134 research outputs found

    RasGAP Shields Akt from Deactivating Phosphatases in Fibroblast Growth Factor Signaling but Loses This Ability Once Cleaved by Caspase-3.

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    Fibroblast growth factor receptors (FGFRs) are involved in proliferative and differentiation physiological responses. Deregulation of FGFR-mediated signaling involving the Ras/PI3K/Akt and the Ras/Raf/ERK MAPK pathways is causally involved in the development of several cancers. The caspase-3/p120 RasGAP module is a stress sensor switch. Under mild stress conditions, RasGAP is cleaved by caspase-3 at position 455. The resulting N-terminal fragment, called fragment N, stimulates anti-death signaling. When caspase-3 activity further increases, fragment N is cleaved at position 157. This generates a fragment, called N2, that no longer protects cells. Here, we investigated in Xenopus oocytes the impact of RasGAP and its fragments on FGF1-mediated signaling during G2/M cell cycle transition. RasGAP used its N-terminal Src homology 2 domain to bind FGFR once stimulated by FGF1, and this was necessary for the recruitment of Akt to the FGFR complex. Fragment N, which did not associate with the FGFR complex, favored FGF1-induced ERK stimulation, leading to accelerated G2/M transition. In contrast, fragment N2 bound the FGFR, and this inhibited mTORC2-dependent Akt Ser-473 phosphorylation and ERK2 phosphorylation but not phosphorylation of Akt on Thr-308. This also blocked cell cycle progression. Inhibition of Akt Ser-473 phosphorylation and entry into G2/M was relieved by PHLPP phosphatase inhibition. Hence, full-length RasGAP favors Akt activity by shielding it from deactivating phosphatases. This shielding was abrogated by fragment N2. These results highlight the role played by RasGAP in FGFR signaling and how graded stress intensities, by generating different RasGAP fragments, can positively or negatively impact this signaling

    Hydroxychloroquine efficacy and safety in preventing SARS-CoV-2 infection and COVID-19 disease severity during pregnancy (COVID-Preg) : A structured summary of a study protocol for a randomised placebo controlled trial

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    Objectives: The primary objectives of the study are: 1. To assess the effect of hydroxychloroquine (HCQ) in reducing SARS-CoV-2 viral shedding by PCR in infected pregnant women with mild symptoms. 2. To assess the efficacy of HCQ to prevent SARS-CoV-2 infection in pregnant women in contact with an infected or suspected case. 3. To evaluate the effect of HCQ in preventing the development of the COVID-19 disease in asymptomatic SARS-CoV-2-infected pregnant women. The secondary objectives are: 1. To determine the effect of HCQ on the clinical course and duration of the COVID-19 disease in SARS-CoV-2-infected pregnant women. 2. To determine the impact of HCQ on the risk of hospitalization and mortality of SARS-CoV-2-infected pregnant women. 3. To assess the safety and tolerability of HCQ in pregnant women. 4. To describe the clinical presentation of SARS-CoV-2 infection during pregnancy. 5. To describe the effects of maternal SARS-CoV-2 infection on pregnancy and perinatal outcomes by treatment group. 6. To determine the risk of vertical transmission (intra-utero and intra-partum) of SARS-CoV-2. Trial design: Randomized double-blind placebo-controlled two-arm multicentre clinical trial to evaluate the safety and efficacy of HCQ to prevent and/or minimize SARS-CoV-2 infection during pregnancy. Participants will be randomized to receive a 14-day oral treatment course of HCQ or placebo, ratio 1:1. Participants: Study population: pregnant women undergoing routine prenatal follow up or attending emergency units at the participating hospitals who report either symptoms/signs suggestive of COVID-19 disease or close contact with a suspected or confirmed COVID-19 case. Inclusion criteria Women will be invited to participate in the trial and sign an informed consent if they meet the following inclusion criteria. •Presenting with fever (≥37.5°C) and/or one mild symptom suggestive of COVID-19 disease (cough, dyspnoea, chills, odynophagia, diarrhoea, muscle pain, anosmia, dysgeusia, headache) OR being contact*of a SARS-CoV-2 confirmed or suspected case in the past 14 days •More than 12 weeks of gestation (dated by ultrasonography) •Agreement to deliver in the study hospitals Exclusion criteria •Known hypersensitivity to HCQ or other 4-amonoquinoline compounds •History of retinopathy of any aetiology •Concomitant use of digoxin, cyclosporine, cimetidine •Known liver disease •Clinical history of cardiac pathology including known long QT syndrome •Unable to cooperate with the requirements of the study •Participating in other intervention studies •Delivery onset (characterized by painful uterine contractions and variable changes of the cervix, including some degree of effacement and slower progression of dilatation up to 5 cm for first and subsequent labours) The study participants will be stratified by clinical presentation and SARS-CoV-2 PCR results. Assignment of participants to study groups will be as follows: •SARS-CoV-2-PCR confirmed, infected pregnant women: a. symptomatic (n=100) b. asymptomatic (n=100) •SARS-CoV-2 PCR negative pregnant women in contact*with a SARS-CoV-2-infected confirmed or suspected case (n=514).*The ECDC definition of close contact will be followed. The trial will be conducted in five hospitals in Spain: Hospital Clínic of Barcelona, Hospital Sant Joan de Déu and Hospital de la Santa Creu i Sant Pau, in Barcelona, and HM Puerta del Sur and Hospital Universitario de Torrejón, in Madrid. Intervention and comparator: Participants will be randomized to HCQ (400 mg/day for three days, followed by 200 mg/day for 11 days) or placebo (2 tablets for three days, followed by one tablet for 11 days). Main outcomes: The primary outcome is the number of PCR-confirmed infected pregnant women assessed from collected nasopharyngeal and oropharyngeal swabs at day 21 after treatment start (one week after treatment is completed). Randomisation: Allocation of participants to study arms will be done centrally by the trial's Sponsor (the Barcelona Institute for Global Health, ISGlobal) by block randomization. This method will ensure balanced allocation to both arms. The electronic CRF will automatically assign a study number to each participant, depending on her study group and recruitment site. Each number will be related to a treatment number, which assigns them to one of the study arms. Blinding (masking): Participants, caregivers, investigators and those assessing the outcomes will be blinded to group assignment. Study tablets (HCQ and placebo) will be identically packaged in small opaque bottles. Numbers to be randomised (sample size): This study requires 200 SARS-CoV-2 infected and 514 contact pregnant women, randomised 1:1 with 100 and 227 respectively in each study arm. Trial Status: Protocol version 1.0, from May 8th, 2020. Recruitment is ongoing (first patient recruited the 19th May 2020 and recruitment end anticipated by December 2020). Trial registration: EudraCT number: 2020-001587-29, registered 2 April 2020. Clinicaltrials.gov identifier: NCT04410562, retrospectively registered 1 June 2020. Full protocol: The full protocol is attached as an additional file, accessible from the Trials website (Additional file 1). In the interest in expediting dissemination of this material, the familiar formatting has been eliminated; this Letter serves as a summary of the key elements of the full protocol

    Characterization of the Prokaryotic Sodium Channel NavSp Pore with a Microfluidic Bilayer Platform

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    This paper describes the use of a newly-developed micro-chip bilayer platform to examine the electrophysiological properties of the prokaryotic voltage-gated sodium channel pore (NavSp) from Silicibacter pomeroyi. The platform allows up to 6 bilayers to be analysed simultaneously. Proteoliposomes were incorporated into suspended lipid bilayers formed within the microfluidic bilayer chips. The chips provide access to bilayers from either side, enabling the fast and controlled titration of compounds. Dose-dependent modulation of the opening probability by the channel blocking drug nifedipine was measured and its IC50 determined

    Big data analytics — A review of data-mining models for small and medium enterprises in the transportation sector.

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    The need for small and medium enterprises (SMEs) to adopt data analytics has reached a critical point, given the surge of data implied by the advancement of technology. Despite data mining (DM) being widely used in the transportation sector, it is staggering to note that there are minimal research case studies being done on the application of DM by SMEs, specifically in the transportation sector. From the extensive review conducted, the three most common DM models used by large enterprises in the transportation sector are identified, namely “Knowledge Discovery in Database,” “Sample, Explore, Modify, Model and Assess” (SEMMA), and “CRoss Industry Standard Process for Data Mining” (CRISP-DM). The same finding was revealed in the SMEs’ context across the various industries. It was also uncovered that among the three models, CRISP-DM had been widely applied commercially. However, despite CRISP-DM being the de facto DM model in practice, a study carried out to assess the strengths and weakness of the models reveals that they have several limitations with respect to SMEs. This paper concludes that there is a critical need for a novel model to be developed in order to cater to the SMEs’ prerequisite, especially so in the transportation sector context

    Identification of a Sudden Cardiac Death Susceptibility Locus at 2q24.2 through Genome-Wide Association in European Ancestry Individuals

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    Sudden cardiac death (SCD) continues to be one of the leading causes of mortality worldwide, with an annual incidence estimated at 250,000–300,000 in the United States and with the vast majority occurring in the setting of coronary disease. We performed a genome-wide association meta-analysis in 1,283 SCD cases and >20,000 control individuals of European ancestry from 5 studies, with follow-up genotyping in up to 3,119 SCD cases and 11,146 controls from 11 European ancestry studies, and identify the BAZ2B locus as associated with SCD (P = 1.8×10−10). The risk allele, while ancestral, has a frequency of ∼1.4%, suggesting strong negative selection and increases risk for SCD by 1.92–fold per allele (95% CI 1.57–2.34). We also tested the role of 49 SNPs previously implicated in modulating electrocardiographic traits (QRS, QT, and RR intervals). Consistent with epidemiological studies showing increased risk of SCD with prolonged QRS/QT intervals, the interval-prolonging alleles are in aggregate associated with increased risk for SCD (P = 0.006)

    Stem Cell in the Rough

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