Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0085632 (apathy)
 4,089 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Mobilization of stem and progenitor cells into blood, which facilitates the collection of blood-derived autograft and allograft products, can be accomplished with administration of myelosuppressive chemotherapy, hematopoietic growth factors, or both. Autologous donor indifference to mobilization attempts has been correlated with prior administration of chemotherapy and radiation therapy. To investigate whether concurrent administration of radiation therapy inhibits mobilization, five daily injections of a potent combination of mobilizing cytokines, 500 U/kg erythropoietin (EPO) plus 15 microg/kg G-CSF, were administered each morning to Balb/c mice. Each afternoon, a 2 Gy fraction of Co-60 radiation was administered to either the lower limb or the upper or lower hemibody. Each day, mice were necropsied, and blood stem cell mobilization was determined by assaying the number of hematopoietic colony-forming cells in the blood and in the spleen. Unirradiated cytokine-injected mice showed a significant mobilization effect evident as increased colony-forming cells in blood and spleen compared with saline-injected unirradiated controls. The irradiated mice showed markedly inhibited or absent mobilization regardless of the part of the body irradiated. To investigate the mechanism of radiation-induced mobilization inhibition, heparinized plasma was obtained from mice whose lower bodies were irradiated with 2 Gy 18 h previously, and 0.5 ml was injected i.v. into intact mice 10 min before they received 15 microg/kg G-CSF and 500 U/kg EPO. Unlike mice that received G-CSF + EPO only and showed mobilization of progenitors from marrow to spleen, recipients of plasma from irradiated mice before and after cytokine administration showed significantly reduced mobilization of progenitors. Thus, radiation-induced inhibition of stem cell mobilization is mediated by an unidentified circulating factor.
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PMID:Concurrent partial body radiation prevents cytokine mobilization of blood progenitor cells: an effect mediated by a circulating factor. 973 65

Deliberately increasing the number of hematopoietic stem and progenitor cells in the circulation allows faster and more efficient collection of sufficient cells for transplantation in both the allogeneic and autologous settings. These mobilized stem cells, when transplanted, provide quicker hematopoietic recovery for the patient than do nonmobilized blood stem cells or steady-state marrow-derived stem cells. Currently used clinical procedures to produce stem cell mobilization include administration of G-CSF or GM-CSF, either as single agents or in combination with myelosuppressive chemotherapy. Some autologous blood stem cell donors exhibit indifference to currently applied mobilization therapies. This failure to mobilize has been associated with prior stem cell toxic therapy, e.g., radiation therapy and chemotherapy, but the association is incomplete. The observation that occasional normal donors have failed to respond to mobilization therapy indicates that factors other than stem cell damage could also be involved. Recently, a murine model has provided evidence that a circulating factor inhibits mobilization in some settings. Preliminary investigations have suggested that a circulating factor may inhibit mobilization of human hematopoietic progenitor cells in some instances. Studies to identify this factor(s) are underway. The mechanisms of blood stem cell mobilization are still poorly understood and there continues to be the potential to improve this process.
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PMID:Mobilization of blood stem cells. 1101 56