M.K.J. Siddiqui

Comparison of polycyclic aromatic hydrocarbon levels in placental tissues of Indian women with full- and preterm deliveries

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous environmental contaminants formed from combustion products of fossil fuels, cigarette smoking and in grilled/smoked foods. They are reported to alter trophoblast proliferation in placenta, in addition to disturbing its endocrine functions, which may be able to increase the risk of preterm delivery in pregnant women. The present study was planned to assess possible involvement of PAHs exposure of pregnant women (measured as placental PAHs concentrations) with preterm delivery cases among women of Lucknow city (India). We performed a case-control study and a total of 60 mothers (n=31 full term and n=29 preterm deliveries) were recruited at a local nursing home of Lucknow, for the period of August 2005-February 2006. Subsequent to parturition, placental tissues from each participant were immediately collected and kept at -20 degrees C until PAHs analyses. Placental tissue PAHs concentrations were determined by HPLC, using a fluorescence detector. Mean+/-SD placental level (61.91+/-12.43ppb) of benzo(b)fluoranthene, a carcinogenic PAH, was found significantly elevated (p<0.05) among women with preterm delivery when compared with the level (23.84+/-7.01) in women having full-term deliveries. In the same way, non-carcinogenic fluoranthene level (325.91+/-45.14ppb) was also detected to be higher in the preterm delivery group compared to 208.6+/-21.93ppb level from the full-term delivery group of women. Additionally naphthalene, acenaphthylene, phenanthrene, anthracene, benzo(a)pyrene and dibenzo(a,h)anthracene levels in placental tissue were also found to be higher in the preterm delivery group of women but the difference did not reach statistically significant levels. This foremost study from India with modest samples size and limited statistical power does not show a substantial involvement of PAHs with preterm delivery, but higher concentrations of placental PAHs detected among preterm delivery group of women could show some possible association with these environmental toxicants. Further study with large sample size, controlled for confounders and great statistical power, is reasonable to elucidate the association of PAHs exposure with preterm delivery of women in India.

Possible mechanism of pesticide toxicity-related oxidative stress leading to airway narrowing

Abstract The study was conducted to assess the magnitude of oxidative stress and lung function abnormalities in 34 male pesticide sprayers on exposure to pesticides in mango plantations. Biochemical studies on blood antioxidant enzymes revealed an unchanged glutathione level and increased level of malondialdehyde (P < 0.001), which indicates that pesticide sprayers may have suffered from oxidative stress. Decreased acetyl-cholinesterase levels (P < 0.001) in sprayers compared to the controls suggest inhibition of cholinesterase activity. The present study shows that pesticide toxicity might lead to oxidative stress and airway narrowing resulting in decreased peak expiratory flow rate.

Monitoring of plasma butyrylcholinesterase activity and hematological parameters in pesticide sprayers.

To evaluate the health impact of spraying organophosphorus insecticides (OPs), 34 male sprayers in the mango belt of Malihabad, a small town located 27 km from Lucknow in North India was selected. Plasma butyryl cholinesterase (PBChE) and complete blood count were assessed among sprayers after spraying pesticides and the findings obtained were compared with those determined in a reference group (n = 18). The most common symptoms observed were burning sensation in the eyes (8.82%), itching/skin irritation (23.52%) and chest symptoms (32.35%) in the exposed workers. Plasma butyrylcholinesterase (PBChE) was significantly decreased in workers. The results indicated significant decrease in the mean value of hemoglobin, hematocrit and platelets count; however, significantly higher count of leukocytes was also observed in the exposed group (sprayers) compared to that observed in the control group (P < 0.05). Monitoring of PBChE in pesticide sprayers could be useful to predict and prevent health hazards of OPs.

Toxicity of endosulfan: Distribution of α- and ß-isomers of racemic endosulfan following oral administration in rats

Abstract Endosulfan was administered orally (2.5 and 7.5 mg/kg) daily to male rats for a period of 60 days. The distribution pattern of α and s-isomers was studied using a gas-liquid chromatography equipped with an electron capture detector. There was a significant increase in liver and lung weights. The testes weight was slightly decreased. No significant change in weights of other tissues was observed. At both dose levels, the concentration of α-isomer was highest in kidney (574 and 1655 ng/g, respectively), followed by lung, ventral prostate, spleen, testes and brain. In the seminal vesicle, epididymis, heart and liver, the concentration of s-isomer was higher than the α-isomer. The results of the study indicated a differential ability to accumulate the two isomers of endosulfan which may help to explain the difference in the toxic potential of the α- and s-isomers.

Organochlorine Pesticides in the Females Suffering from Breast Cancer and its Relation to Estrogen Receptor Status

Breast cancer is one of the most common types of cancer that occurs in females. Approximately 70% of breast tumors express the estrogen receptor. To date, established risk factors for breast cancer are only partially able to explain the causes for this disease. There have always been researchers’ interests in evaluating the role of environmental chemicals, especially those with evidence of being hormonally active agents, which play an important role in breast cancer development. Organochlorine pesticides are one of those chemical which have received the most attentions because of their ability to concentrate onto food chain, fat-soluble and estrogenic activity while remaining persistent in the human body and environment. The present study is an attempt to explore the possibility and role of organochlorine pesticides in the development of estrogen receptor breast cancer. A hospital-based case-control study was administered on 93 women, who underwent various surgeries for breast diseases, to observe the association between organochlorine pesticide exposures with reference to estrogen receptor status in the subjects suffering from breast cancer. Samples of blood, tumor and surrounding adipose tissue of the breast were collected from the subjects with estrogen positive, estrogen negative and benign breast lesions. The samples were then analyzed to determine the presence of organochlorine pesticides by using a gas–liquid chromatography equipped with an electron capture detector. The α, β, γ and δ isomers of HCH (Hexachlorocyclohexane) and metabolites of DDT (Dichlorodiphenyltrichloroethane) such as p,p’-dichlorodiphenyltrichloroethane (p,p-DDT), o,p’- dichlorodiphenyltrichloroethane (o,p’-DDT), p,p’- dichlorodiphenyldichloroethylene (p,p’-DDE), and p,p’-dichlorodiphenyldichloroethane (p,p’-DDD) were frequently detected in the samples at significant level. The result of this study shows that the exposure to potential estrogenic organochlorines may cause the development of estrogen receptor positive breast cancer. A possible mechanism on prognosis of hormone responsive breast cancers needs to be clarified.