Colonies of ECFCs were recovered from cell culture, trypsinized, and counted. Cells were plated by limiting dilutions at 1 cell/well in 96-well plates. The number of new colonies was determined at the times indicated. Data represent mean ± SEM of 10 independent experiments.

Emerging colonies were defined as circumscribed monolayers of cobblestone-appearing cells that appeared at the time of microscope examination and that contained at least 20 confluent cells.