1. Department of Urology & Biochemistry, Kumamoto University School of Medicine, Honjo, 2-2-1, Kumamoto 860, Japan
2. The Research Institute, Nacalai Tesque, Kyoto, Japan
3. Department of Clinical Pathology, Showa University School of Medicine, Tokyo, Japan
4. Laboratory of Clinical Chemistry, National Cardiovascular Center Hospital, Suita, Japan