1. Endoscopy Division; National Cancer Center Hospital; Tokyo Japan
2. Department of Gastroenterology; Saku Central Hospital; Nagano Japan
3. Department of Gastroenterology and Hepatology; Nagasaki University Hospital; Nagasaki Japan
4. Department of Gastroenterology and Hepatology; School of Medicine; Iwate Medical University; Morioka Japan
5. Gastroenterological Center; Yokohama City University Medical Center; Yokohama Japan
6. Department of Gastroenterology; Kitasato University School of Medicine; Sagamihara Japan
7. Department of Internal Medicine; Hiroshima City Hospital; Hiroshima Japan
8. The Third Department of Internal Medicine; Kyorin University School of Medicine; Tokyo Japan