bluuebunny/crossref_metadata_2025_split huggingface dataset:
An In Vivo Genome-Wide CRISPR Screen Identifies Novel Dependencies for Blast Crisis Chronic Myelogenous Leukemia
Authors: Bajaj Jeevisha , Scott-Browne James , Spinler Kyle , Reya Tannishtha 
Published: October 2019

Abstract
Poorly differentiated aggressive myeloid diseases such as Acute Myelogenous Leukemia (AML) and blast crisis Chronic Myelogenous Leukemia (bcCML) are often resistant to standard therapy and associated with significantly poor survival in both children and adults. There is thus a significant need for a better understanding of the mechanisms that drive disease progression and for finding novel therapeutic targets. Thus, to determine the molecular effectors of myeloid leukemia growth in vivo, we carried out a genome-wide CRISPR/Cas9 dropout screen using the lentiviral Brie gRNA library. This library targets 19,674 genes, and has on average 3 gRNAs for each gene, and 1000 control non-targeting gRNAs. We carried out this whole-genome screen in a mouse model of Cas9+ blast crisis CML (bcCML) driven by BCR-ABL/ NUP98-HOXA9 since this represents a very aggressive phase of myeloid cancer where 90% of the leukemic blasts are undifferentiated and cancer stem cell-like. This in vivo screen led to the identification of 3636 genes essential for leukemic growth and propagation in the bone marrow of recipient mice, constituting pathways such as metabolism, protein translation and DNA replication. The genes that were significantly depleted included known drivers of myeloid cancer progression and regulators of myeloid cancer stem cells (for example, Brd4, Kdm1a, Pafah1b1/Lis1, Rptor), indicating that our screening strategy can successfully identify functional drivers of cancer growth.
While intrinsic signals that drive myeloid cancer progression are well described, little is known about how interactions with the surrounding microenvironment can control leukemic growth and propagation. Our whole-genome screen identified ~130 cell surface genes that are significantly depleted in the bcCML stem cells transplanted in vivo. Since environmental factors commonly signal through receptors on the surface of leukemic cells, this subset is likely to include most, if not all, genetic effectors of niche driven signals required for in vivo growth and propagation of aggressive myeloid leukemia cells. Of these 130 genes, several have earlier been shown by us and others to be essential for myeloid cancer progression including Itgb1, Cxcr4 and Cd44. We are currently testing the functional contribution of novel candidate cell surface molecules, which can integrate signals from the environment, on the in vivo growth and progression of myeloid malignancies. We anticipate that these studies will provide a basis for testing antibody-mediated therapeutic inhibition of specific microenvironmental signals on myeloid leukemia growth and propagation.

Disclosures
No relevant conflicts of interest to declare.
The Effect of Health Care Disparities on Complications and Mortality in Sickle Cell Disease
Authors: Perimbeti Stuthi Pavani , Hou Kevin Ye , Ramanathan Sabarina , Woodard Adonas , Kyung Daniel , Wang Qian , Crilley Pamela Ann , Ward Kristine , Styler Michael 
Published: October 2019

Abstract
Introduction:
Sickle cell disease (SCD) is a chronic and debilitating disorder that affects approximately 100,000 Americans and results in the development of significant complications, leading to high numbers of hospitalizations, healthcare cost and mortality. Despite the advent of newer therapies, the overall rate of complications has continued to rise. We aimed to study the prevalence of complications in SCD as well as its relation to differing insurance status.
Methods:
Patients with SCD were identified using ICD-9 codes 2826, 28260, 28261, 28262, 28263, 28264, 28268 and 28269 from the Healthcare Cost and Utilization Project's Nationwide Inpatient Sample from 1999 to 2014. Admission with acute chest syndrome, acute myocardial infarction (AMI), avascular necrosis of the hip (AVN), end stage renal disease (ESRD), pneumococcal infections, splenic sequestration and stroke. Univariate and bivariate analyses were performed using the Chi square test. Cox proportional hazard regression was used to control for multiple confounders in calculating the hazard ratios of an event occurrence and mortality.
Results:
A total of 216,438 (Weighted=1,066,536) observations were identified from the years 1999 to 2014. The median age for male patients was 25 years and that for females was 27. Observing the trends from 1999 to 2014, the prevalence of acute chest syndrome increased from 1.22% to 8.82% (p=0.002), splenic sequestration from to 0.08 % to 1% (p=0.01) and AVN from 1 % to 8.8% (p=0.001). The prevalence of stroke and ESRD were unchanged over the interval studied. After controlling for confounding factors such as race, age, sex, income, comorbidities and insurance status, the hazard ratio of mortality for various complications is significantly elevated. Also, after controlling for multiple confounders, the patient's insurance status plays a significant role in the risk of developing a complication and subsequent mortality (Table 1).
Discussion:
The data indicates that the rate of complications from SCD have risen since 1999. With newer therapies and better understanding, the life expectancy of SCD patients has risen over time, nearly doubling from 1951 to 2018. The increased frequency of complications may be attributed to better survivorship and a rising number of older SCDs patients. However, our data also suggests that insurance status plays a significant role in the complication rate of SCD. The uninsured and patients with Medicaid have significantly increased risk of developing disease complications and resultant mortality. This could be the result of reduced access to care and health disparities due to race, socioeconomic status and insurance status.

Disclosures
No relevant conflicts of interest to declare.
Single-Cell RNA-Seq Analysis of Native Murine Megakaryocytes from Young and Old Mice Reveals Significant Metabolic and Mitochondrial Differences throughout Megakaryocyte Development
Authors: Davizon-Castillo Pavel , Jones Kenneth L. , Trahan George D , Di Paola Jorge 
Published: October 2019

Abstract
Traditional transcriptome analysis of megakaryocytes relies on ex-vivo culture and expansion of hematopoietic cells in thrombopoietin-rich media for several days prior to RNA isolation for bulk RNA-seq analysis. This approach has been widely used, however, it is not clear as to what extend this ex vivo expansion of megakaryocytes represents the transcriptome landscape of megakaryocytes at the time of harvest from the bone marrow. In order to get a more detailed megakaryocytic transcriptome landscape immediately after bone marrow harvest, we have optimized a method to perform single cell RNA-seq analysis of native freshly isolated bone marrow megakaryocytes. This was accomplished throughout a series of steps to enrich murine bone marrow for megakaryocytes followed by cell capture using the 10X Genomics platform. In order to assess the transcriptome of native murine megakaryocytes and the effect of age on transcriptional signatures we performed single cell RNA seq analysis of 3 young mice (age 2-3 months old) and 3 old mice (>18 months old). Bioinformatics analyses identified seven transcriptionally different clusters of cells that represent the megakaryocyte ploidy status (Figures 1 and 2). Within these seven regions, 3 of them appear to represent late states of maturation (regions 5, 6 and 7) and possibly, the pro-platelet forming groups of cells due to the elevated expression of megakaryocyte transcripts such as Vwf, Pf4, Itga2b, Itgb3, Gata-1 and Mpl. Ingenuity pathway analysis (IPA) shows that the top three differentially regulated pathways between megakaryocytes from young and old mice are: a) protein ubiquitination; b) mitochondrial dysfunction and; c) oxidative phosphorylation. Furthermore, we validated the RNA-seq analysis at the protein level by measuring ALDHA1 from platelet lysates, the top differentially expressed transcript between groups. Finally, platelets from old mice have a distinctive mitochondrial phenotype characterized by elevated mitochondrial mass and significantly elevated oxygen consumption upon activation by thrombin, features that might be directly contributing to platelet hyperreactivity of aging. In summary, we present a novel methodology to study the transcriptional profile of native megakaryocytes. This initial approach highlights that metabolic and mitochondrial pathways appear to be important modulators of megakaryocyte and platelet development and function.

Disclosures
No relevant conflicts of interest to declare.
Chronic Myeloid Leukemia in Adolescents and Young Adults Treated with Generic Form of Imatinib in Resource Limited Setting: A Single Center Experience from Myanmar
Authors: Han Yin Nwe , Gyi Aye Aye , Htut Khin Thida 
Published: October 2019

Abstract
Chronic myeloid leukemia (CML) is an acquired myelo-proliferative disorder characterized by the presence of BCR-ABL1 fusion transcript with deregulated tyrosine kinase activity. Leukemias are one of the leading causes of cancer related deaths in adolescents and young adults (AYA) particularly in resource limited countries. Recent democratic government in Myanmar holds supportive policies for treatment of cancers in younger population and subsidizes some therapies including imatinib mesylate, a selective BCR-ABL 1 tyrosine kinase inhibitor, although there is still limitation for cytogenetic and molecular monitoring of therapy. This study on response to imatinib in newly diagnosed chronic phase CML was carried out during January 2016 to February 2018 at the North Okkalapa General and Teaching Hospital of Yangon, Myanmar where molecularly confirmed new CML in chronic phase were treated with generic form of imatinib bought by hospital tender system, Unitinib (United Biotech (P) ltd. India) followed by cytogenetic analysis of bone marrow and molecular detection of BCR-ABL1 transcript from peripheral blood by in house real time PCR machine at one year. They are divided into AYA (aged 15-39 years) and adult age groups (40 years and older) and clinical parameters and response to treatment with imatinib 400mg per day were compared. Among 56 cases (median age of 39.5 years, male to female ratio of 1.5:1), half were AYA (28 of 56) with median age of 28.5 years compared to 50 years in adult group with higher male to female ratio of 3.6:1 in AYA group. Patients in AYA had larger spleen size (11 vs 5.5 cm) and higher median white cell count compared to adults (366 x 109/l vs 224 x 109/l) although initial platelet count, peripheral blood eosinophil, basophil and blast percent and Sokal score were comparable. Additional chromosomal abnormalities were detected in 2 AYA and 3 adults with CML. There was no difference in complete haematologic response at 3 and 12 months between AYA and adults (96.4% vs 96.4% and 92.9% vs 89.3% respectively). At 12 months, complete cytogenetic response of AYA at 67.9% was less than 75.0% of adults, it was statistically not significant. Using in house molecular method although not standardized, 14.3% of AYA and 32.1% of adults were molecularly undetectable at one year. The response of AYA to imatinib in this study was comparable to adults despite having adverse prognostic features and receiving only generic forms of treatment in resource limited setting and it would further help support from authorities for leukemia in younger population.

Disclosures
No relevant conflicts of interest to declare.
Comparison of Rivaroxaban with Argatroban in Heparin Induced Thrombocytopenia Using Historical Controls : A Case-Control Study
Authors: Modi Vivek Suresh , Jatwani Karan , Rajeeve Sridevi , Kakked Gaurav , Patel Hardikumar , Bandyopadhyay Dhrubajyoti , Mannem Siva Krishna 
Published: October 2019

Abstract
Introduction
Heparin-induced thrombocytopenia (HIT) is an uncommon and a serious complication of heparin therapy. Currently, only two intravenous Direct Thrombin Inhibitors (DTI) are approved for its therapy. However, their cost and frequent monitoring make the Direct-Acting Oral Anticoagulants (DOACs) an attractive option for its treatment. Several case series and systematic reviews have been published with positive results for use of NOACs in HIT. No head to head trials comparing NOACs and DTI have been published as infrequency of cases make such a study prohibitive. The landmark multicenter trials establishing the role of Argatroban in the treatment of HIT used historical controls to establish it's efficacy. In this study, we aim to compare a cohort of patients treated with Rivaroxaban as recruited from prior case series with a historical cohort treated with Argatroban to establish it's safety and efficacy compared to Argatroban.
Methods:
A literature review was done using Embase and Pubmed to find HIT patients treated with Rivaroxaban. A total of 14 publications were found including case studies, case series, and systematic reviews. A database was created of a total of 51 HIT patients treated with Rivaroxaban alone or argatroban followed by Rivaroxaban using all the publications. All the cases were confirmed HIT cases based on Serotonin release assay and/or HIT antibody. Platelet nadir and Platelet count at the start of therapy as noted wherever possible. Patients with known bleeding diathesis and bleeding sites were excluded from both the cohorts. Outcomes were thrombosis after initiation of therapy and bleeding after initiation of therapy. The cohort was compared with a historical cohort of patients treated with Argatroban alone in the paper published by Lewis et al. Chi-square test was done to compare new thrombosis and bleeding during hospitalization.
Results:
No significant difference was found in the rates of new thrombosis (OR: 0.18, CI: 0.02-1.36, p: 0.06). 5% of patients had major bleeding in the argatroban cohort while none of the patients had major bleeding in Rivaroxaban cohort.
Conclusion:
The study indicates that Argatroban is not significantly better in the treatment of HIT in preventing new thrombosis. However, the bleeding complications might be lower with Rivaroxaban therapy compared to Argatroban therapy. The study is limited by less than ideal comparability of cohorts and low power. However, it provides only such evidence of it's kind.
Table. Table.

Disclosures
No relevant conflicts of interest to declare.
Study of Bone Marrow Response to Platelet Transfusion in Severe Traumatic Brain Injury Patients
Authors: Subramanian Arulselvi , Albert Venencia , Agrawal Deepak , Pati Hara Prasad 
Published: October 2019

Abstract
Introduction: SevereTraumatic Brain Injury (TBI) patients are predisposed to secondary brain insults due to thrombocytopenia and coagulopathy, warranting platelet transfusion. Thrombopoietin (Tpo) has been shown to be a physiological regulator of thrombopoiesis. An inverse correlation between Tpo and the circulating platelet has been previously reported for several clinical conditions. Response pattern of Tpo to circulating platelets in TBI patients has not been studied yet. We hypothesised that in severe TBI patients thrombopoiesis response to TPO will be impaired
Methodology: Plasma Tpo levels were measured by enzyme-linked immunosorbent assay was measured 3 times i.e. Pre-platelet transfusion of platelets,24h and 48h post-transfusion in 100 severe (GSC≤8)TBI patients. Platelet transfusion response was evaluated and defined as a ≥20% increase in platelet count from baseline and patients were categorized as responders and non-responders to platelet transfusion.
Results: Platelet count was low at admission (89.4±31.1*103 per cumm). Less than 2 units of random donor platelets(RDP) was given to 14% patients,67% patients required2-4 units of RDP and 19% required >4 units of RDP. TPO levels decreased 24h post transfusion compared to pre transfusion (Mean±SD)(127.8±90.2 vs. 142.2±82.6 pg/ml; P 0.07), but elevated at 48h (209.1±74.8 pg/ml; p Pre vs. 48h 0.05). On Average the platelet count improved after transfusion at 24h to 112.7±74.6pg/ml (p Pre vs. 24h 0.003) and continued to rise at 48 h (123.7±82.1 pg/ml; p Pre vs. 48h 0.02). Platelet count and TPO levels were found to be independent (rho -0.12, p 0.38). 62% showed a ≥20% increase in platelet count from baseline (Responders), 38% were non-responders. As significant increase in 24 h post transfusion Tpo levels were seen in responders [median (IQR)] [173.6(0-202.4) pg/ml vs. 164.3(137.1-203.7) pg/ml; p 0.04] compared to pre transfusion levels. Tpo levels in Non-responders did not vary post platelet transfusion [156(0-198.11) pg/ml vs. 158.88(0-198.11) pg/ml; p 0.97]. 28% of Non-responders had low (<81.25 pg/ml) and 2.8% had high (>237.7 pg/ml) pre transfusion Tpo levels. At 24 h post transfusion 26.6% had low and zero had High Tpo levels.
Conclusion: In the present study platelet transfusion response inversely correlates with Tpo levels, as 24h post platelet transfusion Tpo levels were transiently low but insignificant and elevated at 48h post transfusion. In non-responders, the post transfusion TPO levels were not sufficient to mitigate the low platelet counts. Hence, the possibility of transient bone marrow depression in severe TBI patients is suggested, which requires further analysis in a larger study cohort.

Disclosures
No relevant conflicts of interest to declare.
In vitro phenotypic correction of hematopoietic progenitors from Fanconi anemia group A knockout mice
Authors: Rı́o Paula , Segovia José Carlos , Hanenberg Helmut , Casado JoséAntonio , Martı́nez Jesús , Göttsche Kerstin , Cheng Ngan Ching , Van de Vrugt Henri J. , Arwert Fré , Joenje Hans , Bueren Juan A. 
Published: October 2019

AbstractFanconi anemia (FA) is a rare autosomal recessive disease, characterized by bone marrow failure and cancer predisposition. So far, 8 complementation groups have been identified, although mutations in FANCA account for the disease in the majority of FA patients. In this study we characterized the hematopoietic phenotype of a Fanca knockout mouse model and corrected the main phenotypic characteristics of the bone marrow (BM) progenitors using retroviral vectors. The hematopoiesis of these animals was characterized by a modest though significant thrombocytopenia, consistent with reduced numbers of BM megakaryocyte progenitors. As observed in other FA models, the hematopoietic progenitors from Fanca−/− mice were highly sensitive to mitomycin C (MMC). In addition, we observed for the first time in a FA mouse model a marked in vitro growth defect ofFanca−/−progenitors, either when total BM or when purified Lin−Sca-1+ cells were subjected to in vitro stimulation. Liquid cultures ofFanca−/−BM that were stimulated with stem cell factor plus interleukin-11 produced low numbers of granulocyte macrophage colony-forming units, contained a high proportion of apoptotic cells, and generated a decreased proportion of granulocyte versus macrophage cells, compared to normal BM cultures. Aiming to correct the phenotype of Fanca−/−progenitors, purified Lin−Sca-1+ cells were transduced with retroviral vectors encoding the enhanced green fluorescent protein (EGFP) gene and human FANCAgenes. Lin−Sca-1+ cells fromFanca−/−mice were transduced with an efficiency similar to that of samples from wild-type mice. More significantly, transductions with FANCA vectors corrected both the MMC hypersensitivity as well as the impaired ex vivo expansion ability that characterized the BM progenitors ofFanca−/−mice.
The cytoplasmic domain of Mpl receptor transduces exclusive signals in embryonic and fetal hematopoietic cells
Authors: Challier Cécile , Cocault Laurence , Berthier Rolande , Binart Nadine , Dusanter-Fourt Isabelle , Uzan Georges , Souyri Michèle 
Published: October 2019

AbstractThe Mpl receptor plays an important role at the level of adult hematopoietic stem cells, but little is known of its function in embryonic and fetal hematopoiesis. We investigated the signals sent by the MPL cytoplasmic domain in fetal liver hematopoietic progenitors and during embryonic stem (ES) cell hematopoietic commitment. Mpl was found to be expressed only from day 6 of ES cell differentiation into embryoid bodies. Therefore, we expressed Mpl in undifferentiated ES cells or in fetal progenitors and studied the effects on hematopoietic differentiation. To avoid the inadvertent effect of thrombopoietin, we used a chimeric receptor, PM-R, composed of the extracellular domain of the prolactin receptor (PRL-R) and the transmembrane and cytoplasmic domains of Mpl. This allowed activation of the receptor with a hormone that is not involved in hematopoietic differentiation and assessment of the specificity of responses to Mpl by comparing PM-R with another PRL-R chimeric receptor that includes the cytoplasmic domain of the erythropoietin receptor (EPO-R) ([PE-R]). We have shown that the cytoplasmic domain of the Mpl receptor transduces exclusive signals in fetal liver hematopoietic progenitors as compared with that of EPO-R and that it promotes hematopoietic commitment of ES cells. Our findings demonstrate for the first time the specific role of Mpl in early embryonic or fetal hematopoietic progenitors and stem cells.
Rituximab treatment results in impaired secondary humoral immune responsiveness
Authors: van der Kolk Lizet E. , Baars Joke W. , Prins Martin H. , van Oers Marinus H. J. 
Published: October 2019

Abstract
In lymphoma patients, treatment with chimeric CD20 monoclonal antibodies (rituximab) results in a depletion of normal and malignant B cells, persisting for 6 to 9 months. This B-cell depletion leads neither to a decrease in immunoglobulin levels nor an increase in the number of infectious complications. However, the effect of rituximab treatment on the immune responsiveness is unknown. In 11 patients with relapsed, low-grade lymphoma, we investigated the effect of rituximab treatment on the humoral immune response to 2 primary antigens and 2 recall antigens. After rituximab treatment, the humoral immune response to the recall antigens was significantly decreased when compared with the response before treatment. Already before rituximab treatment, none of these patients was able to mount a response to the primary antigens. These findings are relevant regarding the feasibility of rituximab in maintenance treatment and may also offer a rationale for the treatment of antibody-mediated autoimmune diseases with rituximab.