Microscopic appearance of 10-day cultures. CD34⁺ CB cells were cultured in TGF-β1 plus GM-CSF, TNFα, and SCF supplemented serum-free medium (left) or in identical medium additionally containing FL (center and right) as described in the Materials and Methods. Representative phase contrast microscopic appearance of cells at low power (original magnification × 20 for left and center panels) or high power (original magnification × 40 for right panel) view is shown.