1. Department of Medicine and Clinical Science, Okayama University Graduate School of Medicine and Dentistry, 2-5-1 Shikata-cho, Okayama 700-8558, Japan
2. Institute of Nephrology, the First Teaching Hospital, Beijing Medical University, 8 Xi Shi Ku Street, Beijing 100034, People's Republic of China
3. Department of Brain Science, Okayama University Graduate School of Medicine and Dentistry, 2-5-1 Shikata-cho, Okayama 700-8558, Japan