This project uses electron microscopy, histochemistry, and autoradiography to study the biosynthesis of cartilage proteoglycans and their relationship to collagen in cartilage matrix. Current studies include electron microscopy of the Swarm rat chondrosarcoma and cells cultured from it, including the use of tracers to detect sites of uptake in the chondrocytes, and electron microscopy of abnormal cartilage from mice and humans.