2,326 research outputs found

    The Role of Oxidative Stress in the Development of Diabetic Cardiomyopathy

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    Diabetes mellitus (DM) is a major global health problem, currently affecting about 460 million people while another billion have prediabetes, all costing the governments of the world over $1 trillion USAD to diagnose and treat diabetic patients, so that they can enjoy a better quality of life. DM induces hyperglycemia (HG), which in turn plays a significant role in the development of diabetic cardiomyopathy (DCM), which is responsible for over 80% of diabetic mortality. The exact mechanisms underlying DCM remain incompletely clear, although several pathological mechanisms responsible for DCM have been proposed in the literature. One such mechanism is oxidative stress (OS), which is widely considered as one of the major causes for the pathogenesis of the disease. There is a growing scientific and public interest in connecting oxidative stress with a variety of pathological conditions, including DM as well as other human diseases. HG-induced oxidative stress is a major risk factor for the development of micro-vascular pathogenesis in the diabetic myocardium, resulting in myocardial cell death, hypertrophy, fibrosis, abnormalities of calcium homeostasis and endothelial dysfunction. The aim of this review is to highlight the role of oxidative stress in the development of DCM

    Hyperglycemia-induced cardiac contractile dysfunction in the diabetic heart

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    The development of a diabetic cardiomyopathy is a multifactorial process, and evidence is accumulating that defects in intracellular free calcium concentration [Ca2+]i or its homeostasis are related to impaired mechanical performance of the diabetic heart leading to a reduction in contractile dysfunction. Defects in ryanodine receptor, reduced activity of the sarcoplasmic reticulum calcium pump (SERCA) and, along with reduced activity of the sodium-calcium exchanger (NCX) and alterations in myofilament, collectively cause a calcium imbalance within the diabetic cardiomyocytes. This in turn is characterized by cytosolic calcium overloading or elevated diastolic calcium leading to heart failure. Numerous studies have been performed to identify the cellular, subcellular, and molecular derangements in diabetes-induced cardiomyopathy (DCM), but the precise mechanism(s) is still unknown. This review focuses on the mechanism behind DCM, the onset of contractile dysfunction, and the associated changes with special emphasis on hyperglycemia, mitochondrial dysfunction in the diabetic heart. Further, management strategies, including treatment and emerging therapeutic modalities, are discussed

    Two-dimensional (2D) d-Silicates from abundant natural minerals

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    In the last decade, the materials community has been exploring new 2D materials (graphene, metallene, TMDs, TMCs, MXene, among others) that have unique physical and chemical properties. Recently, a new family of 2D materials, the so-called 2D silicates, have been proposed. They are predicted to exhibit exciting properties (such as high catalytic activity, piezoelectricity, and 2D magnetism). In the current work, we demonstrate a generic approach to the synthesis of large-scale 2D silicates from selected minerals, such as Diopside (d). Different experimental techniques were used to confirm the existence of the 2D structures (named 2D-d-silicates). DFT simulations were also used to gain insight into the structural features and energy harvesting mechanisms (flexoelectric response generating voltage up to 10 V). The current approach is completely general and can be utilized for large-scale synthesis of 2D silicates and their derivatives, whose large-scale syntheses have been elusive

    Paracheck-Pf® accuracy and recently treated Plasmodium falciparum infections: is there a risk of over-diagnosis?

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    BACKGROUND: An assessment of the accuracy of Paracheck Pf, a malaria rapid diagnostic test (RDT) detecting histidine rich protein 2 was undertaken amongst children aged 6-59 months in eastern Democratic Republic of Congo. METHODS: This RDT assessment occurred in conjunction with an ACT efficacy trial. Febrile children were simultaneously screened with both RDT and high quality microscopy and those meeting inclusion criteria were followed for 35 days. RESULTS: 358 febrile children were screened with 180 children recruited for five weeks follow-up. On screening, the RDT accurately diagnosed all 235 true malaria cases, indicating 100% RDT sensitivity. Of the 123 negative slides, the RDT gave 59 false-positive results, indicating 52.0% (64/123) RDT specificity. During follow-up after treatment with an artemisinin-based combination therapy, 98.2% (110/112), 94.6% (106/112), 92.0% (103/112) and 73.5% (50/68) of effectively treated children were still false-positive by RDT at days 14, 21, 28 and 35, respectively. CONCLUSION: Results show that though the use of Paracheck-Pf is as sensitive as microscopy in detecting true malaria cases, a low specificity did present a high frequency of false-positive RDT results. What's more, a duration of RDT false-positivity was found that significantly surpassed the 'fortnight' after effective treatment reported by its manufacturer. Though further research is needed in assessing RDT accuracy, study results showing the presence of frequent false positivity should be taken into consideration to avoid clinicians inappropriately focusing on malaria, not identifying the true cause of illness, and providing unnecessary treatment

    Correlations between Income inequality and antimicrobial resistance.

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    Objectives: The aim of this study is to investigate if correlations exist between income inequality and antimicrobial resistance. This study's hypothesis is that income inequality at the national level is positively correlated with antimicrobial resistance within developed countries. Data collection and analysis: income inequality data were obtained from the Standardized World Income Inequality Database. Antimicrobial resistance data were obtained from the European antimicrobial Resistance Surveillance Network and outpatient antimicrobial consumption data, measured by Defined daily Doses per 1000 inhabitants per day, from the European Surveillance of antimicrobial Consumption group. Spearman's correlation coefficient (r) defined strengths of correlations of: > 0.8 as strong, > 0.5 as moderate and > 0.2 as weak. Confidence intervals and p values were defined for all r values. Correlations were calculated for the time period 2003-10, for 15 European countries. Results: income inequality and antimicrobial resistance correlations which were moderate or strong, with 95% confidence intervals > 0, included the following. Enterococcus faecalis resistance to aminopenicillins, vancomycin and high level gentamicin was moderately associated with income inequality (r= ≥0.54 for all three antimicrobials). Escherichia coli resistance to aminoglycosides, aminopenicillins, third generation cephalosporins and fluoroquinolones was moderately-strongly associated with income inequality (r= ≥0.7 for all four antimicrobials). Klebsiella pneumoniae resistance to third generation cephalosporins, aminoglycosides and fluoroquinolones was moderately associated with income inequality (r= ≥0.5 for all three antimicrobials). Staphylococcus aureus methicillin resistance and income inequality were strongly associated (r=0.87). Conclusion: as income inequality increases in European countries so do the rates of antimicrobial resistance for bacteria including E. faecalis, E. coli, K. pneumoniae and S. aureus. Further studies are needed to confirm these findings outside Europe and investigate the processes that could causally link income inequality and antimicrobial resistance

    ORAI1 calcium channel orchestrates skin homeostasis

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    To achieve and maintain skin architecture and homeostasis, keratinocytes must intricately balance growth, differentiation, and polarized motility known to be governed by calcium. Orai1 is a pore subunit of a store-operated Ca(2+) channel that is a major molecular counterpart for Ca(2+) influx in nonexcitable cells. To elucidate the physiological significance of Orai1 in skin, we studied its functions in epidermis of mice, with targeted disruption of the orai1 gene, human skin sections, and primary keratinocytes. We demonstrate that Orai1 protein is mainly confined to the basal layer of epidermis where it plays a critical role to control keratinocyte proliferation and polarized motility. Orai1 loss of function alters keratinocyte differentiation both in vitro and in vivo. Exploring underlying mechanisms, we show that the activation of Orai1-mediated calcium entry leads to enhancing focal adhesion turnover via a PKCβ-Calpain-focal adhesion kinase pathway. Our findings provide insight into the functions of the Orai1 channel in the maintenance of skin homeostasis

    Integrated genomics of ovarian xenograft tumor progression and chemotherapy response

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    <p>Abstract</p> <p>Background</p> <p>Ovarian cancer is the most deadly gynecological cancer with a very poor prognosis. Xenograft mouse models have proven to be one very useful tool in testing candidate therapeutic agents and gene function <it>in vivo</it>. In this study we identify genes and gene networks important for the efficacy of a pre-clinical anti-tumor therapeutic, MT19c.</p> <p>Methods</p> <p>In order to understand how ovarian xenograft tumors may be growing and responding to anti-tumor therapeutics, we used genome-wide mRNA expression and DNA copy number measurements to identify key genes and pathways that may be critical for SKOV-3 xenograft tumor progression. We compared SKOV-3 xenografts treated with the ergocalciferol derived, MT19c, to untreated tumors collected at multiple time points. Cell viability assays were used to test the function of the PPARγ agonist, Rosiglitazone, on SKOV-3 cell growth.</p> <p>Results</p> <p>These data indicate that a number of known survival and growth pathways including Notch signaling and general apoptosis factors are differentially expressed in treated vs. untreated xenografts. As tumors grow, cell cycle and DNA replication genes show increased expression, consistent with faster growth. The steroid nuclear receptor, PPARγ, was significantly up-regulated in MT19c treated xenografts. Surprisingly, stimulation of PPARγ with Rosiglitazone reduced the efficacy of MT19c and cisplatin suggesting that PPARγ is regulating a survival pathway in SKOV-3 cells. To identify which genes may be important for tumor growth and treatment response, we observed that MT19c down-regulates some high copy number genes and stimulates expression of some low copy number genes suggesting that these genes are particularly important for SKOV-3 xenograft growth and survival.</p> <p>Conclusions</p> <p>We have characterized the time dependent responses of ovarian xenograft tumors to the vitamin D analog, MT19c. Our results suggest that PPARγ promotes survival for some ovarian tumor cells. We propose that a combination of regulated expression and copy number can identify genes that are likely important for chemotherapy response. Our findings suggest a new approach to identify candidate genes that are critical for anti-tumor therapy.</p

    Pan-Cancer Analysis of lncRNA Regulation Supports Their Targeting of Cancer Genes in Each Tumor Context

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    Long noncoding RNAs (lncRNAs) are commonly dys-regulated in tumors, but only a handful are known toplay pathophysiological roles in cancer. We inferredlncRNAs that dysregulate cancer pathways, onco-genes, and tumor suppressors (cancer genes) bymodeling their effects on the activity of transcriptionfactors, RNA-binding proteins, and microRNAs in5,185 TCGA tumors and 1,019 ENCODE assays.Our predictions included hundreds of candidateonco- and tumor-suppressor lncRNAs (cancerlncRNAs) whose somatic alterations account for thedysregulation of dozens of cancer genes and path-ways in each of 14 tumor contexts. To demonstrateproof of concept, we showed that perturbations tar-geting OIP5-AS1 (an inferred tumor suppressor) andTUG1 and WT1-AS (inferred onco-lncRNAs) dysre-gulated cancer genes and altered proliferation ofbreast and gynecologic cancer cells. Our analysis in-dicates that, although most lncRNAs are dysregu-lated in a tumor-specific manner, some, includingOIP5-AS1, TUG1, NEAT1, MEG3, and TSIX, synergis-tically dysregulate cancer pathways in multiple tumorcontexts

    Genomic, Pathway Network, and Immunologic Features Distinguishing Squamous Carcinomas

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    This integrated, multiplatform PanCancer Atlas study co-mapped and identified distinguishing molecular features of squamous cell carcinomas (SCCs) from five sites associated with smokin

    Spatial Organization and Molecular Correlation of Tumor-Infiltrating Lymphocytes Using Deep Learning on Pathology Images

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    Beyond sample curation and basic pathologic characterization, the digitized H&E-stained images of TCGA samples remain underutilized. To highlight this resource, we present mappings of tumorinfiltrating lymphocytes (TILs) based on H&E images from 13 TCGA tumor types. These TIL maps are derived through computational staining using a convolutional neural network trained to classify patches of images. Affinity propagation revealed local spatial structure in TIL patterns and correlation with overall survival. TIL map structural patterns were grouped using standard histopathological parameters. These patterns are enriched in particular T cell subpopulations derived from molecular measures. TIL densities and spatial structure were differentially enriched among tumor types, immune subtypes, and tumor molecular subtypes, implying that spatial infiltrate state could reflect particular tumor cell aberration states. Obtaining spatial lymphocytic patterns linked to the rich genomic characterization of TCGA samples demonstrates one use for the TCGA image archives with insights into the tumor-immune microenvironment
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