1. Gastrointestinal Endoscopy, NTT Medical Center Tokyo, Tokyo, Japan
2. Gastroenterology, Kyorin University Hospital, Tokyo, Japan, Mitaka, Japan
3. Gastroenterology, Yokohama Sakae Kyosai Hospital, Kanagawa, Japan, Yokohama, Japan
4. Gastroenterology, Omori Red Cross Hospital, Tokyo, Japan, Ota-Ku, Japan