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Biomedical subjects

B Melloni

Publications and source records attributed to B Melloni.

At least 19 recordsLinked to original sources
PubMed1996

Effect of exposure to silica on human alveolar macrophages in supporting growth activity in type II epithelial cells.

BACKGROUND: The proliferative response of type II cells is an important event following silica-induced lung injury. Alveolar macrophages, when activated by fibrogenic agents, secrete various biological mediators which affect cell growth. METHODS: Human alveolar macrophages from normal volunteers were incubated in serum-free medium or in the presence of increasing concentrations of silica. Alveolar macrophage conditioned media were diluted and added to type II cell cultures for proliferation studies. Purified type II pneumocytes were isolated from fetal rat lungs for bioassays. Growth factor activities were partially characterised by size exclusion chromatography. Each fractionated mitogenic peak was preincubated with monoclonal antibody against platelet derived growth factor (PDGF) or antisera against insulin-like growth factor 1 (IGF-1) or fibroblast derived growth factor (FGF) in order to study the nature of each activity. RESULTS: Conditioned media from alveolar macrophages exposed to silica induced an increase in type II cell DNA synthesis and cell number over that seen when type II cells were incubated with unstimulated alveolar macrophage supernatants. Size exclusion of alveolar macrophage supernatants exposed to silica showed four peaks of type II cell stimulating activity with apparent molecular weights of 38, 22, 16, and 8 kDa. Anti-PDGF antibody significantly reduced the activity of the first and second peaks, antiserum against IGF-1 partially reduced the activity of the first and fourth peaks, and antiserum against FGF reduced only the third peak of activity. CONCLUSIONS: Human alveolar macrophages exposed to silica in vitro release mitogens for type II pneumocytes including PDGF-like, IGF-1-like, and FGF-like molecules. These agents are likely to be involved in the epithelial repair and type II cell hyperplasia observed in silicosis.

Adult↗
PubMed1996

Perindopril-associated pneumonitis.

We report two cases of perindopril-associated pneumonitis with typical drug-induced clinical features. In the first case, biopsies showed granulomatous sarcoid-like lesions; in the second, bronchial wall eosinophil infiltratf2p4was reported with increased blood eosinophil count. In these two cases, improvement was obtained by withdrawal of the drug and was completed with steroids. All other causes were ruled out. Angiotensin-converting enzyme inhibitor (ACEI)-induced pneumonitis is still rare but has to be recognized as a real side-effect.

Aged↗
PubMed1995

Work related distal airway obstruction in an agricultural population.

OBJECTIVE: To assess the prevalence of distal airway obstruction and its risk factors in agricultural areas. METHODS: A cross sectional study of respiratory symptoms and lung function was performed among French farmers and their spouses (1122 subjects) who came for preventive medicine examinations. They answered a respiratory questionnaire and performed pulmonary function tests on a portable spirometer. Diagnoses of chronic bronchitis were made on the basis of reported chronic respiratory symptoms. Airway obstruction was determined from predicted values. Odds ratio (OR) and linear regression coefficients were calculated after stratification by smoking and history of cardiac and other respiratory diseases. RESULTS: Of respiratory symptoms prevalence of chronic cough was 8.47%, and chronic bronchitis 7.66%. Prevalence of distal airway obstruction was 11.4%, and overall airflow obstruction 3.2%. Smokers were 20.2% men, and 5.7% women. Linear regressions showed high association between pack-years in smokers or exsmokers and forced expiratory volume in one second/forced vital capacity (FEV1/VC) and forced expiratory flow between 25% and 75% of vital capacity (FEF25-75). In non-smokers without any history of cardiac or respiratory diseases, age and the size of farms had the highest correlations with these variables. OR for distal airway obstruction was 2.1 in subjects > 50 years old v the younger ones and 3.02 in the smaller farms v the larger ones. CONCLUSION: After stratification by smoking and history of cardiac and respiratory diseases, distal airway obstruction is present in agricultural areas. The age, and the size of farm are the highest respiratory risk factors in non-smokers.

Adolescent↗
PubMed1995

Alterations of surfactant lipid turnover in silicosis: evidence of a role for surfactant-associated protein A (SP-A).

Type II cell hypertrophy with surfactant accumulation in the lung is a common observation in silicosis. Mechanisms leading to these alterations are poorly understood. By using silica dusts and alveolar fluids from saline and silica exposed sheep, we explored four different pathways of surfactant turnover in vitro: (1) synthesis and (2) secretion of lipids by rat type II cells; and dipalmitoylphosphatidylcholine (DPPC) uptake/reuptake by (3) type II cells and (4) alveolar macrophages. Silica had no direct specific effect on type II cell lipid metabolism. Alveolar fluids from both saline and silica exposed animals induced several alterations compared to control medium: (a) an increase in lipid synthesis (60 to 130%, P < 0.05); (b) a decrease in lipid secretion (25 to 70%, P < 0.05); (c) a 50 to 75% increase in DPPC reuptake by type II cells (P < 0.05); (d) a 65 to 75% decrease in DPPC uptake by alveolar macrophages (P < 0.05). DPPC uptake by in vivo silica exposed alveolar macrophages was reduced. Alterations of surfactant lipid metabolism induced by alveolar fluids from silicotic animals was more pronounced than in those treated with control fluids. Anti SP-A antibodies significantly suppressed most of the alveolar fluid induced effects on surfactant turnover. From these in vitro data, silica-induced type II cell hypertrophy seems to result from an increase in lipid synthesis activity and an imbalance in the lipid secretion/reuptake ratio.

1,2-Dipalmitoylphosphatidylcholine↗
PubMed1995

[Impact on the quality of life of respiratory symptoms and airway obstruction in an agricultural population].

Respiratory diseases are known to have consequences on health status. The objective of this study was to assess the quality of life of subjects with obstructive respiratory disorders coming for preventive medicine examinations. We conducted a study on a sample of adults living in agricultural areas (n = 1,235). We used two questionnaires: a respiratory questionnaire and the Nottingham Health Profile (NHP), which is a questionnaire designed to capture self-reported morbidity. It has been recently validated in french. Each subject performed a pulmonary function test on a portable spirometer to separate lung function obstructive abnormalities. Statistical analysis was realized by non parametric test. The number of positive responses (which shows bad health status) and the scores of the six dimensions are higher in females than males. According to sex and smoking habits, cough and chronic bronchitis are responsible for bad scores of health profile (for the total number of positive responses and the scores of each dimension). In case of airway obstruction, there is no major consequences on health profile. Subjective health measurements are interesting tools in subjects with non-chronic diseases. They can be associated with medical questionnaires because they give complementary inquiries.

Adolescent↗
PubMed1994

Partial characterization of the proliferative activity for fetal lung epithelial cells produced by silica-exposed alveolar macrophages.

The proliferation of lung epithelial cells is a prominent feature of lung tissue response following silica-induced lung injury and alveolar macrophages are recognized as a major contributing cell to the lung inflammatory processes. In previous studies, a growth-promoting activity for fetal rat lung epithelial cells was observed in silicotic alveolar fluids and in supernatants from in vitro and in vivo silica-exposed alveolar macrophages. In the present work, the biological and physicochemical properties of the macrophage-derived growth-promoting activity for fetal lung epithelial cells were explored. Four peaks of growth-promoting activity for lung epithelial cells ranging from 32 to 7 kDa were found in both in vitro and in vivo silica-exposed macrophage supernatants. The investigations were coupled with biochemical treatments of the mitogenic peaks and blocking antibodies or antisera were used to specify further the nature of the proliferative activities. Among the established growth factors, alveolar macrophage-derived growth fractions had characteristics consistent with platelet-derived growth factor-, insulin-like growth factor 1-, and fibroblast growth factor-like molecules. The cytokine production following in vitro exposure, which reflects very early events in the pathogenesis of silicosis, was more strongly related to the high-molecular-weight PDGF-like molecules, whereas the cytokine production following in vivo exposure, which reflects later events in the pathogenesis of silicosis, was more influenced by intermediate-molecular-weight FGF- and IGF-like molecules.

Animals↗
PubMed1994

[Pneumopathy induced by pirindopril. A case report].

Cough is known to be the major respiratory side effect of treatment with angiotensin converting enzyme inhibitors (ACEI). Recently, ACEI have been implicated in drug-induced lung disease. We report a new case of diffuse pneumonitis which occurred during treatment with ACEI. A 73-year-old man was admitted for cough, dyspnea at rest, fever and weight loss. The patient had been treated with the ACEI pirindopril during 6 months for systemic hypertension. Chest radiographs showed reticular infiltrates in the upper lung fields. A CT scan confirmed the infiltrates and showed pleural thickening and airspace opacities. White blood cell counts showed 15,700/mm3 leucocytes with 940 eosinophils/mm3. Transbronchial biopsy was consistent with infiltration of the lung with eosinophils. There was no evidence for another etiology. Once the drug was withdrawn, clinical and radiological abnormalities improved but steroids were required to control symptoms. This report suggests that pirindopril, as captopril, can induce the picture of drug-induced pulmonary disease.

Aged↗
PubMed1993

Silica-exposed macrophages release a growth-promoting activity for type II pneumocytes.

This study addresses the hypothesis that silica-activated alveolar macrophages could release soluble factors stimulating type II cell proliferation. Macrophages from control sheep were exposed or not in vitro to silica, aluminum-treated silica (Si-Al), or titanium dioxide (TiO2). In addition, macrophages from a model of chromic silica-exposed sheep were studied. Supernatants from unstimulated macrophages were found to double basal type II cell DNA synthesis. Alveolar macrophage-conditioned media (AMCM) collected from cells exposed in vitro to silica induced an additional growth-promoting activity for type II cells. Supernatants from Si-Al- or TiO2 dust-exposed alveolar macrophages had the same effects as unstimulated AMCM. In addition, AMCM from in vivo silicotic sheep cells also contained elevated levels of type II cell mitogenic activity. These results suggest that in vitro as in vivo, silica-activated macrophages produce a type II cell growth factor(s) for type II epithelial cells.

Animals↗
PubMed1993

Phospholipid content of bronchoalveolar lavage fluid in granite workers with silicosis in Quebec.

BACKGROUND: Some of the prominent features of silicosis are hyperplasia and hypertrophy of epithelial type II cells, which in experimental animals are often accompanied by accumulation of phospholipids in the lung. METHODS: The total phospholipid content of lung lavage fluid and its composition in 28 granite stone cutters with long term exposure to silica dust (23 with radiological silicosis) was compared with that of lavage fluid in 15 normal volunteers, 15 patients with untreated idiopathic pulmonary fibrosis, and 19 patients with untreated stage 2 or 3 sarcoidosis. All lavage fluid was obtained at the time of first pulmonary investigation, which also included lung function tests. RESULTS: In the normal subjects total phospholipid content was 1.13 (0.16) micrograms phosphorus/ml of lung lavage, in the patients with idiopathic pulmonary fibrosis 0.52 (0.07) microgram/ml (p < 0.05), and in the patients with sarcoidosis 1.02 (0.20) microgram/ml composition being in the range reported in humans. In the patients with silicosis total phospholipid content was significantly decreased to an average of 0.46 (0.08) microgram/ml compared with the findings in normal subjects and patients with sarcoidosis. Within the group exposed to silica changes in total phospholipid content did not correlate with the severity of the radiographic disease, changes in lung function, the cellularity of lung lavage fluid, or hyaluronate concentrations. The secretory capacity of rat epithelial type II cells was not significantly different when cultured with bronchoalveolar lavage fluid from all four groups of subjects. CONCLUSIONS: Total phospholipid content in lung lavage fluid was significantly reduced in granite workers with radiological evidence of lung disease, but showed no correlation with radiological or functional markers of disease severity.

Adolescent↗
PubMed1992

[Perceptions of consequences of chronic respiratory insufficiency in subjects over 65 years with home respiratory assistance. Apropos of 85 patients].

Chronic respiratory diseases (C.R.D.) induce changes in daily activities and mood for the patients who require respiratory assistance (oxygen delivery or ventilation). The aim of this study was to compare physical and social consequences of this disease. A self administered questionnaire was sent to one hundred patients, over sixty five years of age, who were affiliated with the "Association Limousine d'Aide aux Insuffisants Respiratories" (A.L.A.I.R.). The mean age was 72.4 +/- 0.66 (65-92), the mean PaO2 was 54 mm Hg +/- 0.2 (39-76). C.R.D. was stable during the study and treatments did not change. The questionnaire was composed of four scales and twenty-eight subjects; each item was weighed for importance. Subjects included: symptoms, mood, sleep, relationships with their wife or family, home activities. Eighty-five questionnaires were analysed. Reproductibility was good (92%) and non-responses to some questions was less than 10%. Coherence between the scales and the twenty-eight items was poor. Regression linear analysis found that only dyspnea was correlated with PaO2 (p < 0.007). For patients, the most important items were: abnormalities of home activities (37%), dyspnea (38%), relationships with their wife (39%) or family (45%), dependence (52%) and perception of A.L.A.I.R. (77%). Quality of life is an important concept for these patients with C.R.D. versus clinical symptoms. Perception of respiratory assistance is very good.

Activities of Daily Living↗
PubMed1992

[The influence of a new beta agonist: formoterol on mucociliary function].

The muco-ciliary apparatus has an essential role in the cleansing of the tracheo-bronchial tree of particulate matter. Disturbances linked to muco-ciliary function are well known in respiratory pathology and in cases of chronic bronchitis and asthma and lead to a reduced capacity for cleansing. In addition there are numerous pharmacological agents including sympathomimetics which are capable of altering the ciliary activity and the rheological properties of mucous. The role of Formoterol, administered as an aerosol has been assessed in vivo in 10 bronchitic patients who were in a stable state. After 6 days of treatment using the Formoterol aerosol the muco-ciliary clearance had significantly increased to 46% and was a real gain when compared to the muco-ciliary clearance measured on placebo. This gain was linked to a better function of the muco-ciliary carpet and not due to the bronchodilatation which was induced by Formoterol, because the penetration index did not change. At the same time the airway resistance was slightly reduced in a none significant fashion.

Administration, Inhalation↗
PubMed1991

[Tuberculosis and acute respiratory insufficiency. Apropos of 2 cases].

We report two cases of death from acute respiratory insufficiency of tuberculous origin. There were rare clinical presentations in which the clinical and radiological aspects were particularly atypical, suggesting a diagnosis of an acute respiratory distress syndrome. Bacteriological confirmation is necessary but it is worth considering this aetiology with each case of unexplained respiratory distress because the mortality is high and the prognosis is related to how early drug therapy is given.

Humans↗
PubMed1989

[Post-traumatic pulmonary hematomas. Apropos of 2 cases].

Post-traumatic pulmonary hematoma presents clinically as a hemorrhagic collection within a newly-formed cavity in the lung parenchyma. Its frequency is probably underestimated in view of the importance of the associated lesions. The most frequent clinical sign is hemoptysis. The chest radiograph, as well as the CT scan, shows a clearly defined round image. As a rule, there is a favorable outcome with slow resorption over several weeks, with a restoration of the integrity of the pulmonary parenchyma, which justifies simple observation, with an absence of any therapeutic intervention.

Adult↗