Promise of tomorrow

The topics discussed in this conference represent great scientific opportunity that we will exploit in the future. The objectives of the research programs at NIEHS have been to understand how chemicals interact with living material, cell metabolism, function, and structure. If these mechanisms are understood, it is easier to make judgments about potential health effects and to suggest ways to ameliorate these effects. As Manny Farber emphasized (1), "We must understand the process." This conference shows how the new biology dealing with cell growth and differentiation, regulation (inter-cellular communications, etc.) is being applied to specific organ systems: CNS, reproduction and development, genetic toxicology, and carcinogenesis. Much of the new biology is common to all cells and it is hoped that as we achieve greater understanding, we will be able to understand the role of chemicals in the etiology of many specific disease processes. Although we are aware of many specific risk factors, the etiology of most chronic diseases remains unknown. Advances in basic science should permit us to determine better the role that chemicals play in these common diseases. Environmental factors have some role in many diseases, even those commonly thought of a genetic disease. If you think about it, environment has a major role in such straightforward genetic diseases as phen-ylketonuria (PKU). It is really the susceptibility to PKU that is inherited; the disease is due to toxicity of the excessive phenylalanine that is not metabolized. A child who is homozygous for PKU (that is, one who is deficient in phenylalanine hydroxylase and thus unable to hy-droxylate phenylalanine) is normal in utero because the environment provided by the mother is a safe environment ; after birth, that child still has the disease but only shows the mental retardation when exposed to an uncontrolled environment containing phenylalanine that cannot be metabolized by the normal pathways. If it is possible to remove phenylalanine from the diet (alter the environment), the child is normal. This may be a rather extreme view of the role of environment in disease and not what is ordinarily though of, but I want to make the point that most disease is, indeed, the result of some interaction between the environment and the constitution of the individual. To carry the relationship between genetics and environment one step further to the realm of a common quasi genetic/environmental disease, diabetes mellitus, there are two types of diabetes, insulin-dependent and noninsulin-dependent …