Flow cytometry analysis on DiI⁺ isolated cells of YS after 1 hour of culture. The tissues of the inoculated embryos after 1 hour of culture were incubated in a dispased solution and examined by flow cytometry. (A) After the adequate cell population was selected by R1 (left panel), both dead cells incorporating TO-PRO-1 and the Mac-1⁺ cells were eliminated by R2 (middle panel), and the cells expressing DiI were observed (right panel). DiI⁺ cells selected by R3 were analyzed (B-E). (B) Isotype control. (C-E) Expression of CD45 (C), CD31 (PECAM) (D), and CD34 (E) by DiI⁺ cells.