Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.7.10.1 (ERK)
 95,504 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Endothelial precursor cells (EPCs) have been identified in adult peripheral blood. We examined whether EPCs could be isolated from umbilical cord blood, a rich source for hematopoietic progenitors, and whether in vivo transplantation of EPCs could modulate postnatal neovascularization. Numerous cell clusters, spindle-shaped and attaching (AT) cells, and cord-like structures developed from culture of cord blood mononuclear cells (MNCs). Fluorescence-trace experiments revealed that cell clusters, AT cells, and cord-like structures predominantly were derived from CD34-positive MNCs (MNC(CD34+)). AT cells and cell clusters could be generated more efficiently from cord blood MNCs than from adult peripheral blood MNCs. AT cells incorporated acetylated-LDL, released nitric oxide, and expressed KDR, VE-cadherin, CD31, and von Willebrand factor but not CD45. Locally transplanted AT cells survived and participated in capillary networks in the ischemic tissues of immunodeficient nude rats in vivo. AT cells thus had multiple endothelial phenotypes and were defined as a major population of EPCs. Furthermore, laser Doppler and immunohistochemical analyses revealed that EPC transplantation quantitatively augmented neovascularization and blood flow in the ischemic hindlimb. In conclusion, umbilical cord blood is a valuable source of EPCs, and transplantation of cord blood-derived EPCs represents a promising strategy for modulating postnatal neovascularization.
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PMID:Transplanted cord blood-derived endothelial precursor cells augment postnatal neovascularization. 1084 11

The t(12;21)(p13;q22) fusion gene is the most frequent genetic lesion described in precursor B cell acute lymphoblastic leukemia (ALL) of childhood occurring in a quarter of cases. This gene rearrangement is associated with a good outcome presenting a high response rate to chemotherapy. In spite of its potential clinical relevance, the t(12;21) translocation usually goes undetected with conventional cytogenetic procedures. In the present study we utilized an objective flow cytometric approach (multiparametric quantitative analysis) for the phenotypic characterization of this type of ALL. We studied a total of 74 precursor B-ALL children, including 21 t(12;21)+ and 53 t(12;21)- cases. Our results show that the t(12;21)(p13;q22)+ ALLs display a higher intensity of CD10 (P = 0.0016) and HLADR (P = 0.005) expression together with lower levels of the CD20 (P = 0.01), CD45 (P = 0.01), CD135 (P = 0.003) and CD34 (P = 0.03) antigens as compared to the t(12;21) cases. Moreover, as regards CD34 expression, we observed a more heterogeneous antigen expression within individual patients with higher coefficients of variation (median of 202 vs 88, P = 0.0001). A multi-variate analysis disclosed that with the immunophenotypic approach used identification of t(12;21)+ cases can be achieved with a sensitivity of 86% and a specificity of 100%. We conclude that childhood precursor B-ALL carrying the t(12;21) translocation display characteristic phenotypic features which could provide a rapid, simple, sensitive and specific screening method to select for those cases that should undergo confirmatory molecular analysis.
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PMID:Quantitative multiparametric immunophenotyping in acute lymphoblastic leukemia: correlation with specific genotype. I. ETV6/AML1 ALLs identification. 1091 46

Several recent studies suggest the isolation of stem cells in skeletal muscle, but the functional properties of these muscle-derived stem cells is still unclear. In the present study, we report the purification of muscle-derived stem cells from the mdx mouse, an animal model for Duchenne muscular dystrophy. We show that enrichment of desmin(+) cells using the preplate technique from mouse primary muscle cell culture also enriches a cell population expressing CD34 and Bcl-2. The CD34(+) cells and Bcl-2(+) cells were found to reside within the basal lamina, where satellite cells are normally found. Clonal isolation and characterization from this CD34(+)Bcl-2(+) enriched population yielded a putative muscle-derived stem cell, mc13, that is capable of differentiating into both myogenic and osteogenic lineage in vitro and in vivo. The mc13 cells are c-kit and CD45 negative and express: desmin, c-met and MNF, three markers expressed in early myogenic progenitors; Flk-1, a mouse homologue of KDR recently identified in humans as a key marker in hematopoietic cells with stem cell-like characteristics; and Sca-1, a marker for both skeletal muscle and hematopoietic stem cells. Intramuscular, and more importantly, intravenous injection of mc13 cells result in muscle regeneration and partial restoration of dystrophin in mdx mice. Transplantation of mc13 cells engineered to secrete osteogenic protein differentiate in osteogenic lineage and accelerate healing of a skull defect in SCID mice. Taken together, these results suggest the isolation of a population of muscle-derived stem cells capable of improving both muscle regeneration and bone healing.
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PMID:Clonal isolation of muscle-derived cells capable of enhancing muscle regeneration and bone healing. 1097 97

By using ligands with various affinities for the T-cell receptor (TCR) and by altering the contribution of the CD45 tyrosine phosphatase, the effects of the potency of TCR-induced signals on the function of small GTPases Ras and Rap1 were studied. T cells expressing low-molecular-weight CD45 isoforms (e.g., CD45RO) exhibited the strongest activation of the Ras-dependent Elk-1 transcription factor and the highest sensitivity to the inhibitory action of dominant negative mutant Ras compared to T cells expressing high-molecular-weight CD45 isoforms (ABC). Moreover, stimulation of CD45RO(+), but not CD45ABC(+), T cells with a high-affinity TCR ligand induced suboptimal Elk-1 activation compared with the stimulation induced by an intermediate-affinity TCR-ligand interaction. This observation suggested that the Ras-dependent signaling pathway is safeguarded in CD45RO(+) expressors by a negative regulatory mechanism(s) which prohibits maximal activation of the Ras-dependent signaling events following high-avidity TCR-ligand engagement. Interestingly, the biochemical activity of another small GTPase, the Ras-like protein Rap1, which has been implicated in the functional suppression of Ras signaling, was inversely correlated with the extent of Elk-1 activation induced by different-affinity TCR ligands. Consistently, overexpression of putative Rap dominant negative mutant RapN17 or the physiologic inhibitor of Rap1, the Rap GTPase-activating protein RapGAP, augmented the Elk-1 response in CD45RO(+) T cells. This is in contrast to the suppressive effect of RapN17 and RapGAP on CD45ABC(+) T cells, underscoring the possibility that Rap1 can act as either a repressor or a potentiator of Ras effector signals, depending on CD45 isoform expression. These observations suggest that cells expressing distinct isoforms of CD45 employ different signal transduction schemes to optimize Ras-mediated signal transduction in activated T lymphocytes.
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PMID:Combinatorial effect of T-cell receptor ligation and CD45 isoform expression on the signaling contribution of the small GTPases Ras and Rap1. 1107 75

The expression of myelomonocytic-associated antigens in anaplastic large cell lymphomas (ALCLs), particularly those presenting in extranodal sites, can make their distinction from extramedullary myeloid cell tumors (EMCTs) or histiocytic tumors problematic. Yet, this distinction is clinically significant because of its therapeutic and prognostic implications. Herein, we describe a case of extranodal anaplastic lymphoma kinase-positive CD30-positive ALCL of T-cell origin in a 12-year-old boy, which was initially called an EMCT because of the expression of CD13 and HLA-DR detected by flow cytometry and the absence of other T-cell-related surface markers. However, the detection of cytoplasmic CD3 by flow cytometry prompted further studies. The tumor was composed of large cells with abundant slightly eosinophilic vacuolated cytoplasm and ovoid or reniform nuclei with a few small nucleoli. Using immunohistochemistry, the tumor was positive for CD45, CD30, CD45RO, and CD43 with a strong cytoplasmic and nuclear anaplastic lymphoma kinase stain. The tumor cells showed a T-cell clonal genotype. Electron microscopy revealed no ultrastructural features of myelomonocytic or histiocytic origin. The patient responded well to the chemotherapy and was in complete remission for 10 months at the time of submission of this manuscript. Review of the literature showed inconsistencies regarding the diagnosis, nomenclature, and, therefore, treatment and prognosis of these tumors. In addition, the CD13 expression in ALCL raises some histogenetic questions and may indicate origin from a pluripotent stem cell, misprogramming during malignant transformation, or a microenvironmental effect on lymphoid cell expression of surface antigens. Therefore, ALCL should be considered in the differential diagnosis of EMCTs or histiocytic tumors, particularly when surface marker lineage assignment is ambiguous.
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PMID:CD13-positive anaplastic large cell lymphoma of T-cell origin--a diagnostic and histogenetic problem. 1110 61

CD13 is commonly expressed in hematopoietic malignancies of myelomonocytic origin and has less commonly been described in lymphoid neoplasms, including acute lymphoblastic leukemia, B-cell lymphoproliferative disorders, and plasma cell malignancies. Aberrant CD13 expression has rarely been described in KP-1 (CD68)-positive large-cell lymphomas. However, CD13 positivity has not previously been described in a case of CD30+ (ALK-1+) anaplastic large-cell lymphoma of presumed null-cell origin without histiocytic differentiation. The purpose of this case report is to describe a CD30+ anaplastic large-cell lymphoma of presumed null-cell origin with aberrant expression of CD13. The case illustrates the unique usefulness of immunophenotypic and molecular techniques in establishing the correct diagnosis. The case was referred with a diagnosis of "rule out granulocytic sarcoma versus megakaryocytic malignancy" due to the morphology and a limited flow cytometric immunophenotypic (FCI) panel that had been performed and revealed expression of CD45, HLA-DR, and CD13. Subsequent morphologic review at our institution combined with an expanded FCI panel established the diagnosis. The differential diagnosis of a CD13+ hematopoietic malignancy should include this entity. The prognostic significance of this finding has yet to be determined.
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PMID:CD30+ anaplastic large-cell lymphoma with aberrant expression of CD13: case report and review of the literature. 1113 13

Identification of culture conditions that support expansion or even long-term maintenance of in vivo repopulating human hematopoietic stem cells is still a major challenge. Using a combination of FLT3 ligand (FL), Stem Cell Factor (SCF), Thrombopoietin (TPO) and Interleukin 6 (IL6), we cultured cord blood (CB) CD34+ cells for up to 12 weeks and transplanted their progeny into sublethally irradiated NOD/SCID mice. Bone marrow engraftment was considered successful when recipients contained measurable numbers of human CD45+, CD71+ and Glycophorin A+(GpA) cells 8 weeks after transplantation. Twelve-week expanded cells with FL+SCF+TPO+IL6 successfully engrafted all of the recipients and human CD45(+)+CD71(+)+GpA(+) cells represented 4.3 to 22.4% of bone marrow. Substitution of IL6 with IL3 led to an even better expansion of cells and a similar clonogenic progenitor output in the first 8 weeks of culture; however, LTC-IC output increased up to week 6 and then decreased and disappeared. By contrast, with FL+SCF+TPO+IL6, LTC-IC kept increasing up to week 12. Four-week cultured cells with FL+SCF+TPO+IL3 less efficiently engrafted NOD/SCID mice, both as measured by frequency of positive recipients (4 out of 10) and percentage of engrafted human cells (< or =2%). Six-week expanded cells failed to engraft. This study provides evidence that many, but not all, of the so-called "early acting" cytokines, can sustain long-term maintenance and even expansion of human primitive in vivo repopulating stem cells. In particular, in the culture conditions used in this study, the presence of IL3 greatly reduces the repopulating potential of expanded CD34+ CB cells.
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PMID:Negative influence of IL3 on the expansion of human cord blood in vivo long-term repopulating stem cells. 1117 9

Primary effusion lymphoma (PEL) has been recognized as a body-cavity-based lymphoma that was originally reported to be associated with human herpes virus 8 (HHV8) infection, and was frequently found in human immunodeficiency virus-positive (HIV) patients. Here we describe an autopsy case of PEL of the peritoneal cavity in an immunocompetent patient. Cytological analysis of tumor cells within ascites revealed immunocytochemical features of keratin positivity and CD45 negativity. At autopsy, the presence of a massive volume of ascites as well as diffuse tumor cell infiltrates within the serosa of the intestine and mesenterium were observed. Tumor cells were morphologically similar to anaplastic large-cell lymphoma, but were immunohistochemically positive for keratin and epithelial membrane antigen (EMA). They also showed no reactivity to representative lymphocyte surface markers including CD45, in addition to being negative for CD30 and p80NPM/ALK. Molecular analysis of the tumor cells revealed monoclonality of the immunoglobulin heavy-chain gene rearrangement which demonstrated a lymphoma of the B-cell lineage. Furthermore, HHV8 was not detected by immunohistochemical analysis, PCR or nested PCR technique. Based on these results, we consider the present case to be an HHV8-negative PEL with keratin and EMA positivity.
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PMID:HHV8-negative primary effusion lymphoma of the peritoneal cavity presenting with a distinct immunohistochemical phenotype. 1135 Jun 13

We report a method of purifying, characterizing and expanding endothelial cells (ECs) derived from CD133(+) bone marrow cells, a subset of CD34(+) haematopoietic progenitors. Isolated using immunomagnetic sorting (mean purity 90 +/- 5%), the CD133(+) bone marrow cells were grown on fibronectin-coated flasks in M199 medium supplemented with fetal bovine serum (FBS), vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF) and insulin growth factor (IGF-1). The CD133(+) fraction contained 95 +/- 4% CD34(+) cells, 3 +/- 2% cells expressing VEGF receptor (VEGFR-2/KDR), but did not express von Willebrand factor (VWF), VE-cadherin, P1H12 or TE-7. After 3 weeks of culture, the cells formed a monolayer with a typical EC morphology and expanded 11 +/- 5 times. The cells were further purified using Ulex europaeus agglutinin-1 (UEA-1)-fluorescein isothiocyanate (FITC) and anti-FITC microbeads, and expanded with VEGF for a further 3 weeks. All of the cells were CD45(-) and CD14(-), and expressed several endothelial markers (UEA-1, VWF, P1H12, CD105, E-selectin, VCAM-1 and VE-cadherin) and typical Weibel-Palade bodies. They had a high proliferative potential (up to a 2400-fold increase in cell number after 3 weeks of culture) and the capacity to modulate cell surface antigens upon stimulation with inflammatory cytokines. Purified ECs were also co-cultivated with CD34(+) cells, in parallel with a purified fibroblastic cell monolayer. CD34(+) cells (10 x 10(5)) gave rise to 17,951 +/- 2422 CFU-GM colonies when grown on endothelial cells, and to 12,928 +/- 4415 CFU-GM colonies on fibroblast monolayers. The ECs also supported erythroid blast-forming unit (BFU-E) colonies better. These results suggest that bone marrow CD133(+) progenitor cells can give rise to highly purified ECs, which have a high proliferative capacity, can be activated by inflammatory cytokines and are superior to fibroblasts in supporting haematopoiesis. Our data support the hypothesis that endothelial cell progenitors are present in adult bone marrow and may contribute to neo-angiogenesis.
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PMID:Differentiation and expansion of endothelial cells from human bone marrow CD133(+) cells. 1172 32

Here, we report that the number of CD11c(+)CD3(-) B220(-) cells increases in autoimmune-prone male (NZW x BXSB)F1 (W/BF1) mice with age. The CD11c(+)CD3(-)B220(-) cells from W/BF1 mice show a typical stellate shape and induce the proliferation of T cells. In the CD11c(+)CD3(-)B220(-) cells from W/BF1 mice, CD11b (Mac-1alpha), NK 1.1, and CD95 (Fas) are upregulated in comparison with normal mice, while the expression of CD8alpha, CD117 (c-kit), CD135 (Flk-2/Flt-3), and Sca-1 decreases. There is a significant increase in Flt-3L (FL) mRNA in the bone marrow of W/BF1 mice with age. Moreover, activated hemopoietic cells express high levels of FL. The injection of CD11c(+)CD3(-)B220(-) cells from old W/BF1 mice to young W/BF1 mice transiently induces autoimmune disease (thrombocytopenia). These results suggest that hyperproduction of FL from activated hemopoietic cells induces a dramatic increase in the number of dendritic cells in aged W/BF1 mice, followed by the acceleration of autoimmunity.
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PMID:Marked increase in number of dendritic cells in autoimmune-prone (NZW x BXSB)F1 mice with age. 1179 23


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