259 resultados para Energy functioning
Resumo:
The thermogenic response induced by ethanol ingestion in humans has not been extensively studied. This study was designed to determine the thermic effect of ethanol added to a normal diet in healthy nonalcoholic subjects, using indirect calorimetry measurements over a 24-h period in a respiration chamber. The thermic effect of ethanol was also measured when ethanol was ingested in the fasting state, using a ventilated hood system during a 5-h period. Six subjects ingested 95.6 +/- 1.8 (SE) g ethanol in 1 day partitioned over three meals; there was a 5.5 +/- 1.2% increase in 24-h energy expenditure compared with a control day in which all conditions were identical except that no ethanol was consumed. The calculated ethanol-induced thermogenesis (EIT) was 22.5 +/- 4.7% of the ethanol energy ingested. Ingestion of 31.9 +/- 0.6 g ethanol in the fasting state led to a 7.4 +/- 0.6% increase in energy expenditure over baseline values, and the calculated EIT was 17.1 +/- 2.2%. It is concluded that in healthy nonalcoholic adults ethanol elicits a thermogenic response equal to approximately 20% of the ethanol energy. Thus the concept of the apparently inefficient utilization of ethanol energy is supported by these results which show that only approximately 80% of the ethanol energy is used as metabolizable energy for biochemical processes in healthy nonalcoholic moderate ethanol consumers.
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BACKGROUND: Psychological stress negatively influences food intake and food choices, thereby contributing to the development of childhood obesity. Physical activity can also moderate eating behavior and influence calorie intake. However, it is unknown if acute physical activity influences food intake and overall energy balance after acute stress exposure in children. We therefore investigated the impact of acute physical activity on overall energy balance (food intake minus energy expenditure), food intake, and choice in the setting of acute social stress in normal weight (NW) and overweight/obese (OW/OB) children as well as the impact of psychological risk factors. METHOD: After receiving written consent from their parents, 26 NW (BMI < 90(th) percentile) and 24 7-to 11-year-old OW (n = 5)/OB (n = 19, BMI ≥ 90(th) percentile) children were randomly allocated using computer-generated numbers (1:1, after stratification for weight status) to acute moderate physical or to sedentary activity for 30 min. Afterwards, all children were exposed to an acute social stressor. Children and their parents completed self-report questionnaires. At the end of the stressor, children were allowed to eat freely from a range of 12 different foods (6 sweet/6 salty; each of low/high caloric density). Energy balance, food intake/choice and obesity-related psychological risk factors were assessed. RESULTS: Lower overall energy balance (p = 0.019) and a decreased choice of low density salty foods (p < 0.001) in NW children compared with OW/OB children was found after acute moderate physical activity but not sedentary activity. Independent of their allocation, OW/OB children ate more high density salty foods (104 kcal (34 to 173), p = 0.004) following stress. They scored higher on impulsive behavior (p = 0.005), restrained eating (p < 0.001) and parental corporal punishment (p = 0.03), but these psychological factors were not related to stress-induced food intake/choice. Positive parenting tended to be related to lower intake of sweet high density food (-132 kcal, -277 to 2, p = 0.054). CONCLUSIONS: In the setting of stress, acute moderate physical activity can address energy balance in children, a benefit which is especially pronounced in the OW/OB. Positive parenting may act as a protective factor preventing stress-induced eating of comfort food. TRIAL REGISTRATION: clinicaltrials.gov NCT01693926 The study was a pilot study of a project funded by the Swiss National Science Foundation (CRSII3_147673).
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The magnitude of variability in resting energy expenditure (REE) during the day was assessed in nine healthy young subjects under two nutritional conditions: 1) mixed nutrient (53% carbohydrate, 30% fat, 17% protein) enteral feeding at an energy level corresponding to 1.44 REE; and 2) enteral fasting, with only water allowed. In each subject, six 30-min measurements of REE were performed using indirect calorimetry (hood system) at 90-min intervals from 9 AM to 5 PM. The mean REE and respiratory quotient were significantly (p less than .01) greater during feeding than during fasting (1.08 +/- 0.07 [SEM] vs. 1.00 +/- 0.06 kcal/min and 0.874 +/- 0.007 vs. 0.829 +/- 0.008 kcal/min, respectively). Mean postprandial thermogenesis was 4.9 +/- 0.4% of metabolizable energy administered. The intraindividual variability of REE throughout the day, expressed as the coefficient of variation, ranged from 0.7% to 2.0% in the fasting condition and from 1.2% to 4.1% in the feeding condition. There was no significant difference between the REE measured in the morning and that determined in the afternoon.
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We perform direct numerical simulations of drainage by solving Navier- Stokes equations in the pore space and employing the Volume Of Fluid (VOF) method to track the evolution of the fluid-fluid interface. After demonstrating that the method is able to deal with large viscosity contrasts and to model the transition from stable flow to viscous fingering, we focus on the definition of macroscopic capillary pressure. When the fluids are at rest, the difference between inlet and outlet pressures and the difference between the intrinsic phase average pressure coincide with the capillary pressure. However, when the fluids are in motion these quantities are dominated by viscous forces. In this case, only a definition based on the variation of the interfacial energy provides an accurate measure of the macroscopic capillary pressure and allows separating the viscous from the capillary pressure components.
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Cannabis use is highly prevalent among people with schizophrenia, and coupled with impaired cognition, is thought to heighten the risk of illness onset. However, while heavy cannabis use has been associated with cognitive deficits in long-term users, studies among patients with schizophrenia have been contradictory. This article consists of 2 studies. In Study I, a meta-analysis of 10 studies comprising 572 patients with established schizophrenia (with and without comorbid cannabis use) was conducted. Patients with a history of cannabis use were found to have superior neuropsychological functioning. This finding was largely driven by studies that included patients with a lifetime history of cannabis use rather than current or recent use. In Study II, we examined the neuropsychological performance of 85 patients with first-episode psychosis (FEP) and 43 healthy nonusing controls. Relative to controls, FEP patients with a history of cannabis use (FEP + CANN; n = 59) displayed only selective neuropsychological impairments while those without a history (FEP - CANN; n = 26) displayed generalized deficits. When directly compared, FEP + CANN patients performed better on tests of visual memory, working memory, and executive functioning. Patients with early onset cannabis use had less neuropsychological impairment than patients with later onset use. Together, these findings suggest that patients with schizophrenia or FEP with a history of cannabis use have superior neuropsychological functioning compared with nonusing patients. This association between better cognitive performance and cannabis use in schizophrenia may be driven by a subgroup of "neurocognitively less impaired" patients, who only developed psychosis after a relatively early initiation into cannabis use.
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A short review has been made of the experimental studies performed in man, in which the effect of dexfenfluramine (D-F) on resting energy expenditure has been explored. It appears that the extent to which D-F possesses thermogenic properties (in addition to its anorectic effect) still remains controversial. Some investigators found either no significant increase in energy expenditure in response to the drug or a moderate effect in post-absorptive and/or postprandial state. It may be reasonable to assume that the supplementary weight loss observed with D-F as compared to a placebo can be primarily attributed to its anorectic effect rather than to its putative thermogenic effect.
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Although all brain cells bear in principle a comparable potential in terms of energetics, in reality they exhibit different metabolic profiles. The specific biochemical characteristics explaining such disparities and their relative importance are largely unknown. Using a modeling approach, we show that modifying the kinetic parameters of pyruvate dehydrogenase and mitochondrial NADH shuttling within a realistic interval can yield a striking switch in lactate flux direction. In this context, cells having essentially an oxidative profile exhibit pronounced extracellular lactate uptake and consumption. However, they can be turned into cells with prominent aerobic glycolysis by selectively reducing the aforementioned parameters. In the case of primarily oxidative cells, we also examined the role of glycolysis and lactate transport in providing pyruvate to mitochondria in order to sustain oxidative phosphorylation. The results show that changes in lactate transport capacity and extracellular lactate concentration within the range described experimentally can sustain enhanced oxidative metabolism upon activation. Such a demonstration provides key elements to understand why certain brain cell types constitutively adopt a particular metabolic profile and how specific features can be altered under different physiological and pathological conditions in order to face evolving energy demands.
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To assess the effect of weight loss on resting metabolic rate (RMR), the energy expenditure of eight obese prepubertal children (age 9 +/- 1 years; weight 48.7 +/- 9.1 kg; BMI 25.3 +/- 3.9) and of 14 age-matched children of normal body weight (age 9 +/- 1 years; weight 28.8 +/- 5.6 kg; BMI 16.5 +/- 1.7) was measured by indirect calorimetry. The obese children were reinvestigated after a mean weight loss of 5.4 +/- 1.2 kg induced by a six-months mixed hypocaloric diet. Before slimming, the obese group showed a higher daily energy intake than the control group (10.40 +/- 3.45 MJ/day vs 7.97 +/- 2.02 MJ/day respectively; P less than 0.05) but a similar value was observed per unit fat-free mass (FFM) (0.315 +/- 0.032 MJ/kgFFM/day vs 0.329 +/- 0.041 MJ/kgFFM/day respectively). The average RMR of the obese children was greater than that of the control group (5217 +/- 531 kJ/day vs 4477 +/- 506 kJ/day) but similar after adjusting for FFM (4728 +/- 3102 kJ/day vs 4899 +/- 3102 kJ/day). Weight loss resulted in a reduction in RMR (5217 +/- 531 kJ/day vs 4874 +/- 820 kJ/day), each kg of weight loss being accompanied by a decrease of RMR of 64 kJ (15.3 kcal) per day. The changes in RMR induced by weight loss paralleled the changes in FFM. No difference was found in average RQ in obese children vs controls (0.85 +/- 0.03 vs 0.87 +/- 0.03 respectively) and in the obese children before and after weight loss (0.87 +/- 0.02).(ABSTRACT TRUNCATED AT 250 WORDS)
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The increase in weight, fat and energy content of queens was studied in Iridomyrmex humilis (Mayr) in relation to the mode of colony founding in ants. The increase in energy content of gynes during the time between emergence and mating reaches only 80% in this species in which queens found colonies with the help of workers (dependent mode), whereas it can reach 470% in species in which queens found colonies without the help of workers (independent mode). These results are discussed with regard to the investment in energy required by each mode of colony founding.
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INTRODUCTION: The influence of specific health problems on health-related quality of life (HRQoL) in childhood cancer survivors is unknown. We compared HRQoL between survivors of childhood cancer and their siblings, determined factors associated with HRQoL, and investigated the influence of chronic health problems on HRQoL. METHODS: Within the Swiss Childhood Cancer Survivor Study, we sent a questionnaire to all survivors (≥16 years) registered in the Swiss Childhood Cancer Registry, who survived >5 years and were diagnosed 1976-2005 aged <16 years. Siblings received similar questionnaires. We assessed HRQoL using Short Form-36 (SF-36). Health problems from a standard questionnaire were classified into overweight, vision impairment, hearing, memory, digestive, musculoskeletal or neurological, and thyroid problems. RESULTS: The sample included 1,593 survivors and 695 siblings. Survivors scored significantly lower than siblings in physical function, role limitation, general health, and the Physical Component Summary (PCS). Lower score in PCS was associated with a diagnosis of central nervous system tumor, retinoblastoma or bone tumor, having had surgery, cranio-spinal irradiation, or bone marrow transplantation. Lower score in Mental Component Summary was associated with older age. All health problems decreased HRQoL in all scales. Most affected were survivors reporting memory problems and musculoskeletal or neurological problems. Health problems had the biggest impact on physical functioning, general health, and energy and vitality. CONCLUSIONS: In this study, we showed the negative impact of specific chronic health problems on survivors' HRQoL. IMPLICATIONS FOR CANCER SURVIVORS: Therapeutic preventive measures, risk-targeted follow-up, and interventions might help decrease health problems and, consequently, improve survivors' quality of life.
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Developing a novel technique for the efficient, noninvasive clinical evaluation of bone microarchitecture remains both crucial and challenging. The trabecular bone score (TBS) is a new gray-level texture measurement that is applicable to dual-energy X-ray absorptiometry (DXA) images. Significant correlations between TBS and standard 3-dimensional (3D) parameters of bone microarchitecture have been obtained using a numerical simulation approach. The main objective of this study was to empirically evaluate such correlations in anteroposterior spine DXA images. Thirty dried human cadaver vertebrae were evaluated. Micro-computed tomography acquisitions of the bone pieces were obtained at an isotropic resolution of 93μm. Standard parameters of bone microarchitecture were evaluated in a defined region within the vertebral body, excluding cortical bone. The bone pieces were measured on a Prodigy DXA system (GE Medical-Lunar, Madison, WI), using a custom-made positioning device and experimental setup. Significant correlations were detected between TBS and 3D parameters of bone microarchitecture, mostly independent of any correlation between TBS and bone mineral density (BMD). The greatest correlation was between TBS and connectivity density, with TBS explaining roughly 67.2% of the variance. Based on multivariate linear regression modeling, we have established a model to allow for the interpretation of the relationship between TBS and 3D bone microarchitecture parameters. This model indicates that TBS adds greater value and power of differentiation between samples with similar BMDs but different bone microarchitectures. It has been shown that it is possible to estimate bone microarchitecture status derived from DXA imaging using TBS.
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Two hybrid compounds comprising an antimetastatic ruthenium-arene fragment tethered to an indazole-3-carboxylic acid derivative that inhibits aerobic glycolysis in cancer cells have been prepared and evaluated in a variety of cancer cell lines, including highly relevant human glioblastoma cells, with an apparent synergistic action between the two components observed.