1. Department of Veterinary Medical Chemistry, Swedish University of Agricultural Sciences, Uppsala Biomedical Center, Box 575, S-751 23 Uppsala, Sweden,
2. Department of Clinical Chemistry, University of Lund, University Hospital, S-221 85 Lund, Sweden,
3. joint Diseases Laboratory, Shriners Hospital for Crippled Children and the Department of Surgery, McGill University, Montreal, Quebec, Canada H3G 1A6