Appearance of very electrophilic species generated by some iron oxides: effect of iron chelators and reducing agents
It is now well known that asbestos fibers are responsible of several lung diseases. This toxicity is suggested to be due to the presence of Fe(II) in the structure of the fibers, or in their contaminants (Zalma et al 1987). Moreover, an excess incidence of lung cancer has been found among workers in various metal mines (Mur et al 1987), in iron and steel foundries (IARC monographs 1984) and also among arc welding workers (IARC monographs 1990) pointing to possible carcinogenic properties of iron-containing mineral dusts. In the case of Fe(II) compounds, this toxicity is due to the activation of dioxygen in biological medium by divalent iron appearing at the interface solid-liquid or in solution, which may lead to the formation of various activated oxygen species (AOS). In the set of these AOS, the very electrophilic species are symbolized by A* (Pezerat 1991); they include ferryl, perferryl and OH. (Yamazaki et al 1990 and Bielski et al 1992). The quantitation of the oxidizing power of the A* species is obtained through a reaction of H abstraction between A* and a target molecule, the formate anion (Zalma et al 1987). The production of the C0 2 - · is measured using a spin-trap agent, the DMPO (5-5’-dimethyl-1-pyrroline-N-oxide), giving an adduct (DMPO, CO 2 - whose life time allows its identification by ESR spectroscopy.
KeywordsIron Chelator Activate Oxygen Species Sodium Formate Asbestos Fiber Divalent Iron
Unable to display preview. Download preview PDF.
- Allen, G.C., Tucker, P.M. and Wild, P.K. (1982) Characterization of iron/oxygen surface reactions by X-ray photoelectron spectroscopy. Philos. Mag. B. 46: 411Google Scholar
- Bielski, B.H.J. (1992) Reactivity of hypervalent iron with biological compounds. Ann. Neurol. 32: 28–32Google Scholar
- Fournier, J., Guignard, J., Nejjari, A., Zalma, R. and Pezerat, H. (1991) The role of iron in the redox surface activity of fibers. Relation to carcinogenicity. In “Mechanisms in Fiber Carcinogenesis” ( Brown R.C. ed.) Plenum Press, New York: 407–414Google Scholar
- IARC Monographs (1984): On the evolution of carcinogenic risk to humans: Polynuclear aromatic compounds, part 3: Industrial exposures in aluminium production, coal gasification, coke production, and iron and steel founding. Lyon. France. 34: 133–190Google Scholar
- IARC Monographs (1990): On the evolution of carcinogenic risk to humans: Chromium, nickel and welding. Lyon. France. 49: 447–526Google Scholar
- Jolivet, J.P., Tronc, E., Barbe, C. and Livage, J. (1990) Interfacial electron transfer in colloidal spinel iron oxide: Silver ion reduction in aqueous medium. J. Colloid. Interface. Sc. 138:2:465–472 Mur, J.M., Meyer-Bisch, C., Pham, Q.T.,Massin, N., Moulin, J.J., Cavelier, C. and Sadoul, P. (1987) Risk of lung cancer among iron ore miners. J. Occupat. Med. 29: 9762–768Google Scholar
- Pezerat, H. (1991) The surface activity of mineral dusts and the process of oxidative stress. In “Mechanisms in Fiber Carcinogenesis”. ( Brown R.C. ed.) Plenum Press, New York. 387–395Google Scholar