1. Graduate School of Medicine and Pharmaceutical Sciences for Research, University of Toyama, 2630 Sugitani, Toyama 930-0194, Japan; Daiichi Yakuhin Kougyo Company Ltd., 15-1 Kusajima, Toyama 930-2201, Japan; and Department of Bioscience and Biotechnology, Konkuk University, 1 Hwaynag-dong, Gwangjin-gu, Seoul 143-701, Korea