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J Bignon

Publications and source records attributed to J Bignon.

At least 127 records · Page 7Linked to original sources
PubMed1984

Early cellular and biochemical alveolar responses following intra-tracheal inoculation with low dose of asbestos and quartz.

The study of broncho-alveolar lavage harvested from rats intratracheally dusted with chrysotile (0.5 mg), leached chrysotile (0.5 mg), crocidolite (0.5 mg) and quartz (0.5 and 5 mg) indicated: 1. A cytotoxic lysis of alveolar macrophages in relation to phagocytosis of dust particles in the following decreasing order: quartz, crocidolite, chrysotile. 2. Regarding cell intensity and duration while asbestos, even leached chrysotile, gave merely an early and transient response. This cell recruitment concerned mostly PMN leukocytes and at a less extent alveolar macrophage. 3. Cell recruitment was associated with an increased protein and phospholipids alveolar content. The increase of proteins came probably mostly from an inflammatory serum exudation. However, an increase synthesis of complement C3 and phospholipids is not excluded.

Animals↗
PubMed1984

Biological effects of New Caledonia nickel ore samples on red blood cells, alveolar macrophages and pleural mesothelial cells.

To examine the toxicity of three nickeliferous ores (Noumea Mines, Société le Nickel, in vitro tests were carried out with mammalian cells: haemolysis of human red blood cells (RBC), release of enzymes by rabbit alveolar macrophages (AM) for studying inflammation, and study of rat pleural mesothelial cells (PMC) to determine the effect on cellular growth and genotoxic effects.

Animals↗
PubMed1983

[Mesothelioma].

Explore the source record for details and available documents.

Humans↗
PubMed1983

Effect of chrysotile and crocidolite on the morphology and growth of rat pleural mesothelial cells.

The effects of the UICC asbestos fibers chrysotile A and crocidolite on the morphology and growth of rat pleural mesothelial cells were examined. The response was different according to the fiber used. Within 4 hr of treatment with 5, 10, 20, or 50 micrograms/ml of chrysotile fibers, cell morphology showed intense vacuolization, in both logarithmic and confluent cells. Following treatment of growing cells with 20 or 50 micrograms/ml of chrysotile fibers, cell spreading was also observed. Four hours after treatment of cells with 5, 10, or 20 micrograms/ml of crocidolite fibers, no such changes were seen. Vacuolization appeared later and was much less marked than for chrysotile fibers. The mesothelial cell population-doubling time of about 30 hr was not significantly altered by addition of 5 to 20 micrograms/ml of crocidolite fibers, but a concentration of 50 micrograms/ml lengthened doubling time to about 90 hr. Treatment with 5 or 10 micrograms/ml chrysotile fibers usually prolonged this time, but 20 or 50 micrograms/ml caused cell lysis. After 48 hr of incubation with both types of fiber, the proportion of mitosis was the same as in control cultures, whatever the fiber concentration, and asbestos fibers were often seen inside dividing cells.

Animals↗
PubMed1983

Mechanism of haemolysis by chrysotile fibres.

Haemolysis by chrysotile fibres may be related to an adsorption of the red blood cell (RBC) membranes on the fibres and not to an interaction between magnesium (Mg) from the fibres and sialic acid from RBC. This was demonstrated using neuraminidase (NANASE)-treated RBC and Mg-depleted chrysotile fibres. The mechanism may be extended to other minerals since a relationship can be obtained between the ability of various minerals to adsorb liposomes of dipalmitoyl phosphatidylcholine (DPPC) and their haemolytic activity.

Adsorption↗
PubMed1983

Incidence of various types of thoracic malignancy induced in rats by intrapleural injection of 2 mg of various mineral dusts after inhalation of 222Ra.

After inhalation of 222Ra at equilibrium with radon daughters, male Sprague-Dawley rats were inoculated intrapleurally with 2 mg of unleached or acid-leached asbestos fibres or glass fibres or quartz. The additive co-carcinogenic effects of this type of insult were demonstrated by the increased incidence of malignant thoracic tumours. In rats given mineral materials, bronchopulmonary carcinomas and mixed carcinomas were observed, as well as typical mesotheliomas and combined pulmonary pleural tumours, whereas in control rats inhaling radon alone, only bronchopulmonary carcinomas occurred. No significant differences in tumour incidence were observed between the groups of animals given the different types of dusts, but statistically significant differences were noted in survival times, according to the histological type of tumour. The co-carcinogenic effects of an insult of the pleura by mineral dusts following inhalation of radon are discussed in relation to a possible tumour-promoting effect by these agents.

Animals↗
PubMed1983

Comparative toxicities of different forms of asbestos on rat pleural mesothelial cells.

The effects of UICC crocidolite and chrysotile A, either oxalic acid-leached or unleached, on the viability, morphology and growth characteristics of rat pleural mesothelial cells (PMC) were examined; DQ12 quartz particles were also used. When asbestos fibers were added for 48 hr at the beginning of exponential growth, 20 or 50 micrograms/mL of chrysotile fibers were cytotoxic and no growth occurred; with 5 or 10 micrograms/mL a latent period was observed, and the mean population doubling time was increased. Chrysotile ingestion was associated with morphological changes (spreading, intense vacuolation); moreover, a large proportion of the cells was binucleated (more than 30% with 10 micrograms/mL). The oxalic acid-leached chrysotile inhibited growth at a concentration of 50 micrograms/mL; with 5 or 10 micrograms/mL, no spreading occurred, but a shrinkage of some cells was observed. A few large vacuoles were seen in the cytoplasm of the cells; there were fewer binucleated cells. Addition of 5 or 10 micrograms/mL of crocidolite, either leached or unleached, did not significantly change the growth rate, in spite of the presence of a large number of fibers inside the cells which persisted when the cells reached confluency. With 20 or 50 micrograms/mL, the mean population doubling time was increased in a dose-dependent manner. A slight vacuolation of the cells occurred. The sample of quartz did not modify the parameters studied in this report. The results confirm the different in vitro reactivities of the two kinds of unleached asbestos fibers. Leaching of chrysotile fibers decreased their reactivity; alternatively, leaching of crocidolite increased the effects on PMC.

Animals↗
PubMed1983

Studies on in vitro chrysotile-pleural mesothelial cell interaction: morphological aspects and metabolism of benzo-3,4-pyrene.

Cultures of rat pleural mesothelial cells (PMC) were exposed to nonlethal doses of UICC chrysotile A. The morphology was studied by optical and electron microscopy. The consequences of chrysotile ingestion on the rate of pinocytosis of horseradish peroxidase (HPR) metabolism and benzo-3-4-pyrene (BP) were studied. Nonlethal doses of chrysotile (5 micrograms/mL) induced a time-dependent vacuolation of PMC; a dose-dependent inhibition of the vacuolation was observed when PMC were pretreated with DMSO. The origin of the vacuoles is not clear, but some features of autophagy and lysosomal storage were observed. Chrysotile fibers did not modify the rate of pinocytosis of HRP. Similarly, the metabolism of BP was unchanged when BP and chrysotile were both added to the culture medium or when PMC were preincubated with the fibers 24 hr prior to the addition of BP.

Animals↗
PubMed1983

Biological in vitro and in vivo responses of chrysotile versus amphiboles.

Although all commercial forms of asbestos have been demonstrated to be carcinogenic in animals, so far epidemiological data are controversial concerning what asbestos types are the most carcinogenic and fibrogenic in humans. In order to understand the early cellular events induced by fibrous particles, different in vitro studies (hemolysis, release of enzymes by macrophages, assays on cell culture systems) have been carried out in several laboratories; most of these studies have shown that cell and subcellular in vitro responses were different depending on fiber types: chrysotile versus amphiboles. This presentation compares the results of different laboratories with our data obtained by using a model which modifies the chemistry of the fibers by acid treatment. The acid-leached chrysotile and acid-treated amphibole fibers showed different biological responses in several in vitro systems used in comparison to unleached fibers. These differences in the in vitro reactivity were related to the chemical state of the fibers and might explain the differences in their effects in animals after intrapleural injection as assessed by the percentage of mesothelioma, the latency period, the survival time and the degree of pleural fibrosis. The carcinogenic effect of the fibers is discussed in relation of their in vitro inflammatory or cytotoxic responses.

Animals↗
PubMed1983

[Pulmonary fibrosis and inorganic particles].

Biological data acquired in recent years has thrown new light on the pathogenesis of pulmonary fibrosis. The key element in the genesis of fibrosis may be the alveolar macrophage which, under the influence of different stimuli, secretes numerous factors, attracting polymorphonuclear leukocytes and eosinophils, stimulating fibroblasts and activating lymphocytes. Pulmonary fibrosis induced by inhalation of inorganic particles seems to proceed by identical mechanisms, with certain differences relating to the nature of each mineral. The morphological, cytological and immunological characteristics which defend the lung from silicosis and asbestosis are particularly discussed. The in vitro reactivity of several cell types (alveolar macrophages, mesothelial cells in culture, fibroblasts) equally has revealed differences between quartz and chrysotile. Nevertheless this in vitro response is difficult to interpret compared to an in vivo response: they vary according to the cellular system used and the physico-chemical state of the particular mineral (chrysotile and leached chrysotile by oxalic acid for example). The fibrosing action of other particles (talc, metals) is also reviewed. As opposed to an inflammatory granuloma secondary to the stimulation of alveolar macrophages which represents the usual response to mineral particles, there is also an immunological granuloma of the sarcoid type which may lead to secondary fibrosis: beryllium and talc in certain circumstances may act by this mechanism.

Animals↗
PubMed1983

[Multicenter study of a slow-release theophylline: armophylline].

In a co-operative study involving 10 centres, 95 asthmatic patients were treated with Armophylline, a new slow-release theophylline for a period of 1 to 3 months. Eighty per cent of the patients receiving the drug in doses of 11 to 15 mg/kg/day immediately had adequate blood theophylline levels (7-20 mcg/ml). There was a significant decrease in dyspnoea and number of asthmatic attacks and a significant increase in FEV1 and FEV1/VC ratio. The drug was usually well tolerated. Side-effects, such as insomnia, headache or digestive disorders were, as a rule, mild.

Asthma↗
PubMed1982

Indoor airborne asbestos pollution: from the ceiling and the floor.

Electron microscopic measurements of the concentrations of airborne asbestos were carried out inside and outside an office building having ceilings sprayed with a crocidolite-containing material and floors covered with vinyl-chrysotile tiles. Under normal conditions in this building, constructed 10 years ago, the two asbestos-containing materials released fibers into the air. This is the first measurement of elevated (up to 170 nanograms per cubic meter) concentrations of indoor airborne asbestos associated with the weathering of asbestos floor tiles during their service life. Asbestos flooring is used in a large number of buildings and represents the third largest use of asbestos fibers in the United States and in Europe, ranking after roofing and asbestos-cement pipe.

Air Pollutants↗
PubMed1982

[Asbestos pathology: clinical aspects epidemiological data and prevention].

The word "asbestos" is used to designate the main commercial types of asbestos (chrysotile, crocidolite, amosite) but there exist numerous asbestiform fibrous minerals, which are commercially valueless but widespread at the surface of the earth. Among them zeolite has already created health hazards in Turkey. Measurement of fibres in air and in tissues can contribute to a better knowledge of lung and body fibre burden associated with diseases. Among fibre-related diseases, studies have recently focused on clinical, epidemiological and pathogenic aspects of pleural fibrosis and lung or pleural cancer. At present the roles of the different types of fibres in the genesis of these diseases remain controverted. However, tobacco smoke associated with inhaled asbestos fibres provokes a multiplied risk of lung cancer. Regarding asbestos there exist regulations in most industrial countries designed to protect workers and diminish environmental pollution.

Air Pollution↗
PubMed1982

Features of asbestos-exposed and unexposed mesothelioma.

Thirty-six histologically confirmed cases of pleural and peritoneal mesothelioma have been observed in a chest unit over a period of 53 months. The past asbestos exposure was assessed by a standardized questionnaire in all cases and the asbestos lung burden was determined by means of mineralogical analysis of lung-related biological specimens (sputum, bronchoalveolar lavage fluid, lung tissues) in 28 cases. The results of these two methods were found in good agreement. Past asbestos exposure has been definitely implicated in 17 cases and definitely eliminated in 10 cases. The results were inconclusive in other cases. The group with definite past asbestos exposure was different from the nonasbestos-exposed group by clinical, biological, pathological, and prognosis features that were analyzed. In cases without past asbestos exposure there were no other possible causative agents. Younger age and similar incidence in men and women suggest an environmental or natural disease.

Adult↗
PubMed1982

Permeability of the blood-air barrier to antiperoxidase antibodies and their fragments in the normal rat lung.

The permeability of the blood-air barrier to antiperoxidase (HRP) IgG antibodies (160,000 daltons), F(ab')2 fragments (100,000 daltons) and Fab fragments (50,000 daltons) was studied in the normal rat. The use of isologous and heterologous immunoglobulin G or IgG fragments injected intravenously allowed a sequential study. It was shown that these proteins transfer from the vascular bed towards to interstitium. Evidence was obtained that these proteins crossed the endothelium through interendothelial spaces or structures suggesting transendothelial channels. The alveolar epithelium was found to be an efficient barrier for heterologous and isologous proteins, raising the question of the origin of serum proteins found in the alveolar surface material. Heterologous anti-HRP IgG antibodies and their Fab fragments were also administered intraalveolarly. The alveolar epithelium was found permeable to Fab fragments but not to IgG molecules, suggesting that some serum proteins present in the alveolar lining fluid can be transepithelially reabsorbed.

Animals↗
PubMed1982

PEEP-induced airspace overdistension complicating paraquat lung.

This report describes a case of paraquat poisoning, treated with continuous positive airway pressure. After an initial phase of acute respiratory failure with diffuse pulmonary edema, we observed radiologically a complete clearing of both lungs, associated with an aspect of overdistension. Surprisingly, FRC was above normal, as was total quasi static compliance. The patient died on the 15th day, with intractable hypoxemia. Pathologic analysis revealed large zones of parenchyma with overdistended airspaces, explaining the emphysematous-like aspect of the lungs. We propose that the attempts to increase lung volume with CPAP, at an early phase of diffuse epithelial disorganization, may have, partially at least, dilated the remaining distal airspaces.

Adult↗