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Do vitreous fibers break in the lung?

Authors
Eastes-W; Baron-PA; Baier-RE; Guldberg-M; Potter-R
Source
Inhal Toxicol 2007 Jan; 19(4):311-315
NIOSHTIC No.
20031782
Abstract
In order to determine whether breakage of long vitreous fibers in the lung could be responsible for removing significant numbers of these fibers, an intratracheal instillation study was done with a preparation consisting of mostly long fibers of two different types. Following instillation of both fibers, laboratory rats were sacrificed at 6 times up to 14 days. The NK (conventional borosilicate glass) fiber preparation had about 20% short fibers (length <= 15 mu m) initially, and fibers recovered from the lungs remained at that proportion for the entire 14 days. But the HT (a new rock or stone wool) fiber preparation, which had about 5% short fibers initially, jumped to about 50% short fibers at 2 days and remained at that proportion for the rest of the study. The appearance of many short HT fibers where there were few initially is conclusive evidence that these long fibers break, and it explains their rapid removal from the lung. Since the HT fibers dissolve rapidly at acid pH, but slowly at the near neutral pH of the extracellular lung fluid, it is likely that acid attack by phagocytic cells is causing the long fibers to dissolve and break. The long NK fibers dissolve rapidly at neutral pH but slowly at acid pH and thus appear to clear by more or less uniform dissolution without apparent breakage. The long fibers of these two kinds are removed rapidly at about the same rate, but by a different mechanism.
Keywords
Laboratory-animals; Animal-studies; Biodynamics; Pneumography; Lung-fibrosis; Lung-tissue; Fiber-deposition; Inhalation-studies; Pulmonary-congestion; Pulmonary-disorders; Pulmonary-system-disorders
Contact
W Eastes, 288 Bryn Du Dr, Granville, OH 43023
CODEN
INHTE5
Publication Date
20070101
Document Type
Journal Article
Email Address
eastes@infinet.com
Fiscal Year
2007
NTIS Accession No.
NTIS Price
Issue of Publication
4
ISSN
0895-8378
NIOSH Division
DART
Priority Area
Manufacturing
Source Name
Inhalation Toxicology
State
OH; NY
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