1. Department of Public Health, Graduate School of Medicine, Hokkaido University, Sapporo, Japan, Department of Oral Pathology, Meikai University School of Dentistry, Saitama, Japan, Department of Environmental Protection, Hokkaido Research Institute of Environmental Sciences, Sapporo, Japan, Hiyoshi Corporation, Shiga, Japan, Department of Pathology, Faculty of Medicine, University of Tokyo, Tokyo, Japan, and TARA Center, University of Tsukuba, Tsukuba, Japan