TY - JOUR
T1 - Free radical activity of syntheticvitreous fibers
T2 - Iron chelation inhibits hydroxyl radical generation by refractory ceramic fiber
AU - Brown, David M.
AU - Fisher, Carolyn
AU - Donaldson, Ken
N1 - Funding Information:
Received 26 May 1997; sent for revision 30 June 1997; accepted 19 August 1997. This research was funded by the Health and Safety Executive. We also acknowledge an equipment grant from the British Occupational Health Research Foundation. K. Donaldson holds the British Lung Foundation/BitishrGas Transco Fellowship in Air Pollution and Respiratory Health. Address correspondence to Professor Ken Donaldson, Biomedicine Research Group, Department of Biological Sciences, Napier University, Edinburgh EH10 5DT, Scotland. E-mail: k.donaldson@ napier.ac.uk
PY - 1998/4
Y1 - 1998/4
N2 - Synthetic vitreous fibers are in widespread use but the parameters that dictate their carcinogenicity are still a matter of scientific debate. The free radical activities of a panel comprising an asbestos sample and five different respirable synthetic vitreous fiber samples were determined, to address the hypothesis that carcinogenic fibers have greater free radical activity than noncarcinogenic fibers. On the basis of recentinhalation studies, the six samples were divided into three carcinogenic fibers-amphibole asbestos, silicon carbide, and refractory ceramic fiber 1 (designated with the abbreviation RCF 1)-and three noncarcinogenic fibers-man-made vitreous fiber 10 (a glass fiber sample designated with the abbreviation MMVF 10), Code 100/475 glass fiber, and RCF4. All experimentswere carried out with equal fiber numbers. Of the two assays of free radical activity used, the plasmid assay of DNA scission showed only amosite asbestos to have free radical activity, while the salicylate assay of hydroxyl activity showed that both amosite asbestos and RCF1 release hydroxyl radicals; silicon carbide fibers had no free radical activity in eitherof the assays. None of the noncarcinogenic fibers demonstrated free radical activity in either of the assays. The differences in the two assays indemonstrating free radical activity with RCF1 may be due to increased release of Fe from RCF1 under the more acid conditions of the salicylate assay, which was confirmed by the fact that soluble iron caused hydroxylation of salicylate. Presence of an iron chelator inhibited the ability of the RCF1 fibers to cause hydroxylation of salicylate, demonstrating that RCF1 generates hydroxyl radical by Fenton chemical reaction in the same wayas amphibole asbestos.
AB - Synthetic vitreous fibers are in widespread use but the parameters that dictate their carcinogenicity are still a matter of scientific debate. The free radical activities of a panel comprising an asbestos sample and five different respirable synthetic vitreous fiber samples were determined, to address the hypothesis that carcinogenic fibers have greater free radical activity than noncarcinogenic fibers. On the basis of recentinhalation studies, the six samples were divided into three carcinogenic fibers-amphibole asbestos, silicon carbide, and refractory ceramic fiber 1 (designated with the abbreviation RCF 1)-and three noncarcinogenic fibers-man-made vitreous fiber 10 (a glass fiber sample designated with the abbreviation MMVF 10), Code 100/475 glass fiber, and RCF4. All experimentswere carried out with equal fiber numbers. Of the two assays of free radical activity used, the plasmid assay of DNA scission showed only amosite asbestos to have free radical activity, while the salicylate assay of hydroxyl activity showed that both amosite asbestos and RCF1 release hydroxyl radicals; silicon carbide fibers had no free radical activity in eitherof the assays. None of the noncarcinogenic fibers demonstrated free radical activity in either of the assays. The differences in the two assays indemonstrating free radical activity with RCF1 may be due to increased release of Fe from RCF1 under the more acid conditions of the salicylate assay, which was confirmed by the fact that soluble iron caused hydroxylation of salicylate. Presence of an iron chelator inhibited the ability of the RCF1 fibers to cause hydroxylation of salicylate, demonstrating that RCF1 generates hydroxyl radical by Fenton chemical reaction in the same wayas amphibole asbestos.
UR - http://www.scopus.com/inward/record.url?scp=0032502657&partnerID=8YFLogxK
U2 - 10.1080/009841098159132
DO - 10.1080/009841098159132
M3 - Article
C2 - 9561968
AN - SCOPUS:0032502657
SN - 1528-7394
VL - 53
SP - 545
EP - 561
JO - Journal of Toxicology and Environmental Health - Part A
JF - Journal of Toxicology and Environmental Health - Part A
IS - 7
ER -