Department of Toxicology, University Medical Center Mainz, 55131 Mainz, Germany; Rudolf Buchheim Institute of Pharmacology, Justus Liebig University Giessen, 35392 Giessen, Germany; Division of Food Chemistry and Toxicology, Department of Chemistry, Technical University of Kaiserslautern, 67663 Kaiserslautern, Germany. Rudolf Buchheim Institute of Pharmacology, Justus Liebig University Giessen, 35392 Giessen, Germany. Department of Toxicology, University Medical Center Mainz, 55131 Mainz, Germany. Department of Toxicology, University Medical Center Mainz, 55131 Mainz, Germany; Rudolf Buchheim Institute of Pharmacology, Justus Liebig University Giessen, 35392 Giessen, Germany; Division of Food Chemistry and Toxicology, Department of Chemistry, Technical University of Kaiserslautern, 67663 Kaiserslautern, Germany. Electronic address: fahrer@chemie.uni-kl.de.