1. Department of Diabetes, Endocrine and Metabolism, Toho University Graduate School of Medicine, Tokyo, Japan
2. Center of Diabetes, Endocrinology, and Metabolism, Sakura Hospital, Toho University, Chiba, Japan
3. Department of Clinical Cell Biology & Medicine, Graduate School of Medicine, Chiba University, Chiba, Japan
4. Department of Medicine, Chiba Aoba Municipal Hospital, Chiba, Japan