[1] UNIV BASEL, CARDIOL & INTERNAL MED, CH-4051 BASEL, SWITZERLAND
[2] UNIV ROTTERDAM, DEPT MED, ROTTERDAM, NETHERLANDS
[3] UNIV MELBOURNE, DEPT MED, HEILDELBERG, VIC, AUSTRALIA
[4] UNIV FREIBURG, PHYSIOL, D-7800 FREIBURG, GERMANY
[5] ALBERT EINSTEIN HOSP, COLL MED, BRONX, NY 10461 USA
[6] UNIV MILAN, MED, I-20122 MILAN, ITALY