Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0026986 (myelodysplastic syndrome)
 14,926 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Stem cell factor (SCF) is characterized by its capacity to synergize dramatically with other haemopoietic growth factors in in vitro erythroid, myeloid, and lymphoid progenitor culture systems. We have measured serum SCF concentrations by enzyme immunoassay in 85 patients with myelodysplasia (MDS). Serum samples were taken in 1988-89 and in 1991-92 and stored at -20 degrees C. Mean serum SCF concentration in the MDS patients was 2.81 ng/ml (range 0.6-8.0). This was significantly lower (P = 0.0001) than the values for 234 normal subjects; mean 3.30 ng/ml (range 1.3-8.0). No significant relationship between SCF concentration and peripheral blood counts, bone marrow parameters, red cell transfusion status, survival or FAB subtype was found, although a trend of decreasing SCF concentration from refractory anaemia through sideroblastic anaemia and chronic myelomonocytic leukaemia to refractory anaemia with excess blasts was seen. The reduced SCF serum concentration in some patients with myelodysplasia suggests a rationale for therapy with recombinant SCF in these patients.
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PMID:Serum stem cell factor concentration in patients with myelodysplastic syndromes. 750 11

Stem cell factor (SCF), the ligand of the c-kit receptor, is a potent enhancing cytokine for haematopoietic cells in the presence of IL-3, GM-CSF and erythropoietin (Epo). In the clonogenic assays of 63 MDS patients, the addition of rh-SCF + GM-CSF and/or IL-3 induced a significant increase (p < 0.001) in the number and size of CFU-GM. Never reaching the levels of controls, this increase was seen in all FAB subtypes, but particularly in RA. There was no significant increase in cluster formation, even in RAEB or RAEBt. Rh-SCF (10 ng/ml) led to mean increases of up to 26 times in the number of Epo-dependent BFU-E colonies, particularly in RA (p < 0.001) and RAEB (p < 0.05). Individual responses varied widely (especially in RA) from no response to supranormal levels. Added to the weekly refeed of 37 MDS LTBMC, SCF (10 ng/ml) induced only a 7% mean increase in both cell output and the number of clonogenic cells recovered in the supernatant. Immunohistochemical examination of the supernatant showed significant increases in differentiating myeloid cells in all examined cases, and in erythroid cells in 3 cases; blast cells increased in only 3 cases. These data suggest that rh-SCF is capable of at least partially reversing defective MDS myeloid haematopoiesis, and leads no overt risk of leukaemic transformation. Its potent effect on erythroid cells is encouraging for future clinical applications in patients, particularly if they are selected by means of in vitro tests.
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PMID:Effects of recombinant human stem cell factor (rh-SCF) on colony formation and long-term bone marrow cultures (LTBMC) in patients with myelodysplastic syndromes. 750 65

Human recombinant stem cell factor (rSCF) was tested for its capability of improving the defective growth of hemopoietic progenitors in 28 cases of myelodysplastic syndromes (MDS). In vitro growth and response to rSCF were quite variable. However, in most cases, rSCF stimulated CFU-GM growth induced by rG-CSF, rGM-CSF, rIL-3, 5637 conditioned medium (50-1400% enhancement). rSCF effect was slightly more evident on day 14 CFU-GM and in the presence of rIL-3. BFU-E growth induced by rEPO or rIL-3 + rEPO was enhanced by rSCF in about 50% of cases, in linear correlation with the levels of patients' hemoglobin. rSCF did not increase CFU-E growth, whereas it slightly stimulated CFU-Mk in 33% of the cases. EPO, SCF and, particularly, their combination, enhanced the recovery of normal CFU-E and BFU-E after 7 days of liquid culture. This was less evident in cultures of MDS patients. Conversely, CFU-GM generation in long term liquid cultures, although highly variable, was stimulated by rSCF and, above all, by rSCF + rG-CSF, similarly to what was observed with normal bone marrow samples. SCF seems to enhance in vitro erythropoiesis only in MDS cases presenting without severe anemia. It has little effect on megakaryocytopoiesis, while it seems to be more active on CFU-GM growth and maintenance.
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PMID:Stem cell factor improvement of proliferation and maintenance of hemopoietic progenitors in myelodysplastic syndromes. 750 32

The in vitro colony-forming capacities of marrow CD34-positive (CD34+) cells from 25 patients with myelodysplastic syndromes (MDS) were studied. In all patients this purified cell population showed erythroid (burst-forming unit erythroid; BFU-E) or non-erythroid colony growth, both of which were more restricted than non-purified mononuclear cell population under stimulation with erythropoietin (EPO) or granulocyte/macrophage colony-stimulating factor (GM-CSF) alone. MDS patients examined were put into two groups; refractory anemia (RA) or RA with ringed sideroblasts (RA/RARS) and RA with excess of blasts (RAEB) or RAEB in transformation (RAEB/RAEB-t). The CD34+ cells of both RA/RARS and RAEB/RAEB-t exhibited a similarity to the cells of normal individuals in their responsiveness to the addition of interleukin 6 (IL-6), IL-3 or stem cell factor (SCF). SCF caused powerful but highly variable responses in both erythroid and nonerythroid colony formation as compared with IL-6 or IL-3. We demonstrated that MDS marrow hematopoietic progenitor cells reactive to GM-CSF or EPO were additionally stimulated with early-acting hematopoietic growth factors including IL-6, IL-3 and SCF in a fashion similar to those of normal individuals.
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PMID:Growth analysis of marrow CD34-positive hematopoietic progenitor cells in patients with myelodysplastic syndromes. 751 49

Clonality of marrow hematopoietic progenitor cells in myelodysplastic syndromes (MDS) was analyzed by X-chromosome inactivation pattern using polymerase chain reaction (PCR). Five female patients were included in this study; two with refractory anemia (RA) and three with RA with excess blasts (RAEB). They were heterozygous for BstXI restriction fragment length polymorphisms (RFLP) of the X-chromosome-linked phosphoglycerate kinase (PGK) gene. In each patient, erythroid and nonerythroid colonies, grown in the presence of erythropoietin and granulocyte-macrophage colony-stimulating factor (GM-CSF), exhibited no remarkable difference in clonal constitution. Two patients showed only one methylation pattern, suggesting the monoclonal origin of hematopoietic progenitor cells. Colonies of two other patients exhibited predominant and minor methylation patterns in PGK gene, indicating that nonclonal progenitor cells remain a minor population. The bone marrow of one patient appeared to contain a greater proportion of nonclonal progenitors. Stem cell factor (SCF), a potent colony-stimulating factor, enhanced both erythroid and nonerythroid colony formation. However, it did not notably alter the clonal constitutions. We conclude that nonclonal hematopoietic progenitor cells can persist in a substantial number of MDS patients.
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PMID:Evidence for nonclonal hematopoietic progenitor cell populations in bone marrow of patients with myelodysplastic syndromes. 751 21

We studied mRNA expression of the cytokine granulocyte-colony stimulating factor (G-CSF), interleukin-1 beta (IL-1 beta), IL-6, IL-8 and stem cell factor of stromal cells derived from bone marrows of nine normal volunteers, eight patients with aplastic anaemia (AA) and seven patients with myelodysplastic syndrome (MDS). The proportion of endothelial cells, macrophages, fibroblast-like cells and adipocytes in stromal cells showed no differences between normal volunteers and the patients. Levels of cytokine mRNA expression were determined by reverse transcription-polymerase chain reaction. Spontaneous expression occurred and this was augmented by LPS stimulation in cells of all the normal volunteers and in most patients. When stimulated by LPS, the mean G-CSF and IL-1 beta mRNA expressions in patients with AA were significantly higher than normal volunteers, but there was one patient showing lower IL-1 beta, IL-6 and IL-8 expression with no response to LPS. LPS-induced IL-6 and IL-8 expression of two patients with MDS were significantly higher than normal. The spontaneous and LPS-induced protein concentration of G-CSF, IL-6 and IL-8 in culture supernatants from 15, 10 and four patients, correlated well with the mRNA expression. The correlation coefficients were 0 x 92, 0 x 78 and 0 x 91, respectively. In conclusion, there were a few patients whose aetiology appeared to be reduction of stromal cytokine expression in AA, but most patients with AA and MDS expressed normal or high levels of cytokine mRNA.
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PMID:Cytokine mRNA expression of bone marrow stromal cells from patients with aplastic anaemia and myelodysplastic syndrome. 752 19

Using clonogenic assay we investigated the effect of stem cell factor (SCF) on the in vitro growth of clonogenic precursor cells from acute myeloid leukemia (AML) and myelodysplastic syndromes (MDS) in the presence or absence of recombinant human erythropoietin (rhEpo) or recombinant human granulocyte colony-stimulating factor (rhG-CSF). SCF as a single factor did not induce significant colony formation, and even in the presence of rhEPO or rhG-CSF it very weakly stimulated erythroid colony formation and was rarely capable of inducing myeloid colony formation by clonogenic leukemic cells. In culture dishes supplemented with SCF, both myeloid and erythroid colony formations were dramatically enhanced in MDS, regarding both colony number and size. Colony-formation abilities by MDS progenitors were improved following costimulation with SCF and rhEpo. These results suggest that SCF may have a therapeutic role in restoring hematopoiesis in patients with MDS.
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PMID:Effect of stem cell factor (c-kit ligand) on clonogenic leukemic precursor cells: synergy with other hematopoietic growth factors. 752 82

We evaluated the effects of transforming growth factor-beta 1 (TGF-beta 1) on the growth of hematopoietic progenitors in normal donors and in patients with hematologic malignancies now designed as clonal disorders of multipotential stem cells. TGF-beta 1 at 80 pM exhibited differential effects on the normal hematopoietic progenitors when cells were stimulated with different growth factors, such as G-CSF, GM-CSF, interleukin-3 (IL-3), or stem cell factor (SCF). The suppressive effect by TGF-beta 1 was increased for growth with GM-CSF, IL-3, and SCF, and growth with G-CSF was unaffected in hematologic malignancies, TGF-beta 1 suppression for growth with G-CSF was increased for essential thrombocythemia (ET) and polycythemia vera; chronic myelogenous leukemia (CML) in chronic phase; CML in accelerated phase; CML in myeloid crisis; myelodysplastic syndrome (MDS) in refractory anemia; MDS in refractory anemia with an excess of blasts; and acute myeloblastic leukemia (AML). In CML-myeloid crisis and AML, TGF-beta 1 almost completely abolished the growth, with some patient-to-patient variation. The mean ED50s for the growth of leukemic blast progenitors were 1.6, 1.2, 0.7, and 0.2 pM in the presence of G-CSF, GM-CSF, IL-3, and SCF, respectively, c-myc and c-myb antisense oligonucleotides significantly suppressed the growth of leukemic blast progenitors, but not that of clonogenic cells from normal donors and patients with ET. We also demonstrated that TGF-beta 1 inhibits mRNA expression by AML blasts for c-myc and/or c-myb. When the data are taken together, growth suppression by TGF-beta 1 appears to increase with the progression of clonal evolution in hematologic malignancies.
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PMID:Differential effects of TGF-beta 1 on normal and leukemic human hematopoietic cell proliferation. 754 18

The KIT proto-oncogene encodes a tyrosine kinase receptor which plays a critical role in haemopoiesis. We have screened genomic DNA from bone marrow mononuclear cells of 46 patients with myelodysplasia (MDS) for mutations/deletions of exons 6, 13, 17, and 21 of the KIT gene (stem cell factor receptor) using polymerase chain reaction (PCR), polyacrylamide gel electrophoresis, and autoradiography to detect single-stranded conformational polymorphisms (SSCP). These exons include positions analogous to those mutated in the FMS gene (colony-stimulating factor-1 receptor) in myelodysplastic syndrome (MDS) and mutated/deleted in the Dominant White Spotting mouse (W locus) which results in macrocytic anaemia. Two different gel running conditions were used for each exon. Polymorphisms were identified only at 4 degrees C in exon 17 (three out of 44 MDS samples and two of 21 DNA samples from normal subjects), and in the non-coding region of exon 21 (five out of 34 MDS samples and seven out of 19 normals). Direct sequencing identified a G to A base change at nucleotide 3169 within exon 21, and a C to T change at position 2415 in exon 17. No conformational changes suggestive of mutations or deletions have been found to date, although we cannot rule out low frequency clonal abnormalities undetectable by our method, which has a sensitivity in our hands of approximately 5%. Polymorphisms occur frequently in the KIT gene. Together with this study, a total of five have been described.
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PMID:Two new polymorphisms but no mutations of the KIT gene in patients with myelodysplasia at positions corresponding to human FMS and murine W locus mutational hot spots. 769 8

The clonal growth of progenitor cells from myelodysplastic syndromes (MDS) can be subdivided into four growth patterns: (1) normal, (2) no growth or low plating efficiency, (3) low colony and high cluster number, and (4) normal or high colony number with a large number of clusters. The former two (1 and 2) can be referred to as nonleukemic patterns and latter two (3 and 4) as leukemic. In a search for a role for cytokines in leukemic-type growth of MDS progenitor cells, marrow CD34+ cells were purified up to 94% for 8 normal individuals and 88% for 12 MDS patients, using monoclonal antibodies and immunomagnetic microspheres (MDS CD34+ cells). The purified CD34+ cells were cultured for 14 days with various combinations of cytokines, including recombinant human macrophage colony-stimulating factor (rM-CSF), granulocyte-CSF (rG-CSF), granulocyte-macrophage-CSF (rGM-CSF), interleukin-3 (rIL-3), and stem cell factor (SCF; a ligand for c-kit) in serum-free medium. The clonal growth of MDS CD34+ cells supported by a combination of all of the above cytokines was subdivided into the two patterns of leukemic or nonleukemic, and then the role of individual or combined cytokines in proliferation and differentiation of MDS CD34+ cells was analyzed in each group. Evidence we obtained showed that SCF plays a central role in the leukemic-type growth of MDS CD34+ cells and that G-CSF, GM-CSF; and/or IL-3 synergize with SCF to increase undifferentiated blast cell colonies and clusters over that seen in normal CD34+ cells. SCF is present in either normal or MDS plasma at a level of nanograms per milliliter, and this physiologic concentration of SCF can stimulate progenitor cells. This means that progenitor cells are continuously exposed to stimulation by SCF in vivo and that MDS leukemic cells have a growth advantage over normal blast cells. This depends, at least in part, on cytokines such as G-CSF, GM-CSF, IL-3, and SCF.
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PMID:Role of cytokines in leukemic type growth of myelodysplastic CD34+ cells. 870 90


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