1. Gastroenterology, Toyoshima Endoscopy Clinic, Tokyo, Japan
2. Department of Gastroenterology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
3. Department of Gastroenterology and Hepatology, International University of Health and Welfare, Chiba, Japan
4. Department of Gastroenterology, The Fraternity Memorial Hospital, Tokyo, Japan
5. Department of Gastroenterology, Kyoundo Hospital, Tokyo, Japan
6. Department of Gastrointestinal Surgery, JR Tokyo General Hospital, Tokyo, Japan
7. Gastroenterology, Ando Family Clinic, Tokyo, Japan