Fig 4. Cell doubling and AChE activity.

Effect of cell doubling numbers on cell surface marker expression (CD56, CD90, SSEA-4) (A). AChE activity measured 6 days after differentiation of cells harvested after a total culture time of 6 days with differing numbers of medium changes during the cultivation period leading to different growth kinetics was correlated with the relative number of population doublings over 6 days of culture. Pearson linear regression analysis led to a p-value of p = 0.0216, a correlation coefficient of r = 0.9314 and a coefficient of determination of r² = 0.8664. 95% confidence intervals are shown as dotted line (B). Data presented as mean±SEM of three individual experiments.