1. Division of Pathology, National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo 158-8501, Japan
2. Department of Biological Safety Research, Japan Food Research Laboratories, 2-3 Bunkyo, Chitose-shi, Hokkaido 066-0052, Japan
3. Chemical Management Center, National Institute of Technology and Evaluation, 2-24-9 Nishihara, Shibuya-ku, Tokyo 151-0066, Japan