PubMed Health⌕ Search

Biomedical subjects

L Magne

Publications and source records attributed to L Magne.

16 recordsLinked to original sources
PubMed1988

Quantitation of elastin in human urine and rat pleural mesothelial cell matrix by a sensitive avidin-biotin ELISA for desmosine.

A specific enzyme-linked immunosorbent assay (ELISA) was developed for the determination of desmosine, a cross-linked amino acid specific to fibrous elastin. Competition between solid phase-bound desmosine-protein conjugate and free desmosine for binding to monospecific anti-desmosine antiserum constituted the underlying principle of the assay. The conjugation of desmosine to different protein carriers was carried out with the 1-ethyl-3-(dimethylamino-propyl)carbodiimide (ECDI); rabbits were immunized with desmosine-bovine serum albumin and micro-titer plates were coated with desmosine-egg albumin. An avidin-biotin peroxidase system was used to reveal anti-desmosine antibodies bound to the desmosine-protein conjugate. As both conjugates revealed new non-specific common epitopes on the carrier proteins, prior absorption of the anti-desmosine antiserum on rabbit albumin polymerized with ECDI was required to remove the antibodies directed against these neo-antigens. The absorption procedure resulted in an increased specificity and sensitivity. Values ranging from 0.07 to 4 ng of desmosine/well could be detected and this sensitivity was greater than that obtained in previous immunoassays for desmosine. In order to assess the specificity of the test, samples containing aminoacids and urine hydrolysates were included in an assay. Some cross-reactivity was observed with the desmosine precursor lysinonorleucine and the desmosine isomer isodesmosine but, in contrast the very low cross-reactivity observed with collagen hydrolysate was similar to that exhibited by albumin hydrolysate. Analysis of urine samples from 118 normal male volunteers showed, firstly, that urinary creatinine measurement was a good indicator of the amount of urine which could be safely introduced in the assay without risk of non-specific interference by other organic compounds and, secondly, that the desmosine/creatinine ratio was a reliable index for an in vivo assessment of degraded elastin excretion. The assay also allowed quantitation of elastin fiber biosynthesis in the connective tissue matrix of cultured rat pleural mesothelial cells. This ELISA for demosine is a simple technique which should be useful for further in vivo or in vitro investigations of fibrous elastin tissue metabolism.

Amino Acids↗
PubMed1987

The interactions between asbestos fibers and metaphase chromosomes of rat pleural mesothelial cells in culture. A scanning and transmission electron microscopic study.

Rat pleural mesothelial cells (PMCs) in culture at the exponential growing phase were exposed to 5 micrograms/ml of chrysotile (CH) or crocidolite (CR) asbestos fibers: the cells and their chromosomes were studied 48 hours thereafter by light, scanning, and transmission electron microscopy (LM, SEM, TEM). PMCs phagocytized both CH and CR. Mild vacuolar cytoplasmic changes by LM and a few small surface blebbings by SEM were present, mainly in cells treated with CH. Metaphase chromosomes were well separated and retained surface details by SEM in the control group. Chromosomes were frequently entangled with, adherent to, and severed or pierced by long and thin curvilinear CH with occasional chromatin fibers threading over the partly severed asbestos. Similar chromosomal changes were much less frequently found in CR-treated cells; TEM confirmed the same findings. CH and CR have different physicochemical properties and also appear to have direct, intricate, but different interactions with chromosomes, as well as the cytoplasm, of PMCs.

Animals↗
PubMed1986

Chromosomal changes induced by chrysotile fibres or benzo-3,4-pyrene in rat pleural mesothelial cells.

The induction of chromosomal aberrations in rat pleural mesothelial cells (RPMC) following in vitro treatment with chrysotile fibres has been demonstrated. The production of chromosomal aberrations was also observed after treatment of the cells with benzo-3,4-pyrene (BP). The yield of abnormal metaphases was dose-dependent and reached 58% at a BP dose of 2 micrograms/ml. Chrysotile fibres at 7 micrograms/ml induced 21% abnormal metaphases and the frequency decreased with further increases in fibre concentration. Their decline is possibly related to a lethal effect. Chrysotile-induced chromosomal aberrations were primarily of the chromatid type and included breaks and fragments. BP induced chromosome exchanges which were not seen following chrysotile treatment. Minutes and double minutes were detected in BP-treated RPMC and occasionally found after chrysotile application. These results confirm that chrysotile fibres are clastogenic for some cultured cells and demonstrate that the fibres induce chromosome damage in target RPMC.

Animals↗
PubMed1986

In vitro growth characteristics of rat mesothelioma cells in culture.

The study reports morphological growth characteristics and chromosome analysis of neoplastic rat pleural mesothelial cells (RPMC) isolated from a mesothelioma-bearing rat. The pleural mesothelioma was induced by intrapleural injection of chrysotile fibers. Neoplastic RPMC were cultured by the standard methods used for normal RPMC. Neoplastic RPMC cultures had a population doubling time of 19 hr versus 30 hr for the normal cells. Plating efficiency in liquid medium was almost 100%. Cultures of neoplastic RPMC were anchorage-independent since 70% of the seeded cells formed colonies after one week; after the second week, colony size was enhanced but colony recovery was not. The serum dependence of neoplastic cells was less than that of the normal cells. 79 out of 100 metaphase cells analyzed had 41 to 43 chromosomes, and the modal number was 42 (38%). A large metacentric chromosome was observed in 77 of the 100 neoplastic metaphase cells analyzed, but not in any normal metaphase cells. In nude mice, the neoplastic RPMC were tumorigenic.

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

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↗
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↗
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

[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↗
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↗
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↗