1. Division of Hematology, Department of Internal Medicine, Imai Hospital, Tanaka-cho 100, Ashikaga, Tochigi 326-0822, Japan
2. Department of Orthopedics, Imai Hospital, Tanaka-cho 100, Ashikaga, Tochigi 326-0822, Japan
3. Department of Surgery, Imai Hospital, Tanaka-cho 100, Ashikaga, Tochigi 326-0822, Japan
4. Department of Anatomic and Diagnostic Pathology, School of Medicine, Dokkyo Medical University, Mibu-machi, Shimotsuga-gun, Tochigi 321-0293, Japan