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1.
J Chem Educ ; 101(3): 1071-1077, 2024 Mar 12.
Artigo em Inglês | MEDLINE | ID: mdl-38495617

RESUMO

Public engagement with science is a core facet of the broader science ecosystem, in particular the science research and science education sectors. In this article we demarcate the benefits of dedicated laboratories along with practitioner advice pertaining to the design and running of a public engagement learning environment. A practicing public engagement laboratory and one that is currently being developed are used as illustrative cases to provide real-world insights to public engagement practitioners.

2.
J Biol Chem ; 298(7): 102093, 2022 07.
Artigo em Inglês | MEDLINE | ID: mdl-35654138

RESUMO

Autophagy is an essential cellular process involving degradation of superfluous or defective macromolecules and organelles as a form of homeostatic recycling. Initially proposed to be a "bulk" degradation pathway, a more nuanced appreciation of selective autophagy pathways has developed in the literature in recent years. As a glycogen-selective autophagy process, "glycophagy" is emerging as a key metabolic route of transport and delivery of glycolytic fuel substrate. Study of glycophagy is at an early stage. Enhanced understanding of this major noncanonical pathway of glycogen flux will provide important opportunities for new insights into cellular energy metabolism. In addition, glycogen metabolic mishandling is centrally involved in the pathophysiology of several metabolic diseases in a wide range of tissues, including the liver, skeletal muscle, cardiac muscle, and brain. Thus, advances in this exciting new field are of broad multidisciplinary interest relevant to many cell types and metabolic states. Here, we review the current evidence of glycophagy involvement in homeostatic cellular metabolic processes and of molecular mediators participating in glycophagy flux. We integrate information from a variety of settings including cell lines, primary cell culture systems, ex vivo tissue preparations, genetic disease models, and clinical glycogen disease states.


Assuntos
Autofagia , Glicogênio , Glicogenólise , Autofagia/fisiologia , Glicogênio/metabolismo , Macroautofagia
3.
J Pediatr Orthop ; 43(7): e519-e524, 2023 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-37193646

RESUMO

BACKGROUND: Early-onset scoliosis (EOS) is frequently associated with complex spine and chest wall deformities that may lead to severe cardiopulmonary impairment and malnutrition. The aim of this study is to evaluate the change in the nutritional status of EOS patients after treatment with magnetically controlled growing rod instrumentation (MCGR) in a single center. METHODS: We prospectively collected data of patients treated with MCGR for EOS in a single center. Exclusion criteria were <2 years' follow-up and incomplete weight-for-age Z-scores (WAZ) data. Preoperative and postoperative WAZ, radiographic parameters, including major coronal curve, kyphosis angle, space available for lung ratios, thoracic height, and unplanned returns to the operating room (UPROR), were analyzed. SD and 95% Confidence intervals (CI) are presented with means. RESULTS: Sixty-eight patients (37 males/31 females) were included. The mean age at surgery was 8.2 years (SD 2.8, range 1.8-14.2), and the mean follow-up time was 3.8 years (SD 1.0, range 2.1-6.8). The study population was categorized by the primary diagnosis as follows: 23 neuromuscular, 18 idiopathic, 15 congenital, and 12 syndromic patients. The major coronal curve improved between the preoperative and latest visits by 40% ( P <0.005, SD 27, CI 33-47), while the space available for lung ratios improved by 8% ( P <0.005, SD 13, CI 5-12). Thoracic height increased by 25% ( P <0.005, SD 13, CI 22-28), and kyphosis angle decreased by 25% ( P <0.005, SD 26, CI 9-39). Eighteen patients (27%) required a total of 53 UPRORs. WAZ improved significantly between the preoperative and the latest follow-up ( P =0.005). Regression analysis showed WAZ improvements were most significant in the underweight patients and the Idiopathic or Syndromic EOS patients. UPROR was not associated with deterioration in WAZ. CONCLUSIONS: Treatment of EOS patients with MCGR resulted in an improvement in nutritional status, as evidenced by the significant increase in WAZ. Underweight, Idiopathic and Syndromic EOS patients, and those who required UPROR all had significant improvement in their WAZ with MCGR treatment. LEVEL OF EVIDENCE: Therapeutic Study-Level II.


Assuntos
Cifose , Escoliose , Masculino , Feminino , Humanos , Lactente , Pré-Escolar , Criança , Adolescente , Escoliose/cirurgia , Seguimentos , Magreza , Resultado do Tratamento , Cifose/cirurgia , Aumento de Peso , Estudos Retrospectivos
4.
Vet Res ; 53(1): 106, 2022 Dec 12.
Artigo em Inglês | MEDLINE | ID: mdl-36510331

RESUMO

The "Zero by 30" strategic plan aims to eliminate human deaths from dog-mediated rabies by 2030 and domestic dog vaccination is a vital component of this strategic plan. In areas where domestic dog vaccination has been implemented, it is important to assess the impact of this intervention. Additionally, understanding temporal and seasonal trends in the incidence of animal rabies cases may assist in optimizing such interventions. Data on the incidence of probable rabies cases in domestic and wild animals were collected between January 2011 and December 2018 in thirteen districts of south-east Tanzania where jackals comprise over 40% of reported rabies cases. Vaccination coverage was estimated over this period, as five domestic dog vaccination campaigns took place in all thirteen districts between 2011 and 2016. Negative binomial generalized linear models were used to explore the impact of domestic dog vaccination on the annual incidence of animal rabies cases, whilst generalized additive models were used to investigate the presence of temporal and/or seasonal trends. Increases in domestic dog vaccination coverage were significantly associated with a decreased incidence of rabies cases in both domestic dogs and jackals. A 35% increase in vaccination coverage was associated with a reduction in the incidence of probable dog rabies cases of between 78.0 and 85.5% (95% confidence intervals ranged from 61.2 to 92.2%) and a reduction in the incidence of probable jackal rabies cases of between 75.3 and 91.2% (95% confidence intervals ranged from 53.0 to 96.1%). A statistically significant common seasonality was identified in the monthly incidence of probable rabies cases in both domestic dogs and jackals with the highest incidence from February to August and lowest incidence from September to January. These results align with evidence supporting the use of domestic dog vaccination as part of control strategies aimed at reducing animal rabies cases in both domestic dogs and jackals in this region. The presence of a common seasonal trend requires further investigation but may have implications for the timing of future vaccination campaigns.


Assuntos
Doenças do Cão , Vacina Antirrábica , Raiva , Animais , Cães , Humanos , Animais Domésticos , Doenças do Cão/epidemiologia , Doenças do Cão/prevenção & controle , Raiva/epidemiologia , Raiva/prevenção & controle , Raiva/veterinária , Animais Selvagens , Incidência , Vacinação/veterinária
5.
J Chem Educ ; 99(3): 1231-1237, 2022 Mar 08.
Artigo em Inglês | MEDLINE | ID: mdl-35281210

RESUMO

Public engagement in medicine has become more important in promoting population health management and literacy. Medicine is a topic of great societal importance, and many public engagement activities have been developed to promote this area. However, they often narrowly focus on patient groups, diseases, a singular pharmaceutical drug or analytical technique. Despite the importance of these activities, general audiences are still heavily reliant on doctors and pharmacists for information about their medicine and lack basic knowledge around medication use and personal safety. Given this, a broader engagement approach is warranted to target health literacy among the wider public. "Medicine Maker" is a hands-on public engagement workshop that provides audiences with the opportunity to "manufacture" and inspect the quality of proxy or "dummy" medicine through guided inquiry. Here, we detail the development of the Medicine Maker workshop from its origins in the teaching of Irish third-level pharmacy students, to its initial application with a variety of lay audiences. Formal and informal feedback from participants indicates that the workshop can help foster a more critical understanding of medicine manufacturing, quality control, and personal health.

6.
Environ Sci Technol ; 55(5): 2869-2877, 2021 03 02.
Artigo em Inglês | MEDLINE | ID: mdl-33587619

RESUMO

Atomic chlorine (Cl•) affects air quality and atmospheric oxidizing capacity. Nitryl chloride (ClNO2) - a common Cl• source-forms when chloride-containing aerosols react with dinitrogen pentoxide (N2O5). A recent study showed that saline lakebed (playa) dust is an inland source of particulate chloride (Cl-) that generates high ClNO2. However, the underlying physiochemical factors responsible for observed yields are poorly understood. To elucidate these controlling factors, we utilized single particle and bulk techniques to determine the chemical composition and mineralogy of playa sediment and dust samples from the southwest United States. Single particle analysis shows trace highly hygroscopic magnesium and calcium Cl-containing minerals are present and likely facilitate ClNO2 formation at low humidity. Single particle and mineralogical analysis detected playa sediment organic matter that hinders N2O5 uptake as well as 10 Å-clay minerals (e.g., Illite) that compete with water and chloride for N2O5. Finally, we show that the composition of the aerosol surface, rather than the bulk, is critical in ClNO2 formation. These findings underscore the importance of mixing state, competing reactions, and surface chemistry on N2O5 uptake and ClNO2 yield for playa dusts and, likely, other aerosol systems. Therefore, consideration of particle surface composition is necessary to improve ClNO2 and air quality modeling.


Assuntos
Poluição do Ar , Poeira , Aerossóis , Cloro , Carvão Mineral
7.
Oncologist ; 25(8): 641-649, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32558067

RESUMO

Since its discovery in 2007, we have seen the lives of patients diagnosed with advanced anaplastic lymphoma kinase (ALK)-rearranged non-small cell lung cancers (NSCLC) transform with the advent of molecular therapies with first-, second-, and third-generation ALK inhibitors now available in the clinic. Despite great gains in patient survival now measured in years and preserved quality of life with targeted therapies, drug resistance is unfortunately inevitably encountered in this rare and unique molecular subset of lung cancer, and patients will eventually succumb to the disease. As these patients are often young, fit, and never smokers, the clinical and scientific communities have aligned to expedite drug development and access. Drug resistance profiling and further strategies are being explored through clinical trials, including the evaluation of specific drug sequencing and combinations to overcome such resistance and promote patient longevity. The cases of this report focus on precision medicine and aim to portray the pertinent aspects to consider when treating ALK-rearranged NSCLC in 2020, an ever-shifting space. By way of case examples, this report offers valuable information to the treating clinician, including the evolution of systemic treatments and the management of oligo-progression and multisite drug resistance. With the maturation of real-world data, we are fortunate to be experiencing quality and length of life for patients with this disease surpassing prior expectations in advanced lung cancer. KEY POINTS: This report focuses on the importance of genetic analysis of serial biopsies to capture the dynamic therapeutic vulnerabilities of a patient's tumor, providing a perspective on the complexity of ALK tyrosine kinase inhibitor (ALKi) treatment sequencing. These case examples contribute to the literature on ALK-rearranged and oncogene addicted non-small cell lung cancer (NSCLC), providing a framework for care in the clinic. In oligo-progressive disease, local ablative therapy and continuation of ALKi postprogression should be considered with potential for sustained disease control. ALK G1202R kinase domain mutations (KDM), highly prevalent at resistance to second-generation ALKi resistances, may emerge in non-EML4-ALK variant 3 cases and is sensitive to third-generation lorlatinib. When in compound with one or more ALK KDMs, resistance to lorlatinib is expected. In the case of rampantly progressive disease, rebiopsy and redefining biology in a timely manner may be informative.


Assuntos
Carcinoma Pulmonar de Células não Pequenas , Neoplasias Pulmonares , Quinase do Linfoma Anaplásico/genética , Carcinoma Pulmonar de Células não Pequenas/tratamento farmacológico , Carcinoma Pulmonar de Células não Pequenas/genética , Resistencia a Medicamentos Antineoplásicos/genética , Humanos , Neoplasias Pulmonares/tratamento farmacológico , Neoplasias Pulmonares/genética , Inibidores de Proteínas Quinases/farmacologia , Inibidores de Proteínas Quinases/uso terapêutico , Qualidade de Vida
8.
Mamm Genome ; 29(11-12): 770, 2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-30370456

RESUMO

Some parts of the Abstract, Introduction and Discussion included uncited text from the following previously published chapter.

9.
Mamm Genome ; 29(11-12): 757-769, 2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-30046851

RESUMO

The antigenic landscape of the adaptive immune response is determined by the peptides presented by immune cells. In recent years, a number of immune-based cancer therapies have been shown to induce remarkable clinical responses through the activation of the patient's immune system. As a result, there is a need to identify immune biomarkers capable of predicting clinical response. Recent advances in proteomics have led to considerable developments in the more comprehensive profiling of the immune response. "Immunoproteomics" utilises a rapidly increasing collection of technologies in order to identify and quantify antigenic peptides or proteins. This includes gel-based, array-based, mass spectrometry (MS), DNA-based, or computer-based (in silico) approaches. Immunoproteomics is yielding an understanding of disease and disease progression, vaccine candidates, and biomarkers to a depth not before understood. This review gives an overview of the emerging role of proteomics in improving personalisation of immunotherapy treatment.


Assuntos
Imunidade Adaptativa/genética , Imunoterapia/tendências , Proteoma/genética , Proteômica , Simulação por Computador , Humanos , Espectrometria de Massas , Proteoma/imunologia
10.
Chemistry ; 24(2): 499-503, 2018 Jan 09.
Artigo em Inglês | MEDLINE | ID: mdl-29235704

RESUMO

A marriage made in Ireland! The Synthesis and Solid-State Pharmaceutical Centre (SSPC) transcends company and academic boundaries and is one of the largest research collaborations of its type globally. Trust, a culture of inclusivity and commitment to mutual benefit are just some of the factors that have led to the success of the SSPC. Fostering these ideals within its industry-academia, and inter-company collaborations remains crucial to further development.


Assuntos
Indústria Farmacêutica , Comunicação Interdisciplinar , Química Farmacêutica , Descoberta de Drogas , Humanos , Tecnologia Farmacêutica
11.
Clin Infect Dis ; 64(5): 666-674, 2017 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-27940946

RESUMO

Concomitant vancomycin and piperacillin/tazobactam may be associated with increased acute kidney injury (AKI) compared to vancomycin without piperacillin/tazobactam. A systematic search of Medline, Cochrane Library, and Scopus through October 2016 using ["vancomycin" and "piperacillin" and "tazobactam"] and ["AKI" or "acute renal failure" or "nephrotoxicity"] and registered meta-analysis (PROSPERO: CRD42016041646) with relevant scenarios was performed. From 307 results, fourteen observational studies totaling 3549 patients were analyzed. Concomitant vancomycin and piperacillin/tazobactam was associated with AKI in unadjusted (odds ratio (OR) 3.12, 95% confidence interval (CI) 2.04-4.78) and adjusted (aOR 3.11, 95% CI 1.77-5.47) analyses. Similar findings were seen assessing studies in adults (aOR 3.15, 95% CI 1.72-5.76), children (OR 4.55, 95% CI 2.71-10.21), and when <50% of patients received care in an intensive care unit (aOR 3.04, 95% CI 1.49-6.22) but not ≥50% (aOR 2.83, 95% CI 0.74-10.85). Increased AKI with concomitant vancomycin and piperacillin/tazobactam should be considered when determining beta-lactam therapy.

12.
Semin Cell Dev Biol ; 27: 118-27, 2014 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-24718320

RESUMO

Given the large socio-economic burden of cancer, there is an urgent need for in vivo animal cancer models that can provide a rationale for personalised therapeutic regimens that are translatable to the clinic. Recent developments in establishing mouse models that closely resemble human lung cancers involve the application of genetically engineered mouse models (GEMMs) for use in drug efficacy studies or to guide patient therapy. Here, we review recent applications of GEMMs in non-small cell lung cancer research for drug development and their potential in aiding biomarker discovery and understanding of biological mechanisms behind clinical outcomes and drug interactions.


Assuntos
Carcinoma Pulmonar de Células não Pequenas/genética , Neoplasias Pulmonares/genética , Animais , Antineoplásicos/farmacologia , Antineoplásicos/uso terapêutico , Biomarcadores Tumorais/sangue , Carcinoma Pulmonar de Células não Pequenas/sangue , Carcinoma Pulmonar de Células não Pequenas/tratamento farmacológico , Resistencia a Medicamentos Antineoplásicos , Ensaios de Seleção de Medicamentos Antitumorais , Engenharia Genética , Humanos , Neoplasias Pulmonares/sangue , Neoplasias Pulmonares/tratamento farmacológico , Camundongos Transgênicos , Terapia de Alvo Molecular , Neoplasias Experimentais/sangue , Neoplasias Experimentais/tratamento farmacológico , Neoplasias Experimentais/genética , Medicina de Precisão
13.
Appl Geochem ; 62: 131-149, 2015 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-26549929

RESUMO

Toxic metalliferous mine-tailings pose a significant health risk to ecosystems and neighboring communities from wind and water dispersion of particulates containing high concentrations of toxic metal(loid)s (e.g., Pb, As, Zn). Tailings are particularly vulnerable to erosion before vegetative cover can be reestablished, i.e., decades or longer in semi-arid environments without intervention. Metal(loid) speciation, linked directly to bioaccessibility and lability, is controlled by mineral weathering and is a key consideration when assessing human and environmental health risks associated with mine sites. At the semi-arid Iron King Mine and Humboldt Smelter Superfund site in central Arizona, the mineral assemblage of the top 2 m of tailings has been previously characterized. A distinct redox gradient was observed in the top 0.5 m of the tailings and the mineral assemblage indicates progressive transformation of ferrous iron sulfides to ferrihydrite and gypsum, which, in turn weather to form schwertmannite and then jarosite accompanied by a progressive decrease in pH (7.3 to 2.3). Within the geochemical context of this reaction front, we examined enriched toxic metal(loid)s As, Pb, and Zn with surficial concentrations 41.1, 10.7, 39.3 mM kg-1 (3080, 2200, and 2570 mg kg-1), respectively. The highest bulk concentrations of As and Zn occur at the redox boundary representing a 1.7 and 4.2 fold enrichment relative to surficial concentrations, respectively, indicating the translocation of toxic elements from the gossan zone to either the underlying redox boundary or the surface crust. Metal speciation was also examined as a function of depth using X-ray absorption spectroscopy (XAS). The deepest sample (180 cm) contains sulfides (e.g., pyrite, arsenopyrite, galena, and sphalerite). Samples from the redox transition zone (25-54 cm) contain a mixture of sulfides, carbonates (siderite, ankerite, cerrusite, and smithsonite) and metal(loid)s sorbed to neoformed secondary Fe phases, principally ferrihydrite. In surface samples (0-35 cm), metal(loid)s are found as sorbed species or incorporated into secondary Fe hydroxysulfate phases, such as schwertmannite and jarosites. Metal-bearing efflorescent salts (e.g., ZnSO4·nH2O) were detected in the surficial sample. Taken together, these data suggest the bioaccessibility and lability of metal(loid)s are altered by mineral weathering, which results in both the downward migration of metal(loid)s to the redox boundary, as well as the precipitation of metal salts at the surface.

16.
Cancers (Basel) ; 16(5)2024 Mar 06.
Artigo em Inglês | MEDLINE | ID: mdl-38473425

RESUMO

Brain cancer is a devastating and life-changing disease. Biomarkers are becoming increasingly important in addressing clinical issues, including in monitoring tumour progression and assessing survival and treatment response. The goal of this study was to identify prognostic biomarkers associated with glioma progression. Discovery proteomic analysis was performed on a small cohort of astrocytomas that were diagnosed as low-grade and recurred at a higher grade. Six proteins were chosen to be validated further in a larger cohort. Three proteins, CA9, CYFIP2, and LGALS3BP, were found to be associated with glioma progression and, in univariate analysis, could be used as prognostic markers. However, according to the results of multivariate analysis, these did not remain significant. These three proteins were then combined into a three-protein panel. This panel had a specificity and sensitivity of 0.7459 for distinguishing between long and short survival. In silico data confirmed the prognostic significance of this panel.

17.
J Asthma ; 50(1): 90-6, 2013 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-23176168

RESUMO

OBJECTIVE: Peers can play a critical role in asthma management, with attitudes toward friends with asthma hindering or supporting self-management. We explored minors' attitudes toward peers with asthma, testing if attitudes varied by grade, sex, asthma knowledge, and asthma status. METHODS: Three hundred and eighty-one students in grades 5-11 (51% female; 51% White, non-Hispanic; 12% with asthma) read five vignettes about peers with asthma, and rated the characters on 10 adjective pairs (e.g., afraid/brave and sad/happy). Three vignettes portrayed an aspect of uncontrolled asthma (asthma-related school absence, asthma-related limited physical activity, and asthma-related school nurse visit). One vignette depicted controlled asthma; one described taking medication publically. We computed a total attitude score for each vignette and a mean attitude score across the three uncontrolled vignettes. Linear regression analyses tested the effect of each predictor (grade, sex, asthma knowledge, and asthma status) on attitudes, as well as the interaction of asthma status with the remaining three predictors. RESULTS: Grade was the most robust predictor. Participants in higher grades tended to have more favorable attitudes toward peers with asthma, except for the controlled asthma vignette where participants in lower grades had more favorable attitudes. There were significant interactions between grade and asthma status for the stop-running-and-taking-medication-publically vignettes: among those with asthma, participants in higher grades had more favorable attitudes. Sex interacted with asthma status for the overall uncontrolled, absence, and stop-running vignettes; among those with asthma, girls had more favorable attitudes. CONCLUSION: With increased grade, minors have better attitudes toward peers with asthma. Living with asthma may normalize asthma. Clinicians can use grade-specific findings to counsel patients.


Assuntos
Asma/psicologia , Autocuidado/psicologia , Adolescente , Asma/terapia , Criança , Feminino , Humanos , Modelos Lineares , Masculino , Grupo Associado , Autocuidado/métodos , Autocuidado/normas , Estudantes , Inquéritos e Questionários
18.
Front Neurosci ; 17: 1001619, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36845432

RESUMO

In an effort to help elucidate the neural mechanisms underlying tinnitus in humans, researchers have often relied on animal models; a preclinical approach which ultimately required that behavioral paradigms be designed to reliably screen animals for tinnitus. Previously, we developed a two-alternative forced-choice (2AFC) paradigm for rats that allowed for the simultaneous recording of neural activity at the very moments when they were reporting the presence/absence of tinnitus. Because we first validated our paradigm in rats experiencing transient tinnitus following a high-dose of sodium salicylate, the present study now sought to evaluate its utility to screen for tinnitus caused by intense sound exposure; a common tinnitus-inducer in humans. More specifically, through a series of experimental protocols, we aimed to (1) conduct sham experiments to ensure that the paradigm was able to correctly classify control rats as not having tinnitus, (2) confirm the time course over which the behavioral testing could reliably be performed post-exposure to assess chronic tinnitus, and (3) determine if the paradigm was sensitive to the variable outcomes often observed after intense sound exposure (e.g., hearing loss with our without tinnitus). Ultimately, in accordance with our predictions, the 2AFC paradigm was indeed resistant to false-positive screening of rats for intense sound-induced tinnitus, and it was able to reveal variable tinnitus and hearing loss profiles in individual rats following intense sound exposure. Taken together, the present study documents the utility of our appetitive operant conditioning paradigm to assess acute and chronic sound-induced tinnitus in rats. Finally, based on our findings, we discuss important experimental considerations that will help ensure that our paradigm is able to provide a suitable platform for future investigations into the neural basis of tinnitus.

19.
Public Health Ethics ; 16(3): 245-260, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-38333769

RESUMO

Throughout the COVID-19 pandemic, the concept of solidarity has been invoked frequently. Much interest has centred around how citizens and communities support one another during times of uncertainty. Yet, empirical research which accounts and understands citizen's views on pandemic solidarity, or their actual practices has remained limited. Drawing upon the analysis of data from 35 qualitative interviews, this article investigates how residents in England and Scotland enacted, understood, or criticised (the lack of) solidarity during the first national lockdown in the United Kingdom in April 2020-at a time when media celebrated solidarity as being at an all-time high. It finds that although solidarity was practiced by some people, the perceived lack of solidarity was just as pronounced. We conclude that despite frequent mobilisations of solidarity by policy makers and other public actors, actual practices of solidarity are poorly understood-despite the importance of solidarity for public health and policy.

20.
J Gen Physiol ; 155(11)2023 Nov 06.
Artigo em Inglês | MEDLINE | ID: mdl-37787979

RESUMO

Transmural action potential duration differences and transmural conduction gradients aid the synchronization of left ventricular repolarization, reducing vulnerability to transmural reentry and arrhythmias. A high-fat diet and the associated accumulation of pericardial adipose tissue are linked with conduction slowing and greater arrhythmia vulnerability. It is predicted that cardiac adiposity may more readily influence epicardial conduction (versus endocardial) and disrupt normal transmural activation/repolarization gradients. The aim of this investigation was to determine whether transmural conduction gradients are modified in a rat model of pericardial adiposity. Adult Sprague-Dawley rats were fed control/high-fat diets for 15 wk. Left ventricular 300 µm tangential slices were generated from the endocardium to the epicardium, and conduction was mapped using microelectrode arrays. Slices were then histologically processed to assess fibrosis and cardiomyocyte lipid status. Conduction velocity was significantly greater in epicardial versus endocardial slices in control rats, supporting the concept of a transmural conduction gradient. High-fat diet feeding increased pericardial adiposity and abolished the transmural conduction gradient. Slowed epicardial conduction in epicardial slices strongly correlated with an increase in cardiomyocyte lipid content, but not fibrosis. The positive transmural conduction gradient reported here represents a physiological property of the ventricular activation sequence that likely protects against reentry. The absence of this gradient, secondary to conduction slowing and cardiomyocyte lipid accumulation, specifically in the epicardium, indicates a novel mechanism by which pericardial adiposity may exacerbate ventricular arrhythmias.


Assuntos
Sistema de Condução Cardíaco , Miócitos Cardíacos , Animais , Ratos , Sistema de Condução Cardíaco/fisiologia , Ratos Sprague-Dawley , Arritmias Cardíacas , Lipídeos , Potenciais de Ação/fisiologia
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