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Biomedical subjects

J Coudert

Publications and source records attributed to J Coudert.

At least 73 records · Page 4Linked to original sources
PubMed1989

Catecholamines and fuels after an ultralong run: persistent changes after 24-h recovery.

This study examined the alterations induced by an ultralong distance run (169 +/- 6 km in 24 h) and by prolonged postrace recovery (24 h) on blood fuel metabolites and catecholamines in seven trained subjects. Ten minutes after the race, plasma concentrations of glycerol and free fatty acids (FFA) were decreased twofold. Plasma glucose was unchanged. Plasma concentrations of free norepinephrine (NE) and free dopamine (DA) increased from 2.73 +/- 0.28 to 5.41 +/- 1.11 nmol.l-1 and from 0.45 +/- 0.13 to 0.62 +/- 0.18 nmol.l-1 whereas free epinephrine (E) and insulin were unchanged; 24 h after the race, plasma glycerol and FFA concentrations remained elevated (twofold) and TG decreased twofold compared with resting levels. Concomitantly, plasma NE and DA levels remained elevated, respectively, 6.23 +/- 0.41 and 0.77 +/- 0.13 nmol.l-1. These data show that the alterations in circulating fuel metabolites and NE induced by the ultralong race were still present 24 h later. The involvement of lipid metabolism and catecholamines in processes of post-exercise recovery is discussed.

Adult↗
PubMed1989

Hormonal, fluid, and electrolyte changes during a 72-h recovery from a 24-h endurance run.

To examine body fluid regulation over 72 h of recovery from a 24-h endurance race, changes in plasma volume (delta PV) and plasma aldosterone (A), cortisol (CO), antidiuretic hormone (ADH), and atrial natriuretic peptide (ANP) were studied in nine male runners before (C) and after (1-2 h = D0; 24 h = D1; 48 h = D2; 72 h = D3) the race, 24-h urine collections were made 1 week before (C), during the 24-h race/U0), and during the 3 days following the end of the race (U1, U2, and U3). On D0 delta PV decreased (2%). A, CO and ADH increased (380%, 200%, and 133%, respectively, from C values) and ANP decreased (68%). No significant changes were found in sodium, potassium, osmolality in plasma, in 24-h urine volume (UV), and natriuresis (Na+). Urinary potassium excretion (K+) increased (256% from C value). During the 3 days of recovery delta PV rose markedly with a peak on D2 (24%) and remained elevated on D3 (15%). CO, ADH, and ANP returned to baseline on D1 and A on D3. Significant inverse effects were observed on ADH (P less than 0.001) and ANP (P less than 0.01): from C values, ADH decreased (21% and 29%) and ANP increased (41% and 58%) on D2 and D3, respectively. UV and Na+ were depressed on D1 and D2. This study shows that the hormonal responses observed immediately after the 24-h run favored a relative fluid conservation. The hypervolemia that occurred during the 3-day recovery was related to renal responses on D1 and D2 and appeared to be the primary factor in the hormonal responses on D2 and D3.

Adult↗
PubMed1989

Calf sweat lactate in peripheral arterial occlusive disease.

The energy metabolism of sweat glands was studied to evaluate the reduction in oxygen delivery in the tissue of patients with peripheral arterial occlusive disease. We compared lactate concentration in pilocarpine-iontophoresis sweat collected from the middle calf area ([ L]sw) of 10 healthy subjects (group 1) and 84 patients suffering from intermittent claudications (group 2, n = 49), from rest pain (group 3, n = 21), and from severe ischemic skin changes (group 4, n = 14). In addition, the effect of a vasoactive drug (naftidrofuryl, 600 mg) or placebo infusion on [L]sw was investigated (n = 30). Results (means +/- SE) showed that 1) [L]sw (mmol/l) increased significantly with the severity of the symptoms: group 1 = 16.5 +/- 0.4, group 2 = 18.7 +/- 0.4, group 3 = 22.8 +/- 0.9, and group 4 = 27.5 +/- 2.0; and 2) [L]sw was reduced by 10% (P less than 0.01) after naftidrofuryl infusion, whereas there was no change after placebo infusion. We suggest that lactate in calf sweat is a good indicator in the evaluation of the severity of peripheral occlusive arterial disease and in assessing the efficiency of vasoactive drug treatment.

Aged↗
PubMed1988

Enzymatic and hormonal responses following a 24 h endurance run and a 10 h triathlon race.

Muscle cell leakage and hormonal changes were compared immediately after and during the 3 days following a 24 h endurance run (R24h) in 8 subjects, and a 10 h triathlon non-competitive race (T10h) in 6 subjects. The study showed three main differences: 1) plasma enzyme increases were considerably more significant in R24h than in T10h: compared with resting levels, creatine kinase increased x 120 after R24h but only x 2 after T10h; lactic dehydrogenase x 4, as opposed to x 1.5; and transaminases only showed an increase after R24h. The plasma myoglobin increase after R24h was double that found after T10h; 2) for the same magnitude of plasma aldosterone and cortisol after R24h and T10h (3 times the resting levels), a highly significant decrease in urinary Na+ (p less than 0.001) and an increase in urinary K+ (p less than 0.01) were found only after R24h; and 3) the plasma free noradrenaline level increased significantly after R24h (x 2.6) whereas it was unchanged after T10h. In contrast, the plasma level of conjugated dopamine increased only after T10h (x 3.7, p less than 0.05). These results suggest that long-distance running causes more muscular lesions than the triathlon, and that important factors other than aldosterone are probably involved in the regulation of urinary electrolyte excretions during T10h.

Adult↗
PubMed1988

Anaerobic metabolism during pubertal development at high altitude.

In a previous study we showed that there were no differences in anaerobic metabolism between groups of 11-yr-old children living at high (3,700 m) and low (330 m) altitudes. The aim of this study is to investigate changes in this metabolism during pubertal development. We compare blood lactate concentration ([L]) after maximal bicycle exercise in 20 boys acclimatized to high altitude (HA, 12 yr old) and at low altitude in 14 boys (LA1, 12 yr old) and in 13 boys (LA2, 14 yr old). The subjects had the same level of physical fitness and the same nutritional and socioeconomic status. Pubertal development was identified by salivary testosterone concentration ([T]). Results (means +/- SE) showed 1) at the age of 12 years, [L] and [T] in HA were significantly higher than in LA1 ([L] was 9.2 +/- 0.5 vs. 6.8 +/- 0.5 mmol/l, [T] was 233 +/- 66 vs. 132 +/- 30 pmol/l), 2) [L] and [T] in HA were statistically the same as in LA2, and 3) a linear relationship between [L] and [T] was significant (P less than 0.05) in all HA and LA subjects. This suggests that the higher [L] in 12-yr-old boys living at HA could result in an enhanced anaerobic metabolism linked to an earlier gonadal maturation evaluated by testosterone level.

Adolescent↗
PubMed1986

Oxygen debt in submaximal and supramaximal exercise in children at high and low altitude.

The effect of high altitude (HA) on O2 debt and blood lactate concentration [( L]) was examined in 10- to 13-yr-old children who exhibited the same level of physical fitness. Fifty-one children acclimatized to HA (3,700 m) were compared with 40 children living at low altitude (LA, 330 m) during submaximal (20-95% maximal aerobic power, MAP), maximal and supramaximal (115% MAP) bicycle exercise. Results showed that 1) maximal O2 uptake (VO2max) and maximal heart rate were significantly (P less than 0.001) lower at HA than at LA by 15% and 11 beats X min-1, respectively; 2) for a given absolute work load, O2 debt was higher at HA than at LA, and the slopes of the linear relationships between O2 debt and O2 uptake were significantly higher at HA; 3) when related to percent of VO2max, O2 debts in HA and LA were similar; for 115% MAP maximal O2 debt and [L] were not significantly different (maximal O2 debt, 45.7 +/- 2.7 and 45.9 +/- 3.8 ml X kg-1; [L], 6.0 +/- 0.3 and 6.7 +/- 0.5 mM); and 4) linear relationships between maximal O2 debt and [L] were the same at HA and LA. This suggests that HA did not modify the anaerobic capacity in children.

Adolescent↗
PubMed1985

Thermal sweat lactate in cystic fibrosis and in normal children.

We attempt to determine whether the decrease in Na+ reabsorption and the increase in K+ secretion in sweat of cystic fibrosis patients (CF) were associated with changes in glandular anaerobic metabolism evaluated by forehead sweat lactate excretion rate. 6 CF and 11 normal (C) children, 5 months to 14 years old, were exposed to external thermal load (45 degrees C). The data showed that: 1) Na+, K+ and Cl- concentrations in CF are constant at any flow rate (Qsw); 2) In both groups the excretion rates of Na+, K+ and Cl- increased linearly with Qsw but the slopes in CF were significantly higher than in C (p less than 0.001); 3) Lactate excretion rate increased with Qsw as in CF and C with the same slope. We suggest that an increase in energy expenditure of Na+ - K+ exchange and an active secretion of K+ by the duct could explain the normal energy metabolism that we observed in CF sweat glands.

Child↗
PubMed1985

Effects of endurance training on the androgenic response to exercise in man.

Six healthy subjects, aged 35.8 +/- 4.4 years, volunteered to participate in a 40-week training program on a bicycle ergometer [three 60-min sessions per week at 80%-85% of maximal oxygen uptake (VO2 max)]. Before training and at the 10th, 20th, 30th, and 40th weeks of the training program, plasma testosterone, cortisol, and androstenedione concentrations were measured at rest (t0) and at the end (t60) of a 1-h endurance exercise requiring 85%-90% of VO2 max. Training resulted in significant increases of anaerobic threshold (12.6%) and VO2 max (7.3%). The training program did not significantly alter the resting values of plasma testosterone, androstenedione, and cortisol; in contrast, the exercise responses (delta = t60-t0) of testosterone, androstenedione, and cortisol were increased. The highest amplitude of these responses was reached at the 30th week for cortisol and androstenedione and at the 40th for testosterone. These results suggest that long-term training enhances both testicular adrenal and responses to endurance exercise. The possible role of hormonal changes in the mobilization of energy substrates during exercise is discussed.

Adult↗
PubMed1985

[Acute altitude-induced edema of the lung].

High-altitude pulmonary edema has the following clinical features: it occurs in young healthy subjects exposed to altitudes usually above 3,000 m; it is favored by rapid ascent, exercise, cold, and sleep; it can give a deceptive clinical picture because of the patchy distribution of the edema. Hemodynamically, severe pulmonary arterial hypertension (PAH) occurs without increase in wedge pressure or left atrial pressure. Under treatment (rest, oxygen, diuretics), the condition rapidly improves. The physiopathological mechanism of this non-cardiogenic edema is complex and not yet fully defined: PAH essentially stems from hyperreactivity of the pulmonary circulation towards hypoxic arteriolar vasoconstriction, increase in pulmonary blood volume, and pulmonary microthrombosis. Postulated mechanisms involving mixed intra-alveolar edema with high pressure and increased permeability are based on transarterial leakage, over perfusion with endothelial injury, and an increase of permeability in relation to histamine and vasoactive polypeptides. Prevention relies, for a large part, on the identification of HAPE-prone subjects, slow ascent to high altitude, moderate physical activity, warm clothing, and prior administration of acetazolamide.

Acute Disease↗
PubMed1983

Human frontal sweat rate and lactate concentration during heat exposure and exercise.

Output (Qsweat) and lactate concentration ( [L]sweat) in frontal sweat and blood lactate concentration ( [L]blood) were monitored in three male volunteers: one sedentary (S), one fit (F), and one very fit (VF). Measurements were made under three sweating conditions: 1) heat exposure to infrared radiation (IR) at rest for 25 min at 45 degrees C; 2) bicycle exercise at constant relative maximal aerobic power (87 +/- 2% MAP) for 25 min (Cst EX) at 23 degrees C; and 3) bicycle exercise at increasing work loads (from 60-95% MAP) in four or five successive 5-min steps (Incr EX) at 23 degrees C. Comparison of these data showed that under the above three conditions 1) Qsweat of S was lower than that of F and VF; and 2) changes in [L]sweat were different: in IR and Cst EX, [L]blood remained constant, and [L]sweat decreased with heat load duration similarly in the three subjects (the slopes of the two curves were not significantly different); at Incr Ex, [L]blood increased and [L]sweat remained constant in S, F, and VF (21.71 +/- 0.85, 16.75 +/- 0.99, 12.83 +/- 0.45 (SE) mM, respectively). It was suggested that the high [L]blood and increased adrenergic stimulation observed in Incr Ex could act on [L]sweat in relation to the physical fitness level.

Adult↗
PubMed1981

Time course of plasma growth hormone during exercise in humans at altitude.

The effects of hypoxia on growth hormone release during submaximal exercise were studied 1) in eight highlanders (HL) at 3,800 m (La Paz, Bolivia); and 2) in five lowlanders (LL) at sea level, after 5 days' sojourn at 2,850 m, and while breathing a hypoxic gas mixture (FIO2 - 0.15 corresponding to PIO2 at 2,850 m) 1 mo after returning to sea level. Concentrations of immunoreactive human growth hormone ([IRHGH]), blood glucose ([G]), free fatty acids ([FFA]), and lactate ([LA]) were determined repeatedly at rest, during 1 h of exercise, and after 1 h of recovery. Compared with LL, in HL, the resting value of [IRHGH] is higher, the rate of increase at the beginning of exercise is faster and earlier, but the mean maximal value reached at the end of exercise is similar. The response pattern in LL during the early stages of exposure to hypoxia resembles that of HL. No correlation was found between peak values of [IRHGH] and maximal values of [LA] and [FFA] or minimal values of [G]. The possible causes of the different time sequence observed in growth hormone dynamics during hypoxia are suggested: an alteration of the clearance of the hormone through a more pronounced reduction of hepatic blood flow or a difference in the state of the pituitary gland before the exercise begins. The study emphasizes the importance of characterizing time sequence of [IRHGH] by parameters other than the maximal value, e.g., by mean concentration computed over exercise period.

Acclimatization↗
PubMed1979

[Effects of hypoxia on the coronary circulation and myocardial metabolism].

The effects of hypoxia on coronary flow (Qcor) and myocardial metabolism differ according to whether the situation is acute, and transient, or chronic and prolonged (chronic hypoxia at high altitudes). Acute hypoxia induces a marked increase in Qcor which is associated, in the case of severe hypoxia, with the production of lactate and pyruvate in the coronary venous blood, indicating abnormal aerobic metabolism of the myocardium, blocked by the lack of oxygen. A study of the effects of chronic hypoxia at high altitudes (HA) carried out at 3700 metres in 17 normal subjects revealed a significant decrease (of 24 to 28 per cent) in Qcor in comparison with a group of 12 normal subjects studied at sea level, using the same method (method of KETY-SCHMIDT with N2O and tritiated water method). The finding at HA of a decrease in myocardial oxygen consumption for a given external cardiac work load in comparison with the sea level group would suggest an increase in left ventricular work yield. Associated with other favourable changes in the myocardium (increase in terminal and capillary circulation, quantitative and qualitative improvement in the respiratory enzyme chain) the apparently beneficial effects of chronic hypoxia at HA may be suggested as a means for the prevention of coronary disease.

Coronary Circulation↗
PubMed1979

[Research of keratinophiles in the soil and their effects on human cutaneous pathology in the Lyons area].

Between 1967 and 1977, the systematic research of keratinophiles of the ground in a radius of 30--50 km around Lyon, has shown the ubiquitarian predominance of Microsporum nanum, which is probably the most ancient occupant of the ground. The most intensive areas of human and animal occupation in the Rhodanian tract show the predominance of Microsporum gypseum, which is scarcely found in man. Sporadic localizations, tightly limites, bound to cirulcation axes and international gathering, let us detect Microsporum cookei, Trichophyton verrucosum, Trichophyton mentagrophytes, Chrysosporium keratinophilum, and Keratinomyces ajelloi. However, in the last years, a progressive extension of recently imported kinds and a decrease in native kinds appears to have occurred.

Dermatomycoses↗
PubMed1977

Uptake of noradrenaline in high altitude native's heart.

Uptake of 3H-noradrenaline by the heart was studied with sections of isolated atria obtained from high or lowlanders. In native highlanders, affinity for 3H-noradrenaline by human atria is more significant than in lowlanders. Furthermore, the Michaelis Menten constant is lower in high altitude native's heart.

Adaptation, Physiological↗
PubMed1977

[Changes in the affinity of oxygen for hemoglobin during general anesthesia].

The well known effects of the lowering of the intraerythrocyte 2, 3, diphosphoglycerate (2, 3, DPG) level and hypothermia, on the affinity of oxygen for hemoglobin, lead the authors to study the influence of these parameters on this affinity during general anesthesia. The following observations were made in 15 adult subjects, undergoing prolonged general anaesthesia (average time: 3 hrs. 10 minutes): the dissociation curve of oxyhemoglobin (DCO) by the method of mixing, the intraerythrocyte 2,3, DPG level, the hemoglobin concentration and arterial blood parameters (PO2, PCO2, pH). These measurements were recorded before and after the general anaesthesia. The results were the following: a significant reduction of P50, measured under standard conditions (from 27.64 +/- 1.74 torr to 25.57 +/- 2.28, p less than or equal to 0.01) associated with a decrease in 2,3, DPG (from 0.94 +/- 0.31 mol/mol Hb at 0.64 +/- 0.24 p less than 0.01). Among the factors responsible for this variation in the affinity, it was proved that the volume of blood transfused was of importance as well as a decrease in body temperature during the operation. When the temperature is made to vary from 37 degrees C to 35 degrees C. the P50 ranges from 25.57 +/- 2.28 to 22.86 +/- 0.97 (p less than 0.01). To conclude the authors underline the importance of hypothermia and the volume of blood transfused (average time of preservation = 15 days) on the effects of the affinity of oxygen for hemoglobin.

Adult↗