['A direct chemical toxicity of dimethyl sulfoxide (DMSO) to hematopoietic progenitor cells has been suggested. However, a recent study failed to corroborate these earlier findings. Thus, a series of experiments was undertaken to address this issue.', 'Bone marrow was collected from 18 donors and cryopreserved with 10 percent (vol/vol) DMSO. Aliquots of frozen bone marrow were thawed, diluted with ACD-A to 8 percent (vol/vol) DMSO, and allowed to remain in DMSO for up to 2 hours before mononuclear cells were plated for colony-forming assays. After 14 days in culture, burst-forming units-erythroid, colony-forming units--granulocyte/macrophage, and colony-forming units--granulocyte/erythrocyte/macrophage/megakaryocyte colonies were enumerated.', 'There was no significant difference (p > 0.5) seen in colony formation over the 2-hour exposure to DMSO.'] Are hematopoietic progenitor cells resistant to dimethyl sulfoxide toxicity?