A transmission electron micrograph of the carotid artery of a rat one day after balloon-catheter-induced injury (vascular angioplasty). There is an absence of endothelial cells lining the lumen of the artery, but an aggregation of platelets at the luminal surface. Such injury can occur in humans treated for atherosclerosis by balloon angioplasty. Staining with lectin, Magnification: x 15,000.