1. Graduate School of Fisheries Sciences, Hokkaido University, Minato 3-1-1, Hakodate, Hokkaido 041-8611, Japan; Watanabe-Kazuhiko Pediatric Clinic, 1-13, Hondori 1- Minami, Shiroishi-Ku, Sapporo, Hokkaido 003-0026, Japan; and Faculty of Food Science and Biotechnology, Pukyong National University, 599-1, Deayeon 3- Dong Nam- Gu, Pusan 608-737, Korea