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Biomedical subjects

M Audran

Publications and source records attributed to M Audran.

At least 19 recordsLinked to original sources

Benefits of caffeine ingestion on sprint performance in trained and untrained swimmers.

The influence of specific training on benefits from caffeine (Caf) ingestion was examined during a sprint test in a group of highly trained swimmers (T) and compared with the response of a group of untrained occasional swimmers (UT). Seven T and seven UT subjects swam freestyle two randomly assigned 2 x 100 m distances, at maximal speed and separated by 20 min of passive recovery, once after Caf (250 mg) and once after placebo (Pla) ingestion. Anaerobic capacity was assessed by the mean velocity (meters per second) during each 100 m and blood was sampled from the fingertip just before and 1, 3, 5, 7, and 9 min after each 100 m for resting and maximal blood lactate concentration ([la-]b,max) determination. The [la-]bmax was significantly enhanced by Caf in both T and UT subjects (P less than 0.01). However, only T subjects exhibited significant improvement in their swimming velocity (P less than 0.01) after Caf or any significant impairment during the second 100 m. In light of these results, it appears that specific training is necessary to benefit from the metabolic adaptations induced by Caf during supramaximal exercise requiring a high anaerobic capacity.

Adolescent

[Investigation of phosphorus calcium metabolism after oral phosphorus supplementation].

Effects of oral administration of phosphorus on phosphorus and calcium parameters and on bone metabolism hormones were investigated in two studies: in the first, 12 young female adults and 8 females over 50 years of age took a single oral load dose of 780 mg elemental phosphorus, whereas in the second study assays were performed 5 and 15 days after initiation of twice-daily phosphorus supplements in 19 young adults, 14 subjects above 50 years of age who were free of osteoporosis, and 12 patients with osteoporosis also over 50 years of age. The phosphorus load was associated with an increase in intact parathyroid hormone levels (iPTH 1-84), which was more marked in subjects above 50 years of age than in younger adults. On the 15th day of phosphorus supplementation, there was no significant increase in baseline iPTH and no change in baseline dihydroxyvitamin D or osteocalcin levels; during the Nordin tests, the fractional calcium excretion index (CaU/CrU) and the fractional hydroxyproline excretion index (OH Pro/CrU) remained unchanged. In contrast, the phosphorus load was followed by a decrease in the maximum phosphorus reabsorption threshold (TMP/DFG), which was more marked on the 5th day than on the 15th day; a slight fall in serum phosphorus levels was also seen on the 15th day. These findings suggest that phosphorus supplementation should be intermittent rather than continuous. Analysis of subjects aged 50 to 69 years failed to disclose any significant differences between patients with and without osteoporosis.

Administration, Oral

[Bone density in idiopathic hypercalciuria in men. Study by dual photon absorptiometry, X-ray computed tomography and histomorphometry].

Lumbar bone mineral density (BMD) of the L3 vertebra was evaluated by double photon absorptiometry or tomodensitometry (TDM) in 55 hypercalciuric individuals in two separate studies. In the first, in a department of nephrology, 29 lithiasis patients were studied by TDM of L3. By this technique, trabecular density was 75 +/- 23% of normal. It was lower in the 17 patients in whom hypercalciuria persisted after calcium restriction (66 +/- 15% of normal and below the "fracture threshold" in 9 cases) than in the 12 patients in whom it disappeared after the prescription of such a diet (88 +/- 26%, below the "fracture threshold" in 3 cases), this difference being significant (p less than 0.01). In another 26 patients, seen in a department of rheumatology, three of whom had osteoporosis with vertebral fracture, density was measured in 21 cases by double photon absorptiometry (mean Z score -1.9 +/- 1.0) and in 5 cases by TDM (mean BMD of L3 69 +/- 21% of normal). Mean iliac trabecular volume, measured in 8 cases only, was 70 +/- 25% of normal and was below the "fracture threshold" in 3 cases. Comparison of the two study groups was not possible because of differences in recruitment and methods of investigation. These two studies nevertheless show the existence of significant vertebral bone rarefaction during hypercalciuria in the young man. Confirmed and quantified in patients in whom the metabolic disturbance was discovered as a result of radiological abnormalities, this quantitative abnormality was also seen in patients in whom hypercalciurie was found because of renal lithiasis.(ABSTRACT TRUNCATED AT 250 WORDS)

Absorptiometry, Photon

[Study of bone repercussion in 33 cases with anorexia nervosa which 8 with fracture osteoporosis].

A national survey has regrouped 33 cases of anorexia nervosa (AN) with osseous investigations, in particular an absorptiometry of the lumbar spine. 2 groups have been defined: 25 patients without fracture (F-) and 8 patients with osteoporotic fractures (F+), including 5 cases with 12 vertebral fractures and 5 with non vertebral fractures: 31/33 have a low lumbar bone mineral content (BMC). The lumbar BMC of the F+ is significantly lower than the F-: -4.1 +/- 1.6 DS versus -2.2 +/- 1.2 DS (p less than 0.001). 5 F+ patients are under the fracture threshold (FT), (O F-), 2 F+ are on the same level as the FT, and the last F+ has a lumbar BMC 15% above the FT, but an osteoporotic wrist fracture and a very low femoral neck BMC (0.64 g/m2, normal 1.06 +/- 0.15). F+ are older (35.2 year old versus 23.6, p less than 0.001), owing the fact that the duration of the AN (+ 9.2 years, p less than 0.005) and of the amenorrhea (+ 9.8 years, p less than 0.001) are longer, although the AN began at the same age in the 2 groups. The minimum weight, the body mass index, the percentage of loss of weight are similar in the 2 groups. Phosphocalcic biological studies, which show rather high osteocalcinemia and hydroxyprolinuria (hyperremodeling), with rather high serum 1-25 OH vitamin D, do not differ between the 2 groups. Endocrinologic evaluations, with a constant hypooestradiolemia of hypothalamic origin, low somatomedinemia and normal cortisolemia, are not different between the 2 groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Absorptiometry, Photon

[Bone involvement in primary oxalosis. Study of 20 cases].

The authors report 20 cases of primary oxalosis with bone involvement, late revealed in adults in 19 cases. They have studied the clinical, radiological and histological manifestations of this bone oxalosis. 19 cases had an end stage chronic renal failure, either treated by maintenance hemodialysis, or by renal (or liver-renal) graft. 17 patients complained of bone pain after starting hemodialysis; 3 had vertebral crush fractures, and 1 multiple spontaneous fractures. Diffuse bone sclerosis (with a homogeneous pattern on axial skeleton and a patchy appearance on the peripherical skeleton), bone translucency, subperiosteal phalangeal resorption were the main radiological symptoms. Oxalate crystals surrounded by a giant cells granuloma were always observed on bone biopsy (16 cases). Bone resorption was observed in 9 cases, hyperparathyroidism in 14 cases and osteomalacia in 7 cases. Hyperparathyroidism does'nt explain all the clinical and radiological manifestations (especially bone resorption). Bone resorption as other radiological and clinical manifestations can be found without hyperparathyroidism and can increase despite parathyroidectomy; so, bone resorption seems to be partly due to the granulomatous reaction around oxalate crystals rather than hyperparathyroidism.

Adolescent

[Bone density in 20 black African young adults of the Bantu race is identical to that in subjects of white race].

Bone mineral content (BMC in g) as well as bone mineral density (BMD in g/cm2) were measured by dual photon absorptiometry in 20 black africans and 20 white individuals of the same age and sex. The BMC of african males, as well as their body mass index (BMI), were significantly less than those of the whites. In contrast, neither BMD nor the ratio of BMC to BMI differed between the two groups. These results suggest that morphotype plays a greater role than the ethnic factor in the determination of bone mass in the young adult.

Adult

Effects of moderate exercise on the pharmacokinetics of caffeine.

The effect of moderate exercise on the kinetics of caffeine in 12 healthy volunteers-6 heavy coffee drinkers (HD) and 6 light coffee drinkers (LD) has been studied. Kinetics at Rest was measured first (R): the subjects remained at rest for 8 h after a single 250 mg dose of caffeine. One week later, the Exercise Kinetics (E) was measured under the same conditions, but with the subjects performing moderate exercise (30% of VO2 max) during the first hour of the study. Exercise raised the maximal plasma caffeine concentrations (R: 7.28: E: 10.45) and reduced both the half-life (R 3.99 h: E 2.29 h) and the volume of distribution (R 37 l: E 20.9 l). Both during exercise and at rest. HD had a greater half-life elimination and volume of distribution than LD. The results suggest potentiation of the effects of caffeine during exercise and an increase in its distribution due to regular heavy coffee intake.

Administration, Oral

Aminohydroxypropylidene bisphosphonate (AHPrBP) treatment of severe immobilization hypercalcaemia in a young patient.

We report a case of severe hypercalcaemia in a 16-year-old patient, 24 weeks after immobilization for quadriplegia. The biochemical and histomorphometric parameters showed increased osteoclastic resorption and decreased osteoblastic formation. Hydration, chair sitting, salmon and porcine calcitonin, sodium etidronate were unable to normalize the hypercalcaemia. The new antiosteoclastic agent, 3-amino-1 hydroxypropylidene-1, 1-bisphosphonate (AHPrBP), was effective in normalizing serum calcium and biochemical parameters of osteoclastic activity within five days. Bone histomorphometry showed a marked reduction in osteoclastic activity after AHPrBP treatment, as well as a drastic depression of osteoblastic activity, presumably due to the reduction of bone turnover. This case represents to our knowledge, the first successful use of AHPrBP in the treatment of immobilization hypercalcaemia.

Adolescent

Effects of caffeine ingestion on performance and anaerobic metabolism during the Wingate Test.

In order to determine the effects of caffeine ingestion on performance and metabolic responses during supramaximal exercise, six healthy volunteers performed the Wingate Anaerobic Test twice. Sixty min before each trial, while in a fasting state, they took capsules containing either caffeine (5 mg/kg) or a placebo, according to a single blind and randomized procedure. Caffeine administration did not significantly change either maximal anaerobic capacity (AC) or power (AP) and power decrease (PD). It did, however, induce significant (p less than 0.05) increases in both catecholamine and blood lactate levels as compared to values obtained after placebo administration. Moreover, maximal blood lactate occurred earlier (p less than 0.05), and lactate output seemed to be greater with caffeine (p less than 0.01). There was a strong correlation, both with and without caffeine, between epinephrine and lactate levels (r = 0.81) and between both AP and AC and lactate levels. These data suggest that caffeine, essentially via epinephrine, modifies glycolytic metabolism but fails to improve performance during the Wingate Anaerobic Test in nonspecifically trained subjects.

Adult

[Calcificated necrotic inflammatory granuloma after intradiscal injection of triamcinolone hexacetonide].

Recently, it has been demonstrated that symptomatic epidural calcifications represent a complication of intradiscal injection of triamcinolone hexacetonide (Hexatrione). Out of our three cases, pathological examination showed lesions of necrosis with granulomatous inflammatory reaction and bone metaplasia. Necrosis seems to be the primary cause of calcifications so we propose to call the lesion inflammatory and necrotic granuloma. The incidence of these granulomas is unknown. They are unpredictable and appear with a mean range of a year following the intradiscal injection. The treatment is surgery if they become symptomatic.

Anti-Inflammatory Agents

[Influence of brief high intensity exercise on plasma adrenaline and noradrenaline levels].

This study was conducted to determine catecholamine response to maximal intensity exercise of a few seconds' duration. To do this, epinephrine (E) and norepinephrine (NE) levels were measured during Force-Velocity Test. Blood samples were taken at the end of each sprint. Compared to rest (E0 = 77.4 +/- 3.8 pg/ml), the E concentration significantly increased after the first sprint (E2 = 109.8 +/- 14.7 pg/ml) and after the last one (E8 = 126.9 +/- 19.4 pg/ml) which correspond to the exhaustion state of our subjects. NE concentration doubled after the first sprint (NE2 = 589.1 +/- 94.7 pg/ml) and remained at this level until the end of the test. E2 seems to have been a stress reaction to an unfamiliar test. E8 may represent the "exercise plus exhaustion" stimulus on the stimulation of the adrenal gland (AG). This would suggest that stimulus intensity plays a role even when duration is very brief, although the time factor seems to limit the response of AG. The evolution of NE suggest that the brief duration of the sprints may limit the adatation response of NE to energy demands.

Adult

Concentration of bone elements in osteoporosis.

In aging and in osteoporosis, decreased bone density is associated with decreased bone mass. However, changes in the bone mineral phase remain a matter for investigation. In particular, it is unknown whether bone mineral loss is directly related to reduction in bone mass or associated with changes in the concentration of mineral elements in mineralized bone tissue. In this study, the cortical bone concentration of elements was determined in biopsies of the ilium from 33 subjects (12 controls and 21 individuals with untreated severe osteoporosis). Calcium and phosphorus concentrations were evaluated in cortical and trabecular bone using energy-dispersive x-ray (EDX) microanalysis and inductively coupled plasma optical emission spectrometry (ICPOES). Bone concentrations of Na, K, Mg, Cu, Zn, Fe, Sr, Al, B, and Si were also determined in cortical bone using ICPOES. Additionally, the concentration of F in cortical bone was measured with a specific ion electrode and the concentration of Pb was determined by atomic absorption spectrometry. In mineralized bone tissue there was no significant age-dependent variation in the concentration of Ca, P, or other elements either in controls or in osteoporotic subjects. Moreover, the concentration of elements in bone tissue did not differ in the two groups. These results suggest that the decrease in bone density in osteoporosis is directly related to evolution of the bone mass, without detectable changes in the concentration of elements in bone.

Adult

[Effect of acute or chronic administration of caffeine on performance and on catecholamines during maximal cycle ergometer exercise].

Seven men were studied during maximal cycle ergometer exercise, to assess the effects of a single or continuous caffeine ingestion on performance and catecholamine secretion. A single blind and randomised procedure was followed with three trials at 100 +/- 5% VO2 max until exhaustion. The first trial was performed after a single administration of 250 mg of caffeine (a). The second and third trials were performed after a treatment of 5 days with 250 mg caffeine per day (continuous = c) and after placebo (p). a and c caffeine administration, 60 min prior to exercise, did not significantly change the time to exhaustion, but increased the plasma levels of both epinephrine (E) and norepinephrine (NE) at exhaustion (p less than 0.05). Single ingestion of caffeine accelerated the elimination of E and NE and increased the maximal blood lactic acid. These data suggest that both single and continuous administration of caffeine do not enhance performance during maximal cycle ergometer exercise, but do increase the exercise response of catecholamine. Only a single administration modifies the blood lactate accumulation.

Adult

[The development of bone mass during a lifetime].

The authors present a reminder of the methods used to evaluate the bone mass and density and, with population studies, specify the profile and significance of the physiological osteopenia in both sexes. Analysis of these studies shows that the age of onset of the bone loss and its percentage vary markedly between the various sites of the skeleton, according to the type of bone, cortical or trabecular. It seems that the "smooth" aspect of the physiological osteopenia curves obtained is women during population studies, essentially results from the disparity between the times of menopause. A general protocol of the physiological osteopenia, synthesizing all data collected with nine different methods of measurement of the mineral bone content, is presented for educational purposes.

Adult