1. Department of Gastroenterology, Okayama University Hospital, Okayama, Japan
2. Department of Gastroenterology, Fukuyama Medical Center, Hiroshima, Japan
3. Department of Internal Medicine, Tsuyama Central Hospital, Okayama, Japan
4. Department of Endoscopy, Hiroshima City Hiroshima Citizens Hospital, Hiroshima, Japan
5. Department of Gastroenterology and Hepatology, Kurashiki Central Hospital, Okayama, Japan
6. Department of Internal Medicine, Himeji Red Cross Hospital, Hyogo, Japan
7. Department of Gastroenterology, Okayama City Hospital, Okayama, Japan
8. Department of Pathology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan
9. Department of Practical Gastrointestinal Endoscopy, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan
10. Department of Internal Medicine, Akaiwa Medical Association Hospital, Okayama, Japan