1. Division of Digestive Endoscopy, Shiga University of Medical Science, Otsu, Japan
2. Division of Endoscopy, Shizuoka Cancer Center, Sunto-gun, Japan
3. Department of Gastroenterology, Kobe City Medical Center General Hospital, Kobe, Japan
4. Division of Gastroenterology, Shiga University of Medical Science, Otsu, Japan