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Found 35555 matches. Displaying 31-40
Morse KW, Heinz NK, Abolade JM, Wright-Chisem JI, Russell LA, Zhang M, Mirza SZ, Orange DE, Figgie MP, Sculco PK, Goodman SM
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Tranexamic Acid Does Not Reduce the Risk of Transfusion in Rheumatoid Arthritis Patients Undergoing Total Joint Arthroplasty

JOURNAL OF ARTHROPLASTY 2020 SEP; 35(9):2367-2374
Background: Patients with rheumatoid arthritis (RA) receive transfusions more often than patients with osteoarthritis following lower extremity total joint arthroplasty (TJA), but mitigating factors are not described. Tranexamic acid (TXA) is widely used to reduce blood loss in patients undergoing TJA, but its effect on transfusion rates in patients with RA has not been studied. Methods: We retrospectively reviewed data from a prospectively collected cohort of patients with RA undergoing TJA. Disease activity measured by Clinical Disease Activity Index, patient-reported outcome measures, and serologies was obtained. Baseline characteristics were summarized and compared. Transfusion requirements and TXA usage were obtained from chart review. Logistic regression was used to determine factors associated with transfusion in RA patients undergoing TJA. Results: The cohort included 252 patients, mostly women with longstanding RA and end-stage arthritis requiring TJA. In multivariate analysis, 1 g/dL decrease in baseline hemoglobin (odds ratio [OR] = 0.394, 95% confidence interval [CI] [0.232, 0.669], P = .001), 1-minute increase in surgical duration (OR = 1.022, 95% CI [1.008,1.037], P = .003), and 1-point increase in Clinical Disease Activity Index (OR = 1.079, 95% CI [1.001, 1.162]) were associated with increased risk of transfusion. TXA use was not associated with decreased risk of postoperative transfusion. Conclusions: Preoperative health optimization should include assessment and treatment of anemia in RA patients before TJA, as preoperative hemoglobin level is the main risk factor for postoperative transfusion. Increased disease activity and increased surgical time were independent risk factors for postoperative transfusion but are less modifiable. While TXA did not decrease transfusion risk in this population, a prospective trial is needed to confirm this. (C) 2020 Elsevier Inc. All rights reserved.
Clinical and animal studies show maternal alcohol consumption during pregnancy causes in offspring persistent alterations in neuroimmune and neurochemical systems known to increase alcohol drinking and related behaviors. Studies in lateral hypothalamus (LH) demonstrate in adolescent offspring that maternal oral administration of ethanol stimulates the neuropeptide, melanin-concentrating hormone (MCH), together with the inflammatory chemokine C-C motif ligand 2 (CCL2) and its receptor CCR2 which are increased in most MCH neurons. These effects, consistently stronger in females than males, are detected in embryos, not only in LH but hypothalamic neuroepithelium (NEP) along the third ventricle where neurons are born and CCL2 is stimulated within radial glia progenitor cells and their laterally projecting processes that facilitate MCH neuronal migration toward LH. With ethanol's effects similarly produced by maternal peripheral CCL2 administration and blocked by CCR2 antagonist, we tested here using in utero intracerebroventricular (ICV) injections whether CCL2 acts locally within the embryonic NEP. After ICV injection of CCL2 (0.1 mg/ml) on embryonic day 14 (E14) when neurogenesis peaks, we observed in embryos just before birth (E19) a significant increase in endogenous CCL2 within radial glia cells and their processes in NEP. These auto-regulatory effects, evident only in female embryos, were accompanied by increased density of CCL2 and MCH neurons in LH, more strongly in females than males. These results support involvement of embryonic CCL2/CCR2 neuroimmune system in radial glia progenitor cells in mediating sexually dimorphic effects of maternal challenges such as ethanol on LH MCH neurons that colocalize CCL2 and CCR2. Published by Elsevier Ltd on behalf of IBRO.
Monteiro T, Wysocka M, Tellez E, Monteiro O, Spencer L, Veiga E, Monteiro S, de Pina C, Goncalves D, de Pina S, Ludgero-Correia A, Moreno J, Conceicao T, Aires-de-Sousa M, de Lencastre H, Gray LJ, Pareek M, Jenkins DR, Beleza S, Oggioni MR, Araujo II
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A five-year retrospective study shows increasing rates of antimicrobial drug resistance in Cabo Verde for both Staphylococcus aureus and Escherichia coli

Objectives: Data on baseline drug resistance important in informing future antimicrobial stewardship programs. So far, no data on the antimicrobial drug resistance of clinical isolates available for the African archipelago of Cabo Verde. Methods: We performed a retrospective analysis over years (2013-17) of the drug susceptibility profiles of clinical isolates in the two main hospitals of Cabo Verde. For Escherichia coli and Staphylococcus aureus, representing 47% and 26% of all clinical isolates, the antimicrobial drug resistance profile was reported for six representative drugs. Results: For E. coli we detected an increase in resistance to ampicillin, amoxicillin/clavulanic acid, ceftriaxone, ciprofloxacin and trimethoprim-and for S. aureus to methicillin, erythromycin and trimethoprim-sulfamethoxazole. This increase in both the most commonly isolated bacterial pathogens is alarm as it might compromise empirical treatment in a setting with limited access to laboratory testing. Conclusions: When compared to the published low resistance rates in carriage isolates, the more alarming situation in clinical isolates for S. aureus might encourage antimicrobial stewardship programs to reduce in hospital settings, possibly as part of the Cabo Verdean national plan against antimicrobial drug resistance. (C) 2020 The Author(s). Published by Elsevier Ltd on behalf of International Society for Antimicrobial Chemotherapy.
Machado ACD, Cooper BH, Lei X, Di Felice R, Chen L, Rohs R
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Landscape of DNA binding signatures of myocyte enhancer factor-2B reveals a unique interplay of base and shape readout

NUCLEIC ACIDS RESEARCH 2020 SEP 4; 48(15):8529-8544
Myocyte enhancer factor-2B (MEF2B) has the unique capability of binding to its DNA target sites with a degenerate motif, while still functioning as a gene-specific transcriptional regulator. Identifying its DNA targets is crucial given regulatory roles exerted by members of the MEF2 family and MEF2B's involvement in B-cell lymphoma. Analyzing structural data and SELEX-seq experimental results, we deduced the DNA sequence and shape determinants of MEF2B target sites on a high-throughput basis in vitro for wild-type and mutant proteins. Quantitative modeling of MEF2B binding affinities and computational simulations exposed the DNA readout mechanisms of MEF2B. The resulting binding signature of MEF2B revealed distinct intricacies of DNA recognition compared to other transcription factors. MEF2B uses base readout at its half-sites combined with shape readout at the center of its degenerate motif, where A-tract polarity dictates nuances of binding. The predominant role of shape readout at the center of the core motif, with most contacts formed in the minor groove, differs from previously observed protein-DNA readout modes. MEF2B, therefore, represents a unique protein for studies of the role of DNA shape in achieving binding specificity. MEF2B-DNA recognition mechanisms are likely representative for other members of the MEF2 family.
Su LL, Wang ZH, Xie ST, Hu DH, Cheng YC, Mruk DD, Guan YJ
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Testin regulates the blood-testis barrier via disturbing occludin/ZO-1 association and actin organization

The blood-testis barrier (BTB) separates the seminiferous epithelium into the apical and basal compartments. The BTB has to operate timely and accurately to ensure the correct migration of germ cells, meanwhile maintaining the immunological barrier. Testin was first characterized from primary Sertoli cells, it is a secretory protein and a sensitive biomarker to monitor junctions between Sertoli and germ cells. Till now, the functions of testin on BTB dynamics and the involving mechanisms are unknown. Herein, testin acts as a regulatory protein on BTB integrity. In vitro testin knockdown by RNAi caused significant damage to the Sertoli cell barrier with no apparent changes in the protein levels of several major tight junction (TJ), adhesion junction, and gap junction proteins. Also, testin RNAi caused the diffusion of two TJ structural proteins, occludin and ZO-1, diffusing away from the Sertoli cell surface into the cytoplasm. Association and colocalization between ZO-1 and occludin were decreased after testin RNAi, examined by Co-IP and coimmunofluorescent staining, respectively. Furthermore, testin RNAi induced a dramatic disruption on the arrangement of actin filament bundles and a reduced F-actin/G-actin ratio. The actin regulatory protein ARP3 appeared at the Sertoli cell interface after testin RNAi without its protein level change, whereas overexpressing testin in Sertoli cells showed no effect on TJ barrier integrity. The above findings suggest that besides as a monitor for Sertoli-germ cell junction integrity, testin is also an essential molecule to maintain Sertoli-Sertoli junctions.
Fiore VF, Krajnc M, Quiroz FG, Levorse J, Pasolli HA, Shvartsman SY, Fuchs E
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Mechanics of a multilayer epithelium instruct tumour architecture and function

NATURE 2020 SEP 17; 585(7825):433–439
Mathematical and experimental approaches are used to investigate the mechanical forces that shape the tumour architecture of two different common forms of skin cancer: basal cell carcinomas and invasive squamous cell carcinomas. Loss of normal tissue architecture is a hallmark of oncogenic transformation(1). In developing organisms, tissues architectures are sculpted by mechanical forces during morphogenesis(2). However, the origins and consequences of tissue architecture during tumorigenesis remain elusive. In skin, premalignant basal cell carcinomas form 'buds', while invasive squamous cell carcinomas initiate as 'folds'. Here, using computational modelling, genetic manipulations and biophysical measurements, we identify the biophysical underpinnings and biological consequences of these tumour architectures. Cell proliferation and actomyosin contractility dominate tissue architectures in monolayer, but not multilayer, epithelia. In stratified epidermis, meanwhile, softening and enhanced remodelling of the basement membrane promote tumour budding, while stiffening of the basement membrane promotes folding. Additional key forces stem from the stratification and differentiation of progenitor cells. Tumour-specific suprabasal stiffness gradients are generated as oncogenic lesions progress towards malignancy, which we computationally predict will alter extensile tensions on the tumour basement membrane. The pathophysiologic ramifications of this prediction are profound. Genetically decreasing the stiffness of basement membranes increases membrane tensions in silico and potentiates the progression of invasive squamous cell carcinomas in vivo. Our findings suggest that mechanical forces-exerted from above and below progenitors of multilayered epithelia-function to shape premalignant tumour architectures and influence tumour progression.
Gruber CN, Calis JJA, Buta S, Evrony G, Martin JC, Uhl SA, Caron R, Jarchin L, Dunkin D, Phelps R, Webb BD, Saland JM, Merad M, Orange JS, Mace EM, Rosenberg BR, Gelb BD, Bogunovic D
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Complex Autoinflammatory Syndrome Unveils Fundamental Principles of JAK1 Kinase Transcriptional and Biochemical Function

IMMUNITY 2020 SEP 15; 53(3): 672-684.e11
Autoinflammatory disease can result from monogenic errors of immunity. We describe a patient with early-onset multi-organ immune dysregulation resulting from a mosaic, gain-of-function mutation (S7031) in JAK1, encoding a kinase essential for signaling downstream of >25 cytokines. By custom single-cell RNA sequencing, we examine mosaicism with single-cell resolution. We find that JAK1 transcription was predominantly restricted to a single allele across different cells, introducing the concept of a mutational "transcriptotype" that differs from the genotype. Functionally, the mutation increases JAK1 activity and transactivates partnering JAKs, independent of its catalytic domain. S7031 JAK1 is not only hypermorphic for cytokine signaling but also neomorphic, as it enables signaling cascades not canonically mediated by JAK1 Given these results, the patient was treated with tofacitinib, a JAK inhibitor, leading to the rapid resolution of clinical disease. These findings offer a platform for personalized medicine with the concurrent discovery of fundamental biological principles.
Requena D, Medico A, Chacon RD, Ramirez M, Marin-Sanchez O
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Identification of Novel Candidate Epitopes on SARS-CoV-2 Proteins for South America: A Review of HLA Frequencies by Country

FRONTIERS IN IMMUNOLOGY 2020 SEP 3; 11(?):? Article 2008
Coronavirus disease (COVID-19), caused by the virus SARS-CoV-2, is already responsible for more than 4.3 million confirmed cases and 295,000 deaths worldwide as of May 15, 2020. Ongoing efforts to control the pandemic include the development of peptide-based vaccines and diagnostic tests. In these approaches, HLA allelic diversity plays a crucial role. Despite its importance, current knowledge of HLA allele frequencies in South America is very limited. In this study, we have performed a literature review of datasets reporting HLA frequencies of South American populations, available in scientific literature and/or in the Allele Frequency Net Database. This allowed us to enrich the current scenario with more than 12.8 million data points. As a result, we are presenting updated HLA allelic frequencies based on country, including 91 alleles that were previously thought to have frequencies either under 5% or of an unknown value. Using alleles with an updated frequency of at least >= 5% in any South American country, we predicted epitopes in SARS-CoV-2 proteins using NetMHCpan (I and II) and MHC flurry. Then, the best predicted epitopes (class-I and -II) were selected based on their binding to South American alleles (Coverage Score). Class II predicted epitopes were also filtered based on their three-dimensional exposure. We obtained 14 class-I and four class-II candidate epitopes with experimental evidence (reported in the Immune Epitope Database and Analysis Resource), having good coverage scores for South America. Additionally, we are presenting 13 HLA-I and 30 HLA-II novel candidate epitopes without experimental evidence, including 16 class-II candidates in highly exposed conserved areas of the NTD and RBD regions of the Spike protein. These novel candidates have even better coverage scores for South America than those with experimental evidence. Finally, we show that recent similar studies presenting candidate epitopes also predicted some of our candidates but discarded them in the selection process, resulting in candidates with suboptimal coverage for South America. In conclusion, the candidate epitopes presented provide valuable information for the development of epitope-based strategies against SARS-CoV-2, such as peptide vaccines and diagnostic tests. Additionally, the updated HLA allelic frequencies provide a better representation of South America and may impact different immunogenetic studies.
Edri Y, Meron E, Yochelis A
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Spatial asymmetries of resonant oscillations in periodically forced heterogeneous media

PHYSICA D-NONLINEAR PHENOMENA 2020 SEP; 410(?):? Article 132501
Spatially localized oscillations in periodically forced systems are intriguing phenomena. They may occur in spatially homogeneous media (oscillons), but quite often emerge in heterogeneous media, such as the auditory system, where localized oscillations are believed to play an important role in frequency discrimination of incoming sound waves. In this paper, we use an amplitude-equation approach to study the spatial profile of the oscillations and the factors that affect it. More specifically, we use a variant of the forced complex Ginzburg-Landau (FCGL) equation to describe an oscillatory system below the Hopf bifurcation with space-dependent Hopf frequency, subject to both parametric and additive forcing. We show that spatial heterogeneity, combined with bistability of system states, results in spatial asymmetry of the localized oscillations. We further identify parameters that control that asymmetry, and characterize the spatial profile of the oscillations in terms of maximum amplitude, location, width and asymmetry. Our results bear qualitative similarities to empirical observation trends that have found in the auditory system. (C) 2020 Elsevier B.V. All rights reserved.
Zou CH, Vercauteren KOA, Michailidis E, Kabbani M, Zoluthkin I, Quirk C, Chiriboga L, Yazicioglu M, Anguela XM, Meuleman P, High KA, Herzog RW, de Jong YP
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Experimental Variables that Affect Human Hepatocyte MV Transduction in Liver Chimeric Mice

Adeno-associated virus (AAV) vector serotypes vary in their ability to transduce hepatocytes from different species. Chimeric mouse models harboring human hepatocytes have shown translational promise for liver-directed gene therapies. However, many variables that influence human hepatocyte transduction and transgene expression in such models remain poorly defined. Here, we aimed to test whether three experimental conditions influence AAV transgene expression in immunodeficient, fumaryl-acetoactetate-hydrolase-deficient (Fah(-/-)) chimeric mice repopulated with primary human hepatocytes. We examined the effects of the murine liver injury cycle, human donor variability, and vector doses on hepatocyte transduction with various AAV serotypes expressing a green fluorescent protein (GFP). We determined that the timing of AAV vector challenge in the liver injury cycle resulted in up to 7-fold differences in the percentage of GFP expressing human hepatocytes. The GFP+ hepatocyte frequency varied 7-fold between human donors without, however, changing the relative transduction efficiency between serotypes for an individual donor. There was also a clear relationship between AAV vector doses and human hepatocyte transduction and transgene expression. We conclude that several experimental variables substantially affect human hepatocyte transduction in the Fah(-/-) chimera model, attention to which may improve reproducibility between findings from different laboratories.