1. Division of Pathology, Biosafety Research Center, Foods, Drugs and Pesticides, 582-2, Arahama Shioshinden, Fukude-cho, Iwata-gun, Shizuoka-ken, 437-12, Japan
2. The 1st Department of Veterinary Pathology, Azabu University, 1-17-71, Fuchinobe, Sagamihara-shi, Kanagawa-ken, 424-01, Japan