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1.
Philos Trans A Math Phys Eng Sci ; 381(2242): 20210238, 2023 Feb 20.
Artículo en Inglés | MEDLINE | ID: mdl-36587819

RESUMEN

The self-organization of structures in a tokamak plasma as it undergoes an [Formula: see text]-mode transition shows properties similar to simpler shear flow configurations. We will describe recent dynamical studies of plasma shear flows, including the idea of tracking the edge of chaos that separates two bistable states, computing the nonlinear minimal seed that can lead to turbulence, finding the attractor solution on the edge and seeing how starting from this solution we can understand the stability of relative period orbits that permeate the turbulent basin of attraction. We present a modus operandi developed for these simple configurations that can be adapted to understand the [Formula: see text]-mode transition. This article is part of a discussion meeting issue 'H-mode transition and pedestal studies in fusion plasmas'.

2.
Plast Reconstr Surg ; 149(2): 404-411, 2022 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-35077415

RESUMEN

BACKGROUND: Activation of platelets in platelet-rich plasma may improve growth factor release, thus enhancing regenerative properties. The authors investigated whether different methods of platelet-rich plasma activation affected growth factor release kinetics over time. METHODS: Platelet-rich plasma from 20 healthy volunteers was processed by six different methods: (1) control (nonactivated); (2) activation with calcium chloride; (3) activation with calcium chloride and ethanol; (4) activation with calcium chloride and ethanol at 4°C; (5) activation with calcium chloride and ethanol with vitamin C; (6) activation with calcium chloride and ethanol with vitamin C at 4°C. Concentration of secreted vascular endothelial growth factor (VEGF), platelet-derived growth factor (PDGF), and insulin-like growth factor over 24 hours was measured by immunoassay. RESULTS: Calcium chloride-activated platelet-rich plasma produced significantly more insulin-like growth factor at 1 hour compared to cold and vitamin C platelet-rich plasma, and calcium chloride plus ethanol produced significantly more at 24 hours compared to vitamin C platelet-rich plasma. The addition of vitamin C reduced release of PDGF over time. Activation with calcium chloride and ethanol with or without cold temperature produced a gradual PDGF release as opposed to calcium chloride alone, which caused higher PDGF within 4 hours. There were no significant differences between groups for VEGF, although calcium chloride and cooled platelet-rich plasma approached significance for producing more than vitamin C platelet-rich plasma. CONCLUSIONS: Activation of platelet-rich plasma does not significantly improve growth factor secretion, which is made worse by the addition of vitamin C, a platelet inhibitor. Ethanol does not negatively impact growth factor production and may offer a more gradual release. CLINICAL RELEVANCE STATEMENT: These findings will help guide platelet-rich plasma preparation methods where therapeutic growth factors are used. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, V.


Asunto(s)
Activación Plaquetaria/fisiología , Factor de Crecimiento Derivado de Plaquetas/metabolismo , Plasma Rico en Plaquetas/metabolismo , Somatomedinas/metabolismo , Adolescente , Adulto , Ácido Ascórbico/farmacología , Cloruro de Calcio/farmacología , Etanol/farmacología , Femenino , Voluntarios Sanos , Humanos , Masculino , Persona de Mediana Edad , Adulto Joven
3.
Exp Physiol ; 106(5): 1208-1223, 2021 05.
Artículo en Inglés | MEDLINE | ID: mdl-33675111

RESUMEN

NEW FINDINGS: What is the central question of this study? What is the relationship between proteins in skeletal muscle and adipose tissue determined at rest and at peak rates of fat oxidation in men and women? What is the main finding and its importance? The resting contents of proteins in skeletal muscle involved in triglyceride hydrolysis and mitochondrial lipid transport were more strongly associated with peak fat oxidation rates than proteins related to lipid transport or hydrolysis in adipose tissue. Although females displayed higher relative rates of fat oxidation than males, this was not explained by the proteins measured in this study, suggesting that other factors determine sex differences in fat metabolism. ABSTRACT: We explored key proteins involved in fat metabolism that might be associated with peak fat oxidation (PFO) and account for sexual dimorphism in fuel metabolism during exercise. Thirty-six healthy adults [15 women; 40 ± 11 years of age; peak oxygen consumption 42.5 ± 9.5 ml (kg body mass)-1  min-1 ; mean ± SD] completed two exercise tests to determine PFO via indirect calorimetry. Resting adipose tissue and/or skeletal muscle biopsies were obtained to determine the adipose tissue protein content of PLIN1, ABHD5 (CGI-58), LIPE (HSL), PNPLA2 (ATGL), ACSL1, CPT1B and oestrogen receptor α (ERα) and the skeletal muscle protein content of FABP 3 (FABPpm), PNPLA2 (ATGL), ACSL1, CTP1B and ESR1 (ERα). Moderate strength correlations were found between PFO [in milligrams per kilogram of fat-free mass (FFM) per minute] and the protein content of PNPLA2 (ATGL) [rs  = 0.41 (0.03-0.68), P < 0.05] and CPT1B [rs  = 0.45 (0.09-0.71), P < 0.05] in skeletal muscle. No other statistically significant bivariate correlations were found consistently. Females had a greater relative PFO than males [7.1 ± 1.9 vs. 4.5 ± 1.3 and 7.3 ± 1.7 vs. 4.8 ± 1.2 mg (kg FFM)-1  min-1 in the adipose tissue (n = 14) and skeletal muscle (n = 12) subgroups, respectively (P < 0.05)]. No statistically significant sex differences were found in the content of these proteins. The regulation of PFO might involve processes relating to intramyocellular triglyceride hydrolysis and mitochondrial fatty acid transport, and adipose tissue is likely to play a more minor role than muscle. Sex differences in fat metabolism are likely to be attributable to factors other than the resting content of proteins in skeletal muscle and adipose tissue relating to triglyceride hydrolysis and fatty acid transport.


Asunto(s)
Músculo Esquelético , Caracteres Sexuales , 1-Acilglicerol-3-Fosfato O-Aciltransferasa/metabolismo , Aciltransferasas , Tejido Adiposo/metabolismo , Adulto , Carnitina O-Palmitoiltransferasa/metabolismo , Ejercicio Físico/fisiología , Femenino , Humanos , Lipasa/metabolismo , Metabolismo de los Lípidos , Masculino , Músculo Esquelético/metabolismo
4.
Int J Sport Nutr Exerc Metab ; 31(3): 227-235, 2021 05 01.
Artículo en Inglés | MEDLINE | ID: mdl-33588373

RESUMEN

This study explored lifestyle and biological determinants of peak fat oxidation (PFO) during cycle ergometry, using duplicate measures to account for day-to-day variation. Seventy-three healthy adults (age range: 19-63 years; peak oxygen consumption [V˙O2peak]: 42.4 [10.1] ml·kg BM-1·min-1; n = 32 women]) completed trials 7-28 days apart that assessed resting metabolic rate, a resting venous blood sample, and PFO by indirect calorimetry during an incremental cycling test. Habitual physical activity (combined heart rate accelerometer) and dietary intake (weighed record) were assessed before the first trial. Body composition was assessed 2-7 days after the second identical trial by dual-energy X-ray absorptiometry scan. Multiple linear regressions were performed to identify determinants of PFO (mean of two cycle tests). A total variance of 79% in absolute PFO (g·min-1) was explained with positive coefficients for V˙O2peak (strongest predictor), FATmax (i.e the % of V˙O2peak that PFO occurred at), and resting fat oxidation rate (g·min-1), and negative coefficients for body fat mass (kg) and habitual physical activity level. When expressed relative to fat-free mass, 64% of variance in PFO was explained: positive coefficients for FATmax (strongest predictor), V˙O2peak, and resting fat oxidation rate, and negative coefficients for male sex and fat mass. This duplicate design revealed that biological and lifestyle factors explain a large proportion of variance in PFO during incremental cycling. After accounting for day-to-day variation in PFO, V˙O2peak and FATmax were strong and consistent predictors of PFO.


Asunto(s)
Ciclismo/psicología , Grasas/metabolismo , Adulto , Pruebas Respiratorias , Calorimetría Indirecta , Estudios Transversales , Registros de Dieta , Ejercicio Físico , Prueba de Esfuerzo , Femenino , Humanos , Modelos Lineales , Lípidos , Masculino , Persona de Mediana Edad , Oxidación-Reducción , Factores Sexuales , Adulto Joven
5.
Adipocyte ; 10(1): 80-90, 2021 12.
Artículo en Inglés | MEDLINE | ID: mdl-33525977

RESUMEN

Stem cells could form the basis of a novel, autologous treatment for chronic wounds like diabetic foot ulcers. Fat grafts contain adipose-derived stem cells (ADSC) but low survival of cells within the grafts is a major limitation. Platelet-rich plasma (PRP) may increase graft survival. This review examines the histology from animal studies on fat grafting, ADSC and PRP in wound healing. A literature review of major electronic databases was undertaken, and narrative synthesis performed. Data from 30 animal studies were included. ADSC increase angiogenesis over 14 days and often clinically accelerated wound healing. ADSC had a greater effect in animals with impaired wound healing (e.g. diabetes). Activated PRP increased viability of fat grafts. Despite the high number of studies, the quality is variable which weakens the evidence. It does suggest there is a benefit of ADSC, particularly in impaired wound healing. High-quality evidence in humans is required, to establish its clinical usefulness.


Asunto(s)
Tejido Adiposo/trasplante , Plasma Rico en Plaquetas/fisiología , Cicatrización de Heridas/fisiología , Adipocitos/metabolismo , Adipocitos/trasplante , Tejido Adiposo/metabolismo , Animales , Proliferación Celular/fisiología , Humanos , Modelos Animales , Plasma Rico en Plaquetas/metabolismo , Trasplante de Células Madre/métodos , Células Madre , Trasplante/métodos , Trasplantes/metabolismo
6.
Int Wound J ; 18(4): 448-456, 2021 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-33476481

RESUMEN

Chronic wounds are a considerable health burden with high morbidity and poor rates of healing. Colonisation of chronic wounds by bacteria can be a significant factor in their poor healing rate. These bacteria can develop antibiotic resistance over time and can lead to wound infections, systemic illness, and occasionally amputation. When a large number of micro-organisms colonise wounds, they can lead to biofilm formation, which are self-perpetuating colonies of bacteria closed within an extracellular matrix, which are poorly penetrated by antibiotics. Platelet-rich plasma (PRP) is an autologous blood product rich in growth factors and cytokines that are involved in an inflammatory response. PRP can be injected or applied to a wound as a topical gel, and there is some interest regarding its antimicrobial properties and whether this can improve wound healing. This study aimed to evaluate the in vitro bacteriostatic effect of PRP. PRP was collected from healthy volunteers and processed into two preparations: activated PRP-activated with calcium chloride and ethanol; inactivated PRP. The activity of each preparation against Staphylococcus aureus and Staphylococcus epidermis was evaluated against a control by three experiments: bacterial kill assay to assess planktonic bacterial growth; plate colony assay to assess bacterial colony growth; and colony biofilm assay to assess biofilm growth. Compared with control, both preparations of PRP significantly inhibited growth of planktonic S aureus and S epidermis. Activated PRP reduced planktonic bacterial concentration more than inactivated PRP in both bacteria. Both PRP preparations significantly reduced bacterial colony counts for both bacteria when compared with control; however, there was no difference between the two. There was no difference found between biofilm growth in either PRP against control or against the other preparation. This study demonstrates that PRP does have an inhibitory effect on the growth of common wound pathogens. Activation may be an important factor in increasing the antimicrobial effect of PRP. However, we did not find evidence of an effect against more complex bacterial colonies.


Asunto(s)
Plasma Rico en Plaquetas , Infecciones Estafilocócicas , Infección de Heridas , Antibacterianos/farmacología , Humanos , Infecciones Estafilocócicas/tratamiento farmacológico , Cicatrización de Heridas , Infección de Heridas/tratamiento farmacológico
8.
Plast Reconstr Surg Glob Open ; 8(5): e2835, 2020 May.
Artículo en Inglés | MEDLINE | ID: mdl-33154876

RESUMEN

There is a growing interest in the regenerative potential of autologous fat. Adipose-derived stem cells, within the stromal vascular fraction of lipoaspirate samples, demonstrate anti-inflammatory, immunomodulatory, and angiogenic properties. This systematic review aimed to determine the efficacy and safety of autologous fat therapies for wound healing, with an evaluation of the quality of evidence provided by the literature. METHODS: Following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, we searched Ovid Medline, Embase, and Cochrane Library databases from inception to November 2018. We included all human studies where wounds were treated with lipotransfer, cell-assisted lipotransfer, stromal vascular fraction products, or isolated adipose-derived stem cells. Study screening and data extraction were performed by 2 authors. The quality of evidence was evaluated using the GRADE approach. RESULTS: The search strategy returned 5027 citations. From these, 10 observational case series were included in the qualitative synthesis; there were no randomized controlled trials. Patient characteristics, wound etiology, and intervention type differed markedly between studies, precluding formal meta-analysis. Autologous fat grafting was associated with satisfactory wound healing in all studies with low complication rates. However, the quality of evidence was consistently very low. CONCLUSIONS: Autologous fat grafting is an emerging therapeutic option for challenging wounds, although there is insufficient evidence to conclusively demonstrate its effectiveness and adverse event profile. Based on the literature to date, it is unclear whether one type of autologous fat therapy is superior. Well-designed, blinded, prospective randomized controlled trials with adequate methodologic details and objective outcome measure reporting are essential. PROSPERO ID: CRD42017081499.

9.
Plast Reconstr Surg Glob Open ; 8(7): e2832, 2020 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-32802632

RESUMEN

Fasciectomy remains the mainstay of surgical treatment for Dupuytren's disease at many units worldwide, particularly in cases of recurrence after aponeurotomy or enzymatic fasciotomy. In some series, this has been reported as high as 48% in 3 years. The lead author has since abandoned the use of collagenase altogether. In this innovation article, we describe simple maneuvers to aid the planning and dissection of a Dupuytren's fasciectomy. We describe techniques to enable efficient dissection of the cord and minimize problems when designing skin flaps. We also highlight technical points in revision cases.

10.
Int Wound J ; 17(6): 1578-1594, 2020 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-32633854

RESUMEN

Chronic, nonhealing diabetic foot ulcers (DFU) are increasing in prevalence and are often unresponsive to conventional therapy. Adipose tissue, containing adipose-derived stem cells, and platelet rich plasma (PRP) are regenerative therapies rich in growth factors which may provide a solution to chronic wound healing. This study aimed to assess the feasibility of conducting a definitive randomised controlled trial (RCT) to investigate the efficacy of these therapies for the treatment of DFU. This was a single centre, feasibility, three-arm, parallel group RCT. Eligible DFU patients were randomised on a 1:1:1 basis to three intervention arms: control (podiatry); fat grafting; fat grafting with PRP. The intervention was delivered once and patients were followed-up for 12 weeks. The primary objective was to assess measures of trial feasibility. Clinical outcomes and health-related quality of life (HRQoL) were also evaluated. Three hundred and thirty four patients were screened and 32 patients (9.6%) were deemed eligible with 18 enrolled in the trial (6 per arm) over 17 months. All participants completed the trial with no withdrawals or crossover. Participant engagement was high with most HRQoL questionnaires returned and only 4.8% follow-up appointments missed. There were five adverse events (AEs) related to the trial with no serious AEs. Five (28%) of the wounds healed. There was no difference between any of the groups in terms of clinical outcomes. This feasibility study demonstrated that a multi-centre RCT is safe and feasible with excellent patient engagement. We have highlighted crucial information regarding methodology and recruitment, which will guide future trial design. Registration number: NCT03085550 clinicaltrials.gov. Registered 01/03/2017.


Asunto(s)
Tejido Adiposo/trasplante , Diabetes Mellitus , Pie Diabético , Plasma Rico en Plaquetas , Adulto , Anciano , Pie Diabético/terapia , Estudios de Factibilidad , Femenino , Humanos , Masculino , Persona de Mediana Edad
11.
Eur J Appl Physiol ; 120(8): 1745-1759, 2020 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-32488584

RESUMEN

PURPOSE: Prior studies exploring the reliability of peak fat oxidation (PFO) and the intensity that elicits PFO (FATMAX) are often limited by small samples. This study characterised the reliability of PFO and FATMAX in a large cohort of healthy men and women. METHODS: Ninety-nine adults [49 women; age: 35 (11) years; [Formula: see text]O2peak: 42.2 (10.3) mL·kg BM-1·min-1; mean (SD)] completed two identical exercise tests (7-28 days apart) to determine PFO (g·min-1) and FATMAX (%[Formula: see text]O2peak) by indirect calorimetry. Systematic bias and the absolute and relative reliability of PFO and FATMAX were explored in the whole sample and sub-categories of: cardiorespiratory fitness, biological sex, objectively measured physical activity levels, fat mass index (derived by dual-energy X-ray absorptiometry) and menstrual cycle status. RESULTS: No systematic bias in PFO or FATMAX was found between exercise tests in the entire sample (- 0.01 g·min-1 and 0%[Formula: see text]O2peak, respectively; p > 0.05). Absolute reliability was poor [within-subject coefficient of variation: 21% and 26%; typical errors: ± 0.06 g·min-1 and × / ÷ 1.26%[Formula: see text]O2peak; 95% limits of agreement: ± 0.17 g·min-1 and × / ÷ 1.90%[Formula: see text]O2peak, respectively), despite high (r = 0.75) and moderate (r = 0.45) relative reliability for PFO and FATMAX, respectively. These findings were consistent across all sub-groups. CONCLUSION: Repeated assessments are required to more accurately determine PFO and FATMAX.


Asunto(s)
Metabolismo de los Lípidos , Consumo de Oxígeno , Oxígeno/metabolismo , Tejido Adiposo/metabolismo , Adiposidad , Adolescente , Adulto , Anciano , Análisis de Varianza , Sesgo , Calorimetría/métodos , Calorimetría/normas , Capacidad Cardiovascular , Interpretación Estadística de Datos , Prueba de Esfuerzo , Femenino , Humanos , Masculino , Persona de Mediana Edad , Oxidación-Reducción , Reproducibilidad de los Resultados
12.
Eur J Nutr ; 59(6): 2449-2462, 2020 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-31531707

RESUMEN

PURPOSE: To examine whether calcium type and co-ingestion with protein alter gut hormone availability. METHODS: Healthy adults aged 26 ± 7 years (mean ± SD) completed three randomized, double-blind, crossover studies. In all studies, arterialized blood was sampled postprandially over 120 min to determine GLP-1, GIP and PYY responses, alongside appetite ratings, energy expenditure and blood pressure. In study 1 (n = 20), three treatments matched for total calcium content (1058 mg) were compared: calcium citrate (CALCITR); milk minerals rich in calcium (MILK MINERALS); and milk minerals rich in calcium plus co-ingestion of 50 g whey protein hydrolysate (MILK MINERALS + PROTEIN). In study 2 (n = 6), 50 g whey protein hydrolysate (PROTEIN) was compared to MILK MINERALS + PROTEIN. In study 3 (n = 6), MILK MINERALS was compared to the vehicle of ingestion (water plus sucralose; CONTROL). RESULTS: MILK MINERALS + PROTEIN increased GLP-1 incremental area under the curve (iAUC) by ~ ninefold (43.7 ± 11.1 pmol L-1 120 min; p < 0.001) versus both CALCITR and MILK MINERALS, with no difference detected between CALCITR (6.6 ± 3.7 pmol L-1 120 min) and MILK MINERALS (5.3 ± 3.5 pmol L-1 120 min; p > 0.999). MILK MINERALS + PROTEIN produced a GLP-1 iAUC ~ 25% greater than PROTEIN (p = 0.024; mean difference: 9.1 ± 6.9 pmol L-1 120 min), whereas the difference between MILK MINERALS versus CONTROL was small and non-significant (p = 0.098; mean difference: 4.2 ± 5.1 pmol L-1 120 min). CONCLUSIONS: When ingested alone, milk minerals rich in calcium do not increase GLP-1 secretion compared to calcium citrate. Co-ingesting high-dose whey protein hydrolysate with milk minerals rich in calcium increases postprandial GLP-1 concentrations to some of the highest physiological levels ever reported. Registered at ClinicalTrials.gov: NCT03232034, NCT03370484, NCT03370497.


Asunto(s)
Calcio/farmacología , Péptido 1 Similar al Glucagón/metabolismo , Leche/química , Hidrolisados de Proteína/química , Hidrolisados de Proteína/farmacología , Proteína de Suero de Leche/química , Adulto , Animales , Estudios Cruzados , Método Doble Ciego , Ingestión de Alimentos , Humanos , Minerales/farmacología , Periodo Posprandial , Adulto Joven
13.
Eur J Sport Sci ; 20(4): 452-460, 2020 May.
Artículo en Inglés | MEDLINE | ID: mdl-31397212

RESUMEN

Exploring individual responses to exercise training is a growing area of interest. Understanding reasons behind true observed inter-individual responses may help personalise exercise training to maximise the benefits received. While numerous factors have been explored, an often underappreciated consideration in the sport and exercise science field is the influence intra-individual variation, both in a single measurement and in response to an intervention, may have on training outcomes. Several study designs and statistical approaches are available to incorporate intra-individual variation into interventions and accordingly provide information on whether 'true' inter-individual responses are present or if they are an artefact of intra-individual variation. However, such approaches are sparingly applied. Moreover, intra-individual variation may also be important when true inter-individual response differences are present. In this perspective piece, the concept of intra-individual variation is described before briefly summarising study designs and statistical practices to account for intra-individual variation. We then outline two examples of physiological practices (stratified randomisation and prescribing exercise programmes upon training parameters) to demonstrate why sport and exercise scientists should acknowledge intra-individual variation prior to the implementation of an intervention, which potentially offers an additional explanation behind observed true inter-individual responses to training. Repeated testing pre-implementation of exercise training would conceptually provide more confident estimates of training parameters, which if utilised in a study design will help attenuate biases that may dictate inter-individual differences. Moreover, the incorporation of intra-individual differences will facilitate insights into alternative factors that may predict and/or explain true observed individual responses to an exercise training programme.


Asunto(s)
Adaptación Fisiológica , Variación Biológica Individual , Ejercicio Físico , Proyectos de Investigación , Frecuencia Cardíaca , Humanos , Consumo de Oxígeno , Reproducibilidad de los Resultados
14.
J Clin Endocrinol Metab ; 105(3)2020 03 01.
Artículo en Inglés | MEDLINE | ID: mdl-31628477

RESUMEN

CONTEXT: Pre-exercise nutrient availability alters acute metabolic responses to exercise, which could modulate training responsiveness. OBJECTIVE: To assess acute and chronic effects of exercise performed before versus after nutrient ingestion on whole-body and intramuscular lipid utilization and postprandial glucose metabolism. DESIGN: (1) Acute, randomized, crossover design (Acute Study); (2) 6-week, randomized, controlled design (Training Study). SETTING: General community. PARTICIPANTS: Men with overweight/obesity (mean ± standard deviation, body mass index: 30.2 ± 3.5 kg⋅m-2 for Acute Study, 30.9 ± 4.5 kg⋅m-2 for Training Study). INTERVENTIONS: Moderate-intensity cycling performed before versus after mixed-macronutrient breakfast (Acute Study) or carbohydrate (Training Study) ingestion. RESULTS: Acute Study-exercise before versus after breakfast consumption increased net intramuscular lipid utilization in type I (net change: -3.44 ± 2.63% versus 1.44 ± 4.18% area lipid staining, P < 0.01) and type II fibers (-1.89 ± 2.48% versus 1.83 ± 1.92% area lipid staining, P < 0.05). Training Study-postprandial glycemia was not differentially affected by 6 weeks of exercise training performed before versus after carbohydrate intake (P > 0.05). However, postprandial insulinemia was reduced with exercise training performed before but not after carbohydrate ingestion (P = 0.03). This resulted in increased oral glucose insulin sensitivity (25 ± 38 vs -21 ± 32 mL⋅min-1⋅m-2; P = 0.01), associated with increased lipid utilization during exercise (r = 0.50, P = 0.02). Regular exercise before nutrient provision also augmented remodeling of skeletal muscle phospholipids and protein content of the glucose transport protein GLUT4 (P < 0.05). CONCLUSIONS: Experiments investigating exercise training and metabolic health should consider nutrient-exercise timing, and exercise performed before versus after nutrient intake (ie, in the fasted state) may exert beneficial effects on lipid utilization and reduce postprandial insulinemia.


Asunto(s)
Terapia por Ejercicio/métodos , Resistencia a la Insulina , Metabolismo de los Lípidos , Síndrome Metabólico/prevención & control , Obesidad/terapia , Sobrepeso/terapia , Adulto , Estudios de Casos y Controles , Ingestión de Energía , Metabolismo Energético , Estudios de Seguimiento , Humanos , Lípidos/análisis , Masculino , Síndrome Metabólico/epidemiología , Nutrientes , Obesidad/fisiopatología , Sobrepeso/fisiopatología , Reino Unido/epidemiología
15.
Int J Obes (Lond) ; 43(6): 1135-1146, 2019 06.
Artículo en Inglés | MEDLINE | ID: mdl-30482934

RESUMEN

BACKGROUND AND OBJECTIVES: Previous studies have documented that high rates of delay discounting are associated with obesity. However, studies utilizing monetary reward experiments typically report no associations, as opposed to positive associations apparent in studies utilising food-reward experiments. Our objective was to investigate the reasons behind the mixed evidence from a methodological perspective using systematic review and meta-analytic methodologies. METHODS: Seven databases (EMBASE, MEDLINE, PsycINFO, Scopus, Web of Science, Econlit and IBSS) were systematically searched. Logistic meta-regression was applied to identify the determinants of a significant association and risk of bias was assessed using a modified form of the Newcastle Ottawa cohort scale. RESULTS: A total of 59 studies were identified, among which 29 studies (49.2%) found a significant positive association and 29 (49.2%) reported no association. A higher proportion of significant and positive associations was reported in those studies utilizing 'best-practice' methods (i.e. appropriate measurement models) to estimate monetary delay discounting (15/27; 55.6%) and incentive-compatible experiments (10/16; 62.5%) than those using non-'best-practice' methods (14/34; 41.2%) and hypothetical experiments (19/43; 44.2%). All five studies utilizing both 'best-practice' methods and incentive-compatible experiments generated a positive and significant relationship. Results from a logistic meta-regression also suggested that studies employing incentive-compatible experiments (OR: 4.38, 95% CI = 1.05-18.33, p value: 0.04), 'best-practice' methods (OR: 4.40, 95% CI = 0.88-22.99, p value: 0.07), parametric methods (OR: 3.36, 95% CI = 0.83-13.57, p value: 0.04), those conducted in children/adolescent populations (OR: 3.90, 95% CI = 0.85-17.88, p value: 0.08), and those with larger sample size (OR: 1.91, 95% CI = 1.15-3.18, p value: 0.01) tended to show positive and significant associations between delay discounting and obesity. CONCLUSIONS: This review suggests that the mixed evidence to date is a result of methodological heterogeneity, and that future studies should utilise 'best practice' methods.


Asunto(s)
Descuento por Demora , Alimentos , Donaciones , Conductas Relacionadas con la Salud/fisiología , Obesidad/psicología , Recompensa , Descuento por Demora/fisiología , Humanos , Motivación , Obesidad/fisiopatología , Obesidad/prevención & control
16.
Int Wound J ; 16(1): 275-285, 2019 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-30460739

RESUMEN

Fat grafting is becoming a common procedure in regenerative medicine because of its high content of growth factors and adipose derived stem cells (ADSCs) and the ease of harvest, safety, and low cost. The high concentration of ADSCs found in fat has the potential to differentiate into a wide range of wound-healing cells including fibroblasts and keratinocytes as well as demonstrating proangiogenic qualities. This suggests that fat could play an important role in wound healing. However retention rates of fat grafts are highly variable due in part to inconsistent vascularisation of the transplanted fat. Furthermore, conditions such as diabetes, which have a high prevalence of chronic wounds, reduce the potency and regenerative potential of ADSCs. Platelet-rich plasma (PRP) is an autologous blood product rich in growth factors, cell adhesion molecules, and cytokines. It has been hypothesised that PRP may have a positive effect on the survival and retention of fat grafts because of improved proliferation and differentiations of ADSCs, reduced inflammation, and improved vascularisation. There is also increasing interest in a possible synergistic effect that PRP may have on the healing potential of fat, although the evidence for this is very limited. In this review, we evaluate the evidence in both in vitro and animal studies on the mechanistic relationship between fat and PRP and how this translates to a benefit in wound healing. We also discuss future directions for both research and clinical practice on how to enhance the regenerative potential of the combination of PRP and fat.


Asunto(s)
Tejido Adiposo/trasplante , Proliferación Celular/fisiología , Péptidos y Proteínas de Señalización Intercelular/uso terapéutico , Procedimientos de Cirugía Plástica/métodos , Plasma Rico en Plaquetas/fisiología , Cicatrización de Heridas/fisiología , Heridas y Lesiones/terapia , Adulto , Anciano , Femenino , Humanos , Masculino , Persona de Mediana Edad
17.
Syst Rev ; 7(1): 99, 2018 07 18.
Artículo en Inglés | MEDLINE | ID: mdl-30021622

RESUMEN

BACKGROUND: Autologous fat grafting is an emerging therapeutic option for cutaneous wounds. The regenerative potential of autologous fat relates to the presence of adipose-derived stem cells (ADSCs) within the stromal vascular fraction (SVF). ADSCs are capable of differentiating into fibroblasts and keratinocytes, as well as secreting soluble mediators with angiogenic and anti-inflammatory properties. However, to date, there has been no comprehensive assessment of the wound healing literature in humans. This systematic review aims to critically evaluate the efficacy and safety of autologous fat grafting in acute and chronic cutaneous wounds with an appraisal of the quality of evidence available. METHODS: Following PRISMA guidelines, MEDLINE, Embase and Cochrane Library databases will be searched from inception to December 2017. All primary clinical studies in which wounds are treated with lipotransfer, cell-assisted lipotransfer (CAL), SVF products or isolated ADSCs will be eligible for inclusion. Study screening and data extraction will be conducted by two authors in duplicate. Our primary outcome measure will be the proportion of completely healed wounds at 12 weeks. Secondary outcome measures will include the proportion of partially healed wounds at 12 weeks; the mean wound surface area reduction at 12 weeks; the mean time to wound healing; and adverse event rates. The quality of evidence for each summary outcome measure will be assessed using the GRADE approach. DISCUSSION: In light of the growing popularity of autologous fat grafting for wound healing, a systematic appraisal of the available evidence is timely. If autologous fat grafting is associated with a positive treatment effect, we will compare these outcomes to those achieved using alternative wound management strategies. This review also aims to determine if one or more autologous fat grafting techniques are superior and whether this varies according to patient- and wound-specific factors. We anticipate that these results will guide future research and inform clinical practice. SYSTEMATIC REVIEW REGISTRATION: PROSPERO CRD42017081499.


Asunto(s)
Tejido Adiposo/trasplante , Trasplante Autólogo , Cicatrización de Heridas , Enfoque GRADE , Humanos , Resultado del Tratamiento
18.
Appl Physiol Nutr Metab ; 43(12): 1288-1297, 2018 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-29852078

RESUMEN

The maximal capacity to utilise fat (peak fat oxidation, PFO) may have implications for health and ultra-endurance performance and is commonly determined by incremental exercise tests employing 3-min stages. However, 3-min stages may be insufficient to attain steady-state gas kinetics, compromising test validity. We assessed whether 4-min stages produce steady-state gas exchange and reliable PFO estimates in adults with peak oxygen consumption < 40 mL·kg-1·min-1. Fifteen participants (9 females) completed a graded test to determine PFO and the intensity at which this occurred (FATMAX). Three short continuous exercise sessions (SCE) were then completed in a randomised order, involving completion of the graded test to the stage (i) preceding, (ii) equal to (SCEequal), or (iii) after the stage at which PFO was previously attained, whereupon participants then continued to cycle for 10 min at that respective intensity. Expired gases were sampled at minutes 3-4, 5-6, 7-8, and 9-10. Individual data showed steady-state gas exchange was achieved within 4 min during SCEequal. Mean fat oxidation rates were not different across time within SCEequal nor compared with the graded test at FATMAX (both p > 0.05). However, the graded test displayed poor surrogate validity (SCEequal, minutes 3-4 vs. 5-6, 7-8, and 9-10) and day-to-day reliability (minutes 3-4, SCEequal vs. graded test) to determine PFO, as evident by correlations (range: 0.47-0.83) and typical errors and 95% limits of agreement (ranges: 0.03-0.05 and ±0.09-0.15 g·min-1, respectively). In conclusion, intraindividual variation in PFO is substantial despite 4-min stages establishing steady-state gas exchange in individuals with low fitness. Individual assessment of PFO may require multiple assessments.


Asunto(s)
Capacidad Cardiovascular/fisiología , Metabolismo Energético/fisiología , Metabolismo de los Lípidos/fisiología , Adulto , Estudios Cruzados , Prueba de Esfuerzo , Femenino , Humanos , Cinética , Masculino , Oxidación-Reducción , Distribución Aleatoria , Adulto Joven
20.
Int Wound J ; 15(4): 519-526, 2018 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-29745047

RESUMEN

Adipose-derived stem cells found in fat grafts may have significant healing properties. When fat is combined with autologous platelet-rich plasma (PRP), there may be enhanced healing effects due to the pro-angiogenic and anti-inflammatory effects of PRP. This study aimed to evaluate the current evidence on fat grafting in combination with PRP for wound healing to establish the efficacy of this technique. A comprehensive search in the MEDLINE, EMBASE, CENTRAL, Science Citation Index, and Google Scholar databases (to March 2017) was conducted to identify studies on fat grafting and PRP for wound healing. Case series of less than 3 cases and studies only describing harvest technique were excluded. The database identified 571 articles, of which 3 articles that used a combination of fat and PRP for wound healing (1 RCT and 2 case series) were included in this review. A total of 69 wounds in 64 patients were treated with an average wound size of 36.32cm2 . Of these, 67% of wounds achieved complete healing. When reported, the mean time to healing was 7.5 weeks for those who underwent a single treatment. There were no significant complications in any patients. The combination of fat grafting and PRP may achieve adequate wound healing with relatively quick wound healing time compared with standard wound management options. However, evidence is extremely limited, and further studies are required to evaluate its efficacy for wound healing.


Asunto(s)
Tejido Adiposo/trasplante , Procedimientos de Cirugía Plástica/métodos , Plasma Rico en Plaquetas , Repitelización/fisiología , Trasplante de Células Madre/métodos , Cicatrización de Heridas/fisiología , Heridas y Lesiones/terapia , Femenino , Humanos , Masculino
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