HUBEC culture induces cell division within quiescent ABM CD34⁺CD38⁻ cells.

(A) The dot plot shows the 7-AAD versus Ki-67 FITC profile for steady-state bone marrow CD34⁺CD38⁻ cells, with the majority of the population residing in G₀. (B) CD34⁺CD38⁻ cells were FACS-sorted from 7-day HUBEC cocultures and stained for 7-AAD versus Ki-67 FITC expression, demonstrating that the majority of the CD34⁺CD38⁻ population had entered cell cycle. Cell cycle analysis of CD34⁺ cells was performed by means of the SID method described in “Materials and methods.”