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1.
Physiol Rep ; 12(8): e15993, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38627215

RESUMO

Metabolic dysfunction-associated steatotic liver disease (MASLD) is a major public health issue with a worldwide prevalence of 30%-32%. In animal models, voluntary exercise may be an alternative to forced physical activity, avoiding stress, potential injuries, and being logistically simpler. Here, we assessed voluntary exercise (Vex) in Sprague-Dawley rats fed a high-fat, high-cholesterol diet for 18 weeks to induce MASLD. We quantified workload (speed and distance) using exercise wheels and evaluated energy expenditure using calorimetric cages. MASLD progression was assessed using circulating and hepatic biochemical and gene markers of steatosis, inflammation, and fibrosis. The animals ran an average of 301 km during the study period, with the average daily distance peaking at 4937 m/day during Weeks 3-4 before decreasing to 757 m/day by the end of the study. Rats exposed to Vex showed no improvement in any of the MASLD-associated features, such as steatosis, inflammation, or fibrosis. Rats exposed to Vex exhibited a higher total energy expenditure during the night phase (+0.35 kcal/h; p = 0.003) without resulting in any effect on body composition. We conclude that, in our experimental conditions, Vex failed to prevent MASLD progression in male Sprague-Dawley rats exposed to a high-fat high-cholesterol diet for 18 weeks.


Assuntos
Fígado Gorduroso , Doenças Metabólicas , Ratos , Masculino , Animais , Ratos Sprague-Dawley , Fígado Gorduroso/metabolismo , Dieta Hiperlipídica/efeitos adversos , Colesterol , Inflamação , Exercício Físico , Fibrose , Progressão da Doença
2.
Can J Neurol Sci ; : 1-9, 2024 Mar 27.
Artigo em Inglês | MEDLINE | ID: mdl-38532570

RESUMO

OBJECTIVE: To examine the association of co-morbidity with home-time after acute stroke and whether the association is influenced by age. METHODS: We conducted a province-wide study using linked administrative databases to identify all admissions for first acute ischemic stroke or intracerebral hemorrhage between 2007 and 2018 in Alberta, Canada. We used ischemic stroke-weighted Charlson Co-morbidity Index of 3 or more to identify those with severe co-morbidity. We used zero-inflated negative binomial models to determine the association of severe co-morbidity with 90-day and 1-year home-time, and logistic models for achieving ≥ 80 out of 90 days of home-time, assessing for effect modification by age and adjusting for sex, stroke type, comprehensive stroke center care, hypertension, atrial fibrillation, year of study, and separately adjusting for estimated stroke severity. We also evaluated individual co-morbidities. RESULTS: Among 28,672 patients in our final cohort, severe co-morbidity was present in 27.7% and was associated with lower home-time, with a greater number of days lost at younger age (-13 days at age < 60 compared to -7 days at age 80+ years for 90-day home-time; -69 days at age < 60 compared to -51 days at age 80+ years for 1-year home-time). The reduction in probability of achieving ≥ 80 days of home-time was also greater at younger age (-22.7% at age < 60 years compared to -9.0% at age 80+ years). Results were attenuated but remained significant after adjusting for estimated stroke severity and excluding those who died. Myocardial infarction, diabetes, and cancer/metastases had a greater association with lower home-time at younger age, and those with dementia had the greatest reduction in home time. CONCLUSION: Severe co-morbidity in acute stroke is associated with lower home-time, more strongly at younger age.

3.
Epilepsia ; 2024 Mar 28.
Artigo em Inglês | MEDLINE | ID: mdl-38546705

RESUMO

OBJECTIVES: Amygdala enlargement is detected on magnetic resonance imaging (MRI) in some patients with drug-resistant temporal lobe epilepsy (TLE), but its clinical significance remains uncertain We aimed to assess if the presence of amygdala enlargement (1) predicted seizure outcome following anterior temporal lobectomy with amygdalohippocampectomy (ATL-AH) and (2) was associated with specific histopathological changes. METHODS: This was a case-control study. We included patients with drug-resistant TLE who underwent ATL-AH with and without amygdala enlargement detected on pre-operative MRI. Amygdala volumetry was done using FreeSurfer for patients who had high-resolution T1-weighted images. Mann-Whitney U test was used to compare pre-operative clinical characteristics between the two groups. The amygdala volume on the epileptogenic side was compared to the amygdala volume on the contralateral side among cases and controls. Then, we used a two-sample, independent t test to compare the means of amygdala volume differences between cases and controls. The chi-square test was used to assess the correlation of amygdala enlargement with (1) post-surgical seizure outcomes and (2) histopathological changes. RESULTS: Nineteen patients with and 19 patients without amygdala enlargement were studied. Their median age at surgery was 38 years for cases and 39 years for controls, and 52.6% were male. There were no statistically significant differences between the two groups in their pre-operative clinical characteristics. There were significant differences in the means of volume difference between cases and controls (Diff = 457.2 mm3, 95% confidence interval [CI] 289.6-624.8; p < .001) and in the means of percentage difference (p < .001). However, there was no significant association between amygdala enlargement and surgical outcome (p = .72) or histopathological changes (p = .63). SIGNIFICANCE: The presence of amygdala enlargement on the pre-operative brain MRI in patients with TLE does not affect the surgical outcome following ATL-AH, and it does not necessarily suggest abnormal histopathology. These findings suggest that amygdala enlargement might reflect a secondary reactive process to seizures in the epileptogenic temporal lobe.

4.
Thromb Res ; 236: 108-116, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38422980

RESUMO

BACKGROUND: The risk of venous thromboembolism (VTE) is increased postpartum and contributes to important morbidity and mortality. While there have been advances in evaluating diagnostic algorithms for suspected VTE during pregnancy, there is limited data for postpartum individuals. OBJECTIVE: We conducted a scoping review to describe and evaluate diagnostic strategies used to investigate suspected VTE in postpartum individuals. METHODS: A comprehensive search strategy was conducted in Ovid MEDLINE, Embase and the Cochrane Central Register of Controlled Trials (January 1, 2000-September 30, 2022) to identify original articles that reported on diagnostic strategies in postpartum individuals with suspected VTE. We extracted demographics, clinical decision rules used, D-dimer and imaging completed, including test performance and VTE outcomes. RESULTS: A total of 13 studies conducted across 11 countries with separate postpartum data were included for 759 individuals with suspected PE (n = 634) or DVT (n = 125), including unpublished data (n = 251). Among those with suspected PE, computed tomography pulmonary angiography was conducted more commonly (n = 522) than ventilation-perfusion scans (n = 69), with PE positivity rates that ranged from 4 %-27.6 % and 0-50 % across studies, respectively. Among 131 postpartum individuals with suspected PE who had a D-dimer measured, only 4.6 % (6/131) had a negative D-dimer test. For postpartum individuals with suspected DVT, the most common diagnostic test was compression ultrasonography (positivity rate 12.2 %-18.6 %). There were limited retrospective data evaluating the clinical decision rules. CONCLUSIONS: There are heterogeneous approaches globally in the diagnosis of suspected postpartum VTE. Limited high-quality data available underscores the need for more robust evidence to inform clinical practice.


Assuntos
Embolia Pulmonar , Tromboembolia Venosa , Trombose Venosa , Gravidez , Feminino , Humanos , Tromboembolia Venosa/diagnóstico , Trombose Venosa/diagnóstico , Estudos Retrospectivos , Produtos de Degradação da Fibrina e do Fibrinogênio , Período Pós-Parto , Ultrassonografia , Embolia Pulmonar/diagnóstico
5.
Science ; 383(6685): 860-864, 2024 Feb 23.
Artigo em Inglês | MEDLINE | ID: mdl-38386743

RESUMO

Forestation is widely proposed for carbon dioxide (CO2) removal, but its impact on climate through changes to atmospheric composition and surface albedo remains relatively unexplored. We assessed these responses using two Earth system models by comparing a scenario with extensive global forest expansion in suitable regions to other plausible futures. We found that forestation increased aerosol scattering and the greenhouse gases methane and ozone following increased biogenic organic emissions. Additionally, forestation decreased surface albedo, which yielded a positive radiative forcing (i.e., warming). This offset up to a third of the negative forcing from the additional CO2 removal under a 4°C warming scenario. However, when forestation was pursued alongside other strategies that achieve the 2°C Paris Agreement target, the offsetting positive forcing was smaller, highlighting the urgency for simultaneous emission reductions.

6.
Med Sci Sports Exerc ; 56(1): 63-72, 2024 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-37703030

RESUMO

PURPOSE: Using a replicated crossover design, we quantified the response heterogeneity of postprandial cardiovascular disease risk marker responses to acute exercise. METHODS: Twenty men (mean (SD) age, 26 (6) yr; body mass index, 23.9 (2.4) kg·m -2 ) completed four 2-d conditions (two control, two exercise) in randomized orders. On days 1 and 2, participants rested and consumed two high-fat meals over 9 h. Participants ran for 60 min (61 (7)% of peak oxygen uptake) on day 1 (6.5 to 7.5 h) of both exercise conditions. Time-averaged total area under the curve (TAUC) for triacylglycerol, glucose, and insulin were calculated from 11 venous blood samples on day 2. Arterial stiffness and blood pressure responses were calculated from measurements at baseline on day 1 and at 2.5 h on day 2. Consistency of individual differences was explored by correlating the two replicates of control-adjusted exercise responses for each outcome. Within-participant covariate-adjusted linear mixed models quantified participant-by-condition interactions and individual response SDs. RESULTS: Acute exercise reduced mean TAUC-triacylglycerol (-0.27 mmol·L -1 ·h; Cohen's d = 0.29, P = 0.017) and TAUC-insulin (-25 pmol·L -1 ·h; Cohen's d = 0.35, P = 0.022) versus control, but led to negligible changes in TAUC-glucose and the vascular outcomes (Cohen's d ≤ 0.36, P ≥ 0.106). Small-to-moderate, but nonsignificant, correlations were observed between the two response replicates ( r = -0.42 to 0.15, P ≥ 0.066). We did not detect any individual response heterogeneity. All participant-by-condition interactions were P ≥ 0.137, and all individual response SDs were small with wide 95% confidence intervals overlapping zero. CONCLUSIONS: Large trial-to-trial within-subject variability inhibited detection of consistent interindividual variability in postprandial metabolic and vascular responses to acute exercise.


Assuntos
Doenças Cardiovasculares , Masculino , Humanos , Adulto , Estudos Cross-Over , Exercício Físico/fisiologia , Triglicerídeos , Glucose , Insulina , Período Pós-Prandial/fisiologia , Glicemia/metabolismo
7.
BMJ Open ; 13(10): e073453, 2023 10 27.
Artigo em Inglês | MEDLINE | ID: mdl-37890973

RESUMO

INTRODUCTION: The physical health of individuals with severe mental illness (SMI) is a cause for concern. While the purpose of inpatient mental health settings is rehabilitation and treatment, the physical health of hospitalised patients commonly deteriorates. Physical activity (PA) has been identified as an appropriate intervention to help improve the psychological and physical health of inpatients. We aim to address the gaps in the current literature by exploring how, why, for whom and in what contexts PA interventions help patients with SMI, who receive inpatient treatment, to increase their PA engagement. METHODS AND ANALYSIS: Realist synthesis: Six steps will be followed: (1) identification of the review question and scope of the review; (2) searching for evidence; (3) screening and appraisal; (4) extraction of data; (5) synthesis of the data and (6) dissemination. Five databases will be searched: Web of Science, PubMed, PsycINFO, PsychArticles and EmBase. A total of 10-15 stakeholders made up of academics and people living with SMI, sport and exercise therapists, psychiatrists, physiotherapists of low, medium and highly secure inpatient settings, will form an expert advisory group. They will provide their insight and knowledge of the secure setting contexts and perceived principles of how PA initiatives being undertaken in their hospitals for patients with SMI work, or not. The results will be published in accordance with the Realist And Meta-narrative Evidence Syntheses-Evolving Standards publication standards. ETHICS AND DISSEMINATION: Ethical approval has been granted. The review will produce context-specific guidance for Clinical Commissioning Groups and practitioners on how to optimise the provision of PA interventions for people with SMI in inpatient settings.


Assuntos
Transtornos Mentais , Psiquiatria , Humanos , Saúde Mental , Pacientes Internados , Transtornos Mentais/terapia , Exercício Físico
8.
Sensors (Basel) ; 23(17)2023 Aug 25.
Artigo em Inglês | MEDLINE | ID: mdl-37687871

RESUMO

Continuous glucose monitoring (CGM) is used clinically and for research purposes to capture glycaemic profiles. The accuracy of CGM among healthy populations has not been widely assessed. This study assessed agreement between glucose concentrations obtained from venous plasma and from CGM (FreeStyle Libre2TM, Abbott Diabetes Care, Witney, UK) in healthy women. Glucose concentrations were assessed after fasting and every 15 min after a standardized breakfast over a 4-h lab period. Accuracy of CGM was determined by Bland-Altman plot, 15/15% sensor agreement analysis, Clarke error grid analysis (EGA) and mean absolute relative difference (MARD). In all, 429 valid CGM readings with paired venous plasma glucose (VPG) values were obtained from 29 healthy women. Mean CGM readings were 1.14 mmol/L (95% CI: 0.97 to 1.30 mmol/L, p < 0.001) higher than VPG concentrations. Ratio 95% limits of agreement were from 0.68 to 2.20, and a proportional bias (slope: 0.22) was reported. Additionally, 45% of the CGM readings were within ±0.83 mmol/L (±15 mg/dL) or ±15% of VPG, while 85.3% were within EGA Zones A + B (clinically acceptable). MARD was 27.5% (95% CI: 20.8, 34.2%), with higher MARD values in the hypoglycaemia range and when VPG concentrations were falling. The FreeStyle Libre2TM CGM system tends to overestimate glucose concentrations compared to venous plasma samples in healthy women, especially during hypoglycaemia and during glycaemic swings.


Assuntos
Glucose , Hipoglicemia , Humanos , Feminino , Glicemia , Automonitorização da Glicemia , Testes Hematológicos
9.
Int J Obes (Lond) ; 47(11): 1171-1177, 2023 11.
Artigo em Inglês | MEDLINE | ID: mdl-37553452

RESUMO

BACKGROUND/OBJECTIVES: While the physiology of obesity has been so extensively investigated to date, only an extremely small number of studies (less than 50) have focused on the other extremity of the weight spectrum: constitutional thinness. Yet, this important state of underweight in the absence of any eating disorders provides a mirror model of obesity that might be particularly insightful in understanding obesity. Nevertheless, important methodological and recruitment-related issues appear when it comes to this complex constitutionally thin phenotype, as experienced by our research group with the realization of the ongoing NUTRILEAN clinical trial. To face this challenge, the present paper aims at identifying, analyzing, and discussing the quality of such recruitment processes in publications about constitutional thinness. METHODS: In this order, a group of experts collectively created a new grading system to assess the level of rigour and quality achieved by each study based on different criteria. RESULTS: The main results were that (i) metabolic-related biasing criteria were poorly observed despite being crucial, (ii) recruitment processes were not detailed enough and with sufficient explicitness, and (iii) recruiting among already identified patients would be associated with both higher sample sizes and better scores of quality. CONCLUSIONS: The present work encourages investigators to adopt a high level of rigour despite the complexity and duration of recruitment processes for this specific population, and readers to pay close attention to the quality of recruitment when interpreting the data. To better understand obesity and its physiological adaptations, it seems essential not only to compare it to normal-weight conditions, but also to the other extremity of the weight status spectrum represented by constitutional thinness.


Assuntos
Transtornos da Alimentação e da Ingestão de Alimentos , Magreza , Humanos , Magreza/epidemiologia , Obesidade , Extremidades
10.
Int J Obes (Lond) ; 47(10): 1000-1007, 2023 10.
Artigo em Inglês | MEDLINE | ID: mdl-37491534

RESUMO

BACKGROUND/OBJECTIVES: Inadequate movement, excess adiposity, and insulin resistance augment cardiometabolic risk. This study examined the associations of objectively measured moderate-to-vigorous intensity physical activity (MVPA), sedentary time and cardiorespiratory fitness (CRF), with adipose tissue insulin resistance and ectopic fat. METHODS: Data were combined from two previous experimental studies with community volunteers (n = 141, male = 60%, median (interquartile range) age = 37 (19) years, body mass index (BMI) = 26.1 (6.3) kg·m-2). Adipose tissue insulin resistance was assessed using the adipose tissue insulin resistance index (Adipo-IR); whilst magnetic resonance imaging (MRI) was used to measure liver, visceral (VAT) and subcutaneous abdominal adipose tissue (ScAT). Sedentary time and MVPA were measured via an ActiGraph GT3X+ accelerometer. Generalized linear models examined the association of CRF, MVPA, and sedentary time with Adipo-IR and fat depots. Interaction terms explored the moderating influence of age, sex, BMI and CRF. RESULTS: After controlling for BMI and cardiometabolic variables, sedentary time was positively associated with Adipo-IR (ß = 0.68 AU [95%CI = 0.27 to 1.10], P < 0.001). The association between sedentary time and Adipo-IR was moderated by age, CRF and BMI; such that it was stronger in individuals who were older, had lower CRF and had a higher BMI. Sedentary time was also positively associated with VAT (ß = 0.05 L [95%CI = 0.01 to 0.08], P = 0.005) with the relationship being stronger in females than males. CRF was inversely associated with VAT (ß = -0.02 L [95%CI = -0.04 to -0.01], P = 0.003) and ScAT (ß = -0.10 L [95%CI = -0.13 to -0.06], P < 0.001); with sex and BMI moderating the strength of associations with VAT and ScAT, respectively. CONCLUSIONS: Sedentary time is positively associated with adipose tissue insulin resistance which regulates lipogenesis and lipolysis. CRF is independently related to central fat storage which is a key risk factor for cardiometabolic disease.


Assuntos
Aptidão Cardiorrespiratória , Doenças Cardiovasculares , Resistência à Insulina , Feminino , Humanos , Masculino , Adulto , Aptidão Cardiorrespiratória/fisiologia , Comportamento Sedentário , Exercício Físico/fisiologia , Índice de Massa Corporal , Tecido Adiposo , Aptidão Física
11.
J Stroke Cerebrovasc Dis ; 32(8): 107236, 2023 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-37429113

RESUMO

OBJECTIVE: To examine whether the association of co-morbidity with mortality after acute stroke is influenced by stroke type, age, sex, or time since stroke. MATERIALS AND METHODS: We conducted a province-wide population-based study using linked administrative databases to identify all admissions for acute stroke between 2007-2018 in Alberta, Canada. We used Cox proportional hazard models to determine the association of severe co-morbidity based on the Charlson Co-morbidity Index with 1-year mortality after stroke, assessing for effect modification by stroke type, age, and sex, and with adjustment for estimated stroke severity, comprehensive stroke centre care, hypertension, atrial fibrillation, and year of study. We used a piecewise model to analyze the impact of co-morbidity across four time periods. RESULTS: We had 28,672 patients in our final cohort (87.8% ischemic stroke). The hazard of mortality with severe co-morbidity was higher for individuals with ischemic stroke (adjusted hazard ratio [aHR] 2.20, 95% CI 2.07-2.32) compared to those with intracerebral hemorrhage (aHR 1.70, 95% CI 1.51-1.92; pint<0.001), and higher in individuals under age 75 (aHR 3.20, 95% CI 2.90-3.53) compared to age ≥75 (aHR 1.93, 95% CI 1.82-2.05, pint<0.001). There was no interaction by sex. The hazard ratio increased in a graded fashion at younger ages and was higher after the first 30 days of acute stroke. CONCLUSION: There was a stronger association between co-morbidity and mortality at younger age and in the subacute phase of stroke. Further research is needed to determine the reason for these findings and identify ways to improve outcomes among those with stroke and co-morbid conditions at young age.

12.
Front Med (Lausanne) ; 10: 1149922, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37293307

RESUMO

Introduction: Two million people in the UK are experiencing long COVID (LC), which necessitates effective and scalable interventions to manage this condition. This study provides the first results from a scalable rehabilitation programme for participants presenting with LC. Methods: 601 adult participants with symptoms of LC completed the Nuffield Health COVID-19 Rehabilitation Programme between February 2021 and March 2022 and provided written informed consent for the inclusion of outcomes data in external publications. The 12-week programme included three exercise sessions per week consisting of aerobic and strength-based exercises, and stability and mobility activities. The first 6 weeks of the programme were conducted remotely, whereas the second 6 weeks incorporated face-to-face rehabilitation sessions in a community setting. A weekly telephone call with a rehabilitation specialist was also provided to support queries and advise on exercise selection, symptom management and emotional wellbeing. Results: The 12-week rehabilitation programme significantly improved Dyspnea-12 (D-12), Duke Activity Status Index (DASI), World Health Orginaisation-5 (WHO-5) and EQ-5D-5L utility scores (all p < 0.001), with the 95% confidence intervals (CI) for the improvement in each of these outcomes exceeding the minimum clinically important difference (MCID) for each measure (mean change [CI]: D-12: -3.4 [-3.9, -2.9]; DASI: 9.2 [8.2, 10.1]; WHO-5: 20.3 [18.6, 22.0]; EQ-5D-5L utility: 0.11 [0.10, 0.13]). Significant improvements exceeding the MCID were also observed for sit-to-stand test results (4.1 [3.5, 4.6]). On completion of the rehabilitation programme, participants also reported significantly fewer GP consultations (p < 0.001), sick days (p = 0.003) and outpatient visits (p = 0.007) during the previous 3 months compared with baseline. Discussion: The blended and community design of this rehabilitation model makes it scalable and meets the urgent need for an effective intervention to support patients experiencing LC. This rehabilitation model is well placed to support the NHS (and other healthcare systems worldwide) in its aim of controlling the impacts of COVID-19 and delivering on its long-term plan. Clinical trial registration: https://www.isrctn.com/ISRCTN14707226, identifier 14707226.

13.
Hum Brain Mapp ; 44(9): 3815-3832, 2023 06 15.
Artigo em Inglês | MEDLINE | ID: mdl-37145965

RESUMO

Acute exercise suppresses appetite and alters food-cue reactivity, but the extent exercise-induced changes in cerebral blood flow (CBF) influences the blood-oxygen-level-dependent (BOLD) signal during appetite-related paradigms is not known. This study examined the impact of acute running on visual food-cue reactivity and explored whether such responses are influenced by CBF variability. In a randomised crossover design, 23 men (mean ± SD: 24 ± 4 years, 22.9 ± 2.1 kg/m2 ) completed fMRI scans before and after 60 min of running (68% ± 3% peak oxygen uptake) or rest (control). Five-minute pseudo-continuous arterial spin labelling fMRI scans were conducted for CBF assessment before and at four consecutive repeat acquisitions after exercise/rest. BOLD-fMRI was acquired during a food-cue reactivity task before and 28 min after exercise/rest. Food-cue reactivity analysis was performed with and without CBF adjustment. Subjective appetite ratings were assessed before, during and after exercise/rest. Exercise CBF was higher in grey matter, the posterior insula and in the region of the amygdala/hippocampus, and lower in the medial orbitofrontal cortex and dorsal striatum than control (main effect trial p ≤ .018). No time-by-trial interactions for CBF were identified (p ≥ .087). Exercise induced moderate-to-large reductions in subjective appetite ratings (Cohen's d = 0.53-0.84; p ≤ .024) and increased food-cue reactivity in the paracingulate gyrus, hippocampus, precuneous cortex, frontal pole and posterior cingulate gyrus. Accounting for CBF variability did not markedly alter detection of exercise-induced BOLD signal changes. Acute running evoked overall changes in CBF that were not time dependent and increased food-cue reactivity in regions implicated in attention, anticipation of reward, and episodic memory independent of CBF.


Assuntos
Sinais (Psicologia) , Corrida , Humanos , Masculino , Encéfalo/fisiologia , Circulação Cerebrovascular/fisiologia , Imageamento por Ressonância Magnética/métodos , Oxigênio , Estudos Cross-Over
14.
Materials (Basel) ; 16(10)2023 May 18.
Artigo em Inglês | MEDLINE | ID: mdl-37241431

RESUMO

Extensive studies have been conducted on utilising natural fibres as reinforcement in composite production. All-polymer composites have attracted much attention because of their high strength, enhanced interfacial bonding and recyclability. Silks, as a group of natural animal fibres, possess superior properties, including biocompatibility, tunability and biodegradability. However, few review articles are found on all-silk composites, and they often lack comments on the tailoring of properties through controlling the volume fraction of the matrix. To better understand the fundamental basis of the formation of silk-based composites, this review will discuss the structure and properties of silk-based composites with a focus on employing the time-temperature superposition principle to reveal the corresponding kinetic requirements of the formation process. Additionally, a variety of applications derived from silk-based composites will be explored. The benefits and constraints of each application will be presented and discussed. This review paper will provide a useful overview of research on silk-based biomaterials.

15.
Neurosci Biobehav Rev ; 152: 105247, 2023 09.
Artigo em Inglês | MEDLINE | ID: mdl-37236384

RESUMO

This systematic review examined whether neural responses to visual food-cues measured by functional magnetic resonance imaging (fMRI) are influenced by physical activity. Seven databases were searched up to February 2023 for human studies evaluating visual food-cue reactivity using fMRI alongside an assessment of habitual physical activity or structured exercise exposure. Eight studies (1 exercise training, 4 acute crossover, 3 cross-sectional) were included in a qualitative synthesis. Structured acute and chronic exercise appear to lower food-cue reactivity in several brain regions, including the insula, hippocampus, orbitofrontal cortex (OFC), postcentral gyrus and putamen, particularly when viewing high-energy-density food cues. Exercise, at least acutely, may enhance appeal of low-energy-density food-cues. Cross-sectional studies show higher self-reported physical activity is associated with lower reactivity to food-cues particularly of high-energy-density in the insula, OFC, postcentral gyrus and precuneus. This review shows that physical activity may influence brain food-cue reactivity in motivational, emotional, and reward-related processing regions, possibly indicative of a hedonic appetite-suppressing effect. Conclusions should be drawn cautiously given considerable methodological variability exists across limited evidence.


Assuntos
Sinais (Psicologia) , Alimentos , Humanos , Estudos Transversais , Encéfalo/fisiologia , Imageamento por Ressonância Magnética/métodos , Exercício Físico
16.
Med Sci Sports Exerc ; 55(9): 1548-1554, 2023 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-37093903

RESUMO

INTRODUCTION: This cross-sectional study examined associations of device-measured sedentary time and moderate-to-vigorous physical activity (MVPA) with adipose tissue insulin resistance in people with or at high risk of type 2 diabetes (T2DM). METHOD: Data were combined from six previous experimental studies (within our group) involving patients with T2DM or primary risk factors (median (interquartile range) age, 66.2 (66.0-70.8) yr; body mass index (BMI), 31.1 (28.0-34.4) kg·m -2 ; 62% male; n = 179). Adipose tissue insulin resistance was calculated as the product of fasted circulating insulin and nonesterified fatty acids (ADIPO-IR), whereas sedentary time and MVPA were determined from wrist-worn accelerometery. Generalized linear models examined associations of sedentary time and MVPA with ADIPO-IR with interaction terms added to explore the moderating influence of ethnicity (White European vs South Asian), BMI, age, and sex. RESULTS: In finally adjusted models, sedentary time was positively associated with ADIPO-IR, with every 30 min of sedentary time associated with a 1.80-unit (95% confidence interval, 0.51-3.06; P = 0.006) higher ADIPO-IR. This relationship strengthened as BMI increased ( ß = 3.48 (95% confidence interval, 1.50-5.46), P = 0.005 in the upper BMI tertile (≥33.2 kg·m -2 )). MVPA was unrelated to ADIPO-IR. These results were consistent in sensitivity analyses that excluded participants taking statins and/or metformin ( n = 126) and when separated into the participants with T2DM ( n = 32) and those at high risk ( n = 147). CONCLUSIONS: Sedentary time is positively related to adipose tissue insulin sensitivity in people with or at high risk of T2DM. This relationship strengthens as BMI increases and may help explain established relationships between greater sedentary time, ectopic lipid, and hyperglycemia.


Assuntos
Diabetes Mellitus Tipo 2 , Resistência à Insulina , Humanos , Masculino , Adulto , Idoso , Feminino , Comportamento Sedentário , Estudos Transversais , Tecido Adiposo
17.
Appl Physiol Nutr Metab ; 48(6): 436-444, 2023 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-36867855

RESUMO

Leukocyte cell-derived chemotaxin-2 (LECT2) and fibroblast growth factor 21 (FGF21) are hepatokines that are regulated by energy balance and mediate insulin sensitivity and glycaemic control. This cross-sectional study examined the independent associations of cardiorespiratory fitness (CRF), moderate-to-vigorous intensity physical activity (MVPA), and sedentary time with circulating LECT2 and FGF21. Data were combined from two previous experimental studies in healthy volunteers (n = 141, male = 60%, mean ± SD age = 37 ± 19 years, body mass index (BMI) = 26.1 ± 6.3 kg·m-2). Sedentary time and MVPA were measured via an ActiGraph GT3X + accelerometer, while magnetic resonance imaging quantified liver fat. CRF was assessed using incremental treadmill tests. Generalized-linear models examined the association of CRF, sedentary time, and MVPA with LECT2 and FGF21 while controlling for key demographic and anthropometric variables. Interaction terms explored the moderating influence of age, sex, BMI, and CRF. In the fully adjusted models, each SD increase in CRF was independently associated with a 24% (95% CI: -37% to -9%, P = 0.003) lower plasma LECT2 concentration and 53% lower FGF21 concentration (95% CI: -73% to -22%, P = 0.004). Each SD increase in MVPA was independently associated with 55% higher FGF21 (95% CI: 12% to 114%, P = 0.006), and this relationship was stronger in those with lower BMI and higher levels of CRF. These findings demonstrate that CRF and wider activity behaviours may independently modulate the circulating concentrations of hepatokines and thereby influence inter-organ cross-talk.


Assuntos
Aptidão Cardiorrespiratória , Humanos , Masculino , Adolescente , Adulto Jovem , Adulto , Pessoa de Meia-Idade , Voluntários Saudáveis , Estudos Transversais , Exercício Físico , Leucócitos , Aptidão Física , Peptídeos e Proteínas de Sinalização Intercelular
18.
Med Sci Sports Exerc ; 55(5): 794-802, 2023 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-36729923

RESUMO

INTRODUCTION: South Asians (SAs) have an elevated risk of cardiovascular disease (CVD) compared with White Europeans (WEs). Postprandial endothelial function (flow-mediated dilatation (FMD%)) in SA women and SA men with central obesity has not been investigated. Research in other populations has highlighted that a 1% higher FMD% is associated with a ~13% lower risk of future CVD events. We investigated whether FMD% and lipemia, two markers for CVD risk, were higher in SAs versus WEs, whether walking improved FMD% and lipemia, and if there were ethnic differences in the response. METHODS: Lean premenopausal women (study 1; 12 SA, 12 WE) and men with central obesity (study 2; 15 SA, 15 WE) completed two 2-d trials. On day 1, participants walked for 60 min at 60% of their peak oxygen uptake or rested. On day 2, participants rested and consumed two high-fat meals over 8 h. Repeated ultrasound assessments of endothelial function and venous blood samples for CVD risk markers were taken. RESULTS: Compared with WEs, SAs had lower postprandial FMD% (study 1, -1.32%; study 2, -0.54%) and higher postprandial triacylglycerol concentrations (study 1, 0.31 mmol·L -1 ·h -1 ; study 2, 0.55 mmol·L -1 ·h -1 ). Walking improved postprandial FMD% (study 1, 1.12%; study 2, 0.94%) and resulted in no significant change or small reductions in postprandial triacylglycerol concentrations (study 1, -0.01 mmol·L -1 ·h -1 ; study 2, -0.25 mmol·L -1 ·h -1 ). Exercise-induced changes in FMD% and triacylglycerol were consistent between ethnic groups. CONCLUSIONS: Walking mitigated the adverse postprandial effect of a high-fat diet on FMD% to a similar extent in SA and WE women and men, even with no/small improvements in triacylglycerol. This study highlights the importance of exercise to clinically improve FMD% in SAs and WEs.


Assuntos
Doenças Cardiovasculares , Hiperlipidemias , Masculino , Humanos , Feminino , População Europeia , Obesidade Abdominal , População do Sul da Ásia , Triglicerídeos , Caminhada/fisiologia , Período Pós-Prandial/fisiologia , Estudos Cross-Over , Gorduras na Dieta , População Branca
19.
Gastroenterology ; 164(4): 567-578.e7, 2023 04.
Artigo em Inglês | MEDLINE | ID: mdl-36634826

RESUMO

BACKGROUND & AIMS: The incidence of biopsy-confirmed celiac disease has increased. However, few studies have explored the incidence of celiac autoimmunity based on positive serology results. METHODS: A population-based cohort study assessed testing of tissue transglutaminase antibodies (tTG-IgA) in Alberta from 2012 to 2020. After excluding prevalent cases, incident celiac autoimmunity was defined as the first positive tTG-IgA result between 2015 and 2020. Testing and incidence rates for celiac autoimmunity were calculated per 1000 and 100,000 person-years, respectively. Incidence rate ratios (IRRs) were calculated to identify differences by demographic and regional factors. Average annual percent changes (AAPCs) assessed trends over time. RESULTS: The testing rate of tTG-IgA was 20.2 per 1000 person-years and remained stable from 2012 to 2020 (AAPC, 1.2%; 95% confidence interval [CI], -0.5 to 2.9). Testing was higher in female patients (IRR, 1.66; 95% CI, 1.65-1.66), those living in metropolitan areas (IRR, 1.39; 95% CI, 1.38-1.40), and in areas of lower socioeconomic deprivation (lowest compared to highest IRR, 1.24; 95% CI, 1.23-1.25). Incidence of celiac autoimmunity was 33.8 per 100,000 person-years and increased from 2015 to 2020 (AAPC, 6.2%; 95% CI, 3.1-9.5). Among those with tTG-IgA results ≥10 times the upper limit of normal, the incidence was 12.9 per 100,000 person-years. The incidence of celiac autoimmunity was higher in metropolitan settings (IRR, 1.28; 95% CI, 1.21-1.35) and in the least socioeconomically deprived areas compared to the highest (IRR, 1.22; 95% CI, 1.14-1.32). CONCLUSIONS: Incidence of celiac autoimmunity is high and increasing, despite stable testing rates. Variation in testing patterns may lead to underreporting the incidence of celiac autoimmunity in nonmetropolitan areas and more socioeconomically deprived neighborhoods.


Assuntos
Autoimunidade , Doença Celíaca , Humanos , Feminino , Incidência , Transglutaminases , Estudos de Coortes , Imunoglobulina A , Autoanticorpos , Canadá , Doença Celíaca/diagnóstico , Doença Celíaca/epidemiologia
20.
Scand J Med Sci Sports ; 33(5): 550-568, 2023 May.
Artigo em Inglês | MEDLINE | ID: mdl-36610000

RESUMO

Exercise is recommended for those with, or at risk of nonalcoholic fatty liver disease (NAFLD), owing to beneficial effects on hepatic steatosis and cardiometabolic risk. Whilst exercise training reduces total intrahepatic lipid in people with NAFLD, accumulating evidence indicates that exercise may also modulate hepatic lipid composition. This metabolic influence is important as the profile of saturated (SFA), monounsaturated (MUFA), and polyunsaturated fatty acids (PUFA) dramatically affect the metabolic consequences of hepatic lipid accumulation; with SFA being especially lipotoxic. Relatedly, obesity and NAFLD are associated with hepatic PUFA depletion and elevated SFA. This review summarizes the acute (single bout) and chronic (exercise training) effects of exercise on hepatic lipid composition in rodents (acute studies: n = 3, chronic studies: n = 13) and humans (acute studies: n = 1, chronic studies: n = 3). An increased proportion of hepatic PUFA after acute and chronic exercise is the most consistent finding of this review. Mechanistically, this may relate to an enhanced uptake of adipose-derived PUFA (reflecting habitual diet), particularly in rodents. A relative decrease in the proportion of hepatic MUFA after chronic exercise is also documented repeatedly, particularly in rodent models with elevated hepatic MUFA. This outcome is related to decreased hepatic stearoyl-CoA desaturase-1 activity in some studies. Findings regarding hepatic SFA are less consistent and limited by the absence of metabolic challenge in rodent models. These findings require confirmation in well-controlled interventions in people with NAFLD. These studies will be facilitated by recently validated magnetic resonance spectroscopy techniques, able to precisely quantify hepatic lipid composition in vivo.


Assuntos
Hepatopatia Gordurosa não Alcoólica , Humanos , Ácidos Graxos Monoinsaturados/metabolismo , Ácidos Graxos Insaturados/metabolismo , Obesidade/metabolismo , Exercício Físico , Ácidos Graxos/metabolismo
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