Essentiality Toxicity Carcinogenicity Lead(Pb) Exposure Toxicokinetics Toxicity Neurologic, Neurobehavioral, and Developmental Effects in Children Mechanisms of Effects on the Developing Nervous System Peripheral Neuropathy Hematologic Effects Renal Toxicity Lead and Gout Effects on Cardiovascular System Immunotoxicity Bone Effects Reproductive Effects Birth Outcomes Carcinogenicity Other Effects Dose Response Treatment Organic Lead Compounds Mercury (Hg) Exposure Disposition and Toxicokinetics Metabolic Transformation Cellular Metabolism Toxicology Biological Indicators Treatment Nickel (Ni) Exposure Toxicokinetics Essentiality Toxicity Nickel Carbonyl Poisoning Dermatitis Indicators of Nickel Toxicity

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Toxic effects of metals

Cognitive Deficit in 7-year-old Children With Prenatal Exposure to Methylmercury

https://stacks.cdc.gov/view/cdc/37676/cdc_37676_DS1.pdf

Toxicological Profile for Lead

Toxicological profile for arsenic

Cognitive Performance of Children Prenatally Exposed to “Safe” Levels of Methylmercury

The biological monitoring of metals, when used properly, allows total exposure to a particular metal to be measured from various media. It takes into consideration inter- and intraindividual variations in uptake due to differences in metabolism and physical work load and can be used to identify individuals, or groups of individuals, with high exposure or at high risk. As many metals are retained for long periods, biological monitoring may not only provide information on recent exposure, but also on exposure which occurred a long time ago. Under optimal conditions, the concentration of a metal in biological media can be used to assess exposure, the concentration of the metal in the target or critical organ (ie, the organ where the adverse effects are first observed) and the risks for adverse effects. This paper gives an overview of several important aspects of biological monitoring but does not provide detailed information on particular metals.

Biological monitoring of toxic metals.

This paper discusses metal exposure in the male, the nonpregnant female, and the maternal-offspring unit. In the first two situations, the primary targets are the gonads. In the mother-offspring unit, consideration must be given to effects on the fertilized ovum, the growth of the embryo, and, finally, to the fetal and perinatal stages. The central nervous system may be especially vulnerable during development. The placenta also undergoes development, and either the placenta or the fetus may be the primary target. In humans, certain metals may cause abortion or other effects on the conceptus. Effects may also be produced by metal exposure both in utero and in the suckling infant. For example, methylmercury gives rise to a range of effects on the central nervous system at doses lower than those producing damage to the mature nervous system. Effects of lead and arsenic are associated mainly with postnatal exposures during infancy and early childhood, but there is reason to believe from animal experiments that some effects may occur from prenatal exposures to certain metal compounds.

Reproductive and developmental toxicity of metals.

In the previous chapter several examples of toxic compounds that have been used as tools to elucidate the structure and function of the cytoskeleton have been described. These examples were presented in the context of cytoskeletal composition and function. In this chapter, we discuss toxic agents that have been used as tools and present a summary of such compounds. Finally, we review a number of compounds for which evidence strongly suggests that the primary effects involve the cytoskeleton.

The Cytoskeleton: A Target for Toxic Agents

Organization within the cytoplasm has been apparent from the earliest observations of living cells. As techniques improved, so has our appreciation of the complexity involved in the ordered arrangement of cytoplasmic components. The view of cytoskeleton has evolved from one of a static or rigid structure to a more dynamic scaffolding capable of rapid and dramatic restructuring. Several components and functions of the cytoskeleton have been defined in cells. Indeed, the number and diversity of cellular processes subserved by the cytoskeleton are impressive, and it is not surprising that numerous toxic agents have been found to act upon it. For some of these agents, their selective interaction with specific components of the cytoskeleton has led to their use as probes for normal structure and function. For other compounds, the interaction may be less well defined or less specific, but of relevance from an environmental or human health perspective.

Structure and Function of the Cytoskeleton

The field of metal toxicology has received much interest over the past few years. In this volume, the emphasis has been focused on the effects of metals on reproduction and development for several reasons. First, damage to reproduction and development is more likely to have irreversible consequences than damage to most other bodily functions. Indeed, under certain circumstances damage may be passed on to subsequent generations. Irreversible damage sustained before birth may have adverse consequences throughout the entire life span representing a continued burden both to the individual and to society. Second, occupational health and other standards have not always taken into account risks to reproductive and developing tissues. At best, risk to people of childbearing age or to the conceptus has been covered by an arbitrary safety factor; at worst, they have not been taken into account at all. Third, the current tendency in a number of countries is to delay parenthood to later years with the result that the preconception exposure period is increased. Fourth, the current public interest in occupational and environmental exposures during the reproductive years makes it very important to transfer the findings of laboratory, clinical, and epidemiological work to public health officials and administrators, to organized labor and management, and to the public at large.

Polly R. Sager

Papers

Biological monitoring of toxic metals.

Reproductive and developmental toxicity of metals.

The Cytoskeleton: A Target for Toxic Agents

Structure and Function of the Cytoskeleton

An Overview of the Reproductive and Developmental Toxicity of Metals