1. Department of Gastroenterology, Oita San-ai Medical Center, 1213 Oaza Ichi, Oita 870-1151, Japan
2. Department of Gastroenterology, Faculty of Medicine, Oita University, 1-1 Idaigaoka, Hasamacho, Yufu 879-5593, Japan
3. Department of Gastroenterology, Nankai Medical Center, 7-8 Tokiwanishimachi, Saiki 876-0857, Japan
4. Department of Gastroenterology, Shin Beppu Hospital, 3898 Tsurumi, Beppu 874-8538, Japan
5. Department of Gastroenterology, Oita Medical Center, 2-11-45 Yokota, Oita 870-0263, Japan
6. Department of Gastroenterology, Oita City Medical Association Almeida Memorial Hospital, 1509-2 Miyazaki, Oita 870-1195, Japan
7. Department of Endoscopy, Kishiwada Tokushukai Hospital, 4-27-1 Kamoricho, Kishiwada, Osaka 596-8522, Japan
8. Department of Gastroenterology, Saiseikai Kawaguchi General Hospital, 5-11-5 Nishikawaguchi, Kawaguchi 332-8558, Japan
9. Department of Computational Brain Imaging, ATR Neural Information Analysis Laboratories, 2-2-2 Hikaridai, Seika-cho, Soraku-gun, Kyoto 619-0288, Japan