Biomedical subjects

J Dassonville

Publications and source records attributed to J Dassonville.

At least 19 recordsLinked to original sources

PubMed2005

[Interpreting carbon monoxide transfer coefficient: significance and difficulties].

INTRODUCTION: Interpreting measurements of carbon monoxide can be problematic. STATE OF THE ART: The transfer factor (TLCO) is usually calculated by multiplying the decrease in alveolar CO concentration between the beginning and the end of a 10 second breath hold (KCO) by the alveolar volume (VA). Thus a reduced TLCO may occur due to either a low KCO, a reduced VA, or a combination of both. PERSPECTIVES: A careful examination of KCO and VA will usually suggest a specific explanation for a reduction in TLCO. In restrictive lung diseases from extrapulmonary origin, TLCO is low but TLCO/VA [[/INF 120% of the reference values. In interstitial lung disease, the value of TLCO/VA depends on whether the loss of lung units is diffuse or not, and probably also on the status of the microcirculation. In airflow obstruction, a low VA is caused by uneven distribution of inspired He/CO mixture within the breath-hold time. CONCLUSIONS: The transfer factor for carbon monoxide is best interpreted in terms of its components, alveolar volume and carbon monoxide transfer coefficient.

Carbon Monoxide↗

PubMed2004

[Diffusing capacity for carbon monoxide (T(LCO)) and oxygen saturation during exercise in patients with cystic fibrosis].

OBJECTIVES: To estimate the value of diffusing capacity for carbon monoxide (T(LCO)) in patients with cystic fibrosis and to evaluate its ability to predict arterial desaturation during exercise. METHOD: Fourty-four patients (9-30 years) with cystic fibrosis performed pulmonary function tests with measure of T(LCO) and a bicycle incremental exercise test. They represent a wide variation in disease severity: mean Shwachman score: 77.8 (range: 40-100), mean FEV1%: 72.8 (range: 17-131). This study investigated the relationship between T(LCO), lung volumes and exercise data. RESULTS: T(LCO) remained normal for a long time in patients with cystic fibrosis: 82% of them show a normal T(LCO) (mean value: 91.3% of predicted). T(LCO) was significantly correlated with FEV(1), residual volume, maximal work load and maximum oxygen uptake. A fall in arterial oxygen saturation was uncommon in our study (five patients) and not significantly correlated with T(LCO). CONCLUSIONS: T(LCO) is a good criter of severity of cystic fibrosis but remains unreliable to predict values above which physical activity is safe, without arterial desaturation. Exercise tests should be proposed in order to evaluate exercise adaptation of each patient and determine which factor limits maximal performance.

Adolescent↗

PubMed2002

[Exercise-induced laryngomalacia].

Exercise-induced laryngomalacia is a rare differential diagnosis of exercise-induced asthma. We report the case of a previously fit 14-year-old female patient who presented with dyspnoea on intense exertion and whose condition had not improved with treatment prescribed for a misdiagnosed exercise-induced asthma. A diagnosis of exercise-induced laryngomalacia was eventually made when a variable extra-thoracic airway obstruction on the flow-volume loops was obtained after an incremental exercise test. Flexible fiberoptic rhinolaryngoscopy confirmed this abnormality and demonstrated an anterior prolapse of the arytenoid region, partially obstructing the airway. The patient therefore underwent laser aryepiglottoplasty which produced a satisfactory anatomical outcome in the larynx but which only resulted in a partial functional improvement. Laryngomalacia is rare and its pathophysiology is not well understood. However, it should be considered in patients presenting with exertional dyspnoea, particularly if there is inspiratory embarrassment, who fail to improve with beta-2-adrenergic agonists. The diagnosis can be made from the flow-volume loop and direct laryngoscopy, before and after exercise.

Adolescent↗

PubMed2001

[Asthma and scuba diving Absolute contraindication? in all asthma patients?].

Physical and psychological fitness are required for scuba diving, leading to medical contraindications in certain subjects. Asthma, a condition exhibiting increasing prevalence in the general population is currently considered an absolute contraindication for scuba diving by the French Federation for Submarine Sports and Education (FFESSM). There is however no documented evidence demonstrating a higher risk in asthmatic divers. Our English-speaking colleagues have suggested that certain asthmatic subjects could participate in scuba diving sports under certain conditions without any higher risk compared with non-asthmatic divers. We recall here the impact of diving on respiratory function and potential consequences in asthmatic subjects, proposing that the formal contraindication against scuba diving should be maintained for asthmatic patients who experience frequent symptoms (step 2 or more of the International Consensus Report on Diagnosis and Treatment of Asthma) and/or have a baseline obstructive syndrome. It would appear reasonable to discuss the contraindication concerning patients with rare acute episodes and who have a perfectly normal respiratory function. The question of bronchodilator inhalation prior to diving may be a question to debate. However, such a proposal cannot be considered to be valid unless well-conducted studies of the clinical manifestations are available (frequency and severity of the acute episodes, triggering factors) for the diver candidate. Because of the highly restrictive nature of the contraindication notification and the absence of arguments backing up the decision, the question should be put to competent authorities (sports federations, learned societies) in order to ascertain the pathophysiological mechanisms involved and collect reliable epidemiological data before proposing a consensus discussion. This process may lead to the delivery of scuba diving authorizations for selected asthmatic subjects without a higher risk than non-asthmatic subjects.

Acute Disease↗

PubMed2000

Clinical experience with functional electrical stimulation-assisted gait with Parastep in spinal cord-injured patients.

STUDY DESIGN: Clinical evaluation of the Parastep method, a six-channel transcutaneous functional electrical stimulation device, in spinal cord-injured patients. OBJECTIVES: To investigate the motor performances of this new technique regarding energy expenditure and to evaluate its advantages and limitations, especially in social activities involving ambulation. METHODS: This study was conducted in 15 thoracic spine-injured patients. The lesion was complete except in two patients. The gait ability and the functional use were judged clinically. Energy cost was evaluated from heart rate, peak oxygen uptake, and lactatemia. RESULTS: Thirteen patients completed the training (mean: 20 sessions) and achieved independent ambulation with a walker. The mean walking distance, without rest, was 52.8 +/- 69 m, and the mean speed was 0.15 +/- 0.14 m/sec. One patient with incomplete lesion, who had been nonambulatory for 8 months after the injury, became able to walk without functional electrical stimulation after five sessions. The follow-up was 40 +/- 11 months. Five patients pursued using functional electrical stimulation-assisted gait as a means of physical exercise but not for ambulation in social activities. The patients experienced marked psychological benefits, with positive changes in their way of life. In three subjects, a comparison of physiologic responses to exercise between a progressive arm ergometer test and a walking test with the Parastep (Sigmedics, Inc., Northfield, IL) at a speed of 0.1 m/sec was performed, showing that the heart rate, the peak oxygen uptake, and lactatemia during gait were close to those obtained at the end of the maximal test on the ergometer. CONCLUSIONS: In spite of its ease of operation and good cosmetic acceptance, the Parastep approach has very limited applications for mobility in daily life, because of its modest performance associated with high metabolic cost and cardiovascular strain. However, it can be proposed as a resource to keep physical and psychological fitness in patients with spinal cord injury.

Adolescent↗

PubMed1998

Blood lactate concentrations during exercise: effect of sampling site and exercise mode.

BACKGROUND: The purpose of the study was to compare blood lactate concentrations determined in blood sampled from three sites (finger capillary, ear-lobe capillary, and forearm vein) during exercise on three different ergometers (a cycle ergometer, a treadmill and an arm-crank ergometer). METHODS: A total of 312 well-trained subjects performed either a six-minute steady-state exercise (n = 219) or an incremental exercise test until exhaustion (n = 93). Blood was sampled from two sites after each exercise test and at the end of each stage of the incremental protocol, 852 pairs of blood samples were analysed. RESULTS: Results showed that, when exercise was performed on a cycle ergometer or a treadmill, no significant differences between venous and ear capillary samples were observed whereas finger capillary values were higher. On an arm-crank ergometer, venous and finger capillary lactate concentrations were usually higher than ear capillary values with some discrepancies depending on the times of sampling. CONCLUSIONS: We conclude that lactate values may differ depending on the sampling site and the type of exercise mode. An ear capillary sample may be preferred because it is less affected by lactate release in the arms and easier to obtain.

Adolescent↗

PubMed1996

Energy consumption of paraplegic locomotion using reciprocating gait orthosis.

The energy cost of walking using a reciprocating gait orthosis (RGOII) with functional electrical stimulation (FES) was assessed in 14 patients with spastic complete paraplegia from six rehabilitation centres. Before and after training asing RGOII with FES, the subjects performed a progressive maximal test on an arm-crank ergometer to obtain their laboratory peak oxygen uptake (LVO2peak), heart rate (HR) and blood lactate concentration changes. At the end of the training session, oxygen uptake (VO2) was measured during a walking test with orthosis at different speeds (6 min steady state at 0.1 m.s-1, followed by 2-min stages at progressively increasing speeds up to exhaustion). Of the subjects 4 repeated this test using orthosis without FES. At a speed of 0.1 m.s-1, VO2 represented 47 (SD 23)% of LVO2peak, mean HR was 137 (SD 21) beats.min-1 and mean blood lactate concentration 2.4. (SD 1.4) mmol.l-1. Maximal speed ranged from 0.23 to 0.5 m.s-1. At maximal speed, VO2 was 91 (SD 18)% of LVO2peak, mean HR reached 96 (SD 7)% and mean blood lactate concentration only 52 (SD 19)% of the maximal values measured during the laboratory test. Walking without electrical stimulation induced an increase in HR but there was no difference in VO2 and blood lactate compared to walking with stimulation. The training period did not result in any improvement in maximal physiological data. We concluded that the free cadence walking speed with orthosis remains much lower than that of able-bodied people or wheelchair users. The metabolic cost at a given speed is much higher even if, using a stimulation device, the cardiovascular stress is reduced.

Adult↗

PubMed1996

Long-term nasal intermittent positive pressure ventilation (NIPPV) in sixteen consecutive patients with bronchiectasis: a retrospective study.

Life expectancy and quality of life are poor in patients with chronic respiratory failure due to bronchiectasis. The indication for nocturnal nasal intermittent positive pressure ventilation (NIPPV) remains controversial in chronic obstructive lung disease. The purpose of the present study was to determine whether some of the objectives of home mechanical ventilation, i.e. improvement in blood gas values and reduced length of hospitalization, were fulfilled by NIPPV and oxygen plus medical treatment in patients with chronic respiratory failure due to bronchiectasis. Sixteen consecutive patients (12 females and four males; mean age 57 +/- 11 yrs) with chronic respiratory failure due to bronchiectasis, treated at home with nocturnal NIPPV in addition to oxygen therapy, were retrospectively studied in terms of blood gas values and duration of hospitalization before and after NIPPV. Details of the therapy received by each patient were recorded. Nine patients agreed to complete a questionnaire to determine their perception of the benefits of the treatment. NIPPV was performed using a volumetric respirator and was applied with a customized nasal mask modelled with silicone paste. NIPPV was used for a mean of 26 months (range 0.5-60 months). Eleven patients were alive 12 months after use of NIPPV. No significant improvement in blood gas values was noted on room air during NIPPV, but arterial carbon dioxide tension (Pa,CO2) stabilized after the period of worsening observed before initiation of NIPPV. Duration of hospitalization, the year before and the year after NIPPV, was 19 (3-40) and 16 (8-37) days, respectively (NS). For the 11 patients who were alive 2 yrs after the start of NIPPV, duration of hospitalization the year before NIPPV and between 12 and 24 months after NIPPV were 17 (4-40) and 7 (2-27) days, respectively (p < 0.05). Nine patients who had received NIPPV for at least 12 months at the time of the study reported an improvement in their quality of life. The results suggest that home ventilatory support by nasal intermittent positive pressure ventilation offers an acceptable alternative to tracheotomy, with less discomfort, in the management of severe respiratory failure due to bronchiectasis, in order to allow the patient to return home. These results should be confirmed by controlled studies.

Adult↗

PubMed1995

Restoration of functional gait in paraplegic patients with the RGO-II hybrid orthosis. A multicenter controlled study. II: Physiological evaluation.

We have investigated physiological changes in 21 patients with a spinal cord injury who were fitted with the RGO-II hybrid orthosis. All parameters were measured before and after a training programme in order to evaluate the benefit of gait rehabilitation, cardiovascular adaptation, constipation, spasticity and osteoporosis. A tendency for the improvement in cardiovascular function was noticed, and a segmental decrease in right colonic transit time was observed. However there was no reproducible change in spasticity, and no gain in bone mineral density. These data suggest that the physiological benefits which occur when patients walk with the aid of a hybrid orthosis only correct the effects of immobility. In addition, we did not find any physiological improvement regarding the neurological lesion (spasticity or osteoporosis).

Adult↗

PubMed1994

Use of oxygen uptake recovery curve to predict peak oxygen uptake in upper body exercise.

A group of 18 well-trained white-water kayakers performed maximal upper body exercise in the laboratory and during a field test. Laboratory direct peak oxygen uptake (VO2) values were compared, firstly by a VO2 backward extrapolation estimation and secondly by an estimation calculated from VO2 measured during the first 20 s of exercise recovery. Direct peak VO2 correlated with VO2 backward extrapolation (r = 0.89), but the results of this study showed that the backward extrapolation method tended to overestimate significantly peak VO2 by [0.57 (SD 0.31) l.min-1 in the laboratory, and 0.66 (SD 0.33) l.min-1 in the field, P < 0.001]. The VO2 measured during the first 20 s of recovery, whether the exercise was performed in the laboratory or in the field, correlated well with the laboratory direct peak VO2 (r = 0.92 and r = 0.91, respectively). The use of the regression equation obtained from field data (VO2F20s), that is peak VO2 = 0.23 + 1.08 VO2F20s, gave an estimated peak VO2, the mean difference of which compared with direct peak VO2 was 0.22 (SD 0.13) l.min-1. In conclusion, we propose the use of a regression equation to estimate peak VO2 from a single sample of the gas expired during the first 20 s of recovery after maximal exercise involving the upper part of the body.

Adult↗

PubMed1993

Ventilatory response of prepubertal boys and adults to carbon dioxide at rest and during exercise.

The aim of this study was to determine whether the greater ventilation in children at rest and during exercise is related to a greater CO2 ventilatory response. The CO2 ventilatory response was measured in nine prepubertal boys [10.3 years (SD 0.1)] and in 10 adults [24.9 years (SD 0.8)] at rest and during moderate exercise (VCO2 = 20 ml.kg-1.min-1) using the CO2-rebreathing method. Three criteria were measured in all subjects to assess the ventilatory response to CO2: the CO2 sensitivity threshold (Th), which was defined as the value of end tidal PCO2 (PETCO2) where the ventilation increased above its steady-state level; the reactivity slope expressed per unit of body mass (SBM), which was the slope of the linear relation between minute ventilation (VE) and PETCO2 above Th; and the slope of the relationship between the quotient of tidal volume (VT) and inspiration time (tI) and PETCO2 (VT.tI-1.PETCO2(-1)) values above Th. The VE, VT, breathing frequency (fR), oxygen uptake (VO2), and CO2 production (VCO2) were also measured before the CO2-rebreathing test. The following results were obtained. First, children had greater ventilation per unit body weight than adults at rest (P < 0.001) and during exercise (P < 0.01). Second, at rest, only VT.tI-1.PETCO2(-1) was greater in children than in adults (P < 0.001). Third, during exercise, children had a higher SBM (P < 0.02) and VT.tI-1.PETCO2(-1) (P < 0.001) while Th was lower (P < 0.02).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1992

Effects of captopril chronic intake on the aerobic performance and muscle strength of normotensive trained subjects.

Fifteen normotensive athletes specializing in dynamic sports took part in a randomized double-blind and cross-over study: captopril (50 mg/24 h) vs placebo. Each treatment lasted one month. Maximal exercise tests on cycle ergometer were performed at the end of each period. No significant differences were observed in the maximal values of oxygen uptake, power, heart rate or blood lactate value. The anaerobic threshold, defined as the exercise intensity which corresponded to a 4 mmol.l-1 blood lactate level was unchanged. With captopril, the end-of-exercise systolic and diastolic BP were slightly altered (NS). Lower limb muscle strength, as explored with a Cybex isokinetic system, was not modified by captopril intake. The results indicate that maximal aerobic performance and isokinetic strength of the lower limbs are not altered by captopril chronic administration (50 mg/day) in normotensive trained subjects.

Adult↗

PubMed1992

[Comparative urinary elimination of caffeine in sedentary and sportsmen after administration of Guronsan].

The authors present the results of a study on urinary excretion of caffeine, after a single oral intake of 100 mg of caffeine, in two populations of students at rest and during exercise. Whether expressed in mg/l or mg/g creatinine no significant difference in urinary excretion of caffeine was observed between the two populations and it proves to be lower than the limit level authorized by the IOC (12 mg/l).

Adolescent↗

PubMed1991

Does peripheral blood T-lymphocyte population distribution in sarcoidosis provide a prognostic clue?

In its pulmonary form, sarcoidosis generally resolves spontaneously, but it may lead to fibrosis of the lung. The clinical, radiological and functional tests, as well as activity markers such as the serum angiotensin converting enzyme, intrathoracic uptake of 67Gallium and the cytological data provided by bronchoalveolar lavage are only the expressions at any given time of a disease which is constantly progressing and only partly express its evolutive potential. The authors studied the distribution of T-lymphocyte subsets in the peripheral blood and from bronchoalveolar lavage. 32 patients were included in the study. They were suffering from acute or chronic sarcoidosis of the mediastinum and lungs and were divided into 2 groups according to clinical, radiological and pulmonary function criteria; Group A (n = 19) included regressive forms (minimum follow up 2 years) and group B (n = 13) the progressive untreated forms. Lymphopenia with a decrease in the percentage of CD3 cells was found in both groups. The percentage of CD4 cells is significantly lower in group B (28 +/- 11%) than in group A (45 +/- 8%) (p < 0.01) or in the control population (46 +/- 8%) (p < 0.01). The percentage of CD8 cells is higher in group B (30 +/- 8%) than in group A (18 +/- 6%). This results in a CD4/CD8 ratio which is significantly reduced in group B (1 +/- 0.5) when compared with group A (2.72 +/- 0.8) (p < 0.01) and the control group (2.17 +/- 0.8) (p < 0.01), the difference between group A and the controls being minimal.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1988

Ventilatory and occlusion-pressure responses to exercise in trained and untrained children.

Pattern of breathing and mouth occlusion pressure were investigated during an incremental and exhaustive ergocycle test in untrained and trained 11 to 13 year old boys. At each level of exercise, the trained group had lower ventilation, a lower respiratory equivalent, and a lower respiratory rate. These results suggest that trained subjects have more efficient ventilation. Lower ventilation coincided with a smaller mean inspiratory flow (VT/TI), while the ratio of inspiratory to total breath (TI/TTOT) was unchanged. In contrast, mouth occlusion pressure and the index of neuromuscular inspiratory drive were the same up to 60 W for the two groups, and tended to be slightly lower in the trained boys above this level.

Adolescent↗

PubMed1988

Isokinetic investigation of knee extensors and knee flexors in young French soccer players.

The knee extensor and knee flexor muscle groups in three groups of young soccer players were tested with a Cybex II isokinetic dynamometer and compared with adults. Muscle strength increased with age. The largest gain was observed in young players aged 16-17 years whose quadriceps was the most modified muscle group giving the lowest H/Q ratio. Analysis of the regression equations obtained for torque values at 30 degrees s-1 and 180 degrees s-1 revealed that there were two distinct groups: under 16 and over 16. After reaching 16 years of age, the increase in muscle strength is greater at low velocity than at high velocity.

Adolescent↗

PubMed1988

[Idiopathic pulmonary hemosiderosis and rheumatoid arthritis. Apropos of a case].

A 38-year-old woman was known to have had a histologically proven "idiopathic" pulmonary hemosiderosis for 7 years; the authors report the onset in this patient of polyarthralgias with articular swelling and positivity of rheumatoid factor, all features consistent with the diagnosis of rheumatoid arthritis, whose beginning was certainly hidden by steroid therapy. This case, as some others previously published, outlines the possibility of the association of pulmonary hemosiderosis and rheumatoid arthritis: is this a casual association, or may pulmonary hemosiderosis be a rare manifestation of rheumatoid arthritis?

Adult↗

PubMed1987

Extent of lactic anaerobic metabolism in handballers.

The authors investigated lactic anaerobic metabolism in handball players during practice games. Seven players aged 18-21, belonging to second division league clubs, took part in the study. In the laboratory, VO2 max and the onset of blood lactate accumulation (OBLA) were determined with progressive maximal ergocycle tests. On the field, video recordings, cardiotelemetry, and rectal temperature measurements made during the first half of the game were used to quantify exertion. An intravenous catheter worn permanently was used to draw blood for lactate measurements at the 5th, 10th, 15th, 20th, and 30th min of play and after a 10-min rest period. The results confirmed earlier observations showing the need for an excellent maximal aerobic power and capacity in handballers. However, the maximal lactate levels observed (4-9 mmol X l-1) were above those that could be expected from samples drawn only at the end of play. These findings indicate that players must be trained to tolerate high lactate levels to preserve their maximal efficiency throughout the game. Finally, lactate production increased with player exertion and with increasing OBLA.

Adolescent↗