46 research outputs found

    Designing peptide nanoparticles for efficient brain delivery

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    The targeted delivery of therapeutic compounds to the brain is arguably the most significant open problem in drug delivery today. Nanoparticles (NPs) based on peptides and designed using the emerging principles of molecular engineering show enormous promise in overcoming many of the barriers to brain delivery faced by NPs made of more traditional materials. However, shortcomings in our understanding of peptide self-assembly and blood–brain barrier (BBB) transport mechanisms pose significant obstacles to progress in this area. In this review, we discuss recent work in engineering peptide nanocarriers for the delivery of therapeutic compounds to the brain, from synthesis, to self-assembly, to in vivo studies, as well as discussing in detail the biological hurdles that a nanoparticle must overcome to reach the brain

    A Novel Plant-Based Protein Has Similar Effects Compared to Whey Protein on Body Composition, Strength, Power, and Aerobic Performance in Professional and Semi-Professional Futsal Players

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    IntroductionThe effects of dietary protein on body composition and physical performance seemingly depend on the essential amino acid profile of the given protein source, although controversy exists about whether animal protein sources may possess additional anabolic properties to plant-based protein sources. PurposeTo compare the effects of a novel plant-based protein matrix and whey protein supplementation on body composition, strength, power, and endurance performance of trained futsal players. MethodsFifty male futsal players were followed during 8 weeks of supplementation, with 40 completing the study either with plant-based protein (N = 20) or whey protein (N = 20). The following measures were assessed: bone mineral content, lean body mass, and fat mass; muscle thickness of the rectus femoris; total body water; blood glucose, hematocrit, C-reactive protein, aspartate aminotransferase, alanine aminotransferase, creatine kinase, creatinine, and estimated glomerular filtration rate; salivary cortisol; maximal strength and 1-RM testing of the back squat and bench press exercises; muscle power and countermovement jump; VO2max and maximal aerobic speed. Subjects were asked to maintain regular dietary habits and record dietary intake every 4 weeks through 3-day food records. ResultsNo differences in any variable were observed between groups at baseline or pre- to post-intervention. Moreover, no time*group interaction was observed in any of the studied variables, and a time effect was only observed regarding fat mass reduction. ConclusionsSupplementing with either a novel plant-based protein matrix or whey protein did not affect any of the variables assessed in high-level futsal players over 8 wks. These results suggest that whey protein does not possess any unique anabolic properties over and above those of plant-based proteins when equated to an essential amino acid profile in the population studied. Furthermore, when consuming a daily protein intake >1.6 g/kg BW.day(-1), additional protein supplementation does not affect body composition or performance in trained futsal players, regardless of protein type/source

    The effect of acute vs chronic magnesium supplementation on exercise and recovery on resistance exercise, blood pressure and total peripheral resistance on normotensive adults

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    © 2015 Kass and Poeira; licensee BioMed Central. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.Background: Magnesium supplementation has previously shown reductions in blood pressure of up to 12 mmHg. A positive relationship between magnesium supplementation and performance gains in resistance exercise has also been seen. However, no previous studies have investigated loading strategies to optimise response. The aim of this study was to assess the effect of oral magnesium supplementation on resistance exercise and vascular response after intense exercise for an acute and chronic loading strategy on a 2-day repeat protocol. Methods: The study was a randomised, double-blind, cross-over design, placebo controlled 2 day repeat measure protocol (n = 13). Intense exercise (40 km time trial) was followed by bench press at 80% 1RM to exhaustion, with blood pressure and total peripheral resistance (TPR) recorded. 300 mg/d elemental magnesium was supplemented for either a 1 (A) or 4 (Chr) week loading strategy. Food diaries were recorded. Results: Dietary magnesium intake was above the Reference Nutrient Intake (RNI) for all groups. Bench press showed a significant increase of 17.7% (p = 0.031) for A on day 1. On day 2 A showed no decrease in performance whilst Chr showed a 32.1% decrease. On day 2 post-exercise systolic blood pressure (SBP) was significantly lower in both A (p = 0.0.47) and Chr (p = 0.016) groups. Diastolic blood pressure (DBP) showed significant decreases on day 2 solely for A (p = 0.047) with no changes in the Chr. TPR reduced for A on days 1 and 2 (p = 0.031) with Chr showing an increase on day 1 (p = 0.008) and no change on day 2. Conclusion: There was no cumulative effect of Chr supplementation compared to A. A group showed improvement for bench press concurring with previous research which was not seen in Chr. On day 2 A showed a small non-significant increase but not a decrement as expected with Chr showing a decrease. DBP showed reductions in both Chr and A loading, agreeing with previous literature. This is suggestive of a different mechanism for BP reduction than for muscular strength. TPR showed greater reductions with A than Chr, which would not be expected as both interventions had reductions in BP, which is associated with TPR.Peer reviewedFinal Published versio

    Interplay between n-3 and n-6 long-chain polyunsaturated fatty acids and the endocannabinoid system in brain protection and repair.

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    The brain is enriched in arachidonic acid (ARA) and docosahexaenoic acid (DHA), long-chain polyunsaturated fatty acids (LCPUFA) of the n-6 and n-3 series, respectively. Both are essential for optimal brain development and function. Dietary enrichment with DHA and other long-chain n-3 PUFA, such as eicosapentaenoic acid (EPA) have shown beneficial effects on learning and memory, neuroinflammatory processes and synaptic plasticity and neurogenesis. ARA, DHA and EPA are precursors to a diverse repertoire of bioactive lipid mediators, including endocannabinoids. The endocannabinoid system comprises cannabinoid receptors, their endogenous ligands, the endocannabinoids, and their biosynthetic and degradation enzymes. Anandamide (AEA) and 2-archidonoylglycerol (2-AG) are the most widely studied endocannabinoids, and are both derived from phospholipid-bound ARA. The endocannabinoid system also has well established roles in neuroinflammation, synaptic plasticity and neurogenesis, suggesting an overlap in the neuroprotective effects observed with these different classes of lipids. Indeed, growing evidence suggests a complex interplay between n-3 and n-6 LCPUFA and the endocannabinoid system. For example, long-term DHA and EPA supplementation reduces AEA and 2-AG levels, with reciprocal increases in levels of the analogous endocannabinoid-like DHA and EPA-derived molecules. This review summarises current evidence of this interplay and discusses the therapeutic potential for brain protection and repair

    Estimation of percent body fat based on anthropometric measurements in children and adolescents with congenital adrenal hyperplasia due to 21-hydroxylase deficiency

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    Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Background & aim: Congenital adrenal hyperplasia due to 21-hydroxylase deficiency is associated with a high risk for obesity. Anthropometric measures are simple and inexpensive methods to assess body fat. However, the accuracy of alternative methods in these patients is unknown. This study aim to develop and evaluate the accuracy of predictive anthropometric equations in the estimation of percent body fat in individuals with congenital adrenal hyperplasia due to 21-hydroxylase deficiency. Methods: A total of 31 female and 22 male patients, aged 7-20 years, were evaluated. Dual-energy X-ray absorptiometry was used as the reference method for body fat, and anthropometric measurements were performed. Results: Three new predictive equations showed similar results: Equation (1) (R-2 = 0.85; SEE = 2.89%), Equation (2) (R-2 = 0.86; SEE = 2.82%), and Equation (3) (R-2 = 0.86; SEE = 2.81%). Internal cross-validation procedures showed a high R-2 (range, 0.84-0.85) and low SEE (<3%). The limits of agreement ranged from -5.6% to 5.6% and no trend was observed. Conclusion: In children and adolescents with congenital adrenal hyperplasia due to 21-hydroxylase deficiency, three new predictive equations were validated for the estimation of percent body fat, with dual-energy X-ray absorptiometry as the reference method. (C) 2012 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.3214550Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Ministry of Education, Brazil [BEX 2018/10-1]Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Ministry of Education, Brazil [BEX 2018/10-1

    Lack of agreement of in vivo raw bioimpedance measurements obtained from two single and multi-frequency bioelectrical impedance devices

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    Background: It is important for highly active individuals to accurately assess their hydration level. Bioelectrical impedance (BIA) can potentially meet these needs but its validity in active individuals is not well established. Methods: We compared whole-body bioimpedance measurements obtained from multi-frequency bioelectrical impedance spectroscopy (BIS, Xitron 4200) at a 50 kHz frequency with those determined by a phase-sensitive single-frequency device (SF-BIA, BIA-101, RJL/Akern Systems) in two populations: active adults and elite athletes. Results: One hundred twenty-six participants, including active males involved in recreational sports (N = 25, 20–39 yr) and elite athletes (females: N = 26, 18–35 yr; males: N = 75, 18–38 yr) participated in this study. Reactance (Xc), Resistance (R), Impedance (Z), and phase angle (PhA) were obtained by BIS and SF-BIA. Small but significant differences (R: −9.91 ± 15.09 Ω; Xc: −0.97 ± 2.56 Ω; Z: −9.96 ± 15.18 Ω; PhA: 0.12 ± 0.2°) were observed between the bioimpedance equipment in all measured variables (p &lt; 0.05) though differences were within the devices’ technical error of measurements. Device-specific values were highly (p &lt; 0.0001) correlated [R2 ranged from 0.881 (Xc) to 0.833 (R)], but slopes and intercepts were different (p &lt; 0.0001) from 1 and 0, respectively. Relatively large limits of agreement were observed for R (−40 to 21 Ω), Xc (−6 to 4 Ω), PhA (−0.4 to 0.5°), and impedance (−40 to 20 Ω). Conclusion:: Bioimpedance measurements from the current single- and multi-frequency devices should not be used interchangeably. The of lack of agreement between devices was observed in determining individual values of R, Xc, Z and PhA of highly active populations possibly due to methodological and biological factors. © 2018, Springer Nature Limited

    Is bioelectrical impedance spectroscopy accurate in estimating total body water and its compartments in elite athletes?

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    Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Background: Bioelectrical impedance spectroscopy (BIS) provides an affordable assessment of the body's various water compartments: total body water (TBW), extracellular water (ECW) and intracellular water (ICW). However, little is known of its validity in athletes. Aim: To validate TBW, ECW and ICW by BIS in elite male and female Portuguese athletes using dilution techniques (i.e. deuterium and bromide dilution) as criterion methods. Subjects and methods: Sixty-two athletes (18.5 +/- 4.1 years) had TBW, ECW and ICW assessed by BIS during their respective pre-season. Results: BIS significantly under-estimated TBW by 1.0 +/- 1.7 kg and ICW by 0.9 +/- 1.9 kg in relation to the criterion methods, with no differences observed for ECW. The values for the concordance correlation coefficient were 0.98 for TBW and ECW and 0.95 for ICW. Bland-Altman analyses revealed no bias for the various water compartments, with the 95% confidence intervals ranging from -4.8 to 2.6 kg for TBW, -1.5 to 1.6 kg for ECW and -4.5 to 2.7 kg for ICW. Conclusions: Overall, these findings demonstrate the validity of BIS as a valid tool in the assessment of TBW and its compartments in both male and female athletes.402152156Portuguese Foundation for Science and Technology [PTDC/DES/69495/2006, PTDC/DES/098963/2008]Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Portuguese Foundation for Science and Technology [PTDC/DES/69495/2006, PTDC/DES/098963/2008]CAPES [BEX 2018/10-1

    Body composition in taller individuals using DXA: A validation study for athletic and non-athletic populations

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    Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Dual energy X-ray absorptiometry (DXA) cannot be used to evaluate participants taller than the scan area. We aimed to analyse the accuracy of bone mineral content, fat mass, and lean mass assessed with DXA whole-body scan and from the sum of two scans (head and trunk plus limbs). Participants were 31 athletes (13 males and 18 females) and 65 non-athletes (34 males and 31 females), that fit within the DXA scan area. Three scans were performed using a Hologic Explorer-W fan-beam densitometer: a whole-body scan used as the reference; a head scan; and a trunk and limbs scan. The sum of the head scan and the trunk and limbs scan was used as the alternative procedure. Multiple regression and agreement analysis were performed. Non-significant differences between methods were observed for fat mass (0.06kg) and lean mass (0.07kg) while bone mineral content from the alternative procedure differed from the reference scan (0.009kg). The alternative procedure explained>99% of the variance in the reference scan and low limits of agreement were observed. Precision analysis indicated low pure errors and the higher coefficients of variation were found for fat mass (whole-body: 3.70%; subtotal: 4.05%). The method proposed is a valid and simple solution to be used in individuals taller than the DXA scan area, including athletes engaged in sports recognised for including very tall competitors.314405413Portuguese Foundation for Science and Technology [PTDC/DES/098963/2008, SFRH/BD/46503/2008]Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Portuguese Foundation for Science and Technology [PTDC/DES/098963/2008, SFRH/BD/46503/2008]CAPES [BEX 3014/10-0, BEX 2018/10-1, BEX 8827/11-7

    Total body water and its compartments are not affected by ingesting a moderate dose of caffeine in healthy young adult males

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    Acute and chronic caffeine intakes have no impact on hydration status (R.J. Maughan and J. Griffin, J. Hum. Nutr. Diet. 16(6): 411-420, 2003), although no research has been conducted to analyze the effects using dilution techniques on total-body water (TBW) and its compartments. Therefore, the aim of this study was to investigate the effects of a moderate dose of caffeine on TBW, extracellular water (ECW), and intracellular water (ICW) during a 4-day period in active males. Thirty men, nonsmokers and low caffeine users ( 0.05). TBW, ECW, and ICW were unrelated to fat-free mass, water ingestion, and PA (p > 0.05). These findings indicate that a moderate caffeine dose, equivalent to approximately 5 espresso cups of coffee or 7 servings of tea, does not alter TBW and fluid distribution in healthy men, regardless of body composition, PA, or daily water ingestion.386626632Portuguese Institute of Hydration and Healt
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