Linked Life Data

12641433

Source:http://linkedlifedata.com/resource/pubmed/id/12641433

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
2003-3-18
pubmed:abstractText
Ascorbic acid is one of the major components of the antioxidants defenses of the lung lining layer where inhaled asbestos fibers are deposited. Crocidolite fibers were incubated at 37 degrees C in a 0.01 M aqueous solution of ascorbic acid for 25 days in order to investigate modifications in surface reactivity. Iron (820 nmol/mg) and monomeric silica (470 nmol/mg) were released in the supernatant, while ascorbic acid was consumed. The amount of iron and silicon released, respectively, 17 and 6% (in atoms) of the total fiber content, exceeded what was expected at the surface, suggesting a partial disgregation of crocidolite promoted by ascorbic acid. In the absence of ascorbic acid but at the same pH, the release of iron and monomeric silica was minimal. At time intervals, aliquots of fibers were withdrawn to evidence chemical modifications progressively taking place. Three families of Fe(II) centers, differing in coordinative unsaturation and progressively removed during incubation, have been evidenced from the FTIR spectra of NO adsorbed onto the fibers. The most uncoordinated ones are removed first. New highly uncoordinated iron sites are exposed at the fiber surface as a consequence of the erosion of the outmost layers while hydration of silica tetrahedra yields new silanol groups. The activity in the Fenton-like reaction (*OH from H(2)O(2)) decreases following surface iron depauperation. Conversely, the homolytic cleavage of the C-H bond (CO(2)*-) from the formate ion) appears related to the small fraction of iron ions always present but easily quenched by the adsorption of ascorbic acid or its oxidation products.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Mar
pubmed:issn
0893-228X
pubmed:author
pubmed:issnType
Print
pubmed:volume
16
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
328-35
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
2003
pubmed:articleTitle
Ascorbic acid modifies the surface of asbestos: possible implications in the molecular mechanisms of toxicity.
pubmed:affiliation
Dipartimento di Chimica IFM and Interdepartmental Center G Scansetti for Studies on Asbestos and other Toxic Particulates, Università degli Studi di Torino, Via P Giuria 7, I-10125 Torino, Italy.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't