Marrow repopulating ability: GM-CFU, ranked in ascending order, on day 13 in femurs of recipients of bone marrow of mice treated with 0.3 μg TPO IP 2 hours after each fraction of 3 Gy TBI (▧) in comparison with those of recipients of control marrow (□) of mice that did not receive TPO. Upper panel: a total of 25 mice were injected with bone marrow (the content of 1 femur, 24 hours after TBI) of TPO-treated mice of which only 5 mice had more than 10 GM-CFU per femur, and 17 (surviving of 20 injected) mice with bone marrow of placebo-treated mice of which 10 had more than 10 GM-CFU per femur. Results from two experiments. This difference is highly significant (P = .01, Fisher’s exact test). Upper middle panel: 10 mice were injected with the standard 105 bone marrow cells from each of the groups 1 month after TBI, of which in each recipient group 9 mice survived and 5 mice had more than 10 GM-CFU per femur. Lower middle panel: 10 mice were injected with the standard 105 bone marrow cells from each of the groups 3 months after TBI, of which in the recipient group of the TPO-treated mice 1 mouse died before day 13 and 1 mouse had less than 10 GM-CFU/femur. Lower panel: 20 mice were injected with the standard 105bone marrow cells from normal, untreated donors for comparison.
