1. Department of Medicine, Division of Gastroenterology, Jichi Medical University, Tochigi, Japan
2. Department of Gastroenterology, Mongolian National University of Medical Sciences, Ulaanbaatar, Mongolia
3. Department of Pediatrics, Mongolian National University of Medical Sciences, Ulaanbaatar, Mongolia
4. Shinozaki Medical Clinic, Utsunomiya, Japan
5. Department of Surgery, Jichi Medical University, Tochigi, Japan