Publications by authors named "Todd Lewis"

Understanding how natural and engineered peptides enter cells would facilitate the elucidation of biochemical mechanisms underlying cell biology and is pivotal for developing effective intracellular targeting strategies. In this study, we demonstrate that our peptide stapling technique, fluorine-thiol displacement reaction (FTDR), can produce flexibly constrained peptides with significantly improved cellular uptake, particularly into the nucleus. This platform confers enhanced flexibility, which is further amplified by the inclusion of a D-amino acid, while maintaining environment-dependent α helicity, resulting in highly permeable peptides without the need for additional cell-penetrating motifs.

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Objective: To demonstrate how the new internationally comparable instrument, the People's Voice Survey, can be used to contribute the perspective of the population in assessing health system performance in countries of all levels of income.

Methods: We surveyed representative samples of populations in 16 low-, middle- and high-income countries on health-care utilization, experience and confidence during 2022-2023. We summarized and visualized data corresponding to the key domains of the World Health Organization universal health coverage framework for health system performance assessment.

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The social and behavioural determinants of COVID-19 vaccination have been described previously. However, little is known about how vaccinated people use and rate their health system. We used surveys conducted in 14 countries to study the health system correlates of COVID-19 vaccination.

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Primary health care (PHC) is central to attainment of the Sustainable Development Goals, yet comparable cross-country data on key aspects of primary care have not been widely available. This study analysed data from the People's Voice Survey, which was conducted in 2022 and 2023 in 14 countries. We documented usual source of care across countries and examined associations of usual source of care with core PHC services, quality ratings, and health system confidence.

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Despite major efforts to achieve universal health coverage (UHC), progress has lagged in many African and Asian countries. A key strategy pursued by many countries is the use of health insurance to increase access and affordability. However, evidence on insurance coverage and on the association between insurance and UHC is mixed.

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High-quality care is essential for improving health outcomes, although many health systems struggle to maintain good quality. We use data from the People's Voice Survey-a nationally representative survey conducted in 14 high-income, middle-income, and low-income countries-to describe user-reported quality of most recent health care in the past 12 months. We described ratings for 14 measures of care competence, system competence, and user experience and assessed the relationship between visit quality factors and user recommendation of the facility.

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Article Synopsis
  • A study using the People's Voice Survey in 15 countries shows that less than half of the population feels confident in their ability to access good-quality healthcare when sick.
  • Only 25% of respondents believe their current health system is functioning well and does not need major reforms, with the lowest confidence noted in countries like Peru, the UK, and Greece.
  • The survey highlights that demographic factors like wealth, education, age, and gender influence confidence levels in the health system, suggesting possible future challenges for publicly funded healthcare systems.
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This work features the use of amber suppression-mediated unnatural amino acid (UAA) incorporation into proteins for various imaging purposes. The site-specific incorporation of the UAA, p-azido-L-phenylalanine (pAzF), provides an azide handle that can be used to complete the strain promoted azide-alkyne click cycloaddition (SPAAC) reaction to introduce an imaging modality such as a fluorophore or a positron emission tomography (PET) tracer on the protein of interest (POI). Such methodology can be pursued directly in mammalian cell lines or on proteins expressed in vitro, thereby conferring a homogeneous pool of protein conjugates.

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Harris's hawk () is used for pest control, as their presence can deter wild birds such as gulls. Working Harris's hawk on UK waste sites is permitted in accordance with regulations and legislation. This study investigated the general environment of a waste site compound yard where a single Harris's hawk was flown for pest control.

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Background: Primary care is of insufficient quality in many low-income and middle-income countries. Some health facilities perform better than others despite operating in similar contexts, although the factors that characterise best performance are not well known. Existing best-performance analyses are concentrated in high-income countries and focus on hospitals.

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Primary care services are on average of low quality in Nepal. However, there is marked variation in performance of basic clinical and managerial functions between primary health care centers. The determinants of variation in primary care performance in low- and middle-income countries have been understudied relative to the prominence of primary care in national health plans.

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We demonstrated here a series of terpenoid alkaloids can be quickly prepared using semisynthesis from naturally sourced tabersonine, featuring multiple oxygen-based substituents on the indole ring such as hydroxy and methoxy groups. This panel of complex compounds enabled the exploration of indole modifications to optimize the indole alkaloids' anticancer activity, generating lead compounds (, with C15-hydroxy, C16-methoxy, and/or C17-methoxy derivatizations) that potently inhibit cancer cell line growth in the single-digit micromolar range. These results can help guide the development of terpenoid alkaloid therapeutics.

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Despite health gains over the past 30 years, children and adolescents are not reaching their health potential in many low-income and middle-income countries (LMICs). In addition to health systems, social systems, such as schools, communities, families, and digital platforms, can be used to promote health. We did a targeted literature review of how well health and social systems are meeting the needs of children in LMICs using the framework of The Lancet Global Health Commission on high-quality health systems and we reviewed evidence for structural reforms in health and social sectors.

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Article Synopsis
  • Fever and malaria are common among children under five in sub-Saharan Africa, but many don't receive adequate care due to insufficient attention to women's empowerment as a factor in healthcare seeking.
  • Using data from surveys conducted between 2010 and 2018, the study evaluated how various aspects of women's empowerment affected care utilization and the quality of care received by children with fever and malaria across 16 countries.
  • Findings revealed that over 30% of febrile children did not seek care, and those who did received low-quality care; however, higher levels of women's empowerment were linked to better care seeking and improved care quality.
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Upon deprotonation of its imidazole group at ∼pH 6, the unblocked tripeptide glycylhistidylglycine (GHG) self-assembles into very long crystalline fibrils on a 10-1000 μm scale which are capable of forming a volume spanning network, that is, hydrogel. The critical peptide concentration for self-assembly at a pH of 6 lies between 50 and 60 mM. The fraction of peptides that self-assemble into fibrils depends on the concentration of deprotonated GHG.

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The association between low-density cholesterol (LDL-C) and cardiovascular disease (CVD) is well-established, with an emphasis on lowering LDL-C levels to reduce cardiovascular events. Statin therapy has been the traditional treatment for LDL-C reduction, in addition to lifestyle modifications, but studies have shown that a substantial proportion of patients does not reach target LDL-C goals despite receiving maximally tolerated statin medications. Additionally, statin therapy is associated with a few shortcomings as many patients initiated on these medications discontinue treatment within 1 year because of lack of tolerability.

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  • The paper addresses the overlooked quality of health systems during humanitarian crises, particularly in low- and middle-income countries.
  • It involved a systematic review of studies published between 2000 and 2019, focusing on the effectiveness of health services provided during these crises.
  • Key findings reveal significant barriers to quality care, including poor diagnosis, inadequate referrals, and unique challenges such as language barriers for refugees and safety concerns for providers.
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  • The tripeptide glycyl-histidyl-glycine (GHG) can form strong hydrogels at concentrations over 40 mM when its imidazole group is deprotonated.
  • The gel exhibits a storage modulus (G') of around 50 kPa, indicating its structural strength.
  • Spectroscopic analysis shows that the gel phase contains both helically twisted β-sheets and individual monomer units coexisting together.
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  • Many patients using statins and ezetimibe still do not meet LDL-C lowering goals, leaving them at risk for cardiovascular disease despite following recommended guidelines.
  • The introduction of PCSK-9 inhibitors was a positive step in cholesterol management, but their high cost and method of administration have hindered widespread use, highlighting the need for more accessible treatments.
  • Bempedoic acid, a new investigational drug, shows promise in effectively lowering LDL-C and may serve as a valuable addition to existing therapies, especially since it avoids certain side effects of statins.
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  • Cardiovascular disease (CVD) is a major problem for patients with type 2 diabetes (T2DM), leading to high rates of illness and death.
  • Many T2DM patients are receiving treatments to prevent CVD, but significant risks still persist, especially for atherosclerotic CVD (ASCVD).
  • Recent studies indicate that certain antidiabetic drugs, particularly SGLT-2 inhibitors, show promise in reducing major adverse cardiovascular events (MACE) and may offer valuable prevention strategies for CVD in different groups of patients.
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Hypothesis: The cationic tripeptide glycylalanylglycine (GAG) self-assembles into long, thick crystalline fibrils in an ethanol/water solution. At sufficiently high concentrations, the fibrils form a volume spanning hydrogel network. We report an extensive rheology and microscopy-based study regarding the self-assembly of GAG in ethanol/water solutions to understand the conditions for fibril formation as well as the thermal stability for future developments of this material.

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Expansions of CNG microsatellite tracts are responsible for several neurodegenerative diseases, including myotonic dystrophy type 1, Huntington disease, and spinocerebellar ataxia type 8. Here we show that expanded (CNG) repeats are susceptible not only to expansions and contractions, but are prone to DNA double strand breaks following replication stress. We describe a general strategy for the construction of clonal cell lines containing CNG repeats of various lengths, in which the microsatellites are integrated using the yeast FLP recombinase at a single ectopic recombination acceptor site in the HeLa genome.

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Article Synopsis
  • Diabetes significantly increases the risk of atherosclerotic cardiovascular disease (ASCVD), leading to serious health issues for those with diabetes.
  • Effective prevention of cardiovascular complications includes managing dyslipidemia and maintaining good blood sugar control.
  • New lipid-lowering therapies, especially PCSK9 inhibitors like alirocumab, show promise in helping diabetic patients achieve their cholesterol targets when traditional therapies alone are insufficient.
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