Effects of bolus PEG-rHuMGDF on megakaryocyte ploidy frequency distribution. The frequency distribution of ploidy classes from 2N to 128N is shown baseline for 8 normal subjects (open bars). After PEG-rHuMGDF administration, ploidy frequency distributions are compared in 6 normal subjects evaluated on day 8 (acute hatching), day 12 (grave hatching), and day 18 (double cross-hatching). Placebo subjects yielded data consistent with baseline distribution. The proportion of 16N cells was significantly reduced during the period of induced thrombocytosis on day 8 and day 12, consistent with the decreased megakaryocyte volumes reported in Table 3. Variance about the mean values is ± SD.