1. Department of Gastroenterology and Hepatology, Gunma University Hospital, Maebashi, Japan
2. Department of Gastroenterology, Osaka University Graduate School of Medicine, Osaka, Japan
3. Department of Gastroenterology, Nippon Medical School, Graduate School of Medicine, Tokyo, Japan
4. Department of Medical Education, Yokohama City University School of Medicine, Yokohama, Japan
5. Office of Postgraduate Medical Education, Yokohama City University Hospital, Yokohama, Japan
6. Kurokawa general hospital, Miyagi, Japan