Figure 2.

Relationship between age and circulating progenitor cell content. Circulating progenitor cells were enumerated in peripheral blood samples drawn prior to surgery. The percentage of mononuclear cells expressing a progenitor cell phenotype (high levels of aldehyde dehydrogenase activity [upper left panel], CD133 expression [upper right panel], CD34 expression [lower left panel], CD133 and CD34 cell surface expression [lower right panel]) is plotted vs patient age, and the Pearson correlation coefficient and p value for correlation shown.