title: DNA synthesis in the human diploid cell strain WI-38 during in vitro aging: an autoradiography study.
abstract: The percent of cells in a WI-38 cell population which did not incorporate tritiated thymidine (3H-TdR) was determined by autoradiography from the measurement of percent nonlabeled nuclei and the ratio of total cell numbers at the initiation and at the termination of exposure to 3H-TdR. This percentage was minimally affected by factors influencing the proliferation of labeled cells, but was dependent on the population doubling level (PDL). The results suggest the presence, in a proliferating WI-38 population, of subpopulation(s) with an extremely slow rate of S phase entrance. The parameter was useful in estimating, empirically, the doubling potential of a cell population.
mesh_terms: D001345:Autoradiography / Q000379:methods*; D002452:Cell Count; D002453:Cell Cycle; D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism; D002470:Cell Survival; D004247:DNA / Q000096:biosynthesis*; D006801:Humans; D007399:Interphase; D008168:Lung / Q000196:embryology; D013936:Thymidine / Q000378:metabolism; D014316:Tritium
chemical_list: D014316:Tritium; D004247:DNA; D013936:Thymidine