bluuebunny/crossref_metadata_2025_split huggingface dataset:
Expression of Prostacyclin Receptor in Human Megakaryocytes
Authors: Sasaki Yutaka , Takahashi Takayuki , Tanaka Issei , Nakamura Kishiko , Okuno Yoshiaki , Nakagawa Osamu , Narumiya Shuh , Nakao Kazuwa 
Published: October 2019

AbstractProstacyclin (prostaglandin I2, PGI2) is a potent vasodilator and inhibitor of platelet aggregation. Although it is well known that the specific receptor for prostacyclin (PGI2-R) is abundantly expressed on platelets, PGI2-R expression in megakaryocytes is poorly understood. In this study, we examined its expression in leukemic or normal megakaryocytes. PGI2-R mRNA was expressed in human leukemic cell lines of megakaryocytic nature as evaluated by Northern blot analysis. Phorbol 12-myristate 13-acetate (PMA), interleukin-1 (IL-1), IL-3, IL-6, granulocyte-macrophage colony-stimulating factor (GM-CSF ), thrombopoietin (TPO), and tumor necrosis factor-α (TNF-α) enhanced PGI2-R mRNA expression. The enhancement of PGI2-R expression by PMA and TPO was associated with the upregulation of platelet factor 4 or glycoprotein IIb mRNA expression. Iloprost, an agonist of prostacyclin, induced significant cyclic (c)AMP synthesis in these leukemic cells indicating that interaction of PGI2-R and its ligand can induce postreceptor signal transduction. Furthermore, iloprost-induced cAMP synthesis was enhanced by the pretreatment with PMA or the cytokines that promoted PGI2-R expression. PMA and TPO also increased the specific binding of [3H]iloprost to these cells. Pooled normal megakaryocytic colonies from TPO-containing semisolid culture of purified human CD34+ cells expressed PGI2-R, which were increased as the megakaryocytes matured with the peak expression before proplatelet formation, as evaluated by semiquantitative reverse transcription-polymerase chain reaction (RT-PCR). These results indicate that PGI2-R is expressed in human megakaryocytes and is upregulated by cytokines involved in thrombopoiesis or inflammation. Also, it was indicated that megakaryocytic maturation accompanies enhancement of PGI2-R expression.
HLA Class II Restricted T-Cell Reactivity to a Developmentally Regulated Antigen Shared by Leukemic Cells and CD34+ Early Progenitor Cells
Authors: Mutis Tuna , Schrama Ellen , A.P. van Luxemburg-Heijs Simone , Falkenburg J.H.F , Melief Cornelis J.M. , Goulmy Els 
Published: October 2019

AbstractAfter allogeneic bone marrow transplantation (BMT), the beneficial graft-versus-leukemia (GVL) effect but also the life-threatening graft-versus-host disease (GVHD) are mediated by T cells of the grafted marrow. The identification of leukemia cell–reactive T cells and their ligands are, therefore, crucial for the development of new anti leukemia strategies. Here we describe a leukemia-reactive allo-HLA class II restricted CD4+ T-cell clone, 6.2, isolated from a healthy individual after stimulation with allogeneic leukemic cells. Clone 6.2 recognizes leukemic cells from several AML patients without showing reactivity to unfractioned peripheral blood mononuclear cells, monocytes, B cells, T-cell blasts, and proximal tubulus epithelial cells. Interestingly, clone 6.2 also recognizes BM cells derived from healthy individuals and inhibits the colony formation of myeloid and erythroid cell lineages. In the BM, clone 6.2 recognizes only CD34+ early precursor cells but not CD34−, more differentiated cells. Thus, the target antigen of clone 6.2 is developmentally regulated and expressed only by leukemic cells and CD34+ early progenitor cells in the hematopoietic system. We suggest that targeting the T-cell immune response to leukemia-associated, developmentally regulated antigens of the hematopoietic system can provide a basis for the separation of GVL from GVHD, and may lead to new therapeutic approaches for residual and relapsed leukemia.
CD44 Is Involved in Tumor Angiogenesis; an Activation Antigen on Human Endothelial Cells
Authors: Griffioen Arjan W. , Coenen Marieke J.H. , Damen Cora A. , Hellwig Sandra M.M. , H.J. van Weering David , Vooys Wim , Blijham Geert H. , Groenewegen Gerard 
Published: October 2019

AbstractCD44 is described to be an activation molecule in a number of different cell types. We investigated the role of CD44 on human endothelial cells (EC) and in tumor angiogenesis. Using flow cytometry we showed that EC from the vasculature of human solid tumors display an enhanced expression of CD44 as compared to EC from normal tissue. This finding was confirmed by immunohistochemical studies on frozen tissue sections. Because tumors are dependent on angiogenesis, the role of angiogenic stimuli in the enhanced CD44 expression was investigated. We found that basic fibroblast growth factor (bFGF ) and vascular endothelial growth factor were able to efficiently upregulate CD44 expression on cultured human EC. The upregulation reached maximal levels after treatment for 3 days with 10 ng/mL bFGF. The physiological impact of this upregulation was shown by the enhanced binding of EC to hyaluronate after pretreatment with bFGF. In a next set of studies that were designed to unravel the regulation of CD44 expression on EC we concluded that CD44 is an activation antigen on human EC since (1) human umbilical vein derived endothelial cells, which in vivo do not express CD44, begin to express CD44 when plated and cultured, (2) CD44 expression is enhanced after subculture of confluent cultures, (3) CD44 is predominantly expressed on the BrdU incorporating subset of cultured EC. The specific expression of CD44 on activated and tumor EC prompted us to study the usefulness of CD44 as an endothelial target for therapy with immunotoxins. In vitro experiments showed that EC are efficiently killed after targeting immunotoxin to CD44.
Bcl-2 and Bcl-XL Can Differentially Block Chemotherapy-Induced Cell Death
Authors: Simonian Philip L. , Grillot Didier A.M. , Nuñez Gabriel 
Published: October 2019

AbstractBcl-2 and its homologue Bcl-XL are expressed in a variety of tumors and their expression modulates the sensitivity of tumor cells to a wide spectrum of chemotherapeutic agents and γ-irradiation. In the present report, we generated clones of FL5.12 lymphoid cells with similar levels of Bcl-2 and Bcl-XL using the Flag epitope to determine if these survival proteins could provide equivalent protection when challenged with chemotherapy or γ-irradiation. Using four M-phase specific chemotherapeutic agents, Bcl-XL and Bcl-2 provided similar protection against vincristine and vinblastine whereas Bcl-XL afforded as much as 50% greater cell viability than Bcl-2 against etoposide and teniposide-induced cell death. In addition, Bcl-XL provided significantly greater cell viability than Bcl-2 against methotrexate, fluorouracil, and hydroxyurea, three S-phase specific agents. In apoptosis induced by γ-irradiation and cisplatin, two antitumor treatments that are cell-cycle phase-nonspecific agents, both Bcl-XL and Bcl-2 conferred similar protection against γ-irradiation, but Bcl-XL provided better protection than Bcl-2 against cisplatin. These results indicate that Bcl-XL and Bcl-2 confer a differential ability to protect against chemotherapy-induced cell death, which appears to be dependent on the molecular mechanism targeted by the drug rather than its cell-cycle phase specificity.
Expression and Intracellular Localization of the Human N-acetylmuramyl-L-alanine Amidase, a Bacterial Cell Wall–Degrading Enzyme
Authors: Hoijer M.A. , Melief M.J. , Calafat J. , Roos D. , van den Beemd R.W.M. , van Dongen J.J.M. , Hazenberg M.P. 
Published: October 2019

AbstractN-acetylmuramyl-L-alanine amidase (NAMLAA) specifically degrades peptidoglycan, which is a major component of bacterial cell walls with strong inflammatory properties. For instance, peptidoglycan is capable of stimulating peripheral blood cells to release pro-inflammatory cytokines and is capable of inducing chronic arthritis in an animal model. In a previous study we found that degradation of peptidoglycan by purified NAMLAA reduced its inflammatory effects. To determine where NAMLAA is located in tissues, monoclonal antibodies against purified NAMLAA were produced for use in immunohistochemistry, immunoelectron microscopy, flow cytometric analysis, and Western blotting. The immunohistochemical studies showed NAMLAA-positive cells in human spleen, liver, arthritic synovial tissues, and lymph nodes. In flow cytometric studies of blood and bone marrow, neutrophilic and eosinophilic granulocytes proved to be positive. Monocytes were negative, although they do contain lysozyme, the other important peptidoglycan-degrading enzyme. However, mature macrophages obtained by bronchoalveolar lavage and subsequent selection based on auto-fluorescence did possess NAMLAA. In immunocytochemical staining of blood smears, thrombocytes were also positive for NAMLAA. Western blot analysis and immunoelectron microscopy of neutrophils and eosinophils showed that NAMLAA is located in azurophilic granules of neutrophils and in secretory vesicles and crystalloid-containing granules of eosinophils. Flow cytometric analysis of blood and bone marrow from different French-American-British–classified acute myeloid leukemia (AML) patients showed that AML-M2 myeloblasts were the first in the granulocyte maturation lineage that were positive for NAMLAA. The more immature AML, such as AML-M0 and AML-M1, did not express NAMLAA. CD15- and CD13-negative megakaryoblasts, corresponding to AML-M7, were also positive for NAMLAA. The expression pattern of NAMLAA in the myeloid lineage suggests that the monoclonal antibody AAA4, recognizing NAMLAA, is useful for discrimination between AML in the monocyte lineage and in the granulocyte lineage.
Ubiquitin Aldehyde Increases Adenosine Triphosphate–Dependent Proteolysis of Hemoglobin α-Subunits in β-Thalassemic Hemolysates
Authors: Shaeffer Joseph R. , Cohen Robert E. 
Published: October 2019

AbstractTwo major causes of the anemia in β-thalassemia are a deficiency in hemoglobin (Hb) β-subunit (and consequently HbA) synthesis and, due to the resulting excess of Hb α-subunits, erythroid cell hemolysis. The hemolytic component might be ameliorated by increasing the intracellular proteolysis of the excess α-subunits. Isolated 3H-labeled α-chains are known to be degraded primarily by the adenosine triphosphate (ATP)- and ubiquitin (Ub)-dependent proteolysis pathway in unfractionated β-thalassemic hemolysates. Our objective was to increase this degradation by targeted intervention. Ub aldehyde (Ubal), a synthetic inhibitor of isopeptidases (proteases that hydrolyze the bond between the Ub polypeptide and its protein adduct), was added to reaction mixtures containing a hemolysate from the blood cells of one of four β-thalassemic donors and 3H-α-chains or 3H-α-globin as a substrate. Optimum enhancement of ATP-dependent degradation occurred at 0.4 to 1.5 μmol/L Ubal and ranged from 29% to 115% for 3H-α-chains and 47% to 96% for 3H-α-globin among the four hemolysates. We suggest that Ubal stimulates 3H-α-subunit proteolysis by inhibition of an isopeptidase(s) that deubiquitinates, or “edits,” Ub-3H-α-subunit conjugates, intermediates in the degradative pathway. In control studies, similarly low Ubal concentrations did not enhance the degradation of 3H-α2β2 (HbA) tetramers or inhibit the activities of methemoglobin reductase and four selected glycolysis pathway enzymes. These and other results may be the basis for a therapeutic approach to β-thalassemia.
Hepatitis C and G Virus Infection and Liver Dysfunction After Allogeneic Bone Marrow Transplantation: Results From a Prospective Study
Authors: Rodriguez-Iñigo Elena , Tomás José-Francisco , Gómez-Garcı́a de Soria Valle , Bartolomé Javier , Pinilla Inmaculada , Amaro Marı́a-José , Carreño Vicente , Fernández-Rañada José-Marı́a 
Published: October 2019

Abstract
Acute and chronic liver dysfunction is common after allogeneic bone marrow transplantation (BMT). Although toxicity, graft versus-host disease (GVHD), and viral infections are the major causes, etiologic diagnosis is difficult and often remains unknown. We conducted a prospective study to establish the role of the infection with both the hepatitis C virus (HCV) and the recently discovered hepatitis G virus (HGV) in liver dysfunction after BMT. From January 1994 to December 1995, 59 patients who had undergone an allogeneic BMT at our institution were enrolled in the study. HGV-RNA was identified in serum by nested polymerase chain reaction (PCR), and HCV was studied by the presence of second generation enzyme-linked immunosorbent assay (ELISA)-antibodies and HCV-RNA by nested PCR. HGV-RNA was detected in 25 patients (42%) (before BMT in 18 and after BMT in 7). HCV-RNA was present in 12 patients (20%) (before BMT in 11 and after BMT in one). The presence of HCV-RNA and HGV-RNA was clearly associated with a previous history of blood transfusions. No significant association was found between viral infection and acute liver toxicity. Some degree of liver dysfunction was present 6 months after BMT in 25 of 40 evaluable patients (62%). Long-term liver dysfunction was more common among patients infected with HCV alone (3 of 4) or with both HCV and HGV (3 of 3) than in those infected with either HGV alone (eight of 13) or with no virus infection (10 of 20). We found a high prevalence of HGV infection in our BMT population. However, no role for HGV in liver disease could be established in this study, and the relationship between HGV infection and liver dysfunction requires further clarification.
Fusarium, a Significant Emerging Pathogen in Patients With Hematologic Malignancy: Ten Years' Experience at a Cancer Center and Implications for Management
Authors: Boutati Eleni I. , Anaissie Elias J. 
Published: October 2019

AbstractDespite increasing reports of life-threatening Fusarium infections, little is known about its pathogenesis and management. To evaluate the epidemiology, clinicopathologic features, and outcome of invasive fusariosis in patients with hematologic cancer, we conducted a retrospective study of invasive fusarial infections in patients with hematologic malignancy treated at a referral cancer center over a 10-year period (1986 to 1995), as well as a literature review. Forty patients with disseminated and three patients with invasive lung infection were included in the analysis. All patients were immunocompromised. The infection occurred in three patients postengraftment following bone marrow transplantation. All patients were diagnosed antemortem. Thirteen patients responded to therapy, but the infection relapsed in two of them. Response was associated with granulocyte transfusions, amphotericin B lipid formulations (four patients each), and an investigational triazole (two patients). Resolution of infection was only seen in patients who ultimately recovered from myelosuppression. Portal of entry was the skin (33%), the sinopulmonary tree (30%), and unknown (37%). Fusarium causes serious morbidity and mortality, and may mimic aspergillosis. The infection seems to respond to newer therapeutic approaches, but only in patients with ultimate recovery from myelosuppression, and it may relapse if neutropenia recurs.
Improved Sensitivity of BCR-ABL Detection: A Triple-Probe Three-Color Fluorescence In Situ Hybridization System
Authors: Sinclair P.B. , Green A.R. , Grace C. , Nacheva E.P. 
Published: October 2019

Abstract
Chronic myeloid leukemia is a clonal stem cell disorder associated with the Philadelphia (Ph) translocation [t(9; 22) (q34; q11)]. As a result of the Ph translocation, parts of the ABL and BCR genes become fused. Cytogenetic quantification of Ph+ metaphases can be used to monitor patient response to treatment but is of limited sensitivity and applies only to cycling cells. Fluorescence in situ hybridization (FISH) with probes from the BCR and ABL regions can also identify the Ph translocation in interphase cells. Established systems for the detection of fusion genes by FISH rely on colocalization of two different probes but are associated with a high rate of false-positive results. We have introduced a third probe labeled with a different fluorochrome to create a triple-probe/three-color system that permits identification of both the Ph chromosome and the derivative 9 chromosome in Ph+ cells. This system was used to determine the frequency of interphase cells carrying the BCR-ABL fusion gene in bone marrow and peripheral blood granulocytes from patients showing variable cytogenetic responses to interferon. Our data show that the triple-probe/three-color approach allows highly sensitive detection of residual disease. Moreover, this method is readily applicable to the analysis of other chromosome translocations.
Anandamide, a Natural Ligand for the Peripheral Cannabinoid Receptor Is a Novel Synergistic Growth Factor for Hematopoietic Cells
Authors: Valk Peter , Verbakel Sandra , Vankan Yolanda , Hol Samantha , Mancham Shanta , Ploemacher Rob , Mayen Angelique , Löwenberg Bob , Delwel Ruud 
Published: October 2019

AbstractWe recently demonstrated that the gene encoding the peripheral cannabinoid receptor (Cb2) may be a proto-oncogene involved in murine myeloid leukemias. We show here that Cb2 may have a role in hematopoietic development. RNAse protection analysis showed that Cb2 is normally expressed in spleen and thymus. Cb2 mRNA is also expressed in 45 of 51 cell lines of distinct hematopoietic lineages, ie, myeloid, macrophage, mast, B-lymphoid, T-lymphoid, and erythroid cells. The effect of the fatty acid anandamide, an endogenous ligand for cannabinoid receptors, on primary murine marrow cells and hematopoietic growth factor (HGF )-dependent cell lines was then investigated. In vitro colony cultures of normal mouse bone marrow cells showed anandamide to potentiate interleukin-3 (IL-3)–induced colony growth markedly. Whereas HGFs alone stimulate proliferation of the various cell lines in serum-free culture only weakly, anandamide enhances the proliferative response of the cell lines to HGFs profoundly. This was apparent for responses induced by IL-3, granulocyte-macrophage colony-stimulating factor, granulocyte colony-stimulating factor, and erythropoietin. Anandamide was already effective at concentrations as low as 0.1 to 0.3 μmol/L and plateau effects were reached at 0.3 to 3 μmol/L. The addition of anandamide as single growth factor had no effect. The costimulatory effect of anandamide was not evident when cells were cultured with fetal calf serum (FCS), suggesting that FCS contains anandamide or another ligand capable of activating the peripheral cannabinoid receptor. Other cannabinoid ligands did not enhance the proliferative responsiveness of hematopoietic cells to HGFs. Transfection experiments of Cb2 in myeloid 32D cells showed that anandamide specifically activates proliferation through activation of the peripheral cannabinoid receptor. Anandamide appears to be a novel and synergistic growth stimulator for hematopoietic cells.
Significance of RGD Loop and C-Terminal Domain of Echistatin for Recognition of αIIbβ3 and αvβ3 Integrins and Expression of Ligand-Induced Binding Site
Authors: Marcinkiewicz Cezary , Vijay-Kumar Senadhi , McLane Mary Ann , Niewiarowski Stefan 
Published: October 2019

AbstractEchistatin is a viper venom disintegrin containing RGD loop maintained by disulfide bridges. It binds with a high affinity to αvβ3 and αIIbβ3 and it induces extensive conformational changes in these integrins resulting in expression of ligand-induced binding site (LIBS) epitopes. We investigated the activities of echistatin and its three analogues (R24A, D27W, echistatin 1-41). R24A echistatin did not react with αIIbβ3 and αvβ3 integrins and did not cause LIBS effect. D27W echistatin showed increased binding to αIIbβ3 and decreased binding to αvβ3. This substitution impaired the ability of echistatin to induce LIBS in αvβ3 integrin. Deletion of nine C-terminal amino acids of echistatin decreased its ability to bind αIIbβ3 and inhibit platelet aggregation. Truncated echistatin failed to induce LIBS epitopes on cells transfected with αIIbβ3 and αvβ3 genes. The ability of echistatin 1-41 to compete with binding of vitronectin to immobilized αvβ3 and monoclonal antibody 7E3 to platelets and to VNRC3 cells was decreased, although this analogue, after immobilization, retained its ability to bind purified αvβ3. We propose a hypothesis in which echistatin's RGD loop determines selective recognition of αIIbβ3 and αvβ3 integrin, whereas the C-terminal domain supports its binding to resting integrin and significantly contributes to the expression of LIBS epitope and to conformational changes of the receptor, leading to a further increase of the binding affinity of echistatin and of the inhibitory effect.
Presentation of Exogenous Protein Antigens on Major Histocompatability Complex Class I Molecules by Dendritic Cells: Pathway of Presentation and Regulation by Cytokines
Authors: Brossart Peter , Bevan Michael J. 
Published: October 2019

AbstractSeveral recent studies have shown that dendritic cells (DC) pulsed with soluble proteins can present peptide epitopes derived from these exogenous antigens on major histocompatability complex (MHC) class I molecules and induce an antigen-specific cytotoxic T lymphocyte (CTL) response. We provide evidence here that DC use macropinocytosis to capture soluble antigens that are then presented on MHC class I molecules. The presentation of an epitope derived from soluble ovalbumin was transporter associated with antigen presentation (TAP)-dependent, brefeldin A-sensitive, blocked by inhibitors of proteasomes, and resistant to chloroquine. These data suggest that exogenous antigens access the cytosol of DC and are proccessed for presentation via the same pathway described for conventional MHC class I-restricted cytosolic antigens. Proinflammatory mediators such as tumor necrosis factor-α (TNF-α) and lipopolysaccharide (LPS) reduced the efficiency of ovalbumin presentation via this pathway. This reduced presentation was not due to impaired expression of class I molecules because these substances upregulated the cell surface expression of Kb-molecules comparable to levels induced by interferon-γ (IFN-γ) treatment. The addition of IFN-γ increased ovalbumin presentation even in the presence of TNF-α or LPS. These results show that DC might be involved in the cross-priming phenomenon. This could offer the immune system an additional pathway for effective priming of cytotoxic T cells and provide the possibility to activate both CD4 and CD8 T-cell responses.
Influence of pH on Phospholipid Redistribution in Human Erythrocyte Membrane
Authors: Libera Jeanette , Pomorski Thomas , Müller Peter , Herrmann Andreas 
Published: October 2019

AbstractThe influence of the suspension pH (pHo ) on the transmembrane mobility of spin-labeled phospholipid analogues in the human red blood cell was investigated. The passive transverse diffusion of spin-labeled phospholipid analogues was independent of pHo in the investigated range (5.8 to 8.5). However, upon acidification to pHo 5.8, a significant decrease of the rapid adenosine triphosphate (ATP)-dependent inward movement of aminophospholipids was found at physiologic ionic concentration, whereas a change of pH from 7.4 to 8.5 did not affect this transport. Evidence is given that the intracellular pH affects the active transport of aminophospholipids but not the extracellular pH. Suppression of the ATP-dependent outside-inside redistribution of aminophospholipid analogues by low pH was reversible because original transport activity was re-established upon reneutralization. pH dependence of the active phospholipid transport was not caused by the spin-labeled reporter group or by depletion of intracellular ATP. Because the same influence of pH on aminophospholipid movement could be observed for resealed ghosts, constituents of the red blood cell cytoplasm do not mediate the influence of pH on the ATP-dependent inward movement of aminophospholipids.