bluuebunny/crossref_metadata_2025_split huggingface dataset:
Tat–Human Immunodeficiency Virus-1 Induces Human Monocyte Chemotaxis by Activation of Vascular Endothelial Growth Factor Receptor-1
Authors: Mitola Stefania , Sozzani Silvano , Luini Walter , Primo Luca , Borsatti Alessandro , Weich Herbert , Bussolino Federico 
Published: October 2019

AbstractHuman immunodeficiency virus-1 (HIV-1) Tat protein can be released by infected cells and activates mesenchymal cells. Among these, monocytes respond to Tat by migrating into tissues and releasing inflammatory mediators. In the present study, we have examined the molecular mechanism of monocyte activation by Tat, showing that this viral protein signals inside the cells through the tyrosine kinase receptor for vascular endothelial growth factor encoded by fms-like tyrosine kinase gene (VEGFR-1/Flt-1). Subnanomolar concentrations of Tat induced monocyte chemotaxis, which was inhibited by cell preincubation with vascular-endothelial growth factor-A (VEGF-A). This desensitisation was specific for VEGF-A, because it not was observed with FMLP. In addition, the soluble form of VEGFR-1 specifically inhibited polarization and migration induced by Tat and VEGF-A, thus confirming the common use of this receptor. Binding studies performed at equilibrium by using radiolabeled Tat showed that monocytes expressed a unique class of binding site, with a kd of approximately 0.2 nmol/L. The binding of radiolabeled Tat to monocyte surface and the cross-linking to a protein of 150 kD was inhibited specifically by an excess of cold Tat or VEGF-A. Western blot analysis with an antibody anti–VEGFR-1/Flt-1 performed on monocyte phosphoproteins immunoprecipitated by an monoclonal antibody antiphosphotyrosine showed that Tat induced a rapid phosphorylation in tyrosine residue of the 150-kD VEGFR-1/Flt-1. Taken together, these results suggest that biologic activities of HIV-1 Tat in human monocytes may, at least in part, be elicited by activation of VEGFR-1/Flt-1.
flt3 Ligand in Cooperation With Transforming Growth Factor-β1 Potentiates In Vitro Development of Langerhans-Type Dendritic Cells and Allows Single-Cell Dendritic Cell Cluster Formation Under Serum-Free Conditions
Authors: Strobl Herbert , Bello-Fernandez Concha , Riedl Elisabeth , Pickl Winfried F. , Majdic Otto , Lyman Stewart D. , Knapp Walter 
Published: October 2019

AbstractUsing a recently described serum-free culture system of purified human CD34+ progenitor cells, we show here a critical cooperation of flt3 ligand (FL) with transforming growth factor-β1 (TGF-β1) in the induction of in vitro dendritic cell/Langerhans cell (DC/LC) development. The addition of FL to serum-free cultures of CD34+ cells supplemented with TGF-β1, granulocyte-macrophage colony-stimulating factor, tumor necrosis factor α, and stem cell factor strongly increases both percentages (mean, 36% ± 5% v 64% ± 4%; P = .001) and total numbers (4.4- ± 0.8-fold) of CD1a+ dendritic cells. These in vitro-generated CD1a+ cells molecularly closely resemble a particular type of DC known as an epidermal Langerhans cell. Generation of DC under serum-free conditions was found to strictly require supplementation of culture medium with TGF-β1. Upon omission of TGF-β1, percentages of CD1a+ DC decreased (to mean, 10% ± 8%; P = .001) and, in turn, percentages of granulomonocytic cells (CD1a− cells that are lysozyme [LZ+]; myeloperoxidase [MPO+]; CD14+) increased approximately threefold (P < .05). Furthermore, in the absence of TGF-β1, FL consistently promotes generation of LZ+, MPO+, and CD14+ cells, but not of CD1a+ cells. Serum-free single-cell cultures set up under identical TGF-β1– and FL-supplemented culture conditions showed that high percentages of CD34+ cells (mean, 18% ± 2%; n = 4) give rise to day-10 DC colony formation. The majority of cells in these DC-containing colonies expressed the Langerhans cell/Birbeck granule specific marker molecule Lag. Without TGF-β1 supplementation, Lag+ colony formation is minimal and formation of monocyte/macrophage-containing colonies predominates. Total cloning efficiency in the absence and presence of TGF-β1 is virtually identical (mean, 41% ± 6% v 41% ± 4%). Thus, FL has the potential to strongly stimulate DC/LC generation, but has a strict requirement for TGF-β1 to show this costimulatory effect.
Adenovirus-Mediated Transfer of Tissue-Type Plasminogen Activator Augments Thrombolysis in Tissue-Type Plasminogen Activator–Deficient and Plasminogen Activator Inhibitor-1–Overexpressing Mice
Authors: Carmeliet Peter , Stassen Jean-Marie , Van Vlaenderen Ilse , Meidell Robert S. , Collen Désiré , Gerard Robert D. 
Published: October 2019

AbstractImpaired fibrinolysis, resulting from increased plasminogen activator inhibitor-1 (PAI-1) or reduced tissue-type plasminogen activator (t-PA) plasma levels, may predispose the individual to subacute thrombosis in sepsis and inflammation. The objective of these studies was to show that adenovirus-mediated gene transfer could increase systemic plasma t-PA levels and thrombolytic capacity in animal model systems. Recombinant adenovirus vectors were constructed that express either human wild type or PAI-1–resistant t-PA from the cytomegalovirus (CMV) promoter. Both t-PA-deficient (t-PA−/−) and PAI-1–overexpressing transgenic mice were infected by intravenous injection of these viruses. Intravenous injection of recombinant adenovirus resulted in liver gene transfer, t-PA synthesis, and secretion into the plasma. Virus dose, human t-PA antigen, and activity concentrations in plasma and extent of lysis of a 125I-fibrin–labeled pulmonary embolism were all closely correlated. Plasma t-PA antigen and activity were increased approximately 1,000-fold above normal levels. Clot lysis was significantly increased in mice injected with a t-PA–expressing virus, but not in mice injected with saline or an irrelevant adenovirus. Comparable levels of enzyme activity and clot lysis were obtained with wild type and inhibitor-resistant t-PA viruses. Adenovirus-mediated t-PA gene transfer was found to augment clot lysis as early as 4 hours after infection, but expression levels subsided within 7 days. Adenovirus-mediated transfer of a t-PA gene can effectively increase plasma fibrinolytic activity and either restore (in t-PA–deficient mice) or augment (in PAI-1–overexpressing mice) the thrombolytic capacity in simple animal models of defective fibrinolysis.
A Factor V Genetic Component Differing From Factor V R506Q Contributes to the Activated Protein C Resistance Phenotype
Authors: Bernardi F. , Faioni E.M. , Castoldi E. , Lunghi B. , Castaman G. , Sacchi E. , Mannucci P.M. 
Published: October 2019

AbstractFactor V gene polymorphisms were investigated to detect components that may contribute to the activated protein C (APC) resistance phenotype in patients with venous thromboembolism. A specific factor V gene haplotype (HR2) was defined by six polymorphisms and its frequency was found to be similar in normal subjects coming from Italy (0.08), India (0.1), and Somalia (0.08), indicating that it was originated by ancestral mutational events. The relationship between the distribution of normalized APC ratios obtained with the functional assay and haplotype frequency was analyzed in patients heterozygous for factor V R506Q (factor V Leiden). The HR2 haplotype was significantly more frequent in patients with ratios below the 15th percentile than in those with higher ratios or in normal controls. Moreover, the study of 10 patients with APC resistance in the absence of the factor V R506Q mutation showed a 50-fold higher frequency of HR2 homozygotes. The HR2 haplotype was associated with significantly lower APC ratios both in patients with venous thromboembolism and in age- and sex-matched controls. However, the two groups showed similar HR2 haplotype frequencies. Plasma mixing experiments showed that an artificially created double heterozygote for the factor V R506Q mutation and the HR2 haplotype had an APC ratio lower than that expected for a simple R506Q heterozygote. Time-course experiments evaluating the decay of factor V in plasma showed the normal stability of the molecule encoded by the factor V gene marked by the HR2 haplotype, which ruled out the presence of a pseudo-homozygous APC resistance mechanism. Our results provide new insights into the presence of factor V genetic components other than the factor V R506Q that are able to contribute to the APC resistance phenotype in patients with venous thromboembolism.
Expression of the Neural Cell Adhesion Molecule CD56 Is Associated With Short Remission Duration and Survival in Acute Myeloid Leukemia With t(8; 21)(q22; q22)
Authors: Baer Maria R. , Stewart Carleton C. , Lawrence David , Arthur Diane C. , Byrd John C. , Davey Frederick R. , Schiffer Charles A. , Bloomfield Clara D. 
Published: October 2019

Abstract
Although acute myeloid leukemia (AML) with t(8; 21) (q22; q22) is associated with a high complete remission (CR) rate and prolonged disease-free survival, treatment outcome is not universally favorable. Identifying factors that predict for treatment outcome might allow therapy to be optimized based on risk. AML with t(8; 21) has a distinctive immunophenotype, characterized by expression of the myeloid and stem cell antigens CD13, CD15, CD34, and HLADr, and frequent expression of the B-cell antigen CD19 and the neural cell adhesion molecule CD56, a natural killer cell/stem cell antigen. Because CD56 expression has been associated with both extramedullary leukemia and multidrug resistance, we sought to correlate CD56 expression with treatment outcome in AML with t(8; 21). Pretreatment leukemia cells from 29 adult de novo AML patients with t(8; 21) treated on Cancer and Leukemia Group B (CALGB) protocols were immunophenotyped by multiparameter flow cytometry as part of a prospective immunophenotyping study of adult AML (CALGB 8361). CD56 was expressed in 16 cases (55%). There was no correlation between CD56 expression and age, sex, white blood cell count, granulocyte count, the presence of additional cytogenetic abnormalities, or the presence of extramedullary disease at diagnosis. The CR rate to standard-dose cytarabine and daunorubicin was similar for cases with and without CD56 expression (88% v 92%; P = 1.0). Post-CR therapy included at least one course of high-dose cytarabine in 24 of 26 patients who achieved CR; numbers of courses administered were similar in cases with and without CD56 expression. Although post-CR therapy did not differ, CR duration was significantly shorter in cases with CD56 expression compared with those without (median, 8.7 months v not reached; P = .01), as was survival (median, 16.5 months v not reached; P = .008). We conclude that CD56 expression in AML with t(8; 21) is associated with significantly shorter CR duration and survival. Our results suggest that CD56 expression may be useful in stratifying therapy for this subtype of AML.
Skewed X-Inactivation in Carriers of X-Linked Dyskeratosis Congenita
Authors: Vulliamy T.J. , Knight S.W. , Dokal I. , Mason P.J. 
Published: October 2019

Abstract
A gene causing Dyskeratosis Congenita (DC), a rare genetic disorder associated with bone marrow failure, has been mapped to chromosome Xq28, but autosomal inheritance of the disease has also been reported. We have investigated the pattern of X-inactivation in the peripheral blood of carriers of DC using the methylation-sensitive Hpa II site in the androgen receptor gene (HUMARA). In 5 different families in which the inheritance of DC appears to be X-linked, all 16 carriers showed skewed X-inactivation patterns. These cases indicate that, in the hematopoiesis of heterozygous females, cells expressing the normal DC allele have a growth advantage over cells that express the mutant allele. In 7 other families with sporadic cases of DC or with an uncertain pattern of inheritance, both skewed and normal patterns of X-inactivation were observed. In these families or where crucial family members are unavailable, the study of X-inactivation patterns will add to linkage analysis in providing information about carrier status.
Clonal Variability in β-Globin mRNA Content in an Interleukin-3–Dependent Bone Marrow Cell Line Transfected With the Erythropoietin Receptor Before and After Stimulation With Erythropoietin
Authors: Ishiguro Kimiko , Sartorelli Alan C. 
Published: October 2019

AbstractUnexpected clonal variability was observed in the content of β-globin mRNA in erythropoietin receptor (EpoR)-transfected Ba/F3 cells before and after exposure to erythropoietin (Epo). Of 11 clones selected by virtue of G418 resistance and positive EpoR expression, 5 clones showed high levels of βmajor-globin mRNA before Epo exposure, with subsequent Epo treatment causing little or no increase in globin mRNA. Five clones had undetectable levels of globin mRNA before Epo stimulation, and they did not accumulate globin mRNA when exposed to Epo, exhibiting resistance to the differentiation inducing action of Epo. Only one clone exhibited the expected phenotype, a low level of globin mRNA before exposure to Epo, and a significant Epo-dependent accumulation of globin mRNA. Phosphorylation of tyrosyl residues of the EpoR, Stat5, and JAK2 occurred upon Epo stimulation in clones representing each category. Furthermore, electrophoretic mobility shift assays using a Stat5 consensus sequence showed a difference in the nuclear binding component among these clones. These findings indicate that (1) the attainment of EpoR+ Ba/F3 clones with the anticipated sensitivity to both the growth and differentiation inducing actions of Epo is a rare event and (2) STAT5 transcription factors were differently activated by Epo in clones that differed in sensitivity to Epo.
Relative Importance of the Glycoprotein Ib-Binding Domain and the RGD Sequence of von Willebrand Factor for Its Interaction With Endothelial Cells
Authors: Perrault Christelle , Lankhof Hanneke , Pidard Dominique , Kerbiriou-Nabias Danièle , Sixma Jan J. , Meyer Dominique , Baruch Dominique 
Published: October 2019

AbstractEndothelial cell adhesion to von Willebrand Factor is mainly mediated through an interaction between the αvβ3 integrin and the RGD sequence of von Willebrand factor (vWF ). To define the potential involvement of glycoprotein Ibα (GPIbα) as an endothelial vWF receptor, we compared cell adhesion to three recombinant vWF, the wild-type (WT-rvWF ) and two mutants, RGGS-rvWF (D1746G), defective for binding to platelet αIIbβ3, and ΔA1-rvWF with a deletion between amino-acids 478 and 716, which does not bind to platelet GPIbα. Adhesion of human umbilical vein endothelial cells to purified vWF recombinants was measured by automatized cell counting using an image analyzer. Whereas cell adhesion to ΔA1-rvWF was unchanged compared with WT-rvWF, reaching a plateau of 40% total cells at a concentration of 2.5 μg/mL rvWF, adhesion to RGGS-rvWF was only 10% of total cells. Cell stimulation by tumor necrosis factor-α (TNFα), reported to upregulate the expression of the putative endothelial GPIbα, did not modify adhesion to these rvWF. Monoclonal antibodies to vWF or GPIbα, blocking vWF interaction with platelet GPIbα, were unable to inhibit endothelial cell adhesion to rvWF. In contrast, antibody 9 to vWF, blocking the αvβ3-dependent endothelial cell adhesion to plasma vWF, inhibited adhesion to WT-rvWF as efficiently as to ΔA1-rvWF (50% inhibition at a concentration of 11 and 15 μg/mL, respectively). In agreement with the fact that endothelial cell adhesion to vWF appeared independent of the GPIbα-binding domain, we were unable to detect endothelial surface expression of GPIbα by flow cytometry or in cell lysates by immunoprecipitation followed by immunoblotting. Moreover, expression of GPIbα mRNA was undetectable in endothelial cells, even after stimulation by TNFα. These studies indicate that GPIbα is not expressed in human cultured endothelial cells and is not involved in adhesion to vWF-containing surfaces. Thus, in static conditions, cultured endothelial cells adhere to vWF through an αvβ3-dependent, GPIbα-independent mechanism.
Dilazep, an Antiplatelet Agent, Inhibits Tissue Factor Expression in Endothelial Cells and Monocytes
Authors: Deguchi Hiroshi , Takeya Hiroyuki , Wada Hideo , Gabazza Esteban C. , Hayashi Nobuyuki , Urano Hajime , Suzuki Koji 
Published: October 2019

AbstractDilazep, an antiplatelet agent, is generally used as an antithrombotic drug in clinical practice. Dilazep is also known to exert cytoprotective and antioxidant effects on endothelial cells. However, its effect on the endothelial or monocyte procoagulant activity is unknown. In the current study, the effect of dilazep on the expression of tissue factor (TF ) in human umbilical vein endothelial cells (HUVECs) after the stimulation with tumor necrosis factor-α (TNF ), thrombin, or phorbol 12-myristate 13-acetate (PMA) was evaluated. We also evaluated the effect of dilazep on TNF (1,000 U/mL)-induced TF expression on monocytes. Dilazep inhibited TF activity induced on HUVECs by each stimulant, TNF (1000 U/mL), thrombin (25 nmol/L), or PMA (5 nmol/L) in a dose-dependent fashion (1 to 100 μg/mL). TF activity decreased to approximately 10% after treating with 100 μg/mL of dilazep. Dilazep also blocked the expression of TF antigen induced by each stimulant on the surface of HUVECs as determined by flow cytometric analysis. In addition, in HUVECs, it significantly decreased the expression of TF mRNA and the total TF antigen induced by thrombin or PMA, but not those induced by TNF, suggesting that dilazep blocks the TF expression induced by PMA or thrombin at a transcriptional level and that induced by TNF at a posttranscriptional level. Western blot analysis showed that dilazep reduces the accumulation of native TF but increases that in lower molecular weight TF derivatives. The adenosine receptor antagonist, 8-(p-sulfophenyl) theophylline, partially counteracted the anticoagulant activity of dilazep on HUVECs, thereby suggesting that the inhibitory effect of dilazep on TF expression in HUVECs depends, at least in part, on its adenosine potentiating activity. Dilazep also inhibited TNF-induced TF expression on monocytes in a dose-dependent fashion (0.1 to 100 μg/mL). In brief, the current study showed for the first time that dilazep, a commonly used antiplatelet drug, strongly inhibits the TF expression in HUVECs and monocytes. Dilazep may have a potent therapeutic value in patients with hypercoagulable state for its inhibitory property on the procoagulant activity of endothelial cells and monocytes.
New Xenograft Model of Multiple Myeloma and Efficacy of a Humanized Antibody Against Human Interleukin-6 Receptor
Authors: Tsunenari Toshiaki , Koishihara Yasuo , Nakamura Akito , Moriya Miki , Ohkawa Hiroyuki , Goto Hideo , Shimazaki Chihiro , Nakagawa Masao , Ohsugi Yoshiyuki , Kishimoto Tadamitsu , Akamatsu Ken-ichi 
Published: October 2019

Abstract
A new xenograft model of multiple myeloma (MM), where growth is strongly regulated by interleukin-6 (IL-6), was established in severe combined immunodeficiency (SCID) mice. In this model, endogenous IL-6 from SCID mice was ineffective at eliciting growth of the established human MM cell line KPMM2; these cells achieved autonomous growth through their autocrine secretion of IL-6. The etiopathology in this disease model is consistent with that of human MM. When greater than 3 × 106 KPMM2 cells were injected intravenously (IV), tumors developed in all mice and were predominantly localized in their bone marrow. Tumors were also apparent in the lymph nodes, but absent from other organs. Immunostaining of cell surface antigen (CD38) showed that more than 40% of bone marrow cells in femur were of myeloma origin in the advanced stage of tumor progression (day 37). Histologic analysis of these mice show that bone marrow was largely occupied by plasmablastic cells and bones had developed osteolytic lesions at multiple sites. Concurrently, there was a decrease in bone density throughout the body and a significant increase in ionized plasma calcium. M-protein was detected in the serum within 10 days after transplantation, which correlated with the tumor progression. Between 30 and 40 days after the transplantation, mice presented with a rapid and severe loss of body weight, hind leg paralysis, and fatigue. Subsequently, the mice died within a week. A single IV injection of 0.2 mg humanized anti–IL-6 receptor antibody (hPM1) into mice on the day after tumor transplantation substantially suppressed the elevation of serum M-protein and development of the tumor-associated abnormalities and significantly increased in the life span of tumor-bearing mice. Our data show the usefulness of this model to analyze the pathologic role of IL-6 in MM and the efficacy of targeting the IL-6 receptor in IL-6–dependent KPMM2 cells.
Immunophenotyping Investigation of Minimal Residual Disease Is a Useful Approach for Predicting Relapse in Acute Myeloid Leukemia Patients
Authors: San Miguel J.F. , Martı́nez A. , Macedo A. , Vidriales M.B. , López-Berges C. , González M. , Caballero D. , Garcı́a-Marcos M.A. , Ramos F. , Fernández-Calvo J. , Calmuntia M.J. , Diaz-Mediavilla J. , Orfao A. 
Published: October 2019

Abstract
A high complete remission rate is currently achieved in patients with acute myeloid leukemia (AML). However, many patients eventually relapse due to the persistence of low numbers of residual leukemic cells that are undetectable by conventional cytomorphologic criteria (minimal residual disease [MRD]). Using immunophenotypic multiparametric flow cytometry, we have investigated in sequential studies (diagnosis and follow-up) the impact of MRD detection on the outcome of 53 AML patients that had achieved morphologic remission with standard AML protocols and displayed at diagnosis an aberrant phenotype. Patients were studied at diagnosis with a panel of 35 monoclonal antibodies in triple staining combinations for detection of aberrant or uncommon phenotypic features. According to these features, a patient's probe was custom-built at diagnosis for the identification of possible residual leukemic cells during follow-up. The level of MRD at the end of induction and intensification therapy correlated with the number of relapses and relapse-free survival (RFS). Thus, patients with more than 5 × 10−3 residual cells (5 residual cells among 1,000 normal bone marrow [BM] cells) identified as leukemic by immunophenotyping in the first remission BM showed a significant higher rate of relapse (67% v 20% for patients with less than 5 × 10−3 residual cells; P = .002) and a lower median RFS (17 months v not reached; P = .01). At the end of intensification, with a cut-off value of 2 × 10−3 leukemic cells, AML patients also separated into two distinct groups with relapse rates of 69% versus 32% (P = .02), respectively, and median RFS of 16 months versus not reached (P = .04). In addition, overall survival was also significantly related to the level of residual cells in the marrow obtained at the end of induction and particularly after intensification therapy (P = .008). Furthermore, we have explored whether residual disease was related with the functional expression of multidrug resistance (MDR-1) at diagnosis as assessed by the rhodamine-123 assay. Patients with ≥5 × 10−3 residual leukemic cells at the end of induction therapy had a significantly higher rhodamine-123 efflux (mean, 56% ± 24%) than those with less than 5 × 10−3 residual cells (mean, 32% ± 31%; P = .04). Finally, multivariate analysis showed that the number of residual cells at the end of induction or intensification therapy was the most important prognostic factor for prediction of RFS. Overall, our results show that immunophenotypical investigation of MRD strongly predicts outcome in patients with AML and that the number of residual leukemic cells correlates with multidrug resistance.