Example of estimation of SL2 tumour cell numbers within different compartments of the cell cycle 10 h after in vivo labelling with BrdUrd. A. Flow cytometric dual parameter dot plot of BrdUrd content (log FITC fluorescence) vs. DNA content (propidium iodide fluorescence) with a gate set for BrdUrd positive cells. B. DNA histogram analysis of BrdUrd positive cells; M1 indicates labelled divided G1 cells (G1
ld); M2 indicates labelled divided S cells (Sld); M3 indicates labelled undivided S cells (Slu); M4 indicates labelled undivided G2 cells (G2
lu). C. The same DNA histogram as in B, shown at higher magnification; Sld compartment is separated from Slu compartment by the channel corresponding to the lowest number of events (indicated by dotted vertical line). Total number of cells within each of these markers is obtained using statistics option of WinMDI 2.8 software.