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Biomedical subjects

C Fedou

Publications and source records attributed to C Fedou.

14 recordsLinked to original sources
PubMed2003

Serum levels of insulin-like growth factor-I (IGF-I), and IGF-binding proteins-1 and -3 in middle-aged and young athletes versus sedentary men: relationship with glucose disposal.

The goal of this study was to characterize the respective effects of aging and endurance training on serum insulin-like growth factor I (IGF-I), as well as IGF-binding proteins (IGFBP)-1 and -3 in relationship with glucose disposal. Thirty-two subjects (16 middle-aged men: 8 cyclists and 8 sedentary men; and 16 young men: 8 cyclists and 8 sedentary men) were compared in this study. Insulin sensitivity (SI) and glucose effectiveness (Sg) were assessed by the minimal model. Endurance training increased SI, Sg, and IGFBP-1 and -3 in both age groups (P<.05), but the older group showed a greater increase in SI and IGFBP-1 than the younger group (P<.05). IGF-I was increased only in the middle-aged trained men (P<.05). An effect of aging was found in the sedentary subjects, who presented lower IGF-I and SI (P<.05) when older. This effect disappeared with training since IGF-I and SI were nearly identical in young and middle-aged trained subjects. SI was correlated with IGFBP-1 (P<.01). These data suggest that (1) endurance training increases SI, Sg, and IGFBP-1 and -3 in men and, for SI and IGFBP-1, this increase becomes more pronounced with age; (2) endurance training may attenuate the aged-related decline in SI and IGF-I; and (3) IGFBP-1 may protect against the risk of hypoglycemia by counteracting the hypoglycemic effect of IGF-I in such situations of high SI.

Adult↗
PubMed2003

Low intensity endurance exercise targeted for lipid oxidation improves body composition and insulin sensitivity in patients with the metabolic syndrome.

BACKGROUND: To investigate the effects of individualized training on the metabolic syndrome. METHODS: Twenty-eight patients, suffering from the metabolic syndrome were studied before and after 2 months of training and compared to eleven patients who did not follow any training. All the patients were overweight. Training was individualized at the point where fat oxidation was maximal (LIPOX(max)) as determined by calorimetry. RESULTS: The patients exhibited a significant reduction in body weight (- 2.6 +/- 0.7 kg; P=0.002), fat mass (- 1.55 +/- 0.5 kg; P=0.009), waist (- 3.53 +/- 1.3 cm; P<0.05) and hip (- 2.21 +/- 0.9 cm; P<0.05) circumferences, and improved the ability to oxidize lipids at exercise (crossover point: + 31.7 +/- 5.8 W; P<0.0001; LIPOX(max): + 23.5 +/- 5.6 W; P<0.0001; lipid oxidation: + 68.5 +/- 15.4 mg.min(-1); P=0.0001). No clear improvement in either lipid parameters or fibrinogen were observed. The surrogates of insulin sensitivity evidenced a decrease in insulin resistance: HOMA%S (software): + 72.93 +/- 32.64; p<0.05; HOMA-IR (simplified formula): - 2.42 +/- 1.07; P<0.05; QUICKI: + 0.02 +/- 0.004; P<0.01; SI=40/I: + 3.28 +/- 1.5; P<0.05. Significant correlations were found between changes in body weight and HOMA-IR and between changes in LIPOX(max) and QUICKI. CONCLUSIONS: Individualized aerobic training improves lipid oxidation, body composition and insulin resistance.

Adipose Tissue↗
PubMed2002

Does growth hormone treatment alter skeletal muscle mitochondrial respiration in rats?

OBJECTIVE: Growth hormone (GH) has been shown to stimulate lipolysis and enhance lipid oxidation. We investigated whether GH could improve mitochondrial oxidative capacity. METHOD: Fourteen male Wistar rats received 14-day treatment with biosynthetic human GH (10 IU/kg/24 h) or placebo. Mitochondria were isolated from the total muscle of one hind limb of the rat. Mitochondrial oxygen consumption was measured in vitro using a Clark-type electrode with three substrates: palmitoyl-L-carnitine, pyruvate and succinate (+ rotenone). RESULTS: Muscle mitochondrial yield was not significantly different in the GH-treated group from that in controls. Neither the basal nor ADP-stimulated respiratory state reached a significant difference between the 2 groups with palmitoyl-L-carnitine, pyruvate, and succinate. CONCLUSION: GH treatment did not improve the oxidative capacity of skeletal muscle mitochondria.

Adenosine Diphosphate↗
PubMed2002

Reduction of fat accumulation and lipid disorders by individualized light aerobic training in human immunodeficiency virus infected patients with lipodystrophy and/or dyslipidemia.

BACKGROUND: The management of abdominal fat accumulation and metabolic disorders in HIV1-infected patients, by an aerobic training program, is considered. METHODS: Seventeen lipodystrophic and 2 dyslipidemic (without body modification) adults were studied before and after 4 months of training. The training load was individualized on a ventilatory threshold basis, determined during a maximal exercise test on cycle ergometer. Total (TAT), Visceral (VAT) and Subcutaneous Adipose Tissue (SAT) were assessed by CT-scan. Total (TC) and High Density Lipoprotein (HDL-C) Cholesterol, Triglycerides (TG), lactate (La), insulin and glucose were measured after a 12-hour-overnight fast. LDL, TC/HDL, TG/HDL, HOMA-insulin resistance index and coronary heart disease (CHD) relative risk (RR(CHD)) were calculated. RESULTS: Besides a significant improvement of aerobic fitness, trained patients exhibited a reduction in TAT (-12.8%, p < 0.001), specially at the visceral level (- 12%, p < 0.01) and in TC, TG and La (- 23%, - 43% and - 19% respectively, p < 0.01). HDL-C was increased (+ 6%, p < 0.01). All these effects were above changes that could be expected by a possible regression to the mean artefact. Both TC/HDL and TG/HDL were reduced (p < 0.01) and the estimated RR(CHD) decreased by approximately 13% (p < 0.01). No significant training effect was observed on the 9 available HOMAs. Significant correlations were found between changes in blood lipid values and baseline measures (r range - 0.55 to - 0.79, p < 0.05), indicating a larger improvement when baseline lipid parameters were higher. CONCLUSION: Aerobic training reduced visceral fat, lipid disorders, basal blood lactate and CHD markers in HIV patients. Training effects were particularly important for patients with marked dyslipidemia.

Adipose Tissue↗
PubMed2001

Exercise hypoglycemia in nondiabetic subjects.

Hypoglycemia during exercise is a common event due to an unbalance between training volume, nutrition, and external influences such as chronobiology, temperature or altitude, in subjects characterized by an acute and chronic increase in glucose effectiveness and insulin sensitivity. While it is preventable by adequate pre-exercise feeding with carbohydrates, it can also be induced by a prior carbohydrate meal with high glycemic index. Adequate training induces resistance to hypoglycemia via a shift in the balance of oxidized substrates and marked hormonal adaptations, but overtraining, by partially reversing this adaptation, favorizes hypoglycemia. Exercise hypoglycemia is a cause of fatigue or exercise cessation, but also impairs thermoregulatory adaptation and is assumed to fragilize muscles and tendons for traumatic events.

Dietary Carbohydrates↗
PubMed2000

Postprandial reactive hypoglycemia.

Postprandial reactive hypoglycemia (PRH) can be diagnosed if sympathetic and neuroglucopenic symptoms develop concurrently with low blood sugar (<3.3 mmol). Neither the oral glucose tolerance test (OGTT) nor mixed meals are suitable for this diagnosis, due to respectively false positive and false negative results. They should be replaced by ambulatory glycemic control or, as recently proposed, an hyperglucidic breakfast test. PRH patients often suffer from an associated adrenergic hormone postprandial syndrome, with potential pathologic consequences such as cardiac arrhythmia. PRH could result from (a) an exaggerated insulin response, either related to insulin resistance or to increased glucagon-like-peptide 1; (b) renal glycosuria; (c) defects in glucagon response; (d) high insulin sensitivity, probably the most frequent cause (50-70%), which is not adequately compensated by hypoinsulinemia and thus cannot be measured by indices of insulin sensitivity such as the homeostatic model assessment. Such situations are frequent in very lean people, or after massive weight reduction, or in women with moderate lower body overweight. PRH is influenced by patient's alimentary habits (high carbohydrate-low fat diet, alcohol intake). Thus, diet remains the main treatment, although alpha-glucosidase inhibitors and some other drugs may be helpful.

Blood Glucose↗
PubMed1999

Serum leptin is associated with the perception of palatability during a standardized high-carbohydrate breakfast test.

Leptin is an adipocyte-derived signalling molecule which plays a key role in the regulation of body weight and energy expenditure. Since its involvement in human eating behaviour is still poorly understood, we investigated whether the perception of palatability of food was related to fasting serum leptin levels. Twenty-six non-diabetic subjects, six men and twenty women of widely ranging age and body mass index, performed a standardized high-carbohydrate breakfast test. Palatability was evaluated with a visual analogue scale, body composition by bioelectrical impedance, serum leptin and plasma insulin by radioimmunoassay. Palatability was correlated to fasting serum leptin levels independently of body mass index, body fat mass and percentage of body fat (P<0.01). No significant relation was observed with peaks of insulinaemia, integrated concentrations of insulin or insulin resistance indices. A stepwise regression analysis indicated that serum leptin gave the strongest predictive association with palatability. These results suggest that the leptin system may be involved in the regulation of human eating behaviour in relation to the perception of palatability of food.

Adult↗
PubMed1995

Effects of zamic as a means for zinc supplementation in growing children.

We investigated the effects of zinc supplementation in case of moderate growth retardation in which GH treatment could not be used. Zamic (ZA, an association containing arginine, L-methionine, and zinc; from Aguettant pharmaceuticals) was compared with arginine aspartate (AA) (5 g) in a crossover randomized trial (6 mo of each treatment at random order over 1 yr). We present preliminary results of 24 children who completed the study (3 girls, 21 boys, age 9-13 yr). Subjects had to be prepubertal, with no GH deficiency diagnosed. In 15 subjects growth velocity was lower than 5 mm/mo: In this case ZA improved growth velocity (rising from 3.105 +/- 0.229 to 5.4 +/- 0.69 mm/mo p < 0.01), whereas the effect of AA was not significant. The increase in growth velocity was higher with ZA (+2.44 +/- 0.657 mm/mo) than AA (+0.438 +/- 0.450 mm/mo) p < 0.05. These results suggest that ZA is more efficient than AA, consistent with the hypothesis that zinc needs are increased in those children in this period of life.

Adolescent↗
PubMed1993

[Study of urinary excretion of testosterone and epitestosterone glucuronides in children and adolescents].

Urinary testosterone to epitestosterone ratio (T/E) is used as a marker for illegal exogenous testosterone use. Mean value in healthy adults is 1.13 and 6 is the upper limit of the accepted range. Urinary excretion of these two steroids were studied in 57 children and teenagers at different pubertal stages, using gas chromatography coupled with mass spectrometry with selective ion detection. Urinary excretion of testosterone and epitestosterone increased significantly during puberty. Mean T/E ratio remained fairly constant but interindividual variations were marked and in one subject the T/E ratio exceeded 6. These data suggest that this test may yield false-positive results in adolescents.

Adolescent↗
PubMed1991

Increased albumin excretion rate during a standardized exercise-test in diabetics with lowered blood filterability.

Albumin excretion rate in urine is a marker of early, reversible stages of diabetic nephropathy. Does abnormal blood rheology represent an additional risk factor in this multifactorial process? We investigated a possible link between red cell filterability and microalbuminuria during an exercise test (exercise is supposed to improve the detection of excessive microalbuminuria). 77 diabetics (27 females, 50 males, age: 15-60 yr) underwent a 20 min inframaximal progressively increasing workload on cycloergometer, rising heart rate up to 200 minus the age. Filterability of whole blood and washed red cells were measured on 5 microns polycarbonate sieves reused after ultrasonic cleaning. Whole blood filterability was found to be impaired in 35 subjects (group A) and normal in 41 (group B). Groups A and B were matched for age, sex, blood pressure, glycemic equilibrium, and duration of disease. Microalbuminuria was higher in A at rest (39.79 +/- 13.83 micrograms/min vs 12.9 +/- 3.21, p less than 0.01) and after exercise (91.80 +/- 20.79 vs 42.23 +/- 7.85, p less than 0.01). The slopes of regression lines between resting Microalbuminuria and blood pressure were greater in group A than in group B (p less than 0.01). No relationship between microalbuminuria and washed red cell filterability was detected. This study confirms on a larger scale a previous report of our team. Some hemorheologic disorders detectable with whole blood filterability (but not with washed red cell filtration) are associated with an increase in resting and postexercise microalbuminuria.

Adolescent↗
PubMedDate not supplied

Serum zinc in highly trained adolescent gymnasts.

Serum zinc was measured in 20 adolescent gymnasts (9 boys, 11 girls, age 12-15 yr) explored for detecting possible adverse effects of intense training on pubertal maturation and growth. They had low serum zinc (0.599 +/- 0.026 mg/L) when compared to matched control sedentary children (n = 118 mean 0.81 +/- 0.014 p < 0.001). Girls had lower zinc than boys (0.557 +/- 0.023 vs 0.651 +/- 0.044 p < 0.001). Zinc was correlated to isometric adductor strength (r = 0.468 p < 0.05). Children with serum zinc < 0.6 mg/L had lower insulin-like growth factor binding protein 3 than others (2.326 +/- 0.264 vs 2.699 +/- 0.12 p < 0.01). Thus, zinc is lowered in trained adolescent gymnasts and even lower in females. This reduction could play some role in abnormalities of puberty, growth, or muscular performance.

Adolescent↗
PubMedDate not supplied

Effects of oral zinc gluconate on glucose effectiveness and insulin sensitivity in humans.

Zinc improves both insulin secretion and insulin sensitivity, and exerts insulin-like effects. We investigated its acute effects on the parameters of glucose assimilation determined with the minimal model technique from frequent sampling intravenous glucose tolerance test (FSIVGTT) in seven healthy volunteers. FSIVGTTs (0.5 g/kg of glucose, followed by 2 U insulin i.v. injection at 19 min) were performed after the subjects had taken 20 mg zinc gluconate twice (the evening before and 30 min before the beginning of the test) or placebo pills (simple blind randomized protocol). Glucose assimilation was analyzed by calculating Kg (slope of the exponential decrease in glycemia), glucose effectiveness Sg (i.e., ability of glucose itself to increase its own disposal independent of insulin response), and SI (insulin sensitivity, i.e. the effect of increases in insulinemia on glucose disposal). The two latter parameters were calculated by fitting the experimental data with the two equations of Bergman's "minimal model." Zinc increased Kg (p < 0.05) and Sg (p < 0.05), whereas SI and insulin first-phase secretion did not significantly increase. This study suggests that zinc improves glucose assimilation, as evidenced by the increase in Kg, and that this improvement results mainly from an increase in glucose effectiveness (insulin-like effect), rather than an action on insulin response or insulin sensitivity.

Administration, Oral↗