221 research outputs found

    Fabrication and characterisation of a glucose-sensitive hydrogel.

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    Stimuli-responsive hydrogels are an attractive material for biosensing applications due to their biocompatibility, ability to incorporate a wide variety of biorecognition molecules and tuneable mechanical properties. In this study, a glucose-sensitive hydrogel has been developed based on the immobilization of glucose oxidase (GOx) within an ionisable polymer network. The catalysis of glucose to gluconic acid produces an acidic environment, thereby ionizing pendant basic groups of the network and generating charge along the polymer backbone. Electrostatic repulsion forces between adjacent ionized groups creates a large osmotic swelling force altering the hydrodynamic volume and permeability of the gel. The sensitivity and response time of the hydrogel were optimized via weight-based swelling studies. A linear increase in swelling was observed from 1 - 20 mM glucose (r2 = 0.9946), encompassing the physiological range of blood glucose levels. Additionally, novel electrochemical strategies to track the swelling response of these glucose -sensitive hydrogels were explored, including both using voltammetry of a bulk solution redox probe and non-faradaic electrochemical impedance spectroscopy (EIS)

    Hedgehog Signaling Pathway Database: a repository of current annotation efforts and resources for the Hh research community

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    The Hedgehog Signaling Pathway Database is a curated repository of information pertaining to the Hedgehog developmental pathway. It was designed to provide centralized access to a wide range of relevant information in an organism-agnostic manner. Data are provided for all genes and gene targets known to be involved in the Hh pathway across various organisms. The data provided include DNA and protein sequences as well as domain structure motifs. All known human diseases associated with the Hh pathway are indexed including experimental data on therapeutic agents and their molecular targets. Hh researchers will find useful information on relevant protocols, tissue cell lines and reagents used in current Hh research projects. Curated content is also provided for publications, grants and patents relating to the Hh pathway. The database can be accessed at

    Digital (Urban) Geography: Student-led research methodology training using smartphone apps

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    In the last decade, opportunities have emerged to deploy new digital technologies to research agendas and research-led teaching at third level. For instance, research methods such as surveys and questionnaires are shifting into the digital environment, while at the same time there is increasing evidence to support the view that people who have grown up with technology have acquired distinctive new ways of learning, and that traditional methodologies fail to maximise student engagement (Lafuente 2018). Thompson (2013) suggests that these ‘new learners’ are constantly using technology, multi-tasking in interactive environments, and collaborating online, yet research shows that many students are unaware of the potential of their smartphone to support learning (Woodcock et al, 2012). Despite a widespread interest in mobile devices facilitating teaching and learning in third-level education geography departments (Welsh et al. 2013), many research techniques are still taught using traditional ‘pen-and-paper’ methodologies. The ESRI Collector for ArcGIS is a mobile application (app) that can be used with iOS, Android, and Windows smartphones. Collector for ArcGIS is beginning to emerge as a technology to support spatial thinking in geography at second-level education and third-level education (Pánek and Glass 2018). Here we report on our strategy of integrating mobile technology in GG1015 Applied Geography, a large (250+) class introducing first year BA Arts Geography programme students to a number of techniques that we use in Geography. This module sits between GG1013 Environmental Geography and GG1014 Society and Space in the first-year programme. Both of these modules are a block of 24 1-hour lectures, with multiple choice quizzes (MCQs) and essay-based exams. Subsequently, GG1015 was developed to compliment these modules and introduce different teaching styles that facilitate learning across a range of diversities. Throughout this module, students engage directly in fieldwork, photographic activities, essay writing, presentations, and small group work. As such, this module offers an excellent case study to explore new techniques to engage students in learning, particularly in geographic research

    Altered retinal microRNA expression profile in a mouse model of retinitis pigmentosa

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    MicroRNA expression profiling showed that the retina of mice carrying a rhodopsin mutation that leads to retinitis pigmentosa have notably different microRNA profiles from wildtype mice; further in silico analyses identified potential retinal targets for differentially regulated microRNAs

    RUNX3 and T-Bet in Immunopathogenesis of Ankylosing Spondylitis—Novel Targets for Therapy?

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    Susceptibility to ankylosing spondylitis (AS) is polygenic with more than 100 genes identified to date. These include HLA-B27 and the aminopeptidases (ERAP1, ERAP2, and LNPEPS), which are involved in antigen processing and presentation to T-cells, and several genes (IL23R, IL6R, STAT3, JAK2, IL1R1/2, IL12B, and IL7R) involved in IL23 driven pathways of inflammation. AS is also strongly associated with polymorphisms in two transcription factors, RUNX3 and T-bet (encoded by TBX21), which are important in T-cell development and function. The influence of these genes on the pathogenesis of AS and their potential for identifying drug targets is discussed here

    Identification of Burkholderia cepacia strains that express a Burkholderia pseudomallei-like capsular polysaccharide

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    Burkholderia pseudomallei and Burkholderia cepacia are Gram-negative, soil-dwelling bacteria that are found in a wide variety of environmental niches. While B. pseudomallei is the causative agent of melioidosis in humans and animals, members of the B. cepacia complex typically only cause disease in immunocompromised hosts. In this study, we report the identification of B. cepacia strains isolated from either patients or soil in Laos and Thailand that express a B. pseudomallei-like 6-deoxyheptan capsular polysaccharide (CPS). These B. cepacia strains were initially identified based on their positive reactivity in a latex agglutination assay that uses the CPS-specific monoclonal antibody (mAb) 4B11. Mass spectrometry and recA sequencing confirmed the identity of these isolates as B. cepacia (formerly genomovar I). Total carbohydrates extracted from B. cepacia cell pellets reacted with B. pseudomallei CPS-specific mAbs MCA147, 3C5, and 4C4, but did not react with the B. pseudomallei lipopolysaccharide-specific mAb Pp-PS-W. Whole genome sequencing of the B. cepacia isolates revealed the presence of genes demonstrating significant homology to those comprising the B. pseudomallei CPS biosynthetic gene cluster. Collectively, our results provide compelling evidence that B. cepacia strains expressing the same CPS as B. pseudomallei co-exist in the environment alongside B. pseudomallei. Since CPS is a target that is often used for presumptive identification of B. pseudomallei, it is possible that the occurrence of these unique B. cepacia strains may complicate the diagnosis of melioidosis

    Reduction of Non-Specific Protein Adsorption Using Poly(ethylene) Glycol (PEG) Modified Polyacrylate Hydrogels In Immunoassays for Staphylococcal Enterotoxin B Detection

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    Three PEG molecules (PEG-methacrylate, -diacrylate and -dimethacrylate) were incorporated into galactose-based polyacrylate hydrogels and their relative abilities to reduce non-specific protein adsorption in immunoassays were determined. Highly crosslinked hydrogels containing amine-terminated functionalities were formed and used to covalently attach antibodies specific for staphylococcal enterotoxin B (SEB). Patterned arrays of immobilized antibodies in the PEG-modified hydrogels were created with a PDMS template containing micro-channels for use in sandwich immunoassays to detect SEB. Different concentrations of the toxin were applied to the hydrogel arrays, followed with a Cy3-labeled tracer antibody specific for the two toxins. Fluorescence laser scanning confocal microscopy of the tracer molecules provided both qualitative and quantitative measurements on the detection sensitivity and the reduction in non-specific binding as a result of PEG incorporation. Results showed the PEG-modified hydrogel significantly reduced non-specific protein binding with a detection limit for SEB of 1 ng/mL. Fluorescence signals showed a 10-fold decrease in the non-specific binding and a 6-fold increase in specific binding of SEB

    Incorporating new approach methodologies into regulatory nonclinical pharmaceutical safety assessment

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    © 2023 The Author(s). ALTEX. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY), https://creativecommons.org/licenses/by/4.0/New approach methodologies (NAMs) based on human biology enable the assessment of adverse biological effects of pharmaceuticals and other chemicals. Currently, however, it is unclear how NAMs should be used during drug development to improve human safety evaluation. A series of 5 workshops with 13 international experts (regulators, preclinical scientists, and NAMs developers) was conducted to identify feasible NAMs and to discuss how to exploit them in specific safety assessment contexts. Participants generated four “maps” of how NAMs can be exploited in the safety assessment of the liver, respiratory, cardiovascular, and central nervous systems. Each map shows relevant endpoints measured and tools used (e.g., cells, assays, platforms), and highlights gaps where further development and validation of NAMs remains necessary. Each map addresses the fundamental scientific requirements for the safety assessment of that organ system, providing users with guidance on the selection of appropriate NAMs. In addition to generating the maps, participants offered suggestions for encouraging greater NAM adoption within drug development and their inclusion in regulatory guidelines. A specific recommendation was that pharmaceutical companies should be more transparent about how they use NAMs in-house. As well as giving guidance for the four organ systems, the maps provide a template that could be used for additional organ safety testing contexts. Moreover, their conversion to an interactive format would enable users to drill down to the detail necessary to answer specific scientific and regulatory questions.Peer reviewe

    Incorporating new approach methodologies into regulatory nonclinical pharmaceutical safety assessment

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    New approach methodologies (NAMs) based on human biology enabletheassessment of adverse biological effects of pharmaceuticals and other chemicals. Currently,however, it is unclear how NAMsshould be usedduring drug development to improve human safety evaluation. A series of 5 workshops with 13 international experts (regulators, preclinical scientists and NAMs developers) were conducted to identify feasible NAMsand to discuss how to exploit them in specific safety assessmentcontexts. Participants generated four‘maps’of how NAMs can be exploited in the safety assessment ofthe liver, respiratory, cardiovascular,and central nervous systems. Each map showsrelevant end points measured, tools used (e.g.,cells, assays, platforms), and highlights gaps where furtherdevelopment and validation of NAMs remainsnecessary. Each map addresses the fundamental scientific requirements for the safety assessment of that organ system, providing users with guidance on the selection of appropriate NAMs. In addition to generating the maps, participants offered suggestions for encouraging greater NAM adoption within drug development and their inclusion in regulatory guidelines. A specific recommendation was that pharmaceutical companies should be more transparent about how they use NAMs in-house. As well as giving guidance for the fourorgan systems, the maps providea template that could be used for additional organ safety testing contexts.Moreover, their conversion to an interactive format would enable users to drill down to the detail necessary to answer specific scientific and regulatory questions. 1IntroductionExtensive nonclinical safety studies are undertaken on new pharmaceuticals prior to and alongside clinical trials. Their purpose is to identify and understand the toxic effects of thecompoundin order to determine whether its anticipated benefit versusrisk profile justifies clinical evaluation and, if so, to inform the design and monitoring of clinical studies. The nonclinical safety studies are mandated by regulatory guidelines and include a variety of safety pharmacologyand toxicology investigations.Safety pharmacology studies aimto determinewhether pharmaceuticalscause on-or off-target effects on biological processes which can affect the function of critical organ systems (e.g.,cardiovascular, respiratory, gastrointestinal,and central nervous systems)and to assess potency, which is needed to assess safety margins versushuman clinical drug exposure. Safety pharmacology studiesalso help informthe selectionof follow-on investigations that can aid human risk assessmentand may provide insight into mechanismswhich underlie any effectsthat arise in humans.Multiple leading pharmaceutical companies (e.g.,AstraZeneca, GlaxoSmithKline, Novartis,and Pfizer) have outlined the advantages provided by in vitrosafety pharmacological profiling, including early identification of off-target interactionsandthe prediction ofclinical side effects that may be missed in animalstudies, and have highlighted that these studies enable much more cost-effective and rapid profiling of large numbers of compounds than animal procedures (Bowes et al., 2012).Toxicology studies evaluate systemic organ toxicities, behavioraleffects, reproductive and developmental toxicology, genetic toxicology,eye irritancy and dermal sensitization. They include single and repeat dose studies in rodent and non-rodentanimal species, which identify target organs, assessseverity andreversibility,and define dose-response and no observed adverse effect levels. These are critical parameters which are essential for regulatory decision-makingon whether the compound can be progressed into clinical trials and if so, estimation ofa suitable starting dose,maximum dose, dose escalation regime,andany non-standard clinical safety monitoringthat may be needed.Toxicity observedinnonclinical animal safety studies is an important cause of the high attrition rate of candidate drugs prior to clinicaltrials that occurs inmultiple pharmaceutical companies(Cook et al., 2014).However, many drugs cause clinically serious adverseeffects in humans which are not detectedin animals(Bailey et al., 2015). For example, human drug induced liver injury(DILI),which is not detected in animal safety studies,is animportant cause of attrition late in clinical development, failed licensing and/or of restrictive drug labelling(Watkins, 2011). Attrition due to toxicity observed in animals and/or in humans isanimportant cause of the high failure rate of clinical drug development(Cook et al., 2014; Watkins, 2011; Thomas et al., 2021).New approach methodologies (NAMs)includemethods which predict and evaluate biological processes by which pharmaceuticals may elicit desirable pharmacological effects and/or may cause undesirable toxicity. Many different types of NAMs have been described. Theseinclude simple in vitrocell-based tests, more complex organotypic or microphysiologicalsystems (MPS)/organ-on-a-chipdevices,and whole human tissuesmaintained ex vivo. Interpretation ofthe invivorelevance of the data providedby these methods is complementedbycomputational toolswhichsimulate and predict in vivodrug disposition and kinetics, in particular physiologically based pharmacokinetic (PBPK) models. Accurate in vitroto in vivoextrapolation isfurther aided by human low-dose testing and microdosing studies (phase 0 testing), which provide precise data on systemic human drug exposure and kineticsin vivo
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