Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.3.1 (alkaline phosphatase)
 47,916 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

It has previously been shown that patients with aplastic anemia (AA) have a stem cell defect both of proliferation and differentiation. This has been shown by long-term bone marrow (BM) culture, long-term initiating cell assays, and committed progenitor assays. We present, for the first time, data on megakaryocyte (Mk) colony formation from purified BM CD34(+) cells from patients with AA. The results are compared with those from normal controls and from patients with paroxysmal nocturnal hemoglobinuria (PNH) and the myelodysplastic syndromes (MDSs). Those treated for AA had previously received immunosuppression (antithymocyte globulin and/or cyclosporin). No patients had received bone marrow transplantation. A total of 13 AA patients (five untreated, eight treated), six PNH, six MDS, and 13 normal donors were studied. BM CD34(+) cells were purified by indirect labeling and then cultured in a collagen-based Mk assay kit (MegaCult-C, StemCell Technologies). The cultures were fixed on day 12, and the Mk colonies were identified by the alkaline phosphatase anti-alkaline phosphatase technique using the monoclonal antibody CD41 (GP IIb/IIIa). The slides were scored for Mk colony-forming units (CFU-Mks) (3-20 and >20 cells), Mk burst-forming units (BFU-Mks) (>50 cells), and mixed colonies. The results show that total Mk colony formation in AA was significantly lower than in normal donors (p<0.0001), both in untreated patients/nonresponders to treatment (p = 0.0001) and in complete/partial responders (p<0.002). There was no significant difference in Mk colony formation in treated and untreated patients (p = 0.05). Patients with AA had a lower total colony formation than PNH patients (p = 0.0002). PNH patients exhibited lower colony formation than normal controls (p = 0.03), as shown by MDS patients, although the considerable number of variables resulted in a lack of statistically significant difference from normal controls (p = 0.2). We have now shown that Mk colony formation from purified BM CD34(+) cells is significantly reduced, supporting previous evidence that AA results from a stem cell defect.
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PMID:In vitro proliferation and differentiation of megakaryocytic progenitors in patients with aplastic anemia, paroxysmal nocturnal hemoglobinuria, and the myelodysplastic syndromes. 1107 31

Paroxysmal nocturnal hemoglobinuria (PNH) is an uncommon acquired stem cell disorder associated with periodic hemolytic events. This benign clonal disease is caused by abnormalities of the X-linked phosphatidylinositol glycan class A (PIGA) gene and is associated with cytopenias and thrombosis. Although the trilineage of bone marrow elements is affected, involvement of the red blood cell (RBC) line was recognized first due to its abnormal sensitivity to complement-mediated intravascular hemolysis. Totally or partially deficient blood cell membrane proteins include decay accelerating factor (DAF, CD55), membrane inhibitor of reactive lysis (MIRL, CD59), and other proteins attached to the glycophosphatidylinositol (GPI) spine. Stem cell transplantation can be curative in PNH. Diverse laboratory abnormalities observed in PNH include bone marrow hyper- and hypoplasia, hematologic cytopenias, micro- and macrocytosis, decreased leukocyte alkaline phosphatase (LAP), hemoglobin- and hemosiderinuria, as well as associated iron deficiency. The more definitive laboratory tests comprise older biochemical and newer flow cytometric (FCM) procedures. The former group includes the sucrose hemolysis test for screening and Ham's acid hemolysis test for confirmation; the latter group includes FCM analyses of CD55 and CD59, which have recently replaced Ham's test, and FCM quantification of specific GPI-anchor binding using fluorescent-labeled inactive toxin aerolysin (FLAER). FLAER is more sensitive than FCM quantification of antibody-binding to CD59 for PNH diagnosis.
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PMID:Laboratory diagnosis of paroxysmal nocturnal hemoglobinuria. 1458 53

Paroxysmal nocturnal hemoglobinuria (PNH) clones deficient in glycosylphosphatidylinositol-anchored molecules, including CD55 and CD59, have been previously described in patients with multiple myeloma (MM). The aim of this study was to investigate the possible association between existence of the PNH phenotype and myeloma bone disease. Forty-three patients with newly diagnosed MM were the subjects of the study. Radiographic evaluation of the skeleton was performed in all patients at diagnosis. The following biochemical markers were measured: bone resorption markers (tartrate-resistant acid phosphatase isoform 5b [TRACP-5b]and N-terminal cross-linking telopeptide of type-I collagen [NTX]), bone formation markers (bone alkaline phosphatase [bALP] and osteocalcin [OC]), osteoprotegerin (OPG), soluble receptor activator of nuclear factor KB ligand (sRANKL), and interleukin 6 (IL-6). Detection of CD55- and/or CD59-deficient red cell populations was performed after diagnosis. Patients with MM had elevated mean baseline NTX, TRACP-5b, sRANKL, and IL-6 levels compared with controls, whereas the mean values of bALP, OC, and OPG were significantly decreased. Four patients had no osteolytic lesions, whereas 8 patients had 1 to 3 lytic lesions, and 31 patients had more than 3 lytic lesions and/or pathologic fractures in the skeletal survey. CD55- and/or CD59-deficient red cell populations were observed in 56% of patients with MM. There was a strong correlation between the presence of PNH-like erythrocytes and increased bone resorption, as measured by NTX, TRACP-5b, and sRANKL/OPG ratio (P < .03, P < .02, and P < .02, respectively). There was also a significant correlation between PNH phenotype and severe bone disease (P < .02). These results suggest that there is a possible link between PNH phenotype and increased osteoclastic activity in MM owing to a potential effect of myeloma microenvironment on a preexisting PNH clone. Further studies are required for clarifying this phenomenon and investigating possible mechanisms of this unusual association.
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PMID:Unusual association between increased bone resorption and presence of paroxysmal nocturnal hemoglobinuria phenotype in multiple myeloma. 1468 93


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