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 appearance of chemoresistance is the most relevant limitation of chemotherapy. It has been shown that multidrug resistance (MDR) is frequently related to the expression of a membrane glycoprotein (P-170). This protein is able to bind ATP and leads to decreased accumulation of structurally unrelated antineoplastic drugs extensively used in the management of hematological patients. The availability of monoclonal antibodies and probes allowed extensive studies both "in vitro" and "in vivo" of the protein structure and of its mechanism of action. The P 170 activity may be antagonized by drugs able to compete with chemotherapic agents for the binding or by calcium antagonists that inhibit the expulsion activity of the protein. P 170 has been found in variable percentages of several hematological malignancies such as leukemia, myelodysplastic syndromes, myeloma and lymphoma. The reported data seem to indicate that the patients carrying P 170-positive neoplastic cells should be treated with drugs that are not bound by the protein. However, the possibility of inhibiting the protein function and the recent reports suggesting the use of P 170 as a target for immunotoxins could be the basis for new therapeutic protocols.
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PMID:Multidrug resistance: focus in hematology. 198 Apr 79

Platelet membrane glycoproteins were analyzed in a case of myelodysplastic syndrome with inv(3) (q21q26) presenting with prominent dysmegakaryopoiesis by three different labelling techniques for surface proteins. Markedly decreased level of platelet membrane glycoprotein GPIIb was observed in the patient's platelets by terminal sialic acid labelling method, whereas no significant changes in the levels of glycoproteins including GPIIb could be detected either by penultimate galactose labelling or by tyrosine/histidine labelling. These results indicate a decreased sialylation of GPIIb in the patient's platelets, implying aberrant process in thrombopoiesis in the disease.
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PMID:Abnormality of platelet membrane glycoprotein GPIIb in a myelodysplastic syndrome with 3q inversion presenting with marked dysmegakaryopoiesis. 210 94

Bernard-Soulier syndrome is an inherited bleeding abnormality characterized by thrombocytopenia with large platelets and deficiency of the platelet membrane glycoprotein (GP) Ib-IX complex. We have identified a young female with an acquired Bernard-Soulier-like platelet defect and a coexisting primary myelodysplastic disorder. Abnormal bruising had developed at age 5. A normal platelet count with some giant platelets was noted at age 7. At age 9 she developed a large haematoma following surgery. Laboratory investigation revealed thrombocytopenia and large platelets. Platelet membrane glycoprotein analysis showed a marked deficiency of the components of the GP Ib-IX complex (approximately equal to 25% of normal). Flow cytometry revealed two populations of platelets: a predominant population of large platelets lacking the GP Ib-IX complex and a minor population of normal-sized platelets with normal GP Ib-IX expression. The patient developed progressive anaemia, more severe thrombocytopenia and neutropenia, and circulating blast cells were seen. A bone marrow showed gross hypercellularity with marked dysplasia of all three lineages and increased blasts. Marrow cytogenetic studies showed the presence of monosomy 7 in all metaphases, with an additional trisomy 21 in 10%. Peripheral blood cells were normal 46XX. The above data are consistent with an acquired myelodysplastic syndrome associated with a Bernard-Soulier-like platelet defect.
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PMID:An acquired Bernard-Soulier-like platelet defect associated with juvenile myelodysplastic syndrome. 334 99

To aid in the rapid differential diagnosis of thrombocytopenia, the authors developed a latex agglutination test for glycocalicin, a proteolytic fragment of platelet membrane glycoprotein Ib. Plasma glycocalicin determinations were performed for 34 patients with thrombocytopenia. Plasma samples from four patients with aplastic anemia and ten patients with myelodysplastic syndromes, all with glycocalicin levels less than 0.6 mg/L by an enzyme-linked immunosorbent assay, all had negative results by the latex test. In contrast, positive latex agglutination titers were obtained for all 12 patients with idiopathic thrombocytopenic purpura. Eight patients with liver cirrhosis and splenomegaly had elevated levels of plasma glycocalicin, and all of their plasma samples produced agglutination. This latex agglutination test for glycocalicin allows a rapid discrimination of thrombocytopenia caused by impaired platelet production from that caused by increased platelet destruction; thus, it is suitable for use as a screening test in a routine clinical laboratory.
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PMID:Rapid detection of plasma glycocalicin by a latex agglutination test. A useful adjunct in the differential diagnosis of thrombocytopenia. 824 98

In myelodysplastic syndromes (MDS), dysplastic changes in neutrophils are a common feature reflecting the total degree of bone marrow dysplasia. Furthermore, granulocyte function is abnormal, so that a high risk of life-threatening infections has been documented. In this review we shall focus on the defects of both granulocytes and their CD11b/CD18 glycoprotein complex, which regulate granulocyte adherence, locomotion, diapedesis and migration into inflammatory sites, in patients suffering from primary MDS. The defective surface membrane glycoprotein expression of myelodysplastic phagocytes is not only a useful diagnostic tool, but also a powerful prognostic one, since MDS patients with such defects present both an increased susceptibility to infections and a decreased survival. Moreover, the administration of colony-stimulating factors is known to be able to elicit long-lasting improvement in neutrophil count, CD11b/CD18 expression and function, marrow myeloid maturation, and possibly to decrease bacterial infections in MDS patients.
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PMID:Granulocyte dysplasia and dysfunction, and CD11/CD18 defects in myelodysplastic syndromes. 903 Nov 7

The hemorrhagic and thrombotic diathesis represents a frequent complication in myelodysplastic syndromes (MDS) and in acute leukemias. They are correlated with the number of the platelets, but also with their qualitative disorders, such as membrane glycoprotein changes. The latter are revealed by many platelet studies including flow-cytometry and comprise modified activation, secretion and aggregation patterns.
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PMID:Platelet dysfunction in acute leukemias and myelodysplastic syndromes. 2202 58