brain of the cats after 30 minutes, 1, 2, 4 and 8 hours of administration of lindane (2mg/kg, i.v.) was investigated. The compound distributes differentially in the CNS and this pattern changes with time. The pattern of distribution shows that although lindane concentration is higher in areas with a high myelin content, it disappears more rapidly from gray matter. The plasma levels were also high at 30 minutes interval and then gradually decreased. The rate of formation of the metabolite 2,4,6‐Trichlorophenol appeared to be maximum in the first 4 hours. The accumulation of the compound and its metabolite in brain during the experimental period was not evident.

Influence of dietary protein deficiency on EEG neurotransmitters and neurobehaviour after chronic exposure to HCH

The problems of pesticide toxicity is of great importance where malnutrition is a rampant health problem. Rats fed on synthetic diet (21% & 5% Casein) were given orally 50 mg/Kg Hexachlorocyclohexane (HCH) for three months period. Neurotransmitters measured from the discrete areas of brain showed significant increase of dopamine (DA) and decrease in the levels of 5‐Hydroxytryptamine (5‐HT) and norepinephrine (NE). Acetylcholine (Ach) content in cerebral cortex was increased. Behavioural observations included distance travelled, resting time, ambulatory and Stereotypie movement showed marked changes on optovarimax, while a significant increase (p < 0.001) was noticed in vertical movement of the rats exposed to HCH. Electroencephalograph records showed bursts of spikes with increased wave frequency.

Effect of repeated exposure to lindane and cadmium on lindane metabolism in rats

The effects of daily administration of cadmium and lindane for 35 days on the metabolism of lindane in rats were investigated. The results indicate that cadmium induces a significant inhibition of lindane metabolism, since the group dosed with lindane plus cadmium had a significantly higher concentration of lindane in plasma and tissues than the group dosed with lindane alone. The inhibition in the metabolic rate of lindane is associated with the cadmium-induced alterations in the disposition of essential trace elements, Zn, Cu and Fe, in the liver.

Effect of hexachlorocyclohexane on biochemical parameters of rats on a protein deficient diet

Male albino weanling rats were fed diets containing 5% (group I) and 21% (group II) protein as casein for 28 days. At the end of the dietary period Hexachlorocyclohexane (HCH) was administered daily for 30 days to investigate the effect of protein deficiency on the toxicity of HCH. The results indicated that rats fed a low protein diet and HCH had a higher mortality, lower rate of growth and increased liver weight. An increased glycogen and decreased glutathione level was also observed in their livers. A significant decrease in blood glucose, erythrocyte enzyme G6PD and LDH of animals exposed to low protein diet is suggestive of the disruption of the energy provision of the cell.

Effects of hexachlorocyclohexane administration on distribution of trace metals in rat tissues

The effects of daily administration of hexachlorocyclohexane (HCH) for 90 days on the distribution of Cu, Zn, Fe and Mn in rat tissues were investigated. The results indicated that HCH caused a significant increase in weight of liver and spleen and decrease in the weight of kidney, heart and brain. The spleen and heart demonstrated the maximum mobilization of metals. Comparing the individual trace elements, zinc appeared to be the most active element. None of the metals assayed registered change in RBCs but there was increase in Zn, Fe and Mn concentration in plasma.