1. Department of Medicine, Brigham and Women's Hospital and Joslin Diabetes Center, Harvard Medical School, One Joslin Place, Boston, Massachusetts 02215
2. Department of Surgery, St. Mary's Hospital, Praed Street, London W2 INY, England
3. Department of Surgery and Laboratory for Surgical Metabolism and Nutrition, Brigham and Women's Hospital and Harvard Medical School, 75 Francis Street, Boston, Massachusetts 02115