[1] KAROLINSKA INST, DEPT PHARMACOL, S-10401 STOCKHOLM 60, SWEDEN
[2] KAROLINSKA INST, DEPT HISTOL, S-10401 STOCKHOLM 60, SWEDEN
[3] BISPEBJERG HOSP, DEPT CLIN CHEM, DK-2400 Copenhagen, DENMARK
[4] UNIV ZURICH, DEPT ORTHOPED SURG & MED, CH-8006 ZURICH, SWITZERLAND