نتایج جستجو برای: pcb compounds
تعداد نتایج: 231091 فیلتر نتایج به سال:
Due to their bioaccumulative and persistent nature, determination of PCB and organochlorine pesticide levels in human adipose tissue can be a useful biological indicator of exposure. The analytical methods previously used are relatively tedious, labor intensive and not readily amenable to automation. We have combined the use of sweep codistillation cleanup [1] and high resolution gas chromatogr...
Polychlorinated biphenyls (PCBs) as environmental contaminants often cannot be adequately described by reference to Aroclors or to total PCBs. Although there are 209 possible PCB configurations (congeners), perhaps half that number account for nearly all of the environmental contamination attributable to PCBs. Still fewer congeners are both prevalent and either demonstrably or potentially toxic...
Adipose tissue samples from polar bears (Ursus maritimus) were obtained by necropsy or biopsy between the spring of 1989 to the spring of 1993 from Wrangel Island in Russia, most of the range of the bear in North America, eastern Greenland, and Svalbard. Samples were divided into 16 regions corresponding as much as possible to known stocks or management zones. Concentrations of dieldrin (DIEL),...
Spirulina platensis is a blue-green alga used as a dietary supplement because of its hypocholesterolemic properties. Among other bioactive substances, it is also rich in tetrapyrrolic compounds closely related to bilirubin molecule, a potent antioxidant and anti-proliferative agent. The aim of our study was to evaluate possible anticancer effects of S. platensis and S. platensis-derived tetrapy...
In this study, we investigated 17- to 18-year-old boys and girls to determine whether changes in humoral or cellular immunity or respiratory complaints were related to blood serum levels of polychlorinated biphenyls (PCBs) and dioxin-like compounds after lifetime exposure in Flanders (Belgium). We obtained blood samples from and administered questionnaires to 200 adolescents recruited from a ru...
BACKGROUND Polychlorinated biphenyls (PCBs) remain ubiquitous environmental contaminants. Developmental exposures are suspected to impact reproduction. Analysis of mixtures of PCBs may be problematic as components have a complex correlation structure, and along with limited sample sizes, standard regression strategies are problematic. We compared the results of a novel, empirical method to thos...
Microwave heating was employed for preparation of the standard gas of volatile organic compounds (VOCs) and semivolatile organic compounds (semi-VOCs) by using a 1000 W commercial domestic microwave oven and 1 L gas-sampling bulbs. The VOCs investigated were benzene, chloroform, 1,3-dichlorobenzene, tetrachloroethylene, toluene, and 1,1,2-trichloroethane, and the semi-VOCs used were the polychl...
Polychlorinated biphenyls (PCBs) are ubiquitous environmental contaminants that can induce neurological defects in infants and children via placental and lactational transfer. To investigate the lactational transfer of PCBs and compare pharmacokinetic interactions among nonpregnant, lactating mice and suckling pups, quantitative time-course measurements of PCB accumulation in tissues were perfo...
All of the 13 possible polychlorinated biphenyl (PCB) isomers and congeners substituted at both para positions, at least two meta positions (but not necessarily on the same ring) and at two ortho positions have been synthesized and tested as rat hepatic microsomal enzyme inducers. The effects of these compounds were evaluated by measuring microsomal benzo-[a]pyrene (B[a]P) hydroxylase, 4-chloro...
BACKGROUND Early-life chemical exposure may influence immune system development, subsequently affecting child health. We investigated immunomodulatory potentials of polychlorinated biphenyls (PCBs) and p,p'-DDE in infants. METHODS Prenatal exposure to PCBs and p,p'-DDE was estimated from maternal serum concentrations during pregnancy. Postnatal exposure was calculated from concentrations of t...
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