First Department of Pathology and First Department of Surgery, Kansai Medical University, Moriguchi City, Osaka 570, Japan; Novartis Pharma K.K., Takarazuka City, Hyogo 665, Japan; Otsuka Pharmaceutical, Inc., Tokushima 771–01, Japan; Department of Pediatrics, All Children’s Hospital, University of South Florida, St. Petersburg, FL 33701 (At 1998-06-09)