1. Evaluation Technology Department 1, R&D Group, Olympus Corporation, Hachioji, Tokyo 192-8512, Japan
2. Laboratory of Veterinary Pathology, Division of Animal Life Science, Institute of Agriculture, Tokyo University of Agriculture and Technology, Fuchu, Tokyo 183-8509, Japan
3. Institute of Global Innovation Research, Tokyo University of Agriculture and Technology, Fuchu, Tokyo 183-8509, Japan