SA-β-gal-positive cells in the UC-derived primary cell population (A) and in the CCE-derived subpopulations of small- (B) and large-sized (C) cells. Cells were cultured for 6 days after elutriation. Following subculture, the cells were seeded at the density of 6,000 cells/cm2 and cultured for further 48 h in complete medium. A relative high portion of binucleated cells (arrows) were detectable in the subpopulation of the large-sized cells. Student's t-tests were performed for the recognition of the significant differences (marked with asterisks) in comparison to UC-derived primary cell population.