Institution: | 1. Department of Gastroenterology, Yokohama Municipal Citizen's Hospital, , Kanagawa, Japan;2. Division of Gastroenterology and Hepatology, Department of Internal Medicine, Keio University, , Tokyo, Japan;3. Center for Diagnostic and Therapeutic Endoscopy, School of Medicine, Keio University, , Tokyo, Japan;4. Endoscopy Center, NHO Kurihama Medical and Addiction Center, , Yokosuka, Japan |