Increased levels of pletelet-derived growth factor in vitreous fluid of patients with proliferative diabetic retinopathy. - Freyberger,H.; Brocker,M.; Yakut,H.; Hammer,J.; Effert,R.; Schifferdecker,E.; Schatz,H.; Derwahl,M. (Exp Clin Endocrinol Diabetes, 2000)