1. From the Department of Molecular and Internal Medicine (Y.O., H.Y., N.K., M.S.), Graduate School of Biomedical Sciences, the Department of Developmental Biology (H.H.), Research Institute for Radiation Biology and Medicine, the Department of Anatomy and Histology (S.K.), Graduate School of Health Sciences, and the Department of Cardiovascular Physiology and Medicine (S.M., N.N.S., M.Y.), Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima, Japan.