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Biomedical subjects

J Mercier

Publications and source records attributed to J Mercier.

At least 19 recordsLinked to original sources
PubMed1995

Aerobic and anaerobic contribution to Wingate test performance in sprint and middle-distance runners.

We investigated the aerobic and anaerobic contributions to performance during the Wingate test in sprint and middle-distance runners and whether they were related to the peak aerobic and anaerobic performances determined by two commonly used tests: the force-velocity test and an incremental aerobic exercise test. A group of 14 male competitive runners participated: 7 sprinters, aged 20.7 (SEM 1.3) years, competing in 50, 100 and 200-m events and 7 middle-distance runners, aged 20.0 (SEM 1.0) years, competing in 800, 1,000 and 1,500 m-events. The oxygen uptake (VO2) was recorded breath-by-breath during the test (30 s) and during the first 20 s of recovery. Blood samples for venous plasma lactate concentrations were drawn at rest before the start of the test and during the 20-min recovery period. During the Wingate test mean power (W) was determined and three values of mechanical efficiency, one individual and two arbitrary, 16% and 25%, were used to calculate the contributions of work by aerobic (Waer,ind,16%,25%) and anaerobic (Wan,ind,16%,25%) processes. Peak anaerobic power (Wan,peak) was estimated by the force-velocity test and maximal aerobic energy expenditure (Waer,peak) was determined during an incremental aerobic exercise test. During the Wingate test, the middle-distance runners had a significantly greater VO2 than the sprinters (P < 0.001), who had significantly greater venous plasma lactate concentrations (P < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

Exercise intolerance in patients with chronic heart failure: role of pulmonary diffusing limitation.

In order to test the hypothesis of pulmonary diffusing capacity involvement in exercise limitation in subjects with chronic heart failure (CHF), lung transfer factor (TLCO), oxygen saturation (SaO2), cardiac output (CO) and gas exchange were studied over the course of an incremental exercise test in 10 patients and 10 controls. The TLCO and transfer coefficient for carbon monoxide (TLCO/VA) were measured at rest and during recovery by the single breath method. The SaO2 was followed non-invasively with a finger oximeter and CO was determined according to the carbon dioxide rebreathing method. Analysis of respiratory variables at maximal effort showed significantly lower values in patients with CHF as regards peak oxygen uptake (VO2), minute ventilation (VE), heart rate (HR), oxygen pulse (O2 pulse), and CO with higher ventilatory reserve (VR) than controls. At a comparable workload (30 W), patients with CHF demonstrated higher values for VE and lower values for CO than controls. The TLCO, expressed as percent of predicted values, was significantly lower in CHF patients than controls, respectively, at rest (90.5 +/- 3.75% vs 106.8 +/- 3.8%) and within 5 min after maximal exercise (87 +/- 4.4% vs 117.4 +/- 3.81%). The TLCO/VA showed comparable data between the two groups at rest (81.7 +/- 3.28 vs 90.3 +/- 2.86%). However, significantly lower values of TLCO/VA were obtained for CHF after maximal exercise in comparison to control subjects (77.5 +/- 3.85% vs 96.3 +/- 3.95%). These results confirm the alteration of the main variables in relation to cardiopulmonary exercise limitation in-tHF, and indicate a significant decrease in TLCO and TLCO/VA after maximal exercise.(ABSTRACT TRUNCATED AT 250 WORDS)

Exercise↗
PubMed1995

[Standard radiography of the mandibular condyle in the dental office. The modified Parma and the Zimmer trans-orbital production technic using a retro-alveolar radiologic unit].

Trauma to the condylar area is rather frequent and the stomatologist should be capable of performing a standard radiographic exploration. Two incidences performed in the stomatologist's office using a dental tube appear to be essential. The modified Parma and the transorbitary Zimmer incidences are needed for lateral and anteroposterior views respectively. The equipment required for these views are described together with several examples.

Female↗
PubMed1995

[Orthognathic surgery with missing teeth].

Orthognathic surgery in patients with missing teeth can be divided into two categories. In the first case after tooth loss, specially designed bridging is required using the prosthesis already in place. In the second case in patients with congenital deficiencies, usually sequellae of cleft palate, there is a wider range of therapeutic options which are discussed on the basis of observed cases.

Anodontia↗
PubMed1995

[Maxillofacial manifestations of Steinert's myotonic dystrophy. Clinical and therapeutic aspects].

The craniofacial manifestations, together with teleradiographic and cephalometric findings, of Steinert's dystrophy were examined based on a review of the literature and the clinical features of several patients with myotonic dystrophy leading to the diagnosis of Steinert's disease. The prevalence of the functional impairments due to facial deformation varies with the severity of the disease, suggesting early interceptive treatment supported by orthopaedic care and rehabilitation therapy of orofacial functions. Surgery involves bimaxillary osteotomy which can improve mastication and facial morphology. Operative risks should be carefully identified with adequate explorations before surgery.

Adolescent↗
PubMed1994

Energy expenditure and cardiorespiratory responses at the transition between walking and running.

We investigated whether the spontaneous transition between walking and running during moving with increasing speed corresponds to the speed at which walking becomes less economical than running. Seven active male subjects [mean age, 23.7 (SEM 0.7) years, mean maximal oxygen uptake (VO2max), 57.5 (SEM 3.3) ml.kg-1.min-1, mean ventilatory threshold (VTh), 37.5 (SEM3) ml.kg-1.min-1] participated in this study. Each subject performed four exercise tests separated by 1-week intervals: test 1, VO2max and VTh were determined; test 2, the speed at which the transition between walking and running spontaneously occurs (ST) during increasing speed (increases of 0.5 km.h-1 every 4 min from 5 km.h-1) was determined; test 3, the subjects were constrained to walk for 4 min at ST, at ST +/- 0.5 km.h-1 and at ST +/- 1 km.h-1; and test 4, the subjects were constrained to run for 4 min at ST, at ST +/- 0.5 km.h-1 and at ST +/- 1 km.h-1. During exercise oxygen uptake (VO2), heart rate (HR), ventilation (VE), ventilatory equivalents for oxygen and carbon dioxide (VE/VO2, VE/VCO2), respiratory exchange ratio (R), stride length (SL), and stride frequency (SF) were measured.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Cardiopulmonary exercise testing. Determinants of dyspnea due to cardiac or pulmonary limitation.

The aim of this study was to bring to light new and simple criteria, obtained during cardiopulmonary exercise testing, in order to demonstrate in patients the cardiac or the pulmonary origin of a comparable exertional dyspnea. Forty male subjects were compared, who exercised with a 30-W/3-min protocol and were divided into three groups: the cardiac heart failure (CHF) group (n = 15), the chronic obstructive lung disease (COLD) group (n = 15), and the control group (n = 10). The two groups of patients differed totally from the control group concerning their spirometric values at rest and a clear inability during effort which was confirmed by all the studied cardiopulmonary parameters at maximal exercise. The CHF and COLD groups differed slightly concerning their maximum symptom-limited oxygen uptake, only when related to body mass (13.26 +/- 0.69 ml/kg/min in CHF group, 17.05 +/- 1.59 ml/kg/min in COLD group; p < 0.05), and concerning their maximum ventilatory equivalent for oxygen which tended to be higher in the CHF group in comparison with the COLD group (p = 0.082). Furthermore, and as foreseen, the two groups of patients clearly differed at maximum exercise concerning the ventilatory reserve respiratory parameter (49.73 +/- 3.18 percent in CHF group, 8.38 +/- 5.85 percent in COLD group; p < 0.01). On the other hand, they did not differ concerning cardiac parameters or those considered as such (maximum heart rate [HR], HR reserve, HR response, maximum O2 pulse measurement). While their maximum ventilation was similar in the CHF and COLD groups, a difference in adaptation during exercise was found by observing their breathing pattern. In the CHF group, this was demonstrated by a significantly lower breathing frequency at maximum exercise (31.24 +/- 1.53 beats/min vs 37.75 +/- 2.24 beats/min; p < 0.05) and a tidal volume that tended to be higher at maximum exercise (p = 0.077) and significantly higher at 60-W work load (p < 0.05). This work shows that the study of ventilatory reserve and breathing pattern during exercise testing allows one to discriminate if dyspnea on exertion in patients is due to cardiac or respiratory disease.

Adult↗
PubMed1992

Age and training effects on the lactate kinetics of master athletes during maximal exercise.

To study the effects of age and training on lactate production in older trained subjects, the lactate kinetics of highly trained cyclists [HT, n = 7; 65 (SEM 1.2) years] and control subjects with low training (LT, n = 7) and of similar age were compared to those of young athletes [YA, n = 7; 26 (SEM 0.7) years], during an incremental exercise test to maximum power. The results showed that the lactacidaemia at maximal oxygen uptake (VO2max) was lower for HT than for LT (P < 0.05) and, in both cases, lower than that of YA (P < 0.001). The respective values were HT: 3.9 (SEM 0.51), LT: 5.36 (SEM 1.12), and YA: 10.3 (SEM 0.63) mmol.l-1. At submaximal powers, however, the difference in lactacidaemia was not significant between HT and YA, although the values for lactacidaemia at VO2max calculated per watt and per watt normalized by body mass were significantly lower for HT (P < 0.001) and LT (P < 0.02). These results would indicate that the decline in power with age induced a decline in lactacidaemia. Yet this loss in power was not the only causative factor; indeed, our results indicated a complementary metabolic influence. In the older subjects training decreased significantly the lactacidaemia for the same submaximal power (P < 0.01) and from 60% of VO2max onwards (P < 0.05); as for YA it postponed the increase and accumulation of lactates. The lactate increase threshold (Thla-,1) was found at 46% VO2max for LT and at 56% VO2max for HT.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Breathing pattern and ventilatory response to CO2 during exercise.

The aim of this study was to determine during moderate exercise whether response to the CO2 rebreathing test was dependent on differences in breathing pattern components among individuals recorded before the test and whether differences in tidal volume response and/or breathing frequency response to CO2 during the test could influence their ventilatory response to CO2. Ten healthy, sedentary male subjects, 20 to 34 years old, participated in the study. Ventilatory response to CO2 was measured by the CO2 rebreathing method (7% CO2, 50% O2). The measurements of breathing pattern components and CO2 rebreathing were made during mild steady state exercise: VCO2 = 20 ml.kg-1.min-1. We measured the following: 1) tidal volume (VTex) and breathing frequency (fex) before CO2 rebreathing and 2) ventilatory response to CO2 (SVEex), tidal volume response to CO2 (SVTex), and breathing frequency response to CO2 (Sfex) during the CO2 rebreathing test. The results showed that SVEex was correlated with VTex (r = 0.89, p less than 0.001), fex (r = -0.79, p less than 0.01), and Sfex (r = 0.83, p less than 0.01). There was no correlation between SVEex and SVTex. A curvilinear relationship existed between SVEex and alveolar ventilation calculated during exercise (r = 0.87, p less than 0.001), but there was no correlation with dead space. Sfex was positively correlated with VTex (r = 0.68, p less than 0.05) and negatively with fex (r = -0.70, p less than 0.05). We concluded that, during moderate exercise, higher tidal volumes measured before CO2 rebreathing were associated with higher response to the CO2 rebreathing test and consequently with higher ventilatory response to CO2.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Maximal anaerobic power: relationship to anthropometric characteristics during growth.

The purpose of this study was to determine the effects of age in relation to anthropometric characteristics upon maximal anaerobic power of legs in sixty-nine young boys aged 11 to 19 years. Maximal anaerobic power (Wmax) was measured by the force-velocity test. Lean body mass (LBM) was determined from all four skin-fold thickness measurements, leg volume (LV) was estimated by anthropometric method, and anthropometric measurements were used to determine total muscular mass (TMM). Wmax increased significantly (F = 44.1, p less than 0.001) between 11 and 19 years and was correlated with LV (r = 0.84) and TMM (r = 0.88). It was most highly correlated with LBM (r = 0.94), which best explained the percentage of the total variance of Wmax (88%). Normalized Wmax (Wmax/LBM) also increased significantly between 11 and 19 years (F = 21.9, p less than 0.001). In conclusion, Wmax determined by the force-velocity test was closely related to anthropometric characteristics, especially LBM, during the growth period. Furthermore, even when corrected for lean body mass, maximal anaerobic power was always found to increase. This suggests that other undetermined factors, in addition to the amount of lean tissue mass, may explain the increase of Wmax during the force-velocity test.

Adolescent↗
PubMed1992

[Biopsy of the salivary glands. The importance and technic of biopsy of the sublingual gland on its anterio-lateral side].

A new method of taking a sublingual gland sample is suggested by the authors in the fore pole. They emphasize on this straightforward operating act and on the amount of tissue removed. The aim of the removal could be etiologic within the framework of the Gougerot-Sjögren's syndrome, diagnostic in the sarcoidosis and rheumatoid arthritis, prognostic in the graft versus host disease.

Biopsy↗
PubMed1992

[Relation between the change of slope of heart rate and second lactic and ventilatory thresholds in muscular exercise with large load].

The time-course of heart rate, blood lactate, and ventilatory gas exchange was studied during an incremental exercise test on cycloergometer in order to ascertain whether heart rate deflection occurred at the same load as the second lactate S[La]2) and ventilatory (SV2) thresholds. Twelve moderately trained subjects, 22 to 30 years old, participated in the study. The initial power setting was 30 W for 3 min with successive increases of 30 W every min except at the end of the test where the increase was reduced to 20 and 10 W.min-1. Ventilatory flow (VE), oxygen uptake (VO2), carbon dioxide production (VCO2, ventilatory equivalents of O2 (EO2 = VE/VO2) and CO2 (ECO2 = VE/VCO2), and heart rate (HR) were determined during the last 20 s of every min. Venous blood samples were drawn at the end of each stage of effort and analyzed enzymatically for lactate concentration ([La]). The HR deflection, S[La]2, and SV2 were represented graphically by two investigators using a double blind procedure. Following the method proposed by Conconi et al. 1982, the deflection in HR was considered to begin at the point beyond which the increase in work intensity exceeded the increase in HR and the linearity of the work rate/HR relationship was lost. S[La]2 corresponded to the second breaking point of the lactate time-course curve (onset of blood lactate accumulation) and SV2 was identified at the second breaking point in the increase in VE and ventilatory equivalent for O2 uptake accompanied by a concomitant increase in ventilatory equivalent for CO2 output. We observed that the deflection point in HR was present only in 7 subjects. The work load, VO2, HR, and [La] levels at which heart rate departed from linearity did not differ significantly from those determined with S[La]2 ans SV2. The VO2 and HR values at HR deflection point were significantly correlated with those measured at S[La]2 and SV2. It is concluded that deflection in heart rate does not always occur, and when it does, it coincides with the second lactate and ventilatory gas exchange thresholds. It can thus be used for the determination of optimal intensity for individualized aerobic training.

Adult↗
PubMed1991

[Morphological accidents other than labio-maxillary clefts].

In neonates and infants facial and/or craniofacial involvement occurs in a large number of malformative syndromes the pathogenesis of which is obscure in most cases. This, added to clinical polymorphism, hinders all attempts at classification. However, chromosomal aberrations, as demonstrated by karyotype analysis, can be distinguished from other congenital conditions where the predominant site of the anomaly may help clinicians in their research. Thus, among congenital syndromes of probable genetic origin, the author studies those that are most frequent or most characteristic, i.e. craniostenosis (or craniofaciostenosis) with its neurocerebral risk; lesions that are predominant in the upper part of the face (osteochondrodysplasia, systematized neurocristopathies); lesions affecting mainly the lower part of the face (bilateral and unilateral mandibular lesions) and anomalies of the tongue. Among syndromes of epigenetic origin, only alcoholic embryofoetopathy is presented. Diagnosing such morphological accidents does not only suggest possible cranial and/or dentofacial therapeutic measures, sometimes applied at an early stage, but it also enables clinicians to inform, whenever possible, the parents on the potential genetic risk.

Child, Preschool↗
PubMed1991

Influence of anthropometric characteristics on changes in maximal exercise ventilation and breathing pattern during growth in boys.

The aim of this study was to investigate the effect of growth on ventilation and breathing pattern during maximal exercise oxygen consumption (VO2max) and their relationships with anthropometric characteristics. Seventy six untrained schoolboys, aged 10.5-15.5 years, participated in this study. Anthropometric measurements made included body mass, height, armspan, lean body mass, and body surface area. During an incremental exercise test, maximal ventilation (VEmax), tidal volume (VTmax), breathing frequency (fmax), inspiratory and expiratory times (tImax and tEmax), total duration of respiratory cycle (tTOTmax), mean inspiratory flow (VT/tImax), and inspiration fraction (tI/tTOTmax) were measured at VO2max. A power function was calculated between anthropometric characteristics and ventilatory variables to determine the allometric constants. The results showed firstly, that VEmax, VTmax, tImax, tEmax, tTOTmax, and VT/tImax increased with age and anthropometric characteristics (P less than 0.001), fmax decreased (P less than 0.001), and tI/tTOTmax remained constant during growth; secondly that lean body mass explained the greatest percentage of variance of VEmax (62.1%), VTmax (76.8%), and VT/tImax (70.6%), while anthropometric characteristics explained a slight percentage of variance of fmax and timing; and thirdly that VEmax, VTmax, and VT/tImax normalized by lean body mass did not change significantly with age. We concluded that at VO2max there were marked changes in ventilation and breathing pattern with growth. The changes in VEmax, VTmax, and VT/tImax were strongly related to the changes in lean body mass.

Adolescent↗
PubMed1991

Blood lactate increase during the force velocity exercise test.

Venous blood lactate concentration was measured during the force velocity exercise test in order to determine whether this test is strictly alactic or whether it draws upon lactic anaerobic metabolism. Nine trained male subjects, aged from 23 to 29 years, participated in this study. Two blood samples were drawn at rest, and then for each work load (1 kg to 10 kg): at the end of each sprint (S1) and at the 5th minute of recovery (S2). From the first braking force, venous blood lactate concentration increased very significantly during the force velocity test (p less than 0.001) and, once the peak of power has been obtained, the venous blood lactate concentration remained steady. The lactate increase for each load (delta[LA]) decreased significantly (p less than 0.01). From the beginning of the exercise to the peak of power, a significant positive correlation between the increase of power and the increase of blood lactate concentration measured at S2 existed (r = 0.71, p less than 0.001), whereas there was a negative correlation between the decrease of delta[LA] and the increase of power (r = -0.45, p less than 0.01). In conclusion, the repetition of sprints during the force velocity test induced a recruitment of lactic anaerobic metabolism. Maximal power must be considered as an alactic and lactic anaerobic power. The consequences of lactate accumulation in muscle may be a limitation of the maximal anaerobic power.

Acceleration↗
PubMed1991

Effect of resistive loads on pattern of respiratory muscle recruitment during exercise.

In healthy subjects, we compared the effects of an expiratory (ERL) and an inspiratory (IRL) resistive load (6 cmH2O.l-1.s) with no added resistive load on the pattern of respiratory muscle recruitment during exercise. Fifteen male subjects performed three exercise tests at 40% of maximum O2 uptake: 1) with no-added-resistive load (control), 2) with ERL, and 3) with IRL. In all subjects, we measured breathing pattern and mouth occlusion pressure (P0.1) from the 3rd min of exercise, in 10 subjects O2 uptake (VO2), CO2 output (VCO2), and respiratory exchange ratio (R), and in 5 subjects we measured gastric (Pga), pleural (Ppl), and transdiaphragmatic (Pdi) pressures. Both ERL and IRL induced a high increase of P0.1 and a decrease of minute ventilation. ERL induced a prolongation of expiratory time with a reduction of inspiratory time (TI), mean expiratory flow, and ratio of inspiratory to total time of the respiratory cycle (TI/TT). IRL induced a prolongation of TI with a decrease of mean inspiratory flow and an increase of tidal volume and TI/TT. With ERL, in two subjects, Pga increased and Ppl decreased more during inspiration than during control suggesting that the diaphragm was the most active muscle. In one subject, the increases of Ppl and Pga were weak; thus Pdi increased very little. In the two other subjects, Ppl decreased more during inspiration but Pga also decreased, leading to a decrease of Pdi. This suggests a recruitment of abdominal muscles during expiration and of accessory and intercostal muscles during inspiration. With IRL, in all subjects, Ppl again decreased more, Pga began to decrease until 40% of TI and then increased.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗