1. Department of General Medicine and Emergency Care, School of Medicine, Toho University, Omori Hospital, Tokyo 143-8541, Japan
2. Department of Hematology, School of Medicine, Toho University, Omori Hospital, Tokyo 143-8541, Japan
3. Division of Gastroenterology and Hepatology, School of Medicine, Toho University, Omori Hospital, Tokyo 143-8541, Japan
4. Department of Internal Medicine, School of Medicine, Toho University, Omori Hospital, Tokyo 143-8541, Japan