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

Bone marrow from patients with acute myelogenous leukemia (AML), acute myelomonocytic leukemia (AMML), chronic myelogenous leukemia (CML), preleukemia, and from healthy volunteers was cultured using a recently developed liquid diffusion technique. Differential and viable cell counts and 3H-thymidine labeling indices were performed at intervals up to 30 days. Differentiation was assessed morphologically by light and electron microscopy, histochemically, and by functional tests for phagocytosis and the presence of surface receptors for IgG. Colony-stimulating activity (CSA) was assayed against normal human bone marrow by the agar colony technique. In acute leukemia cultures, viable cell counts usually fell within the normal range. However, most AML cells failed to demonstrate significant maturation in vitro, and did not produce detectable CSA. In AMML cultures, maturation was defective but some differentiated macrophages were observed and the cells produced high concentrations of CSA. Preleukemic cultures demonstrated normal growth but maturation was impaired as evidenced by a high percentage of immature cells during the first 7 days. CML cultures showed abnormally high growth capacity resulting in viable cell counts 2-3 times normal. In the chronic phase of CML, maturation was qualitatively normal and the cells produced CSA. With the onset of blast transformation, maturation became abnormal but growth remained high. These studies support a concept of AML as a primary defect in cellular maturation and of CML as a primary abnormality of proliferation. The production of CSA by neoplastic cells relates to the degree of monocyte-macrophage differentiation within the leukemic population. Human preleukemia is characterized by a failure of normal maturation in vitro.
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PMID:Proliferation and maturation of human leukemia cells in liquid culture. 105 46

By way of introduction, the physiologic alterations of blood cells in old age are described. Besides the well known anemias in younger persons, protein deficiency may be an additional cause of anemia in the elderly. Acquired sideroblastic anemia of varying etiology is more often seen in the elderly than in younger people. In pernicious anemia the daner of gastric cancer has been overestimated. Aggressive treatment of acute leukemias is not indicated in patients over 60. The special form of smouldering leukemia is mentioned. The syndrome of anemia, thrombocytopenia and enzymatic dysfunction of granulocytes may, it is suggested, be a symptom of preleukemia. Anemia with accelerated sedimentation rate responsive to steriods is helpful in diagnosing polymyalgia rheumatica in the oligosymptomatic form.
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PMID:[Hematological problems in geriatrics]. 105 30

The kinetics of erythropietic and granulocytopoietic cell proliferation have been investigated in the same patient at two distinct stages: firstly in preleukemia presenting as pancytopenia with ineffective erythropoiesis, and secondly 2 years later in acute myelogenous leukemia. The method investigation is based on determining the DNA synthesis rate of individual cells by means of quantitative 14C-autoradiography after short-term incubation with 14C-thymidine and fluorodeoxyuridine. Erythropoiesis was equally ineffective in the two stages, the rate of proliferation, however, slowed down towards the leukemic state. The production rate of myeloblasts was markedly reduced in preleukemia accompained by a very low labelling index. In leukemia on the other hand the production rate was increased to such a degree that the leukemic myeoblast compartment is to be considered as prevailingly self-reproductive. The proliferation rate of myeloblasts was reduced already in preleukemia, and there was a further decrease in leukemia. From the point of view of cell kinetics the manifestation of leukemia in this patient is explained best by a change in the mode of proliferation: the myeloblasts change from steady state growth to behaving like an exponentially expanding population.
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PMID:Proliferation and production of hemopoietic cells two stages of disease: preleukemia and overt leukemia. 106 31

We have previously reported on the ultrastructure of platelets in preleukemia and myelomonocytic leukemia. We referred to an unusual and distinct anomaly of the platelet granules found in 15 of 16 patients. In the present communication we wish to describe and illustrate the light microscopic appearance of giant anomalous granules. Close scrutiny of the platelet morphology and a search for the aforementioned platelet granulopathy are important in the evaluation of patients with myeloproliferative diseases. In this paper we describe and illustrate in more detail the ultrastructure and ultrastructural histochemistry of the abnormal granules. In those patients with the platelet granulopathy, we have conducted in vitro platelet aggregation studies and carried out an electron microscopic evaluation of the aggregates. At least some of the giant granules remained morphologically intact in advanced stages of the aggregation phenomenon, and thus they are probably composed of elements that were not released during aggregation.
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PMID:Platelet granulopathy: a new morphologic feature in preleukemia and myelomonocytic leukemia: light microscopy and ultrastructural morphology and cytochemistry. 106 37

In a combined scanning and transmission electron microscopic study of the red blood cell line in patients with refractory anemia (preleukemia) and myelomonocytic leukemia, certain elements with abundant, convoluted membranes that formed projections over the cell surface were observed. These cells were both normoblasts (nucleated) and reticulocytes (anucleated) and constituted what appeared to be a distinct subpopulation of the red blood cell line. It is possible that in these erythrocytes there is a nucleocytoplasmic asynchronism. We are not certain, however, that they are linked to the leukemic process.
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PMID:The erythrocytic line in refractory anemia (preleukemia or hemopoietic dysplasia) and myelomonocytic leukemia. II. Some unusual morphologic variants of the polychromatic normoblasts and reticulocytes. 106 90

Cytogenetic abnormalities have been found in approximately 50% of all patients with acute leukemia. Although no chromosomal abnormalities have been found which are characteristic of a specific cell type, patients with AML and DiGuglielmo's syndrome more frequently have hypodiploid chromosome numbers, while patients with ALL seldom have hypodiploid numbers of chromosomes and may actually exhibit an extreme degree of hyperdiploidy in the leukemic cells. Chromosome analysis may be helpful in characterizing patients with preleukemia and DiGuglielmo's syndrome, and aneuploidy may correlate with shortened survival in these conditions. Although data so far available are conflicting concerning the relationship of aneuploidy to response to therapy in patients with acute leukemia, it is possible that as improved therapeutic regimens become available for the treatment of acute leukemia, more sophisticated cytogenetic analysis may be helpful in predicting survival and response to therapy.
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PMID:Cytogenetic heterogeneity of the acute leukemias. 106 28

The bone marrow erythrocytic precursors of 12 patients with refractory anemia (preleukemia) or myelomonocytic leukemia were studied by transmission electron microscopy. The results were tabulated in a semiquantitative manner and a comparison was established between the two main diagnostic groups. The following results are reported. 1. Similar nuclear and cytoplasmic abnormalities of the normoblasts were observed in preleukemia and leukemia. 2. A nuclear lesion consisting of nuclear clefts and blebs was demonstrated in at least some of the normoblasts in all of the patients. Although not specific, this finding appears to be a new contribution in the field of preleukemia and myelomonocytic leukemia. 3. Iron overload, including the presence of pathologic sideroblasts, is common to both preleukemia and leukemia.
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PMID:Comparative electron-microscopic study of the erythrocytic line in refractory anemia (preleukemia) and myelomonocytic leukemia. 106 72

In acute myeloid leukemia (AML), many of the remaining normal-appearing cells exhibit various abnormalities. An interpretation is that these cells are descendants of leukemic cells which have succeeded in overcoming the major final differentiation block that exists in AML. Direct evidence is quoted that red cell precursors in AML are of leukemic descent and it is claimed that the target cell of AML is the pluripotent stem cell. Next, evidence has been compiled that all three cell lines (red cell, n. granulocytes, platelets) exhibit qualitative defects in "prelukemia." Hence it is postulated that preleukemia per se doses not exist but that preleukemic states which with a rather high frequency sooner or later end in overt AML are actually true leukemias that, however, differentiate reasonably well. Another way of phrasing it is that preleukemic states are AMLs that present in partial and sometimes long-lasting remission, which only after months to years lose their differentiation ability and then are classified as AML.
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PMID:Preleukemia: does it exist? 106 74

Hemopoietic cell proliferation was studied in a patient suffering from preleukemia characterized by peripheral pancytopenia and hypercellular bone marrow with ineffective erythropoiesis. Two years later when overt acute myelogenous leukemia had developed the study was repeated. The kinetics of proliferation were investigated by a new method which allows evaluation of the rate and time of DNA synthesis in individual morphologically defined cells. Erythropoiesis was found ineffective to the same degree in both stages of disease. The rate of erythroid cell proliferation, however, was reduced in overt leukemia only. The myeloid system showed a grossly reduced production rate of myeloblasts in preleukemia whilst the same parameter was strongly increased in leukemia. This high production rate of myeloblasts in overt leukemia was interpreted as indication of a far-reaching self-maintenance of the myeloblast pool in this stage of disease. The proliferative activity of the individual myeloblasts was reduced already in preleukemia, and even more so in leukemia. In order to explain the amplification of the myeloblast pool with the onset of overt leukemia a change in the mode of myeloblast divisions is assumed. For this a transition from steady state to some degree of exponential growth gives the most plausible explanation.
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PMID:Proliferative behavior of hemopoietic cells in preleukemia and overt leukemia observed in one patient. 107 Apr 63

The results of this study support the concept that the levels of the bifid vertebral arch and of functional motor activity are significant influences on the development of scoliosis and kyphosis in patients born with myelodysplasia. 'Significant' degrees of scoliosis and kyphosis may appear at any time during life, but most frequently occur during late childhood or adolescence. Not all 'significant' curvatures require treatment, nor do all children with myelodysplasia and factors predisposing to kyphosis and scoliosis develop these complications. It is believed that the preliminary cumulative percentage curves presented in this study will be of value in counselling parents of afflicted newborn infants, and in planning the management of patients born with myelodysplasia.
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PMID:Myelodysplasia: the natural history of kyphosis and scoliosis. A preliminary report. 107 Oct 79


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