1. Department of Internal Medicine, Okayama Saiseikai General Hospital, Japan
2. Department of Gastroenterology and Hepatology, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Japan
3. Department of General Medicine, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Japan
4. Department of Anatomic Pathology, Okayama Saiseikai General Hospital, Japan