[1] Med Univ Vienna, Vienna, Austria
[2] McMaster Univ, Hamilton, ON L8S 4L8, Canada
[3] UCSD, La Jolla, CA USA
[4] Univ Klinikum Wurzburg, Wurzburg, Germany
[5] Univ Udine, I-33100 Udine, Italy
[6] Washington Sch Med, St Louis, MO USA
[7] Med Univ Vienna, Vienna, Austria
[8] Roche Prod Ltd, Welwyn Garden City AL7 3AY, Herts, England