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Histopathology of Early Effects of Oral Cadmium in the Rat Kidney

By: E. Aughey

Government Reference Publication

Introduction: The mammalian kidney is a target organ for a wide variety of toxic agents due to its prime function as a blood filter during the excretory process. Cadmium (Cd) is a toxic heavy metal increasingly being recognized as a potential environmental pollutant. Renal tubular damage occurs with long-term exposure and the accumulation of Cd in the kidney after the critical tissue level is reached (13). Some of the Cd carried to the kidney in the blood plasma is bound...

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Acceptability of Human Risk

By: Roger E. Kasperson

Government Reference Publication

Excerpt: Recent events have conspired to intensify the societal discussion of the level of risk appropriate for the control of technological hazards. The Supreme Court decision on the OSHA regulation to control the exposure of workers to benzene, for example, called for a determination of the presence of significant risks that could be reduced by the new standard, but not that the work environment be made risk-free (I) . The recent Reagan Administration proposal to relax...

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Comparison of Gas-Phase Free-Radical Populations in Tobacco Smoke ...

By: Thomas M. Flicker

Government Reference Publication

Excerpt: Free-radical reactions dominate the combustion process of organic materials. Primary combustion radicals are reactive species and most have lifetimes in air of less than a microsecond. Despite their reactivity, free radicals have been detected in cigarette smoke as long as 5 min after combustion (1?3). Studies have shown that the radicals detected in aged cigarette smoke and other postcombustion gases are not remnants of the actual combustion process, but rather...

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The Fish Gill : Site of Action and Model for Toxic Effects of Envi...

By: David H. Evans

Government Reference Publication

Excerpt: The increasingly obvious effects of pollution of the biosphere in general and aquatic ecosystems in particular are known to everyone and are the subject of daily accounts in the popular press as well as textbooks (1) and scientific monographs (2,3). It is the intent of this short review to: (a) examine the morphology and physiology of the fish gill epithelium and its underlying vasculature, (b) briefly review selected data which indicate that a variety of toxica...

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Background Information on High Voltage Fields

By: David E. Janes

Government Reference Publication

Introduction: The high-voltage fields that are of current environmental interest are the fields associated with the transmission of electricity. Since electricity is often generated at sites that are remote from the points of consumption, some means of electrical transmission is required. Most of this transmission is accomplished with overhead transmission lines. The increase in the demand for power and the economies that can be realized when electricity is tansmitted at...

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The Eye and Visual Nervous System : Anatomy, Physiology and Toxicology

By: Connie S. Mccaa

Government Reference Publication

Excerpt: Anatomy of the Eyeball The eye consists of a retinal-lined fibrovascular sphere which contains the aqueous humor, the lens and the vitreous body as illustrated in Figure 1. The retina is the essential component of the eye and serves the primary purpose of photoreception. All other structures of the eye are subsidiary and act to focus images on the retina, to regulate the amount of light entering the eye or to provide nutrition, protection or motion. The retina m...

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Carcinogenesis Studies in Rodents for Evaluating Risks Associated ...

By: James Edward Huff

Government Reference Publication

Introduction: The increase in public awareness that fish and shellfish canbt in polluted waters contain potentially dangerous amounts of t&c and carcinogenic chemicals (1-4) has led to greater attempts to determine the possible health hazards from eating contaminated mollusks, crustaceans, and fish. Concern on the East Coast was heightened when a large percentage of winter flounder (Pseudopleumnectes americanus) taken from Boston Harbor was found to have visible lesions ...

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Metabolic Activation of Benzo(A)Pyrene in Sencar and Balbic Mouse ...

By: William M. Baird

Government Reference Publication

Excerpt: The susceptibility of rodents to tumor induction by carcinogenic chemicals depends on both the species and strain of rodent as well as on the particular type of carcinogen and the route of administration. The two-stage initiation-promotion protocol in mouse skin has been used for over 40 years as an assay for detecting tumor initiators and promoters (1). The speed and sensitivity of this assay were greatly increased by Boutwell and co-workers by breeding strains...

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Air Pollution Underground Fires Surface

By: Lisa Saffron

Government Reference Publication

Excerpt: Uncontrolled fires burning in underground and surface coal deposits in numerous countries, including China, India, and Indonesia, are emitting large amounts of greenhouse gases and other pollutants into the atmosphere. These pollutants may pose other grave environmental hazards. In China alone, about 120 million tons of coal are consumed in uncontrolled fires each year, says Andries Rosema, director of the Environmental Analysis and Remote Sensing Company in Del...

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Noise and Stress : A Comprehensive Approach

By: Jack C. Westman

Government Reference Publication

Excerpt: Thr fundamental purposes of hearing arc to alert and to warnra rurult sound directly evokes emotions and ac:tions. The proeessin of sound by the hrain is outlined tab provide a hiolouiral and svcholonieabl asis for understandinr the way in which sound can become a human stressor.

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The Carcinogenicity of Chromium

By: Tor Norseth

Government Reference Publication

Excerpt: The general toxicology of chromium compounds has been reviewed by the National Academy of Sciences (1) and by the National Institute of Occupational Safety and Health (2). The carcinogenic properties of chromium compounds have been specifically reviewed by the International Agency for Research on Cancer (3). More recently, several condensed reviews of the toxicology of chromium have been published (4-81, and possible mechanisms of the carcinogenic effect have be...

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Identification and Characterization of Populations Living Near Hig...

By: Daniel Wartenberg

Government Reference Publication

Excerpt: A complementary approach used ro investigate the association between electric and magnetic fields and cancer has been the study o f tnortality patterns o f workers with high occupntional exposure to electric and magnetic fields. The excess rates of leukemia and brain cancer deaths observed in these studies [e.g., Theriault (11)I have substantiated concern about exposure to electric and magnetic Gelds. But because the actual magnitude of electric and magnetic fie...

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Chemistry and Toxicology of Quinoxaline, Organotin, Organofluorine...

By: Charles O. Knowles

Government Reference Publication

Excerpt: Several of the newer synthetic organic or second generation acaricides are widely used for control of phytophagous mites and ticks. Certain of these compounds also have insecticidal and fungicidal activity. This paper reviews some of the existing data derived from studies of the chemistry and toxicology of the quinoxaline, organotin, organofluorine, and formamidine compounds.

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Alveolar Type II and Clara Cells : Isolation and Xenobiotic Metabolism

By: Theodora R. Devereux

Government Reference Publication

Excerpt: Until the mid 1970s, very little research involving isolated pulmonary cells was reported. Separation of pulmonary cells has been a difficult problem because of the complex and heterogeneous nature of the lung. The lung contains some 40 varied cell types (1). However, with the development of advanced biochemical tools and equipment, new techniques have been adapted for the isolation of several pulmonary cell types, including the alveolar Type I1 cell and the non...

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Silent Advances

By: John Muir

Government Reference Publication

Excerpt: A growing body of research shows that gene silencing is a critical component of many diseases. In particular, scientists continue to learn more about how enzymes known as histone deacetylases, or HDACs, work to silence genes. Better understanding of how HDACs silence genes is particularly relevant to understanding, and perhaps better managing, diseases characterized by abnormal cell growth, such as cancer and neurological disorders.

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Ushering in the New Toxicology : Toxicogenomics and the Public Int...

By: John M. Balbus

Government Reference Publication

Excerpt: New scientific tools spawned by the genomics revolution promise to improve our ability to identify causative factors in human diseases. But as these new tools elucidate the complex interactions between chemical toxins and biologic systems, the strain on traditional ways of understanding toxic effects grows. Despite major advances in the science and technology of these new toxicogenomics tools, scientific and political complexities threaten to delay the use of to...

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Chemically Contaminated Aquatic Food Resources and Human Cancer Ri...

By: United Nations

Government Reference Publication

Excerpt: It was the original intent of the Steering Committee to include a fourth session, to be attended by all conferees and devoted to identifying the most urgent research needs pertinent to the subject of the conference. Time limitations unfortunately precluded this possibility. The Committee therefore invited the conferees to submit, subsequent to the meeting, their comments and suggestions regarding future research needs. These comments and others brought forward i...

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Rnai : Whats All the Noise about Gene Silencing

By: Ernie Hood

Government Reference Publication

Excerpt: It all began with petunias. In the late 1980s, geneticist Richard Jorgensen, then working at a California plant biotechnology company, attempted to deepen the hue of purple petunias by introducing more of the gene that gives them their color, in the form of double-stranded RNA (dsRNA). Instead, some of the engineered flowers became variegated and others turned white, indicating that expression of both the introduced pigmentation gene and its homologous endogenou...

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The Risk Linked to Ionizing Radiation : An Alternative Epidemiolog...

By: Raphael Lagasse

Government Reference Publication

Excerpt: Setting limits for exposure doses to prevent adverse outcomes in humans is an old debate in radioprotection (1). Various threshold values have been proposed. Historically, the first permissible dose proposed was linked to deterministic effects of ionizing radiation. These values were around 500 mSv (50 rems). The threshold doses at which nonstochastic effects appear were based on these figures. They have not been modified to date and represent the dose limitatio...

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A High-Yield Sampler for Toxicological Characterization of Complex...

By: Edward L. Kruzel

Government Reference Publication

Introduction: Combustion systems emit complex organlc mixtures showing toxicolo-ei cal activilv in bacterial cells (.1 -,3, .h uman cells 1% 4.3. .,. and rodents (W. F. Bush... Jr... w. rsonal communication). Pmgress in emissions monitoring and control has been encou&ing. However, combustion will remain of interest as an important potential source of envimnmental toxicants because of continued need for fossil and biomass-fueled stationary and mobile comwastes.

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