1. Department of Gastroenterology and Hepatology, Tokyo Medical University, Japan
2. Department of Gastroenterology, Yuri Kumiai General Hospital, Japan
3. Yamada Diabetes Gastroenterology Clinic, Japan
4. Department of Neurological Surgery, Yuri Kumiai General Hospital, Japan
5. Department of Surgery, Yuri Kumiai General Hospital, Japan
6. Division of Gastroenterology and Hepatology, Department of Medicine, Nihon University School of Medicine, Japan