Biomedical subjects

M C Jaurand

Publications and source records attributed to M C Jaurand.

At least 91 records · Page 5Linked to original sources

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↗

PubMed1981

Rat pleural mesothelial cells in culture.

A culture system has been developed for long-term maintenance of rat pleural mesothelial cells. Mesothelial cells were isolated from the parietal pleura of rats and cultured in NCTC 109 medium supplemented with 10% fetal bovine serum. The cell explants attached to the dish and formed a confluent monolayer of polygonal cells within 10 to 15 days. Subcultures were made in the same medium. The mean population doubling time was approximately 30 hr. The ultrastructure of the mesothelial cells in culture was studied by light and electron microscopy and was compared with that of cells obtained from sub-mesothelial components.

Animals↗

PubMed1981

In vitro reactivity of alveolar macrophages and red blood cells with asbestos fibres treated with oxalic acid, sulfur dioxide and benzo-3,4-pyrene.

The effects of 3 UICC asbestos fibres (A chrysotile, crocidolite, amosite) were observed in vitro on red blood cells (RBC) and alveolar macrophages (AM). THe reactivity of the fibres after leaching with 0.1 N oxalic acid or adsorption of SO2 or benzo-3,4-pyrene (BP) was studied. The haemolytic activity of crocidolite and amosite was very low. A cytotoxic effect on AM occurred when the fibres were present in high concentration (100 microgram/ml), this was characterized by a release of both cytoplasmic (LDH) and lysosomal (beta-galactosidase) enzymes. The leached fibres were more haemolytic than the unleached ones, and more beta-galactosidase (beta-Gal) than lactic dehydrogenase (LDH) was released from the AM. In contrast to the amphiboles, chrysotile fibres were highly haemolytic and induced a selective release of beta-Gal from AM. Leached fibres were less haemolytic and were cytotoxic for AM (both enzymes were released). Their in vitro reactivity was similar to that observed with quartz. The results showed that SO2 changed the reactivity very little. BP sorption on acid-leached chrysotile decreased the LDH release from AM. The difference in the in vitro reactivity related to the chemical state of asbestos fibres might explain the difference in their in vivo reactivity (latency, degree of fibrosis). This point is discussed.

Animals↗

PubMed1981

Mesotheliomas in rats following inoculation with acid-leached chrysotile asbestos and other mineral fibres.

The carcinogenicity of untreated UICC chrysotile A, of acid (oxalic and hydrochloric)-leached UICC chrysotile A, of crocidolite and of JM 104 glass fibres has been studied by intrapleural injection into rats. This experiment, carried out on 304 animals, demonstrated that when more than 80% of the Mg had been leached from chrysotile fibres by either hydrochloric or oxalic acid, the proportion of pleural mesotheliomas was either nil or dramatically lower than that obtained with untreated chrysotile. The carcinogenic effect of crocidolite was higher than that of 43.7% oxalic acid-leached chrysotile. The proportion of mesotheliomas observed in animals injected with JM 104 glass fibres was similar to that in animals injected with fibres from which 63.8% had been leached with oxalic acid. These results indicate that with regard to the induction of pleural carcinogenicity by chrysotile fibres, not only size characteristics but also parameters such as chemical composition and physiochemical properties must intervene.

Animals↗

PubMed1980

Chemical and photoelectron spectrometry analysis of the adsorption of phospholipid model membranes and red blood cell membranes on to chrysotile fibres.

A study of the interaction of phospholipid model membranes and red blood cell membranes with UICC A chrysotile fibres using chemical analysis and photoelectron spectrometry showed that the interaction agreed with an adsorption of the membranes on to the chrysotile fibres. The photoelectron spectrometry analysis allowed the statement that phospholipid model membranes are adsorbed as bilayer. Chemical analysis showed that for each milligram of chrysotile the amount of phospholipids adsorbed was about 155 microgram and the available surface for phospholipids was about 38 m/g. It was established that entire membranes were adsorbed. A mechanism for the haemolytic capacity of chrysotile is suggested.

Adsorption↗

PubMed1980

[Reaction of the interior lobes of the lung to the inhalation of mineral fibers].

Exposure to airborn fibres is an important health problem in man. Asbestos fibres (chrysotile, amphiboles) are the most frequently used; but, recently the same health problems were observed with other fibres (zeolite, glass fibres). The effects of inhaled fibres at the level of the respiratory system are related to the types of fibres and to the penetration and biological reactivity into the alveolar spaces. Two types of diseases can be observed: lung and pleural fibrosis and lung and pleural cancer. Actually, the size of fibres is a major point for these effects, the longest and thinnest fibres being the most dangerous. However, recent data with acid treated chrysotile indicate that the chemical composition must also intervene.

Asbestosis↗

PubMed1980

[Biological activity of fibers in vitro and in vivo].

Understanding of the biological effects of fibres has been archievied due to a large number of in vitro (cytotoxicity on free cells) and experimental studies. However, the basic mechanisms are still unknown. Results showed that fibres act on various levels, nuclear, metabolic, immunologic or molecular.

Animals↗

PubMed1980

Effects of well-defined fibres on red blood cells and alveolar macrophages.

The fibres used in this experiment were UICC asbestos fibres (chrysotile, amosite, crocidolite, either untreated or leached with oxalic acid), nemalite and glass fibres. Chrysotile was also treated with sulfur dioxide. Size distribution measurements by electron microscopic analysis, chemical analysis and measurement of specific surface area were performed. Haemolytic activity was studied in human red blood cells by kinetic analysis of the percentage of haemoglobin released; this generated information on the shape of the curve, the initial velocity of the haemolysis and the maximal haemolysis. The effect on rabbit alveolar macrophages was determined in vitro by the measurement of lactic dehydrogenase and beta-galactosidase released from alveolar macrophages cultured with the fibres. Amphiboles and chrysotile had opposite reactivities on red blood cells. Leaching did not change the shape of the curve with chrysotile whereas it modified that with amphiboles. The initial velocity decreased with leached chrysotile and increased with leached crocidolite or amosite. Maximal haemolysis was linearly dependent on the fibre concentration with amosite and crocidolite, but not with chrysotile or nemalite. The adsorption of sulfur dioxide onto chrysotile did not highly modify its haemolytic activity. In alveolar macrophages, chrysotile and leached amphiboles selectively released beta-galactosidase; and leached chrysotile and nemalite released both enzymes studied.

Animals↗

PubMed1980

Surface interaction between chrysotile and solutions (dissolution and adsorption): systematic x-ray photoelectron spectroscopy studies.

To test the reactivity of asbestos in relation to its physical and structural properties, surface analysis was made by X-ray photoelectron spectroscopy. The dissolution kinetics of chrysotile in strong reagents demonstrate two rate-limiting steps for the reaction: Mg2+ diffusion and chemical reaction. In some components of the Krebs cycle and in dilute hydrochloric and in oxalic acids, the reaction is limited by the exchange of Mg2+ in the first mineral layer. The interaction of model phospholipid membranes with chrysotile fibres was also studied; the results are in good agreement with the hypothesis of bilayer adsorption. Photoelectron data for adsorption of ghosts indicate that both proteins and phospholipids must be adsorbed onto chrysotile fibres.

Asbestos↗

PubMed1980

Biological effects of attapulgite.

Some clay minerals occur naturally in a fibrous or lath-like crystal state as attapulgite and sepiolite. Because of their sorptive and colloidal properties, attapulgite and sepiolite have numerous industrial applications, mainly as additives in oil-drilling muds, in chemical fertilizers, pesticides, paints, adhesive products, bleaching agents, cosmetic compounds and phytosanitary products. World consumption of each is over one million tons annually. Acid-treated attapulgite is used in the composition of certain drugs used for the treatment of gastrointestinal diseases. Such drugs available commercially in France were analysed for their mineral content by transmission electron microscopy and found to contain attapulgite fibres [mean length: 0.9 micrometers (0.1-3.6); mean diameter: 0.05 micrometers (0.01-0.5)]. The haemolytic activities of a Spanish attapulgite sample and of three samples of drugs sold in France were greater or similar to that of UICC chrysotile asbestos. Attapulgite fibres were encountered in large quantities in the lung washing fluid of a patient suffering from lung fibrosis who had been exposed recently for three years during the processing of attapulgite material. Attapulgite fibres were also found in a urine sample from a patient who had ingested 6-9 g/day of an attapulgite drug for six months.

Adult↗

PubMed1980

How pleural mesothelial cells react in vitro with chrysotile fibres.

A culture system of rat pleural mesothelial cells has been developed for short-term experiments and long-term maintenance. In short-term experiments, endocytosis of chrysotile fibres (100 microgram/ml) has been demonstrated by electron microscopy of the pleura in situ. Structural modifications, mainly cytoplasmic vacuolization, were observed when the cells were cultured with sublethal doses of chrysotile (0.5, 1, 2 and 10 micrograms/ml). Untreated cells had a mean population doubling time of 37 hours. When the cells were treated with 2 or 10 micrograms/ml, the mean population doubling time was slightly increased.

Animals↗

PubMed1979

[Adsorption of phospholipids by chrysotile fibers : comparison of data from chemical analysis and photoelectron spectrometry (PSX method)].

The adsorption of dipalmitoyl phosphatidyl choline (DPPC) by chrysotile fibers was carried out by chemical and photoelectron spectroscopy analysis. The adsorption isotherms have shown that maximum adsorption was about 130 microgram of DPPC per milligram of chrysotile. The results are in good agreement with estimates of a bilayer adsorption.

Adsorption↗

PubMed1979

Inhibition by phospholipids of haemolytic action of asbestos.

Haemolysis by asbestos fibres results from an increase in membrane permeability and not from rupture of red blood cells (RBC). The effect of chrysotile asbestos on RBC is at least partly, if not completely, attributable to lipid extraction and adsorption on to the fibres. This was suggested by the hyperbolic relationship between the haemolytic activity of chrysotile and the relative concentration of both chrysotile and RBC. Moreover, it was shown that pre-incubation of chrysotile with lipids, either as RBC membranes or with pure lipids in the form of liposomes, prevents haemolysis.

Asbestos↗

PubMed1979

[Fibre interaction with red blood cells or alveolar macrophages "in vitro" (author's transl)].

Haemolytic activities and effects on alveolar macrophages (AM) of various fibres were studied. UICC asbestos fibres and attapulgites either untreated or acid-leached were used. Amphiboles and commercial attapulgites were both cytotoxic on AM, but attapulgites and chrysotile were only haemolytic. Chrysotile fibres induced a release of B galactosidase; when acid treated these fibres were cytotoxic and less haemolytic. Acid treated amphiboles were more haemolytic than untreated.

Asbestos↗

PubMed1979

Phagocytosis of chrysotile fibers by pleural mesothelial cells in culture.

Pleural mesothelial cells (PMC) from the parietal pleura of rats were incubated in culture with UICC A chrysotile fibers. The sequence of events in phagocytosis was studied by electron microscopy: phases of attachment sequestration, and degranulation of lysosomal content into the phagocytic vacuole were observed. This demonstrates that PMC can engage in phagocytosis of chrysotile fibers.

Animals↗

PubMed1978

Partial characterisation of an elastase-like enzyme secreted by human and monkey alveolar macrophages.

An elastinolytic activity on soluble and insoluble elastin has been demonstrated in the culture medium of human and monkey alveolar macrophages. This activity is potentiated by latex particles in the medium. An enzyme resembling some other elastases was partially purified and characterised. It differs from other elastases in its affinity for elastin and a synthetic substrate, its susceptibility to various kinds of inhibitors and by its metal ion requirement.

Animals↗

PubMed1978

Biological effects of chrysotile after SO2 sorption. II. Effects on alveolar macrophages and red blood cells.

An experimental study has been carried out using different biological and biochemical in vivo and in vitro tests for assessing the toxicity of natural UICC (A) chrysotile and SO2-sorbed UICC (A) chrysotile and for detecting a possible synergistic effect. For in vivo studies, rabbits received an intratracheal injection of chrysotile fibers suspended in physiological saline (PS). The control group received only PS; all animals were sacrificed after 68 hr. The alveolar free cells were harvested by pulmonary lavage. The results have shown that chrysotile induces a decrease in the free cell population but there was no significant difference in the number of viable cells or in the nature of cells harvested between the two chrysotile groups. Enzymatic activities of the alveolar macrophages from animals injected with SO2-sorbed chrysotile showed a significant increase of the enzymes LDH and acid phosphatases. The LDH increase could be related to the affinity of the enzyme regarding some chemical forms of SO2. In vitro studies using alveolar macrophages harvested by pulmonary lavage have shown no differences between the two chrysotile groups when cell viability and enzyme release were studied. The toxic effect was due to chrysotile fibers (decrease of 38% in cell viability and increase in cellular enzyme release when compared with control). When rabbit red blood cells were used, both natural and SO2 chrysotile fibers showed the same hemolytic activity. The failure to detect high differences between the two chrysotile groups may be related to the chemical form of sorbed SO2.

Acetylglucosaminidase↗

PubMed1978

Biological effects of chrysolite after SO2 sorption. iii. effects on the biochemical components of alveolar washing.

The short-term effects of chrysotile asbestos before and after SO2 sorption are studied in the rabbit after intratracheal injection of low doses of these pollutants. Chrysotile, as well as SO2-chrysotile, induces an increase in the unsaturated fatty acid content of lung surfactant, which is similar to that observed in the respiratory distress syndrome of the newborn, and an increase in the protein level of pulmonary washings which may be explained by an increase of the permeability of the blood-air barrier. These soluble proteins can interact with the surfacant and thus decrease its tensio-active properites.

Animals↗