Characterization of hUCBSCs. (a) Cells stain positive for fibronectin (brown). (b) Cells stain positive (brown) for CD44. (c) Cells do not stain for CD45. (d) Cells labeled with BrdU. Note. hUCBSCs = human umbilical cord blood stem cells; BrdU = Br5-bromo-2′-deoxyuridine.