using repeated cloning and treatment with cis-hpl ( 200 micrograms/ml ) , an analogue of a procollagen precursor inhibitory to the growth of collagen-synthesizing cells of mesenchymal origin , clonally premature epithelial cell lines were isolated from fetal sgh lungs cultured on the 15th day of gestation .
C0033235
procollagen
C0009325
collagen