1. Second Department of Internal Medicine Wakayama Medical University Wakayama Japan
2. Clinical Study Support Center Wakayama Medical University Hospital Wakayama Japan
3. Department of Gastroenterology Graduate School of Medicine Chiba University Chiba Japan
4. Department of Endoscopy and Endoscopic Surgery The University of Tokyo Hospital Tokyo Japan
5. Department of Gastroenterology Graduate School of Medicine The University of Tokyo Tokyo Japan
6. Department of Gastroenterology Kyoto Second Red Cross Hospital Kyoto Japan
7. Department of Gastroenterology Graduate School of Medicine Juntendo University Tokyo Japan