1. Department of Internal Medicine and GastroenterologyTokyo Women's Medical University Yachiyo Medical Center Chiba Japan
2. Department of Internal Medicine, Institute of GastroenterologyTokyo Women's Medical University Tokyo Japan
3. Department of Surgery, Institute of GastroenterologyTokyo Women's Medical University Tokyo Japan
4. Department of SurgeryTokyo Women's Medical University Yachiyo Medical Center Chiba Japan