Assessment of chlorpyrifos toxicity on certain organs in rat, Rattus norvegicus.

Chlorpyrifos, an organophosphate insecticide of phosphorothioate group was orally administered to male rats at the doses of 3, 6 and 9 mg kg-1d-1 for 90 days. Animals exposed to high dose (9 mg kg-1d-1) showed signs of toxicity including piloerection, diarrhoea, nose and eye bleeding, reduced body weight and death of animals. Organ weight ratio of different vital organs did not show any change except increase in adrenal weight and decrease in the weight of testes in animals of high dose (9 mg kg-1d-1). A dose dependent inhibition of acetylcholinesterase (AChE) activity in RBC (22-60%) and brain (7-52%) was observed. Microscopic examination of different tissues of male rats showed minor histopathological changes in brain, liver, testis, epididymis and adrenal. The activity of testicular enzymes SDH, G-6-PDH and testicular content of sialic acid and cholesterol were found increased in animals of high dose (9 mg kg-1d-1). There was decrease in RBC counts and levels of hemoglobin (Hb) and hematocrit (HCT) with increase in WBC counts. While, total protein was decreased significantly at all the dose levels in testes and epididymis, glucose level showed a significant decrease at high dose. A dose dependent increase was observed in the level of serum triglycerides. There was no change in sperm motility and sperm morphology at any dose level except a decrease in sperm counts (114.1x 106 g-1 in high dose for group against 158.9 x 106 g-1 controls). It is suggested that chlorpyrifos at 9mg/kg/d dose for 90 days has caused toxicological changes along with mild testicular and spermatotoxic effects in male rats.

Assessment of toxicological effects of mancozeb in male rats after chronic exposure.

Mancozeb, an ethylenebisdithiocarbamate fungicide was administered orally to male rats at doses 0, 500, 1000 and 1500 mg/kg/day for 90, 180 and 360 days produced dose dependent signs of poisoning, loss in body weight gain and mortality. However the signs of toxicity and mortality were more pronounced initially at 0-90 days as compared to 90-360 days of treatment period. A significant increase in the relative weight of liver and slight decrease in the kidney weight were observed in animals exposed to mancozeb (1000 and 1500 mg/kg/day) for 180 and 360 days associated with pathomorphological changes in liver, brain and kidney. Mancozeb has produced significant enzymatic changes in the activities of aspartate aminotransferase (ASAT), alanine aminotransferase (ALAT), alkaline phosphatase (ALP), lactate dehydrogenase (LDH) and acetylcholinesterase (AChE) throughout the period of study in a dose dependent manner. The alterations in the activity of enzymes associated with pathomorphological changes suggest that the chronic exposure of mancozeb produced significant toxicological effects in rats.

Testicular toxicity in rat to repeated oral administration of tetramethylthiuram disulfide (Thiram).

Thiram was administered to male rats through gavage at doses 5, 10 and 25 mg/kg/day for 180 and 360 days. Thiram has caused marginal increase in the relative weight of testes and epididymis and decrease in the weight of seminal vesicle and prostate. Marked degenerative changes were observed in seminiferous tubules together with alterations in testicular enzyme profile. The activity of testicular enzymes such as ACP, SDH and ATPase (Na+ + K+ dependent) was decreased whereas activity of LDH, G-6-PDH and ALP increased. The levels of serum cholesterol and testicular free sialic acid were enhanced, while the level of testicular protein was lowered. It is evident from the present study that long term treatment of thiram at tested dose levels has resulted in dose and time dependent morphological and biochemical changes in testes of rat.

Development effect of technical dimethoate in rats: maternal and fetal toxicity evaluation.

Technical dimethoate was administered orally to pregnant rats through day 6-20 of gestation at doses 3.75, 7.5, 15 and 30 mg/kg/day. Dose of 30 mg/kg/day produced high mortality rate in dams and was not considered for developmental toxicity evaluation. Dimethoate produced enzymatic changes in liver of dams associated with mild pathomorphological changes in liver and brain. Significant fetotoxic effects were not observed at the tested dose levels as evidenced by total number of implantations, percentage resorption, and live fetuses except reduction in fetal weight. Reduced acetylcholinesterase activity in fetal brain and placenta at higher dose levels indicated possible transmigration of dimethoate from dams to fetuses. The absence of anomalies in fetal gross, visceral morphology and skeleton suggests technical dimethoate as non teratogenic in rat at tested dose levels.

Interaction of technical hexachlorocyclohexane and oxydemeton methyl 25 EC to female rats after dermal application.

Technical hexachlorocyclohexane (HCH, 100 mg/kg/day) and oxydemeton methyl 25 EC (125 mg/kg/day) to female rats for 7, 15 and 30 days individually and in combination through skin application caused pathomorphological changes in vital organs and significant enzymatic changes in liver and serum. However changes produced by the two compounds in combination were not suggestive of potentiation effect at the tested dose level in female rats.

An epidemiological study of cannabis abuse among college students of Varanasi.

A study of 4326 students, selected by stratified random sampling and using a self administered questionnaire, revealed that overall cannabis abuse among them was 4.5%. It amounted to a considerable decline in prevalence compared to 10.2% observed in 1976. However, it was noted that this reduction was mainly in occasional users and the proportion of regular users has actually increased in 1986. The prevalence has also shown an increase among girl students. The regular users were mainly from professional colleges, hailing from metropolitan cities and with relatively higher amount of pocket money at their disposal. It was concluded that the observed trends could be due to peer pressures. It was also considered that health education of such students at entry point may help reduce the problem.

Repeated dermal toxicity of technical HCH and methyl parathion (50EC) to female rats (Rattus norvigicus).

Repeated dermal application of hexachlorocyclohexane (HCH; 100 mg/kg/day) or methyl parathion (2 mg/kg/day) individually or in combination for 7, 15 and 30 days produced pathomorphological changes in skin, liver, kidney and brain of female rats along with significant enzymatic alterations in the activity of transaminase, alkaline phosphatase lactic dehydrogenase and acetylcholinesterase. The two insecticides in combination though produced severe toxicity on day 30 than at other periods, the changes were not suggestive of any additive or potentiation effect at the test doses.

Dermal toxicity of hexachlorocyclohexane (HCH) in rabbit.

Application of HCH (25 mg/kg) on dorsal, ventral and thigh regions of the skin of male rabbits resulted in poisoning and mortality of animals. Morphological changes in skin, liver, kidney, testes and cerebellum together with highly significant alterations in serum and liver enzymatic activity and residue in blood suggested that absorption of HCH and its toxicity could be severe when the pesticide comes in contact with the skin of thigh region of body.