title: Residual toxicity in hematopoietic cells following a single dose of methylnitrosourea.
abstract: The residual injury to the proliferation capability of hemopoietic stem cells (CFU-S) which results from their exposure to leukemogenic agents was evaluated in mice given a single leukemogenic dose of methyl nitrosourea (MNU 50 mg/kg body weight, i.v.). Bone marrow cellularity, splenic weight, number of CFU-S and the proportion of cycling to noncycling CFU-S were measured in an effort to detect and acute and residual injury to the CFU-S from mice given MNU 21 and 3 days earlier. Marrow cells were also transferred into lethally irradiated mice to observe the self-renewal capability of the CFU-S in the recipient spleen and bone marrow. The results of these measurements show that the CFU-S in marrow from mice given 50 mg/kg of MNU 21 days earlier still have a defective ability for self-renewal, although the total cellularity, number of CFU-S and proportion of cycling and noncycling CFU-S in the donor have returned to the normal range. The relationship of this self-renewal defect to the development of leukemia after this leukemogenic dose of MNU is not known.
mesh_terms: D000818:Animals; D001853:Bone Marrow / Q000187:drug effects*; D001854:Bone Marrow Cells; D002455:Cell Division; D003114:Colony-Forming Units Assay; D004261:DNA Replication; D008297:Male; D008770:Methylnitrosourea / Q000633:toxicity*; D051379:Mice; D009607:Nitrosourea Compounds / Q000633:toxicity*; D011828:Radiation Chimera; D013154:Spleen / Q000166:cytology
chemical_list: D009607:Nitrosourea Compounds; D008770:Methylnitrosourea