Immunocytochemical analysis of phenotype of CD34⁺ cells after injury. Immunocytochemical analysis of CD34⁺ cells isolated on day 2. All cells stained with DAPI (blue). Original images taken at 100× magnification—some of the images chosen have been electronically magnified (1-3×) in the process of selecting appropriate fields. (A) Cells stained for CD31 (red) and Flk-1 (green). Dual exposure image is on the right and illustrates that all CD31-expressing cells coexpress Flk-1 (yellow), but not all Flk-1⁺ cells express CD31 (green). (B) Cells stained for CD31 (red) and TF (green). Dual exposure image is on the right and shows that all CD31-expressing cells stain for TF (yellow). (C) Cells stained for α-SMA (red) and Flk-1 (green). Dual exposure image is on right of the panel, and illustrates that in this field, none of the α-SMA–expressing cells stain for Flk-1. (D) Cells stained for α-SMA (red) and TF (green). Dual exposure image is on right of the panel, and shows that the single α-SMA–expressing cell in this field stains for TF (yellow). (E) Cells stained for α-SMA (red) and CD31 (green). Dual exposure image is on right of the panel, and shows a single cell in this field that stains for both markers (yellow). Representative of 2 independent assessments.