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Comparison between Carcinogenicity and Mutagenicity Based on Chemi...

By: Helmut Bartsch

Government Reference Publication

Excerpt: There is increasing evidence to suggest that DNA damage (expressed mainly as mutations) is involved in the induction of many cancers; however, the relevance of the various biological end points used in short-term assays to mechanisms of tumor induction is not known precisely. All test procedures must therefore be validated before they can be used to predict the carcinogenicity of chemicals. Ideally, such validations would he based on correlations between respons...

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Transport of Methylmercury and Inorganic Mercury to the Fetus and ...

By: Birgitta Berglund

Government Reference Publication

Excerpt: It is well established that methylmercury (MeHg) and mercury vapor pass the placenta, but little is known about infant exposure via breast milk. We measured MeHg and inorganic mercury (I-Hg) in blood of Swedish mothers (n = 20) and their infants, as well as total mercury (T-Hg) in breast milk up to 13 weeks postpartum. Infant blood MeHg was highly associated with maternal blood MeHg at delivery, although more than twice as high. Infant MeHg decreased markedly un...

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Reversibility of Cadmium-Induced Health Effects in Iabbiits

By: Kazuo Nomiyama

Government Reference Publication

Introduction: Since Itai-Itai disease was officially established as a cadmium-induced disease (11, more than 50,000 residents of cadmium-polluted areas in Japan have taken health checks for preventing cadmium-induced renal effects and Itai-Itai disease. Episodes of cadmium pollution have been reported in the United States and European countries as well (2,3). Furthermore, some workers exposed to cadmium have been reported to suffer from cadmium health effects (4-6). Once...

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Structure-Toxicity Relationships of Acrylic Monomers

By: John Autian

Government Reference Publication

Introduction: Hundreds of millions of pounds of man-made polymeric materials belonging to the acrylic family are produced each year in this country for a host of industrial and consumer products. The glasslike appearance and nonbreakable property have made these plastics popular for the building, automotive, aerospace, and furniture industries. The dental and medical professions also use these materials for such items as denture plates, artificial teeth, and orthopedic c...

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Sun Exposure and Malignant Melanoma Among Susceptible Individuals

By: Miriam Moseson

Government Reference Publication

Excerpt: Epidemiologic evidence for an etiologic role of solar radiation in malignant melanoma of the skin is derived principally from geographic studies and anatomical site analyses. Geographic studies have linked melanoma to latitude gradients, mean annual ultraviolet light (UV) exposure, measurements of UV flux, and migration patterns, although not consistently in all reports (1-3). Analyses of anatomical site have related increases in incidence rates over time and hi...

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The Protective Effect of Omega-Aminolevulinic Acid Dehydratase 1-2...

By: Hee Seon Kim

Government Reference Publication

Excerpt: Previous studies have suggested that ?-aminolevulinic acid dehydratase (ALAD) types 1-2 or 2-2 are protective against the toxicity of blood lead (PbB) when zinc protoporphyrin (ZPP) levels are low because of differential binding of lead in erythrocytes. The hypothesis is that subjects with the ALAD 1-1 genotype are more susceptible to lead exposure with impaired hematologic synthesis and therefore that iron nutrition is more important in those with the ALAD 1-1 ...

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Tumorigenic Effect of Fibrous Dusts in Experimental Animals

By: F. Pott

Government Reference Publication

Excerpt: The starting point of our investigations was the question whether the tumorigenic effect of asbestos fibers depends on physicochemical properties of the fiber or the shape of the fibers which are characteristic for all kinds of asbestos. For this purpose chemically different fibrous forms were compared to chemically similar dusts having different forms.

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Early-Life Environmental Risk Factors for Asthma : Findings from t...

By: Frank Davis Gilliland

Government Reference Publication

Excerpt: Early-life experiences and environmental exposures have been associated with childhood asthma. To investigate further whether the timing of such experiences and exposures is associated with the occurrence of asthma by 5 years of age, we conducted a prevalence case?control study nested within the Children?s Health Study, a population-based study of > 4,000 school-aged children in 12 southern California communities. Cases were defined as physician-diagnosed asthma...

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Carcinogenicity of 1, 3 : Butadiene

By: Ronald L. Melnick

Government Reference Publication

Introduction: 1,3-Butadiene (CH,=CH=CH=CH,; CAS no. 106-99-O), a colorless, noncorrosive, flammable gas (boiling point: -4.4C), is produced mainly as a co-product in the steam cracking of petroleum fractions for the manufacture of ethylene (1). 1,3- Butadiene is a reactive chemical that can dimerize to 4-vinylcyclohexene or, upon exposure to air, form explosive peroxides (I). The major uses of 1,3-butadiene are in the manufacture of synthetic rubber (such as styrene-buta...

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Oxidant Gases

By: Michael J. Evans

Government Reference Publication

Introduction: The airways of the lung are lined with a layer of ciliated and nonciliated cells (I). In the large airways (trachea, main bronchi, and bronchi), the nonciliated cell population comprises serous, goblet, intermediate, and basal cells. In the small airways (terminal and respiratory bronchioles), Clara cells make up the nonciliated cell population. Goblet, serous, and Clara cells usually protrude above adjacent ciliated cells and contain secretory granules. In...

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Transferable Residues from Dog für and Plasma Cholinesterase Inhib...

By: J. Scott Boone

Government Reference Publication

Excerpt: Exposure of children to pesticides is a major health concern. Children could be exposed to pesticides from carpet, house dust, and toys from treated houses, from clothing of parents who are farm workers and pesticide applicators, and from playing outside in treated lawns and gardens (1?5). One overlooked but important potential source for pesticide exposure to children is pets treated with parasite control products. These products often contain carbamate, pyreth...

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Consumer Hazards of Plastics

By: G. S. Wiberg

Government Reference Publication

Excerpt: After the final manufacturing and processing steps, a considerable portion of the plastic industries products are sold as consumer or household items. Other plastic articles may appear in public places (schools, theaters, stores, transport vehicles), or they could be widely dispersed throughout the work force and thus come into frequent contact with the population. Thus, man in his modern existence is inextricably linked and exposed to the many products of the p...

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Neurologic Symptoms in Licensed Private Pesticide Applicators in t...

By: Beth C. Gladen

Government Reference Publication

Excerpt: Exposure to high levels of many pesticides has both acute and long-term neurologic consequences, but little is known about the neurotoxicity of chronic exposure to moderate levels of pesticides. We analyzed cross-sectional data from 18,782 white male licensed private pesticide applicators enrolled in the Agricultural Health Study in 1993?1997. Applicators provided information on lifetime pesticide use and 23 neurologic symptoms typically associated with pesticid...

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Upper Ottawa Street Landfill Site Health Study

By: Clyde Hertzman

Government Reference Publication

Excerpt: While the site was active, there were four sources of potential human exposure to landfill site emissions. Airborne exposure to vapors, fumes, dusts, and ash may have resulted from on-site burning and from open air release of volatile substances and solid industrial residues at the landfill. For those working at the site, direct skin contact could have occurred. Airborne deposition of landfill site emissions on residential properties left open the possibility of...

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Highly Chlorinated Pcbs Inhibit the Human Xenobiotic Response Medi...

By: Michelle M. Tabb

Government Reference Publication

Excerpt: Polychlorinated biphenyls (PCBs) are a family of persistent organic contaminants suspected to cause adverse effects in wildlife and humans. In rodents, PCBs bind to the aryl hydrocarbon (AhR) and pregnane X receptors (PXR) inducing the expression of catabolic cytochrome p450 enzymes of the CYP1A and 3A families. We found that certain highly chlorinated PCBs are potent activators of rodent PXR but antagonize its human ortholog, the steroid and xenobiotic receptor...

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Perspectives on the Mechanism of Nickel Carcinogenesis Gained from...

By: Max Costa

Government Reference Publication

Excerpt: There is an old Chinese saying that when you drink the water from the well, remember who built it. Although I have only been at the Institute of Environmental Medicine for 2 years, I am very appreciative of the efforts expended by Norton Nelson in establishing the Institute as a leading center of environmental research. It continues to flourish under the directorship of Arthur Upton. As I drink the water here, I will always remember all that Nelson has done. The...

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Guest Editorial Norton Nelson's Legacy : The Science of Environmen...

By: Seymour J. Garte

Government Reference Publication

Excerpt: The field of environmental health science is now a recognized and respected branch of science in American and worldwide academia. One of the pioneers who had a major role in the establishment of environmental health as a true scientific discipline was Norton Nelson, the founder and first chair of the Department and the Institute of Environmental Medicine at New York University (NYU), which now bears his name. Among his many accomplishments, he played a leading r...

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Focus Caution Children at Play

By: Scott Fields

Government Reference Publication

Excerpt: One afternoon last year, Karen Preul of Scottsdale, Arizona, was scooping wood chips from the pile in her backyard to put under her young children?s play set. Such wood chips are made from recycled wood and in Arizona often serve as a cushioning barrier over the states unforgiving soil. While shoveling she noticed a partially shredded rubberized plastic label sticking out of the pile. She pulled out the scrap of label and read the words printed on it: ?WARNING: ...

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The Health Impacts of Exposure to Indoor Air Pollution from Solid ...

By: Daniel M. Kammen

Government Reference Publication

Excerpt: Globally, almost 3 billion people rely on biomass (wood, charcoal, crop residues, and dung) and coal as their primary source of domestic energy (1,2). Biomass accounts for more than one-half of domestic energy in many developing countries and for as much as 95% in some lower income ones (1,3). There is also evidence that in some countries the declining trend of household dependence on biomass has slowed, or even reversed, especially among poorer households (2,4)...

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A Survival-Adjusted Quantal-Response Test for Analysis of Tumor In...

By: Shyamal D. Peddada

Government Reference Publication

Excerpt: In rodent cancer bioassays, groups of animals are exposed to different doses of a chemical of interest and followed for tumor occurrence. The resulting tumor rates are commonly analyzed using a survival-adjusted Cochran-Armitage (CA) trend test. The CA trend test has reasonable power when the tumor-response curve is linear in dose, but it may be underpowered for a nonlinear response. An alternative survival-adjusted test procedure based on isotonic regression me...

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