1. Division of Cardiovascular Medicine, Department of Internal Medicine, University of California, Davis, CA95616, USA.
2. Department of Comparative Pathophysiology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-8657, Japan
3. Department of Veterinary Surgery, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-8657, Japan