1. Department of General Internal Medicine, Okayama City Hospital, 3-20-1, Omote-cho, Kitanagase, Okayama-city, Okayama 700-0962, Japan
2. Department of General Internal Medicine, Mitoyo General Hospital, 708, Himehama, Toyohama-cho, Kanonji-city, Kagawa 769-1695, Japan