1. Department of Gastroenterology and Hepatology, Graduate School of Biomedical Sciences, Nagasaki University, Sakamoto 1-7-1, Nagasaki 852-8501, Japan
2. Department of Gastroenterology and Hepatology, Sasebo City General Hospital, Hirase-machi 9-3, Sasebo 857-8511, Japan
3. Department of Gastroenterology and Hepatology, Nagasaki Municipal Hospital, Shinchi-machi 6-39, Nagasaki 850-8555, Japan
4. Department of Gastroenterology and Hepatology, Japanese Red Cross Nagasaki Genbaku Hospital, Mori-machi 3-15, Nagasaki 852-8511, Japan
5. Department of Gastroenterology and Hepatology, Oita Prefectural Hospital, Bunyo 467, Oita 870-8511, Japan
6. Digestive Organ Center, Japan Labour and Welfare Organization, Nagasaki Labour Welfare Hospital, Setogoe 2-12-5, Sasebo 857-0134, Japan
7. Department of Gastroenterology and Hepatology, Sasebo Chuo Hospital, Yamato-machi 15, Sasebo 857-1195, Japan
8. Department of Internal Medicine, Goto Central Hospital, Nagasaki Prefectural, Yoshikugichou 205, Goto 853-0031, Japan
9. Department of Internal Medicine, National Hospital Organization Saga National Hospital, Hinode 1-20-1, Saga 849-8577, Japan
10. Department of Internal Medicine, Kouseikai Hospital, Hayama1-3-12, Nagasaki 852-8053, Japan
11. Department of Gastroenterology and Hepatology, Medical Inc. Kosei-kai Nijigaoka Hospital, Nijigaoka-machi 1-1, Nagasaki 852-8055, Japan
12. Department of Internal Medicine, Caritas Clinic, Nishiizuru-machi 65-7, Nagasaki 851-2322, Japan
13. Clinical Research Center, National Hospital Organization Nagasaki Medical Center, Kubara 2-1001-1, Omura, Nagasaki 856-8562, Japan