Background: The incidence of obesity has risen dramatically over the last few decades. This epidemic may be affected by exposure to xenobiotic chemicals. Bisphenol A (BPA), an endocrine disruptor, is detectable at nanomolar levels in human serum worldwide. Adiponectin is an adipocyte-specific hormone that increases insulin sensitivity and reduces tissue inflammation. Thus, any factor that suppresses adiponectin release could lead to insulin resistance and increased susceptibility to obesity-associated diseases. Continue reading here
Key words: adipocytes, adiponectin, bisphenol A, estradiol, estrogen receptors, estrogen-related receptors, human adipose explants, obesity.
Background: Polybrominated diphenyl ether (PBDE) flame retardants have been implicated as disruptors of the hypothalamic-pituitary-thyroid axis.
Objective: We examined the effects of dietary exposure to 2,2´,4,4´-tetrabromodiphenyl ether (PBDE-47) —commonly the highest concentrated PBDE in human tissues—on plasma TH levels… Continue reading here
Key words: basic transcription element-binding protein, brain, endocrine disruption, PBDE-47, polybrominated diphenyl ethers, thyroid hormone, thyroid hormone receptor, thyroid-stimulating hormone, thyrotropin.
Objectives: Using the organ culture system we developed previously, we investigated the effects on the development of human fetal testis of one phthalate —mono-2-ethylhexyl phthalate (MEHP) —an industrial chemical found in many products, which has been incriminated as a disruptor of male reproductive function. Continue reading here
Key Words: human fetus, phthalates, testis development
Background: Phthalates are ubiquitous in the environment, but concentrations in multiple media from breast-feeding U.S. women have not been evaluated.
Objectives: The objective of this study was to accurately measure and compare the concentrations of oxidative monoester phthalate metabolites in milk and surrogate fluids (serum, saliva, and urine) of 33 lactating North Carolina women. Continue reading here
Key words: biomonitoring, breast milk, lactation, MAMA study, phthalates, saliva, serum, urine.
Background: A previous study from our laboratory showed that polybrominated diphenyl ethers (PBDEs) were metabolized to hydroxylated PBDEs (HO-PBDEs) in mice and that para-HO-PBDEs were the most abundant and, potentially, the most toxic metabolites. Objective: The goal of this study was to determine the concentrations of HO-PBDEs in blood from pregnant women, who had not been intentionally or occupationally exposed to these flame retardants, and from their newborn babies. Continue reading here
Key words: bromophenols, flame retardants, HO-PBDEs, human blood, metabolites, PBDEs, polybrominated diphenyl ethers.
Objective: We investigated the association between body mass index (BMI) standard deviation score (SDS) and prenatal exposure to hexachlorobenzene, dichlorodiphenyldichloroethylene (DDE) , dioxin-like compounds, and polychlorinated biphenyls (PCBs). Continue reading here
Key words: body mass index, childhood, dichlorodiphenyldichloroethylene, dioxin-like compounds, hexachlorobenzene, obesity, polychlorinated biphenyls.
We report on interviews conducted with participants in a novel study about environmental chemicals in body fluids and household air and dust. Interviews reveal how personal and collective environmental history influence the interpretation of exposure data, and how participants fashion an emergent understanding of environmental health problems from the articulation of science and experience. To the illness experience literature, we contribute a framework for analyzing a new category of embodied narratives—“exposure experience”—that examines the mediating role of science. We update social scientific knowledge about social responses to toxic chemicals. Continue reading here
Background: Perfluorooctanoate (PFOA) and perfluorooctane sulfonate (PFOS) are ubiquitous man-made compounds that are possible hormonal disruptors. We examined whether exposure to these compounds may decrease fecundity in humans.
Methods: Plasma levels of PFOS and PFOA were measured at weeks 4–14 of pregnancy among 1240 women from the Danish National Birth Cohort recruited from 1996 to 2002. Continue reading here
Key words: maternal blood, time to pregnancy, fecundity, perfluorooctanoate, perfluorooctane sulfonate
Background: Hypospadias is one of the most common urogenital congenital anomalies affecting baby boys. Prevalence estimates in Europe range from 4 to 24 per 10,000 births, depending on definition, with higher rates reported from the United States. Relatively little is known about potential risk factors, but a role for endocrine-disrupting chemicals (EDCs) has been proposed.
Objective: Our goal was to elucidate the risk of hypospadias associated with occupational exposure of the mother to endocrine-disruptor chemicals, use of folate supplementation during pregnancy, and vegetarianism. Continue reading here
Key words: endocrine disruptors, hair spray, folate supplementation, hypospadias, occupation.
Background: Resistance to chemotherapy is a major problem facing breast cancer patients, and identifying potential contributors to chemoresistance is a critical area of research. Bisphenol A (BPA) has long been suspected to promote carcinogenesis, but the high doses of BPA used in many studies generated conflicting results. In addition, the mechanism by which BPA exerts its biological actions is unclear. Although estrogen has been shown to antagonize anticancer drugs, the role of BPA in chemoresistance has not been examined.
Objective: The objective of our study was to determine whether BPA at low nanomolar concentrations opposes the action of doxorubicin, cisplatin, and vinblastine in the estrogen receptor-α (ERα) -positive T47D and the ERα-negative MDA-MB-468 breast cancer cells. Continue reading here
Key words: bisphenol A, breast cancer cells, chemotherapeutic agents, cytotoxicity, estrogen receptors.
Background: Widespread human exposure to phthalates, some of which are developmental and reproductive toxicants in experimental animals, raises concerns about potential human health risks. Underappreciated sources of exposure include phthalates in the polymers coating some oral medications.
Objective: The objective of this study was to evaluate whether users of phthalate-containing medications have higher urinary concentrations of phthalate metabolites than do nonusers. Continue reading here
Key words: coating, didanosine, medications, mesalamine, omeprazole, phthalates, theophylline.
Written on 13 February 2009.