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)

The efficacy of hexamethylene bisacetamide (HMBA), a potent polar-planar solvent which is capable of differentiating leukemias and solid tumors in vitro at clinically achievable concentrations, was studied in 16 patients with severe myelodysplastic syndromes (MDS). An adaptive control dosing algorithm was used to maintain HMBA steady-state concentrations (Css) within a narrow therapeutic window (1-2 mM) for five days every four weeks. Despite achieving the target HMBA Css during at least two courses in each of 15 patients, HMBA did not produce clinically relevant improvements in blood cell counts nor in other functional indices. Instead, HMBA induced cytopenias in the majority of these patients, most of whom had preexisting cytopenias and limited hematopoietic reserves. These disappointing results correlated with concurrent in vitro bone marrow studies from these patients in which both the HMBA concentrations that were optimal for differentiation in vitro (2-5 mM) and the HMBA Css that were achieved in this study (1-2 mM) substantially inhibited the growth of granulocyte-macrophage colony-forming units and erythroid burst-forming units. Although the mechanism responsible for the anti-proliferative effects of HMBA on hematopoietic progenitors (cytotoxicity versus terminal differentiation) could not be determined, the induction of cytopenias and lack of significant clinical improvements suggest that HMBA is cytotoxic and will not be useful alone as a differentiating agent on this schedule of administration in the treatment of MDS.
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PMID:Hexamethylene bisacetamide in myelodysplastic syndrome: effect of five-day exposure to maximal therapeutic concentrations. 160 91

Acute myelomonocytic leukemia develops in 10-30% of irradiated (300 rad) SJL/J mice, after a lag period of around one year. Additional treatment with dexamethasone shortly after irradiation increased leukemia incidence up to 50%. Experiments were conducted in order to demonstrate the existence of preleukemic cells in irradiated mice and to explore the possible role of dexamethasone, cyclophosphamide, and different hemopoietic growth factors on their promotion to overt leukemia. Transplantation of bone marrow cells from mice exposed to 300 rad plus dexamethasone into appropriate recipients, performed 4-5 months after leukemogenic treatment, resulted in acute myeloid leukemia (AML) development of donor origin in 70% of the recipients. Transfer of fractionated preleukemic bone marrow showed that the highest AML incidence developed in the recipients of fractions enriched in early hemopoietic precursors. The promoting effect of dexamethasone on preleukemic cells was confirmed by demonstrating its similar coleukemogenic effect whether administered within several hours or 130 days after radiation. Treatment with cyclophosphamide shortly after radiation could not replace the dexamethasone effect but was found to be complementary to the coleukemogenic effect of dexamethasone. Early administration of hemopoietic growth factors (starting 14 days after radiation and dexamethasone) showed that colony-stimulating factor (CSF) 1 increased the AML incidence (75%) and reduced its latency. Treatment with recombinant granulocyte-CSF (rG-CSF) had a reduced effect and recombinant granulocyte-macrophage CSF (rGM-CSF) had no promoting effect. However, administration of different factors several months after the leukemogenic treatment revealed that rGM-CSF increased AML incidence (75%) and shortened its latency, whereas rG-CSF and CSF-1 had no effect. In contrast, the late administration of recombinant interleukin 6 reduced AML incidence significantly (23%). The present results indicate that murine radiation induced AML is a multiphase process involving radiation induced preleukemia that can be promoted by different treatments.
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PMID:Initiation and promotion in radiation-induced myeloid leukemia. 162 87

Colony stimulating factors (CSF) for white blood cells are formed in the bone-marrow and regulate proliferation and differentiation of the myeloid cells. Several of these hormones are cloned and manufactured by a recombinant technique for clinical use. The granulocyte-macrophage-colony-stimulating factor (GM-CSF) and the granulocyte-colony-stimulating factor (G-CSF) both belong to this group. Trials are still at the commencing stage. In vitro investigations, animal experiments and human experiments have rendered promising results. After intensive chemotherapy followed by treatment with GM-CSF and G-CSF, it has been demonstrated that the period of neutropenia following bone-marrow suppression is abbreviated. Accelerated bone-marrow regeneration and reduced tendencies to infection have been demonstrated compared with so-called control patients. In patients with the myelodysplastic syndrome, marked increase in the neutrophile granulocytes in the peripheral blood has been observed during treatment with growth factors. Long-term treatment with G-CSF has proved particularly effective in chronic idiopathic and cyclic neutropenia. On the other hand, the growth factors can scarcely improve the prognosis in severe aplastic anaemia. Animal experiments and a single human trial suggest that G-CSF and GM-CSF treatment are indicated in bone-marrow insufficiency secondary to radioactive irradiation accidents. GM-CSF has normalized the leucocyte counts in AIDS patients with leucopenia without any marked alteration in the tendency to infection. Future studies will show whether simultaneous treatment with growth factors and anti-viral and anti-leukaemic treatments, respectively, can improve the therapeutic results.
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PMID:[Myeloid hemopoietic growth factors. Therapeutic possibilities and clinical experiences]. 170 May 24

Relapse continues to be a problem after bone marrow transplantation (BMT) for hematologic malignancies, particularly in recipients of autologous or T-cell-depleted allogeneic grafts and in patients with advanced disease. Interferon (IFN) has shown antiproliferative activity in several malignant hematologic diseases and potentially may be of benefit when administered early after BMT when the number of residual cells is minimal. We tested in a phase I study the maximum tolerated daily dose of recombinant IFN alpha-2b in patients who had received a transplant for a disease at high risk for relapse (acute myeloid leukemia or non-Hodgkin's lymphoma beyond first remission, advanced myelodysplastic syndrome, acute lymphoblastic leukemia at any stage, chronic myeloid leukemia in accelerated or blast phase. Recombinant IFN alpha-2b was started at a dose of 0.5 x 10(6) IU/m2 and escalated by 0.5 x 10(6) IU/m2 in groups of three or four patients. The intention was to administer IFN as soon as stable engraftment after BMT was achieved (defined as an absolute neutrophil count of greater than 2.0 x 10(9)/L and platelet count greater than 100 x 10(9)/L for 5 consecutive days) and continued for 2 months. A total of 14 patients were enrolled after autologous (n = 3) or allogeneic (n = 11) BMT. Dose-limiting toxicity was myelosuppression. Significant (grade 2 to 4) neutropenia and thrombocytopenia led to discontinuation or dose reduction in five of eight patients receiving 1.5 x 10(6) or 2 x 10(6) IU/m2 IFN. Mild to moderate (grade 1 or 2) anorexia, weight loss, and fatigue occurred in the majority of patients independent of the IFN dose. De novo acute GVHD responsive to steroid treatment developed in 3 of 11 allograft recipients. Natural killer (NK) cell function was low before IFN treatment and was not improved with the cytokine. Conversely, interleukin-2-activated NK cells showed normal function even before starting IFN and no change was seen during IFN treatment. Clonogenic hematopoietic progenitor studies showed depression of all progenitor lines (colony-forming unit [CFU]-granulocyte, erythroid, monocyte, megakaryocyte, CFU granulocyte-macrophage, burst-forming unit-erythroid) by IFN at all dose levels except at 0.5 x 10(6) IU/m2. Considering this result and the incidence and severity of marrow depression seen at doses greater than 1.0 x 10(6) IU/m2, we would consider this the maximum dose safely tolerated if IFN alpha-2b is administered in this setting for a prolonged course on a daily basis.
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PMID:Treatment with recombinant interferon (alpha-2b) early after bone marrow transplantation in patients at high risk for relapse [corrected]. 174 91

In an effort to overcome bone marrow failure in myelodysplastic syndrome (MDS), we have investigated recombinant human granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin-3 (IL-3) in phase I-II clinical trials. Although these agents partially increased peripheral blood granulocyte counts, their effect on other hematopoietic lineages was generally sporadic. Since in vitro analysis and in vivo studies in primates indicate that GM-CSF and IL-3 synergistically enhance hematopoietic stem cell proliferation, we evaluated their combined effect on marrow progenitors obtained from ten MDS patients. When used singly, each growth factor stimulated replication of granulocyte-macrophage (CFU-GM) and erythroid (BFU-E) colony-forming cells in a dose-dependent fashion. When colony-stimulating activity was compared at concentrations that maximally amplified individual MDS patients' colony numbers, IL-3 was a more potent stimulant in some patients and GM-CSF in others. When used in combination, IL-3 plus GM-CSF was more effective than each growth factor by itself in five of six patients. Our data indicate that the MDS hematopoietic progenitor stimulatory effect of these growth factors varies from patient to patient. However, the combination of GM-CSF and IL-3 appears to be more potent than the individual molecules in the majority of patients.
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PMID:Granulocyte-macrophage colony-stimulating factor and interleukin-3 in combination: a potent and consistent myelodysplastic syndrome bone marrow stimulant in vitro. 175 90

The in vitro culture growth of marrow granulocyte-macrophage progenitors (CFU-GM assay) was studied in 102 consecutive patients with newly diagnosed primary myelodysplastic syndrome (MDS) to determine its diagnostic utility and prognostic value. There were 18 patients with refractory anemia (RA), eight RA with ringed-sideroblast (RARS), 30 RA with excess of blasts (RAEB), 18 chronic myelomonocytic leukemia (CMML), and 28 RAEB in transformation (RAEB-T). Patients with MDS had a significantly lower number of GM colonies and a significantly higher cluster to colony ratio than those of normal controls and patients with cytopenias of other causes. Six in vitro growth patterns were observed; 85% of patients with MDS showed various abnormal growth patterns, and 42% of all MDS patients exhibited a leukemic growth pattern at diagnosis. None of the 40 patients with cytopenias of other causes had a leukemic type growth. A leukemic growth pattern was rarely observed in patients with RA and RARS (4%), but was common in other subgroups (57%). The distribution of various growth patterns was not statistically different among patients with RAEB, CMML, and RAEB-T. Thirty-six patients developed acute leukemia during the follow-up period. The MDS patients with leukemic type growth were at increased risk of rapid progression to acute leukemia, and they also had a shorter survival time than patients with a non-leukemic pattern. These results showed that simply scoring the number of CFU-GM is of limited value for the diagnosis and the prediction of prognosis of MDS, whereas the in vitro marrow culture growth pattern is of prognostic significance independently of the FAB classification. It is concluded that the in vitro growth pattern of marrow CFU-GM is helpful in diagnosing patients with MDS as well as in predicting their clinical outcome.
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PMID:Diagnostic and prognostic values of in vitro culture growth patterns of marrow granulocyte-macrophage progenitors in patients with myelodysplastic syndrome. 177 58

More than 50% cure can be obtained with allogeneic bone marrow transplantation (BMT) when patients are transplanted in first remission of AML and ALL or chronic phase of CML. On the other hand, considerable progress has been made recently in treating acute leukemia with chemotherapy. Recent studies of intensive chemotherapy in adults with AML report approximately 40-50% 3-year disease-free survival (DFS). Accordingly, several prospective randomized clinical trials have been conducted on the use of BMT versus intensive chemotherapy in the treatment of AML. Significant differences in DFS were found only in a few studies though the results of BMT appear to be comparable or superior to chemotherapy. Therefore, the overall advantage of BMT in first remission AML is smaller than expected. We should know not whether to transplant or to perform chemotherapy, but rather whether to transplant in first remission or to perform chemotherapy first and reserve transplantation as salvage therapy. Recently acute promyelocytic leukemia has been successfully treated with differentiation therapy using all-trans retinoic acid. Low-dose aclarubicin has also been reported to be effective as differentiation therapy in some patients with myelodysplastic syndrome and atypical AML. With the advance of molecular biology of cytokines, several of them are now available for clinical use. G-CSF, GM-CSF and M-CSF are potent stimulators for the granulocyte-macrophage production; they are very effective for accelerating hematologic recovery after chemotherapy-induced myelosuppression or BMT. Interferon-alpha (IFN-alpha) has been used in the several studies. Furthermore, Ph chromosome positivity can be reduced with long-term administration of IFN-alpha; Ph-positive clone can be undetectable in some patients. Thus, IFN-alpha will be the choice of treatment for CML even if BMT is planned.
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PMID:[New trends in the treatment of leukemia]. 177 64

The hematopoietic growth factor interleukin (IL)-3 is a potent regulator of blood cell proliferation. It promotes the survival, proliferation, and development of hematopoietic stem cells and committed progenitor cells of the granulocyte-macrophage, erythrocyte, eosinophil, basophil, megakaryocyte, mast cell, and lymphocyte lineages. In addition, IL-3 enhances mature myeloid cell functions such as phagocytosis and activation of basophils and eosinophils, as well as monocyte cytotoxicity. The first phase of clinical trials suggested that IL-3 may augment myelopoiesis in a number of clinical conditions. It may be efficacious for treatment of primary marrow disorders, including myelodysplastic syndromes and aplastic anemia. However, replacement therapy with IL-3 alone is probably not sufficient to obtain maximal stimulation of myelopoiesis. Preclinical and clinical studies published to date suggest that sequential use or combinations of growth factors will be needed to obtain optimal hematopoietic responses.
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PMID:Interleukin-3. Its biology and potential uses in pediatric hematology/oncology. 178 68

Dexter-type long-term cultures (LTC) were initiated with peripheral blood (PB) and/or bone marrow cells from 11 patients with acute myelogenous leukemia (AML), and 2 with myelodysplastic syndrome in blastic transformation. Marrow and PB cells from normal subjects served as controls. Assessment of nucleated cells and clonogenic progenitors in the adherent and nonadherent fractions of LTC revealed active hemopoiesis for greater than 5 wks in 4 of 8 cultures of AML blood, and 4 of 7 of AML marrow. The morphology and kinetics of nucleated cells and progenitors with putative normal (granulocyte-macrophage colony-forming units or CFU-gm), and abnormal (blast) phenotype in LTC from AML blood were similar to those from AML marrow, and adherent cells positive for collagen I and III and vimentin were found in both types of LTC. Growth of CFU-gm colonies ceased by wk 5-8 in AML cultures, significantly earlier than in LTC of normal marrow cells (survival of greater than 10 wks), which may indicate derivation of the CFU-gm from a transformed clone or deficiency of stromal function in the leukemic state. In most AML blood and AML marrow LTCs, growth of abnormal (blast) colonies continued until wk 4-6. This study demonstrates certain similarities of morphology and function between LTC of AML blood and AML marrow cells. LTC may provide a useful model for further analysis of circulating primitive hemopoietic progenitor cells in leukemic states.
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PMID:Similarities in long-term cultures of blood and bone marrow from patients with acute myelogenous leukemia. 195 36

Daily in situ observation of individual proliferating cells was performed to examine ineffective hemopoiesis in vitro. Bone marrow mononuclear cells (BMMNC) from 24 myelodysplastic syndrome (MDS) patients and 12 controls were cultured for granulocyte-macrophage progenitor (CFU-gm) assays using methylcellulose. Individual proliferating cells were mapped at 3 days of culturing and their fates were followed by daily in situ cell counting contained within each cell aggregate until day 8. By retrospective analysis of the daily growth of the cells, a significantly greater proportion of noncolony-forming cells in MDS were found to proliferate initially, but failed to do so thereafter and degenerated in the culture. Cells showing these abnormal growth characteristics apparently contributed to ineffective granulopoiesis. The present method may be useful for clarifying ineffective granulopoiesis.
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PMID:Ineffective hemopoiesis in the myelodysplastic syndromes (MDS) as studied by daily in situ observation of colony-cluster formation. 195 40


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