1. Department of Gastroenterology and Hepatology, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Japan
2. Department of General Medicine, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Japan
3. Nakamura Clinic, Japan
4. Department of Pathology, Kameda Medical Center, Japan
5. Department of Gastroenterology, Kameda Medical Center, Japan