1. First Department of Medicine, Hamamatsu University School of Medicine, Higashi-ku, Hamamatsu 431-3192, Japan
2. Department of Gastroenterology, College of Medicine, Dong-A University, Busan 602-715, Republic of Korea
3. Department of Gastroenterology, Seirei General Hospital, Naka-ku, Hamamatsu 430-8558, Japan
4. Department of Endoscopic and Photodynamic Medicine, Hamamatsu University School of Medicine, Higashi-ku, Hamamatsu 431-3192, Japan
5. Center for Clinical Research, Hamamatsu University School of Medicine, Higashi-ku, Hamamatsu 431-3192, Japan