1. Hokkaido Institute of Environmental Sciences, Kita-19, Nishi-12, Kita-ku, Sapporo, 060-0819, Japan, Hokkaido Institute of Public Health, Kita-19, Nishi-12, Kita-ku, Sapporo 060-0819, Japan, and Diagnostic Division, Otsuka Pharmaceutical Company, Ltd., Tokushima 771-0195, Japan