Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0023467 (acute myeloid leukemia)
 35,200 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The purpose of this paper was to ascertain whether results obtained in cell cultures of AML clonogenic blast cells would provide a useful model for a clinical regimen that combines fludarabine (F-ara-AMP) and cytosine arabinoside (ara-C). In the cultures the nucleoside F-ara-A was used. Blast cells from the continuous lines OCI/AML-2 and OCI/AML-3 were grown, either in methylcellulose to quantify clonogenic cells, or in suspension to measure self-renewal as reflected in changes in numbers of clonogenic cells. F-ara-A, like ara-C, was found to be more toxic to blast stem cells in suspension than in the clonogenic assay, indicating that F-ara-A might, in addition to general cytotoxicity, have some specific inhibitory effects on self-renewing stem cells. F-ara-A was less cytotoxic than ara-C; but, when F-ara-A was given before ara-C, synergism was seen at some F-ara-A doses, as manifested by increased ara-C cytotoxicity. In contrast, when ara-C was given before F-ara-A, protection was observed. Control experiments make it unlikely that this effect is related to changes in the cell cycle following ara-C exposure. We conclude that the cellular studies reported here confirm previous pharmacological data indicating that F-ara-A before ara-C increases the effectiveness of ara-C by increasing the accumulation of ara-CTP. However the present experiments show that the synergism between F-ara-A and ara-C is dependent on both dose and schedule.
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PMID:A cell culture model for the treatment of acute myeloblastic leukemia with fludarabine and cytosine arabinoside. 832 Oct 50

The authors report a de novo AML (M2) patient associated with 5q- as the sole karyotypic abnormality. A 76-year-old woman was referred to our hospital because of anemia and leukocytosis. On examination a neck lymph node was enlarged, but neither the liver nor the spleen could be palpated. The hemoglobin level was 7.1g/dl, the mean corpuscular volume 102fl and the white-cell count was 256.1 x 10(3)/microliters with 87% blast cells. The platelet count was 10.9 x 10(4)/microliters. The bone marrow was hypercellular with 79.8% blast cells and showed dysmegakaryocytopoietic features (hypolobulation, multiple separated nuclei and micromegakaryocytes). Blast cells gave a positive reaction for peroxidase and alpha NB esterase which was not blocked by NaF. The diagnosis of AML (M2) was made but she died before chemotherapy. Autopsy revealed general hemorrhagic tendency and leukemic cell infiltration. Chromosome analysis of the bone marrow showed 46,XX,del(5) (q13q31). Electron micrographs revealed increase of micromegakaryocytes as small as myelocytes and aggregation of demarcation membranes in some megakaryocytes. This may suggest that some molecular changes, instead of karyotypic evolution, contributed to a leukemic transition from the 5q- syndrome to AML with 5q- as the sole abnormality.
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PMID:[Proliferation of micromegakaryocytes in acute myelocytic leukemia associated with 5 q- as the sole karyotypic abnormality]. 851 Mar 36

A specific and quantitative reverse-transcription polymerase chain reaction (RT-PCR) assay was developed for measuring the mRNA of the multidrug resistance-associated protein (MRP). A region corresponding to bp 3897-4471 of MRP cDNA is amplified, which encompasses approximately half of the second nucleotide-binding domain (NBD2). In two multidrug resistant (MDR) sublines of the HL-60 human acute myeloid leukemia (AML) cell line which overexpress MRP but not P-glycoprotein, the assay detects elevated levels of MRP mRNA (4- to 8-fold) relative to the drug-sensitive parental cells (designated HL-60/W). Blast cells from 24 patients with AML were also studied for MRP expression using this RT-PCR method. Expression of MRP was normalized for that of beta-actin in the blast cells, which was also determined by RT-PCR. All of these blast cell samples had MRP expression that was detectable after 35 PCR cycles. Eighteen of these patients samples had levels of expression of MRP mRNA equal to or less than that expressed by HL-60/W cells. In six patient blast cell specimens, the expression of MRP mRNA was up to 1.7-fold higher than that of HL-60/W cells. In 21 specimens, the steady-state intracellular accumulation of daunorubicin (1 microgram/ml, 3h) was also determined. The blast cells with MRP mRNA expression higher than HL-60/W had a lower median accumulation of daunorubicin compared to those whose MRP expression was less than HL-60/W, suggesting a functional defect in drug transport in the cells with higher MRP expression; a similar trend toward lower daunorubicin accumulation was also noted in the one-third of samples that displayed the highest expression of MDR1 mRNA (also determined by RT-PCR). These studies illustrate the range of expression of MRP in AML blast cell specimens. The identification of MRP overexpression in MDR AML cell lines and in some AML patient blast cells with low intracellular daunorubicin accumulation warrants further study of MRP as a component of clinical drug resistance in AML.
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PMID:Expression of multidrug resistance-associated protein (MRP) mRNA in blast cells from acute myeloid leukemia (AML) patients. 855 37

In our efforts to produce monoclonal antibodies that recognize cell-surface antigens expressed by hematopoietic precursor and stromal cells, we generated a monoclonal antibody, 7.1, which recognizes a 220- to 240-kD cell-surface protein whose N-terminal amino acid sequence is identical to the rat NG2 chondroitin sulfate proteoglycan molecule. This chondroitin sulfate proteoglycan, previously reported to be expressed by human melanoma cells, was not found to be expressed by normal hematopoietic cells, nor was it expressed on the cell surface of cell lines of hematopoietic origin including cell lines with 11q23 abnormalities. It was found on the cell surface of acute myeloid leukemia (AML) blasts and cell lines derived from nonhematopoietic tissues. Samples of leukemic marrow from 166 children with AML enrolled on Childrens Cancer Group protocol 213 were evaluated for cell-surface expression of this proteoglycan molecule. In 18 of 166 (11%) patient samples, greater than 25% of leukemic blasts expressed the NG2 molecule. These 18 patients had a poorer outcome with respect to survival (P = .002) and event-free survival (P = .035) with an actuarial survival at 4 years of 16.7%. Blast cell expression of the NG2 molecule was strongly associated with French-American-British M5 morphology (P < .0001) and abnormalities in chromosome band 11q23, site of the MLL gene. These results show that the NG2 molecule is expressed by malignant hematopoietic cells that have abnormalities in chromosome band 11q23, suggesting that antibody 7.1 may be useful in the rapid identification of this group of poor-prognosis patients.
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PMID:The human homologue of rat NG2, a chondroitin sulfate proteoglycan, is not expressed on the cell surface of normal hematopoietic cells but is expressed by acute myeloid leukemia blasts from poor-prognosis patients with abnormalities of chromosome band 11q23. 856 38

There is increasing evidence for an interaction between acute leukemia cells and the microenvironment of the bone marrow. Blast cells from cases of acute myeloid leukemia (AML) and acute lymphoblastic leukemia (ALL) bind to cellular and extracellular matrix components of the bone marrow stroma. In AML, adhesion to stroma is mediated by the combined action of beta 1 (principally VLA-4) and beta 2 integrins, while in precursor-B ALL VLA-4 and VLA-5 integrins play a major role. Adhesion molecules such as CD31, CD44, non-beta 1, beta 2 integrins, growth factor receptors such as c-kit, and other molecules are also likely to play a role. Binding of acute leukemia blasts to ligands on stroma has several pathophysiological consequences. Stromal contact is able to inhibit programmed cell death (apoptosis) in a proportion of cases of both AML and ALL. In ALL, diffusible molecules derived from stroma appear to contribute. Marrow stroma also plays a part in regulating leukemic cell proliferation. While this is partly due to stromal production of hemopoietic growth factors, in soluble or transmembrane form or bound to extracellular matrix, signalling mediated directly by binding of adhesion molecules on leukemic cells may also have a role. Contact of ALL blasts with marrow fibroblasts is followed by migration of leukemic cells, utilizing VLA-4 and VLA-5 integrins, potentially allowing homing of blasts to favourable microenvironmental sites, or controlling egress into the circulation. AML cells compete for stromal binding sites with natural killer cells and cytotoxic lymphocytes, which are known to inhibit their clonogenic growth. We speculate that these complex interactions between leukemic blasts, cellular and matrix components of stroma, and cytotoxic lymphocytes, play a critical role in determining the fate of small numbers of leukemic cells surviving after cytotoxic chemotherapy.
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PMID:Interaction of acute leukemia cells with the bone marrow microenvironment: implications for control of minimal residual disease. 858 Aug 10

Trisomy 13 has been infrequently reported as a primary non-random karyotypic change in myeloid leukemias. To elucidate its clinical significance we examined the clinical and hematological data in nine ANLL patients in whom we found this change, in a series of 175 cytogenetically abnormal ANLL patients. Morphologically, six of the patients were FAB-M1, two were FAB-M4 and one was FAB-M5. Bone marrow aspirates contained more than 90% blasts in eight of the patients. By immunophenotype, TdT was present in four of the patients, CD34 was present in four of five patients tested and CD5 was present in one of five patients tested. Blast cells in all patients expressed two or more myeloid surface antigens. These data suggest the proliferation of an immature myeloid cell in these patients. Complete remission was achieved in seven patients; however, remissions were short-lived. Eight patients expired between 1 and 13 months from diagnosis (median survival 5 months). Combining our findings with data in the published literature on trisomy 13 in ANLL, a larger data set consisting of 29 patients was established to determine better the clinical significance of this cytogenetic entity in ANLL. We found that this cytogenetic change has been reported in all subsets of FAB classification excepting M6 and M7. Median age at presentation was 60 years and no association with gender was noted. Median WBC was 29.5 x 10(9)/l, the majority of patients were thrombocytopenic (median platelet count 86 x 10(9)/l) and median survival was 5.2 months. This study associates trisomy 13 with malignant transformation of myeloid progenitor cells. These patients respond well to induction therapy, but relapse occurs quickly and the survival duration is poor.
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PMID:Clinical and morphological features of cases of trisomy 13 in acute non-lymphocytic leukemia. 861 37

The expression of lymphoid-associated antigens (LAA) on blasts in acute myeloid leukemia (AML) and myeloproliferative disorders in myeloid blast crisis (MPD/MBC) has often been used to establish a diagnosis of acute mixed lineage leukemia (AMLL). The purpose of this study was to determine the incidence of LAA expression in AML and MPD/MBC (Ly + AML); to assess lymphoid differentiation at the genomic level in Ly + AML; and to compare features of Ly + AML with AML and MPD/MBC lacking these antigens (Ly-AML). Seventy-four consecutive cases of AML and MPD/MBC were reviewed for blast morphology, TdT reactivity, and cytochemistry results. Blast immunophenotyping was performed by multiparameter flow cytometry. Acute myeloid leukemia was subtyped according to the FAB classification. Acute myeloid leukemia and MPD/MBC cases expressing one or more of the following antigens, CD2, CD3, CD5, CD7, CD19, or CD20, were considered to be Ly + AML. Immunoglobulin (Ig) and T-cell receptor (TCR) gene rearrangement studies were performed by Southern blot analysis using probes for JH, Jkappa, and JBI/BII. Sixteen of the 74 cases (22%) were identified as Ly + AML. Of these, the T-cell-associated markers CD7, CD2, and CD5 were expressed on 7(44%), 6(38%), and 4(25%) Ly + AML cases, respectively. The B-cell-associated markers CD19 and CD20 were expressed on two cases (13%) and one (6%) case, respectively. The FAB subtypes were similarly represented among Ly + AML and Ly-AML. Expression of LAA did not correlate with TdT positivity. In nine cases of Ly + AML (7 expressing T-cell-associated antigens and two expressing B-cell-associated antigens), Southern blot analysis revealed no Ig or TCR gene rearrangements. These results suggest that expression of CD2, CD5, and CD7 in otherwise straightforward AML should not be taken as evidence of lymphoid lineage commitment and does not warrant a diagnosis of AMLL.
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PMID:Lymphoid-associated antigen expression by acute myeloid leukemia. 871 71

Blast cells derived from patients with acute myelogenous leukemia (AML) were cultured in the presence of interleukin-13 (IL-13). IL-13 did not cause statistically significant alterations of AML blast proliferation when cells were cultured in medium alone or together with IL-4, granulocyte colony-stimulating factor and granulocyte-macrophage colony-stimulating factor. In contrast, IL-13 inhibited constitutive AML blast secretion of IL-1 alpha, IL-1 beta, IL-6, tumor necrosis factor alpha, granulocyte colony-stimulating factor and granulocyte-macrophage colony-stimulating factor. IL-4 caused a similar inhibition of constitutive cytokine secretion as IL-13, but IL-13 caused no additive inhibition in the presence of IL-4. In contrast to IL-4 which increased AML blast release of IL-1 receptor antagonist, IL-13 caused no significant alteration of blast release of the receptor antagonist. IL-13 inhibited cytokine secretion also in the presence of neutralizing IL-4 and IL-10 antibodies and when AML blasts were cultures in serum-free conditions. We conclude that IL-13 has a direct and nontoxic inhibitory effect on constitutive AML blast cytokine secretion.
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PMID:Effects of interleukin-13 on cytokine secretion by human acute myelogenous leukemia blasts. 875 69

In order to establish diagnostic criteria for hypocellular acute leukemia (HL), we have reviewed 32 cases selected on the basis of hypothetical 40% or less cellularity, by focusing on morphology, immunophenotype, karyotype and response to low dose Ara-C (LDAC) regimen and compared them with 40 cases of myelodysplastic syndrome (MDS) and 66 cases of overt acute myeloid leukemia (AML). The onset age ranged from 44 to 75 years (median 67 years). Bone marrow (BM) cellularity ranged from 12.4 to 39.8% (mean 29.8%) in HL, being significantly lower than in MDS (mean 80.7%) or AML (mean 86.4%) (P < 0.001). All reviewed cases characteristically showed smoldering clinical course, bi- or pancytopenia with rare leukemic blasts in the peripheral blood (PB), proliferation of type I leukemic blasts in the BM and markedly reduced background hematopoietic cells with some dysplastic changes in 12/32 cases (37.50/6). Blast percentage (blast %) in the BM ranged from 38.2 to 93.7% (mean 57.3%) in all nucleated cells (ANC). Although a considerable number of cases had blasts with negative or very low myeloperoxidase activity, immunophenotyping revealed that the leukemic blasts in HL had only myeloid markers. Karyotyping revealed non-random chromosome abnormalities in 30% of cases analyzed, which were considerably different from those seen in MDS. With LDAC regimen, a significantly higher CR rate (13/20 cases: 65.0%) was gained in HL than in RAEB/RAEB-t (0%) and overt AML in the elderly cases (27.3%) (P < 0.05). In CR, most cases showed recovery to normocellular BM with an apparent normalization of PB parameters. However, 12 CR cases relapsed 4-12 months later; most of which again showed hypocellular BM. These results indicate that HL is a distinct subtype of AML characterized by slow but distinct proliferation of immature myeloid blasts and by unique hematological features distinct from MDS or overt AML in the elderly. We propose the following diagnostic criteria: (1) pancytopenia with rare appearance of blasts in PB; (2) less than 40% BM hypocellularity; (3) more than 30% blasts in BM-ANC; and (4) myeloid phenotypes of leukemic blasts by MPO staining and/or immunophenotyping.
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PMID:Diagnostic criteria for hypocellular acute leukemia: a clinical entity distinct from overt acute leukemia and myelodysplastic syndrome. 879 90

We examined the multidrug resistance (MDR) P-glycoprotein (P-gp) on normal bone marrow (BM) cells and acute myeloid leukaemia (AML) cells, using newly devised flow cytometric multi-parameter analysis with CD33, CD34 and MRK16 monoclonal antibodies. With biotinylated MRK16 and a Streptavidin-RED670 (SA-RED670) conjugate, we succeeded in the detection of a small amount of P-gp on these cells. In normal bone marrow cells, the percentage of P-gp positive CD34+CD33-, CD34+CD33+ and CD34-CD33+ cells were 12.2 (2.2% (mean +/- standard deviation), 6.3 +/- 3.1% and 1.4 +/- 0.9%, respectively. By the more precise list-mode analysis, myeloid lineage cells showed continuously regressing P-gp expression as they maturated from CD34+CD33- to CD34-CD33+ cells. In AML cells at diagnosis, CD34+ CD33- cells expressed P-gp strongly, CD34+CD33+ cells moderately, and CD34-CD33+ cells weakly, showing the same tendency as observed in normal BM cells. Blast cells from acute promyelocytic leukemia (APL), which mainly expressed CD34-CD33+ but no detectable CD34+CD33- at diagnosis, expressed less amount of P-gp than the other subtypes of AML. P-gp expression on these three phenotypes increased in relapsed cases, especially on the CD34+CD33- subpopulation.
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PMID:[Multidrug resistance in acute leukemia]. 882 70


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