Semiquantiative RT-PCR analysis of perlecan mRNA expression in antithrombin-treated HUVECs. HUVECs were cultured with or without 10 μg/mL of the different antithrombin forms in the presence and absence of 10 ng/mL bFGF as indicated for 72 hours. Total mRNA was isolated, and the content of perlecan mRNA relative to β-actin mRNA was analyzed by semiquantitative RT-PCR. The inset shows the relative intensities of 500 bp perlecan and 336 bp β-actin cDNA fragments amplified from reverse-transcribed mRNA with specific primers under the different experimental conditions, as described in “Materials and methods.” Band intensities from the representative experiment shown were quantified and are presented as the ratio of perlecan to β-actin bands in the bar graph. Similar results were obtained in replicate experiments.