1. National Institute for Minamata Disease, Minamatu City, Kumamoto, Japan, .
2. National Institute for Minamata Disease, Minamatu City, Kumamoto, Japan
3. Department of Radiology, Kumamoto University School of Medicine, Kumamoto, Japan
4. Department of Pathology, Toho University School of Medicine, Tokyo, Japan
5. Department of Surgical Pathology, Kumamoto University School of Medicine, Kumamoto, Japan
6. Laboratory of Animal Technologists, Animal Care Co Ltd, Tokyo, Japan