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1.
Redox Biol ; 53: 102341, 2022 07.
Artigo em Inglês | MEDLINE | ID: mdl-35623315

RESUMO

The role of mitochondrial ROS in signalling muscle adaptations to exercise training has not been explored in detail. We investigated the effect of supplementation with the mitochondria-targeted antioxidant MitoQ on a) the skeletal muscle mitochondrial and antioxidant gene transcriptional response to acute high-intensity exercise and b) skeletal muscle mitochondrial content and function following exercise training. In a randomised, double-blind, placebo-controlled, parallel design study, 23 untrained men (age: 44 ± 7 years, VO2peak: 39.6 ± 7.9 ml/kg/min) were randomised to receive either MitoQ (20 mg/d) or a placebo for 10 days before completing a bout of high-intensity interval exercise (cycle ergometer, 10 × 60 s at VO2peak workload with 75 s rest). Blood samples and vastus lateralis muscle biopsies were collected before exercise and immediately and 3 h after exercise. Participants then completed high-intensity interval training (HIIT; 3 sessions per week for 3 weeks) and another blood sample and muscle biopsy were collected. There was no effect of acute exercise or MitoQ on systemic (plasma protein carbonyls and reduced glutathione) or skeletal muscle (mtDNA damage and 4-HNE) oxidative stress biomarkers. Acute exercise-induced increases in skeletal muscle peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC1-α) mRNA expression were augmented in the MitoQ group. Despite this, training-induced increases in skeletal muscle mitochondrial content were similar between groups. HIIT-induced increases in VO2peak and 20 km time trial performance were also similar between groups while training-induced increases in peak power achieved during the VO2peak test were augmented in the MitoQ group. These data suggest that training-induced increases in peak power are enhanced following MitoQ supplementation, which may be related to the augmentation of skeletal muscle PGC1α expression following acute exercise. However, these effects do not appear to be related to an effect of MitoQ supplementation on exercise-induced oxidative stress or training-induced mitochondrial biogenesis in skeletal muscle.


Assuntos
Antioxidantes , Exercício Físico , Compostos Organofosforados/farmacologia , Ubiquinona/análogos & derivados , Adulto , Antioxidantes/metabolismo , Suplementos Nutricionais , Exercício Físico/fisiologia , Humanos , Masculino , Pessoa de Meia-Idade , Mitocôndrias/metabolismo , Músculo Esquelético/metabolismo , Coativador 1-alfa do Receptor gama Ativado por Proliferador de Peroxissomo/genética , Coativador 1-alfa do Receptor gama Ativado por Proliferador de Peroxissomo/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Ubiquinona/farmacologia
2.
Appl Physiol Nutr Metab ; 47(7): 762-774, 2022 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-35201920

RESUMO

Unaccustomed exercise causes muscle damage resulting in loss of muscle function, which may be attributable to exercise-induced increases in skeletal muscle reactive oxygen species. This study examined the effect of mitochondria-targeted antioxidant supplementation on recovery of muscle function following exercise. Thirty-two untrained men received MitoQ (20 mg/day) or a placebo for 14 days before performing  300 maximal eccentric contractions of the knee extensor muscles of 1 leg. Muscle function was assessed using isokinetic dynamometry before, immediately after, and 24, 48, 72, and 168 hours after exercise. Muscle soreness was assessed using a visual analogue scale 24, 48, 72, and 168 hours after exercise. Blood samples were collected before, immediately after, and 2, 24, 48, 72, and 168 hours after exercise and urine samples were collected before and during the 48 hours after exercise. The reduction in maximal voluntary isometric contraction force and peak concentric torque following exercise was unaffected by MitoQ while recovery of peak eccentric torque was delayed in the MitoQ group. Exercise-induced increases in urine F2-isoprostanes were unaffected by MitoQ. MitoQ augmented exercise-induced increases in plasma creatine kinase levels, while plasma IL-6 was similar between groups. Muscle soreness was not affected by MitoQ. These results indicate that MitoQ does not attenuate post-exercise muscle soreness and may delay recovery of muscle function following eccentric exercise. Trial registration number: ACTRN12620001089921. Novelty: Post-exercise recovery of maximal voluntary isometric contraction force and peak concentric torque were unaffected by MitoQ. MitoQ delayed post-exercise recovery of peak eccentric torque. Post-exercise muscle soreness was unaffected by MitoQ.


Assuntos
Contração Isométrica , Doenças Musculares , Antioxidantes/farmacologia , Creatina Quinase , Suplementos Nutricionais , F2-Isoprostanos , Humanos , Masculino , Mitocôndrias , Contração Muscular/fisiologia , Músculo Esquelético/fisiologia , Mialgia/prevenção & controle , Torque
3.
J Int Soc Sports Nutr ; 18(1): 58, 2021 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-34419082

RESUMO

BACKGROUND: Exercise increases skeletal muscle reactive oxygen species (ROS) production, which may contribute to the onset of muscular fatigue and impair athletic performance. Mitochondria-targeted antioxidants such as MitoQ, which contains a ubiquinone moiety and is targeted to mitochondria through the addition of a lipophilic triphenylphosphonium cation, are becoming popular amongst active individuals as they are designed to accumulate within mitochondria and may provide targeted protection against exercise-induced oxidative stress. However, the effect of MitoQ supplementation on cycling performance is currently unknown. Here, we investigate whether MitoQ supplementation can improve cycling performance measured as time to complete an 8 km time trial. METHOD: In a randomized, double-blind, placebo-controlled crossover study, 19 middle-aged (age: 44 ± 4 years) recreationally trained (VO2peak: 58.5 ± 6.2 ml·kg- 1·min- 1, distance cycled per week during 6 months prior to study enrollment: 158.3 ± 58.4 km) male cyclists completed 45 min cycling at 70% VO2peak followed by an 8 km time trial after 28 days of supplementation with MitoQ (20 mg·day- 1) and a placebo. Free F2-isoprostanes were measured in plasma samples collected at rest, after 45 min cycling at 70% VO2peak and after completion of the time trial. Respiratory gases and measures of rating of perceived exertion (RPE) were also collected. RESULTS: Mean completion time for the time trial was 1.3% faster with MitoQ (12.91 ± 0.94 min) compared to placebo (13.09 ± 0.95 min, p = 0.04, 95% CI [0.05, 2.64], d = 0.2). There was no difference in RPE during the time trial between conditions (p = 0.82) despite there being a 4.4% increase in average power output during the time trial following MitoQ supplementation compared to placebo (placebo; 270 ± 51 W, MitoQ; 280 ± 53 W, p = 0.04, 95% CI [0.49, 8.22], d = 0.2). Plasma F2-isoprostanes were lower on completion of the time trial following MitoQ supplementation (35.89 ± 13.6 pg·ml- 1) compared to placebo (44.7 ± 16.9 pg·ml- 1 p = 0.03). CONCLUSION: These data suggest that MitoQ supplementation may be an effective nutritional strategy to attenuate exercise-induced increases in oxidative damage to lipids and improve cycling performance.


Assuntos
Antioxidantes/farmacologia , Desempenho Atlético/fisiologia , Ciclismo/fisiologia , Mitocôndrias Musculares/efeitos dos fármacos , Compostos Organofosforados/farmacologia , Substâncias para Melhoria do Desempenho/farmacologia , Ubiquinona/análogos & derivados , Adulto , Antioxidantes/metabolismo , Estudos Cross-Over , Método Duplo-Cego , F2-Isoprostanos/sangue , Humanos , Peroxidação de Lipídeos , Masculino , Pessoa de Meia-Idade , Mitocôndrias Musculares/metabolismo , Músculo Esquelético/metabolismo , Compostos Organofosforados/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Consumo de Oxigênio , Substâncias para Melhoria do Desempenho/metabolismo , Esforço Físico/efeitos dos fármacos , Esforço Físico/fisiologia , Placebos/metabolismo , Placebos/farmacologia , Espécies Reativas de Oxigênio/metabolismo , Fenômenos Fisiológicos da Nutrição Esportiva/efeitos dos fármacos , Fenômenos Fisiológicos da Nutrição Esportiva/fisiologia , Fatores de Tempo , Ubiquinona/metabolismo , Ubiquinona/farmacologia
4.
J Nutr Sci ; 9: e25, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32742642

RESUMO

Diet has a major influence on the composition and metabolic output of the gut microbiome. Higher-protein diets are often recommended for older consumers; however, the effect of high-protein diets on the gut microbiota and faecal volatile organic compounds (VOC) of elderly participants is unknown. The purpose of the study was to establish if the faecal microbiota composition and VOC in older men are different after a diet containing the recommended dietary intake (RDA) of protein compared with a diet containing twice the RDA (2RDA). Healthy males (74⋅2 (sd 3⋅6) years; n 28) were randomised to consume the RDA of protein (0⋅8 g protein/kg body weight per d) or 2RDA, for 10 weeks. Dietary protein was provided via whole foods rather than supplementation or fortification. The diets were matched for dietary fibre from fruit and vegetables. Faecal samples were collected pre- and post-intervention for microbiota profiling by 16S ribosomal RNA amplicon sequencing and VOC analysis by head space/solid-phase microextraction/GC-MS. After correcting for multiple comparisons, no significant differences in the abundance of faecal microbiota or VOC associated with protein fermentation were evident between the RDA and 2RDA diets. Therefore, in the present study, a twofold difference in dietary protein intake did not alter gut microbiota or VOC indicative of altered protein fermentation.


Assuntos
Dieta Rica em Proteínas , Proteínas Alimentares , Microbiota/efeitos dos fármacos , Idoso , Fezes/química , Fezes/microbiologia , Microbioma Gastrointestinal , Humanos , Masculino , Necessidades Nutricionais , Resultado do Tratamento , Compostos Orgânicos Voláteis/análise
5.
Genes Nutr ; 15: 2, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32042348

RESUMO

CONTEXT: Metabolic inflexibility is a characteristic of insulin resistance, limiting the ability to transiently regulate oxidative metabolism and gene expression in response to nutrient availability. Little is known of the flexibility of post-transcriptional regulation, including circulatory miRNAs (c-miRNAs). DESIGN: The abundances of targeted c-miRNAs, with reported functions in metabolic regulation, were analysed in response to a high-carbohydrate meal in healthy weight insulin-sensitive (IS) and overweight insulin-resistant (IR) women. PARTICIPANTS: Age-matched healthy weight IS (n = 20, BMI = 24.3 ± 0.70) and overweight IR (n = 20, BMI = 28.6 ± 0.67) women. METHODS: An abundance of c-miRNAs was quantified prior to and following a high-carbohydrate breakfast meal (2500 kJ; 50% carbohydrate, 20% fat and 27% protein). Target genes of the differentially regulated c-miRNA were measured in RNA extracted from circulatory peripheral blood mononuclear cells (PBMCs). RESULTS: In healthy weight IS women, both miR-15a-5p (p = 0.03) and miR-17-5p (p < 0.01) levels were halved at 4 h post-meal. These miRNA remained unaltered following the same meal in the overweight IR women. Furthermore, amongst genes targeted by these miRNA, CPT1A (p = 0.01) and IL8 (p = 0.03) had also reduced expression 4 h post-meal only in the healthy weight IS women. CONCLUSIONS: The study findings provide preliminary evidence for a possible extension of metabolic inflexibility to include c-miRNAs. TRIAL REGISTRATION: The clinical trial is registered with Australian New Zealand Clinical Trials Registry under Trial registration: ANZCTR: ACTRN12615001108505. Registered on 21 October 2015.

6.
Acta Diabetol ; 57(2): 203-214, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31435783

RESUMO

AIMS: Circulatory microRNAs (c-miRNAs) exert important roles in the molecular dysregulation of cardio-metabolic diseases. However, little is known whether dysregulated miRNA expression occurs when risk factors are elevated, as in the metabolic syndrome (MetS). This study quantified c-miRNA expression in individuals with MetS compared to healthy, further examining the relationship of gene pathways with the underlying pathogenesis. METHODS: Expression of 26 miRNAs was quantified in plasma from 40 women (20 healthy and 20 MetS) and 39 men (20 healthy and 19 MetS) by qPCR. In silico analysis was performed to investigate biological effects of the dysregulated miRNAs. Dysregulated miRNA expression was further validated in an independent cohort of 20 women (10 healthy and 10 MetS). RESULTS: Regression model adjusted for age and sex identified miR-15a-5p, miR-17-5p, miR-370-3p and miR-375 as important predictors of MetS presence. Analysis of predictive miRNAs in the validation cohort strengthened the relationship with miR-15a-5p and miR-17-5p expression. These miRNAs share genes involved in the regulation of metabolic pathways including insulin, wnt, fatty acid metabolism and AMPK. CONCLUSIONS: miR-15a-5p and miR-17-5p were identified as predictive biomarkers of MetS, irrespective of sexes, further demonstrating the relationship of c-miRNAs to known pathways of metabolic disturbances present in cardio-metabolic diseases.


Assuntos
Síndrome Metabólica/sangue , MicroRNAs/sangue , Adulto , Biomarcadores/sangue , Estudos de Coortes , Feminino , Humanos , Masculino , Síndrome Metabólica/diagnóstico , Síndrome Metabólica/genética , MicroRNAs/genética , Pessoa de Meia-Idade , Reação em Cadeia da Polimerase em Tempo Real
7.
J Nutr Health Aging ; 23(4): 354-363, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30932134

RESUMO

BACKGROUND: The mammalian target of rapamycin complex 1 (mTORC1) is fundamental for many cellular processes, yet it is often dysregulated with aging. Increased amino acid (AA) availability is correlated with the expression of AA transporters (AAT) and mTORC1 activity. Although many AA sensors and mediators have been proposed to relay the AA signal to mTORC1, it has not yet been determined if chronic dietary intervention affects the expression of AAT, sensors and mediators and their relationships with mTORC1 activity. OBJECTIVE AND DESIGN: This study investigated whether the consumption of a diet containing either the current recommended daily allowance (RDA) of protein intake (0.8 g/kg/d) or twice the RDA (2RDA) for ten weeks affected the expression of targets associated with AA transport, sensing and mTORC1 regulation in 26 older men (70-81 years). METHOD: Muscle biopsies were collected before and after the intervention under fasting conditions. Diets were controlled by providing fully prepared meals and snacks. Western blot and quantitative polymerase chain reaction were used to measure protein and gene expression respectively. RESULTS: Consumption of 2RDA reduced the protein expression of L-type amino acid transporter 1 (LAT1). However, plasma leucine concentration and basal mTORC1 activity were unaltered. The downregulation of LAT1 did not affect the expression of AA sensors and mediators, including leucyl tRNA synthetase (LRS), cytosolic arginine sensor for mTORC1 (CASTOR1), Sestrin2 and Rag proteins. Instead, total ribosomal protein S6 (RPS6) was upregulated with 2RDA. CONCLUSION: Ten weeks of 2RDA diet did not affect the fasting mTORC1 signaling, but increased total RPS6 might suggest improved muscular translational capacity to maintain muscular mass.


Assuntos
Dieta Rica em Proteínas , Transportador 1 de Aminoácidos Neutros Grandes/metabolismo , Alvo Mecanístico do Complexo 1 de Rapamicina/metabolismo , Músculo Esquelético/fisiologia , Idoso , Idoso de 80 Anos ou mais , Envelhecimento , Índice de Massa Corporal , Humanos , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Leucina/química , Masculino , Complexos Multiproteicos , Recomendações Nutricionais , Proteína S6 Ribossômica/metabolismo , Transdução de Sinais
8.
J Appl Physiol (1985) ; 126(2): 454-461, 2019 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-30571281

RESUMO

Measurement of skeletal muscle mitochondrial respiration requires invasive biopsy to obtain a muscle sample. Peripheral blood mononuclear cell (PBMC) mitochondrial protein content appears to reflect training status in young men; however, no studies have investigated whether there are training-induced changes in PBMC mitochondrial respiration. Therefore, we determined whether PBMC mitochondrial respiration could be used as a marker of skeletal muscle mitochondrial respiration in young healthy men and whether PBMC mitochondrial respiration responds to short-term training. Skeletal muscle and PBMC samples from 10 healthy young (18-35 yr) male participants were taken before and after a 2-wk high-intensity interval training protocol. High-resolution respirometry was used to determine mitochondrial respiration from muscle and PBMCs, and Western blotting and quantitative PCR were used to assess mitochondrial biogenesis in PBMCs. PBMC mitochondrial respiration was not correlated with muscle mitochondrial respiration at baseline ( R2 = 0.012-0.364, P > 0.05). While muscle mitochondrial respiration increased in response to training (32.1-61.5%, P < 0.05), PBMC respiration was not affected by training. Consequently, PBMCs did not predict training effect on muscle mitochondrial respiration ( R2 = 0.024-0.283, P > 0.05). Similarly, gene and protein markers of mitochondrial biogenesis did not increase in PBMCs following training. This suggests PBMC mitochondrial function does not reflect that of skeletal muscle and does not increase following short-term high-intensity training. PBMCs are therefore not a suitable biomarker for muscle mitochondrial function in young healthy men. It may be useful to study PBMC mitochondrial function as a biomarker of muscle mitochondrial function in pathological populations with different respiration capacities. NEW & NOTEWORTHY Research in primates has suggested that peripheral blood mononuclear cells (PBMCs) may provide a less-invasive alternative to a muscle biopsy for measuring muscle mitochondrial function. Furthermore, trained individuals appear to have greater mitochondrial content in PBMCs. Here we show that in healthy young men, PBMCs do not reflect skeletal muscle mitochondrial function and do not adapt in response to a training intervention that increases muscle mitochondrial function, suggesting PBMCs are a poor marker of muscle mitochondrial function in humans.


Assuntos
Metabolismo Energético , Treinamento Intervalado de Alta Intensidade , Leucócitos Mononucleares/metabolismo , Mitocôndrias Musculares/metabolismo , Músculo Esquelético/metabolismo , Adaptação Fisiológica , Adolescente , Adulto , Fatores Etários , Biomarcadores/metabolismo , Respiração Celular , Voluntários Saudáveis , Humanos , Masculino , Proteínas Mitocondriais/genética , Proteínas Mitocondriais/metabolismo , Fosforilação Oxidativa , Fatores Sexuais , Fatores de Tempo , Adulto Jovem
9.
J Dairy Sci ; 100(6): 4230-4234, 2017 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-28434749

RESUMO

Whey protein concentrate (WPC) is a high-quality dairy ingredient that is often included in formulated food products designed to stimulate muscle anabolism. Whey protein concentrate can be affected by UHT processing, and its sensory properties are not compatible with some formulated food products. Microparticulated WPC (mWPC) is a novel ingredient that is resistant to heat treatment and has enhanced sensory properties. When 16 healthy middle-aged men consumed 20 g of either WPC or mWPC, both proteins increased plasma essential AA and leucine concentrations with no detectable difference in curve kinetics. Myofibrillar protein synthesis was increased in both groups for 90 min after ingestion with no difference between groups. Ingestion of mWPC resulted in a muscle anabolic response that was equivalent to that of WPC over the full 210-min measurement period. Formulated products incorporating mWPC or standard WPC would provoke equivalent anabolic responses.


Assuntos
Anabolizantes/farmacocinética , Alimentos Formulados , Proteínas Musculares/biossíntese , Proteínas do Soro do Leite/farmacologia , Aminoácidos Essenciais/sangue , Anabolizantes/administração & dosagem , Animais , Manipulação de Alimentos , Temperatura Alta , Humanos , Leucina/sangue , Masculino , Pessoa de Meia-Idade , Fatores de Tempo , Proteínas do Soro do Leite/administração & dosagem
10.
Am J Physiol Regul Integr Comp Physiol ; 310(5): R432-9, 2016 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-26632603

RESUMO

A high-saturated-fat diet (HFD) during pregnancy and lactation leads to metabolic disorders in offspring concomitant with increased adiposity and a proinflammatory phenotype in later life. During the fetal period, the impact of maternal diet on skeletal muscle development is poorly described, despite this tissue exerting a major influence on life-long metabolic health. This study investigated the effect of a maternal HFD on skeletal muscle anabolic, catabolic, and inflammatory signaling in adult rat offspring. Furthermore, the actions of maternal-supplemented conjugated linoleic acid (CLA) on these measures of muscle phenotype were investigated. A purified control diet (CD; 10% kcal fat), a CD supplemented with CLA (CLA; 10% kcal fat, 1% total fat as CLA), a high-fat (HFD; 45% kcal fat from lard), or a HFD supplemented with CLA (HFCLA; 45% kcal fat from lard, 1% total fat as CLA) was fed ad libitum to female Sprague-Dawley rats for 10 days before mating and throughout gestation and lactation. Male offspring received a standard chow diet from weaning, and the gastrocnemius was collected for analysis at day 150. Offspring from HF and HFCLA mothers displayed lower muscular protein content accompanied by elevated monocyte chemotactic protein-1, IL-6, and IL-1ß concentrations. Phosphorylation of NF-κBp65 (Ser(536)) and expression of the catabolic E3 ligase muscle ring finger 1 (MuRF1) were increased in HF offspring, an effect reversed by maternal CLA supplementation. The present study demonstrates the importance of early life interventions to ameliorate the negative effects of poor maternal diet on offspring skeletal muscle development.


Assuntos
Dieta Hiperlipídica , Inflamação/prevenção & controle , Ácidos Linoleicos Conjugados/administração & dosagem , Músculo Esquelético/efeitos dos fármacos , Atrofia Muscular/prevenção & controle , Efeitos Tardios da Exposição Pré-Natal , Fenômenos Fisiológicos da Nutrição Animal , Animais , Composição Corporal , Citocinas/genética , Citocinas/metabolismo , Modelos Animais de Doenças , Feminino , Regulação da Expressão Gênica , Inflamação/genética , Inflamação/metabolismo , Inflamação/patologia , Mediadores da Inflamação/metabolismo , Masculino , Fenômenos Fisiológicos da Nutrição Materna , Proteínas Musculares/genética , Proteínas Musculares/metabolismo , Músculo Esquelético/metabolismo , Músculo Esquelético/patologia , Atrofia Muscular/genética , Atrofia Muscular/metabolismo , Atrofia Muscular/patologia , Gravidez , Complexo de Endopeptidases do Proteassoma/genética , Complexo de Endopeptidases do Proteassoma/metabolismo , Ratos Sprague-Dawley , Transdução de Sinais/efeitos dos fármacos , Serina-Treonina Quinases TOR/genética , Serina-Treonina Quinases TOR/metabolismo , Aumento de Peso
11.
R Soc Open Sci ; 2(10): 150270, 2015 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-26587242

RESUMO

We have demonstrated a bidirectional wavelength division (de)multiplexer (WDM) on the silicon-on-insulator platform using two 4-channel angled multimode interferometers (AMMIs) sharing the same multimode interference waveguide. An excellent match of the peak transmission wavelength of each channel between the two AMMIs was achieved. The input and output access waveguides were arranged in a configuration such that the propagation of light of one AMMI in the multimode interference waveguide suffered minimal perturbation by the input and output waveguides of the other AMMI. This type of device is ideal for the WDM system for datacom or telecom applications, e.g. an integrated optical transceiver, where the transmission wavelengths are required to match with the receiving wavelengths. The device also benefits from simple fabrication (as only a single lithography and etching step is required), improved convenience for the transceiver layout design, a reduction in tuning power and circuitry and efficient use of layout space. A low insertion loss of 3-4 dB, and low crosstalk of -15 to -20 dB, was achieved.

12.
J Nutr Health Aging ; 19(8): 839-45, 2015 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-26412288

RESUMO

OBJECTIVES: To measure the postprandial plasma amino acid appearance in younger and older adults following a high protein mixed meal. DESIGN: Cross-sectional study. SETTING: Clinical research setting. PARTICIPANTS: Healthy men and women aged 60-75 (n=15) years, and young controls aged 20-25 years (n=15) matched for body mass index and insulin sensitivity based on the homeostatic model assessment of insulin resistance. INTERVENTION: High protein mixed meal of complete food products. MEASUREMENTS: Circulating amino acid concentrations were determined hourly before and for 5 hours after meal ingestion. RESULTS: There was no difference between cohorts in postprandial appearance of non-essential amino acids, or area under the curve of any individual amino acid or amino acid class. However, older adults had higher baseline concentrations of aspartic acid, glutamic acid, glycine, ornithine, threonine and tyrosine and lower baseline concentrations of hydroxyproline, isoleucine, leucine, methionine and valine compared to younger adults. Younger adults showed peak essential (EAA) and branched-chain amino acid (BCAA) concentrations at 1 hour post meal while older adults' peak EAA and BCAA concentration was at 3 hours. Similarly, peak total amino acid concentrations were at 3 hours in older adults. CONCLUSION: Older adults digested and absorbed the protein within a mixed meal more slowly than younger adults. Delayed absorption of AA following a mixed meal of complete food products may suppress or delay protein synthesis in senescent muscle.


Assuntos
Aminoácidos de Cadeia Ramificada/metabolismo , Aminoácidos Essenciais/metabolismo , Proteínas Alimentares/metabolismo , Adulto , Idoso , Envelhecimento , Aminoácidos de Cadeia Ramificada/sangue , Aminoácidos Essenciais/sangue , Índice de Massa Corporal , Desjejum , Estudos Transversais , Proteínas Alimentares/sangue , Ingestão de Alimentos , Feminino , Humanos , Resistência à Insulina , Masculino , Pessoa de Meia-Idade , Período Pós-Prandial , Adulto Jovem
13.
Opt Lett ; 39(6): 1406-9, 2014 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-24690799

RESUMO

A low-cost and high-performance wavelength division (de)multiplexing structure in the mid-IR wavelength range is demonstrated on the silicon-on-insulator platform using an interleaved angled multimode interferometer (AMMI). As compared to a single AMMI, the channel count was doubled and the channel spacing halved with negligible extra insertion loss and crosstalk and with only a slight increase in device footprint. The device requires only single lithography and etching steps for fabrication. Potential is also shown for achieving improved performance with further optimized design.

14.
Malawi Med J ; 25(3): 88-9, 2013 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-24358427

RESUMO

An outbreak of Tunga Penetrans (Jigger Flea) infestation affecting a number of villages near to a Central Hospital in Malawi is described. Due to the large number of affected individuals, high parasitic load, and extended duration of infection an alternative to the recommended approach of surgical removal of the flea was required. Benzyl benzoate paint and liquid paraffin had been used in local Primary Healthcare settings previously and topical treatment with antiparasitic agents has been advocated in the literature, particularly for severe infestation. Benzyl benzoate and liquid paraffin were applied topically to four adults with numerous jigger flea burrows, and their progress assessed regularly. After completion of 7 days of treatment patients noted that fleas were dislodging spontaneously, and that embedded parasites had not increased in size to the same extent that untreated fleas had in previous infestations. Following confirmation of the viability of its implementation in a resource-poor setting, this treatment regimen has subsequently been adopted by the local branch of the District Health Office for distribution to infected communities.


Assuntos
Benzoatos/administração & dosagem , Inseticidas , Tunga , Tungíase/terapia , Administração Cutânea , Adulto , Animais , Humanos , Malaui , Resultado do Tratamento
16.
Environ Geochem Health ; 31(4): 503-9, 2009 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-18792795

RESUMO

A robust and rapid methodology for the determination of iodine by inductively coupled plasma mass spectrometry in environmental samples is presented. Data were initially obtained for the validation of the analytical measurements, using 17 commercially available soil reference materials. The methodology was then tested on soil and water samples collected in Afghanistan where iodine deficiency and its effects are reportedly prevalent. Sample collections were conducted in Greater Kabul; the iodine in agricultural soils was determined to be in the range of 1.6-4.2 mg/kg and that in water drawn for drinking and irrigation was found to range from 9.9 to 22.7 microg/L. Samples were also collected in a second region, Nangarhar province, which is located to the east of Kabul, where goitres in the local population had been reported. The iodine content in soils and water at this location was 0.5-1.9 mg/kg and 5.4-9.4 microg/L, respectively. The organic content of soils in Kabul was found to be in the range of 1.9-4.2%; in Nangarhar, organic content ranged from 1.7 to 4.5%. All of the Afghan soils were slightly alkaline at pH 7.6-8.2.


Assuntos
Iodo/análise , Poluentes do Solo/análise , Afeganistão , Monitoramento Ambiental , Água Doce/química , Humanos , Iodo/deficiência , Espectrometria de Massas , Projetos Piloto , Solo/análise , Abastecimento de Água/análise
17.
Science ; 311(5767): 1587-9, 2006 Mar 17.
Artigo em Inglês | MEDLINE | ID: mdl-16543455

RESUMO

The spokes are intermittently appearing radial markings in Saturn's B ring that are believed to form when micrometer-sized dust particles are levitated above the ring by electrostatic forces. First observed by the Voyagers, the spokes disappeared from October 1998 until September 2005, when the Cassini spacecraft saw them reappear. The trajectories of the charged dust particles comprising the spokes depend critically on the background plasma density above the rings, which is a function of the solar elevation angle. Because the rings are more open to the Sun now than when Voyager flew by, the charging environment above the rings has prevented the formation of spokes until very recently. We show that this notable effect is capable of stopping spoke formation entirely and restricting the size of the particles in the spokes.

18.
Br J Surg ; 93(1): 87-93, 2006 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-16288452

RESUMO

BACKGROUND: Bacterial translocation (BT) describes the passage of bacteria from the gastrointestinal tract to normally sterile tissues such as the mesenteric lymph nodes (MLNs) and other internal organs. The clinical and pathophysiological significance of BT remains controversial. This report describes results obtained over a 13-year period of study. METHODS: MLNs were obtained from 927 patients undergoing laparotomy. Nasogastric aspirates were obtained from 458 (49.4 per cent) of 927 patients for culture; pH was measured in 172 (37.6 per cent) of 458. Preoperative clinical variables were evaluated and factors that influenced BT were included in a multivariate logistic regression analysis. RESULTS: BT was identified in 130 (14.0 per cent) of 927 patients. Postoperative sepsis was more common in patients with BT (42.3 versus 19.9 per cent; P < 0.001). Independent preoperative variables associated with BT were emergency surgery (P = 0.001) and total parenteral nutrition (TPN) (P = 0.015). Gastric colonization was confirmed in 248 (54.1 per cent) of 458 patients, and was associated with both BT (P = 0.015) and postoperative sepsis (P = 0.029). A gastric pH of less than 4 was associated with a significant reduction in gastric colonization (53 versus 80 per cent; P < 0.001) and postoperative sepsis (46 versus 70.3 per cent; P = 0.018) but not BT. CONCLUSION: BT is associated with postoperative sepsis. Emergency surgery and TPN are independently associated with an increased prevalence of BT.


Assuntos
Translocação Bacteriana/fisiologia , Trato Gastrointestinal/microbiologia , Complicações Pós-Operatórias/microbiologia , Sepse/microbiologia , Idoso , Feminino , Humanos , Concentração de Íons de Hidrogênio , Masculino , Pessoa de Meia-Idade , Nutrição Parenteral , Análise de Regressão
19.
Acta Physiol Scand ; 182(2): 171-7, 2004 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-15450113

RESUMO

AIM: Conventional dual sugar tests of intestinal permeability assess only the stomach and small intestine. A novel triple sugar method of assessing colonic permeability has recently been described in animals. This utilizes the non-fermented sweetener sucralose, in addition to conventional sugars. It has been postulated that this test enables the simultaneous assessment of small-intestinal and colonic barrier function in humans. The aim of this study was to evaluate the triple sugar test using healthy volunteers and ileostomists. METHODS: Twenty-one healthy volunteers and 18 ileostomists underwent the triple sugar test. After an overnight fast, subjects drank a solution containing lactulose (5 g), rhamnose (1 g) and sucralose (5 g). Urine was collected for 0-5 h and 5-19 h. Urinary sugars were quantified using HPLC, and 5 and 24-h excretion calculated. Nineteen control subjects and 16 ileostomists also underwent a 51Cr-EDTA permeability test. Permeability data were presented as medians (IQR), and differences between groups analysed with Mann-Whitney U-tests. RESULTS: Lactulose excretion and the 5-h lactulose/rhamnose (L/R) ratio were similar in controls and ileostomists [L/R ratio 0.024 (0.022-0.034) vs. 0.025 (0.022-0.035), P = 0.955]. Twenty-four hours excretion of sucralose was significantly higher in control subjects compared with ileostomists [1.41% (1.17-1.68) vs. 0.96% (0.64-1.2), P = 0.003]. The same pattern was seen with 51Cr-EDTA [2.73% (2.06-3.76) vs. 2.06% (1.55-2.71), P = 0.037] and with lactulose [0.52% (0.42-0.60) vs. 0.25% (0.16-0.35), P = 0.002]. CONCLUSIONS: Both sucralose and 51Cr-EDTA underwent significant colonic absorption. A significant amount of lactulose also appeared to be absorbed in the colon. This unexpected finding requires further study.


Assuntos
Colo/metabolismo , Técnicas de Diagnóstico do Sistema Digestório , Lactulose , Sacarose/análogos & derivados , Adulto , Idoso , Testes Respiratórios/métodos , Feminino , Humanos , Hidrogênio/análise , Ileostomia , Lactulose/urina , Masculino , Pessoa de Meia-Idade , Permeabilidade , Ramnose/urina , Sacarose/urina , Edulcorantes/administração & dosagem
20.
Br J Surg ; 90(12): 1497-504, 2003 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-14648727

RESUMO

BACKGROUND: Multimodal optimization of surgical care has been associated with reduced hospital stay and improved physical function. The aim of this randomized trial was to compare multimodal optimization with standard care in patients undergoing colonic resection. METHODS: Twenty-five patients requiring elective right or left hemicolectomy were randomized to receive a ten-point optimization programme (14 patients) or conventional care (11). The groups were similar in terms of age (64 versus 68 years), male : female sex ratio (6 : 8 versus 5 : 6) and Physiological and Operative Severity Score for the enUmeration of Mortality and morbidity (POSSUM) score (both 26). Outcome measures were recorded before operation and on postoperative days 1, 7 and 30. They included hand grip strength, lung spirometry, and pain and fatigue scores. Further outcome measures included time to achieve a predetermined mobilization target, time to resumption of normal diet, and length of stay. RESULTS: Optimization was associated with maintained grip strength, earlier mobilization (46 versus 69 h; P = 0.043), and significantly lower pain and fatigue scores. Patients in the optimization group tolerated a regular hospital diet significantly earlier than controls (48 versus 76 h; P < 0.001). Optimization significantly reduced the median length of hospital stay (3 versus 7 days; P = 0.002). CONCLUSION: Optimization of surgical care significantly improved patients' physical and psychological function in the early postoperative period and facilitated early hospital discharge.


Assuntos
Colectomia/métodos , Doenças do Colo/cirurgia , Assistência Perioperatória/métodos , Idoso , Analgésicos/administração & dosagem , Protocolos Clínicos , Doenças do Colo/fisiopatologia , Deambulação Precoce , Fadiga/etiologia , Feminino , Volume Expiratório Forçado/fisiologia , Força da Mão , Humanos , Tempo de Internação , Masculino , Pessoa de Meia-Idade , Dor Pós-Operatória/prevenção & controle , Dor Pós-Operatória/psicologia , Complicações Pós-Operatórias , Recuperação de Função Fisiológica , Índice de Gravidade de Doença , Fatores de Tempo , Resultado do Tratamento
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