1. Department of Digestive Endoscopy, Tokyo Women’s Medical University Hospital, 8-1, Kawada-Chou, Shinjuku-Ku, Tokyo 162-8666, Japan
2. Institute of Gastroenterology, Tokyo Women’s Medical University Hospital, 8-1, Kawada-Chou, Shinjuku-Ku, Tokyo 162-8666, Japan
3. Division of Gastroenterology and Nephrology, Department of Multidisciplinary Internal Medicine, Faculty of Medicine, Tottori University, 36-1, Nishi-Chou, Yonago 683-8504, Japan