1. Shinozaki Medical Clinic, Utsunomiya, Tochigi 321‑3223, Japan
2. Department of Medicine, Division of Gastroenterology, Jichi Medical University, Shimotsuke, Tochigi 329‑0498, Japan
3. Department of Surgery, Jichi Medical University, Shimotsuke, Tochigi 329‑0498, Japan