addition of exogenous glycosaminoglycans ( chondroitin-4-sulfate , chondroitin-6-sulfate , dermatan sulfate , hyaluronic acid , heparan sulfate , heparin ) at 100 microgram/ml to the culture media during the last 7 to 10 population doublings before phase out did not increase the total number of population-doublings .
C0017973
glycosaminoglycans
C0019143
heparan sulfate