臍帯血由来CD133陽性細胞におけるES関連遺伝子の発現と臍帯由来細胞を用いた幹細胞性の維持 (Embryonic Stem Cell Marker Gene Expression on Cord Blood :CD133 Positive Cells and Maintenance of CD133 Cell Surface Antigen and ES associated markers preserved by Umbilical Cord S t r o m a l C e l l s)