@article{oai:repo.qst.go.jp:00045047,
 author = {Takahashi, Kenji and Monzen, Satoru and Eguchi-Kasai, Kiyomi and Abe, Yoshinao and Kashiwakura, Ikuo and 高橋 賢次 and 門前 暁 and 笠井 清美 and 阿部 由直 and 柏倉 幾郎},
 issue = {5},
 journal = {Radiation Research},
 month = {Nov},
 note = {Heavy ions have a unique efficacy for tumor control in radiotherapy. To clarify
the effects of heavy-ion beams on hematopoietic stem/progenitor cells, the
effects of carbon-ion beams on megakaryocytopoiesis and thrombopoiesis in CD34(+)
cells derived from human placental and umbilical cord blood were investigated.
The cells were exposed to carbon-ion beams (LET = 50 keV/microm) and then were
treated with thrombopoietin (TPO) alone or TPO plus other cytokines.
Megakaryocytic progenitor cells, such as megakaryocyte colony-forming units
(CFU-Meg), were far more sensitive to carbon-ion beams than to X rays, and no
restoration of carbon-ion beam-irradiated CFU-Meg by treatment with any cytokine 
combination was observed. However, total cell expansion in liquid culture was not
different after either carbon-ion beam or X irradiation of CD34(+) cells. The
activation of gamma-H2AX, a marker of DNA double strand-breaks (DSBs), was
promoted by the cytokine treatment in X-irradiated CD34(+) cells but not in
carbon-ion-irradiated cells. These results showed that carbon-ion beams inflicted
severe damage on megakaryocytopoiesis and thrombopoiesis and that a better
combination of cytokines and other agents may be needed to stimulate the recovery
of hematopoietic cells and repair this damage.},
 pages = {545--551},
 title = {Severe damage of human megakaryocytopoiesis and thrombopoiesis by heavy-ion beam radiation},
 volume = {168},
 year = {2007}
}