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Alain Didier

Publications and source records attributed to Alain Didier.

9 recordsLinked to original sources
PubMed2006

How reliable is the structural prediction of IgE-binding epitopes of allergens? The case study of plant lipid transfer proteins.

The linear IgE-binding epitopes of non-specific lipid transfer proteins (nsLTP) from plants were predicted using a combination of predictive tools including (1) the hydropathic profiles based on different scales of hydrophilicity, flexibility and exposure to the solvent, (2) the hydrophobic cluster analysis plots, (3) the occurrence of charged residues in the predicted amino acid sequence stretches and, (4) the exposition of the predicted linear IgE-binding epitopes checked on the three-dimensional models built for the nsLTP. A reliable prediction was obtained for nsLTP as compared with the previously characterized IgE-binding epitopes of various proteins. A consensual IgE-binding epitope occurring in other plant nsLTP and responsible for some IgE-binding cross-reactivity among fruit nsLTP has been identified and characterized. Despite some discrepancies, a fairly good prediction resulted in applying our combination of predictive methods to longer nsLTP or plant profilins.

Amino Acid Sequence↗
PubMed2005

[Therapeutic management of asthma].

Therapeutic management of asthma is based on the key role of lower airway inflammation. New treatments and inhalation devices in conjunction with international recommendations have contributed to improve asthma management. The aim of asthma treatment is to avoid acute asthma and to reduce or suppress symptoms, to permit normal life (familial, scholar or professional) and to normalize lung function. The final goal is to improve patient quality of life and must also integrate the benefice/risk ratio of treatment. Asthmatic patients need to be regularly followed by a physician. Recently, French Anaes recommendations suggested to base the medical follow up on asthma control checking. Beside treatment of chronic asthma, acute asthma remains a potential emergency that needs to be rapidly identified and treated, following strict rules of clinical management.

Administration, Inhalation↗
PubMed2005

Diagnostic management of pulmonary embolism using clinical assessment, plasma D-dimer assay, complete lower limb venous ultrasound and helical computed tomography of pulmonary arteries. A multicentre clinical outcome study.

The objective of the study was to assess the clinical validity of a non-invasive diagnostic strategy for acute pulmonary embolism using clinical assessment combined with both ELISA D-dimer and complete lower limb ultrasound (US) examination of proximal and distal veins, before single-detector helical computed tomography (CT) of pulmonary arteries. We expected the strategy to have a high diagnostic exclusion power and to safely decrease the number of CT scans. This prospective, multicenter outcome study included 274 consecutive outpatients. All underwent a priori clinical probability, D-dimer and bilateral complete lower limb US assessments. Only patients with a high clinical probability and both tests negative, or positive D-dimer and negative US assessments, underwent CT. This was deemed necessary in 114 patients (42%). At baseline, venous thromboembolism (VTE) was detected in 110 patients (40%), either by US showing proximal (n=65) or distal (n=36) thrombosis, or by CT (n=9). Anticoagulant was withheld in the remaining patients with negative results in both D-dimer and US but a non-high clinical probability (n=59), or in both US and CT (n=90), or with negative US (n=6) and inadequate CT (n=9). All patients underwent a three-month clinical follow-up. VTE occurred in one patient with inadequate CT, yielding an incidence of 0.6% [95% confidence interval: 0.1-3.4]. No patient died from VTE or had major bleeding. Using clinical probability, ELISA D-dimer and complete US before helical CT is a safe strategy resulting in a substantial reduction in CT scans.

Adolescent↗
PubMed2005

[Sleep apnea syndromes and cardiovascular disease].

Sleep-disordered breathing is very common and is associated with an increased risk of cardiovascular disease, cardiac arrhythmia and stroke. There are two types of sleep apnea: obstructive and central. The objective of this review is to provide a broad perspective of the pathophysiological and clinical aspects of the two types of apnea and to discuss their cardiovascular adverse effects. The diagnosis of sleep apnea syndrome is based on polysomnography, and severity is measured with an apnea-hypopnea index that counts the total number of apneas per hour of sleep. Recent large epidemiologic studies have shown that sleep apnea affects about 16% of men and 5% of women between 30 and 65 years of age. Obstructive sleep apnea is characterized by abnormal collapse of the pharyngeal airway during sleep, snoring, vigorous inspiratory efforts causing frequent arousal, and excessive daytime drowsiness. Central sleep apnea with Cheyne-Stokes respiration is a form of periodic breathing with frequent periods of hyperventilation, and carries a poor prognosis in patients with heart failure. Obstructive apnea can also have substantial health consequences. Although the exact mechanism linking sleep apnea with cardiovascular disease is unknown, there is evidence that obstructive apnea is associated with a group of proinflammatory and prothrombic factors that are also important in the development of atherosclerosis. Nocturnal and daytime sympathetic activity is elevated after sleep apnea. Autonomic abnormalities include an increased resting heart rate, decreased cardiac rhythm activity, and increased blood pressure variability. Obstructive apnea is associated with endothelial dysfunction, increased C-reactive protein and cytokine expression, elevated fibrinogen levels and decreased fibrinolytic activity. Enhanced platelet activity and aggregation, leukocyte adhesion and accumulation of endothelial cells are common in both obstructive apnea and atherosclerosis. Surges in sympathetic activity, blood pressure, ventricular wall tension and afterload adversely affect ventricular function. Many studies have shown that patients with obstructive apnea have an increased incidence of daytime hypertension, and this syndrome is recognized as an independent risk factor for hypertension. Obstructive apnea is associated with myocardial ischemia (silent or symptomatic), acute coronary events, stroke and transient ischemic attacks, cardiac arrhythmia, pulmonary hypertension and heart failure. Central sleep apnea is frequent in severe heart failure. Most heart failure patients with pulmonary congestion chronically hyperventilate because of stimulation of vagal irritant receptors and central and peripheral chemosensitivity. When PaCO2 falls below the threshold required to stimulate breathing, the central drive to respiratory muscles and air inflow ceases and central apnea ensues. Apnea, hypoxia, CO2 retention and arousals provoke elevated sympathetic activity, increased afterload and elevated left ventricular transmural pressure, and promote the progression of heart failure. Tentative relationships have been identified between central apnea and markers of inflammation, oxidative stress and endothelial dysfunction. Recent mid-terms trials showed that nocturnal use of positive airway pressure in patients with the two types of apnea alleviates symptoms, reduces sympathetic activity, improves ventricular function and quality of life, and reduces daytime drowsiness. More studies are needed to understand the mechanisms underlying the relationship between sleep apnea and cardiovascular disease, but clinicians should be aware of this link and should attempt to identify patients with these syndromes.

Adult↗
PubMed2004

Diagnostic performance of complete lower limb venous ultrasound in patients with clinically suspected acute pulmonary embolism.

A limited ultrasound (US) confined to the popliteal and femoral veins is usually performed to detect deep vein thrombosis (DVT) in patients with clinically suspected acute pulmonary embolism (PE). Our objective was to assess the diagnostic accuracy of complete lower limb US examining both the proximal and distal veins in this setting. In this prospective study, 210 consecutive patients were included. Complete US was performed by independent operators and compared blindly with a reference strategy combining clinical probability, ventilation perfusion scan and pulmonary angiography to a three-month clinical follow-up. Simultaneously, VIDAS D-dimer (DD) assay and helical computed tomography (HCT) of the lungs were assessed independently and blindly. PE was present in 74 patients (35%). Complete US detected DVT in 91 patients (43%), proximal in 51 and distal in 40. Sensitivity and specificity with a 0.95 confidence interval were respectively 0.93 [0.85 - 0.97] and 0.84 [0.77 - 0.89]. Limited US detected DVT in only 46 patients (22%). Sensitivity and specificity were respectively 0.55 [0.44 - 0.66] and 0.96 [0.92 - 0.98]. For DD they were 0.92 [0.83 - 0.96] and 0.24 [0.17 - 0.32] and for HCT 0.84 [0.73 - 0.90] and 0.87 [0.80 - 0.92]. Complete lower limb US has higher sensitivity and capacity to exclude PE than limited US, but a slightly lower specificity. Complete US results also compared favourably with those of HCT and DD. The utility of including this method in diagnostic strategies for PE needs to be assessed in cost-effectiveness analysis and in outcome studies.

Angiography↗
PubMed2003

Limited operation for severe multisegmental bilateral bronchiectasis.

BACKGROUND: Some patients exhibiting severe multisegmental bilateral bronchiectasis are no longer improved with antibiotic treatment and drainage and, most of the time, operation is contraindicated. In our institution, limited operation has been offered to select patients for this indication. We report our data regarding the feasibility and utility of such a procedure. METHODS: We studied 16 patients who underwent surgical removal of nonlocalized disease between 1990 and 1999. We report the mortality and morbidity rates of this surgical procedure and the clinical, bacteriological, and functional data for each patient. RESULTS: There was no mortality and the morbidity was low (18%, all with favorable outcome). Symptoms such as hemoptysis, sputum production, or dyspnea were also improved. The recurring infections decreased in frequency in 8 patients and disappeared completely in 5 others. The bacteriological data assessment revealed disappearance of germs in 4 patients and persistence of chronic colonization in others. Postoperative spirometric data were not worsened and postoperative computed tomographic scans did not show progression of lesions not removed. CONCLUSIONS: These results suggest that, in properly selected patients, lasting symptomatic improvement can be achieved by resection. Limited operation may be indicated in nonlocalized bilateral bronchiectasis, provided that a target can be identified. This procedure is supported by physiopathologic arguments and is particularly relevant to patients with bronchiectasis with cystic and functionless territories.

Adolescent↗
PubMed2002

Endovascular treatment of aberrant systemic arterial supply to normal basilar segments of the right lower lobe: case report and review of the literature.

We report the case of a 17-year-old man with acute chest pain due to a partial thrombosis of a pseudosequestration. Unlike a true sequestration, there was a normal bronchial distribution and the involved lung parenchyma was normal on CT scan. A therapeutic transarterial embolization of the aberrant systemic artery from the proximal abdominal aorta was performed successfully. The patient did not suffer from further chest pain during the follow-up of 12 months. A contrast-enhanced CT scan 4 months later demonstrated complete occlusion of the embolized aberrant artery. Our case represents an alternative treatment to surgery for this rare abnormality.

Adolescent↗
PubMed2002

Large cell neuroendocrine carcinoma of the lung: pathological study and clinical outcome of 18 resected cases.

Large cell neuroendocrine carcinoma of the lung (LCNEC) has been recently redefined by the World Health Organisation (WHO) classification but the appropriate treatment remains unclear. We reviewed 18 consecutive resected cases of LCNEC. Two pathologists assessed diagnosis by applying rigorously the last WHO criteria. We reported the pathological features and the clinical outcome of this particular tumour. All patients were men with a median age of 63 years. Clinicopathologic stages corresponded to stage I (n = 8), II (n = 8) and IIIA (n = 2). All patients were treated as non-small cell lung carcinoma (NSCLC) and underwent surgery without any adjuvant treatment except four post-operative radiotherapy for N2 or T3 disease. The evolution was pejorative for 14 patients: one patient died of post-operative complications and 13 patients relapsed with distant metastases that occurred in 10 cases within 6 months after surgery. One-year survival rate was 27% and survival rate at the end of follow-up was 22%, which were both less than expected for stage-comparable NSCLC. Survival was neither influenced by lymph node status nor by pathological or molecular findings. Among the 10 evaluable patients with metastatic disease that received palliative platin-etoposide chemotherapy only two had partial tumour regressions (20%). Our study suggests that applying to LCNEC the NSCLC standard treatment lead to poor prognosis even in localised disease with a high incidence of early metastatic spread and a low response rate to chemotherapy. This way of relapse underlies the necessity of an efficient chemotherapy in order to improve survival.

Antineoplastic Combined Chemotherapy Protocols↗