1. Department of Cardiovascular Medicine, Faculty of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama 700-8558, Japan
2. Department of Medical Technology, Graduate School of Health Sciences, Okayama University, Okayama 700-8558, Japan
3. Department of Immunology, Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama University, Okayama 700-8558, Japan