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Biomedical subjects

M Badier

Publications and source records attributed to M Badier.

At least 19 recordsLinked to original sources

Same efficacies of ipratropium and salbutamol in reversing methacholine-induced bronchoconstriction.

Efficacy of salbutamol (S) was compared to that of ipratropium (I) or to their association, after methacholine challenge testing (MCT). MCT was performed in 4 groups of 10 patients suspected to suffer from asthma; mean changes in FEV1, maximal midexpiratory flow rate (MMFR), and airway resistance (Raw) were the same in all groups. After MCT, the group 1 patients inhaled S and then I, 10 min later; both drugs were given in the reverse order to the group 2 patients. The group 3 patients inhaled a mixture of both drugs just after MCT; the group 4 patients were not given any bronchodilator till the 20th min after MCT, when they inhaled S. Short-term (10 min) bronchodilator effects of S, I or S + I on spirometric variables were of the same magnitude and Raw returned to its baseline value. Further improvement (10-20 min) in FEV1 was mainly due to spontaneous recovery, whereas further increase in MMFR was due also to bronchodilator actions of drugs. It is concluded that ipratropium could be proposed as an alternative bronchodilator to salbutamol after MCT.

Adult↗

[Shrinking lung syndrome and systemic auto-immune disease].

INTRODUCTION: Shrinking lung syndrome usually manifest in dyspnea, decreased lung volume associated with elevated diaphragm. It reports with systemic autoimmune disease and physiopathological mechanism is controversial. EXEGESIS: We report three shrinking lung syndrome observations in which two cases were diagnosed at the time to onset of autoimmune disease. The three patients were treated with corticosteroid, two of them necessitated theophylline. Review of the literature highlight 60 cases and permit to discuss physiopathological mechanisms which remain uncertain. Diaphragmatic dysfunction (because of myositis or neuropathy) represented by abnormal transdiaphragmatic pressures is actually discussed. CONCLUSION: Shrinking lung syndrome is rare but must be considered in patient with autoimmune disease and dyspnea. The diagnosis can be difficult because of clinical, pathological and functional features which are controversial. The optimum treatment is unknown.

Adult↗

Increased diaphragmatic strength and tolerance to fatigue after bilateral lung transplantation: an electromyographic study.

We evaluated the diaphragmatic function of seven patients with severe chronic respiratory failure before and after a bilateral lung transplantation (BLT), with follow-up at one year of pulmonary function tests, maximal inspiratory mouth pressure (MIP) and surface diaphragmatic electromyogram (Edi). The patients were asked to sustain target inspiratory pressures at -15, -30, and -50 cmH(2)O. We measured the endurance time (Tlim) to sustain inspiratory efforts and the power spectrum density function of Edi at each inspiratory maneuver. The Edi power spectra was analysed in terms of median frequency (MF), total power (TP) and energies in high-and low-frequency bands (EL and EH). Before BLT, a defect of the diaphragmatic function was evident: MIP was 62+/-7% of the predicted value and the Tlim measured at each inspiratory effort was very short ( 13+/-1 s, 10+/-1 s and 8+/-1 s at pressures of -15, -30, and -50 cmH(2)O, respectively). One month after BLT, the Tlim began to increase at all target inspiratory pressures and at 6 months MIP recovered to normal values. One month after BLT, there was a significant decrease in TP measured at the beginning of each inspiratory efforts and also an increase in the concomitant MF value. BLT markedly accentuated the maximal variations of TP, MF and low-frequency Edi energy. Some hypotheses are raised to explain this dramatic improvement in diaphragmatic function after BLT.

Adolescent↗

Electrostatic charge on spacer devices and salbutamol response in young children.

Electrostatic charge on plastic spacer devices may affect the efficacy of inhaled drugs, but its consequences have never been evaluated in asthmatic children with airflow limitation. At the end of a positive metacholine challenge, 64 children (51.3+/-12.9 months, 32 boys, specific airway resistance (SRaw) 257.1+/-56.7% and forced expiratory volume in 1s (FEV(1)) 64.2+/-17.9% of the predicted value) inhaled one puff of hydrofluoroalkane-134a (HFA-134a) salbutamol (Ventoline((R))), and 15min later two other puffs (total dose of 300 microgram), delivered through either a new static Babyhaler((R)) (n=21), a detergent-coated, reduced static, Babyhaler((R)) (n=20), or a metal NES-Spacer((R)) (n=23) equipped with facemask. SRaw and FEV(1) were measured after each treatment and compared between groups by a Kruskal-Wallis test. The first 100 microgram salbutamol induced a 151.7+/-43.9% decrease in SRaw and a 19.9+/-10.6% increase in FEV(1). Additional 200 microgram salbutamol allowed a supplementary decrease of 35.1+/-25.7% in SRaw and increase of 12.1+/-11.8% in FEV(1), without significant difference between the spacer devices. Electrostatic charge on spacer devices does not affect bronchodilation with HFA-134a salbutamol in metacholine-challenged pre-school children. This could be in part explained by the use of supramaximal doses of salbutamol.

Administration, Inhalation↗

Assessment of T lymphocyte cytokine production in induced sputum from asthmatics: a flow cytometry study.

BACKGROUND: Asthma results from a bronchial inflammation in which Th2 lymphocytes play a pivotal role, as shown in invasive bronchial biopsies and broncho-alveolar lavages. Induced sputum (IS) is a non-invasive method of recovery of bronchial cells, which can be repeated in the same patients. However, lymphocyte activation has not been studied in IS to date, because of the low number of T cells recovered. Herein we took advantage of flow cytometry, a method suitable for the study of small cell populations, to assess T cell cytokine production in IS. OBJECTIVES: (1) To assess induced sputum T cell cytokine production by flow cytometry in asthmatic subjects and controls. (2) To compare the T cell cytokine production between symptomatic and non-symptomatic asthmatics. METHODS: Thirteen asthmatics and 19 controls were included. Sputum was induced by a hypertonic saline. Sputum cells were stimulated and intracellular IL-13 and IFN-gamma were detected in T cells by flow cytometry. RESULTS: Stimulation induced an increase of IL-13 and IFN-gamma production by T cells. This increase was higher in asthmatics. IL-13-producing T cells were increased in asthmatics after stimulation. In symptomatic asthma, IFN-gamma-producing T cells were in higher proportion than in controlled asthma. CONCLUSION: IS T cell cytokine production indicates a basic Th2 bias in asthma, accompanied during symptoms by a Th1-like activation. These results open the field for longitudinal studies of the variation of T cell activation in asthma.

Adult↗

[Induced sputum as a new approach of the assessment of inflammation in asthma].

Asthma is an inflammatory condition. Traditionally bronchoalveolar lavage and bronchial biopsies obtained by bronchoscopy have been used to demonstrate inflammation. Induced-sputum is a non-invasive, reliable, reproducible and safer technique for monitoring inflammatory activity in patients with asthma. Studies have shown that induced-sputum measures aspects of inflammation distinct to that measured by bronchoalveolar lavage or bronchial biopsies. Numerous studies have suggested that induced-sputum is a potentially useful tool for early diagnosis of exacerbation, monitoring of therapy, identification of the lowest effective dose and assessing compliance in asthmatics. In this respect, we suggest that this test can be routinely used in the management of difficult asthmatics.

Asthma↗

Changes in maximal performance of inspiratory and skeletal muscles during and after the 7.1-MPa Hydra 10 record human dive.

During the 7.1-MPa hydrogen-helium-oxygen record human dive, we tested the hypothesis that the increased ambient pressure would alter the maximal muscle performance, specifically that breathing dense gas would lead to fatigue of the respiratory muscle. A group of hand muscles (adductor pollicis, AP) and the inspiratory muscles (IM) were studied in three professional divers. Maximal voluntary contractions (MVC) of AP and maximal inspiratory pressure (P(i(max))) generated by IM were measured prior to the dive, during compression and decompression, and then 1 and 2 months after the dive. The decrease in MVC (-22%) was significant at 3.1 MPa, i.e. at the beginning of the introduction of hydrogen into the breathing mixture, whereas P(i(max)) fell progressively during the dive and decompression (maximal DeltaP(i(max)) = -55%), a significant reduction still being measured 1 month after the dive. The altered IM function was attributed to the consequences of long-term ventilatory loading, a condition associated with breathing a dense gas. The transient decrease in MVC of the skeletal muscle would indicate a possible effect of the hyperbaric environment, possibly the high partial pressure of hydrogen, on neuromuscular drive.

Diving↗

Early detection of airway involvement in obliterative bronchiolitis after lung transplantation. Functional and bronchoalveolar lavage cell findings.

As defined by the International Society for Heart and Lung Transplantation, the diagnosis of posttransplant obliterative bronchiolitis (OB) is based on histopathologic features and/or spirometric staging criteria, using FEV(1) to determine the extent of disease. However, this last parameter reflects an advanced bronchiolar process. The present study investigated whether physiologic parameters reflecting smaller airways dysfunction on one hand, and neutrophils in bronchoalveolar lavage fluid (BALF) on the other hand, could be useful for the earlier detection of bronchiolitis obliterans syndrome (BOS). We analyzed data obtained both from 765 pulmonary function test results and from 467 BALF specimens from 45 patients who survived at least 1 yr after surgery (n = 47, including two retransplantations). Of the transplant procedures, 22 were associated with BOS and 25 were not. The mean delay from transplantation to the diagnosis of BOS was 578 d (range: 122 to 2,619 d). The threshold values of the following parameters were studied: decline in the forced expiratory flow rate at 25% to 75% of FVC (FEF(25-75)) to </= 70% of the predicted value and of baseline values, increase in the slope of the nitrogen washout curve (DeltaN(2)) > 3%, and alveolar neutrophilia >/= 20% of the total BALF cell count. Agreement on the diagnosis of BOS (using the decline in FEV(1)) was equally good for each of the four markers (kappa coefficient > 0.65, p < 10(-)(5)). In the OB group, mean delays after the threshold was reached for each of these parameters were 110 d (p = 0.09), 173 d (p = 0.03), 150 d (p = 0.003), and 131 d (p = 0.1), respectively, before the FEV(1) criteria were fulfilled. At the chosen threshold values, the decline in FEF(25-75), increase in DeltaN(2), and development of a substantial alveolar neutrophilia all occurred significantly before a decline in FEV(1) in posttransplant OB.

Adult↗

Left atrial and ventricular filling in chronic obstructive pulmonary disease. An echocardiographic and Doppler study.

Abnormal left ventricular (LV) diastolic function has frequently been reported in patients with chronic obstructive pulmonary disease (COPD). In the present work, diastolic function was studied by a combined analysis of pulmonary venous and mitral blood flow velocities in 34 patients with COPD clinically stable and without history of heart disease, and 20 control subjects. We confirmed the increased contribution of the atrial contraction to the LV filling in COPD patients in comparison with control subjects; furthermore, a decreased left atrial (LA) filling during the ventricular systole was observed. Changes in LV filling were not the consequence of a systolic dysfunction, because LV systolic function was normal. Doppler indices indicated that LA pressure was below 15 cm H(2)O in all the patients with COPD and control subjects. Several factors can be put forward to explain these changes; the first one is tachycardia. In addition to hypoxemia and medications, echocardiography suggested that a decreased LV preload participated in increased heart rate. Analysis of Doppler transmitral and pulmonary venous flows demonstrated the role of the ventricular interdependence because a correlation existed between LA and LV filling pattern and right ventricle pressure and diameter.

Atrial Function, Left↗

Value of bronchial challenge in scuba diving candidates.

Bronchial challenges were effected with carbachol in 76 subjects who were candidates for a scuba diving group. Bronchial reactivity was assessed through airway resistance and forced expiratory volume in 1 sec (FEV1) measurements. Medical interrogation had revealed symptoms of recent (RA) or ancient (AA) asthma, or allergic rhinitis (AL). Nearly half of the subjects (47%) presented bronchial hyperresponsiveness (BHR), which was much more frequent in the RA group, but whose strength did not depend on clinical presentation. Prevalence of BHR was fairly high (36%) in the AL group. BHR constituted a contraindication to scuba diving because it may promote pulmonary barotrauma.

Adult↗

M-wave changes after high- and low-frequency electrically induced fatigue in different muscles.

The mechanisms of fatigue-induced changes in evoked compound muscle action potential (M-waves) are not well documented. In rats, isolated fast-glycolytic (tibialis anterior, or TA) and slow-oxidative muscles (soleus, or SOL) were stimulated repetitively at a low (10-Hz) or high (80-Hz) rate. Decreased amplitude and prolonged duration of M-waves were only significant after high-frequency fatigue in TA and SOL muscles; that is, in the conditions in which an influx of calcium was measured. On the other hand, maximal force failure and maximal lactic acid increase in the bath medium occurred in TA muscle after high- and low-frequency fatigue trials. Postfatigue increase in potassium concentration occurred in all circumstances. Thus, M-wave alterations depend mainly on the stimulation paradigm and not on the muscle type, and cannot be used as a marker of changes in intracellular potassium or lactate ions. This amplifies understanding of the significance of M-wave changes in human exercise protocols.

Animals↗

Bronchial challenge with carbachol in 3-6-year-old children: body plethysmography assessments.

Several studies of airway responsiveness in young children (3-6 years old) have been reported, but few have attempted measurements of airway resistance by body plethysmography. Therefore, we decided to study nonspecific bronchial responsiveness following cumulative doses of inhaled carbachol in 44 children with clinical asthma (CA group), 44 children with chronic cough (CC group), 38 children with wheezy bronchitis in the first 2 years of life (WB group), and 40 controls. Specific airway resistance (sRaw) was measured in a body plethysmograph, and specific airway conductance (sGaw=1/sRaw) was calculated. Two parameters were used to assess individual bronchial responses: 1) PD100 (the dose of carbachol which induced a 100% increase in sRaw), and 2) bronchial reactivity (BR), i.e., the slope of the log-dose sGaw response to carbachol. Significant differences were observed in PD100 and BR between the control group and the three groups of young patients (P < 0.001). Moreover, PD100 of the CA group was significantly lower than in the CC group (83.1 +/- 7.8 microg vs. 108.0 +/- 10.2 microg, respectively, P < 0.05), but was similar to the WB group PD100 (94.4 +/- 8.5 microg). BR in the CA group was significantly higher than in both the CC and WB groups (0.127 +/- 0.009 cm H2O-L.sec(-1) x log microg(-1) vs. 0.073 +/- 0.006 cm H2O(-1) x sec(-1) x log microg(-1) and 0.082 +/- 0.006 cm H2O(-1) x sec(-1) x log microg(-1), respectively, P < 0.001). Repeatability and coefficients of variation were always acceptable. Continuous SaO2 monitoring in some children of the CA group demonstrated the safety of the method, which is proposed as a technique in future studies.

Asthma↗

Changes in airway resistance induced by nasal or oral intermittent positive pressure ventilation in normal individuals.

Nasal intermittent positive-pressure ventilation (nIPPV) is used for the treatment of respiratory failure in patients with neuromuscular disease. The aim of the present study was to demonstrate that nIPPV may activate nose receptors, the consequence of which being reflex changes in lung resistance. The changes in interrupter resistances (Rint) in response to nIPPV were tested before and after local anaesthesia of the nasal mucosa in normal subjects. They were compared to the Rint changes induced by oral intermittent positive-pressure ventilation (oIPPV) in the same individuals. Rint was measured during 10-min periods of nIPPV or oIPPV at a constant rate (15 L x min(-1)), but at two different stroke volumes (0.8 and 1.2 L). Inspired temperature and relative humidity were held constant. nIPPV with 1.2 L (17 mL x kg(-1)) significantly increased the Rint value (+22%). This effect disappeared after nose anaesthesia or after inhalation of a cholinergic antagonist. oIPPV never changed Rint, even though the associated hypocapnia was present and more accentuated than during nIPPV. Adding CO2 to the inspired gas during nIPPV and oIPPV trials suppressed the Rint changes. The present study suggests the existence of a nasopulmonary bronchoconstrictor reflex elicited through the stimulation of nasal mechanoreceptors, their activity being markedly influenced by the changes in expired CO2 concentration.

Adult↗

Urinary cotinine and exposure to parental smoking in a population of children with asthma.

BACKGROUND: Studies of the effects of tobacco smoke often rely on reported exposure to cigarette smoke, a measure that is subject to bias. We describe here the relationship between parental smoking exposure as assessed by urinary cotinine excretion and lung function in children with asthma. METHODS: We studied 90 children 4-14 years of age, who reported a confirmed diagnosis or symptoms of asthma. In each child, we assessed baseline pulmonary function (spirometry) and bronchial responsiveness to carbachol stimulation. Urinary cotinine was measured by HPLC with ultraviolet detection. RESULTS: Urinary cotinine concentrations in the children were significantly correlated (P <0.001) with the number of cigarettes the parents, especially the mothers, smoked. Bronchial responsiveness to carbachol (but not spirometry test results) was correlated (P <0.03) with urinary cotinine in the children. CONCLUSION: Passive smoke exposure increases the bronchial responsiveness to carbachol in asthmatic children.

Adolescent↗

Correlation between surface electromyogram, oxygen uptake and blood lactate concentration during dynamic leg exercises.

Very few data are found in the literature on the adjustment of the motor drive to contracting muscles to their oxygen uptake (V(O2)). The present study examines in seven untrained and trained individuals, who performed a progressive 8 min and two 5 min constant-load cycling exercises, the changes in the ratio between total EMG energy (root mean square or RMS), recorded in a leg extensor (vastus lateralis), to the corresponding V(O2) value and their correlations with the anaerobic threshold (V(O2)AT) and the peak blood lactate concentration. In all circumstances, the RMS/V(O2) ratio began to increase, then it decreased progressively despite V(O2) continued to rise (progressive exercise) or plateaued (constant-load exercises preseted at a sub- or suprathreshold level). The decrease in RMS/V(O2) ratio persisted and it was often accentuated during the first 2 min of the recovery period. In all exercise protocols, the rate of RMS/V(O2) decrease was positively correlated with the initial peak increase in this ratio. During progressive exercise, the peak increase in RMS/V(O2) ratio as well as its rate of decrease were negatively correlated with V(O2)AT. Thus, training and/or the reduction of anaerobic muscle metabolism attenuate the changes in RMS/V(O2) ratio. During constant-load exercise trials, the rate of decrease in RMS/V(O2) ratio was positively correlated with the plateau V(O2) value and also the peak blood lactate concentration. This suggests that information on the magnitude of the anaerobic muscle metabolism play a key role in the mechanisms which adjust RMS to V(O2).

Adolescent↗

Metabolic and myoelectrical effects of acute hypoxaemia during isometric contraction of forearm muscles in humans: a combined 31P-magnetic resonance spectroscopy-surface electromyogram (MRS-SEMG) study.

1. Failure of muscle force during sustained fatiguing contraction is associated with myoelectrical and metabolic alterations. However, the inter-relationships between these two types of events remain unclear. The purpose of this study was to examine the effects of decreased oxygen availability during sustained contraction on myoelectrical and metabolic changes, thereby addressing the issue of fatigue. 2. 31P-Magnetic resonance spectra and surface electromyograms were simultaneously recorded in six subjects (three women and three men) performing isometric contraction of forearm flexor muscles sustained at 60% maximum value of force under aerobic or acute hypoxaemic conditions (inhalation of a gas mixture containing 12% O2). 3. The 5 min hypoxaemic rest preceding contraction did not affect the phosphocreatine level and pH value. Under both conditions of oxygen availability, the magnitude of metabolic changes remained similar and the duration of contraction was unaffected (similar workload). However, hypoxaemia significantly reduced the rate of changes in integrated surface electromyogram activity measured in the high-frequency band. Correlative analysis of magnetic resonance spectroscopy and surface electromyogram data shows that for a given surface electromyogram change, metabolic variations were always larger under hypoxaemic conditions. 4. These results suggest that hypoxaemia does not alter metabolic changes, i.e. decrease in pH and phosphocreatine during static contraction. The downward shift of the relationships between myoelectrical and metabolic changes under hypoxaemia points to the existence of a better excitation-contraction coupling in acute hypoxaemia compared with normoxia and this is indicative of an adaptative mechanism.

Acute Disease↗