1. Division of Biochemical Toxicology Stockholm Sweden
2. Division of ToxicologyInstitute of Environmental Medicine Stockholm Sweden
3. Division of Biochemistry, Department of Medical Biochemistry and BiophysicsKarolinska Institutet Stockholm Sweden
4. Dept of Anatomy, Institute of Basic Medical SciencesUniversity of Oslo POB 1105 Blindern 0317 Oslo Norway
5. Department of Genetic ToxicologyAstraZeneca R and D Södertälje, Safety Assessment S‐15185 Södertälje Sweden