1. Department of Gastroenterology, National Hospital Organization Tokyo Medical Center
2. Department of Gastroenterology and Hepatology, International University of Health and Welfare, Narita Hospital
3. Endoscopy Division, National Cancer Center Hospital
4. Gastroenterology, Saitama Medical Center
5. Division of Gastroenterology and Hepatology, Department of Internal Medicine, Tokai University School of Medicine
6. Gastroenterology, Clinic of a Wind, Komazawa