Fig. 2.

a Doubling times observed in the different cell lines grown in the presence of FBS or PL 16, 17 and 18. Results are presented as the means ± standard deviations (SD) obtained from triplicates observed with FBS or PL 16, 17 and 18 for 6 passages. Thus, for PL cultures the means and SD of nine observations are shown. *Statistically significant differences between the two values (Student’s t test, p < 0.05). b Representative evaluation of cell cycle analysis of various cell lines carried out in the presence of FBS and PL 17. The average values obtained in a triplicate analysis are presented for both FBS and PL 17