Network


Latest external collaboration on country level. Dive into details by clicking on the dots.

Hotspot


Dive into the research topics where Michael Fayon is active.

Publication


Featured researches published by Michael Fayon.


Proceedings of the National Academy of Sciences of the United States of America | 2003

Dehydroepiandrosterone (DHEA) prevents and reverses chronic hypoxic pulmonary hypertension

Sébastien Bonnet; Eric Dumas-de-La-Roque; Hugues Begueret; Roger Marthan; Michael Fayon; Pierre Dos Santos; Jean-Pierre Savineau; Etienne-Emile Baulieu

Pulmonary artery (PA) hypertension was studied in a chronic hypoxic-pulmonary hypertension model (7–21 days) in the rat. Increase in PA pressure (measured by catheterism), cardiac right ventricle hypertrophy (determined by echocardiography), and PA remodeling (evaluated by histology) were almost entirely prevented after oral dehydroepiandrosterone (DHEA) administration (30 mg/kg every alternate day). Furthermore, in hypertensive rats, oral administration, or intravascular injection (into the jugular vein) of DHEA rapidly decreased PA hypertension. In PA smooth muscle cells, DHEA reduced the level of intracellular calcium (measured by microspectrofluorimetry). The effect of DHEA appears to involve a large conductance Ca2+-activated potassium channel (BKCa)-dependent stimulatory mechanism, at both function and expression levels (isometric contraction and Western blot), via a redox-dependent pathway. Voltage-gated potassium (Kv) channels also may be involved because the antagonist 4-amino-pyridine blocked part of the DHEA effect. The possible pathophysiological and therapeutic significance of the results is discussed.


Journal of Cystic Fibrosis | 2013

Inhaled aztreonam lysine vs. inhaled tobramycin in cystic fibrosis: A comparative efficacy trial

Baroukh M. Assael; Tacjana Pressler; Diana Bilton; Michael Fayon; Rainald Fischer; R. Chiron; Mario LaRosa; Christiane Knoop; Noel G. McElvaney; Sandra A. Lewis; M. Bresnik; A. Bruce Montgomery; Christopher M. Oermann

BACKGROUND Open-label, parallel-group, international trial comparing aztreonam for inhalation solution (AZLI) and tobramycin nebulizer solution (TNS) for cystic fibrosis patients with airway Pseudomonas aeruginosa. METHODS 273 patients (≥ 6 years); randomized to three 28-day courses (AZLI 75 mg [three-times/day] or TNS 300 mg [twice/day]); 28 off-days separated each course. RESULTS 268 patients were treated (AZLI/TNS: 136/132). Mean baseline FEV1 was 52% predicted. Mean relative changes after 1 course (AZLI: 8.35%; TNS: 0.55%; p<0.001) and mean actual changes across 3 courses (AZLI: 2.05%; TNS: -0.66%; p=0.002) indicated AZLI statistical superiority vs. TNS. AZLI-treated patients had fewer respiratory hospitalizations (p=0.044) and respiratory events requiring additional antipseudomonal antibiotics (p=0.004); both treatments were well tolerated. 133 patients received 1 to 3 courses of AZLI treatment in the open-label extension-period (28-day courses separated by 28 days off-treatment); lung function improvements were comparable regardless of whether patients had received TNS or AZLI in the preceding comparative period. CONCLUSIONS AZLI demonstrated statistical superiority in lung function and a reduction in acute pulmonary exacerbations compared to TNS over 3 treatment courses (ClinicalTrials.gov: NCT00757237).


Journal of Pediatric Gastroenterology and Nutrition | 2001

Accidental caustic ingestion in children : is endoscopy always mandatory?

Thierry Lamireau; Laurent Rebouissoux; Delphine Denis; Frantz Lancelin; Pierre Vergnes; Michael Fayon

Background Patients who have experienced severe caustic injury to the gastrointestinal tract are at high risk of esophageal strictures. Early endoscopy is usually recommended systematically in children after caustic ingestion to assess the severity of the initial digestive lesions. The aim of this study was to determine the predictive value of clinical symptoms and ingested-substance types as markers of severe esophagogastric lesions and to define indications for endoscopy. Methods Ingested-product types, clinical symptoms, endoscopic data and outcome were prospectively recorded in 85 children admitted after accidental caustic ingestion. Results Forty-eight children (57%) had no symptoms; the others presented with vomiting, hematemesis, drooling, respiratory distress, and/or oropharyngeal lesions. Endoscopy showed no or minimal lesions in 63 cases (74%). None of the children developed digestive sequelae. Severe esophagogastric lesions were present in 22 cases (26%), mostly caused by lye ingestion (14 of 22) but also by strong acids (4 of 22); 9 of the 22 children (41%) developed esophageal stenosis. Vomiting, drooling, and oropharyngeal lesions did not predict severe endoscopic lesions. Hematemesis, respiratory distress, or presence of at least three of the symptoms was associated with severe lesions (positive predictive value = 1). The absence of symptoms was always associated with no or minimal lesions (negative predictive value = 1). Conclusions In conclusion, endoscopy is not recommended for children living in developed countries who are asymptomatic after accidental caustic ingestion.


Pediatric Research | 2001

Prolonged Moderate Hyperoxia Induces Hyperresponsiveness and Airway Inflammation in Newborn Rats

Delphine Denis; Michael Fayon; Patrick Berger; Mathieu Molimard; Manuel Tunon de Lara; Etienne Roux; Roger Marthan

Bronchopulmonary dysplasia is the most common cause of chronic pulmonary disease in premature infants. Airway inflammation appears to play a major pathogenetic role together with barotrauma and oxygen toxicity. The aim of the present study was to determine the effect of a 15-d exposure to moderate hyperoxia (Fio2, 50%) on airway reactivity and inflammatory response in neonatal and adult rats. We studied in isolated tracheal rings the 1) isometric contraction to cumulative concentrations of carbachol (10−8 to 10−3 M);2) epithelial, submucosal, smooth muscle, and connective tissue surface area; and 3) distribution of inflammatory cells (mastocytes, granulocytes, macrophages) by using MAb. Reactivity to carbachol was significantly increased in the hyperoxic pups, in which a 13% increase in tracheal smooth muscle surface area was observed. Type-I mast cells and macrophages (submucosa and connective tissue) and granulocytes (connective tissue) were increased in the neonatal hyperoxic group. Hyperoxia did not influence functional, morphometric, or cellular data in adult rats. In conclusion, exposure of newborn rats to moderate hyperoxia induces airway hyperresponsiveness and histologic changes similar to those reported in bronchopulmonary dysplasia. Hyperresponsiveness may be ascribed to an increase in smooth muscle related to the release of yet undetermined mediators by inflammatory cells infiltrating the airways. Lung immaturity definitely plays a role because similar alterations are not observed in adult rats.


Drug Safety | 2008

Inhaled Corticosteroids and Adrenal Insufficiency

Mathieu Molimard; Pierre-Olivier Girodet; Clothilde Pollet; Annie Fourrier-Réglat; Amélie Daveluy; Françoise Haramburu; Michael Fayon; Antoine Tabarin

AbstractObjective: Adrenal insufficiency (AI) is a potentially life-threatening condition. It is known that high doses of inhaled corticosteroids (ICS) can induce systemic adverse effects. Currently, there are no data on the prevalence of AI associated with the use of ICS. This study aimed to investigate the prevalence and clinical presentation of AI (associated or not associated with exogenous Cushing’s syndrome) in patients who were prescribed ICS by French physicians during the period 2000–5. Methods: All metropolitan French paediatricians, endocrinologists, pulmonologists and intensive care physicians (n = 11 783) were mailed questionnaires requesting information regarding cases of AI associated or not associated with exogenous Cushing’s syndrome between 2000 and 2005. Data collected included patient demographics, oral corticosteroid or ICS used during the year preceding the diagnosis of AI, underlying condition(s), concomitant treatment(s), presenting clinical signs and symptoms, results of laboratory investigations and outcome. The French pharmacovigilance database was screened for spontaneous reports to determine the frequency of AI associated with the use of ICS, using the capturerecapture method. Results: Forty-six cases of AI were identified. Twenty-three cases presented with clinical symptoms of AI alone and 23 with exogenous Cushing’s syndrome. ICS prescribed were fluticasone propionate (n = 24), budesonide (n = 12) and beclometasone dipropionate (n = 5). In 82% (n = 32) of cases for which data were available, ICS were prescribed at high doses. A potential drug interaction was found in 12 cases. Thirteen cases of AI were identified in the French pharmacovigilance database, one of which was common with the questionnaire survey. The capture-recapture method provided an estimation of 598 (95% CI 551, 648) cases of AI associated with the use of ICS for the 2000–5 period in France. Conclusion: The results of this study confirm the occurrence of adrenal insufficiency in patients treated with ICS. Although the prevalence of ICS-induced AI reported in this study is low, the likelihood of under-diagnosis underlines the need to consider this risk in patients when prescribing these drugs.


Radiology | 2015

Quiet Submillimeter MR Imaging of the Lung Is Feasible with a PETRA Sequence at 1.5 T

Gaël Dournes; David Grodzki; Julie Macey; Pierre-Olivier Girodet; Michael Fayon; Jean-François Chateil; Michel Montaudon; Patrick Berger; François Laurent

Quiet submillimeter MR imaging of the lung is feasible with the pointwise encoding time reduction with radial acquisition, or PETRA, sequence at 1.5 T.


Gastroenterology | 1992

Fatal neonatal liver failure and mitochondrial cytopathy: An observation with antenatal ascites

Michael Fayon; Thierry Lamireau; Paulette Bioulac-Sage; Thierry Letellier; Brigitte Moretto; Françoise Parrot-Roulaud; Michelle Coquet; Monique Malgat; Jean Sarlangue; Charles Balabaud; J.L. Demarquez; Jean Pierre Mazat

Mitochondrial cytopathies are multisystemic diseases of extremely variable expression caused by a deficiency in oxidative phosphorylation. Only five cases of neonatal liver failure in the context of mitochondrial cytopathy have been reported, with incomplete morphological data of the liver in three. In the case presented here, ascites had been diagnosed prenatally and liver failure was particularly severe (factor V less than 15% with fatal coma the fourth day). Histologically there were incomplete cirrhosis, microvesicular steatosis, major canalicular cholestasis with proliferative neocholangioles, and bile duct thrombi. There were also some iron pigments in the periportal area and partial glycogen depletion. By electron microscopy, mitochondria in numerous hepatocytes appeared abnormal with occasional cristae in a fluffy matrix, some containing dense inclusions. Study of respiratory chain activity showed a defect in cytochrome c oxidase (complex IV), revealed by oxygraphic measurement on fresh muscle biopsy and confirmed by spectrophotometric enzymatic assays performed on muscle and liver homogenates. The association of neonatal liver failure with hyperlactacidemia warrants investigation into a deficiency in oxidative phosphorylation.


Annales D Endocrinologie | 2012

Dehydroepiandrosterone (DHEA) improves pulmonary hypertension in chronic obstructive pulmonary disease (COPD): a pilot study.

Eric Dumas De La Roque; Jean-Pierre Savineau; Anne-Cécile Metivier; Marc-Alain Billes; Jean-Philippe Kraemer; Stéphane Doutreleau; Jacques Jougon; Roger Marthan; Nicholas Moore; Michael Fayon; Etienne-Emile Baulieu; Claire Dromer

OBJECTIVES It was previously shown that dehydroepiandrosterone (DHEA) reverses chronic hypoxia-induced pulmonary hypertension (PH) in rats, but whether DHEA can improve the clinical and hemodynamic status of patients with PH associated to chronic obstructive pulmonary disease (PH-COPD) has not been studied whereas it is a very severe poorly treated disease. PATIENTS AND METHODS Eight patients with PH-COPD were treated with DHEA (200mg daily orally) for 3 months. The primary end-point was the change in the 6-minute walk test (6-MWT) distance. Secondary end-points included pulmonary hemodynamics, lung function tests and tolerance of treatment. RESULTS The 6-MWT increased in all cases, from 333m (median [IQR]) (257; 378) to 390m (362; 440) (P<0.05). Mean pulmonary artery pressure decreased from 26mmHg (25; 27) to 21.5mmHg (20; 25) (P<0.05) and pulmonary vascular resistance from 4.2UI (3.5; 4.4) to 2.6UI (2.5; 3.8) (P<0.05). The carbon monoxide diffusing capacity of the lung (DLCO % predicted) increased significantly from 27.4% (20.1; 29.3) to 36.4% (14.6; 39.6) (P<0.05). DHEA treatment did not change respiratory parameters of gas exchange and the 200mg per day of DHEA used was perfectly tolerated with no side effect reported. CONCLUSION DHEA treatment significantly improves 6-MWT distance, pulmonary hemodynamics and DLCO of patients with PH-COPD, without worsening gas exchange, as do other pharmacological treatments of PH (trial registration NCT00581087).


European Respiratory Journal | 2015

Real-life long-term omalizumab therapy in children with severe allergic asthma

Antoine Deschildre; Christophe Marguet; Carole Langlois; Isabelle Pin; Jean-Luc Rittié; Jocelyne Derelle; Rola Abou Taam; Michael Fayon; Jacques Brouard; Jean-Christophe Dubus; Daniel Siret; Laurence Weiss; G. Pouessel; Laurent Béghin; Jocelyne Just

We previously reported the French real-life experience of 1 year of add-on treatment with omalizumab in 101 severe allergic asthmatic children (6–18 years), 92 of whom were still receiving the treatment at the end of the first year [1]. The study provided complementary data to the previous randomised trials [2–6]. We showed a marked drop of 72% in the mean rate of severe exacerbations (from 4.4 per patient during the preceding year to 1.25 during the year of treatment) and of 88.5% for hospitalisations (44% of the patients during the preceding year to 6.7% during the year of treatment); a large improvement in asthma control (from 0% at initiation to 67% of well-controlled patients after 1 year); a decrease of 30% of the mean inhaled corticosteroid (ICS) dose (from 703 at initiation to 488 µg fluticasone equivalent per day after 1 year); and a forced expiratory volume in 1 s (FEV1) increase, from a mean of 88% to 92.1% of the predicted value. Treatment was discontinued in six patients due to serious adverse events attributed to omalizumab by the practitioner. Here we report the outcome of this cohort after 2 years of omalizumab treatment. Beneficial effects at 2 years of omalizumab on severe exacerbations and control in severe allergic asthmatic children http://ow.ly/LGgnw


European Radiology | 2016

Lung morphology assessment of cystic fibrosis using MRI with ultra-short echo time at submillimeter spatial resolution

Gaël Dournes; Fanny Menut; Julie Macey; Michael Fayon; Jean-François Chateil; Marjorie Salel; O. Corneloup; Michel Montaudon; P. Berger; François Laurent

AbstractObjectivesWe hypothesized that non-contrast-enhanced PETRA (pointwise encoding time reduction with radial acquisition) MR (magnetic resonance) sequencing could be an alternative to unenhanced computed tomography (CT) in assessing cystic fibrosis (CF) lung structural alterations, as well as compared agreements and concordances with those of conventional T1-weighted and T2-weighted sequences.Material and methodsThirty consecutive CF patients completed both CT and MRI the same day. No contrast injection was used. Agreement in identifying structural alterations was evaluated at the segmental level using a kappa test. Intraclass correlation coefficients (ICC) and Bland-Altman analysis were used to assess concordances and reproducibility in Helbich-Bhalla disease severity scoring.ResultsAgreement between PETRA and CT was higher than that of T1- or T2-weighted sequences, notably in assessing the segmental presence of bronchiectasis (Kappa = 0.83; 0.51; 0.49, respectively). The concordance in Helbich-Bhalla scores was very good using PETRA (ICC = 0.97), independently from its magnitude (mean difference (MD) = -0.3 [-2.8; 2.2]), whereas scoring was underestimated using both conventional T1 and T2 sequences (MD = -3.6 [-7.4; 0.1]) and MD = -4.6 [-8.2; -1.0], respectively). Intra- and interobserver reproducibility were very good for all imaging modalities (ICC = 0.86-0.98).ConclusionPETRA showed higher agreement in describing CF lung morphological changes than that of conventional sequences, whereas the Helbich-Bhalla scoring matched closely with that of CT.Key Points• Spatial resolution of lung MRI is limited using non-ultra-short TE MRI technique • Ultra-short echo time (UTE) technique enables submillimeter 3D-MRI of airways • 3D-UTE MRI shows very good concordance with CT in assessing cystic fibrosis • Radiation-free 3D-UTE MRI enables the Helbich-Bhalla scoring without a need for contrast injection

Collaboration


Dive into the Michael Fayon's collaboration.

Top Co-Authors

Avatar

S. Bui

University of Bordeaux

View shared research outputs
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar

Jacques de Blic

Necker-Enfants Malades Hospital

View shared research outputs
Top Co-Authors

Avatar

Mathieu Molimard

École Normale Supérieure

View shared research outputs
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Researchain Logo
Decentralizing Knowledge