1. Department of Biochemistry, Mitsubishi Kagaku Bio-Clinical Laboratories, Inc., Shimura 3-30-1, Itabashi-ku 174, Japan; Department of Forensic Science, School of Allied Health Science, Kitasato University, 1-15-1 Kitasato, Sagamihara City 228, Japan; Department of Laboratory Medicine, School of Medicine, Hamamatsu University, Handa-cho 3600, Hamamatsu 431–31, Japan