bluuebunny/crossref_metadata_2025_split huggingface dataset:
Factor Xa Inhibitors Can Be Differentiated in Xa, IIa and Microparticle Generation and Other Whole Blood Based Assays.
Authors: Iqbal Omer , Adiguzel Cafer , Hoppensteadt Debra , Cunannan Josephine , Fareed Jawed 
Published: October 2019

Abstract
Currently used oral anticoagulants such as Vitamin K antagonists have drawbacks, which reportedly limit their safety and efficacy. Oral Factor Xa and IIa inhibitors are claimed to overcome these limitations. Factor Xa inhibitors provide more complete suppression of thrombin generation than Factor IIa inhibitors. Four Factor Xa anticoagulant agents, both direct and indirect, namely A,B,C and D with Ki values 6–200 nM, were studied in various assays at equigravimetric final concentration of 10 ug/ml to determine their relative potencies. Apparent differences in their biochemical profiles were noted in thrombin generation, Factor Xa generation and microparticle generation inhibition assays. Furthermore, the anticoagulant potential of these Xa inhibitors was studied in celite activated clotting time (ACT) and modified celite ACT system using different concentrations of tissue factor. Microparticle generation was performed using agent- supplemented whole blood that was incubated for three minutes with varying concentrations of tissue factor. Following three minutes the reaction was stopped using EDTA stop solution. The functional assay for the determination of microparticle procoagulant activity in the plasma was performed using Zymuphen MP-Activity assay kit from Hyphen BioMed (Neuville-sur-Oise, France). While three of the Xa inhibitors studied showed microparticle generation inhibition levels of 31.37 nM, one agent provided a level of 17.87 nM compared to a saline control value of 39.28nM. Supplementation studies were also carried out in whole blood PT, APTT and Heptest assays in the concentration range of 0 to 10 ug/ml. The whole blood prothrombin time assay showed a maximum of 208.8, 61.3, 77.8 and 15.9 seconds at a final concentration of 10 ug/ml for the respective anticoagulant agents when compared to a normal value of 12.3 seconds. Similarly the whole blood APTT assay showed a maximum of 267.9, 161.8, >300 and 71.9 seconds respectively when compared to a control value of 46.8 seconds. The whole blood Heptest assay showed a varying maximum anticoagulant effect from >300, 42.7, >300 and >300 seconds respectively when compared to a control value of 13.8 seconds. In each of these assays Factor Xa inhibitors showed concentration-dependent effects and had varying potencies. In TF-mediated platelet activation assays the different Xa agents produced varying effects which were not proportionate to their Ki values. Differentiation of Factor Xa inhibitors have a clinical impact in dosage selection, dosage adjustment and their monitoring when given in large dosages. Synthetic factor Xa agents exhibit Ki values of 20–200 nM, while pentasaccharide -AT complex has a Ki value of 60 nM. However, these results do not translate into proportionate anticoagulant effects to their Ki values. Large-scale clinical studies are necessary to validate these preliminary results.
Fibrinolytic Agents for Restoration of Central Venous Catheter Patency: A Systematic Review.
Authors: Wang Myra , Kagoma Yoan , Lim Wendy , Clase Catherine M. , Crowther Mark A. 
Published: October 2019

Abstract
Introduction. Thrombolytic agents are frequently used as an aid to restore catheter patency despite limited evidence supporting their use. We therefore conducted a systematic review to evaluate the efficacy of tPA (alteplase) and reteplase in restoring catheter patency.
Methods. We searched MEDLINE (1999 to May Week 3 2007) and the Cochrane Controlled Clinical Trials Register (Second Quarter 2007) and performed a manual search for further studies. Studies published before 1999 were excluded since they have been previously reviewed; furthermore, most such studies used urokinase, which is no longer used to restore catheter patency in North America. Studies were included if they described the efficacy of alteplase or reteplase in restoring patency of central venous catheters (either for hemodialysis or infusional treatment) and where more than 5 thrombotic episodes were reported. This latter exclusion criteria was used to reduce the likelihood of bias likely to be found in very small case series. Two independent researchers abstracted total thrombolytic dose administered, dwell times, catheter patency rates and adverse event (including bleeding rates). For purposes of comparison, dwell times were stratified as ≤ 30 minutes and 30 to 120 minutes.
Results. 25 articles were identified in the initial search, of which 17 met one or more exclusion criteria. Of the remaining 8 studies, 7 evaluated central venous catheters used for intravenous infusions and 1 study evaluated occluded hemodialysis catheters. Except for 1 randomized trial comparing thrombolytic agents to placebo in non-hemodialysis patients, all studies described uncontrolled cohorts or case series. The mean study size was 214 patients (range 6–995). At doses of 0.5–2.5 mg of alteplase, the range of catheter patency rates at dwell times of ≤ 30 minutes and 30 to 120 minutes were 52–54% (1301 total uses) and 69–91% (1466 total uses) respectively. In comparison when used with a ≤ 30 minute dwell time, reteplase was reported to restore catheter patency in 67–73% cases (154 total uses). In all reports bleeding complications attributed to thrombolytic therapy were uncommon.
Conclusion. Our review suggests that the installation of alteplase or reteplase will restore catheter patency in more than 50% of cases when used with a dwell time of at least 30 minutes. Longer dwell times appear to increase patency rates. Reteplase may be more effective than alteplase, although this observation should be validated in an adequately powered clinical trial. Overall, although modern thrombolytic agents appear to provide catheter patency in the majority of patients, the evidence supporting their use is of low quality and is not based on the results of randomized trials.
A Novel HIFalpha Mutation Associated with Familial Erythrocytosis Supports This Isoform Being the Major Regulator of Erythropoietin in Humans.
Authors: Percy Melanie J. , Furlow Paul W. , Lucas Guy S. , Li Xiping , Lappin Terry R. , McMullin Mary F. , Lee Frank S. 
Published: October 2019

Abstract
Red cell homeostasis is crucial to maintain a sustained tissue oxygen supply. Oxygen is sensed by the kidneys and hypoxia induces renal erythropoietin (Epo) to stimulate red cell production. At the molecular level this process is controlled by the hypoxia inducible factor (HIF) complex, comprised of a labile a-subunit and a constitutively expressed b subunit. Key prolines present in the oxygen-dependent degradation (ODD) domain of the a subunit are hydroxylated by prolyl hydroxylase domain proteins (PHD1-3). The von Hippel Lindau (VHL) protein then binds and targets HIFa to the proteasome. There are 3 isoforms of the a subunit, each of which shows differential tissue distribution. The HIF-1, HIF-2 and HIF-3a subunit, in association with the b subunit, exhibit diverse affinities for the hypoxia response elements (HREs) located in the promoters and enhancers of HIF target genes. It is unclear whether Epo synthesis is under the control of HIF-1 or HIF-2 in humans although recent studies in mice support HIF-2 as the critical regulator. Dysregulation of Epo production can give rise to the red cell disorder of erythrocytosis. Defects in the oxygen sensing pathway are commonly associated with erythrocytosis and mutations in both the VHL and PHD2 genes have been described. Previously, screening the ODD domain of HIF-1a detected a polymorphism, Pro582Ser, that did not impair the function of HIF-1a. Subsequently, when sequencing HIF-2a, a novel heterozygous c.G1609T mutation was uncovered in 3 generations of one family with erythrocytosis. All affected individuals exhibited greatly elevated serum Epo levels. The c.G1609T mutation was absent in other unaffected family members as well as a cohort of 200 normal control samples. The mutation predicts the replacement of Gly by Trp at amino acid 537, which is close to the main site of proline hydroxylation at 531. Functional assays confirmed the Gly537Trp variant was less hydroxylated and exhibited reduced affinity for PHD2. Furthermore, the increased stability in normoxia of the Gly537Trp variant would result in elevated transcription of HIF-2 target genes. Consequently, these findings support a critical role for HIF-2a in control of Epo production in humans.
Diabetes Impairs Bone Marrow Microenvironment Affecting Progenitor Cell Number, Mobilization and Engraftment in Humans.
Authors: Rizzoli Vittorio , Masselli Elena , Prezioso Lucia , Ferraro Francesca , Lodi-Rizzini Elisa , Mangoni Marcellina , Graiani Gallia , Frati Caterina , Spinetti Gaia , Reni Carlotta , Emanueli Costanza , Emanueli Costanza , Madeddu Paolo , Quaini Federico 
Published: October 2019

Abstract
Abstract 1482
Poster Board I-505
Alterations in cell trafficking and chemoattractive properties may represent basic mechanisms responsible for organ pathology in diabetes mellitus (DM). These functional events involving both inflammatory and progenitor cells may be translated in the proneness to major septic events and effaced reparative response characterizing the clinical course of the disease. To determine whether DM affects BM progenitor cell number and function, tissue resident and GSF mobilized disease-free BM CD34pos cells were evaluated in 19 DM and 38 non-diabetic control (CTR) biopsies and in 18 DM and 48 CTR patients undergoing autologous BM transplantation. DM was documented by the presence of glucose intolerance, HbA1C > 6 g% and need of high dose insulin treatment. CTR were selected on the basis of normal glucose tolerance and the absence of neoplastic infiltration and/or morphologic changes in cellular hematopoietic compartments compatible with hematologic disorders. Reduction in trabecular bone, fat accumulation, rearrangement of microvascular structures and marked DNA oxidative damage characterized BM structural and cellular remodelling in DM. Immunohistochemical and FACS analysis documented that DM produced a 50% reduction in the number of both BM resident and mobilized CD34pos Linneg cells. In addition only 16% of diabetic patients were able to mobilize >10 × 106 CD34pos cells/kg compared to 62% of CTR. After infusion of mobilized CD34pos progenitors, BM engraftment was partially prolonged in diabetic patients. Severe impairment of SC engraftment by DM was striking by the comparative analysis of the infusion of similar number of mononuclear cells (nearly 180 ×106/Kg) directly harvested from the bone marrow of DM and CTR patients. In this setting, PMN and Plts recovery was delayed by nearly 2 and 4 weeks, respectively. Thus, DM severely affects human progenitor cell function and BM microenvronment in vivo inevitably impairing the outcome of BM transplantation. Whether all these changes are due to specific perturbation of the GSF-dependent SDF-1/CXCR4 axis and whether drugs interfering with ROS mediated damage may reverse this phenomenon is under intense investigation.

Disclosures:
No relevant conflicts of interest to declare.
Lenalidomide Shuts Down the Translational Machinery in Multiple Myeloma Cells Resulting in Down-Regulation of Critical Transcription Factors Such as C/EBPβ and IRF4.
Authors: Li Shirong , Pal Rekha , Galson Deborah L , Schafer Peter H , Ouyang Hongjiao , Mapara Markus Y , Lentzsch Suzanne 
Published: October 2019

Abstract
Abstract 1844
Poster Board I-870
Background: Lenalidomide is an immunomodulatory drug that has been shown to be highly active in the treatment of multiple myeloma (MM). In combination with dexamethasone, remission rates of up to 61% are achieved in newly diagnosed MM patients. Nevertheless, the mechanisms of how immunomodulatory compounds induce high remission rates in MM remains elusive. Methods and Results: Here we investigate the underlying anti-MM mechanism of lenalidomide. Lenalidomide significantly (p<0.01) inhibited DNA synthesis at concentrations as low as 0.01 μM in MM.1S or OPM2, as shown by thymidine uptake analysis. Inhibition of proliferation was accompanied by cell cycle arrest at G0/G1 in MM cell lines. Even at high concentrations up to 100 uM lenalidomide did not induce the expected level of apoptosis in MM cell lines. Previously we have demonstrated that C/EBPβ is an important transcription factor which controls growth and proliferation of MM cells and also regulates the transcription of interferon regulatory factor-4 (IRF4). Our present data show that lenalidomide significantly inhibited the protein expression of C/EBPβ in MM cell line and primary MM cells. Furthermore, we found that lenalidomide does not decrease the mRNA level of C/EBPβ, nor induce the protein degradation of C/EBPβ, suggesting that the protein translation of C/EBPβ was inhibited. Consistent with this notion, analysis of the effects of the compounds on the translational machinery in MM cells revealed that the protein eukaryote initiation factor 4E (eIF4E) was significantly down-regulated in both lenalidomide-treated MM cell lines and primary MM cells. The resulting decreased C/EBPβ protein expression impaired the transcription of downstream IRF4, BLIMP1 and XBP1, which are all critical for MM survival. Conclusions: Our studies, for the first time, provide evidence that lenalidomide inhibits MM cell proliferation and survival by likely inhibiting the protein translation of C/EBPβ and consequently repressing gene expression of multiple downstream transcription factors of C/EBPβ including IRF4, BLIMP1 and XBP1.

Disclosures:
Schafer: Celgene Corporation: Employment. Lentzsch:Celgene: Consultancy, Speakers Bureau; Pfizer: Consultancy.
Cell Specific Consequences of Notch Signaling: PARP1/HES1 Interaction Reveals a Novel Tumor Suppressor Mechanism.
Authors: Kannan Sankaranarayanan , Zweidler-McKay Patrick A. 
Published: October 2019

Abstract
Abstract 2388
Poster Board II-365
The Notch signaling pathway is a critical regulator of cell fate determination and differentiation during development, which is highly cell type specific. Similarly, Notch signaling plays both oncogenic and tumor suppressor roles in a wide variety of malignancies, depending on cell type. In contrast to T cell acute lymphoblastic leukemia (T-ALL) where Notch activation promotes leukemogenesis, induction of Notch signaling in B-ALL leads to growth arrest and apoptosis. The Notch target gene Hairy/Enhancer of Split1 (HES1) is sufficient to reproduce this tumor suppressor phenotype in B-ALL, however the mechanism is not yet known.
Here we report the novel finding that HES1 forms distinct complexes in B-ALL versus T-ALL. This suggests that HES1 interacting proteins may contribute to the cell-type specific consequences of Notch/HES1 signaling. During characterization of these complexes, we identified the novel interaction between HES1 and PARP1 through immunoprecipitation and MALDI-TOF protein sequencing. This interaction was dependent on the HES1 bHLH and Orange domains and PARP1 and HES1 co-localize to a genomic HES1 binding site by ChIP. This interaction both inhibits HES1 repressor function and induces PARP1 activation in B-ALL. HES1-induced PARP1 cleavage leads to enhanced poly ADP ribosylation of PARP1, consumption of NAD+, diminished ATP levels, and translocation of the Apoptosis Inducing Factor (AIF) from mitochondria to the nucleus, resulting in apoptosis in B-ALL, but not T-ALL. Importantly the potential therapeutic Notch agonist peptide “DSL” also induces cell-specific growth arrest and apoptosis (A+B), followed by poly-ADP ribosylation of PARP1 (C), and nuclear translocation of AIF in B-ALL but not T-ALL cells (D).
These data reveal a novel interaction of HES1 and PARP1 in B-ALL which modulates the function of the HES1 transcriptional complex and signals through PARP1 to induce apoptosis. This novel tumor suppressor mechanism involving a Notch driven, cell-type specific pro-apoptotic pathway may lead to the development of Notch agonist-based cancer therapeutics.

Disclosures:
No relevant conflicts of interest to declare.
Glanzmann's Thrombasthenia Mutation of the Genes ITGA2B and ITGB3.
Authors: Corinaldesi Giorgio , Corinaldesi Christian 
Published: October 2019

Abstract
Abstract 2411
Poster Board II-389
Glanzmann Thrombasthenia (GT) is a rare autosomal recessive bleeding disorder characterized by a life-long mucocutaneous bleeding tenedency and absence or severely reduced platelet aggregation in response to ADP, epinephrine, and collagen, but relatively normal in response to ristocetin, where the glycoprotein (GP) IIb/IIIa a calcium dependent heterodimer complex is deficient or present but dysfunctional. GPIIb 172kbp is composed of 30 exons and GPIIIa 65Kbp is composed of 15 exons, have their own separate genes on the long arm of chomosome 17 (17q21-32), specific genetic abnormalities of each GP include missense, non sense, splite site mutation, deletions and point mutation. Mutation abrogates ligand binding to the activate integrin to the adhesive protein: fibrinogen, vWF, fibronectin, vitronectin, CD40L and the platelet are unable to mediate outside-inside signaling promoting actin plymerization and cytoskeletal reorganization such as clot retraction, talin and kindlin protein activation. We have studied four patients with mutation of the gene encoding platelet GPIIb (ITGAIIB) exon 17 mutation 1750 C (cystein)-T (threonin) phenotype non sense R584X,the proband showed a platelet with 3%-10% a fibrinogen binding and GPIIb/IIIa receptors; exon 23 mutation 2333 A (alanin)-C (cystein) phenotype missense Q778P, produced truncated protein, cystein residue is ipermethylated with a reduction of adhesion <8% cystein is postulated to be critical for post translational processing of GPIIb; and the gene encoding platelet GPIIIa (ITGB3) exon 11 mutation 1813 G (glycin)-A (alanin) phenotype missense H306P,ifluencing the Ca2+ dependent stabilty of the GPIIb/IIIa complex to divalent cation chelation; exon 3 mutation 355 C (cystein)- T (threonin) phenotype missense R119W escluding at codon 355 leader sequence, producing a frame-shift and protein termination and a stop codon with a great abnormalities of GPIIb/IIIa heterodimer inter subunit surface interaction, and intracellular trafficking. The patients have all severe bleeding included epistaxis, petechiae, gum bleeding, and a high grade of relapsing, refractory bleeding often requiring the transfusion with HLA compatible platelet concentrats and/or administration of recombinant FVIIa. This study confirmed that the genetic mutation can be significatly associated with the frequency and severity of bleeding and these approach may be the future of the management of GT.

Disclosures:
No relevant conflicts of interest to declare.
Radioprotection by Mesenchymal Stem Cells Overexpressing Extracellular Superoxide Dismutase.
Authors: Deng Weiwen , Abdel-Mageed Aly S , Senagore Anthony J , Pietryga Daniel W , Connors Robert H , Giambernardi Troy A , Hay Rick V 
Published: October 2019

Abstract
Abstract 4510
Oxidative stress caused by ionizing radiation is a major determinant of radiation injuries. Extracellular superoxide dismutase (ECSOD), a potent antioxidant enzyme, alleviates oxidative stress. Mesenchymal stem cells (MSCs), a subset of adult stem cells from bone marrow, have been found to migrate to radiation injured tissues after intravenous administration. Here, we show for the first time that intravenous administration of MSCs genetically modified to secrete ECSOD improves survival, extends lifespan, retards cataract formation, and prevents carcinogenesis in irradiated mice. These findings suggest that intravenous administration of MSCs overexpressing ECSOD could become a critical medical countermeasure against radiation.

Disclosures:
No relevant conflicts of interest to declare.
Increased Regulatory T Cell Function in a Mouse Model of Beta-Thalassemia.
Authors: Bao Weili , Heck Susanne , He Wu , Yazdanbakhsh Karina 
Published: October 2019

Abstract
Abstract 638
The development of red blood cell (RBC) alloantibodies complicates transfusion therapy for chronically transfused patients with thalassemias. Understanding the regulation of immune responses to transfused RBCs may help in future design of therapeutic interventions to prevent RBC alloimmunization in this patient population. We have previously reported in a mouse model that key immune response regulators, CD4+CD25− regulatory T cells (Tregs) expressing Foxp3, control the rate and frequency of RBC alloimmunization in wildtype recipient mice. As an initial step to study and characterize immune regulation in thalassemias, we studied the Treg status of Hbb(th1/th1) mouse model of beta-thalassemia intermedia, known to exhibit mild anemia, reticulocytosis and splenomegaly. Compared to wildtype littermate controls (WT) (n=11), 3 month old thalassemic (THAL) mice (n=12) had significantly higher frequency of CD25+Foxp3+ Tregs in CD4+ population in peripheral blood (5.5±0.5% versus 4.1±0.3%, p=0.03) but not in the spleen (11.4%±0.9% versus 9.5±0.5%, p=0.1). Sorted splenic Tregs from THAL and WT mice were equally anergic to stimulation through the T cell receptor and Tregs from THAL mice secreted the expected low background levels of IL-2 and IFN-gamma in stimulated culture supernatants, similar to Tregs from WT mice. Surprisingly, however, the THAL stimulated Tregs, but not the WT counterparts, secreted the proinflammatory cytokine IL-17. To determine whether THAL Tregs were functionally active, we performed in vitro Treg suppressive assay. We found that thalassemic Tregs were in fact more suppressive than Tregs from their WT counterparts in their ability to suppress proliferation of CD4+CD25–T cells (at 1:4 ratio of Tregs : CD4+CD25–cells 91±3% thalassemic versus 66±3% WT , p=0.03; at 1:8 ratio, 84±4% % versus 63±7%, p=0.02 and at 1:16 ratio, 76±4% % versus 28±14%, p=0.03).
We next performed red cell transfusion studies to determine if the increased in vitro THAL Treg suppressive activity is associated with decrease in frequency of alloimmunization in THAL mice. A cohort of age- and sex-matched THAL and WT mice were transfused on a weekly basis for 4 weeks with red cells from transgenic mice expressing human glycophorin A. We found that considerably lower (2/9) alloimmunization rates in THAL compared to WT mice (8/11). Altogether, our data indicate that qualitative differences exist between Tregs from THAL mice and their littermate controls and raise the interesting possibility that THAL Tregs may represent a novel population of Tregs. Specifically, only THAL Tregs secrete the proinflammatory cytokine IL-17 normally associated with Th17 subset and yet they are functionally more suppressive. The mechanisms responsible for these differences are under further study.

Disclosures:
No relevant conflicts of interest to declare.