[1] Inst Environm & Occupat Toxicol, Casella Postale 108, CH-6780 Airolo, Switzerland
[2] Univ Munich, Walther Straub Inst Pharmakol & Toxikol, Munich, Germany
[3] Finnish Inst Occupat Hlth, Helsinki, Finland
[4] Newcastle Univ, Sch Med, Dept Environm & Occupat Med, Newcastle Upon Tyne, Tyne & Wear, England
[5] Chinese Acad Prevent Med, Inst Occupat Med, Beijing, Peoples R China