Concentrations and dimensions of coated and uncoated asbestos fibres in the human lung.

Abstract

Concentrations and length distributions of uncoated and coated amphibole-type fibres in samples of human lung taken at necropsy were measured by optical microscopy using the membrane filter technique that enables fibres with diameters down to about 0-2 ,um to be detected. The subjects included 10 who died with mesothelial tumours, three with lung cancer, and eight of other causes. Measurements of fibre concentrations are compared with those of other workers. It can be deduced from the length distributions that fibres less than 5 ,um long are cleared from the lung more efficiently than longer ones. The clearance of short fibres appears to be inhibited in subjects with asbestosis, however. The length distributions of uncoated and coated fibres were dissimilar. In general, few fibres < 10 ,um in length were coated and few > 40 ,tm in length were uncoated.

Analysis of inorganic fiber concentrations in biological samples by scanning electron microscopy.

“…The use of sonication for the homogenization of fi;ber suspensions has also been discussed 'by Morgan & Holmes (6). There are two mai'n features, a homogeneous dispersion ,and a rapid dissolution of the tissue salits.…”

“…As pointed out by Ascroft & HeppleS'ton (1) and Morg,an & Holmes (6), fiber losses or even an iJncrease in fiber nurrib'€r may oocur during the digestion {WD) of tissue sample for quanti,ta'tive fiber estimation. Errors may also ,be iJntroduced by LTA (6).…”

Dynamics of the Lung Function in Asbestos Pleural Disease

“…Particles that have not been cleared from the respiratory system or completely phagocyted cause permanent irritation that can lead to changes in the lung parenchyma or pleura (3)(4)(5)(6). Morgan and Holmes have proved that the critical length of asbestos fibre is 17 µm (6).…”

Topographic and size distribution of asbestos bodies in exposed human lungs

“…Recent data published by Morgan & Holmes (10) give the ratio, based on light microscopic analysis, between coated and uncoated fibers in human lung tissue. Such data are biased as long as only a small part of the uncoated fibers in lung tissue samples can be detected by optical microscopy.…”

“…It has clearly been established that fibers shorter than 10 lim very rarely form asbestos bodies (10,11). In human lung the detoxifying mechanisms leading to the formation of coated fibers also act on nonasbestos fibers (5).…”