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Query: UMLS:C0026986 (myelodysplastic syndrome)
 14,926 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

As anemia is frequently the main problem in myelodysplastic syndromes (MDS), we studied the efficacy of human erythropoietin (rhEpo) in stimulating the erythroid lineage in 14 patients, starting with 40 U/kg three times a week and doubling the dose every 6 weeks until a response was observed. The highest doses administered were 80 (n = 1), 160 (n = 4), 320 (n = 8) and 640 U/kg (n = 1). One patient (refractory anemia with an excess of blasts, RAEB) showed an increase of hemoglobin, white blood cells and platelets with 80 U/kg rhEpo. However, this patient developed acute leukemia while on therapy. Two other patients (RAEB and RAEB in transformation) also transformed to acute leukemia. In the other 11 patients no response was observed. There was no correlation between in vitro culture data and in vivo responsiveness. The treatment was well tolerated and no nonhematological side effects were observed. From this study we conclude that rhEpo, even when given at high doses, has a low response rate in patients with MDS. Further investigation is needed in order to clarify whether rhEpo increases the potential risk of transformation to acute leukemia.
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PMID:Recombinant human erythropoietin in patients with myelodysplastic syndromes. 203 64

Despite major advances in supportive care, neutropenic infections and thrombopenic bleedings remain major lethal treatment- and disease-related complications in patients with malignancy. Moreover, complications of platelet (Plt) and erythrocyte transfusion therapy have become a cause of great concern and shortages of homologous blood products are a constant problem. Suggestions that the application of recombinant human hemopoietins may provide an alternative treatment modality in this patient population is currently being evaluated in clinical trials. Erythropoietin (EPO) has been shown to be effective in the treatment of anemia in patients with bone marrow, infiltrating low-grade non-Hodgkin's lymphoma, multiple myeloma, and in some patients with myelodysplastic syndrome. Preliminary data suggest that subcutaneous administration of EPO results in a higher slope of increasing erythropoietic parameters compared to intravenous administration. Protective effects on normal erythropoiesis have been attributed to EPO in patients receiving chemotherapy. The finding of EPO receptors on megakaryocytes supports the clinical observation of increased Plt production associated with decreased bleeding and transfusion frequencies in a substantial number of patients receiving EPO. Clinical trials with granulocyte-macrophage (GM-CSF) and granulocyte colony stimulating factor (G-CSF) have reached phase III trials. Both factors show high efficacy to shorten or improve neutropenia related to chemotherapy, bone marrow transplant, or underlying disease. Mechanisms responsible for mucosa protection and improved healing of mucositis observed with both factors remain undetermined yet phase I/II evaluation of IL-3 shows multilineage hemopoietic responses including myeloid, erythroid, and megakaryocyte lineages. Possible anti-cancer effects of hemopoietins achieved by direct action or by increased chemotherapy intensity are currently under investigation.
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PMID:Hemopoietins in clinical oncology. 204 61

Myelodysplasia is an increasingly recognized complication of polycythemia vera (PCV) which often precedes leukemic transformation. This paper describes two patients with aggressive chronic myelomonocytic leukemia, previously undescribed as a complication of PCV. Both patients presented with rapidly increasing splenomegaly which was resistant to treatment with hydroxyurea and external beam irradiation. Splenectomy precipitated fatal hepatic failure in one patient. The other died shortly after transformation to acute myelomonocytic leukemia (FAB M4 classification). Pathology of the bone marrow, spleen, and liver was remarkable for extensive infiltration by dysplastic myeloid elements. Survival was short, only 4-6 months from diagnosis. The unique characteristics in these patients were: (i) prior history of PCV; (ii) rapidly increasing splenomegaly resistant to standard therapy; (iii) absence of overt marrow fibrosis; (iv) hypercellularity (greater than or equal to 90% cellular) of the bone marrow with dysplasia in the myeloid, erythroid, and megakaryocytic cell lines; (v) peripheral monocytosis greater than 1 x 10(9); and (vi) extensive infiltration of the spleen and liver by dysplastic myeloid cells. In addition, the patient who subsequently developed acute leukemia had been treated with hydroxyurea under the PVSG-08 protocol, providing further evidence of the potential leukemogenic effects of this agent.
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PMID:Chronic myelomonocytic leukemia transformation in polycythemia vera. 207 46

For a better understanding of the karyotype evolution of different marrow cell populations in the course of MDS, 6 patients who eventually developed overt leukemia, belonging to a series of 46 MDS referred to our Institution, were studied ad diagnosis and at leukemic progression. In each case the blast cells were separated from the maturing precursors of the erythroid and granulocytic lineage by centrifugation on a Percoll density gradient. Parallel chromosome investigations were performed in each cell fraction. Cytogenetic analysis performed at presentation did not reveal distinctive karyotype features in metaphases arising in the blast enriched cell fraction, as compared with those obtained from the fraction containing erythroblasts and promyelocytes--myelocytes. These findings suggest that in the initial phase of MDS blast cells may lack distinctive cytogenetic features and may thus represent part of a clonal preleukemic proliferation. At the time of leukemia onset, clonal aberrations [trisomy 21 and del(11)(q23)] showing a restricted pattern of distribution within the blast cell enriched fractions were detected in two patients, whereas one patient showed an increase in size of the abnormal clone carrying monosomy 7, an aberration detected in metaphases obtained from both cell fractions. Thus, some evolutive steps in the natural history of these disorders can be heralded by the acquisition of chromosome aberrations more readily detectable in blast enriched cell fractions. In some cases, partial loss of differentiative capability by the abnormal clone may account for the detection, at leukemia onset, of chromosome aberrations involving both the blast cell fraction and the erythroblast-promyelocyte enriched cell fraction.
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PMID:Chromosome studies of enriched blast cell fractions in myelodysplastic syndromes terminating in acute myeloid leukemia. 209 92

Myelodysplastic syndromes (SMD) were studied in 58 patients (37 men, 21 women; mean age 61 years, range 18-81) who were grouped according to FAB criteria (Table 1). None of them showed a secondary SMD to medullary toxic agents or cytostatic treatments although 5 presented concomitant neoplastic disease. Morphologic alterations in peripheral blood smears and bone marrow were registered by 3 hematologists working independently. The intracellular and extracellular iron deposits were evaluated in every case with Perls; peroxidase activity was determined in 16 patients and intraleucocitary alkaline phosphatase reaction was carried out in 17 patients. Twenty five patients (43%) had refractory anemia (RA); 10 (17%) sideroblastic anemia; 13 (25%) refractory anemia with excess of blasts (AREB); 3 (5%) AREB in transformation (AREB-T) and 7 myelomonocytic leukemia (LMMC). Clinical manifestations at diagnosis are described in Table 2. In the observation period there were cases of anemia requiring transfusion, bacterial infections, muco-cutaneous hemorrhage and hemorrhagic episodes in the central nervous system. In the bone marrow smears the cellularity was normal or increased in 53 cases and diminished in only 3. The degree of dysplastic characteristics (erythroid, granulocytic and megakaryocytic) ranged from low to severe. It was low in most of AR, being the erythroid population the most affected in AS and the granulocytic one in AREB and AREB-T. Patients with LMMC showed similar characteristics to those with myeloproliferative syndromes and the differential diagnosis were sometimes difficult, accounting for their separate inclusion in Table 4. Out of 23 patients, 5 presented clonal pathology detected in cytogenetic studies.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Myelodysplastic syndrome: experience of the Study and Treatment of Bone Marrow Failure Group]. 213 Feb 4

An increasing amount of data provides strong evidence for the complex multifactorial control of primary hemopoietic functions. Here we present a new multicellular functional unit, the Hematon, isolated from the light-density floating fraction of normal human bone marrow (BM) aspirates. The Hematon is organized in a compact, three-dimensional spheroid complex from central adipocytes, fibroblastoid cells, and resident macrophages that compartmentalize myeloid, erythroid, and megakaryocyte progenitor cells and their progenies. The Hematon fraction is more than twofold more abundant in progenitor cells when compared to the mononuclear cell (MNC) fraction as gauged by cytological techniques and by analysis of granulocyte-macrophage colony-forming unit (GM-CFU) populations. Individual Hematons may produce, within 2-3 weeks, up to 50,000 hemopoietic cells of different cell lineages in organotypic microcultures. Recombinant human hematopoietic growth factors interleukin 3 (IL-3), granulocyte-macrophage colony-stimulating factor (GM-CSF), granulocyte colony-stimulating factor (G-CSF), and macrophage colony-stimulating factor (M-CSF) significantly stimulated the endogenous cell production of some but not all of the individually treated Hematons, indicating the heterogeneity of factor-responsive cells within the Hematon population. Comparative observations of 184 BM aspirates support the hypothesis that the presence of Hematons in a BM aspirate correlates positively with homeostatic blood cell production, because the Hematon was present in normal BM (31/40) and it was rare among patients with myelodysplastic syndromes (15/53), acute myeloblastic leukemia (7/39), and chronic myelocytic leukemia (5/52). We suggest that the Hematon represents a unifying model around which the variability of fundamental BM functions and dysfunctions can be explored.
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PMID:Hematon, a multicellular functional unit in normal human bone marrow: structural organization, hemopoietic activity, and its relationship to myelodysplasia and myeloid leukemias. 218 30

Monoclonal antibodies (McAbs) against a part of v-myb gene product were prepared for the detection of human c-myb gene product (p75c-myb). Western blotting analyses with these McAbs were performed on human leukemia-lymphoma cells. All T-cell lines were positive in p75c-myb expression. B-cell lines were variable, myeloid and erythroid cells were positive although the amount of expressed p75c-myb was less than the T-cell lines. Cells isolated from patients were positive in expression except for cells from acute myeloblastic leukemia with maturation (AML M2), acute hypergranular promyelocytic leukemia (AML M3) and erythroleukemia (AML M6) developed from myelodysplastic syndromes. Differences in p75c-myb expression seemed to depend upon the differentiation stage and distinctive lineage from which each cell line had been established. The p75c-myb expression in HL60 (acute promyelocytic leukemia cell line) showed remarkably high at logarithmic growth. When examined with HL60, p75c-myb expression significantly decreased during the differentiation induced by 12-O-tetradecanoylphorbol-13-acetate or retinoic acid. These results suggest that p75c-myb expression plays a crucial role in hematopoietic cell proliferation and differentiation and that multiple mechanisms including aberrant expression of p75c-myb is involved in leukemogenesis.
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PMID:p75c-myb expression in leukemia-lymphoma cells correlated with proliferation and differentiation. 218 45

DNA-synthesis rates and concentrations of bone marrow (BM) and peripheral blood (PB) progenitor cells were studied in 22 patients treated with recombinant human interleukin-3 (rhIL3) as part of a clinical phase I/II study. Recombinant hIL3 at doses of 60 to 500 micrograms/m2 was administered by subcutaneous bolus injection for 15 days to 13 patients with solid tumors and preserved hematopoietic function and to nine patients with bone marrow failure, including five with myelodysplastic syndromes. Following treatment with rhIL3, the percentage of actively cycling BM erythroid (BFU-E) and multilineage (CFU-GEMM) progenitors in patients with preserved hematopoietic function increased from 16% to 36% (P less than .05) and from 10% to 40% (P less than .01), respectively. The DNA-synthesis rates of early and late granulocyte macrophage progenitor cells increased from 11% to 26% (CFU-GM day 14; P less than .02) and from 13% to 30% (CFU-GM day 7; P less than .05). There was an increase in BM cellularity from 37% to 58%, and of the myeloid to erythroid ratio from 1.4 to 3.2, while the concentration of marrow progenitors on a per cell basis was unchanged or slightly decreased. The frequencies of blast cells in the BM were unchanged. Mean levels of PB CFU-GM day 14 and CFU-GEMM were 100% and 72% above baseline values after 7 days of rhIL3 but only 25% and 28% above initial levels at the end of treatment. Peripheral blood BFU-E were reduced in the majority of patients with normal marrow after both 7 and 15 days of rhIL3. No augmentation of circulating BFU-E and CFU-GEMM was seen in 5 patients with MDS who had few or no PB BFU-E or CFU-GEMM initially. Total leukocyte, neutrophil, and eosinophil counts increased significantly (P less than .01) in 21 of 22 patients with a peak response after a median of 13 days of rhIL3. While a small increase in reticulocytes was not accompanied by an elevation of the hemoglobin or hematocrit, platelet counts increased by 50% in patients with preserved marrow function. Thus, rhIL3 induces a multilineage response in vivo, apparently by stimulating proliferation of multipotential and lineage-restricted progenitors. It remains to be determined whether this is due to direct or indirect effects on the progenitor cells.
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PMID:Effects of recombinant human interleukin-3 on human hematopoietic progenitor and precursor cells in vivo. 220 25

In vitro colony formation by erythroid progenitors from the bone marrow was studied in 42 patients with a myelodysplastic syndrome using both a standard assay for growing erythroid colonies and an assay designed for growing megakaryocyte colonies. In the standard assay 5 patients had normal numbers of erythroid burst-forming unit (BFU-E) colonies, 8 showed reduced numbers of colonies, and 29 patients had no colony formation. Six patients with markedly reduced numbers of erythroid colonies or no colonies at all in the standard assay showed normal or increased numbers of erythroid colonies in the megakaryocyte assay. In three of these patients the erythroid colony morphology was normal, whereas the other three showed abundant diffuse growth of erythroid subclusters with no normal colonies. In the other patients, the erythroid culture results were similar in both assays. These results indicate that the impairment of erythroid colony growth seen in most patients with a myelodysplastic syndrome is, at least in a number of patients, not due to reduced numbers of erythroid progenitors but to unusual milieu requirements of abnormal progenitors.
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PMID:Effect of culture conditions on in vitro erythroid colony formation in myelodysplastic syndromes. 220 60

A high remission rate (75%) was achieved in a preliminary study using bestatin in patients with refractory anemia with excess blasts (RAEB) and RAEB in transformation (RAEB-t). One of 2 patients with RAEB-t and 3 of 6 patients with RAEB obtained complete response. Two patients with RAEB achieved good response, but one with refractory anemia failed. Clonogenic marrow cell culture studies in patients with myelodysplastic syndromes have demonstrated intrinsic hematopoietic stem cell abnormalities, in particular defective erythroid colony formation. After bestatin treatment, these abnormalities as well as hematologic findings were markedly improved. The results suggest that bestatin has an enhancing effect on burst promoting activity production of helper (CD4 positive) T lymphocytes and the effect on hematopoiesis of bestatin may be mediated by T lymphocytes.
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PMID:Bestatin treatment of myelodysplastic syndromes (MDS) and the effects of bestatin on hematopoiesis in MDS. 222 53


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