1. Department of Clinical Cell Biology and Medicine, Chiba University Graduate School of Medicine, Chiba, 260-8670, Japan
2. Department of Medicine, Division of Diabetes, Metabolism and Endocrinology, Chiba University Hospital, Chiba, 260-8670, Japan
3. School of Medicine, International University of Health and Welfare, Department of Diabetes, Metabolism and Endocrinology, Chiba, 286-8686, Japan
4. Eastern Chiba Medical Center, Chiba, 283-8686, Japan
5. Asahi General Hospital, 1326 I, Chiba, 289-2511, Japan