1. Department of Medical Chemistry, Faculty of Medicine, Vrije Universiteit, P.O. Box 7161, 1007 MC Amsterdam, The Netherland
2. Division of Liver and Pancreatic Diseases, University Hospital Gasthuisberg, 3000 Leuven, Belgium
3. Dipartimento di Biochimica e Biotecnologie Mediche, Il Facoltà di Medicina e Chirugia, Via Pansini 5,Università di Napoli, I-80131 Naples, Italy
4. Unité de Biochimie, Département Universitaire de Psychiatrie Adulte, Hopital de Cery, CH-1008 Prilly-Lausanne, Switzerland