Biomedical subjects
Publications and source records attributed to M C Jaurand.
Cultures were made of mesothelial cells obtained by scraping the parietal pleura of the adult rats. The growth was restricted to close polyhedric epithelial-like cells, forming a monolayer. The cellular proliferation continued until the 7th day, followed by a stationary phases. In subcultures the mesothelial cells kept their epithelial type. The cultures were stopped on the 20th day.
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Fibreoptic broncho-alveolar lavage was used in four patients; the diagnosis of histiocytosis X had been established by lung biopsy in three and was suggested on clinical grounds in the remaining patient. Characteristic cells with an ultrastructural cytoplasmic marker (X body) were found in the washes of all four patients. In the patient without biopsy confirmation, the findings in the broncho-aleolar washes supplied the corroborating evidence for the diagnosis. From this preliminary study the technique seems able to provide a diagnosis in pulmonary histiocytosis X without the need for an open lung biopsy.
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By means of antibodies labeled with horseradish peroxidase, autologous albumin and IgG were visualized in electron microscopy on the alveolar epithelial surface of the rat lung, as a continuous cell coat, as free granular deposits, or associated with tubular myelin figures. These 2 proteins were detected by immunochemistry in alveolar washing. After ultracentrifugation of alveolar washing, they were still found in the phospholipid-rich precipitate fraction by immunization of rabbits and by immunoelectron microscopy. Thus, albumin and IgG appeared as normal alveolar components in the rat lung; fibrinogen was not found under normal conditions.
Ultrastructural immunocytochemistry of plasma proteins and cytochemistry of polysaccharides with ruthenium red and concanavalin A were combined with different types of fixation with or without prior vascular or airway washing, to study the surface of capillary endothelial and alveolar epithelial cells of the blood-air barrier in the rat lung. The endothelial and epithelial cell surface layers were found to have two components: a moveable part belonging to the cellular microenvironement made of plasma proteins and a deeper glucidic or anionic fixed part bound to the plasma membranes (cell coat).
Counting coated and uncoated inorganic fibers in sputum has been used to investigate the level of environmental or occupational asbestos exposure and the concentration of fibrous dusts in human lung. Inorganic fibers in sputum were counted by light microscopy after chemical digestion and microfiltration processing. The same method was used for processing gastric juice and lung tissue. There were no ferruginous bodies (FB) in sputum from 49 patients without any asbestos exposure. The study of sputum from 125 patients with various asbestos exposure pointed out a high correlation between the number of FB in sputum and the level of asbestos exposure. These 125 patients were classified into three groups according to the type of their asbestos occupational hazard: group I, raw asbestos workers; group II, workers manufacturing asbestos products; group III, workers with mixed industrial dust exposure. For these three groups, the mean number of FB in sputum was 100, 10, and 1, respectively. The comparison of the FB content of sputum and lung parenchyma showed the absence of FB in sputum when the concentration of FB in lung parenchyma was under 1000/cm(3) of lung parenchyma; above this concentration the number of FB in sputum was in good correlation with fiber concentration in lung parenchyma. A preliminary study with the use of gastric juice showed that gastric juice is a less sensitive sample for evaluating fiber concentration in lung. The microfiltration method for the counting of uncoated fibers gave results as accurate as those in the centrifugation method.
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Natural mineral fibers may produce pulmonary cancers and mesothelioma. In contrast with lung cancer, the incidence of fiber-induced mesothelioma is not enhanced in smokers compared to non smokers. It is therefore of special interest to use mesothelial cells to study the toxicity of natural or man made mineral fibers. Several years ago, we have developed a method to culture rat pleural mesothelial cells (RPMC). We have first studied the effects of asbestos fibers by the application of in vitro tests formerly developed to determine the genotoxicity and transforming potency of soluble xenobiotics. Moreover, we have determined whether RPMC expressed cytochromes P450 known to metabolize polycyclic aromatic hydrocarbons. This paper reviews the results obtained so far. It has been found that asbestos fibers produced a cell transformation and a genotoxicity characterized by the formation of aneuploid cells, abnormal anaphases, chromosomal aberrations and DNA repair (UDS). In addition, RPMC expressed different forms of cytochromes P450. It is nowadays suggested that the tumorigenic potency of asbestos fibers may be related to the fiber dimensions, to their surface properties and in vivo biopersistence; this term involves the fiber solubility in biological medium and the fiber epuration from the lung by clearance mechanisms. Experiments are now in progress to determine whether the in vitro effects are dependent on the fiber parameters suggested as playing a role in the carcinogenic potency.
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