1. Department of Diabetes and Metabolic Medicine, Center Hospital, National Center for Global Health and Medicine, Tokyo 162-8655, Japan
2. Department of Surgery, Center Hospital, National Center for Global Health and Medicine, Tokyo 162-8655, Japan
3. Pathology Division of Clinical Laboratory, Center Hospital, National Center for Global Health and Medicine, Tokyo 162-8655, Japan
4. Division of Nuclear Medicine, Center Hospital, National Center for Global Health and Medicine, Tokyo 162-8655, Japan
5. Department of Diabetes Research, Diabetes Research Center, National Center for Global Health and Medicine, Tokyo 162-8655, Japan