Author's Organization：
Research & Development Division, Nippon Hoechst Marion Roussel Ltd. Japanese Pharmaceutical Manufacturers' Association
Yokohama Research Center, Research and Development Division, Mitsubishi Chemical Corporation, Japanese Pharmaceutical Manufacturers' Association
Preclinical R & D Department, SmithKline Beecham Seiyaku K.K., Japanese Pharmaceutical Manufacturers' Association
Institute for Life Science Research, Asahi Chemical Industry Co., Ltd., Japanese Pharmaceutical Manufacturers' Association