Neurotoxicology and Behavior William K Boyes PhD

Detailed information about the neurotoxic effects of specific chemical compounds is provided elsewhere in this series of volumes. Therefore, only a brief overview of the major classes of neurotoxic chemicals is provided here. The major classes of environmental and occupational neurotoxicants are metals, insecticides, and organic solvents. There are also many other compounds that produce neurotoxic effects but do not fall within these three categories. 4.1 Metals Numerous metallic compounds have...

Cotton and Other Textile Dusts James A Merchant MD

The term byssinosis was first used by Proust in 1877 to describe respiratory disease among textile workers (3). It arises from the Latin byssus, which means fine and valuable textile fiber known to the ancients, usually referring to flax, but also cotton, silk, and other natural textile fibers. While Ramazzini was the first to describe asthma and chronic respiratory disease arising from the processing of textiles, there are abundant important historical descriptions of respiratory disease among...

Cited Publications

Dupre, Report of the Royal Commission on Matters of Health and Safety Arising from the Use of Asbestos in Ontario, Ontario Government Book Store, Toronto, Canada, 1984, pp. 87, 89-93. 2 A. A. Hodgson, Scientific Advances in Asbestos, 1967-1985, Anjalena Publication, Crowthorne, United Kingdom, 1986. 3 V. Timbrell, The Inhalation of Fibres, in H. Shapirio, Proceedings of the International Pneumoconiosis Conference, Pergamon Press, New York, 1970, pp. 3-9. 4 R. E. G. Rendall, The Data...

Use of Toxicological Data in Evaluating Chemical Safety Gloria Rachamin PhD

A large volume of toxicological data is required to identify and characterize the nature of the toxic effects of chemicals and to predict their potential risk to humans under given exposure conditions. To evaluate chemical safety, regulatory agencies use data from both human and animal toxicological studies. Such data can be obtained from various sources, including published literature, computerized databases, and submissions from chemical manufacturers. Four main categories of toxicological...

Threshold Dose Lowest Observed Adverse Effect Level LOAEL and No Observed Adverse Effect Level NOAEL

A normally distributed sigmoid curve approaches 0 as the dose is decreased but theoretically never passes through 0 . The lowest dose of a chemical that evokes a quantal response is called the threshold dose, even if it cannot be measured experimentally. The identification of a threshold dose depends on the specific response measured, the sensitivity of the measurement, and the number of subjects. The LOAEL is the lowest experimentally measured dose that produces a toxic effect. The NOAEL is...

Ionizing Radiation Roy E Albert MD

The health significance of radionuclides lies in their ability to enter the body where their biological behavior is determined by their chemical properties and their radioactive properties allow them to irradiate tissues in which they localize. Thus alpha- and low energy beta-emitting isotopes, which are essentially innocuous outside the body, can produce radiation damage when taken into the body. The two principle routes of exposure to nuclides are inhalation and ingestion. If the inhaled...

Occupational Chemical Carcinogenesis Ronald L Melnick PhD

3.0 Risk Assessment and the Development of Occupational Exposure Standards Section 2.0 focused on methods to identify carcinogens and criteria used to evaluate the strength of evidence on whether an agent poses a human cancer risk. Hazard identification is the first step of the risk assessment process and is concerned with whether an agent can cause an adverse health outcome. Sources of information for this determination include epidemiological studies, animal studies, short-term assays, and...

Table 52 Some Key Definitions for Hazard Identification

ADAPTIVE EFFECT enhances an organism's performance as a whole and or its ability to withstand a challenge. An increase in liver weight due to an increase in hepatic smooth endoplasmic reticulum is an example of an adaptive effect, if hepatic metabolism reduces the chemical's toxicity. COMPENSATORY EFFECT maintains overall function without enhancement or significant cost. Increased respiration due to metabolic acidosis is an example of a compensatory effect. CRITICAL EFFECT is the first adverse...

Homozygote

Sickle cell anemia resistance to malaria G6PD deficiency resistance to malaria Congenital adrenal hyperplasia protection against Hemophilus influenzae B infections Tay-Sachs disease resistance to tuberculosis High pepsinogen I (gastric secretion) resistance to tuberculosis Idiopathic hemochromatosis protection against iron loss (menses) Non-insulin-dependent diabetes mellitus protection against intermittent limited food intake Cystic fibrosisa resistance to cholera toxin and or bronchial asthma...

Reproductive and Developmental Toxicology Carole A Kimmel PhD Judy Buelke Sam

Reproductive toxicology encompasses the study of a wide variety of chemical and physical agents and their effects on the structure and function of the male and female reproductive systems, the ability to conceive and reproduce, the nurture of the young during pregnancy and lactation, and the development of offspring to grow, mature, and reproduce (Fig. 3.1). Developmental toxicology involves the study of the effects of preconceptional, prenatal, and or postnatal exposures up to the time of...

Mccarthy Aluminum Powder Silicosis

Ingested aluminium using Al Proc. 3rd Int. Con. Aluminum Health, Miama, FL, 1996, pp. 30-34. 28 E. Nieboer et al., Health effects of aluminium A critical review with emphasis in drinking water. Environ. Rev. 3, 29-85 (1995). 29 W. D. Kaehny, A. P. Hegg, and A. C. Alfrey, Gastrointestinal absorption of aluminum from aluminum-containing antacids. N. Engl. J. Med. 396, 1389 (1977). 30 A. C. Alfrey, Physiology of aluminum in man. In H. J. Gitelman, ed., Aluminum and Health, Dekker, New York, 1989,...

Bloodborne Pathogens In the Workplace Debra L Hunt Jerry J Tulis MD

On June 5, 1981, the CDC reported several cases of Pneumocystis carinii pneumonia in young male homosexuals (7). Several weeks later, Kaposi apos s sarcoma was reported in 26 male homosexuals, some of whom also were diagnosed with P. carinii pneumonia (8). These reports represented the first recognized cases of what is now defined as acquired immunodeficiency syndrome (AIDS). Seventeen years later, in June 1998, over 657,077 AIDS cases had been reported to the CDC among persons of all ages in...

Ecogenetics The Study of Gene Environment Interactions Daniel W Nebert Amy L Roe PhD

Around 1930-1970, DMEs were considered as a liver detoxification system responsible for breaking down drugs and other hydrophobic environmental chemicals for excretion. It is now clear that (1) at least some of these DMEs are located in every eukaryotic cell, (2) almost all DMEs have endogenous compounds as their natural substrates, and (3) many of these DMEs have existed in evolution prior to the divergence of bacteria from eukaryotes, indicating that these DMEs have been responsible for...

Petroleum Coal Tar and Related Products Richard W Niemeier PhD

In 1619, Dudley discovered that when certain (bituminous) coals wre heated in the absence of oxygen, referred to as charking, coak was produced, which could be substituted for wood charcoal. By 1800, commercial products included coke-oven gases (illuminating gas), a low-boiling distillate known as coal naphthas (light oil of tar, also known as light liquid naphtha or benzine), and a buttery-solid condensation product containing carbon, naphthaline, paranaphthaline or anthracene, paraffin,...

Table 101 IARC Weight of Evidence Classification for Carcinogenicity

Group The agent is carcinogenic to humans 1 sufficient evidence of carcinogenicity in humans The agent is probably carcinogenic to humans limited evidence in humans and sufficient evidence in experimental animals only limited evidence in humans or only sufficient evidence in experimental animals in the presence of other supporting data Group The agent is possibly carcinogenic to humans 2B limited evidence in humans in the absence of sufficient evidence in experimental animals sufficient...

Table 73 One Possible Classification of Human Ecogenetic Differences

Less enzyme defective protein N-acetylation polymorphisms (NAT2, NAT1) Increased susceptibility to chemical-induced hemolysis (G6PD deficiency) (G6PD) a Antitrypsin protease inhibitor (PI) , defective alleles associated with increased toxicity by cigarette smoke a Antichymotrypsin (AACT), mutant alleles also associated with more toxicity by cigarette smoke P450 monooxygenase polymorphisms (oxidation deficiencies) debrisoquine (CYP2D6), phenytoin (CYP2C9, CYP2C19), nifedipine (CYP3A4), coumarin...