1. Department of Veterinary Pathology, School of Veterinary Medicine, Kitasato University, Aomori 034–8628, Japan
2. Laboratory of Veterinary Clinical Pathology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo 113–8657, Japan
3. Veterinary Pharmacology, School of Veterinary Medicine, Kitasato University, Aomori 034–8628, Japan