640 research outputs found

    C-MYC Transcriptionally Amplifies SOX2 Target Genes to Regulate Self-Renewal in Multipotent Otic Progenitor Cells

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    Summary Sensorineural hearing loss is caused by the loss of sensory hair cells and neurons of the inner ear. Once lost, these cell types are not replaced. Two genes expressed in the developing inner ear are c-Myc and Sox2. We created immortalized multipotent otic progenitor (iMOP) cells, a fate-restricted cell type, by transient expression of C-MYC in SOX2-expressing otic progenitor cells. This activated the endogenous C-MYC and amplified existing SOX2-dependent transcripts to promote self-renewal. RNA-seq and ChIP-seq analyses revealed that C-MYC and SOX2 occupy over 85% of the same promoters. C-MYC and SOX2 target genes include cyclin-dependent kinases that regulate cell-cycle progression. iMOP cells continually divide but retain the ability to differentiate into functional hair cells and neurons. We propose that SOX2 and C-MYC regulate cell-cycle progression of these cells and that downregulation of C-MYC expression after growth factor withdrawal serves as a molecular switch for differentiation

    Comparison and Analysis of Colorant in Toner Cartridges: A Material Safety Data Sheet Study

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    Nowadays, electronic devices such as mobile phones and tablets are gadgets that have become common in most people’s daily lives. Although people often use tablets to read files, newspapers, or other papers, printing some documents is still necessary and convenient for most people. Therefore, a printer is one of the basic machines that many people use for work or to learn. Toner cartridges are the main components that print high-quality images or text on paper and are therefore of research value. Existing literature lacks research on performance of different printers and toners. Therefore, this study investigated and analyzed different types and brands of toners. In the study, toner cartridges provided by the four major suppliers were compared with data provided in material safety data sheets (MSDS) based primarily on different products. A comprehensive review and analysis of the concentration, function, definition, and impact involved in the product was conducted in this study

    Single-Cell Fluorescence Analysis of Pseudotemporal Ordered Cells Provides Protein Expression Dynamics for Neuronal Differentiation

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    Stem cell replacement therapy is a potential method for repopulating lost spiral ganglion neurons (SGNs) in the inner ear. Efficacy of cell replacement relies on proper differentiation. Defining the dynamic expression of different transcription factors essential for neuronal differentiation allows us to monitor the progress and determine when the protein functions in differentiating stem cell cultures. Using immortalized multipotent otic progenitors (iMOPs) as a cellular system for SGN differentiation, a method for determining dynamic protein expression from heterogeneous cultures was developed. iMOP-derived neurons were identified and ordered by increasing neurite lengths to create a pseudotime course that reflects the differentiation trajectory. The fluorescence intensities of transcription factors SOX2 and NEUROD1 from individual pseudotemporally ordered cells were measured. Individual cells were grouped by K-means clustering and the mean fluorescence intensity for each cluster determined. Curve fit of the mean fluorescence represented the protein expression dynamics in differentiating cells. The method provides information about protein expression dynamics in differentiating stem cell cultures

    A Visual Analytics Framework for Reviewing Streaming Performance Data

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    Understanding and tuning the performance of extreme-scale parallel computing systems demands a streaming approach due to the computational cost of applying offline algorithms to vast amounts of performance log data. Analyzing large streaming data is challenging because the rate of receiving data and limited time to comprehend data make it difficult for the analysts to sufficiently examine the data without missing important changes or patterns. To support streaming data analysis, we introduce a visual analytic framework comprising of three modules: data management, analysis, and interactive visualization. The data management module collects various computing and communication performance metrics from the monitored system using streaming data processing techniques and feeds the data to the other two modules. The analysis module automatically identifies important changes and patterns at the required latency. In particular, we introduce a set of online and progressive analysis methods for not only controlling the computational costs but also helping analysts better follow the critical aspects of the analysis results. Finally, the interactive visualization module provides the analysts with a coherent view of the changes and patterns in the continuously captured performance data. Through a multi-faceted case study on performance analysis of parallel discrete-event simulation, we demonstrate the effectiveness of our framework for identifying bottlenecks and locating outliers.Comment: This is the author's preprint version that will be published in Proceedings of IEEE Pacific Visualization Symposium, 202

    Cardiac Involvement related to COVID-19 Infection and Vaccination in Children and Adolescents – Hong Kong's Perspective

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    Myocarditis and Pericarditis have many virological and immunological causes. This article described the SARS-CoV involvement to the heart in children and adolescents, also the entity Multisystem Inflammatory Syndrome in Children (MIS-C), a rare but severe consequence of SARS-CoV2 infection. Hong Kong case definition of MIS-C was listed. The consensus from overseas experts was that MIS-C should be managed by multidisciplinary team with a structured long-term follow-up to monitor the functioning of various organs and ascertain the prognosis. The side effect mRNA vaccination causing myocarditis and pericarditis is also concern of paediatricians worldwide. Hong Kong published local epidemiology of acute myocarditis and pericarditis among adolescents following Comirnaty vaccination, the local and overseas data were used in fine-tuning the COVID vaccination program in children and adolescents. To prevent severe and fatal outcome of COVID-19 diseases, it is important to educate the public and to promote COVID-19 vaccination in the community, also to continue monitoring the safety of the available vaccines

    U.S. adult perceptions of the harmfulness of tobacco products: descriptive T findings from the 2013–14 baseline wave 1 of the path study

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    Introduction: This study is the first nationally representative survey of U.S. adults (18+) to examine perceptions of the relative harms of eight non-cigarette tobacco products. Methods: Data are from Wave 1 of the Population Assessment of Tobacco and Health (PATH) Study Adult Questionnaire, a nationally representative study of 32,320 adults in the United States conducted from September 2013 to December 2014. Results: 40.7% of adults believed that electronic cigarettes were less harmful than cigarettes, and 17.8% of adults believed that hookah was less harmful than cigarettes. Those less knowledgeable about the health risks of smoking were more likely to believe that the non-cigarette products were less harmful than cigarettes. Current non-cigarette tobacco product users were more likely to perceive that product to be less harmful than cigarettes (except filtered cigars). There was a significant positive correlation between beliefs that cigarettes were harmful and the likelihood of using hookah; perceptions of the harmfulness of cigarettes was not associated with the likelihood of using any other product. Conclusions: Perceptions of harmfulness varied widely across non-cigarette tobacco products. E-cigarettes and hookah in particular are seen as less harmful compared to cigarettes

    Burning Cold: Involvement of TRPA1 in Noxious Cold Sensation

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    Soon after its discovery ten years ago, the ion channel TRPA1 was proposed as a sensor of noxious cold. Evidence for its activation by painfully cold temperatures (below ~15° C) has been mixed, however. Some groups found that cold elicits a nonselective conductance in cells expressing TRPA1; others found no activation, or argued that activation is an indirect effect of elevated Ca2+Ca^{ 2+} . Sensory cells from the trigeminal and dorsal root ganglia that are activated by cold were sometimes correlated with those cells expressing TRPA1; other times not. Mice lacking TRPA1 showed behavioral defi cits for some assays of painful cold sensation, but not others. New evidence tends to support direct activation of TRPA1 by cold, and the slow and relatively weak activation of TRPA1 by cold helps reconcile some confl icting studies

    Broad activation of the Parkin pathway induces synaptic mitochondrial deficits in early tauopathy

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    Mitochondrial defects are a hallmark of early pathophysiology in Alzheimer’s disease, with pathologically phosphorylated tau reported to induce mitochondrial toxicity. Mitophagy constitutes a key pathway in mitochondrial quality control by which damaged mitochondria are targeted for autophagy. However, few details are known regarding the intersection of mitophagy and pathologies in tauopathy. Here, by applying biochemical and cell biological approaches including time-lapse confocal imaging in live tauopathy neurons, combined with gene rescue experiments via stereotactic injections of adeno-associated virus particles into tauopathy mouse brains, electrophysiological recordings and behavioural tests, we demonstrate for the first time that mitochondrial distribution deficits at presynaptic terminals are an early pathological feature in tauopathy brains. Furthermore, Parkin-mediated mitophagy is extensively activated in tauopathy neurons, which accelerates mitochondrial Rho GTPase 1 (Miro1) turnover and consequently halts Miro1-mediated mitochondrial anterograde movement towards synaptic terminals. As a result, mitochondrial supply at tauopathy synapses is disrupted, impairing synaptic function. Strikingly, increasing Miro1 levels restores the synaptic mitochondrial population by enhancing mitochondrial anterograde movement and thus reverses tauopathy-associated synaptic failure. In tauopathy mouse brains, overexpression of Miro1 markedly elevates synaptic distribution of mitochondria and protects against synaptic damage and neurodegeneration, thereby counteracting impairments in learning and memory as well as synaptic plasticity. Taken together, our study reveals that activation of the Parkin pathway triggers an unexpected effect—depletion of mitochondria from synaptic terminals, a characteristic feature of early tauopathy. We further provide new mechanistic insights into how parkin activation-enhanced Miro1 degradation and impaired mitochondrial anterograde transport drive tauopathy-linked synaptic pathogenesis and establish a foundation for future investigations into new therapeutic strategies to prevent synaptic deterioration in Alzheimer’s disease and other tauopathies

    Genome-Wide Association Study of Hepatocellular Carcinoma in Southern Chinese Patients with Chronic Hepatitis B Virus Infection

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    One of the most relevant risk factors for hepatocellular carcinoma (HCC) development is chronic hepatitis B virus (HBV) infection, but only a fraction of chronic HBV carriers develop HCC, indicating that complex interactions among viral, environmental and genetic factors lead to HCC in HBV-infected patients. So far, host genetic factors have incompletely been characterized. Therefore, we performed a genome-wide association (GWA) study in a Southern Chinese cohort consisting of 95 HBV-infected HCC patients (cases) and 97 HBV-infected patients without HCC (controls) using the Illumina Human610-Quad BeadChips. The top single nucleotide polymorphisms (SNPs) were then validated in an independent cohort of 500 cases and 728 controls. 4 SNPs (rs12682266, rs7821974, rs2275959, rs1573266) at chromosome 8p12 showed consistent association in both the GWA and replication phases (ORcombined = 1.31–1.39; pcombined = 2.71×10−5–5.19×10−4; PARcombined = 26–31%). We found a 2.3-kb expressed sequence tag (EST) in the region using in-silico data mining and verified the existence of the full-length EST experimentally. The expression level of the EST was significantly reduced in human HCC tumors in comparison to the corresponding non-tumorous liver tissues (P<0.001). Results from sequence analysis and in-vitro protein translation study suggest that the transcript might function as a long non-coding RNA. In summary, our study suggests that variations at chromosome 8p12 may promote HCC in patients with HBV. Further functional studies of this region may help understand HBV-associated hepatocarcinogenesis

    Temporal trends and patterns of infective endocarditis in a Chinese population:A territory-wide study in Hong Kong (2002-2019)

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    BACKGROUND: The characteristics of infective endocarditis (IE) in Asians are poorly understood. Therefore, we aim to describe the epidemiological trends and clinical features of IE in Hong Kong. METHODS: All patients with incident IE from 2002–2019 in a territory-wide clinical database in Hong Kong were identified. We studied the age- and sex-adjusted and one-year mortality of IE between 2002 and 2019 and identified significant contributors to 1-year all-cause death using the attributable fraction. We used propensity score and inverse propensity of treatment weighting to study the association of surgery with mortality. FINDINGS: A total of 5139 patients (60.4 ± 18.2years, 37% women) were included. The overall incidence of IE was 4.9 per 100,000 person-year, which did not change over time (P = 0.17). Patients in 2019 were older and more comorbid than those in 2002. The one-year crude mortality rate was 30% in 2002, which did not change significantly over time (P = 0.10). Between 2002 and 2019, the rate of surgery increased and was associated with a 51% risk reduction in 1-year all-cause mortality (Hazard Ratio 0.49 [0.28–0.87], P = 0.015). Advanced age (attributable fraction 19%) and comorbidities (attributable fraction 15%) were significant contributors to death. INTERPRETATION: The incidence of IE in Hong Kong did not change between 2002 and 2019. Patients with IE in 2019 were older and had more comorbidities than those in 2002. Mortality of IE remains persistently high in Hong Kong. Together, these data can guide public health strategies to improve the outcomes of patients with IE. FUNDING: This work was supported by Sanming Project of Medicine in Shenzhen, China [No. SZSM201911020] and HKU-SZH Fund for Shenzhen Key Medical Discipline [No. SZXK2020081]
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