Much of organic chemistry is based on the ability of suitably structured chemicals to bind together through the formation of covalent bonds. Biochemistry is replete with exam ples of enzymatically catalyzed reactions in which normal body constituents can be linked through covalent bonds during the process of intermediary metabolism. The finding that xenobiotic chemicals that enter the body from the environment, are metabolized to highly reactive species, and then covalently react with cellular macromolecules to induce toxic and carcinogenic effects was an observation that spawned the research featured in the Fifth International Symposium on Biological Reactive Intermediates (BRI V). The group of investigators that became fascinated with this process and its signifi cance in terms of human health began their discussions in Turku, Finland (J 975), and continued them at Guildford, England (1980), College Park, Maryland (1985), Tucson, Arizona (1990), and Munich, Germany (1995). Among the results were a series of reports listed below, as well as the book for which this serves as the Preface. * Jollow, DJ., Kocsis, J.J., Snyder, R. and Vainio, H. (eds), Biological Reactive Intermediates: Formation, Toxicity and Inactivation, Plenum Press, NY, 1975. * Snyder, R., Park, D.V., Kocsis, J.J., Jollow, D.V., Gibson, G.G. and Witmer, C.M. (eds), Biological Reactive Intermediates II: Chemical Mechanisms and Biological Effects, Plenum Press, N.Y., 1982.

Historically we have separated the disciplines of Chemistry and Biochemistry by recognizing that the distinguishing characteristic of Biochemistry is the catalysis of reactions by enzymes. Enzymes permit metabolic reactions which would otherwise require extremes of temperature, pressure or pH, often associated with Chemistry, to proceed under ambient conditions of the body. Under some conditions chemical reactions occur in vivo in which products of enzymatic reactions proceed to undergo further reactions non- enzymatically with cellular macromolecules. The results can often be seen as toxic or carcinogenic responses. The chemicals that initiate these reactions are termed "biological reactive intermediates. " The International Symposia on Biological Reactive Intermediates (BRI) began in 1975 at the University of Turku, Finland and have since convened at the University of Surrey, Guildford, The United Kingdom (1980), the University of Maryland, College Park, Maryland (1985), the University of Arizona, Tucson, Arizona (1990), the GSF Forschungszentrum and Technical University of Munich (1995) and, most recently, at the Universite Rene Descartes, Paris, France (2000). The Symposium was organized by an International Planning Committee co-chaired by P. Dansette (Paris, France) and TJ. Monks (Austin, Texas). The committee included: P. H. Beaune (Paris, France), M. De\aforge (Saclay, France), G. P. Gervasi (Pisa, Italy), G. G. Gibson (Guildford, UK), H. Greim (Munich, Germany), DJ. Jollow (Charleston, South Carolina), P. Moldeus (Sodertalje, Sweden), I. G. Sipes (Tucson, Arizona), R. Snyder PJ. van Bladderen (Zeist, The Netherlands). They were (Piscataway, New Jersey), and assisted by an International Scientific Program Advisory Committee which included: TJ.

Much of organic chemistry is based on the ability of suitably structured chemicals to bind together through the formation of covalent bonds. Biochemistry is replete with exam ples of enzymatically catalyzed reactions in which normal body constituents can be linked through covalent bonds during the process of intermediary metabolism. The finding that xenobiotic chemicals that enter the body from the environment, are metabolized to highly reactive species, and then covalently react with cellular macromolecules to induce toxic and carcinogenic effects was an observation that spawned the research featured in the Fifth International Symposium on Biological Reactive Intermediates (BRI V). The group of investigators that became fascinated with this process and its signifi cance in terms of human health began their discussions in Turku, Finland (J 975), and continued them at Guildford, England (1980), College Park, Maryland (1985), Tucson, Arizona (1990), and Munich, Germany (1995). Among the results were a series of reports listed below, as well as the book for which this serves as the Preface. * Jollow, DJ., Kocsis, J.J., Snyder, R. and Vainio, H. (eds), Biological Reactive Intermediates: Formation, Toxicity and Inactivation, Plenum Press, NY, 1975. * Snyder, R., Park, D.V., Kocsis, J.J., Jollow, D.V., Gibson, G.G. and Witmer, C.M. (eds), Biological Reactive Intermediates II: Chemical Mechanisms and Biological Effects, Plenum Press, N.Y., 1982.

Historically we have separated the disciplines of Chemistry and Biochemistry by recognizing that the distinguishing characteristic of Biochemistry is the catalysis of reactions by enzymes. Enzymes permit metabolic reactions which would otherwise require extremes of temperature, pressure or pH, often associated with Chemistry, to proceed under ambient conditions of the body. Under some conditions chemical reactions occur in vivo in which products of enzymatic reactions proceed to undergo further reactions non- enzymatically with cellular macromolecules. The results can often be seen as toxic or carcinogenic responses. The chemicals that initiate these reactions are termed "biological reactive intermediates. " The International Symposia on Biological Reactive Intermediates (BRI) began in 1975 at the University of Turku, Finland and have since convened at the University of Surrey, Guildford, The United Kingdom (1980), the University of Maryland, College Park, Maryland (1985), the University of Arizona, Tucson, Arizona (1990), the GSF Forschungszentrum and Technical University of Munich (1995) and, most recently, at the Universite Rene Descartes, Paris, France (2000). The Symposium was organized by an International Planning Committee co-chaired by P. Dansette (Paris, France) and TJ. Monks (Austin, Texas). The committee included: P. H. Beaune (Paris, France), M. De\aforge (Saclay, France), G. P. Gervasi (Pisa, Italy), G. G. Gibson (Guildford, UK), H. Greim (Munich, Germany), DJ. Jollow (Charleston, South Carolina), P. Moldeus (Sodertalje, Sweden), I. G. Sipes (Tucson, Arizona), R. Snyder PJ. van Bladderen (Zeist, The Netherlands). They were (Piscataway, New Jersey), and assisted by an International Scientific Program Advisory Committee which included: TJ.

This supplement contains the papers submitted at EUROTOX 88, the joint Congress of the European Society of Toxicology and the Federation of the European Societies of Toxicology. The theme was one of monitoring and examining the effects of toxic substances in the biological response at the subcellular level. Mechanisms of metal carcinogenicity are discussed as well as the biomonitoring of chemical exposure. Reports are provided on the role of individual differences in man and the effect of risk assessment. Papers appear dealing with the genetic control of drug metabolizing enzymes. The role of metabolism in organic specific toxicity is discussed. Information is included on the toxicological impact of chemicals interfering with the endocrine system as well as on the effects of toxicants on the immune system. Presentations deal with the current status of risk assessment in environmental toxicology.

Was man A1/4ber Giftstoffe, deren Wirkung und Bewertung wissen muss: Zwei erfahrene Toxikologen erklAren allgemeinverstAndlich, wann ein Stoff zum Schadstoff wird. Der Schwerpunkt liegt dabei auf den allgemeinen Grundlagen einer toxikologischen Untersuchung und Bewertung von Schadstoffen, sowie den daraus abgleiteten Handlungsempfehlungen. Anhand bekannter Beispiele aus den letzten Jahren, u. a. des Unkrautvernichters Glyphosat oder des Insektizids Fipronil, die beide in Nahrungsmitteln nachgewiesen wurden, wird erlAutert, wie konkrete GesundheitsgefAhrdungen anhand toxikologischer Daten und Verfahren ermittelt und welche MaA nahmen zum Schutz der Gesundheit daraus abgeleitet werden. Die Anwendung der toxikologischen Verfahren fA1/4r die Bewertung von Gesundheitsrisiken wird anhand von Beispielen aus dem Alltag anschaulich dargestellt, von Lebensmitteln A1/4ber Kosmetika bis hin zu Arzneimitteln und Alltagsprodukten. Ein kompakter, aber fundierter Einstieg in ein wichtiges und oft kontrovers diskutiertes Thema - fA1/4r alle, die Toxine und deren Wirkungen auf Mensch und Umwelt verstehen wollen.

This volume provides documentations for the established MAK values (maximum workplace concentrations) of selected occupational toxicants, including an authoritative review of the available toxicological studies and data. For each substance, the toxic effects, mechanisms and modes of action, toxicogenetics and metabolism, effects in man and animals are described. In addition, the carcinogenic, germ-cell mutagenic, sensitizing or skin-resorptive effects as well as their toxicity to the reproductive system are evaluated, plus basic physico-chemical data are provided. The documentations are thus not only essential for the application of MAK values but also provide a concise toxicological overview for each substance.