1. Laboratory of Toxicology, School of Veterinary Medicine, Kitasato University, Towada, Aomori 034–8628, Japan
2. Laboratory of Veterinary Public Health, School of Veterinary Medicine, Kitasato University, Towada, Aomori 034–8628, Japan
3. Laboratory of Veterinary Pharmacology, Nippon Veterinary and Life Science University, Musashino, Tokyo 180–8602, Japan