Smooth muscle regeneration in the ureter. Electron microscopic and autoradiographic observations.

The cellular events taking place during reconstitution of the rabbit ureteral wall following resection of a portion of its circumference were studied utilizing electron microscopy and autoradiography. It was shown that hyperplasia takes place in the smooth muscle of the ureteral remnant during the first 2 postoperative weeks and that spindle-shaped cells possessing the ultrastructural characteristics of myoblasts migrate from the edges of the remnant into the defect, resulting in regeneration of the muscularis within 5 to 6 weeks of the time of injury.