Cell Kinetic Analysis of a Human Melanoma In Vitro and In Vivo-Vitro

Summary

The cell kinetic parameters of the same human melanoma maintained in tissue culture and analyzed in vitro and in vivo-vitro were determined. The in vitro data were obtained by the percent labeled mitosis method (after a short exposure to tritiated thymidine), by the doublelabeling technique, and by the continuous-labeling technique. The in vivo-vitro procedure utilized the double-labeling technique (tritium-and carbon-14-labeled thymidine). The values For cells growing in vitro (with the corresponding in vivo-vitro values given in parentheses) were as follows: labeling index = 0.25 (0.23); DNA synthesis time (T_s) = 14.5 hours (15.9); G₂+0.7 M = 5.3 hours; G₁ = 16.3 hours; cell-cycle time = 36.1 hours(40); and growth fraction = 0.62 (0.58). T_s was determined in 2 other ways: 1) Cells growing in culture were deuble-labeled (T_s = 15.6 hours); and 2) cells From a bone marrow aspirate were double-labeled in vitro (T_s = 15.7 hours).