Fig. 1

Growth curve and morphology of human diploid fetus-derived fibroblasts (TIG-3S). a Average proliferation of TIG-3S cells plotted as PDL for approximately 180-day culture (n = 3). b Bar graph representation of the average doubling time of the cells at each PDL (mean + SE, n = 4–22). c Cell shapes are shown at PDLs 27, 40, 50, 77, and 94. d TIG-3S cells at PDLs 43 and 83 were stained with SA-β-galactosidase. The upper panels are a magnification of the squared area in the lower panels. The arrows indicate stained cells