(a) Two representative confocal images at high power from lungs loaded with DHE, treated with 20-5,14-HEDE or vehicle, fixed, and then probed with a primary antibody to PECAM-1. The white arrows identify PECAM associated cells, whereas the two yellow arrows show DHE fluorescence in cells that do not appear to be associated with PECAM-1. (b) DHE fluorescence in more than 1000 ROIs each identified as PECAM-1 associated, in confocal images from lung slices treated with either vehicle or 20-5,14-HEDE. Data are normalized to mean fluorescence in vehicle-treated samples (since paired samples from 4 separate rats were obtained in different settings). 20-5,14-HEDE increased ROS in pulmonary artery ECs as compared to vehicle (ethanol) treatments.