Biomedical subjects

Annick Clément

Publications and source records attributed to Annick Clément.

17 recordsLinked to original sources

PubMed2006

Respiratory muscle testing: a valuable tool for children with neuromuscular disorders.

RATIONALE: Data on respiratory muscle performance in children with neuromuscular disorders are limited. OBJECTIVES: The aim of this study was to assess respiratory muscle strength by volitional and nonvolitional tests and to compare these tests with forced vital capacity. METHODS: Inspiratory muscle strength was assessed by measuring transdiaphragmatic and esophageal pressures generated during volitional and nonvolitional maneuvers, whereas expiratory muscle strength was assessed by measuring the gastric pressure generated during a cough maneuver. Lung volumes were assessed by measuring forced vital capacity. MEASUREMENTS AND MAIN RESULTS: Forty-one patients with Duchenne muscular dystrophy (n = 20), spinal amyotrophy (n = 8), and congenital myopathy (n = 13) were included, aged 2 to 18 yr. All the patients were able to perform the sniff and the cough maneuver. Sniff transdiaphragmatic pressure decreased with age in Duchenne patients, whereas it increased with age in patients with spinal amyotrophy and congenital myopathy. Magnetic stimulation of the phrenic nerves was obtained in all patients. Twenty-five (61%) patients were able to perform forced vital capacity. In the three groups of patients, a positive correlation was observed between volitional, assessed by the sniff maneuver, and nonvolitional respiratory muscle tests, assessed by the magnetic stimulation of the phrenic nerves. Also, forced vital capacity correlated with sniff transdiaphragmatic pressure and cough gastric pressure. CONCLUSIONS: Volitional respiratory muscle tests correlated with nonvolitional tests and with forced vital capacity. Simple volitional respiratory muscle tests constitute a valuable tool for the assessment of respiratory muscle strength in young patients with neuromuscular disorders.

Adolescent↗

PubMed2005

Mechanical limitation during CO2 rebreathing in young patients with cystic fibrosis.

The aim of the study was to determine whether a decrease in the ventilatory response to carbon dioxide (CO2) in children with cystic fibrosis (CF) is related to a mechanical limitation of the respiratory muscle capacity. The ventilatory response during CO2 rebreathing was performed in 15 patients (mean forced expiratory volume in 1 s (FEV1): 37 +/- 21% predicted, mean arterial CO2: 41+/- 5 mmHg). The slope of the minute ventilation normalised for weight per mmHg CO2 increment correlated negatively with respiratory muscle output, assessed by the oesophageal (p = 0.002), the diaphragmatic pressure time product (p = 0.01), and the tension time index (p = 0.005). In addition, this slope was correlated with dynamic lung compliance (p < 0.0001) and FEV1 (p = 0.03) but not with airway resistance and maximal transdiaphragmatic pressure. Therefore, an excessive load imposed on the respiratory muscles explains the blunting of the ventilatory response to CO2 in young patients with CF.

Adolescent↗

PubMed2005

Adherence of airway neutrophils and inflammatory response are increased in CF airway epithelial cell-neutrophil interactions.

Persistent presence of PMN in airways is the hallmark of CF. Our aim was to assess PMN adherence, percentage of apoptotic airway PMN (aPMN), and IL-6 and IL-8 production when aPMN are in contact with airway epithelial cells. Before coculture, freshly isolated CF aPMN have greater spontaneous and TNF-alpha-induced apoptosis compared with blood PMN from the same CF patients and from aPMN of non-CF patients. We then examined cocultures of PMN isolated from CF and non-CF airways with bronchial epithelial cells bearing mutated cftr compared with cftr-corrected bronchial epithelial cells. After 18-h coculture, the number of CF aPMN adhered on cftr-deficient bronchial epithelial cells was 2.3-fold higher compared with the coculture of non-CF aPMN adhered on cftr-corrected bronchial epithelial cells. The percentage of CF apoptotic aPMN (9.5 +/- 0.2%) adhered on cftr-deficient bronchial epithelial cells was similar to the percentage of non-CF apoptotic aPMN adhered on cftr-corrected bronchial epithelial cells (10.3 +/- 0.7%). IL-6 and IL-8 levels were enhanced 6.5- and 2.9-fold, respectively, in coculture of CF aPMN adhered on cftr-deficient bronchial epithelial cells compared with coculture of non-CF aPMN adhered on cftr-corrected bronchial epithelial cells. Moreover, blocking surface adhesion molecules ICAM-1, VCAM-1, and E-selectin on cftr-deficient bronchial epithelial cells with specific MAbs inhibited the adherence of CF aPMN by 64, 51, and 50%, respectively. Our data suggest that in CF patients a high number of nonapoptotic PMN adhered on airway epithelium associated with elevated IL-6 and IL-8 levels may contribute to sustained and exaggerated inflammatory response in CF airways.

Adolescent↗

PubMed2005

Carcinoid and mucoepidermoid bronchial tumours in children.

UNLABELLED: The aim of the study was to determine the characteristic features and outcome of carcinoid or mucoepidermoid tumours in children. A retrospective analysis of all patients treated for a carcinoid or mucoepidermoid tumour in France between 1984 and 2001 was performed. There were 11 cases of carcinoid tumour and 6 cases of mucoepidermoid tumour. The mean age of the patients was 10.5+/-3.0 years, with a range of 5 to 15 years. Twelve and 6 patients presented with evidence of bronchial obstruction and haemoptysis, respectively. Fibre optic bronchoscopy confirmed the presence of a bronchial tumour in all cases and endobronchial biopsies were diagnostic in 11 of 12 cases. A chest CT scan revealed the presence of a hypervascular tumour in 8 of 12 patients. The distribution of the location of the tumours was equal between the right and the left lung, and, in 9 cases, the airways were totally occluded by the tumour. Complete surgical resection (lobectomy in 15 patients and pneumonectomy in 2 patients) was performed in all cases without pre-operative chemotherapy or radiotherapy. The mean duration of follow-up was 4.0+/-3.0 years. In 2 patients, auscultation assymetry and an episode of haemoptysis revealed the recurrence of a mucoepidermoid tumour, successfully cured by removal of the tumour and chemotherapy and radiotherapy in one child. No death was observed. CONCLUSION: Pulmonary carcinoid and mucoepidermoid tumours are rare in children. Bronchoscopic removal should not be performed. With aggressive surgical therapy, the prognosis is excellent. Fibre optic bronchoscopy confirms the presence of an endobronchial mass. A biopsy is needed for diagnosis and complete surgical removal is the treatment of choice. Long-term results are excellent but a clinical follow-up is recommended.

Adolescent↗

PubMed2005

Calcium-dependent regulation of NF-(kappa)B activation in cystic fibrosis airway epithelial cells.

Dysregulation of nuclear factor kappa B (NF-(kappa)B) and increased Ca(2+) signals have been reported in airway epithelial cells of patients with cystic fibrosis (CF). The hypothesis that Ca(2+) signaling may regulate NF-(kappa)B activation was tested in a CF bronchial epithelial cell line (IB3-1, CFTR genotype DeltaF508/W1282X) and compared to the CFTR-corrected epithelial cell line S9 using fluorescence microscopy to visualized in situ NF-(kappa)B activation at the single cell level. Upon stimulation with IL-1beta,we observed a slow but prolonged [Ca(2+)](i) increase (up to 10 min) in IB3-1 cells compared to S9 cells. The IL-1beta-induced [Ca(2+)](i) response was accompanied by an activation of NF-(kappa)B in IB3-1 but not in S9 cells. Pretreatment of IB3-1 cells with the ER Ca(2+) pump inhibitor thapsigargin inhibited the IL-1beta-induced [Ca(2+)](i) response. Treatment with either the calcium chelator BAPTA or an inhibitor of I(kappa)Balpha phosphorylation (digitoxin) led to a drastic [Ca(2+)](i) decrease accompanied by an inhibition of NF-(kappa)B activation of IL-1beta-stimulated IB3-1 cells in comparison to untreated cells. In IB3-1 cells cultured at low temperature (26 degrees C) for 16 h, the IL-1beta-induced [Ca(2+)](i) response was inhibited and no significant NF-(kappa)B activation was observed. To our knowledge, this is the first report of visualization of the Ca(2+)-mediated activation of NF-(kappa)B in individual living airway epithelial cells. Our results support the concept that [Ca(2+)](i) is a key regulator of NF-(kappa)B activation in CF airway epithelial cells.

Calcium↗

PubMed2005

Facial side effects during noninvasive positive pressure ventilation in children.

OBJECTIVE: The study quantified the side effects of nasal masks use for noninvasive positive pressure ventilation (NPPV) in children. DESIGN AND SETTING: Cross-sectional retrospective study in a tertiary pediatric university hospital. PATIENTS: Patients with obstructive sleep apnea (n=16), neuromuscular disorders (n=14), and cystic fibrosis (n=10). INTERVENTIONS: Clinical evaluation of facial tolerance. MEASUREMENTS AND RESULTS: A skin injury was observed in 19 patients (48%), with a transient erythema in 7 (18%), prolonged erythema in 9 (23%), and skin necrosis in 3 (8%). Skin injury was associated with age over 10 years (OR=16) and use of a commercial mask (OR=15) and was less frequent in patients with obstructive sleep apnea. The change of a commercial mask for a custom-made mask was associated with reduction in the skin injury score. Global facial flattening was present in 68% of the patients. No correlation was observed with age, daily or cumulative use of NPPV, or the type of mask. A maxillary retrusion was present in 37% of patients. No correlation was observed with age or the type of mask or the underlying disease, but an association was found with a longer daily use of NPPV (OR=6.3). CONCLUSIONS: The prevalence of facial side effects is clinically significant in children using NPPV. Systematic maxillofacial follow-up enables these effects to be identified. Remedial measures could include the change of the interface or reducing the daily use of NPPV.

Adolescent↗

PubMed2005

Noninvasive positive pressure ventilation in infants with upper airway obstruction: comparison of continuous and bilevel positive pressure.

OBJECTIVE: This study evaluated the efficacy of noninvasive continuous positive pressure (CPAP) ventilation in infants with severe upper airway obstruction and compared CPAP to bilevel positive airway pressure (BIPAP) ventilation. DESIGN AND SETTING: Prospective, randomized, controlled study in the pulmonary pediatric department of a university hospital. PATIENTS: Ten infants (median age 9.5 months, range 3-18) with laryngomalacia (n=5), tracheomalacia (n=3), tracheal hypoplasia (n=1), and Pierre Robin syndrome (n=1). INTERVENTIONS: Breathing pattern and respiratory effort were measured by esophageal and transdiaphragmatic pressure monitoring during spontaneous breathing, with or without CPAP and BIPAP ventilation. MEASUREMENTS AND RESULTS: Median respiratory rate decreased from 45 breaths/min (range 24-84) during spontaneous breathing to 29 (range 18-60) during CPAP ventilation. All indices of respiratory effort decreased significantly during CPAP ventilation compared to unassisted spontaneous breathing (median, range): esophageal pressure swing from 28 to 10 cmH(2)O (13-76 to 7-28), esophageal pressure time product from 695 to 143 cmH(2)O/s per minute (264-1417 to 98-469), diaphragmatic pressure time product from 845 to 195 cmH(2)O/s per minute (264-1417 to 159-1183) During BIPAP ventilation a similar decrease in respiratory effort was observed but with patient-ventilator asynchrony in all patients. CONCLUSIONS: This short-term study shows that noninvasive CPAP and BIPAP ventilation are associated with a significant and comparable decrease in respiratory effort in infants with upper airway obstruction. However, BIPAP ventilation was associated with patient-ventilator asynchrony.

Airway Obstruction↗

PubMed2005

Paediatric sarcoidosis.

Sarcoidosis is a multisystem granulomatous disease of unknown aetiology, most commonly affecting young adults. Divergent prevalence rates and clinical appearances in different races indicate the existence of predisposing genes, with probably a major effect of the major histocompatibility complex. The diagnosis is relatively rare in children. Lesions can occur in almost any tissue or organ but the lungs, lymph nodes, eyes, skin and liver are the most commonly involved. Clinical symptoms are non-specific and often minor. The diagnosis can only be supported by typical histopathological findings with non-caseating epithelioid-cell granulomas. The prognosis seems to be more severe in younger children and in cases of multi-organ involvement. Corticosteroids are the therapeutic agents most commonly used and are indicated in cases of significant lung or eye lesions, cardiac, neurological, or multiorgan involvement. Close monitoring is mandatory during and after treatment because relapses are common.

Arthritis↗

PubMed2004

The effect of back-up rate during non-invasive ventilation in young patients with cystic fibrosis.

OBJECTIVE: The aim of the study was to evaluate the effect of the back-up rate on respiratory effort during non-invasive mechanical ventilation. DESIGN: An in vitro study evaluated the inspiratory trigger in seven domiciliary ventilators. Then, a prospective, randomized, crossover trial compared the effect on respiratory effort of three different back-up rates during pressure support (PS) and assist-control/volume-targeted (AC/VT) ventilation. SETTING: A research unit and a tertiary referral pediatric center. PATIENTS: Ten patients with cystic fibrosis (CF). INTERVENTIONS: During the in vivo study, the back-up rate was progressively increased to the maximum that patients could tolerate (Fmax) and respiratory effort, as judged by pressure/time product of the diaphragm (PTPdi/min), was compared between the two ventilatory modes. RESULTS: Differences were observed between trigger pressure, trigger time delay, trigger pressure/time product and the slope between flow and pressure in the seven ventilators. PS and AC/VT ventilation were associated with a decrease in respiratory effort (PTPdi/min was 518+/-172, 271+/-119 and 291+/-138 cmH(2)O. s(-1). min(-1), for spontaneous breathing, PS and AC/VT ventilation, respectively, p=0.05). During the two modes, increasing the back-up rate to Fmax resulted in a greater reduction in PTPdi/min (p=0.001), which was more pronounced during AC/VT ventilation, due to the automatic adjustment of the inspiratory/expiratory time ratio. CONCLUSIONS: Increasing the back-up rate during PS and AC/VT ventilation decreases respiratory effort in young patients with CF, but this effect was more marked with AC/VT ventilation.

Adolescent↗

PubMed2004

Clinical presentation of interstitial lung disease in children.

Interstitial lung disease (ILD) in children represents a heterogeneous group of rare lung disorders characterised by an inflammatory process of the alveolar wall and the pulmonary interstitium, which share common clinical, radiological and histological findings. Clinical presentation of paediatric ILD is non-specific and variable. Respiratory signs and symptoms include tachypnoea, rapid shallow breathing, retractions, cyanosis and crackles. Failure to thrive and respiratory distress are common in infants. Dyspnoea on exertion is a symptom encountered in older children. Non-respiratory symptoms can be present when ILD is part of a systemic disorder. Although non-specific and variable, the clinical presentation at the time of diagnosis has some prognostic value.

Child↗

PubMed2004

Nutritional status is an important predictor of diaphragm strength in young patients with cystic fibrosis.

BACKGROUND: The effect of nutritional status and lung disease progression on diaphragm strength in young patients with cystic fibrosis remains unclear. OBJECTIVE: The aim of this study was to investigate the effect of nutritional status and airway obstruction on diaphragm strength. DESIGN: Twitch transdiaphragmatic pressure (Tw Pdi) obtained by bilateral anterior magnetic phrenic nerve stimulation, body mass index (BMI) z score, fat mass, fat-free mass (FFM), arm muscle circumference (AMC), forced expiratory volume in 1 s (FEV(1)), and functional residual capacity (FRC) were measured in 20 patients aged 15.1 +/- 2.8 y (x +/- SD). Values were expressed as a percentage of predicted values. RESULTS: Mean (+/-SD) Tw Pdi was 24.3 +/- 5.5 cm H(2)O. Univariate regression analysis showed positive correlations between Tw Pdi and nutrition scores (BMI z score: r = 0.63, P = 0.003; FFM: r = 0.47, P = 0.04; AMC: r = 0.45, P = 0.04), airway obstruction (FEV(1): r = 0.68, P = 0.001), and arterial oxygen partial pressure (r = 0.68, P = 0.001). Negative correlations were observed between Tw Pdi and dynamic hyperinflation (FRC: r = -0.65, P = 0.005) and arterial carbon dioxide pressure (r = -0.50, P = 0.03). Furthermore, stepwise regression analysis showed that Tw Pdi correlated with BMI z score (r = 0.75, P = 0.0002) and FEV(1) (r = 0.69, P = 0.001). CONCLUSIONS: Diaphragm strength is relatively well preserved in young patients with cystic fibrosis. However, the strength of the diaphragm decreases with the progression of malnutrition and airway obstruction.

Adolescent↗

PubMed2004

Burkholderia cepacia is associated with pulmonary hypertension and increased mortality among cystic fibrosis patients.

The aim of the study was to evaluate the impact of Burkholderia cepacia on cardiovascular status and mortality in cystic fibrosis. Seven patients infected with B. cepacia were matched with 31 patients not infected with this organism for gender, age, height, weight, genotype, and percent predicted forced expiratory volume in one second, partial arterial oxygen pressure, and pancreatic sufficiency status. The pulmonary artery systolic pressure, as assessed by transthoracic echocardiography, was significantly higher in patients infected with B. cepacia (61.3 +/- 17.2 mm Hg) than in controls (37.3 +/- 13.9 mm Hg; P = 0.02), and the mean acceleration time was significantly lower (77 +/- 33 ms versus 108 +/- 25 ms; P = 0.02). The 6-month mortality was significantly higher in patients infected with B. cepacia (57% versus 16%; P = 0.02). Six of the seven patients infected with B. cepacia harbored the same ribotype (genomovar II, B. multivorans). Pulmonary hypertension was significantly more frequent in patients infected by B. cepacia and could contribute to the increased mortality rate.

Adolescent↗

PubMed2004

The efficacy of premixed nitrous oxide and oxygen for fiberoptic bronchoscopy in pediatric patients: a randomized, double-blind, controlled study.

STUDY OBJECTIVE: s: The aim of the study was to evaluate the efficacy and safety of premixed 50% nitrous oxide and oxygen on the quality of sedation and pain control during fiberoptic bronchoscopy (FB) in children. DESIGN: A prospective, randomized, double-blind study. SETTING: Pediatric pulmonary department in a pediatric tertiary university hospital. PATIENTS: One hundred five children aged 1 month to 18 years. INTERVENTIONS: Patients inhaled after sedation and local anesthesia either premixed 50% nitrous oxide and oxygen (nitrous oxide group) or premixed 50% nitrogen and oxygen (control group) during FB. MEASUREMENT AND RESULTS: The rate of failure was significantly greater in the control group (62%) than in the nitrous oxide group (21%, p = 0.00003). The efficacy of premixed 50% nitrous oxide and oxygen was also demonstrated with higher satisfaction scores (p = 0.000001), lower Children's Hospital of Eastern Ontario Pain Scores (p = 0.002), better visual analog scale ratings (p = 0.03), and improved behavior scores. Side effects were minor and similar in both groups. CONCLUSIONS: This study demonstrates the improved efficacy of sedation, pain control, and safety of premixed 50% nitrous oxide and oxygen for FB in children.

Adolescent↗

PubMed2003

Reduction of chemokine IL-8 and RANTES expression in human bronchial epithelial cells by a sea-water derived saline through inhibited nuclear factor-kappaB activation.

The NaCl content of airway surface fluid is believed to be of central importance in lung pathology. To test whether the Na+ concentration could influence the inflammatory response in human bronchial epithelial cells (BECs), we investigated the interleukin (IL)-8 and RANTES expression in BECs exposed to an isotonic sea-water derived low Na+ (ISW) saline compared to isotonic 0.9% NaCl saline. Exposure of BECs to ISW saline caused a significant decrease in IL-8 and RANTES gene expression and protein production as compared to that observed with 0.9% NaCl saline. Furthermore, we observed a concomitant reduction of phosphorylated IkappaBalpha associated with a marked inhibition of NF-kappaB-DNA binding activity in BECs exposed to ISW saline as compared to 0.9% NaCl saline. These findings support a new role for Na+ in the pathogenesis of airway inflammatory disorders. Therapies targeted at lowering Na+ level in airway epithelium may be beneficial in treating inflammatory lung diseases.

Cell Survival↗

PubMed2003

[Protein repair therapy in cystic fibrosis].

In the past few years since the cloning of the gene defective in cystic fibrosis, much has been learned on the function of the protein cystic fibrosis transmembrane conductance regulator (CFTR) and on the mechanisms regulating its expression. Based on the current understanding of the processes involved in lung disease progression, a number of approaches have been developed using not only gene therapy, but also pharmacological agents. Several of these agents have been reported to restore function to CFTR with specific mutations.

Cystic Fibrosis↗

PubMed2002

Changes in pulmonary mechanics with increasing disease severity in children and young adults with cystic fibrosis.

As forced expiratory volume in 1 second (FEV(1)) is a major predictor of outcome in patients with cystic fibrosis (CF), we investigated the effect of FEV(1) on pulmonary mechanics in children and young adults with CF. We measured respiratory rate; tidal volume; minute ventilation; arterial blood gases; sniff esophageal pressure; dynamic lung compliance; total pulmonary resistance; intrinsic positive end expiratory pressure; and total, elastic, and resistive work of breathing in 32 patients (FEV(1) range: 12-49% predicted). We observed correlations between FEV(1) and Pa(O(2)) (r = 0.76, p < 0.0001) and Pa(CO(2)) (r = -0.70, p < 0.0001), FEV(1) and respiratory rate/tidal volume (r = -0.41, p = 0.02), FEV(1) and dynamic lung compliance (r = 0.64, p < 0.0001), and FEV(1) and total work of breathing (r = -0.52, p = 0.002) and elastic work of breathing (r = -0.60. p = 0.0003). No correlations were observed between FEV(1) and sniff esophageal pressure (p = 0.5), minute ventilation (p = 0.9), total pulmonary resistance (p = 0.3), intrinsic positive end expiratory pressure (p = 0.3), or resistive work of breathing (p = 0.1). As FEV(1) declines in children and young adults with CF, there is an increase in the elastic load and work of breathing, resulting in a rapid shallow breathing pattern, that is associated with further impairment of gas exchange.

Adolescent↗

PubMed2002

Depression of diaphragm contractility by nitrous oxide in humans.

UNLABELLED: Nitrous oxide is widely used in anesthesia and critical care medicine. The effect of nitrous oxide on diaphragm contractility in humans is unknown. We evaluated the effect of a 50% nitrous oxide-50% oxygen mixture on diaphragm contractility in healthy adult volunteers. The sniff transdiaphragmatic pressure (Sn Pdi) and the twitch transdiaphragmatic pressure (Tw Pdi) elicited by bilateral supramaximal phrenic nerve stimulation were measured before during and after inhalation of a mixture of 50% nitrous oxide and 50% oxygen. Sn Pdi decreased by 15.4% during nitrous oxide inhalation, with a value of 136 +/- 21 cm H(2)O before nitrous oxide and a value of 115 +/- 27 cm H(2)O during nitrous oxide inhalation (P = 0.03). Similarly, Tw Pdi decreased from 21.2 +/- 1.8 cm H(2)O before nitrous oxide inhalation to 16.9 +/- 4.1 cm H(2)O during nitrous oxide inhalation (P = 0.03). The effect of nitrous oxide was totally abolished 20 min after its discontinuation. Nitrous oxide has a short-acting suppressant effect on the pressure generating capacity of the diaphragm in healthy humans. IMPLICATIONS: We investigated whether nitrous oxide (a common component of gas anesthesia) reduces diaphragm strength in humans. Diaphragm strength is reduced by nitrous oxide but the effect wears off within 20 min of administration. Caution is advised when using nitrous oxide without anesthesiologist supervision in patients at risk of ventilatory failure

Administration, Inhalation↗