Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0032463 (polycythemia vera)
 3,374 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Clonogenic cell culture assay was used to evaluate the effect of mast cell growth factor (MGF) on peripheral blood granulocyte-macrophage (GM) progenitors in 26 patients with myeloproliferative disorders (MPDs). MGF alone had a statistically significant stimulatory effect on GM colony formation, as also did interleukin-3 (IL-3) and GM colony-stimulating factor (GM-CSF), although the progenitors could form colonies spontaneously as well. When MGF was combined with either IL-3 or GM-CSF the effect was additive and was as great as that achieved with a mixture of IL-3, GM-CSF, G-CSF and IL-6. The highest colony-forming capacity of all was seen when MGF was added to the above mixture. Within the subgroups of MPDs, the stimulatory effect of MGF was significant in polycythemia vera (PV), essential thrombocythosis (ET) and chronic myelogenous leukemia (CML). MGF was the most potent single factor in PV, while GM-CSF was most effective in idiopathic myelofibrosis and both IL-3 and GM-CSF in CML. The fact that the ability of MGF to induce colony growth varied between the subgroups of MPDs may mean that the target progenitors in these diseases are biologically different. In conclusion, MGF, either alone or with others, was a potent growth factor for GM progenitors in MPDs.
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PMID:The effect of mast cell growth factor on peripheral blood granulocyte-macrophage colony-forming cells in methylcellulose in myeloproliferative disorders. 758 39

The effect of mast cell growth factor (MGF) was studied on erythropoietin (Epo)-dependent and Epo-independent ("spontaneous") erythroid colony formation in patients with polycythemia vera (PV). MGF stimulated both Epo-dependent and Epo-independent erythroid colony formation from PV peripheral blood progenitor cells in vitro at a dose similar to normal erythroid progenitor. In addition, evidence was obtained that the stimulating effect of MGF was a direct effect on the erythroid progenitor and independent of serum. Antibodies against interleukin-1 (IL-1), IL-3, granulocyte-macrophage colony-stimulating factor (GM-CSF), and Epo could not abolish the enhancing effect of MGF. This was also supported by the finding that sorted CD34+ cells could be stimulated by MGF in the presence and absence of Epo. Finally, it was demonstrated that the spontaneous erythroid colony formation could not be ascribed to spontaneous release of MGF in the culture medium since anti-MGF did not affect the colony numbers. In conclusion, MGF has a direct stimulatory effect, independent of serum, on both Epo-dependent and Epo-independent erythroid colony formation in PV.
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PMID:Recombinant human mast cell growth factor supports erythroid colony formation in polycythemia vera in the presence and absence of erythropoietin and serum. 768 83

We studied telomerase regulation and telomere length in hematopoietic progenitor cells from peripheral blood and bone marrow from patients with acute and chronic leukemia and myeloproliferative diseases. CD34+ cells from a total of 93 patients with either acute myeloid leukemia (AML; n = 25), chronic myeloid leukemia (CML; n = 21), chronic lymphocytic leukemia (CLL; n = 18), polycythemia vera (PV; n = 16), or myelodysplastic syndromes (MDS; n = 13) were analyzed before and in 19 patients after ex vivo expansion in the presence of multiple cytokines (kit ligand, interleukin-3, interleukin-6, and granulocyte colony-stimulating factor plus erythropoietin). Compared with hematopoietic progenitor cells from normal donors (n = 108), telomerase activity (TA) was increased 2- to 5-fold in chronic phase (CP)-CML, CLL, PV, and MDS. In AML, accelerated phase (AP) and blastic phase (BP)-CML, basal TA was 10- to 50-fold higher than normal. TA of CP-CML CD34+ cells was up-regulated within 72 h of ex vivo culture, peaked after 1 week, and decreased below detection after 2 weeks. In contrast, TA in AP/BP-CML and AML CD34+ cells was down-regulated after 1 week of culture and decreased further thereafter. The expansion potential of CD34+ cells from patients with leukemia was considerably decreased compared with CD34+ cells from normal donors. The average expansion of cells from leukemic individuals was 6.5-, 2.3-, 0.6-, and 0.2-fold in weeks 1, 2, 3, and 4, respectively, whereas expansion of normal cells was 5- to 15-fold higher. In serial expansion culture, a median telomeric loss of 0.7 kbp was observed during 3-4 weeks of expansion. Our results demonstrate that up-regulation of telomerase is similar in CD34+ cells from CP-CML, CLL, PV, and MDS patients and in normal hematopoietic cells during the first week of culture, whereas in AML and AP/BP-CML, telomerase is high at baseline and down-regulated during expansion culture. High levels of telomerase in leukemic progenitors at baseline may be a feature of both the malignant phenotype and rapid cycling. Telomerase down-regulation during culture of leukemic cells may be due to the decreased expansion potential or repression of normal hematopoiesis, or in AML it may be due to the partial differentiation of AML cells, shown previously to be associated with loss of TA. Telomere shortening during ex vivo expansion correlated with low levels of TA, particularly in chronic leukemic and MDS progenitors where telomerase was insufficient to protect against telomere bp loss during intense proliferation.
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PMID:Telomerase activity and telomere length in acute and chronic leukemia, pre- and post-ex vivo culture. 1067 44