bluuebunny/crossref_metadata_2025_split huggingface dataset:
Temporal Incidence Trends of Pediatric Venous Thromboembolism: A Population-Based Cohort Study
Authors: Sabapathy Christine A. , Kahn Susan R. , Platt Robert W , Tagalakis Vicky 
Published: October 2019

Abstract
Abstract 1138

Background:
Pediatric venous thromboembolism (VTE), although rare, is associated with significant morbidity and mortality. Published incidence rates in this age group vary from 0.07 to 0.49 VTE per 10 000 children/year and there is currently a paucity of studies evaluating temporal incidence trends.

Objectives:
To describe the age-adjusted incidence rates of pediatric VTE and its trend over time in a large pediatric cohort.

Methods:
A retrospective cohort of all children (ages 1–17 inclusive) with a first time diagnosis of VTE in the province of Quebec, Canada over an eleven-year period, from January 1st, 1994 to December 31st, 2004, was obtained from a comprehensive administrative hospital database (Med-Echo). Quebec census estimates were used to calculate age-standardized incidence rates (IR) of pediatric VTE. The incidence rate trend was then analyzed over the eleven-year study period using Poisson linear regression. Sex differences in incidence rates at the population level stratified by age group as a confounder as well as baseline characteristics of the cases were also evaluated.

Results:
In total, 487 incident cases of VTE in children 1–17 years of age were documented during the study period. Based on the estimated provincial census person-years during the study period, the age-standardized IR was 0.29 VTE per 10 000 person-years (95% confidence interval (CI) 0.26–0.31). Females overall had a statistically significant higher VTE incidence rate with an incidence rate ratio of 1.75 (95% CI 1.46–2.11) when controlled for age groups, as compared to males. When analyzed by age group, the age-standardized IRs were as follows: 1–5 year olds 0.04 VTE per 10 000 person-years (95% CI 0.03–0.05); 6–10 year olds 0.03 VTE per 10 000 person-years (95% CI 0.02–0.04); 11–14 year olds 0.06 VTE per 10 000 person-years (95% CI 0.05–0.07); 15–17 year olds 0.16 VTE per 10 000 person-years (95% CI 0.14–0.18).
Trend analysis of the age-standardized IRs over the 11-year period showed no significant change in incidence rates whether using time as a continuous (yearly) or categorical variable (time-periods).

Conclusions:
Pediatric VTE is more frequent than previously described, however the rate is stable. As shown by others, children in their late-teen years have a higher risk of VTE than primary school-aged children. Unlike prior studies, females were more prone to VTE than males. Future studies that address sex differences in the incidence of pediatric VTE are needed to help determine effective primary thromboprophylaxis strategies in children at high risk for VTE.

Disclosures:
No relevant conflicts of interest to declare.
Single Nucleotide Polymorphisms (SNPs) Associated with Pulmonary Embolism (PE): A Genome-Wide Association Study (GWAS)
Authors: Heit John A , Armasu Sebastian M. , de Andrade Mariza 
Published: October 2019

Abstract
Abstract 1148

Background:
Factor V Leiden (F5rs6025) has been suggested as a disease-susceptibility SNP for deep vein thrombosis (DVT) but not PE. Given the significantly reduced survival after PE, identifying individuals at risk for PE is important for targeting prophylaxis and improving survival.

Objectives:
To identify PE disease-susceptibility genes.

Methods:
We performed in silicoGWAS analyses of VTE cases using genotype data imputed to ∼2.5 million SNPs from adults with objectively-diagnosed PE ± DVT (n=745), and DVT only (n=758). We tested these SNPs for an association with PE ± DVT after adjusting for age, sex, stroke and/or myocardial infarction, and USA state of residence using unconditional logistic regression.

Results:
Of all SNPs, three were most strongly associated with PE ± DVT: one at BDH1 on chromosome (chr) 3q29 (rs1309873, OR=1.56, p=4.02E-07) and two at SLC39A10 on chr 2q32.3 (rs7578216, OR=2.55, p=4.57E-07; and rs4589778, OR=2.49, p=7.52E-07). Individually adjusting for F5 rs6025 (chr 1), F2 rs1799963 (prothrombin G20210A; chr 11) and ABO rs8176719 (ABO blood type O allele; chr 9) did not materially affect these associations. None of these three SNPs associated with PE were intragenic. BDH1 encodes for 3-hydroxybutyrate dehydrogenase 1, a key mitochondrial enzyme in fatty acid catabolism, and SLC39A10encodes for solute carrier family 39, member 10, an important protein for zinc transport.

Conclusions:
Chromosomes 3q29 (BDH1) and 2q32.2 (SLC39A10) may harbor PE disease-susceptibility gene regions (genes). These findings require independent confirmation. If confirmed, additional studies addressing the biologic mechanisms through which these genes and/or gene regions operate to increase PE risk also will be required.

Disclosures:
No relevant conflicts of interest to declare.
Tolerated, Low-Dose Deferasirox: Successful Three Cases of Aplastic Anemia and 34 Cases of MDS
Authors: Hirai Manabu , Yamamura Ryousuke , Nakamae Hirohisa , Terada Yoshiki , Inoue Atsushi , Hashimura Mitsuharu , Ichihara Hiroyoshi , Sakamoto Erina , Hino Masayuki 
Published: October 2019

Abstract
Abstract 1187
It has been shown that serum ferritin (SF) levels are associated with mortality in transfusion-dependent patients with MDS. Optimal dosing with deferasirox has been shown to decrease SF level even in transfusion-dependent patients and to be able to decrease the adverse effects of repeated transfusion. Previous studies have however shown that about 50% of patients withdraw from treatment because of side effects in the early phase of treatment.
Low-dose deferasirox (mean 6.3 mg/kg, range 1.6∼25.6) was administered to 53 patients (MDS 34, AA 13, ALL 2, MF 2, AML 1,ML 1) with dose escalation up to the maximum dose tolerated (mean 9.8 mg/kg, range 1.6∼31.0). In 47 eligible cases, a mean SF of 1579 ng/ml (range 320∼4477) decreased to 1101 ng/ml (range 233∼1680) at 18 months with 71% of continuous rate. Just six cases had treatment stopped, solely because of renal dysfunction. In three cases with transfusion-dependent aplastic anemia, deferasirox (6.25∼10.8 mg/kg) was given with G-CSF, cyclosporin A, and metenolone with the successful abreaction from transfusion dependency and even with elevation of the platelet count (from 10 to 30∼50×109/L).
Continuous administration of low-dose deferasirox, as tolerated, was thought to be sufficient to prevent a rise in SF in transfusion-dependent patients. A prospective study that will examine OS in such MDS patients has been started.

Disclosures:
No relevant conflicts of interest to declare.
Rescue of the HSC Maintenance Defects in Ku70-Deficient Mice by Overexpression of Bcl2 Reveals a Novel Role of Bcl2 in HSC
Authors: Qing Yulan , Wang Zhengqi , Matsuyama Shigemi , Bunting Kevin D. , Gerson Stanton L. 
Published: October 2019

Abstract
Abstract 1235
Ku70 is a key component of the non-homologous end joining (NHEJ) pathway; Ku70-deficient mice are hypersensitive to radiation and show a leaky SCID phenotype. We find that HSC from Ku70-deficient mice are severely impaired in maintenance, defective in self-renewal, competitive repopulation and BM hematopoietic niche occupancy. HSCs from Ku70-deficient mice are not prone to spontaneous apoptosis, however, they display more active proliferation, and fewer cells in a quiescent state than HSC obtained from WT mice. Further, gene expression profiling showed that multiple HSC quiescence- related genes such as c-MPL and p57 were significantly downregulated in Ku70-deficient HSCs. These data suggested that loss of quiescence results in the dramatic defect in the maintenance of Ku70-deficient HSC.
Bcl2 plays important roles in both anti-apoptosis and anti-proliferation, while the anti-apoptosis function of Bcl2 has been extensively studied and well established in various settings, including HSCs, the anti-proliferation function of Bcl2 in HSC has yet to be investigated. To exam whether overexpression of Bcl2 can rescue the HSC defect in Ku70-deficient mice, H2K-Bcl2 transgenic/Ku70-deficient double mutant mice were generated. Though overexpression of Bcl2 does not rescue the SCID phenotype in Ku70-deficient mice, overexpression of Bcl2 in Ku70-deficient HSCs almost completely rescued the impaired HSC quiescence, repopulation and BM hematopoietic niche occupancy capacities. At the transcriptional level, overexpression of Bcl2 restored the expression of c-MPL and p57 comparable to WT levels. However, additional deletion of Bax, a pro-apoptosis protein in the Bcl2 family, in Ku70-deficient mice could not rescue the HSC repopulation defect, suggesting that apoptosis is not the main mediator for the impaired HSC maintenance in Ku70-deficient mice.
Together, our data indicate that the HSC maintenance defect of Ku70-deficient mice is due to the loss of HSC quiescence populations, whereas overexpression of Bcl2 rescues the HSC defect in Ku70-deficient mice by restoration of quiescence. Our study uncovers a novel role of Bcl2 in hematopoietic stem cell quiescence regulation.

Disclosures:
No relevant conflicts of interest to declare.
Neuromedin U Peptide Activates STAT5 and S6 in a JAK-2 Dependent Manner and Promotes Erythroid Cell Growth in Primary Erythroid Progenitor Cells
Authors: Lenzo Rebecca , Dua-Awereh Martha , Carroll Martin , Shetzline Susan E. 
Published: October 2019

Abstract
Abstract 1241
Erythropoiesis is a multi-step process during which hematopoietic stem cells terminally differentiate into red blood cells (RBCs). Erythropoietin (EPO) is the only known cytokine regulator of terminal erythroid differentiation. Previously, we reported that the neuropeptide, neuromedin U (NmU), which interacts with NmU receptor type 1 (NMUR1), functions as a novel extracellular cofactor with EPO to promote the expansion of early erythroblasts, which are CD34−, CD71+, glycophorin A (GlyA)dim(Gambone et al, Blood. 2011). Here, we describe studies to understand the mechanism whereby NmU augments EPO effects on erythroid cell growth. EPO triggers Janus kinase (Jak)-2 dependent activation of signal transducer and activator of transcription (STAT) 5 and phosphatidylinositol 3-kinase (PI3K) to promote the proliferation and/or survival of erythroid progenitor cells. We hypothesized that NmU peptide would cooperate with EPO to promote the proliferation of early erythroblasts through STAT5 and/or PI3K activation. To address this hypothesis, we cultured primary human CD34+ cells in 2-stage liquid culture with IL-3, IL-6, and stem cell factor (SCF) from day 0 to day 6. On day 6, 2U/mL of EPO was added, and the cells were cultured for an additional 5 days to expand erythroid progenitors. On day 11, cells were briefly serum starved and then stimulated with EPO and/or NmU in the absence or presence of a Jak-1/2 inhibitor. Activation of STAT5 and S6, a surrogate marker for PI3K activation, were assessed by phospho-flow in ERY3 (CD34−, CD71+, GlyA+) and ERY4 (CD34−, CD71dim, GlyA+) cells. As expected, EPO alone activated STAT5 and S6 in ERY3 cells only, and the presence of a Jak-1/2 inhibitor diminished STAT5 activation. Interestingly, STAT5 and S6 were activated by NmU peptide alone in ERY3 and ERY4. Surprisingly, in the presence of a Jak-1/2 inhibitor, NmU peptide, which binds to NMUR1 a G-protein coupled receptor, did not activate STAT5 or S6 in ERY3 or 4 cells, suggesting that NmU functions through a JAK kinase in erythroid cells. No additive or synergistic activation of STAT5 and S6 is observed in the presence of both EPO and NmU peptide when EPO was used at a dose of 2 U/mL. The mechanism whereby NmU activates a JAK dependent signaling pathway is under investigation. Preliminary evidence suggests that EPO induces the physical association of NMUR1 with EPO receptor (EPOR). Taken together, we propose that NmU is a neuropeptide expressed in bone marrow cells that cooperates to regulate erythroid expansion during early erythropoiesis through the activation of cytokine receptor like signaling pathways and perhaps through direct interaction with EPOR. NmU may be useful in the clinical management of anemia in patients unresponsive to EPO or other erythroid-stimulating agents.

Disclosures:
No relevant conflicts of interest to declare.
Identifying an Acetylation Signature Following Vorinostat Treatment in AML
Authors: Hay Jodie F , Liberante Fabio G , McCourt Clare , O'Hagan Kathleen A , Mills Ken I 
Published: October 2019

Abstract
Abstract 1291
Acute myeloid leukemia (AML) remains incurable for most patients, particularly in the elderly, and novel therapeutic approaches are needed. Genes are often epigenetically silenced in AML through the recruitment of histone deacetylases (HDACs) and the development of agents that inhibit HDACs (HDACi) are a novel treatment approach to AML. However, AML represents a spectrum of mutations and chromosomal abnormalities and it would be of benefit to target these therapies based on epigenetic profiles and responses. One HDAC inhibitor, Vorinostat (Zolinza™), is currently being used in phase i/ii clinical trials as a therapeutic strategy in multiple myeloma with evidence that combinational therapies provide an extended disease free survival; this could be an attractive option for AML. In order to find a successful combination, a fuller characterisation of Vorinostat induced histone modifications is required.
In this study, we used a combination of ChIP-seq and microarray approaches to identify epigenetically silenced genes pathways in AML cells that could be restored by treatment with the HDACi Vorinostat.
OCI-AML3 cells were treated with Vorinostat 1 μM or control conditions for 24 hours. Changes in gene expression were measured using Affymetrix Human Genome U133 Plus 2.0 and/or Leukemia AmpliChip arrays. The ChIP-seq was done on DNA extracted from the same cells and time points as for the expression study. The chromatin was cross-linked and the protein-DNA interactions at H3K9Ac were elucidated by chromatin immunoprecipitation, with anti-acetylated H3K9 histone and Pol II antibodies. Pol II was used to identify regions of actively transcribed DNA, and high throughput sequencing using the Ion Torrent PGM (Life Technologies).
After treatment with Vorinostat, expression studies showed that 180 genes were up-regulated and 441 genes were down-regulated (FC 4, p<0.05). The ChIP-seq data identified DNA sequences that were associated with de-acetylated histones following Vorinostat treatment. Bioinformatic analysis identified regions that were also associated with actively transcribed regions of DNA. Pathway analysis identified that the principle pathways induced by Vorinostat were TGFβ signalling and glycosaminoglycan degradation. Gene set enrichment analysis showed that Vorinostat down-regulated the integrin mediated signalling and p53 binding, and up-regulated stem cell differentiation, blood vessel morphogenesis and response to fibroblast growth factor stimulus.
This study would indicate that Vorinostat is an effective regulator of gene expression in AML cells and that the integrated approach can identify specific epigenetic targets of Vorinostat and could lead to the development of tailored AML therapies.

Disclosures:
No relevant conflicts of interest to declare.
Notch/HES1 Signaling Stabilizes p53 Expression Via a Novel PARP1-Chfr-PLK1-Mediated Mechanism in B-ALL
Authors: Kannan Sankaranarayanan , Zweidler-McKay Patrick A 
Published: October 2019

Abstract
Abstract 1292

Background:
Notch signaling contributes to T cell leukemogenesis. However, we have found that activation of Notch signaling in human B-ALL promotes growth arrest and apoptosis. These contrasting effects of Notch in B versus T cell ALL, mirror effects seen in early lymphocyte development. As the Notch receptors are common between T and B cells, we hypothesized that these differences rely on the cell-type specific downstream mechanisms. We previously reported a critical role for Notch/HES1-mediated activation of Poly ADP-Ribose Polymerase 1 (PARP1) function in this B cell specific mechanism.

Approach:
To explore the cell-type specific downstream mechanisms of Notch activation in B-ALL, we used cell fractionation, westerns and immunoprecipitation to identify cell cycle regulators which were altered by Notch activation via HES1 expression in human B-ALL lines.

Results:
Notch activation in a panel of human B-ALL lines led to consistent growth arrest and apoptosis. Indeed, ligands, activated receptors and the Notch target gene HES1 all induced these leukemia lihibiting effects in B-ALL but not T-ALL lines. In this study we report a mechanism whereby HES1-mediated activation of PARP1 leads to PARylation of the E3 ligase Checkpoint with FHA and RING finger (CHFR) (Panel A) which results in targeting and ubiquitination of the cell cycle regulator Polo-Like Kinase 1 (PLK1) (Panel B). PLK1 is highly expressed in B vs. T-ALL and plays a critical role in B cell growth and survival. Following Notch activation, loss of ubiquitionated PLK1 through proteosomal degradation leads to cell cycle arrest through two mechanisms, namely cytoplasmic relocalization of cyclin B, disrupting the CDC2-cyclinB complex, as well as phosphorylation of p53 at S20, which leads to decreased weakened p53-MDM2 interaction and accumulation of p53 (Panel C). siRNA to CHFR reveal that this mechanism is dependent on CHFR (Panel C). Importantly this mechanism is not seen in T-ALL cells as the activation of PARP1 by HES1 does not occur in T-ALL cells.

Conclusions:
Our findings reveal a novel molecular mechanism whereby Notch signaling induces disruption of the cell cycle in a cell type specific manner in B-ALL. Activation of PARP1, PARylation of CHFR, ubiquitination of PLK1 resulting in loss of nuclear cyclin B and accumulation of p53 demonstrates a series of events which can be initiated through activation of Notch in B-ALL. This mechanism reveals a potentially targetable approach to B-ALL.

Disclosures:
No relevant conflicts of interest to declare.
TET2, ANPM1 and FLT3-ITD Gene Mutations in Normal Karyotype Acute Myeloid Leukemia
Authors: Sun Aining , Tian Xiaopeng , Yin Jia , Li Weiyang , Chen Suning , Depei Wu 
Published: October 2019

Abstract
Abstract 1413

Objective:
Analyze the molecular genetics characteristics of acute myeloid leukemia with normal karyotype and explore the relationship between different genetic mutation patterns and prognosis.

Methods:
A total of 373 acute myeloid leukemia (AML) with normal karyotype diagnosed and treated in the First Affiliated Hospital of Soochow University from 2005 to 2010 were recruited in this research to assess the genetic mutation patterns. The target genes which was extracted from bone marrow cell were amplified by PCR and analyzed by massively DNA sequencing. All of the TET2, DNMT3A, IDH1, IDH2, EZH2, CBL, ASXL1, MLL-PTD, NPM1, WT1, RUNX1, c-KIT, FLT3-ITD, FLT3-TKD, N-RAS and JAK2V617F gene mutations were detected in our study.

Results:
(1). A total of 16.1% of patients had TET2 mutations, 31.6% had FLT3 internal tandem duplications (ITDs), 6.2% had FLT3 tyrosine kinase domain mutations, 2.4% had c-KIT mutations, 37.8% had NPM1 mutations, 11.3% had WT1 mutations, 5.9% had RUNX1 mutations, 11.5% had ASXL1 mutations, 3.8% had MLL partial tandem duplications (PTDs), 7.8% had IDH1 mutations, 7.8% had NRAS mutations, 12.3% had IDH2 mutations, 1.6% had EZH2 mutations, 14.7% had DNMT3A mutations and no mutations were found of CBL and JAK2V617F. In conclusion, there are 77% (287/373) gene mutations hide in normal karyotype AML patients.(2). We found that the TET2 gene mutations were associated with DNMT3A (P = 0.041) and RUNX1 (P <0.001) mutations, but mutually exclusive with IDH2 (P = 0.021), or IDH1/2 (P = 0.006) gene mutations. NPM1 gene mutations were highly correlated with DNMT3A mutations (P <0.0001), IDH1 mutations (P <0.0001) and IDH2 mutations (P = 0.001), but mutually exclusive with RUNX1 mutations (P=0.003). IDH2 mutations and WT1 mutations were mutually exclusive (P = 0.01); DNMT3A mutations were associated with NRAS mutations (P = 0.01). In addition, study have shown that the number of gene mutations was closely associated with older age, high white blood cell and high bone marrow blast cell percentage, but wasn't correlated with gender, hemoglobin and platelet levels.(3). In the NPM1m+ patients, TET2 mutations were associated with shorter median OS in contrast to TET2 wild type (9.9 vs. 27.0 months, P= 0.023). Surprisingly, in NPM1m+/FLT3-ITDm- group, TET2 mutations was also an unfavorable prognostic factor, which was closely associated with shorter median OS compared to TET2 wild type (9.5 vs. 32.2 months, P=0.013).

Conclusion:
Gene mutations incidence was high in normal karyotype AML patients. TET2 mutations was an unfavorable prognostic factor which was closely associated with shorter median OS in contrast to TET2 wild type in NPM1m+/FLT3-ITDm-group. In addition, The number of gene mutation was closely associated with older age, high white blood cell levels and high bone marrow blast cell percentage.

Disclosures:
No relevant conflicts of interest to declare.
Lenalidomide Consolidation Followed by Maintenance After Autologous Transplantation for Multiple Myeloma Decreases Thymic Output and Terminally Differentiated CD4 and CD8 T Cells but Increases Treg
Authors: Clave Emmanuel , Douay Corinne , Coman Tereza , Busson Marc , Bompoint Caroline , Moins Helene , Carmagnat Maryvonnick , Gorin Norbert Claude , Charron Dominique , Toubert Antoine , Garderet Laurent 
Published: October 2019

Abstract
Abstract 4046
Treatment with lenalidomide, an immunomodulatory drug, increases the time to progression in relapsed/refractory multiple myeloma. However, due to its pleiotropic effect, it is not known whether the efficacy of this drug is due only to direct tumor toxicity or also to immunomodulatory effects. We assessed in vivo the changes in T-cell reconstitution induced by lenalidomide consolidation and maintenance treatment following autologous peripheral blood stem cell transplantation (ASCT) in a cohort of multiple myeloma patients.
Twenty-nine newly diagnosed myeloma patients were treated with the induction combination bortezomib plus dex followed by high dose melphalan (140–200 mg/m2) and ASCT. A first group of 11 patients were treated with lenalidomide consolidation initiated 3 to 6 months post transplantation: 25 mg/day, days 1–21 of a 28 day cycle for 2 months, followed by maintenance (10 mg/day) until disease progression. This group was compared with the 18 patients who did not receive any treatment after ASCT. Blood samples were collected at diagnosis, before the transplant and 1, 3, 6, 9, 12 and 18 months after ASCT. Thymic function was assessed by real-time PCR quantification of T cell receptor excision circles (sjTREC) and percentages and absolute counts of T lymphocyte subpopulations were determined by multicolor flow cytometry. Statistics were performed using the Log-Rank or Mann-Whitney test.
The two cohorts had similar baseline characteristics and all 29 patients were in remission after ASCT. With a median follow-up of 4 years, progression-free survival (PFS) was superior with lenalidomide treatment (69% vs 36%, p=0.05) while overall survival (OS) was similar (82% vs 75%, p=0.5). Lenalidomide treatment induced a progressive decrease in sjTREC (median at 18 months, 0.25/μL vs 1.61/μL, p<0.05) and a decrease in the percentages and absolute counts of CD4+ and CD8+ CD45RA+CCR7- effector terminal T cell subpopulations (median at 18 months, 3.2/μL vs 17.6/μL, p<0.05 for CD4+CD45RA+CCR7- and 109/μL vs 345/μL, p<0.05 for CD8+CD45RA+CCR7-). Conversely, lenalidomide treated patients displayed an increase in CD4+CD25+CD127-/low Treg populations, in both percentage and absolute count (median 13% vs 8 %, p<0.05 and 48.9/μL vs 29.3/μL, p<0.05, respectively). No correlation was found with documented infections, relapse or survival.
We confirm an increase in PFS with lenalidomide consolidation/maintenance following ASCT. However, our data also suggest that in myeloma patients, the effect of lenalidomide on the myeloma tumor may not be T cell mediated and this treatment may have a negative impact on the T cell immune surveillance.

Disclosures:
No relevant conflicts of interest to declare.