1. Laboratoire de Biologie Cellulaire, World Health Collaborating Center for the Development of the Endocrine Pancreas, Université Catholique de Louvain, B-1348 Louvain-La-Neuve, Belgium
2. Lawson Health Research Institute, St. Joseph's Health Care, London, ON and Departments of Medicine, Physiology and Paediatrics, University of Western Ontario, London, ON N6A 4V2, Canada