1,933 research outputs found

    A scalable insect cell-based production process of the human recombinant BMX for in-vitro covalent ligand high-throughput screening.

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    Bone Marrow Tyrosine kinase in the chromosome X (BMX) is a TEC family kinase associated with numerous pathological pathways in cancer cells. Covalent inhibition of BMX activity holds promise as a therapeutic approach against cancer. To screen for potent and selective covalent BMX inhibitors, large quantities of highly pure BMX are normally required which is challenging with the currently available production and purification processes. Here, we developed a scalable production process for the human recombinant BMX (hrBMX) using the insect cell-baculovirus expression vector system. Comparable expression levels were obtained in small-scale shake flasks (13 mL) and in stirred-tank bioreactors (STB, 5 L). A two-step chromatographic-based process was implemented, reducing purification times by 75% when compared to traditional processes, while maintaining hrBMX stability. The final production yield was 24 mg of purified hrBMX per litter of cell culture, with a purity of > 99%. Product quality was assessed and confirmed through a series of biochemical and biophysical assays, including circular dichroism and dynamic light scattering. Overall, the platform herein developed was capable of generating 100 mg purified hrBMX from 5 L STB in just 34 days, thus having the potential to assist in-vitro covalent ligand high-throughput screening for BMX activity inhibition

    Thrombolysis in Patients Aged over 80 Years Is Equally Effective and Safe

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    BACKGROUND: Despite stroke's high prevalence in the elderly, intravenous thrombolysis is licensed in Europe only for patients younger than 80 years old. We aimed to compare the functional outcomes and complication rates in patients older versus younger than 80 years old treated with intravenous thrombolysis. METHODS: A retrospective observational study of patients who received intravenous thrombolysis in a stroke unit between January 1, 2009, and June 30, 2012, was conducted. Variables were compared between 2 subgroups (≤80 and >80 years). RESULTS: Overall, 512 patients underwent intravenous thrombolysis, of which 13.1% were over 80 years. The mean age was 65.4 years in the younger subgroup and 82.9 years in the older subgroup. Prior independence rates did not differ between the subgroups. Prevalence of atrial fibrillation and cardioembolic stroke was higher in the older subgroup (P = .004 and .026). Only 3% of the elderly with atrial fibrillation were taking oral anticoagulants. Symptoms-to-needle time was lower in the older subgroup (P = .048). Stroke severity was higher in patients over 80 years (P = .026). There was significant improvement in the National Institutes of Health Stroke Scale score 7 days after intravenous thrombolysis (P < .001) in both subgroups. The proportion of patients with 3 months' favorable outcome and independence, hemorrhagic transformation, and mortality rates were similar in both subgroups. CONCLUSIONS: Elderly patients' benefits and outcomes from intravenous thrombolysis treatment were identical to the younger subgroup without excess hemorrhagic transformation or mortality. These results favor the use of intravenous thrombolysis in patients over 80 years.info:eu-repo/semantics/publishedVersio

    The Impact of the COVID-19 Pandemic on Medical Education: a Systematic Review of Distance Learning, Student’s Perceptions, and Mental Health

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    INTRODUCTION: the COVID-19 pandemic has impacted on mortality and several adverse health outcomes. It has also affected education as schools and universities had to adapt to remote learning due to social isolation strategies. OBJECTIVE: to analyze the pandemic’s impact on medical education including undergraduate and graduate students and lecturers, as follow: i) teaching methods adopted by education institutes during shutdown, ii) students and lecturers’ perceptions and iii) impacts on students’ mental health. METHODS: this systematic review includes the following study designs: cross-sectional, surveys, case-control, cohort, and clinical trials. The literature search was performed in four databases: PubMed, Scopus, Embase, and SciELO . The risk of bias and the quality of the evidence were evaluated. RESULTS: a total of 1,576 articles were identified through searching databases, and 40 articles were included. We found the use of several teaching methods such as virtual platforms and social media, pre-recorded videos, discussion forums and others. Student’s challenges related to interference during online study such as family distractions, lack of a study room, challenges with internet connectivity, difficulties in communication between students and lecturers, gaps encountered during clinical skills learning. Lecturers’ challenges were difficulty in grasping students’ progress and learning outcomes and the lack of experience in online teaching. Only five studies explored mental health issues of medical students and found the occurrence of depression, anxiety, and stress. However, their prevalence was not comparable due to the use of different diagnostic instruments. CONCLUSION: there has been a wide range of teaching methods implemented for distance learning of medical students globally. The perceptions of medical students about these methods and their impact were also varied. Infrastructure, family, and curriculum problems represented the greatest difficulties in adherence and satisfaction with distance learning. However, the flexibility of digital learning was one of the factors that helped reduce these problems. Regarding mental health, the occurrence of anxiety, depression, and stress was reported

    Hydrogel-Assisted Antisense LNA Gapmer Delivery for In Situ Gene Silencing in Spinal Cord Injury

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    After spinal cord injury (SCI), nerve regeneration is severely hampered due to the establishment of a highly inhibitory microenvironment at the injury site, through the contribution of multiple factors. The potential of antisense oligonucleotides (AONs) to modify gene expression at different levels, allowing the regulation of cell survival and cell function, together with the availability of chemically modified nucleic acids with favorable biopharmaceutical properties, make AONs an attractive tool for novel SCI therapy developments. In this work, we explored the potential of locked nucleic acid (LNA)-modified AON gapmers in combination with a fibrin hydrogel bridging material to induce gene silencing in situ at a SCI lesion site. LNA gapmers were effectively developed against two promising gene targets aiming at enhancing axonal regeneration—RhoA and GSK3ß. The fibrin-matrix-assisted AON delivery system mediated potent RNA knockdown in vitro in a dorsal root ganglion explant culture system and in vivo at a SCI lesion site, achieving around 75% downregulation 5 days after hydrogel injection. Our results show that local implantation of a AON-gapmer-loaded hydrogel matrix mediated efficient gene silencing in the lesioned spinal cord and is an innovative platform that can potentially combine gene regulation with regenerative permissive substrates aiming at SCI therapeutics and nerve regeneration.This work was supported by Fundação para a Ciência e a Tecnologia ( FCT , Portugal) in the framework of the Harvard-Portugal Medical School Program ( HMSP-ICT/0020/2010 ); Project NORTE-01-0145-FEDER-000008 , supported by the Norte Portugal Regional Operational Programme (NORTE 2020) , under the PORTUGAL 2020 Partnership Agreement, through the European Regional Development Fund (ERDF) ; Fundo Europeu de Desenvolvimento Regional funds through COMPETE 2020 - Operational Program for Competitiveness and Internationalization (POCI) , Portugal 2020; by Portuguese funds through FCT/Ministério da Ciência, Tecnologia e Ensino Superior in the framework of the project “Institute for Research and Innovation in Health Sciences” ( POCI-01-0145-FEDER-007274 ); Marie Curie Actions of the European Community’s 7th Framework Program ( PIEF-GA-2011-300485 to P.M.D.M.); Santa Casa da Misericordia de Lisboa – Prémio Neurociências Mello e Castro , and FCT fellowship SFRH/BPD/108738/2015 (to P.M.D.M). Funding for open access charge: Project NORTE-01-0145-FEDER-000012 , financed by Norte Portugal Regional Operational Programme (NORTE 2020) , under the PORTUGAL 2020 Partnership Agreement, through the ERDF . We would like to acknowledge the support from Paula Magalhães and Tânia Meireles from the i3S Cell Culture and Genotyping Core Facility in real-time PCR experiments

    In vitro and in vivo characterization of PLLA-316L stainless steel electromechanical devices for bone tissue engineering—A preliminary study

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    Bone injuries represent a major social and financial impairment, commonly requiring surgical intervention due to a limited healing capacity of the tissue, particularly regarding critical-sized defects and non-union fractures. Regenerative medicine with the application of bone implants has been developing in the past decades towards the manufacturing of appropriate devices. This work intended to evaluate medical 316L stainless steel (SS)-based devices covered by a polymer poly (L-lactic acid) (PLLA) coating for bone lesion mechanical and functional support. SS316L devices were subjected to a previously described silanization process, following a three-layer PLLA film coating. Devices were further characterized and evaluated towards their cytocompatibility and osteogenic potential using human dental pulp stem cells, and biocompatibility via subcutaneous implantation in a rat animal model. Results demonstrated PLLA-SS316L devices to present superior in vitro and in vivo outcomes and suggested the PLLA coating to provide osteo-inductive properties to the device. Overall, this work represents a preliminary study on PLLA-SS316L devices’ potential towards bone tissue regenerative techniques, showing promising outcomes for bone lesion support.This work was developed within the scope of the project CICECO-Aveiro Institute of Materials, FCT Ref. UID/CTM/50011/2019, financed by national funds through the FCT/MCTES and when appropriate co-financed by FEDER under the PT2020 Partnership Agreement. This work was also financed by Portugal 2020 through the European Regional Development Fund (ERDF), in the frame of Operational Competitiveness and Internationalization Programme (POCI), in the scope of the project “Advanced BioMEMs for tissue engineering: Applications in hard tissue (BioMEMs)”, POCI-01-0145-FEDER-032095. Mariana Vieira Branquinho (SFRH/BD/146172/2019), Ana Catarina Sousa (SFRH/BD/146689/2019), and Rui Damásio Alvites (SFRH/BD/116118/2016), acknowledge FCT, for financial support

    Valorisation of red beet waste: one-step extraction and separation of betalains and chlorophylls using thermoreversible aqueous biphasic systems

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    Globally, up to 50% of root crops, fruits and vegetables produced is wasted. Beetroot stems and leaves fit into this scenario, with only a small fraction being used in cattle food. One way of approaching this problem is through their valorisation, by extracting and recovering valuable compounds present in this type of waste that could be used in other applications, while contributing towards a circular economy. In this work, a new integrated process using thermoreversible aqueous biphasic systems (ABS) composed of quaternary ammonium-based ionic liquids (ILs) and polypropyleneglycol 400 g mol−1 (PPG) is shown to allow the one-step extraction and separation of two pigment classes—betalains and chlorophylls—from red beet stems and leaves. The pigment extraction was carried out with a monophasic aqueous solution of the IL and PPG, whose phase separation was then achieved by a temperature switch, resulting in the simultaneous separation of chlorophylls and betalains into opposite phases. A central composite design was used to optimise the extraction parameters (time, temperature, and solid : liquid (S/L) ratio) of both pigment extraction yields, reaching at 20 °C, 70 min and a S/L ratio of 0.12 a maximum extraction yield of 6.67 wt% for betalains and 1.82 wt% for chlorophylls (per weight of biomass). Moreover, it is shown that aqueous solutions of ILs better stabilise betalains than the gold standard solvent used for the extraction method. Among the studied systems, the ABS comprising the IL N-ethyl-N-methyl-N,N-bis(2-hydroxyethyl) bromide ([N21(2OH)(2OH)]Br) presented the best separation performance, with an extraction efficiency of 92% and 95% for chlorophylls and betalains, respectively, for opposite phases. The pigments were removed from the respective phases using affinity resins, with high recoveries: 96% for betalains and 98% for chlorophylls, further allowing the IL reuse. Finally, the cyto- and ecotoxicities of the quaternary ammonium-based ILs were determined. The obtained results disclosed low to negligible toxicity in the thousands of mg L−1 range, with [N21(2OH)(2OH)]Br being harmless from an ecotoxicological point of view. Overall, it is shown here that the developed process is an innovative approach for the one-step extraction and selective separation of pigments contributing to the valorisation of waste biomass

    Antimicrobial activity of a library of thioxanthones and their potential as efflux pump inhibitors

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    The overexpression of efflux pumps is one of the causes of multidrug resistance, which leads to the inefficacy of drugs. This plays a pivotal role in antimicrobial resistance, and the most notable pumps are the AcrAB-TolC system (AcrB belongs to the resistance-nodulation-division family) and the NorA, from the major facilitator superfamily. In bacteria, these structures can also favor virulence and adaptation mechanisms, such as quorum-sensing and the formation of biofilm. In this study, the design and synthesis of a library of thioxanthones as potential efflux pump inhib-itors are described. The thioxanthone derivatives were investigated for their antibacterial activity and inhibition of efflux pumps, biofilm formation, and quorum-sensing. The compounds were also studied for their potential to interact with P-glycoprotein (P-gp, ABCB1), an efflux pump present in mammalian cells, and for their cytotoxicity in both mouse fibroblasts and human Caco-2 cells. The results concerning the real-time ethidium bromide accumulation may suggest a potential bacterial efflux pump inhibition, which has not yet been reported for thioxanthones. Moreover, in vitro studies in human cells demonstrated a lack of cytotoxicity for concentrations up to 20 µM in Caco-2 cells, with some derivatives also showing potential for P-gp modulation.This research was supported by national funds through FCT (Foundation for Science and Technology) within the scope of UIDB/04423/2020, UIDP/04423/2020 (Group of Natural Products and Medicinal Chemistry-CIIMAR), and under the project PTDC/SAU-PUB/28736/2017 (reference POCI-01–0145-FEDER-028736), co-financed by COMPETE 2020, Portugal 2020 and the European Union through the ERDF and by FCT through national funds and structured program of R&D&I ATLANTIDA (NORTE-01-0145-FEDER-000040), supported by NORTE2020, through ERDF, and CHIRALBIO ACTIVE-PI-3RL-IINFACTS-2019
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