1. Division of Gastroenterology and Hepatology, Department of Internal Medicine, Toho University Ohashi Medical Center, Tokyo 153-8515, Japan
2. Department of Gastroenterology and Hepatology, Kyorin University School of Medicine, Tokyo 181-8611, Japan
3. Department of Gastroenterology, Graduate School of Medicine, Juntendo University, Tokyo 113-8421, Japan
4. Department of Gastroenterology, Graduate School of Medicine, The University of Tokyo, Tokyo 113-0033, Japan
5. Department of Gastroenterology and Hepatology, Tokyo Medical University Hachioji Medical Center, Tokyo 193-0998, Japan
6. Division of Gastroenterology, Department of Medicine, Showa University School of Medicine, Tokyo 142-8555, Japan
7. Division of Gastroenterology and Hepatology, Department of Internal Medicine, Keio University School of Medicine, Tokyo 160-8582, Japan
8. Department of Gastroenterology and Hepatology, St. Marianna University School of Medicine, Kawasaki 216-8511, Japan
9. Department of Endoscopy and Endoscopic Surgery, The University of Tokyo Hospital, Tokyo 113-8655, Japan