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Absence of genotoxic effects of nonasbestos mineral fibers (1985)

Denizeau, Francine ; Marion, Michel ; Chevalier, Gaston ; [et al.]

Springer

Cell biology and toxicology 1 (1985), S. 23-32

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ISSN: 1573-6822

Keywords: genotoxicity ; UDS ; hepatocytes ; attapulgite ; xonotlite ; sepiolite

Source: Springer Online Journal Archives 1860-2000

Topics: Biology , Medicine

Notes: Abstract The biological activity of natural and synthetic mineral fibers has been examined. Natural attapulgite [(Mg, Al)2Si4O10(OH).4H20], synthetic xonotlite [Ca3Si3O8(OH)2] and natural sepiolite [Mg2Si3O8.2H2O] were selected. Genotoxic effects were investigated by means of a well established cellular model based upon the measurement of unscheduled DNA synthesis (UDS) in rat hepatocytes in primary culture. The intrinsic capacity of the fibers (1 and 10 µ/ml) to induce UDS was first tested. None of the fiber types showed detectable UDS-eliciting activity. Also, the possible modulation of the cellular response to genotoxic agents by the materials was examined by exposing the cells to mixtures of 2-acetylaminofluorene (AAF) (0.05 and 0.25 µg/ml) and fibers (1 and 10 µg/ml). In these experiments, the UDS response was significantly diminished in the presence of xonotlite. This phenomenon may reflect changes in the uptake and/or metabolism of AAF or may result from an inhibition of DNA repair processes, the latter suggesting a possible cocarcinogenic potential for this synthetic silicate. These results point to the immediate necessity of studying more extensively the biological effects of fibrous materials that can be used as substitutes for asbestos.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF00717788

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In Vivo incorporation of choline-3H, leucine-3H and galactose-3H in alveolar type II pneumocytes in relation to surfactant synthesis. A quantitative radioautographic study in mouse by electron microscopySupported by grant, MA, 3086, from the Medical Research Council of Canada. The authors wish to thank Mrs. Gabrielle Guay for her technical assistance. (1972)

Chevalier, Gaston ; Collet, Andre J.

New York, NY [u.a.] : Wiley-Blackwell

The @Anatomical Record 174 (1972), S. 289-310

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ISSN: 0003-276X

Keywords: Life and Medical Sciences ; Cell & Developmental Biology

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Medicine

Notes: A quantitative time study of the incorporation of choline-3H, leucine-3H and galactose-3H in lung epithelial cells, was undertaken in vivo with electron microscopic autoradiography. Type II pneumocytes were selectively labeled with choline-3H, a specific precursor of phosphatidylcholine, which is the main component of pulmonary surfactant. Choline was initially localized in endoplasmic reticulum, then was rapidly transferred through the Golgi complex and stored in lamellar bodies. Previously undescribed small lamellar bodies are suggested as phospholipid carriers between Golgi complex and lamellar bodies. After initial incorporation in the endoplasmic reticulum, the leucine label migrated through the Golgi complex into lamellar bodies by fusion of multivesicular bodies, which are the carriers between the two structures. Galactose was modestly incorporated into lamellar bodies via the Golgi complex. Intra-alveolar myelin figures, recognized as excreted surfactant, were labeled 120 minutes after injection with the three precursors.These findings indicate that the synthesis of a secretory product by type II pneumocytes involves phospholipid, protein and polysaccharide precursors; the secretory product is segregated as lamellar bodies which are destined to be excreted into the alveolar cavity to become part of the lining layer.

Additional Material: 19 Ill.