• A cellular analysis of long-term haematopoietic damage in mice after repeated treatment with cyclophosphamide.

      Molineux, Graham; Xu, Cheng Xiong; Hendry, Jolyon H; Testa, Nydia G; Paterson Laboratories, Christie Hospital, Manchester M20 9BX UK (1986)
      Following repeated treatment of mice with cyclophosphamide (5 X 200 mg/kg) it was found that slight, but significant, residual marrow damage persisted for at least half the lifespan of the animals. This long-term damage occurred despite preferential sparing of those multi-potential haematopoietic cells (CFU-S) that had a high self-renewal capacity after each step of the multistep regimen and despite a smaller CFU-S kill after each successive dose. The damage was characterized by low mean numbers of CFU-S and stromal colony-forming cells (CFU-F) which were around 70% of control values. Examination of individual animals revealed that the majority had slightly subnormal numbers of CFU-S and CFU-F, with only a few suffering a more severe injury, including 8% of mice with clinical hypoplasia or myelodysplasia.
    • The radial distribution of fibroblastic colony-forming units in mouse femoral marrow.

      Xu, Cheng Xiong; Hendry, Jolyon H (1981-09)
      The distribution of fibroblastic colony forming units (CFU-F) in mouse femoral marrow was investigated using a method which separates bone marrow cells into two regional fractions of varying size. It is shown that the concentration of CFU-F decreases almost linearly from the femoral axis (800-1,000 CFU-F per 10(7) bone marrow cells) to the bone surface (300 CFU-F per 10(7) cells). When irradiated axial or marginal cells were added into cultures as feeder cells, the colony numbers produced by both axial or marginal CFU-F were increased by about 50% and the higher concentration in the axial regions remained. The survival curve for CFU-F in both regions was characterised by a Do value of 1.54 +/- 0.11 Gy and an extrapolation number of 2.60 +/- 0.38. The results are compared to the distributions of haemopoietic stem cells and committed progenitor cells.
    • The response of stromal progenitor cells in mouse marrow to graded repeated doses of X rays or neutrons.

      Xu, Cheng Xiong; Hendry, Jolyon H; Testa, Nydia G; Paterson Laboratories, Christie Hospital and Holt Radium Institute, Manchester M20 9BX (1983-10)
      After four repeated doses of 1.5 Gy X rays to mice (3-week intervals), the number of colonies containing fibroblasts that could be grown in vitro from femoral marrow recovered to control numbers by 80 days. After four higher doses, recovery was incomplete, and after four doses of 4.5 Gy, the number was half of the control level up to 1 year after irradiation. After four doses of 14.7 MeV neutrons, no threshold was detected for this late effect, and the RBE was about 2 at 4.5 Gy X rays and about 6 at 1.5 Gy X rays. The RBE for the acute effect on the stromal progenitor cells was also about 2 at 4.5 Gy X rays. The stromal progenitor cells could not be spared relative to hemopoietic stem cells (CFU-S) after neutrons, in contrast to the sparing observed after low-dose fractions of X rays. Experiments with local X irradiations of the leg, and with subcutaneous transplants of femora, revealed no significant recovery of stromal progenitor cells due to migration. However, recovery in situ could be enhanced slightly by marrow grafts i.v.
    • Stromal colonies from mouse marrow: characterization of cell types, optimization of plating efficiency and its effect on radiosensitivity.

      Xu, Cheng Xiong; Hendry, Jolyon H; Testa, Nydia G; Allen, Terence D; Paterson Laboratories, Christie Hospital and Holt Radium Institute, Withington, Manchester M20 9BX (1983-05)
      Modifications to the colony assay in vitro for stromal progenitor cells in mouse femoral marrow have been studied so as to optimize the efficiency of colony formation (CFE). The highest reproducible concentration achieved was about 30 colonies (containing fibroblasts, macrophages and endothelioid cells) per 10(6) nucleated marrow cells (range 20-50) in mice 3-4 months old, and higher by 50% in mice 14-15 months old. Each of many slight technical modifications could reduce these values by more than 30%. The importance of optimization was demonstrated by a reduced radiosensitivity when the CFE was reduced by a factor of 3 using alpha-medium stored at 4 degrees C for 15 days. The D0 value was 3.9 +/- 0.8 Gy compared to 1.6 +/- 0.1 Gy using freshly prepared medium, and this could be due to the selection of a radioresistant subpopulation. The modifications studied may partly explain the marked variations in CFE and in radiosensitivity reported in the literature.