Endothelial markers expressed by lineage-negative cells from catalase-treated LTBMCs. (A) Two-dimensional histograms (cytograms) of CD31 (y-axis) plotted against CD45 (x-axis) after 3 weeks of culture with and without catalase. Sca-1⁺ cells are shown in black and Sca-1^- cells are shown in gray. (B) Two-dimensional histograms (cytograms) showing the expression of (i) CD31 versus CD45, (ii) CD31 versus LN (lineage negative), and (iii) c-Kit versus LN by nonadherent cells collected after 3 weeks of culture in the presence of catalase.