1. Department of Veterinary Pathology, Faculty of Agriculture, Gifu University, Gifu, Japan
2. Toxicology Laboratory, Sankyo Co., Fukuroi, Shizuoka, Japan
3. Department of Veterinary Pathology, Faculty of Agriculture, The University of Tokyo, Tokyo, Japan
4. Department of Pathobiology, Nihon University School of Veterinary Medicine, Fujisawa, Japan