A5080928184- Diet and metabolism studies
- Muscle metabolism and nutrition
- Metabolism and Genetic Disorders
- Nutritional Studies and Diet
- Metabolomics and Mass Spectrometry Studies
- Clinical Nutrition and Gastroenterology
- Nutrition, Genetics, and Disease
- Metabolism, Diabetes, and Cancer
- Hyperglycemia and glycemic control in critically ill and hospitalized patients
- Diet, Metabolism, and Disease
- Diabetes Management and Research
- Pancreatic function and diabetes
- Obesity, Physical Activity, Diet
- Adipose Tissue and Metabolism
- Growth Hormone and Insulin-like Growth Factors
- Biochemical effects in animals
- Birth, Development, and Health
- Mitochondrial Function and Pathology
- Sports Performance and Training
- Amino Acid Enzymes and Metabolism
- Exercise and Physiological Responses
- Mass Spectrometry Techniques and Applications
- Cardiovascular and exercise physiology
- Consumer Attitudes and Food Labeling
- Diabetes and associated disorders
Harvard University
1982-2024
Baylor College of Medicine
2003-2024
Children's Nutrition Research Center at Baylor College of Medicine
2015-2024
McMaster University
2024
Impact
2024
Emory University
2024
American Society for Nutrition
2017
Agricultural Research Service
1999-2016
National University of Singapore
2013
Assistance Publique – Hôpitaux de Paris
2012
To determine the plasma epinephrine thresholds for its metabolic and hemodynamic actions clearance rates, 60-min intravenous infusions at nominal rates of 0.1, 0.5, 1.0, 2.5, 5.0 microgram/min were performed in each six normal human subjects. These 30 resulted steady-state concentrations ranging from 24 to 1,020 pg/ml. Plasma 50-100 pg/ml increments heart rate, 75-125 blood glycerol systolic pressure, 150-200 glucose (the resultant production decrements clearance), lactate,...
Leucine metabolism in vivo can be determined from a primed, continuous infusion of L-[1-13C]leucine by measuring, at isotopic steady state, plasm [-13C]leucine enrichment, expired 13CO2 and CO2 production rate. With an appropriate priming dose NaH13CO3, state is reached less than 2 h, the completed 4 h. The method determine rates leucine turnover, oxidation, incorporation into protein with typical relative uncertainties 2, 10, 4%, respectively. requires no more 1 ml blood uses stable isotope...
Saw Swee Hock School of Public Health, National University Singapore, Department Paediatrics, Yong Loo Lin Medicine, Obstetrics & Gynaecology, Health System, Singapore Institute for Clinical Sciences, Agency Science and Technology Research (A*STAR), Brenner Centre Molecular Liggins Institute, Auckland, New Zealand, Medical Council Lifecourse Epidemiology Unit, Southampton, UK, NIHR Southampton Biomedical Centre, Hospital NHS Foundation Trust, Biostatistics KK Women’s Children’s Hospital,
"New" glucose production has been measured in 54 infants and children for the first time by continuous three-to-four-hour influsion of safe, nonradioactive tracer 6,6-dideuteroglucose. The use combined gas chromatography--mass spectrometry with monitoring selected ions allowed deuterium enrichment blood to be on microliter samples an error less than 2 per cent. In young child, increased a slightly curvilinear manner from 1 kg. 25 body weight, when it reached 140 mg. minute, almost adult...
Muscle mass and function are improved in the elderly during resistance exercise training. These improvements must result from alterations rates of muscle protein synthesis breakdown. We determined rate quadriceps using vivo incorporation intravenously infused [13C]leucine into mixed-muscle both young (24 yr) (63-66 men women before at end 2 wk Before training, fractional was lower than (0.030 +/- 0.003 vs. 0.049 0.004%/h; P = 0.004) but increased (P < 0.03) to a comparable (0.075...
During intravenous insulin infusions (40 mU per kilogram of body weight hour for up to 100 minutes), 9 22 patients with insulin-requiring diabetes mellitus had neurologic signs or symptoms hypoglycemia, plasma glucose concentrations that were below 35 mg deciliter (1.9 mmol liter) and continued decline, both. This inadequate counterregulation resulted from the combined effect deficient glucagon epinephrine responses. In 8 severe hypoglycemia developed during subsequent intensive therapy,...
In vivo effects of insulin on plasma leucine and alanine kinetics were determined in healthy postabsorptive young men (n = 5) employing 360-min primed, constant infusions L-[1-13C]leucine L-[15N]alanine during separate single rate euglycemic infusions. Serum concentrations 16.4 +/- 0.8, 29.1 2.7, 75.3 5.0, 2,407 56 microU/ml achieved. Changes 3-methyl-histidine (3-MeHis) obtained as an independent qualitative indicator insulin-mediated reduction proteolysis. Hepatic glucose output was...
Glucose and leucine metabolism in 18 severely burned patients were studied using the primed constant infusion of U-13C-glucose l-13C-leucine, respectively. The data used to calculate rates whole-body protein synthesis. In four additional burn seven normal controls, effects exogenously infused insulin on glucose evaluated. Also, effect adding was tested synthesis calculated. studies divided into two groups depending rate infusion. Protein 4.3 + 0.54 g protein/kg/day during lower (1.4–4.5...
To evaluate the role of glucagon in pathogenesis diabetic ketoacidosis man, we studied effect suppression secretion by somatostatin on changes plasma beta-hydroxybutyrate and glucose concentrations (as well as their precursors) after acute withdrawal insulin from seven patients with juvenile-type diabetes. Suppression prevented development for 18 hours withdrawal, whereas control studies mild occurred 10 was stopped. Plasma beta-hydroxybutyrate, glucose, free fatty acid, glycerol levels were...
Lipoprotein lipase forms an enzyme-substrate complex with fat emulsions in the presence of serum lipoproteins. Lipoproteins very low density and high have this property, but former are much more active per unit weight protein. In investigation, activity, expressed as quantity giving half-maximal rate production free fatty acids, specific glycopeptides isolated from lipoproteins was tested incubation mixture containing lipoprotein cows' milk 1.8 mg triglyceride ml. The two major polypeptides...
The purpose of this study was to determine whether growth hormone (GH) administration enhances the muscle anabolism associated with heavy-resistance exercise. Sixteen men (21-34 yr) were assigned randomly a resistance training plus GH group (n = 7) or placebo 9). For 12 wk, both groups trained all major in an identical fashion while receiving 40 micrograms recombinant human GH.kg-1.day-1 placebo. Fat-free mass (FFM) and total body water increased (P less than 0.05) but more 0.01) recipients....
Whole-body leucine and lysine metabolism was explored in young adult men by a primed constant intravenous infusion of mixture L-[1-13C]leucine L-[alpha-15N]lysine over 4-h period. Subjects were studied after an overnight fast (postabsorptive state) or while consuming hourly meals (fed adaptation to diets providing either surfeit level protein (1.5 g.kg body-1.day-1), approximating maintenance requirements (marginal intake) (0.6 body wt-1.day-1), grossly inadequate (0.1 g.kg-1.day-1). The...
The purpose of this study was to determine whether growth hormone (GH) administration enhances the muscle protein anabolism associated with heavy-resistance exercise training in older men. Twenty-three healthy, sedentary men (67 +/- 1 yr) low serum insulin-like factor I levels followed a 16-wk progressive resistance program (75-90% max strength, 4 days/wk) after random assignment either GH (12.5-24 micrograms.kg-1.day-1; n = 8) or placebo (n 15) group. Fat-free mass (FFM) and total body...
Plasma free fatty acid (FFA) levels tend to be lower and the plasma lipolytic hormone response prolonged exercise of same intensity is blunted after endurance training. To determine whether training elicits a corresponding decrease in FFA turnover metabolism during exercise, we measured [1-13C]palmitate kinetics oxidation respiratory gas exchange 13 subjects latter portion 90- 120-min bout cycle ergometer work performed before 12 wk alternate-day cycling running. Training increased total fat...
Patients with major injury or illness develop protein wasting, hypermetabolism, and hyperglycemia increased glucose flux. To assess the role of elevated counterregulatory hormones in this response, we simultaneously infused cortisol (6 mg/m2 per h), glucagon (4 ng/kg min), epinephrine (0.6 microgram/m2 norepinephrine (0.8 micrograms/m2 min) for 72 h into five obese subjects receiving only intravenous (150 g/d). Four received alone under identical conditions. Combined infusion maintained...
To assess the effects of endurance training on plasma glucose kinetics during moderate-intensity exercise in men, seven men were studied before and after 12 wk strenuous (3 days/wk running, 3 cycling). After priming bicarbonate pools, [U-13C] was infused continuously 2 h cycle ergometer at 60% pretraining peak O2 uptake (VO2) to determine turnover oxidation. Training increased VO2 by 23% decreased respiratory exchange ratio final 30 min from 0.89 +/- 0.01 0.85 (SE) (P less than 0.001)....
To study the individual effects of glucagon and growth hormone on human carbohydrate lipid metabolism, endogenous secretion both hormones was simultaneously suppressed with somatostatin physiologic circulating levels one or other were reproduced by exogenous infusion. The interaction these insulin evaluated performing studies in juvenile-onset, insulin-deficient diabetic subjects during infusion after its withdrawal. Infusion (1 ng/kg-min) suppression produced approximately 200 pg/ml. When...
To study glutamate and glutamine kinetics, 4-h unprimed intravenous infusions of L-[15N]glutamate, L-[2-15N]glutamine, L-[5-15N]-glutamine were administered to healthy young adult male subjects in the postabsorptive state. Arterialized-venous blood samples drawn analyzed for 15N enrichments. The fractional turnover rates tracer-miscible pools fast, 8.0 2.8% min-1, respectively. pool accounted less than one-tenth estimated free body. plasma amino N, N amide appearance 83 +/- 22 (means SD),...
Leucine catabolism is regulated by either of the first two degradative steps: (reversible) transamination to keto acid or subsequent decarboxylation. A method described measure rates leucine transamination, reamination, and oxidation. The applied directly humans infusing nonradioactive tracer, L-[ 15 N,1- 13 C]leucine. was found be operating several times faster than decarboxylation equal magnitude in adult human males under different dietary conditions, postabsorptive fed. These results...