1. Rational Drug Design Laboratories, 4-1-1, Misato, Matsukawa-machi, Fukushima 960-1242, Japan, Sanwa Kagaku Kenkyusyo Company, Ltd., 363, Shiosaki, Hokusei-cho, Inabe-gun, Mie 511-0406, Japan, and Maruwa Food Industry Company, Ltd., 170, Tsutsuji-cho, Yamatokoriyama, Nara 639-1123, Japan