1. School of Veterinary Nursing and Technology, Faculty of Veterinary Science, Nippon Veterinary and Life Science University, Tokyo 180-8602, Japan
2. Laboratory of Laboratory Animal Science and Medicine, Department of Disease Control, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo 060-0818, Japan
3. Department of Veterinary Surgery, The University of Tokyo, Bunkyo, Tokyo 113-8657, Japan
4. Department of Veterinary Pathology, Faculty of Veterinary Science, Nippon Veterinary and Life Science University, Tokyo 180-8602, Japan
5. Department of Applied Life Science, Faculty of Food Science, Nippon Veterinary and Life Science University, Tokyo 180-8602, Japan
6. Department of Urology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama 700-8558, Japan