1. Division of Gastroenterology, Department of Medicine, Kurume University School of Medicine, Kurume 830-0011, Japan
2. Iwamoto Internal Medical Clinic, Kitakyusyu 802-0832, Japan
3. Clinical Research Center, Yokokura Hospital, Miyama 839-0295, Japan
4. Department of Gastroenterology and Hepatology, Yanagawa Hospital, Yanagawa 832-0077, Japan
5. Department of Gastroenterology and Hepatology, Omuta City Hospital, Omuta 836-8567, Japan