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)

We have tried to improve existing methods for demonstration of platelet peroxidase (PPO) in human platelets and megakaryocytes by introducing a fixation of 0.1% glutaraldehyde prior to incubation in the DAB medium. This prefixation with low concentration of glutaraldehyde preserves excellent morphological detail and does not inhibit PPO activity. All 23 platelet-rich plasma samples show PPO reaction product in the dense tubular system after incubation in DAB medium with 0.003% H2O2. When 0.01% H2O2 is used in excessive DAB medium, PPO activity can also be demonstrated in platelets and megakaryocytes of bone-marrow cell suspensions. This method can be used for the identification of megakaryoblasts in acute non-lymphocytic leukemia, myelodysplastic syndromes and in blastic crisis of chronic myeloid leukemia. PPO cytochemistry can be combined with postfixation in a OsO4-ruthenium red mixture. This method reveals alpha-granules, dense bodies, microtubuli, glycogen, mitochondria, dense tubular system and invaginated membrane system in the same platelet and is useful for investigation of platelet ultrastructure.
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PMID:A reliable method with good cell preservation for the demonstration of peroxidase activity in human platelets and megakaryocytes. 619 33

We analyzed active oxygen (hydroperoxide; H2O2) production by peripheral neutrophils in various hematological diseases by flow cytometry. One hundred microliters of heparinized fresh blood was sequentially incubated at 37 degrees C with 2',7'-dichlorofluorescein diacetate and with or without phorbol myristate acetate (PMA). After hemolysis, the pelleted white blood cells were subjected to flow cytometry, and the neutrophil fraction was gated on the cytogram. Production of H2O2 by the fraction was estimated by determining the increase in the relative intensity of fluorescence emitted from the fraction in response to stimulation by PMA. In controlled chronic myelogenous leukemia (CML) (WBC < 1 x 10(10)/1), H2O2 production was normal, while in uncontrolled CML (WBC > or = 1 x 10(10)/1), it was reduced. In myelodysplastic syndrome (MDS), H2O2 production was also reduced, but no significant difference was observed among FAB classification disease types in MDS patients. In untreated acute non-lymphocytic leukemia (ANLL), H2O2 production was reduced, while in the complete remission stage of ANLL, its level was normal, suggesting recovery from normal clones. In aplastic anemia, the H2O2 production level was normal. Steroid therapy might be responsible for the reduction of H2O2 production in non-Hodgkin's lymphoma and multiple myeloma. The production of H2O2 is closely related to the oxygen-dependent bactericidal activity of neutrophils, and, hence, can be utilized as an index to indicate susceptibility to infection. This neutrophil function can be determined easily in ordinary clinical facilities by using flow cytometry, and care should be taken to prevent infection when H2O2 production is reduced.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Flow cytometric determination of active oxygen (hydroperoxide) produced by peripheral blood neutrophils in patients with hematological disorders. 836 85

Vitamin K2 (VK2) effectively induces apoptosis in leukemia cell lines, including HL-60 and U937. However, combined treatment of cells with VK2 plus 1alpha,25-dihydroxy vitamin D3 (VD3) resulted in suppression of VK2-inducing apoptosis and pronounced induction of monocytic differentiation as compared with that by VD3 alone. After achieving monocytic differentiation by pre-exposure to VK2 and VD3, the cells became resistant to various apoptotic stimuli including VK2- and H2O2-treatment and serum deprivation. Accumulation of cytoplasm p21CIP1 along with disappearance of nuclear p21CIP1 was detected in cells in response to 96-h treatment with VK2 plus VD3. A stable transfectant, U937-deltaNLS-p21CIP1, which lacked the nuclear localization signal of p21CIP1 and showed overexpression of cytoplasm p21CIP1 without monocytic differentiation, was resistant to apoptosis. These data suggest that a change of intracellular distribution of p21CIP1 from nucleus to cytoplasm along with differentiation appears to be anti-apoptotic. Clinical benefits of using VK2 for treatment of patients with leukemia and myelodysplastic syndrome (MDS) have been reported. Our data suggest that VK2 plus VD3 may be an effective combination for differentiation-based therapy for leukemia and also MDS whose cytopenias are mediated though apoptosis.
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PMID:Combined treatment of leukemia cells with vitamin K2 and 1alpha,25-dihydroxy vitamin D3 enhances monocytic differentiation along with becoming resistant to apoptosis by induction of cytoplasmic p21CIP1. 1614 3

Myelodysplastic syndromes (MDS) are a heterogeneous group of clonal stem cell disorders with an inherent tendency for transformation in secondary acute myeloid leukemia. This study focused on the redox metabolism of bone marrow (BM) cells from 97 patients compared with 25 healthy controls. The level of reactive oxygen species (ROS) was quantified by flow cytometry in BM cell subsets as well as the expression level of 28 transcripts encoding for major enzymes involved in the antioxidant cellular response. Our results highlight increased ROS levels in BM nonlymphoid cells and especially in primitive CD34posCD38low progenitor cells. Moreover, we identified a specific antioxidant signature, dubbed "antioxidogram," for the different MDS subgroups or secondary acute myeloblastic leukemia (sAML). Our results suggest that progression from MDS toward sAML could be characterized by 3 successive molecular steps: (1) overexpression of enzymes reducing proteic disulfide bonds (MDS with <5% BM blasts [GLRX family]); (2) increased expression of enzymes detoxifying H2O2 (MDS with 5% to 19% BM blasts [PRDX and GPX families]); and finally (3) decreased expression of these enzymes in sAML. The antioxidant score (AO-Score) defined by logistic regression from the expression levels of transcripts made it possible to stage disease progression and, interestingly, this AO-Score was independent of the revised International Scoring System. Altogether, this study demonstrates that MDS and sAML present an important disturbance of redox metabolism, especially in BM stem and progenitor cells and that the specific molecular antioxidant response parameters (antioxidogram, AO-Score) could be considered as useful biomarkers for disease diagnosis and follow-up.
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PMID:Bone marrow oxidative stress and specific antioxidant signatures in myelodysplastic syndromes. 3186 14