Publications by authors named "Andrew J Smith"

229 Publications

EtSiH + KO Bu provide multiple reactive intermediates that compete in the reactions and rearrangements of benzylnitriles and indolenines.

Chem Sci 2020 Oct 21;11(45):12364-12370. Epub 2020 Oct 21.

Department of Pure and Applied Chemistry Thomas Graham Building, 295 Cathedral Street Glasgow G1 1XL UK

The combination of potassium -butoxide and triethylsilane is unusual because it generates multiple different types of reactive intermediates simultaneously that provide access to (i) silyl radical reactions, (ii) hydrogen atom transfer reactions to closed shell molecules and to radicals, (iii) electron transfer reductions and (iv) hydride ion chemistry, giving scope for unprecedented outcomes. Until now, reactions with this reagent pair have generally been explained by reference to one of the intermediates, but we now highlight the interplay and competition between them.
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http://dx.doi.org/10.1039/d0sc04244gDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8162870PMC
October 2020

New reductive rearrangement of -arylindoles triggered by the Grubbs-Stoltz reagent EtSiH/KO Bu.

Chem Sci 2020 Mar 11;11(14):3719-3726. Epub 2020 Mar 11.

Department of Pure and Applied Chemistry, University of Strathclyde 295 Cathedral Street Glasgow G1 1XL UK

-Arylindoles are transformed into dihydroacridines in a new type of rearrangement, through heating with triethylsilane and potassium butoxide. Studies indicate that the pathway involves (i) the formation of indole radical anions followed by fragmentation of the indole C2-N bond, and (ii) a ring-closing reaction that follows a potassium-ion dependent hydrogen atom transfer step. Unexpected behaviors of 'radical-trap' substrates prove very helpful in framing the proposed mechanism.
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http://dx.doi.org/10.1039/d0sc00361aDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8152433PMC
March 2020

Changes in the incidence of invasive disease due to Streptococcus pneumoniae, Haemophilus influenzae, and Neisseria meningitidis during the COVID-19 pandemic in 26 countries and territories in the Invasive Respiratory Infection Surveillance Initiative: a prospective analysis of surveillance data.

Lancet Digit Health 2021 06;3(6):e360-e370

Irish Meningitis and Sepsis Reference Laboratory, Children's Health Ireland at Temple Street, Dublin, Ireland; Royal College of Surgeons in Ireland, Beaumont Hospital, Dublin, Ireland.

Background: Streptococcus pneumoniae, Haemophilus influenzae, and Neisseria meningitidis, which are typically transmitted via respiratory droplets, are leading causes of invasive diseases, including bacteraemic pneumonia and meningitis, and of secondary infections subsequent to post-viral respiratory disease. The aim of this study was to investigate the incidence of invasive disease due to these pathogens during the early months of the COVID-19 pandemic.

Methods: In this prospective analysis of surveillance data, laboratories in 26 countries and territories across six continents submitted data on cases of invasive disease due to S pneumoniae, H influenzae, and N meningitidis from Jan 1, 2018, to May, 31, 2020, as part of the Invasive Respiratory Infection Surveillance (IRIS) Initiative. Numbers of weekly cases in 2020 were compared with corresponding data for 2018 and 2019. Data for invasive disease due to Streptococcus agalactiae, a non-respiratory pathogen, were collected from nine laboratories for comparison. The stringency of COVID-19 containment measures was quantified using the Oxford COVID-19 Government Response Tracker. Changes in population movements were assessed using Google COVID-19 Community Mobility Reports. Interrupted time-series modelling quantified changes in the incidence of invasive disease due to S pneumoniae, H influenzae, and N meningitidis in 2020 relative to when containment measures were imposed.

Findings: 27 laboratories from 26 countries and territories submitted data to the IRIS Initiative for S pneumoniae (62 837 total cases), 24 laboratories from 24 countries submitted data for H influenzae (7796 total cases), and 21 laboratories from 21 countries submitted data for N meningitidis (5877 total cases). All countries and territories had experienced a significant and sustained reduction in invasive diseases due to S pneumoniae, H influenzae, and N meningitidis in early 2020 (Jan 1 to May 31, 2020), coinciding with the introduction of COVID-19 containment measures in each country. By contrast, no significant changes in the incidence of invasive S agalactiae infections were observed. Similar trends were observed across most countries and territories despite differing stringency in COVID-19 control policies. The incidence of reported S pneumoniae infections decreased by 68% at 4 weeks (incidence rate ratio 0·32 [95% CI 0·27-0·37]) and 82% at 8 weeks (0·18 [0·14-0·23]) following the week in which significant changes in population movements were recorded.

Interpretation: The introduction of COVID-19 containment policies and public information campaigns likely reduced transmission of S pneumoniae, H influenzae, and N meningitidis, leading to a significant reduction in life-threatening invasive diseases in many countries worldwide.

Funding: Wellcome Trust (UK), Robert Koch Institute (Germany), Federal Ministry of Health (Germany), Pfizer, Merck, Health Protection Surveillance Centre (Ireland), SpID-Net project (Ireland), European Centre for Disease Prevention and Control (European Union), Horizon 2020 (European Commission), Ministry of Health (Poland), National Programme of Antibiotic Protection (Poland), Ministry of Science and Higher Education (Poland), Agencia de Salut Pública de Catalunya (Spain), Sant Joan de Deu Foundation (Spain), Knut and Alice Wallenberg Foundation (Sweden), Swedish Research Council (Sweden), Region Stockholm (Sweden), Federal Office of Public Health of Switzerland (Switzerland), and French Public Health Agency (France).
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http://dx.doi.org/10.1016/S2589-7500(21)00077-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8166576PMC
June 2021

Assessment tools for problematic opioid use in palliative care: A scoping review.

Palliat Med 2021 May 17:2692163211015567. Epub 2021 May 17.

Department of Supportive Care, Princess Margaret Cancer Centre, University Health Network, Toronto, ON, Canada.

Background: Screening for problematic opioid use is increasingly recommended in patients receiving palliative care.

Aim: To identify tools used to assess for the presence or risk of problematic opioid use in palliative care.

Design: Scoping review.

Data Sources: Bibliographic databases (inception to January 31, 2020), reference lists, and grey literature were searched to find primary studies reporting on adults receiving palliative care and prescription opioids to manage symptoms from advanced cancer, neurodegenerative diseases, or end-stage organ diseases; and included tools to assess for problematic opioid use. There were no restrictions based on study design, location, or language.

Results: We identified 42 observational studies (total 14,431 participants) published between 2009 and 2020 that used questionnaires ( = 32) and urine drug tests ( = 21) to assess for problematic opioid use in palliative care, primarily in US ( = 38) and outpatient palliative care settings ( = 36). The questionnaires were Cut down, Annoyed, Guilty, and Eye-opener (CAGE,  = 8), CAGE-Adapted to Include Drugs (CAGE-AID,  = 6), Opioid Risk Tool ( = 9), Screener and Opioid Assessment for Patients with Pain (SOAPP;  = 3), SOAPP-Revised ( = 2), and SOAPP-Short Form ( = 5). Only two studies' primary objectives were to evaluate a questionnaire's psychometric properties in patients receiving palliative care. There was wide variation in how urine drug tests were incorporated into palliative care; frequency of abnormal urine drug test results ranged from 8.6% to 70%.

Conclusion: Given the dearth of studies using tools developed or validated specifically for patients receiving palliative care, further research is needed to inform clinical practice and policy regarding problematic opioid use in palliative care.
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http://dx.doi.org/10.1177/02692163211015567DOI Listing
May 2021

Effects of Cardiotoxins on Cardiac Stem and Progenitor Cell Populations.

Authors:
Andrew J Smith

Front Cardiovasc Med 2021 27;8:624028. Epub 2021 Apr 27.

Faculty of Biological Sciences, School of Biomedical Sciences, University of Leeds, Leeds, United Kingdom.

As research and understanding of the cardiotoxic side-effects of anticancer therapy expands further and the affected patient population grows, notably the long-term survivors of childhood cancers, it is important to consider the full range of myocardial cell types affected. While the direct impacts of these toxins on cardiac myocytes constitute the most immediate damage, over the longer term, the myocardial ability to repair, or adapt to this damage becomes an ever greater component of the disease phenotype. One aspect is the potential for endogenous myocardial repair and renewal and how this may be limited by cardiotoxins depleting the cells that contribute to these processes. Clear evidence exists of new cardiomyocyte formation in adult human myocardium, along with the identification in the myocardium of endogenous stem/progenitor cell populations with pro-regenerative properties. Any effects of cardiotoxins on either of these processes will worsen long-term prognosis. While the role of cardiac stem/progenitor cells in cardiomyocyte renewal appears at best limited (although with stronger evidence of this process in response to diffuse cardiomyocyte loss), there are strong indications of a pro-regenerative function through the support of injured cell survival. A number of recent studies have identified detrimental impacts of anticancer therapies on cardiac stem/progenitor cells, with negative effects seen from both long-established chemotherapy agents such as, doxorubicin and from newer, less overtly cardiotoxic agents such as tyrosine kinase inhibitors. Damaging impacts are seen both directly, on cell numbers and viability, but also on these cells' ability to maintain the myocardium through generation of pro-survival secretome and differentiated cells. We here present a review of the identified impacts of cardiotoxins on cardiac stem and progenitor cells, considered in the context of the likely role played by these cells in the maintenance of myocardial tissue homeostasis.
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http://dx.doi.org/10.3389/fcvm.2021.624028DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8110700PMC
April 2021

Extending synchrotron SAXS instrument ranges through addition of a portable, inexpensive USAXS module with vertical rotation axes.

J Synchrotron Radiat 2021 May 19;28(Pt 3):824-833. Epub 2021 Apr 19.

Chemical Sciences, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA.

Ultra-SAXS can enhance the capabilities of existing synchrotron SAXS/WAXS beamlines. A compact ultra-SAXS module has been developed, which extends the measurable q-range with 0.0015 ≤ q (nm) ≤ 0.2, allowing structural dimensions in the range 30 ≤ D (nm) ≤ 4000 to be probed in addition to the range covered by a high-end SAXS/WAXS instrument. By shifting the module components in and out on their respective motor stages, SAXS/WAXS measurements can be easily and rapidly interleaved with USAXS measurements. The use of vertical crystal rotation axes (horizontal diffraction) greatly simplifies the construction, at minimal cost to efficiency. In this paper, the design considerations, realization and synchrotron findings are presented. Measurements of silica spheres, an alumina membrane, and a porous carbon catalyst are provided as application examples.
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http://dx.doi.org/10.1107/S1600577521003313DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8127376PMC
May 2021

Mixed hierarchical local structure in a disordered metal-organic framework.

Nat Commun 2021 Apr 6;12(1):2062. Epub 2021 Apr 6.

Department of Materials Science and Metallurgy, University of Cambridge, Cambridge, UK.

Amorphous metal-organic frameworks (MOFs) are an emerging class of materials. However, their structural characterisation represents a significant challenge. Fe-BTC, and the commercial equivalent Basolite® F300, are MOFs with incredibly diverse catalytic ability, yet their disordered structures remain poorly understood. Here, we use advanced electron microscopy to identify a nanocomposite structure of Fe-BTC where nanocrystalline domains are embedded within an amorphous matrix, whilst synchrotron total scattering measurements reveal the extent of local atomic order within Fe-BTC. We use a polymerisation-based algorithm to generate an atomistic structure for Fe-BTC, the first example of this methodology applied to the amorphous MOF field outside the well-studied zeolitic imidazolate framework family. This demonstrates the applicability of this computational approach towards the modelling of other amorphous MOF systems with potential generality towards all MOF chemistries and connectivities. We find that the structures of Fe-BTC and Basolite® F300 can be represented by models containing a mixture of short- and medium-range order with a greater proportion of medium-range order in Basolite® F300 than in Fe-BTC. We conclude by discussing how our approach may allow for high-throughput computational discovery of functional, amorphous MOFs.
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http://dx.doi.org/10.1038/s41467-021-22218-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8024318PMC
April 2021

Programming Gels Over a Wide pH Range Using Multicomponent Systems.

Angew Chem Int Ed Engl 2021 04 24;60(18):9973-9977. Epub 2021 Mar 24.

School of Chemistry, University of Glasgow, Glasgow, G12 8QQ, UK.

Multicomponent hydrogels offer a tremendous opportunity for preparing useful and exciting materials that cannot be accessed using a single component. Here, we describe an unusual multi-component low-molecular weight gelling system that exhibits pH-responsive behavior involving cooperative hydrogen bonding between the components, allowing it to maintain a gel phase across a wide pH range. Unlike traditional acid-triggered gels, our system undergoes a change in the underlying molecular packing and maintains the β-sheet structure both at acidic and basic pH. We further establish that autonomous programming between these two gel states is possible by an enzymatic reaction which allows us to prepare gels with improved mechanical properties.
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http://dx.doi.org/10.1002/anie.202101247DOI Listing
April 2021

Ion mobility mass spectrometry in the omics era: Challenges and opportunities for metabolomics and lipidomics.

Mass Spectrom Rev 2021 Feb 1. Epub 2021 Feb 1.

Department of Biochemistry and Molecular & Cellular Biology, Georgetown University, Washington, District of Columbia, USA.

Researchers worldwide are taking advantage of novel, commercially available, technologies, such as ion mobility mass spectrometry (IM-MS), for metabolomics and lipidomics applications in a variety of fields including life, biomedical, and food sciences. IM-MS provides three main technical advantages over traditional LC-MS workflows. Firstly, in addition to mass, IM-MS allows collision cross-section values to be measured for metabolites and lipids, a physicochemical identifier related to the chemical shape of an analyte that increases the confidence of identification. Second, IM-MS increases peak capacity and the signal-to-noise, improving fingerprinting as well as quantification, and better defining the spatial localization of metabolites and lipids in biological and food samples. Third, IM-MS can be coupled with various fragmentation modes, adding new tools to improve structural characterization and molecular annotation. Here, we review the state-of-the-art in IM-MS technologies and approaches utilized to support metabolomics and lipidomics applications and we assess the challenges and opportunities in this growing field.
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http://dx.doi.org/10.1002/mas.21686DOI Listing
February 2021

Controlling Protein Nanocage Assembly with Hydrostatic Pressure.

J Am Chem Soc 2020 12 30;142(49):20640-20650. Epub 2020 Nov 30.

School of Cellular and Molecular Medicine, University of Bristol, University Walk, Bristol BS8 1TD, U.K.

Controlling the assembly and disassembly of nanoscale protein cages for the capture and internalization of protein or non-proteinaceous components is fundamentally important to a diverse range of bionanotechnological applications. Here, we study the reversible, pressure-induced dissociation of a natural protein nanocage, bacterioferritin (Bfr), using synchrotron radiation small-angle X-ray scattering (SAXS) and circular dichroism (CD). We demonstrate that hydrostatic pressures of 450 MPa are sufficient to completely dissociate the Bfr 24-mer into protein dimers, and the reversibility and kinetics of the reassembly process can be controlled by selecting appropriate buffer conditions. We also demonstrate that the heme B prosthetic group present at the subunit dimer interface influences the stability and pressure lability of the cage, despite its location being discrete from the interdimer interface that is key to cage assembly. This indicates a major cage-stabilizing role for heme within this family of ferritins.
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http://dx.doi.org/10.1021/jacs.0c07285DOI Listing
December 2020

Pandemic-related mental health risk among front line personnel.

J Psychiatr Res 2021 05 4;137:673-680. Epub 2020 Nov 4.

University of Utah School of Medicine, USA; National Institute for Human Resilience, USA; Salt Lake City VA Healthcare System, USA. Electronic address:

The mental health of frontline workers is critical to a community's ability to manage crises and disasters. This study assessed risks for mental health problems (traumatic stress, depression, anxiety, alcohol use, insomnia) in association with pandemic-related stressors in a sample of emergency and hospital personnel (N = 571). Respondents completed self-report surveys online from April 1st to May 7th, 2020 in the Rocky Mountain region of the United States. Results showed that roughly fifteen to thirty percent of respondents screened positive for each disorder. Odds of screening positive were similar between groups for probable acute traumatic stress, depressive disorder, anxiety disorder, and alcohol use disorder; emergency personnel reported significantly higher rates of insufficient sleep than healthcare workers. Logistic regressions showed that respondents who reported having an immunocompromised condition had higher odds of acute traumatic stress, anxiety, and depression. Having an immunocompromised household member was associated with higher odds of insufficient sleep and anxiety. Being in a direct care provision role was associated with higher odds of screening positive for risky alcohol use. Being in a management role over direct care providers was associated with higher odds of screening positive for anxiety, risky alcohol use, and insufficient sleep. There was an inverse relationship between number of positive COVID-19 cases and anxiety, such that as positive cases went up, anxiety decreased. Overall, the mental health risks that we observed early in the COVID-19 pandemic are elevated above previous viral outbreaks (SARS) and comparable to rates shown in disasters (9/11 attacks; Hurricane Katrina).
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http://dx.doi.org/10.1016/j.jpsychires.2020.10.045DOI Listing
May 2021

Author Correction: Self-assembled poly-catenanes from supramolecular toroidal building blocks.

Nature 2020 Oct;586(7827):E6

Department of Applied Chemistry and Biotechnology, Graduate School of Engineering, Chiba University, Chiba, Japan.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.
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http://dx.doi.org/10.1038/s41586-020-2723-9DOI Listing
October 2020

Social engagement, self-efficacy, and posttraumatic stress symptoms across 6 months of psychotherapy.

J Clin Psychol 2021 Jan 6;77(1):60-77. Epub 2020 Aug 6.

Trauma, Health, & Hazards Center, University of Colorado Colorado Springs, Colorado Springs, Colorado, USA.

Objective: The current study was conducted in a naturalistic treatment setting to examine whether and how perceptions about social engagement, trauma coping self-efficacy, and posttraumatic stress symptoms (PTS) influence one another across 6 months of psychotherapy for trauma survivors.

Method: The sample included 183 clients who reported exposure to traumatic events and significant PTS (PCL-5 ≥ 33). Participants (M  = 37.8, 53.6% female) completed surveys at intake, 3 months, and 6 months into treatment. A cross-lagged panel analysis was used to test the relationships among perceived social engagement, coping self-efficacy, and PTS across three assessment points.

Results: PTS at 3-months was a mediator in the relationship between intake perceived social engagement and 6-month coping self-efficacy and between intake perceived social engagement and 6-month perceived social engagement.

Conclusions: PTS several months into treatment may serve as a mechanism between intake perceived social engagement and functional outcomes such as coping self-efficacy.
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http://dx.doi.org/10.1002/jclp.23034DOI Listing
January 2021

Self-assembled poly-catenanes from supramolecular toroidal building blocks.

Nature 2020 07 15;583(7816):400-405. Epub 2020 Jul 15.

Department of Applied Chemistry and Biotechnology, Graduate School of Engineering, Chiba University, Chiba, Japan.

Mechanical interlocking of molecules (catenation) is a nontrivial challenge in modern synthetic chemistry and materials science. One strategy to achieve catenation is the design of pre-annular molecules that are capable of both efficient cyclization and of pre-organizing another precursor to engage in subsequent interlocking. This task is particularly difficult when the annular target is composed of a large ensemble of molecules, that is, when it is a supramolecular assembly. However, the construction of such unprecedented assemblies would enable the visualization of nontrivial nanotopologies through microscopy techniques, which would not only satisfy academic curiosity but also pave the way to the development of materials with nanotopology-derived properties. Here we report the synthesis of such a nanotopology using fibrous supramolecular assemblies with intrinsic curvature. Using a solvent-mixing strategy, we kinetically organized a molecule that can elongate into toroids with a radius of about 13 nanometres. Atomic force microscopy on the resulting nanoscale toroids revealed a high percentage of catenation, which is sufficient to yield 'nanolympiadane', a nanoscale catenane composed of five interlocked toroids. Spectroscopic and theoretical studies suggested that this unusually high degree of catenation stems from the secondary nucleation of the precursor molecules around the toroids. By modifying the self-assembly protocol to promote ring closure and secondary nucleation, a maximum catenation number of 22 was confirmed by atomic force microscopy.
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http://dx.doi.org/10.1038/s41586-020-2445-zDOI Listing
July 2020

Assessment of impact of daily huddles and visual displays on medication delivery timeliness in a large academic medical center.

Am J Health Syst Pharm 2020 Jul 4. Epub 2020 Jul 4.

Department of Pharmacy, Johns Hopkins Hospital, Baltimore, MD.

Purpose: To evaluate the impact of pharmacy team huddles and near real-time performance dashboards on the punctuality of medication delivery departures from the adult inpatient pharmacy of a multihospital medical center.

Methods: Baseline delivery punctuality was established during a 2-week unannounced preintervention period, followed by the implementation of daily huddles focused on delivery timeliness along with visual displays of delivery performance metrics. The 5- to 15-minute huddles included pharmacy technicians, pharmacists, and managers. Printed visual displays that tracked hour-by-hour timeliness over the prior 24 hours were prominently displayed in the pharmacy. The primary outcome was the overall change in the percentage of punctual medication delivery departures (ie, deliveries leaving the pharmacy at the scheduled time) during the 2 weeks after implementation of huddles and visual displays (the postintervention period). Punctuality was assessed at both the day and shift levels using generalized estimating equations in a piecewise regression model. A multivariable model was constructed using a forward stepwise selection process to assess the potential impacts of workload drivers and staffing levels on medication delivery punctuality.

Results: During the pre- and postintervention periods, the punctuality of a total of 1,032 deliveries was recorded. Punctuality of deliveries across all shifts increased by 37% (95% confidence interval [CI], 18%-56% [P < 0.001]), from 50% to 87%, immediately following implementation of the huddle intervention. When punctuality was assessed by individual shift, we observed statistically significant increases for the day (35% [95% CI, 13%-57%], P = 0.002), evening (34% [95% CI, 12%-56%], P = 0.003) and night (57% [95% CI, 35%-79%], P < 0.001) shifts. During the forward stepwise multivariable model-building process, order volume, message volume, and technician staffing levels were not significantly correlated with delivery punctuality at the day or shift level.

Conclusion: Daily huddles with visual displays were successful in improving the punctuality of medication delivery departures from the pharmacy, independent of workload drivers and staffing levels.
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http://dx.doi.org/10.1093/ajhp/zxaa210DOI Listing
July 2020

Estimating upper extremity joint loads of persons with spinal cord injury walking with a lower extremity powered exoskeleton and forearm crutches.

J Biomech 2020 06 8;107:109835. Epub 2020 May 8.

Ottawa Hospital Research Institute, 505 Smyth Road, Ottawa, ON K1H8M2 Canada; University of Ottawa, Faculty of Medicine, 451 Smyth Rd, Ottawa, ON K1H8M5, Canada.

Lower extremity powered exoskeletons with crutch support can provide upright mobility to persons with complete spinal cord injury (SCI); however, crutch use for balance and weight transfer may increase upper extremity (UE) joint loads and injury risk. This research presented the first exoskeleton-human musculoskeletal model to estimate upper extremity biomechanics, driven by 3D motion data of persons with complete SCI walking with an exoskeleton and crutch assistance. Forearm crutches instrumented with strain gauges, force plates, and a 3D motion capture system were used to collect kinematic and kinetic data from five persons with complete SCI while walking with the ARKE exoskeleton. Model output estimated participant upper extremity kinematics, kinetics, and crutch forces. Compared to inverse dynamic biomechanical crutch model studies of persons with incomplete SCI, exoskeleton users walked with more anterior trunk tilt and twice the shoulder flexion angle. Anterior tilt increased forces and moments at the crutch, shoulder, and elbow. Crutch floor contact periods were 30-40% longer, resulting in upper extremity joint impulses 5 to 12 times greater than previously reported. Reducing UE joint loading is important to reduce overuse injuries associated with ambulatory assistive devices. Incorporating a variable assist ankle joint or more experience with exoskeleton walking may reduce UE joint loads, and minimise injury risk. Study outcomes provide a quantitative understanding of UE dynamics during exoskeleton walking that can be used to improve device design, training, and rehabilitation.
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http://dx.doi.org/10.1016/j.jbiomech.2020.109835DOI Listing
June 2020

A facile method for generating worm-like micelles with controlled lengths and narrow polydispersity.

Chem Commun (Camb) 2020 Jul 4;56(54):7463-7466. Epub 2020 Jun 4.

School of Chemical and Process Engineering, University of Leeds, Woodhouse Lane, Leeds, LS2 9JT, UK.

This work shows that highly uniform worm micelles formed by polymerisation induced self-assembly can be obtained via simple post-synthesis sonication. Importantly, this straightforward and versatile strategy yields exceptionally monodisperse worms with tunable aspect ratios ranging from 7.2 to 17.6 by simply changing the sonication time.
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http://dx.doi.org/10.1039/d0cc02313bDOI Listing
July 2020

Introducing Point Mutations into Human Pluripotent Stem Cells using Seamless Genome Editing.

J Vis Exp 2020 05 10(159). Epub 2020 May 10.

MRC Centre for Regenerative Medicine, University of Edinburgh;

Custom designed endonucleases, such as RNA-guided Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)-Cas9, enable efficient genome editing in mammalian cells. Here we describe detailed procedures to seamlessly genome edit the hepatocyte nuclear factor 4 alpha (HNF4α) locus as an example in human pluripotent stem cells. Combining a piggyBac-based donor plasmid and the CRISPR-Cas9 nickase mutant in a two-step genetic selection, we demonstrate correct and efficient targeting of the HNF4α locus.
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http://dx.doi.org/10.3791/61152DOI Listing
May 2020

Long-term outcomes following salvage surgery for locally recurrent rectal cancer: A 15-year follow-up study.

Eur J Surg Oncol 2020 06 10;46(6):1131-1137. Epub 2020 Mar 10.

Department of Surgical Oncology, Princess Margaret Cancer Centre and Mount Sinai Hospital, Toronto, Canada; Division of General Surgery, Department of Surgery, University of Toronto, Canada; Institute of Medical Science, University of Toronto, Toronto, Canada; Lunenfeld-Tanenbaum Research Institute, Sinai Health System, Toronto, Canada. Electronic address:

Background: Locally recurrent rectal cancer (LRRC) is a complex problem requiring multidisciplinary consultation and specialized surgical care. Given the paucity of published longer-term survival data, skepticism persists regarding the benefit of major extirpative surgery. We investigated ultra-long-term (~15 years) outcomes following radical resection of LRRC and sought relevant clinicopathologic prognostic variables.

Methods: A cohort of 52 consecutive patients who underwent resection of LRRC at our institution between 1997 and 2005 were followed with serial exams and imaging up to the point of death, or 30/06/2019.

Results: Median follow-up time was 16.5 years (9.9-18.3) for patients who were alive at last follow-up; only one patient was lost to follow-up, at 9.9 years. For the entire cohort of 52 patients, disease-specific survival (DSS) at 5, 10, and 15 years following salvage surgery was 41%, 33%, and 31%, respectively. All patients who had distant metastatic disease at the time of LRRC resection (n = 6) subsequently died of cancer, at a median of 21 months (4-46). In those without distant metastases at time of salvage surgery (n = 46), DSS at 5, 10, and 15 years was 47%, 38%, and 35%, respectively, median 60 months. Negative resection margin (R0) was independently predictive of superior outcomes. In patients with M0 disease who had R0 resection (n = 37), DSS at 5, 10 and 15 years was 58%, 47%, and 44%, respectively, median 73 months. No patient developed re-recurrence after 5.5 years.

Conclusions: This study demonstrates exceptionally durable long-term cancer-free survival following salvage surgery for LRRC, indicating that cure is possible.
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http://dx.doi.org/10.1016/j.ejso.2020.02.032DOI Listing
June 2020

Moving in for Renovations: An Innovative Solution for Replacing End-of-Life Capital Equipment. The Michael Garron Hospital-Sunnybrook Collaborative Catheterization Laboratory Project.

Healthc Q 2020 Jan;22(4):64-69

The chief of cardiology at MGH.

Replacement of an end-of-life cardiac catheterization laboratory ("cath lab") can pose a significant challenge to a hospital, particularly in single-cath-lab institutions. The disruption in patient care requires innovative approaches to minimize the inconvenience and ensure ongoing quality of care. We describe a unique approach whereby Michael Garron Hospital (MGH) "leased" a cath lab within Sunnybrook Health Sciences Centre for a 12-week period during a cath lab replacement project at MGH. The MGH cath lab and patient recovery bay remained a completely separate entity staffed by MGH nurses and physicians, with electronic connection to the home hospital. A total of 420 patients underwent cardiac catheterization with no adverse outcomes while maintaining system efficiency and high patient and staff satisfaction. Cath lab leasing involving two cooperating hospitals is an innovative and safe way to bridge a cath lab replacement.
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http://dx.doi.org/10.12927/hcq.2020.26081DOI Listing
January 2020

Reduced Susceptibility of Streptococcus pyogenes to β-Lactam Antibiotics Associated with Mutations in the Gene Is Geographically Widespread.

J Clin Microbiol 2020 03 25;58(4). Epub 2020 Mar 25.

Department of Pharmacology and Chemical Biology, Baylor College of Medicine, Houston, Texas, USA.

Recently, two related strains with reduced susceptibility to ampicillin, amoxicillin, and cefotaxime, antibiotics commonly used to treat infections, were reported. The two strains had the same nonsynonymous (amino acid-substituting) mutation in the gene, encoding penicillin-binding protein 2X (PBP2X). This concerning report led us to investigate our library of 7,025 genome sequences of type , , and clinical strains recovered from intercontinental sources for mutations in We identified 137 strains that, combined, had 37 nonsynonymous mutations in 36 codons in Although to a lesser magnitude than the two previously published isolates, many of our strains had decreased susceptibility to multiple beta-lactam antibiotics. Many mutations were found only in single strains, but 16 groups of two or more isolates of the same type had an identical amino acid replacement. Phylogenetic analysis showed that, with one exception, strains of the same type with the same amino acid replacement were clonally related by descent. This finding indicates that strains with some amino acid changes in PBP2X can successfully spread to new human hosts and cause invasive infections. Mapping of the amino acid changes onto a three-dimensional structure of the related PBP2X suggests that some substitutions are located in regions functionally important in related pathogenic bacterial species. Decreased beta-lactam susceptibility is geographically widespread in strains of numerically common gene subtypes. Enhanced surveillance and further epidemiological and molecular genetic study of this potential emergent antimicrobial problem are warranted.
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http://dx.doi.org/10.1128/JCM.01993-19DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7098749PMC
March 2020

Aspirin inhibits TGFβ2-induced epithelial to mesenchymal transition of lens epithelial cells: selective acetylation of K56 and K122 in histone H3.

Biochem J 2020 01;477(1):75-97

Sue Anschutz-Rodgers Eye Center and Department of Ophthalmology, School of Medicine, University of Colorado, Anschutz Medical Campus, Aurora, CO 80045, U.S.A.

Posterior capsule opacification (PCO) is a complication after cataract surgery that can disrupt vision. The epithelial to mesenchymal transition (EMT) of lens epithelial cells (LECs) in response to transforming growth factor β2 (TGFβ2) has been considered an obligatory mechanism for PCO. In this study, we tested the efficacy of aspirin in inhibiting the TGFβ2-mediated EMT of human LECs, LECs in human lens capsular bags, and lensectomized mice. In human LECs, the levels of the EMT markers α-smooth muscle actin (α-SMA) and fibronectin were drastically reduced by treatment with 2 mM aspirin. Aspirin also halted the EMT response of TGFβ2 when introduced after EMT initiation. In human capsular bags, treatment with 2 mM aspirin significantly suppressed posterior capsule wrinkling and the expression α-SMA in capsule-adherent LECs. The inhibition of TGFβ2-mediated EMT in human LECs was not dependent on Smad phosphorylation or MAPK and AKT-mediated signaling. We found that aspirin significantly increased the acetylation of K56 and K122 in histone H3 of human LECs. Chromatin immunoprecipitation assays using acetyl-H3K56 or acetyl-H3K122 antibody revealed that aspirin blocked the TGFβ2-induced acetylation of H3K56 and H3K122 at the promoter regions of ACTA2 and COL1A1. After lensectomy in mice, we observed an increase in the proliferation and α-SMA expression of the capsule-adherent LECs, which was ameliorated by aspirin administration through drinking water. Taken together, our results showed that aspirin inhibits TGFβ2-mediated EMT of LECs, possibly from epigenetic down-regulation of EMT-related genes.
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http://dx.doi.org/10.1042/BCJ20190540DOI Listing
January 2020

Styrene maleic acid recovers proteins from mammalian cells and tissues while avoiding significant cell death.

Sci Rep 2019 11 25;9(1):16408. Epub 2019 Nov 25.

School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Woodhouse Lane, Leeds, LS2 9JT, United Kingdom.

Detection of protein biomarkers is an important tool for medical diagnostics, typically exploiting concentration of particular biomarkers or biomarker release from tissues. We sought to establish whether proteins not normally released by living cells can be extracted without harming cells, with a view to extending this into biomarker harvest for medical diagnosis and other applications. Styrene maleic acid (SMA) is a polymer that extracts nanodiscs of biological membranes (containing membrane proteins) from cells. Hitherto it has been used to harvest SMA-lipid-membrane protein particles (SMALP) for biochemical study, by destroying the living cellular specimen. In this study, we applied SMA at low concentration to human primary cardiovascular cells and rat vascular tissue, to 'biopsy' cell proteins while avoiding significant reductions in cell viability. SMA at 6.25 parts per million harvested proteins from cells and tissues without causing significant release of cytosolic dye (calcein) or reduction in cell viability at 24 and 72 hours post-SMA (MTT assay). A wide range of proteins were recovered (20-200 kDa) and a number identified by mass spectrometry: this confirmed protein recovery from plasma membrane, intracellular membranes and cell cytosol without associated cell death. These data demonstrate the feasibility of non-lethally sampling proteins from cells, greatly extending our sampling capability, which could yield new physiological and/or pathological biomarkers.
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http://dx.doi.org/10.1038/s41598-019-51896-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6877624PMC
November 2019

Resveratrol Inhibits Wound Healing and Lens Fibrosis: A Putative Candidate for Posterior Capsule Opacification Prevention.

Invest Ophthalmol Vis Sci 2019 09;60(12):3863-3877

School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich, United Kingdom.

Purpose: Posterior capsule opacification (PCO) is a common complication of cataract surgery. In addition to improved surgical methods and IOL designs, it is likely additional agents will be needed to improve patient outcomes. Presently no pharmacological agent is in clinical use to prevent PCO. Here we investigate the putative ability of resveratrol (RESV), a naturally occurring polyphenol, as a therapeutic agent.

Methods: The human lens epithelial cell line FHL124, a human lens capsular bag model, and central anterior epithelium were used as experimental systems. Standard culture was in 5% fetal calf serum Eagle's minimum essential medium; 10 ng/mL transforming growth factor-β2 (TGFβ2) was used to induce fibrotic changes. A scratch wound assay was used to measure cell migration and the patch assay was used to assess matrix contraction by FHL124 cells. Protein expression was assessed by immunocytochemistry and Western blot and gene expression by quantitative RT-PCR. In capsular bags, cell growth across the posterior lens capsule, capsular wrinkling, and epithelial-to-mesenchymal transition were determined by image analysis.

Results: In FHL124 cells, addition of 30 μM RESV significantly impeded cell migration in a wound-healing assay. RESV significantly inhibited TGFβ2-induced expression of the myofibroblast marker alpha-smooth muscle actin (α-SMA) at both the message and protein levels, as well as significantly inhibiting matrix contraction induced by TGFβ2. In human capsular bags, 30 μM RESV significantly inhibited cell growth. TGFβ2-induced α-SMA expression and capsular wrinkling were also significantly inhibited by RESV treatment. RESV significantly suppressed expression of TGFβ2-induced genes associated with fibrotic disease, including matrix metalloproteinase-2 in FHL124 cells, capsular bags, and central anterior epithelium.

Conclusions: RESV can counter PCO-related physiological events in two human lens model systems. RESV therefore has the potential to be used as a candidate agent for the prevention of PCO, which in turn could benefit millions of cataract patients.
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http://dx.doi.org/10.1167/iovs.18-26248DOI Listing
September 2019

Gas-Phase Fragmentation of Host-Guest Complexes of Cyclodextrins and Polyoxometalates.

J Am Soc Mass Spectrom 2019 Oct 14;30(10):1934-1945. Epub 2019 Aug 14.

Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, IN, 47907, USA.

Gas-phase fragmentation pathways of host-guest complexes of cyclodextrins (CDs) and polyoxometalates (POMs) were examined using collision-induced dissociation (CID). The host-guest complexes studied here were composed of two different classes of POMs-Keggin (PWO) and Lindqvist (MO, M = Mo, W)-and three types of CDs (α-, β-, and γ-CD) differing in the diameter of the inner cavity. The CD-POM complexes were generated either by mixing methanol solutions of POM and CD or through a one-step acidic condensation of tetraoxometalates MO (M = Mo, W) with CDs for complexes with Keggin and Lindqvist anions, respectively, and introduced into the gas phase using electrospray ionization (ESI). We observe distinct differences in fragmentation pathways of the complexes of Keggin and Lindqvist POMs under high- and low-energy CID conditions. Specifically, direct dissociation and proton transfer from CD to POM accompanied by the separation of fragments is observed in CID of Keggin CD-POM complexes. In contrast, dissociation of CD complexes with Lindqvist POMs is dominated by the simultaneous loss of multiple water molecules. This unusual fragmentation channel is attributed to dissociation of the POM cluster inside the CD cavity accompanied by covalent bond formation between the fragments and CD and elimination of multiple water molecules. The observed covalent coupling of metal oxide clusters opens up opportunities for derivatization of macrocyclic host molecules using collisional excitation of gaseous non-covalent complexes.
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http://dx.doi.org/10.1007/s13361-019-02266-8DOI Listing
October 2019

A cryo-FIB lift-out technique enables molecular-resolution cryo-ET within native Caenorhabditis elegans tissue.

Nat Methods 2019 08 29;16(8):757-762. Epub 2019 Jul 29.

Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, Martinsried, Germany.

Cryo-focused ion beam milling of frozen-hydrated cells has recently provided unprecedented insights into the inner space of cells. In combination with cryo-electron tomography, this method allows access to native structures deep inside cells, enabling structural studies of macromolecules in situ. However, this approach has been mainly limited to individual cells that can be completely vitrified by plunge-freezing. Here, we describe a preparation method that is based on the targeted extraction of material from high-pressure-frozen bulk specimens with a cryo-gripper tool. This lift-out technique enables cryo-electron tomography to be performed on multicellular organisms and tissue, extending the range of applications for in situ structural biology. We demonstrate the potential of the lift-out technique with a structural study of cytosolic 80S ribosomes in a Caenorhabditis elegans worm. The preparation quality allowed for subtomogram analysis with sufficient resolution to distinguish individual ribosomal translocation states and revealed significant cell-to-cell variation in ribosome structure.
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http://dx.doi.org/10.1038/s41592-019-0497-5DOI Listing
August 2019

Association and relaxation of supra-macromolecular polymers.

Soft Matter 2019 Jul 21;15(26):5296-5307. Epub 2019 Jun 21.

Department of Chemistry, Durham University, Lower Mountjoy, South Road, Durham DH1 3LE, UK.

This paper describes the structures created by assembling functionalised entangled polymers and the effect these have on the rheology of the material. A polybutadiene (PBd) linear polymer precursor of sufficient molecular weight to be entangled is used. This is end functionalised with the self-associating group 2-ureido-4pyrimidinone (UPy). Interestingly, despite the relatively high molecular weight of the precursor diluting the UPy concentration, the effect on the material's properties is significant. To characterise the assembled microstructure we present linear rheology, extensional non-linear rheology and small angle X-ray scattering (SAXS). The linear rheology shows that the functionalised PBd assembles into large macro-structures where the terminal relaxation time is up to seven orders of magnitude larger than the precursor. The non-linear rheology shows strain-hardening over a broad range of strain-rates. We then show by both SAXS and modelling of the extensional data that there must exist clusters of UPy associations and hence assembled polymers with branched architecture. By modelling the supra-molecular structure as an effective linear polymer, we show that this would be insufficient in predicting the strain-hardening behaviour at lower extension-rates. Therefore, in this flow regime the strain-hardening is likely to be caused by branching. This is backed up by SAXS measurements which show that UPy clusters larger than pair-pair groups exist.
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http://dx.doi.org/10.1039/c8sm02580kDOI Listing
July 2019

Multiomics Analyses of HNF4α Protein Domain Function during Human Pluripotent Stem Cell Differentiation.

iScience 2019 Jun 24;16:206-217. Epub 2019 May 24.

Medical Research Council Centre for Regenerative Medicine, University of Edinburgh, 5 Little France Drive, Edinburgh, Scotland EH16 4UU, UK. Electronic address:

During mammalian development, liver differentiation is driven by signals that converge on multiple transcription factor networks. The hepatocyte nuclear factor signaling network is known to be essential for hepatocyte specification and maintenance. In this study, we have generated deletion and point mutants of hepatocyte nuclear factor-4alpha (HNF4α) to precisely evaluate the function of protein domains during hepatocyte specification from human pluripotent stem cells. We demonstrate that nuclear HNF4α is essential for hepatic progenitor specification, and the introduction of point mutations in HNF4α's Small Ubiquitin-like Modifier (SUMO) consensus motif leads to disrupted hepatocyte differentiation. Taking a multiomics approach, we identified key deficiencies in cell biology, which included dysfunctional metabolism, substrate adhesion, tricarboxylic acid cycle flux, microRNA transport, and mRNA processing. In summary, the combination of genome editing and multiomics analyses has provided valuable insight into the diverse functions of HNF4α during pluripotent stem cell entry into the hepatic lineage and during hepatocellular differentiation.
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http://dx.doi.org/10.1016/j.isci.2019.05.028DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6556878PMC
June 2019

c-kit Haploinsufficiency impairs adult cardiac stem cell growth, myogenicity and myocardial regeneration.

Cell Death Dis 2019 06 4;10(6):436. Epub 2019 Jun 4.

Molecular and Cellular Cardiology, Department of Experimental and Clinical Medicine, Magna Graecia University, Catanzaro, 88100, Italy.

An overdose of Isoproterenol (ISO) causes acute cardiomyocyte (CM) dropout and activates the resident cardiac c-kit stem/progenitor cells (CSCs) generating a burst of new CM formation that replaces those lost to ISO. Recently, unsuccessful attempts to reproduce these findings using c-kit knock-in (KI) mouse models were reported. We tested whether c-kit haploinsufficiency in c-kitKI mice was the cause of the discrepant results in response to ISO. Male C57BL/6J wild-type (wt) mice and c-kitKI mice were given a single dose of ISO (200 and/or 400 mg/Kg s.c.). CM formation was measured with different doses and duration of BrdU or EdU. We compared the myogenic and regenerative potential of the c-kitCSCs with wtCSCs. Acute ISO overdose causes LV dysfunction with dose-dependent CM death by necrosis and apoptosis, whose intensity follows a basal-apical and epicardium to sub-endocardium gradient, with the most severe damage confined to the apical sub-endocardium. The damage triggers significant new CM formation mainly in the apical sub-endocardial layer. c-kit haploinsufficiency caused by c-kitKIs severely affects CSCs myogenic potential. c-kitKI mice post-ISO fail to respond with CSC activation and show reduced CM formation and suffer chronic cardiac dysfunction. Transplantation of wtCSCs rescued the defective regenerative cardiac phenotype of c-kitKI mice. Furthermore, BAC-mediated transgenesis of a single c-kit gene copy normalized the functional diploid c-kit content of c-kitKI CSCs and fully restored their regenerative competence. Overall, these data show that c-kit haploinsufficiency impairs the endogenous cardioregenerative response after injury affecting CSC activation and CM replacement. Repopulation of c-kit haploinsufficient myocardial tissue with wtCSCs as well c-kit gene deficit correction of haploinsufficient CSCs restores CM replacement and functional cardiac repair. Thus, adult neo-cardiomyogenesis depends on and requires a diploid level of c-kit.
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http://dx.doi.org/10.1038/s41419-019-1655-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6547756PMC
June 2019