Age-specific Changes in the Proliferation of Ehrlich Ascites Tumor Cells Grown as Solid Tumors

摘要: Reasons for a deceleration of the growth rate with increasing age solid tumors obtained s.c. transplantation 107 cells form Ehrlich ascites in same strain mice were investigated aid thymidine-3H labeling and radioautography. While doubling time tumor mass, exclusive necrotic tissue, changed from 82 hr at 6 days to 204 14 492 26 days, median duration tumor-cell cycle (measured temporal changes percentage labeled mitoses after single injection thymidine-3H) showed only small change (from 16.4 17.8 18.3 hr, respectively). The fraction proliferating cells, measured as ratio observed synthesizing DNA expected synthesis if all cycle, declined value 0.44 0.37 0.32 days. cell death viable portion tumor, discrepancy between production rate, remained close 1.4%/hr ages. However, factor (δ, extent that production) remarkable increase. Overall was faster than because decline removal tissue. latter, inflow dead into compartment this compartment, 0.68%/hr 0.50%/hr 0.42%/hr overall removal, expressed whole unchanged (approximately 0.3%/hr), although loss (φ, progressive increase. Cell disposal (ψ, death) increased but never reached 100% value, thus indicating continued tissue. Within an individual zones high often associated proximity capillaries. Present findings contrast those from, where retardation results primarily rapid prolongation time, lesser moderate slow increase loss.