Methodological dose-effect relations

Both the development and application of bioindicators present a number of methodological considerations. One key requirement is to relate dose/effects studies in the laboratory, and residne levels/efifects studies in the field. For many years, these stndies were condncted by different groups of scientists, and the cotmections were not made (Eisler 1987). Ideally, we should use bioindicators where there are clear links between exposnre levels, tissue levels, and effects (Burger and Gochfeld 2003). The most nseful bioindicators of those we suggest are those where the cotmections have been clearly made. 

Therefore, if human administration of MDMA-like compounds is considered clinically efficacious, further studies are needed to determine whether there may be a safe dose range or if there may be related compounds with less potential toxicity and similar beneficial effects. The studies reported here, and in other papers in this volume, describe several methodological approaches and well-characterized parameters to study the effects and... 

CDDs and the structurally related CDFs and dioxin-like PCBs are of concern to ATSDR because of the potential of these chemicals to harm health at relatively low doses. As discussed in Section 2.5, many of the toxic effects of these compounds appear to be mediated by a common mechanism, and CDDs frequently occur with CDFs in the environment. Therefore, due to the common mechanism of toxicity, total toxicity of a CDD/CDF mixture probably results from the added contribution (not necessarily linear) of both classes of chemicals. Because of this, the complex issue of appropriate methodology for quantitatively assessing health risks of CDDs and CDFs is currently being evaluated by ATSDR. Additional information on toxic interactions between CDDs and CDFs, as well as PCBs, would facilitate health risk assessment of this class of chemicals. 

We have found the monkey to be an extremely useful animal model with which to explore the effects of lead (as well as other neurotoxic agents) on the developing organism. The use of sophisticated behavioural methodology has allowed detection of clear, dose-related deficits as a result of lead exposure on tests of activity, attention and memory, distractibility and adaptability. In... 

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