1. Department of Surgery Hitachi Ltd. Hitachinaka General Hospital Hitachinaka Ibaraki Japan
2. Hitachinaka Medical Education and Research Center University of Tsukuba Hospital Hitachinaka Ibaraki Japan
3. Department of Hematology Hitachi Ltd. Hitachinaka General Hospital Hitachinaka Ibaraki Japan
4. Department of Neurology Hitachi Ltd. Hitachinaka General Hospital Hitachinaka Ibaraki Japan
5. Department of Clinical Pathology Hitachi Ltd. Hitachinaka General Hospital Hitachinaka Ibaraki Japan