Evaluation of comparative effect of pre- and posttreatment of selenium on mercury-induced oxidative stress, histological alterations, and metallothionein mRNA expression in rats.

To evaluate the effect of pre- or posttreatment of selenium (6 micromol/kg b.w., single intraperitoneal injection) in mercury intoxication, rats were exposed to mercury (12 micromol/kg b.w., single intraperitoneal injection). Exposure to mercury resulted in induced oxidative stress in liver, kidney, and brain tissues. Marked changes in serum biochemical parameters together with alterations in histopathology and an induction in metallothionein-I and metallothionein-II mRNA expression in the liver and kidney were observed. Pretreatment with selenium to mercury-exposed animals had protective effect on the liver, whereas posttreatment had partial protection on restoration of altered oxidative stress parameters. In the kidney, pretreatment with selenium showed partial protection on restoration of altered biochemical parameters, whereas no protection was observed in posttreatment. The pretreatment with selenium resulted in restoration of mercury-induced metallothionein-I and metallothionein-II mRNA expression, which was completely restored in the liver whereas partial restoration was observed in the kidney. Posttreatment with selenium resulted in further induction in metallothionein-I and metallothionein-II mRNA expression in the liver and kidney. In the brain, selenium showed partial protection on alerted biochemical parameters. Results indicate that pretreatment with selenium is beneficial in comparison to posttreatment in mercury intoxication. Thus, dietary intake of selenium within safe limit may, therefore, enable us in combating any foreseen effects due to mercury exposure.

Level of organochlorine pesticide residues in dry fruit nuts.

The use of pesticides on cash crops and exportable food commodities had always been a serious concern. Fruits form one of the important constituents of human diet, in that they give one third of the requirement of calories, vitamins, and minerals. This study has been carried out to determine the level of organochlorine pesticides namely HCH, DDT and Endosulfan in raw fruit nuts. Nuts have proteins and high level of fat content. These properties of nuts attract organochlorine pesticides to accumulate. The analysis of organochlorine pesticide residues in commonly used dry fruits like Cashewnut, Walnut, Coconut, Chilgoza, Chironji, Makhana, Resins, Apricot, Almonds, Date palm, Pistachio nut collected from local market of Lucknow India has indicated presence of very low level of HCH (0.007-1.328 mg kg(-1)), DDT(ND-0.140 mg kg(-1)) and Endosulfan (ND-0.091 mg kg(-1)). There are no MRL values established for nuts in the country. This finding is based on a smaller number of samples, which however suggest that the presence of low level of DDT, HCH and Endosulfan might be due to environmental rather than direct exposure.

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(-1) d(-1) for 90 days. Animals exposed to high dose (9 mg kg(-1) d(-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(-1) d(-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(-1) d(-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 (114.1 x 10(6) g(-1) in high dose for group against 158.9 x 10(6) g(-1) controls). It is suggested that chlorpyrifos at 9 mg/kg/d dose for 90 days has caused toxicological changes along with mild testicular and spermatotoxic effects in male rats.

Lack of toxic effect of technical azadirachtin during postnatal development of rats.

Azadirachtin, a biopesticide has been evaluated for its possible toxic effects during postnatal development of rats over two generations. Rats were fed 100, 500 and 1000ppm technical azadirachtin through diet which is equivalent to 5, 25 and 50mg/kg body weight of rats. Technical azadirachtin has not produced any adverse effects on reproductive function and data were comparable to control animals over two generations. There were no toxicological effect in parent rats as evidenced by clinical signs of toxicity, enzymatic parameters like AST, ALT, ALP, S. bilirubin, S. cholesterol, total protein and histopathology of liver, brain, kidney and testes/ovary. The litters of F(1B) and F(2B) generations were devoid of any morphological, visceral and teratological changes. The percent cumulative loss and growth index of pups were also comparable to respective controls in successive growth period of 0, 4, 7, 14 and 21 days in two generations. There were no major malformations in fetuses while some insignificant minor skeletal variations like missing 5th sternebrae and bipartite thoracic centre found were not compound or dose related. No significant pathomorphological changes were observed in liver, kidney, brain and gonads of F(2B) pups. In conclusion rats fed technical azadirachtin showed no evidence of cumulative effects on postnatal development and reproductive performance over two generations. Absence of any major adverse reproductive effects in adults as well as in 21 days old pups of F(2B) generation suggest the safe use of technical azadirachtin as a biopesticide.

Residues of DDT and HCH in wheat samples collected from different states of India and their dietary exposure: A multicentre study.

Under a multicentre study conducted by the Indian Council of Medical Research, 1712 samples of wheat grain/flour were collected from urban and rural areas in 11 states representing different geographical regions of India. These samples were analysed for residues of DDT (2,2-bis (p-chlorophenyl)-1,1,1-trichloro ethane) and different isomers of HCH (1,2,3,4,5,6-hexachloro cyclohexane, a mixture of isomers) by gas-liquid chromatography. Residues of DDT were detected in 59.4% of 1080 samples of wheat grain and in 78.2% of 632 samples of wheat flour. Different isomers of HCH were present in about 45-80% of the samples of wheat grain/flour. Medians of DDT and total HCH, respectively, for pooled samples of wheat grain were 0.013 and 0.035 mg kg(-1), while those for wheat flour were 0.01 and 0.02 mg kg(-1). Estimated daily intakes of DDT and different isomers of HCH through the consumption of wheat contaminated at their median and 90th percentiles constituted a small proportion of their acceptable daily intakes. Amongst the pesticide residues analysed, statutory maximum residue limits have been fixed only for gamma-HCH in wheat in India, as 0.1 mg kg(-1) in wheat grain and zero in wheat flour. Residue levels of gamma-HCH exceeded these maximum residue limits in five of 1080 samples of wheat grain and in 340 of 632 samples of wheat flour. The failure to meet the requirement of the gamma-HCH maximum residue limit in large number of wheat flour samples was attributed to the fixation of practically unachievable zero limit. Comparing the previous studies and the present one, the levels of residues of DDT and HCH in wheat were significantly decreased.

Effect of dermal exposure to paraphenylenediamine and linear alkylbenzene sulphonate in guinea pigs.

OBJECTIVE: To study the effects of paraphenylenediamine (PPD) and linear alkylbenzene sulphonate (LAS) alone and in combination on the skin. METHODS: Forty-eight guinea pigs were divided equally into 4 groups and exposed to PPD (4 mg/kg), LAS (12 mg/kg) and PPD (4 mg/kg) plus LAS (12 mg/kg) for 30 days. The biochemical parameters such as acid phosphatase, gtutathione-s-transferase, glutathione peroxidase, glutathione, lipid peroxidation and histamine contents in exposed skin were estimated. The histopathological examination of the exposed skin was also carried out. RESULTS: The skin enzymes, lipid peroxidation, and histamine increased while glutathione decreased in skin. The simultaneously exposed group showed additive toxic effects. The histopathological examination showed severe hyperkeratosis, thickening of collagen fibres and vacuolisation of epidermal cells in PPD plus LAS exposed skin. CONCLUSION: The findings of the present study suggest that simultaneous exposure to PPD and LAS has additive toxic effects.

Assessment of embryo/fetotoxicity and teratogenicity of azadirachtin in rats.

To evaluate the potential effect of exposure to azadirachtin technical 12% throughout major organogenesis, rats were fed orally with 500, 1000 and 1500 mg/kg/day azadirachtin on gestation days 6-15 and examined for evidence of embryo/fetotoxicity and teratogenic effects. Technical azadirachtin at different doses did not produce any significant adverse effects in reproductive parameters. Significant embryo/fetotoxic effects were not observed at tested dose levels as evidenced by total number of implantations, post-implantation loss and fetal weight. There were no major malformations, while some minor variants found in high doses were not compound or dose related. The absence of anomalies in fetal gross, visceral morphology and skeleton suggests that technical azadirachtin is not teratogenic in rats at the doses tested.

Organochlorine pesticides in carcinoma of the gallbladder: a case-control study.

Carcinoma of the gallbladder is the third most common malignancy of the gastrointestinal tract in the Eastern Uttar Pradesh and Western Bihar regions of India. The main source of drinking water in this region is the river Ganges, which is heavily polluted with agricultural pesticides. Organochlorine pesticides were estimated in bile by gas liquid chromatography in 60 patients (30 carcinoma of the gallbladder and 30 cholelithiasis) to observe its association with aetiopathogenesis of carcinoma of the gallbladder. The mean biliary concentration of benzene hexachloride (BHC) was found to be significantly higher in carcinoma of the gallbladder (0.0471 ppm) than in cholelithiasis (0.0352 ppm) (P < 0.04). The mean biliary concentration of dichlorodiphenyltrichloroethane (DDT) was also significantly higher in carcinoma of the gallbladder (0.418 ppm) than in cholelithiasis (0.0103 ppm) (P < 0.03). Biliary aldrin and endosulfan concentrations were higher in carcinoma of the gallbladder (0.0008 and 0.00132 ppm) than in cholelithiasis (0.0005 and 0.0126 ppm) but the difference was statistically not significant (P < 0.06 and P < 0.9). The levels of pesticides in blood did not show significant differences in either carcinoma of the gallbladder or cholelithiasis. Significantly high biliary BHC and DDT concentrations suggest that these pesticides might be associated with gallbladder carcinogenesi.

Azadirachtin, a neem biopesticide: subchronic toxicity assessment in rats.

Azadirachtin, a biopesticide obtained from neem, was subjected to subchronic toxicological testing to document its safety for use as a pesticide. Azadirachtin technical 12% orally administered to male and female rats at doses of 500, 1000 and 1500 mg/kg/day for 90 days did not produce any signs of toxicity, mortality, changes in tissue weight, pathology and serum and blood parameters. It can be suggested that azadirachtin at the highest dose tested is well tolerated by rats of both sexes. The highest dose, 1500 mg/kg, can be used as a basal dose for the determination of the no-observed-effect level (NOEL) of azadirachtin to calculate its safety margin.

Subchronic oral toxicity of a combination of insecticide (HCH) and herbicide (ISP) in male rats.

Rats were treated orally with technical hexachlorocyclohexane (HCH, 12.5, 25 and 50 mg kg-1 day(-1)) and technical isoproturon (ISP 22.5. 45 and 90 mg kg-1 day(-1)) daily for a period of 90 days alone and in combination. Treatment with HCH alone showed mild to severe toxicity and death. Significant changes occurred in liver weight, clinical enzyme profiles, haematological parameters and pathomorphological changes. Treatment with ISP alone did not produce such changes. The combination of HCH and ISP produced changes not suggestive of synergism.

A limited three-generation reproduction study on hexachlorocyclohexane (HCH) in rats.

Dietary feeding of technical hexachlorocyclohexane (HCH) at 125 and 250 ppm to rats have not shown any adverse effects on reproductive function and were comparable to control animals in a three-generation study. There were no major malformations, while some minor variants found were not compound or dose related. Despite some mild toxicological effects in rats of the P(0) generation, the litters of F(1B), F(2B) and F(3B) generations were devoid of any morphological or teratological changes. The presence of HCH residues in vital tissues of F(3B) pups have indicated transmigration of HCH in preceding generations but not to an extent that produced adverse effects.

Assessment of the no-observed-effect level (NOEL) of quinalphos in pregnant rats.

Technical quinalphos (0.5, 1.5, 2, 3 or 4.5 mg/kg body weight) was administered orally to pregnant rats from day 6-15 of gestation. At 3 and 4.5 mg/kg/day, quinalphos produced significant changes in hepatic ALT, ALP and serum ALT, AST, ALP and LDH activity along with hepatocellular changes in dams. The AchE activity in brain and red blood cells was also significantly inhibited at these two doses. At 0.5, 1.5 and 2 mg/kg/day, however, quinalphos did not produce any such changes. Up to a dose of 2 mg/kg/day there was no foetotoxic or teratogenic effect, as evidenced by number of implantation sites, percent resorption, foetal weight, morphological, visceral and skeletal evaluations. Hence, 2 mg/kg body weight of quinalphos could be considered as the no-observed-effect level (NOEL) on foetal and maternal toxicity in rats.

Phototoxicity of quinalphos under sunlight in vitro and in vivo.

The phototoxicity of quinalphos (QP) under sunlight was studied by investigating skin sensitization, mouse tail and ear swelling tests and generation of activated oxygen species (AOS). Quinalphos, at an oral dose of 5 mg/kg to the mouse, did not produce any change in water content of the tail, but produced ear swelling under sunlight (60 min). The pesticide did not produce any skin sensitization reaction when applied on depilated skin of guinea pigs (100-500 microg/cm2) and irradiated under sunlight (60 min). Furthermore, the compound produced a significant amount of AOS such as singlet oxygen (1(O2)) and superoxide anion radical (O2- under sunlight. The production of AOS was both concentration (1-20 microg/ml) and irradiation time (0-40 min)-dependent. The generation of AOS was also confirmed by using quenchers of singlet oxygen (sodium azide and DABCO) and superoxide anion radical (SOD).

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.

DDT and HCH residues in dairy milk samples collected from different geographical regions of India: a multicentre study.

Under a multicentre study conducted by the Indian Council of Medical Research, 2205 samples of dairy milk were collected from rural and urban areas of 12 states representing different geographical regions of India. These samples were analysed for residues of DDT and different isomers of HCH by gas-liquid chromatography. Analytical quality assurance between various participating laboratories was ensured through analysis of check samples. The residues of DDT and HCH were detected in more than 80% of samples analysed. Concentrations of DDT residues, alpha-HCH, beta-HCH, gamma-HCH and delta-HCH exceeded their maximum residue limits prescribed by the Ministry of Health and Family Welfare of the Indian Government in 37, 21, 42, 28 and 4% of the samples, respectively. Median values of DDT and HCH found in dairy milk in India were more than the corresponding values reported from most other countries. The results showed significant variations in the incidence as well as level of these contaminants in dairy milk from different regions of the country.

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.

Induction of gonadal toxicity to male rats after chronic exposure to mancozeb.

Mancozeb-a fungicide of ethylenebisdithiocarbamate group was orally administered at doses of 500, 1,000 and 1,500 mg/kg body weight/day for 30, 90, 180 and 360 days. Signs of toxicity mortality pattern and loss in body weight were observed in dose dependent manner. However, signs of intoxication and mortality pattern were more pronounced till the exposure of 90 days. A significant increase in testes and decrease in epididymis weight were associated with degeneration in seminiferous and epididymal tubules with loss of sperms. The decrease in gonadal acid phosphatase (ACP), succinic dehydrogenase (SDH) and increase in alkaline phosphatase (ALP), lactate dehydrogenase (LDH) activity were observed with increased serum cholesterol. Sialic acid and protein content of testis and epididymis were also decreased in dose dependent manner. The study has thus indicated marked biochemical and pathological changes in gonads of male rats after chronic exposure to mancozeb.