Biological (molecular and cellular) markers of toxicity

The overall objective of this study is to evaluate the use of the small aquarium fish, Japanese Medaka (Oryzias latipes), as a predictor of potential genotoxicity following exposure to carcinogens. This will be accomplished by quantitatively investigating the early molecular events associated with genotoxicity of various tissues of Medaka subsequent to exposure of the organism to several known carcinogens, such as diethylnitrosamine (DEN) and benzo(a)pyrene (BaP). Because of the often long latent period between initial contact with certain chemical and physical agents in our environment and subsequent expression of deleterious health or ecological impact, the development of sensitive methods for detecting and estimating early exposure is needed so that necessary interventions can ensue. A promising biological endpoint for detecting early exposure to damaging chemicals is the interaction of these compounds with cellular macromolecules such as Deoxyribonucleic acids (DNA). This biological endpoint assumes significance because it can be one of the critical early events leading eventually to adverse effects (neoplasia) in the exposed organism

Conceptual strategy for design, implementation, and validation of a biomarker-based biomonitoring capability

This document describes a strategy for defining specific objectives for biomarker studies and for designing and implementing a biomonitoring study that focuses on these objectives. In researching this subject, it became clear to the authors that the subject of biomarkers created a great deal of interest among scientists and regulators but that general acceptance of biomarkers as a tool for environmental protection was hampered by lack of a clear notion of how to develop and apply this approach. We intend this document to be a user's guide'' that lays out a logical scheme for applying biomarkers in environmental monitoring. In addition, laboratory and field research components needed to develop and validate fundamental understanding and interpretation of biomarker responses are also described, as is a strategy for evolution of a biomarker-based biomonitoring capability. The document is divided into sections intended to lead the reader to an understanding of how biomarkers can be developed and applied

Biological markers in animals can provide information on exposure and bioavailability of environmental contaminants

Epidemiologic studies of agents present in the environment seek to identify the extent to which they contribute to the causation of a specific toxic, clinical, or pathological endpoint. The multifactorial nature of disease etiology, long latency periods and the complexity of exposure, all contribute to the difficulty of establishing associations and casual relationships between a specific exposure and an adverse outcome. These barriers to studies of exposures and subsequent risk assessment cannot generally be changed. However, the appropriate use of biological markers in animal species living in a contaminated habitat can provide a measure of potential damage from that exposure and, in some instances, act as a surrogate for human environmental exposures. Quantitative predictivity of the effect of exposure to environmental pollutants is being approached by employing an appropriate array of biological end points. 34 refs., 1 fig., 6 tabs