tokens: EXPERIMENTAL DESIGN : Because of their widespread use , the hematologic toxicity following coadministration of dexrazoxane and these three structurally different DNA cleavage enhancers was investigated : Sensitivity of human and murine blood progenitor cells to etoposide , daunorubicin , and doxorubicin +/- dexrazoxane was determined in granulocyte - macrophage colony forming assays .