1. University of the Ryukyus, Faculty ofMedicine, Department of Health Sciences, 207 Uehara,Nishihara, Okinawa 903-0215, Japan
2. Okinawa Prefectural Institute of Health and Environment, 2085 Aza-Ozato, Ozato, Nanjo, Okinawa 901-1202, Japan
3. National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo 158-8501, Japan
4. Nagasaki University, Graduate School of Biomedical Sciences, 1-12-4 Sakamoto, Nagasaki, Nagasaki 852-8523, Japan
5. Central Research Laboratory Nippon Suisan Kaisha, Ltd, 559-6 Kitanomachi, Hachiouji-shi, Tokyo 192-0606, Japan
6. Japan Food Research Laboratories, 6-11-10 Nagayama, Tama-shi, Tokyo 206-0025; National Research Institute of Fisheries Science, 2-12-4 Fukuura, Kanazawa-ku, Yokohama, Kanagawa 236-8648, Japan