1. Laboratory of Veterinary Physiology, School of Veterinary Medicine, Kitasato University, Aomori 034-8628, Japan
2. Clinic for Small Domestic Animals and Radiology, Faculty of Veterinary Medicine, Mahanakorn University of Technology, Bangkok 10530, Thailand
3. Laboratory of Veterinary Physiology, School of Veterinary Medicine, Okayama University of Science, Ehime 794-8555, Japan