Gene expression. Human fetal liver cells were analyzed after 4 days of culture in bioreactors configured to provide perfusion (dark bars) and diffusion (patterned bars) conditions during culture. Gene expression was normalized to day 0 freshly isolated human fetal liver cells, with beta-actin as a housekeeping gene. Harvested cells from the two conditions were analyzed for gene expression of (A) endothelial related genes: endothelial nitric oxide synthase (eNOS), CD144, CD309, CD140b, neutral sphingomyelinase (NSM), CD31, and von Willebrand factor (vWF), (B) hematopoietic genes: CD34, CD45, and CD235a, and (C) liver-related genes: CYP3A4 and CK19. Data are given as means±SEM for five biological repeats (*p<0.05).