Absolute numbers of F+ and F−A+ cells.

Cultures were treated with TGFβ from day 0 to day 4, then propagated without TGFβ, with further subcultivation and dilution on days 7 (1:10), 10 (1:5), and 13 (1:5). Absolute numbers of F+ and F−A+ cells per culture were determined on days 7, 10, 13, and 16. (A) Time course of proliferation. Representative example from one experiment. Overall cell production is calculated by multiplying total cell numbers per culture with all preceding culture dilution factors. Open symbols: F−A+ cells; full symbols: F+ cells. Triangles: TGFβ-treated cultures; circles: controls. Inset: photographs of day 18 cultures, after reseeding on day 13. Left: control; right: TGF-treated. (B) Ratios of cell numbers in TGFβ-treated and control cultures (N[TGF] / N[CON]), as a function of culture time. Pairs of F+ and F−A+ values from individual experiments are identified by connecting lines. Median values are indicated by horizontal bars, and individual values are shown (open circles) to indicate range and distribution. The increase in the ratios (N[TGF]/N[CON]) between day 7 and day 16 is statistically significant, with P < .03 for F+ cells andP < .02 for F−A+ cells. The difference in the ratios N(TGF)/N(CON) between F+ and F−A+ cells is significant withP < .001 at all time points.