[French pulmonary specialists and the prevention of respiratory disease].
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Air Pollution↗
Biomedical subjects
C Voisin
Publications and source records attributed to C Voisin.
Electron-phonon scattering in metal clusters.
Electron-lattice energy exchanges are investigated in gold and silver nanoparticles with sizes ranging from 30 to 2.2 nm embedded in different environments. Femtosecond pump-probe experiments performed in the low-perturbation regime demonstrate a strong increase of the intrinsic electron-phonon interaction for nanoparticles smaller than 10 nm due to a confinement effect.
Journal Article↗
Ultrafast carrier dynamics in single-wall carbon nanotubes.
Time-resolved carrier dynamics in single-wall carbon nanotubes is investigated by means of two-color pump-probe experiments. The recombination dynamics is monitored by probing the transient photobleaching observed on the interband transitions of the semiconducting tubes. This dynamics takes place on a 1 ps time scale which is 1 order of magnitude slower than in graphite. Transient photoinduced absorption is observed for nonresonant probing and is interpreted as a global redshift of the pi-plasmon resonance. We show that the opening of the band gap in semiconducting carbon nanotubes determines the nonlinear response dynamics over the whole visible and near-infrared spectrum.
Journal Article↗
Photoluminescence up-conversion in single self-assembled InAs/GaAs quantum dots.
Microphotoluminescence measurements under cw excitation reveal the existence of a strong photoluminescence up-conversion from single InAs/GaAs self-assembled quantum dots and also from the InAs wetting layer. Excitation spectroscopy of the up-converted photoluminescence signal shows identical features from the wetting layer and the single quantum dots, i.e., a band tail coming from the deep states localized at the rough interfaces of the wetting layer quantum well. This observation of photoluminescence up-conversion demonstrates the influence on the quantum dot properties of the environment, and highlights the limitations of the artificial atom model for a semiconductor quantum dot.
Journal Article↗
[The pre-admission visit, or when the nursing team moves].
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Aged↗
Size-dependent electron-electron interactions in metal nanoparticles
The internal thermalization dynamics of the conduction electrons is investigated in silver nanoparticles with radius ranging from 13 to 1.6 nm using a femtosecond IR pump-UV probe absorption saturation technique. A sharp increase of the electron energy exchange rate is demonstrated for nanoparticles smaller than 5 nm. The results are consistent with electron-electron scattering acceleration due to surface induced reduction of the Coulomb interaction screening by the conduction and core electrons.
Journal Article↗
[Tuberculosis eradication: realist perspective or utopia?].
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BCG Vaccine↗
[Evaluation and symptomatic treatment of surinfectious exacerbations of COPD: preliminary study of antibiotic treatment combined with fenspiride (Pneumorel 80mg) versus placebo].
UNLABELLED: Exacerbations of chronic obstructive pulmonary disease (COPD) have an inflammatory component in addition to the possible infectious component. The antiinflammatory properties of fenspiride (Pneumorel(R) 80 mg) should be evaluated in this frequent clinical situation. OBJECTIVES: Assess the supplementary therapeutic benefit provided by fenspiride administered in combination with antibiotics in COPD patients presenting an episode of bronchial infection. PATIENTS AND METHODS: A preliminary randomized placebo-controlled double-blind study was conduced in 7 centers. Patients under 80 years of age of both sexes were included. All patients had COPD and presented a bronchial infection defined as the presence of at least 2 of the 3 criteria defined by Anthonisen. Patients were randomly assigned to group F or group P. Group F received an antibiotic therapy from day 1 to day 11 plus fenspiride (3 x 80mg/d from day 0 to day 30). Group P received the same antibiotic therapy plus placebo. Amoxicillin 500mg plus clavulanic acid 125, 3 tablets/day, was administered in both groups. RESULTS: Thirty-nine patients were included (group F 19 patients, group P 20 patients; 6 women and 33 men; mean age 61.1 +/- 9.8 years). The 3 Anthonisen criteria were present in 79% and 75% of the patients in group F and P respectively (NS). On day 11, expectoration resolved in 39% and 32% (NS) and cough in 44% and 16% (NS) of the patients in groups F and P respectively. Lung auscultation returned to normal in 83% of the patients in group F compared with 47% in group P (p=0.05). A composite clinical score including expectoration cough and auscultation findings showed that 28% of the patients in group F were symptom-free on day 11 compared with 0% in group P (p=0.04). On day 30, the two groups were comparable. CONCLUSION: In this preliminary study of patients with COPD presenting a bronchial superinfection, there was a significant improvement in lung auscultation and in the composite clinical score in patients given fenspiride. Fenspiride was thus found to provide an early clinical benefit.
Acute Disease↗
The hypoxaemia in chronic obstructive pulmonary disease (COPD) and its management.
Chronic hypoxaemia < or = 55 mmHg, induces various clinical and physiological consequences in patients with stable COPD: dyspnoea, decrease in exercise performances, erythrocytosis impairment of neuropsychological functions, pulmonary hypertension, right ventricular heart failure, all of these troubles impairing quality of life and vital prognosis. To restore a PaO2 > 60 mmHg (or SaO2 > 90%), long term oxygen therapy (LTOT) is the best method in the management of COPD with severe chronic respiratory failure. For patients with PaO2 55-70 mmHg. Almitrine bismesylate a piperazine derivative improving the ventilation/perfusion matching, used in low dosage and in sequential administration, is a useful drug to increase the PaO2 and so, to delay but not to avoid LTOT in responder patients when PaO2 remains < or = 55 mmHg.
Almitrine↗
[Medico-social management of severe respiratory insufficiency. Role of Associations].
Roughly 50,000 patients in France with severe chronic respiratory failure are under treatment with respiratory domiciliary support. Over 28,000 of these are managed by a non-profit associative network. These patients are of varied age with 7% under the age of 30 and 45.8% over 70 years. Likewise the causes and the treatment modalities are varied. Because of the technical constraints of respiratory support these patients have difficulties of a psychological and social nature which can lead to a substantial reduction in their quality of life. The medico-social management of the patient with respiratory failure involves firstly the education of the patient and his family or carers about the objectives and practicalities of the treatment. Secondly there is the objective of improving quality of life by inciting a continued level of activity, in order to avoid isolation and to maintain social contact. The possibility of increased mobility by the use of liquid oxygen together with respiratory rehabilitation programs leads to better effort tolerance and opens up new perspectives for these patients. The regional respiratory non-profit home care associations have an important role in these developments as they provide direct medical and technical as well as social and psychological support to the patient in his home, and also by the contacts formed with others involved in his care. The national association (ANTADIR) which federates the associations allows concerted effort and supports research of a medical, technical and socio-economic nature and promotes respiratory home care as well as forming a national Observatory which has collected data since 1984.
Adult↗
[Susceptible populations and urban atmospheric pollution. Development of a policy of protection].
The short term vulnerability of sections of the population to the harmful effects of chemical pollutants in the urban atmosphere represents an important unresolved problem of public health. These groups include young children, the elderly, asthmatic patients, and patients with chronic bronchitis and cardio-respiratory insufficiency. A recently ratified French law on air and rational energy use is aimed at resolving this problem in the context of recognizing that everybody has a right to breathe air which is not damaging to their health. In order to achieve this objective and direct the measures to be taken to reduce the emission of pollutants relating to industrial activity, to heating and to road traffic, the law provides for an extension to the chain of automatic registering stations which enable the recording of atmospheric data in large urban centers. It also defines the limits of substances allowed in the air over given periods and revises the critical levels of particulate and gaseous pollutants allowed according to current experimental and epidemiological data. Thresholds for information and for alerting the population will also be defined, with eventually restrictive measures for industry and for car traffic envisaged. These provisions are a major step for the protection of susceptible populations and should be enhanced in the near future by extension to cover other potentially noxious substances. This requires continued study on the short and long term effects of atmospheric pollution on people's health.
Air Pollution↗
Lungs exposed to nuclear catastrophe: one-year therapeutic programme in Chernobyl liquidators group.
The high prevalence of chronic respiratory problems in cleaning technicians (so-called "liquidators") of the destroyed reactor at Chernobyl and prolonged persistence of inhaled radioactive particles in their lungs suggested a substantial link between radioactive exposure and the diseases observed. Taking into account the importance of the problem, we started this study with the aim of establishing an effective and useful therapeutic program and assessing its efficacy during a one-year period of treatment. Chernobyl liquidators (n = 20) were screened by clinical history, physical examination, lung function test, chest radiograph, electrocardiogram, complete blood cell counts, serum chemistry, immunological blood tests, and complete BAL fluid investigation. One group of the patients (n = 10) underwent a special one-year treatment including polyvitamins, N-acetylcysteine, and therapeutic BAL every 3 months. The technique of therapeutic BAL has proven to be a promising and effective tool in the treatment of lung diseases induced by inhalation of radioactive particles.
Adult↗
Morphometry and densitometry of alveolar macrophage cytoplasmic particles in Chernobyl, Ukraine, liquidators.
OBJECTIVE: To characterize intracytoplasmic particles found in alveolar macrophages (AMs) sampled by bronchial alveolar lavage (BAL) performed on Chernobyl, Ukraine, liquidators suffering form chronic obstructive lung disease. STUDY DESIGN: Eight BALs were assessed. BAL products containing AMs were cytocentrifuged, and appropriate fixation and epoxy embedding were performed for ultrastructural study. Morphometry of cells (AMs) and of cytoplasmic particles was then obtained by processing, using dedicated software, digitized ultrastructural images. RESULTS: AM cytoplasm contained crowded phagolysozomes, varying in size, shape and density and enclosing dense particles rich in radionuclides, with particular morphometric features: surface, 387 +/- 543 pixels (mean +/- SD); number, 77 +/- 34; phagozome/cell surface ratio, 23.7%; shape factor, 1.32 +/- 0.23; and mean optical density, 171 +/- 31. CONCLUSION: Processing of digitized ultrastructural images of AMs provides accurate morphometric data that can be used further for clinical purposes, in particular to evaluate BAL performed either for diagnosis or treatment.
Adult↗
["Primary" diffuse interstitial fibrosis in coal miners: a new entity? Study Group on Interstitial Pathology of the Society of Thoracic Pathology of the North].
It is well known that silica exposure leads in an experimental model to the development of an acute fibrotic process. In human beings two main observations have already been done: (1) silica exposure is frequently associated with the development of connective tissue disease (CTD), especially progressive systemic sclerosis; (2) 10 to 20% patients with CTD developed pulmonary fibrosis. In this context we report 26 cases of coal miners who presented with clinical, radiological, biological and functional characteristics mimicking idiopathic pulmonary fibrosis (IPF), with or without associated coal worker's pneumoconiosis (CWP). All were men; mean age was 68 +/- 9.2 years. Twenty-three were smokers. Duration of exposure was 28.8 +/- 9.1 years. All the patients had dyspnea (stage III, IV in the NHYA classification) and diffuse crackles. Eleven out of 26 had finger clubbing. Computed tomography showed honeycombing (23 cases), and/or ground glass opacities (6 cases) with bronchiectasis (3 cases) predominant in the lower lobes; 19 had radiological signs of CWP, micronodules (n = 16) and nodules (n = 3) predominant in the upper lobes. BAL exhibited an increased % of neutrophils (11.9 +/- 16.1%). Lung function demonstrated a restrictive pattern (TLC = 73 +/- 15.6% and VC = 80 +/- 18% of predicted values) associated with a decreased DLCO (51.8 +/- 23.6% of predicted values) and hypoxemia (at rest = 66.5 +/- 11.2 mmHg, upon effort = 56 +/- 12 mmHg). Lung biopsies were performed in four cases and demonstrated interstitial fibrosis of intraalveolar septum with an accumulation of immune and inflammatory cells similar to the one described in IPF. The association between IPF and silica exposure with or without associated CWP points out the problem of legal recognition of idiopathic-like pulmonary fibrosis as a complication of the occupational exposure of coal workers.
Adult↗
Mineralogical analysis of the respiratory tract in aluminium oxide-exposed workers.
A retrospective study was conducted in order to characterize the retention of fibrous and nonfibrous mineral particles in the respiratory tract in subjects with previous occupational exposure in the aluminium industry. Bronchoalveolar lavage (BAL) fluid (three samples) or lung parenchyma (two samples) were studied using analytical transmission electron microscopy in five patients. A high concentration of aluminium fibres (> 10(7) fibres.g-1 dry lung) was identified in two lung tissue samples, and aluminium fibres were also identified in BAL fluid in three patients. All fibres were short (mean length: 1-2 microns), with no fibre longer than 5 microns. Some biopersistence of these fibres in the respiratory tract is suggested from these observations, since fibres were identified in biological samples collected more than 4 yrs after cessation of exposure in four out of five patients. Occupational physicians should be aware of possible exposure to short, thin aluminium fibres during primary aluminium production. Further studies are needed to assess the potential health effects of these fibres. Industrial hygiene measurements should also be performed to document the potential sources of exposure to aluminium fibres in this industry.
Adult↗
[The morphological characteristics of the alveolar macrophages in those who cleaned up the aftermath of the accident at the Chernobyl Atomic Electric Power Station at a late period (1)].
The paper presents morphological, morphometric and densitometric evidence obtained on cytoplasmic inclusions of alveolar macrophages from bronchoalveolar lavage of chronic obstructive bronchitis (COB) sufferers. All of them previously worked in the zone contaminated after the Chernobyl accident. The control consisted of nonexposed to radiation COB patients. In the exposed subjects alveolar macrophages were more active, 20% of cytoplasm was occupied by numerous phagolysosomes varying in form. Their densitometric evaluation has been performed. Further bronchoalveolar lavages will be conducted to follow up the above changes in alveolar macrophages.
Adult↗
The delayed respiratory consequences of inhaled radionuclides in population exposed to nuclear catastrophe.
Cytological analysis of bronchoalveolar lavage (BAL) and x-ray energy dispersive spectrometry of intercellular compounds were evaluated in 19 workers ("liquidators") commissioned to clean and contain the nuclear waste after the Chernobyl catastrophe in comparison with ten control subjects. Results showed a significant increase of neutrophils, small monocyte-like alveolar macrophages (AM) and AM with large black cytoplasmic inclusions. In addition, such mineral elements as Zr, Ce, Pr, Sm, Pa, PU and Cs were detected in AM phagosomes in liquidators. These elements were reported as markers of Chernobyl-type nuclear fuel. It is recognized that BAL gives access to particulate matter present in lung parenchyma. Thus, spectrometric analysis of AM inclusions can provide reliable information about the exposure to inhaled radionuclides seven years after the catastrophe.
Administration, Inhalation↗
Secretion and mRNA expression of TNF alpha and IL-6 in the lungs of pneumoconiosis patients.
Exposure to coal-mine dust leads to coal workers' pneumoconiosis (CWP), characterized by the development of a perifocal and progressive fibrotic reaction. In order to confirm their in vivo participation in the pathogenesis of CWP, the expression of tumor necrosis factor (TNF) and interleukin-6 (IL-6) was evaluated in bronchoalveolar lavage (BAL) specimens collected from 12 patients with simple pneumoconiosis (SP) and six with progressive massive fibrosis (PMF), and in pulmonary tissue from one patient with SP and three with PMF. Expression of TNF and IL-6 was assessed using both in situ hybridization and immunohistochemistry. The number of positive cells found in BALF was significantly higher for patients with PMF (TNF = 55 +/- 6%; IL-6 = 46 +/- 12.8%) than for those with SP (TNF = 34 +/- 11.6%; IL-6 = 26 +/- 10.2%) or normal controls (TNF = 15 +/- 5.5%; IL-6 = 13.3 +/- 6%), and was correlated with cytokine concentrations in supernatants from alveolar macrophages (AM). In lung biopsies, the expression of messenger ribonucleic acid (mRNA) for TNF was associated with the presence of coal dust and was limited to lung macrophages; mRNA for IL-6 was detected in mononuclear phagocytes but also in other types of cells such as endothelial cells. Monokine synthesis was confirmed by immunohistochemistry. These data confirm that TNF and IL-6 production is increased in the lungs of pneumoconiotic patients. Moreover TNF and IL-6 expression was associated with the presence of coalmine dust particles, suggesting a direct role of mineral particles in the cytokine production and development of pneumoconiotic lesions in CWP.
Adult↗