Fig. 2.

Primary culture development is characterized by a progressive shortening and stabilization of the passage time. (A) The number of days to confluence at each passage number is shown for the seven cultures R1–R7. Cultures were diluted 1:2 from P1 to P13 and 1:4 after P14 (data were normalized for comparison with the 1:2 dilutions). (B) Morphology of cultured cells at P0, P4, and P12. Images shown are representative of all the lines.