Cell counts at different adhesion times.
Fresh male marrow suspensions were inoculated onto pre-established female stromal layers and allowed to adhere for 20 minutes (0.3 hours), 40 minutes (0.7 hours), 1 hour, 6 hours, and 24 hours. Eight experiments are combined. Cell numbers per 25-cm2 flask equivalent in the adherent layer (○) and supernatant (■) were counted in crystal violet on a Neubauer hemacytometer. Both the adherent layer and the supernatant cell counts are significantly lower at 6 and 24 hours than at other time points (P = .004 andP < .0001, respectively, for the adherent layer andP = .01 and P = .004, respectively, for the supernatant). The male percentage in the adherent layer (◊) was determined by FISH; it is lower at 20 minutes than at the other time points (P = .0002). The absolute number of male cells present in the adherent layer (●) and the percentage of the test male cells that were recovered in the adherent layer (⧫) were calculated on the basis of the cell counts, the FISH results, and the number of male cells initially fed on. The male percentage in the adherent layer (◊) and the percentage of test male cells recovered in the adherent layer (⧫) refer to the right-hand y-axis. For both of these, the values at 20 minutes and 24 hours were significantly lower than at the other time points (P = .03 and P < .0001, respectively, for both).
