1. Division of Endocrinology, Metabolism, and Nephrology, Department of Internal Medicine, Keio University School of Medicine, Shinjuku-ku, Tokyo, Japan
2. Apheresis and Dialysis Center, Keio University School of Medicine, Shinjuku-ku, Tokyo, Japan
3. Department of Nephrology, International University of Health and Welfare School of Medicine, Narita, Chiba, Japan
4. Keio University Health Center, Yokohama-shi, Kanagawa, Japan