View clinical trials related to Energy Metabolism.
Filter by:The aim is to define in detail metabolic pathways at rest and during aerobic exercise in normal and healthy men and women under normobaric normoxic and moderate hypoxic conditions, using metabolomics technologies based on minimally invasive sampling relying on gas chromatography and mass spectrometry.
At this time, 24h energy expenditure is rarely assessed under free-living conditions for specific individuals because of the lack of cheap and accurate software/materials to record the energy expenditure. Some affordable and convenient tools (Polar heart rate monitor, Actiheart, SenseWear Armband) are available on the market but the predictive equations comprised into the software provided with these tools generally miscalculate the energy expenditure (by about +/-10%). Because of this deficiency, the investigators have a poor knowledge of the modification of the energy expended during daily life activities and over 24h in subjects belonging to groups of various ages and physiological states. The investigators hypothesise that it could be possible to improve the energy expenditure prediction. The project aims at providing a mathematical model (equations) that predicts energy expenditure with an error near to 5%. Two groups of 60 sedentary to athletic normal weight volunteers aged between 18-60 years participate to this study. The first group stay for 26h in calorimetric chambers. During this stay energy expenditure ,heart rate, accelerometry, and other parameters are recorded during various activities. These data will serve to construct the model. The same type of recordings are performed on second group of volunteers in free living conditions. Their energy expenditure is measured overall by doubly labeled water. The data of the second group will serve to validate the model. The error percentage of the model is defined by the ratio of the value of the difference between prediction and reference measure to the reference measure. Concordance between predictions and measures will be evaluated by Bland - Altman plots.
The Salty Life 7 study aimed to examine the effect of a high salt (sodium chloride, NaCl) intake on different forms of sodium retention, acid-base balance and bone metabolism and other influenced physiological systems. Because of the fact that astronauts are a vulnerable group in this context, they were of special interest. Astronauts have a high salt intake, probably because of a reduced sense of taste, as well as an increased bone resorption resulting from the lowered mechanical load in space. In which forms sodium could be retained even without fluid retention (osmotically inactive)- contrary to the argumentation of physiological text books - and if the acid-base balance is connected to sodium chloride induced bone loss is examined in a stationary bed rest study with 8 healthy, young, male test subjects. The study consisting of 2 x 21 days is carried out at the German Aerospace Center (DLR). After an adaptation period of 4 days, test subjects are immobilised in 6° head-down tilt bed rest (simulation model for some physiological changes in space) for 14 days during which they received a high (7.7 mmol NaCl/kgBW/d) and a low salt (0.7 mmol NaCl/kgBW/d) intake in cross-over design. The form of sodium retention is investigated by the calculation of daily metabolic sodium-, water- and potassium balances and by changes in body weight. The measurements of bone formation (bAP, PINP, Osteocalcin) markers as well as bone resorption markers (CTX, NTX) supply insight into the influences of a high salt intake on bone metabolism. Blood gas analysis and ph values of 24-h urine are used to gather information about accompanying changes in the acid-base balance. Further physiological systems like energy metabolism and circulation system are also under investigation.
During weaning from mechanical ventilation process, the energy expenditure in T tube is greater than pressure support ventilation.
The investigators are developing two new medical instruments: 1. the Intelligent Sensor Belt (ISB), and 2. the Body Composition and Hydration Status Analyzer (BC-HS-A). ISB serves the purpose of measuring calorie/ energy consumption of the human body during physical activity. The BC-HS-A measures the body composition, i.e. the fat and lean body mass and the hydration status i.e the amount of water inside and outside of the body cells. The goal of this pilot study is to obtain data from the investigators prototype medical instruments: 1. ISB, and 2. BC-HS-A during physical exercise and compare those results with readings of other commercially available instruments or exercise equipments. The investigators would be testing for technical feasibility and, through comparison with existing measuring devices, the reliability of the investigators prototype.
Lifestyle choices,including diet,are conducive to healthy body weights in children. Dairy products and calcium supplementation have been associated with moderation of body weight and body fat. This study was designed to test the following hypotheses with overweight and obese adolescents consuming a controlled diet: - Dietary calcium supplementation as calcium carbonate or dairy calcium modulates energy balance in adolescents. - Increased calcium in the diet of adolescents will increase fecal fat excretion and thereby decrease fat absorption. - Calcium and dairy product supplementation will increase lipid oxidation resulting in an increase in energy expenditure.
The metabolic response to Crohn's disease, including increased proteolysis and lipolysis and changes in energy expenditure, plays a significant role in the resulting malnutrition from which these patients suffer. Tumor necrosis factor-alpha (TNF-alpha), a pro-inflammatory cytokine, has been found to be elevated in children with ulcerative colitis. TNF-alpha has been incriminated in the mechanism of weight loss in many different chronic diseases, and causes net protein and lipid catabolism. Anti-TNF-alpha antibody (infliximab) has been proven to be an effective therapy for ulcerative colitis. The purpose of this study is to compare changes in protein and lipid metabolism, as well as resting energy expenditure, before and after therapy with anti-TNF-alpha antibody (infliximab) or corticosteroids in children with recurrent Crohn's disease. Performing this study will better define the changes in nutrition status observed in these children following remission of active Crohn's disease, and potentially lead to changes in medical and nutritional management of these children.