The number of Weibel-Palade bodies per HUVEC is less in endothelial cells from preterm infants. This figure is representative of the data in Fig 5. (A) is from a 23-week gestation infant and (B) is from a term infant. Here there are 4 to 5 times as many Weibel-Palade bodies (arrows) in the cytoplasm of the term infant compared with the preterm infant.