Carcinogenicity of Fibrous Glass: Pleural Response in the Rat in Relation to Fiber Dimension

Abstract

Seventeen fibrous glasses of diverse type or dimensional distribution induced different incidences of malignant mesenchymal neoplasms when implanted in the pleurae of female Osborne-Mendel rats for periods of more than 1 year. Neoplastic response correlated well with the dimensional distribution of fibers. Fibers less than or equal to 1.5 mu in diameter and greater than 8 mu in length yielded the highest probability of pleural sarcomas, and probability trends suggested that pleural sarcoma incidence increased with increasing lengths of fibers with diameters of less than 1.5 mu, Morphologic observations indicated that fibers less than or equal to 8 mu in length were inactivated by phagocytosis. In fibers greater than 8 mu in length, the correlation of carcinogenicity witth increasing length was difficult to explain. Since neoplastic response to a variety of types of durable fibers, particularly asbestos fibers, was similar, our experiments reinforce the idea that the carcinogenicity of fibers depends on dimension and durability rather than physicochemical properties and emphasize that all respirable fibers be viewed with caution.

Possible Application of Urinary Analysis to Estimate Dissolution of Some Man-Made Vitreous Fibers

“…Certain fibers eventually are eliminated via bronchial or lymphatic action, though the time this takes may vary. Other fibers remain in the pulmonary fluids, undergoing transformation including fragmentation and partial dissolution (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12). The chemical elements liberated by dissolution of fibers in the lungs can therefore spread throughout the organism before being eliminated (13,14), for example by urinary or biliary action.…”

On the Calculation of Aerodynamic Diameters of Fibers

“…There is a considerable interest in the prediction of the aerodynamic behavior of elongated particles, particularly in view of the quantitative observations that long mineral fibers can penetrate deep into the human respiratory tract (Timbrell, 1982) where they can cause size-and shape-dependent severe toxicological effects (Stanton et al, 1981). Harris and Fraser (1976) proposed a mathematical model for deposition of fibers in human airways, based on the theoretical aerodynamic behavior of thm straight rods.…”

La recherche sur le cancer

“…En effet, certains corps étrangers chimiquement inertes (cellulose, verre), implantés chez l'animal, peuvent induire des sarcomes [7]. En outre, un même corps étranger, selon sa structure et sa taille (diamètre des pores, longueur des fibres) pourra induire ou non un cancer [8,9]. D'autres travaux ont montré qu'une lignée cellulaire dérivée d'un polype adé-nomateux humain est non tumorigénique lorsqu'elle est implantée sous la peau chez des souris nude, alors qu'elle devient tumorigé-nique lorsqu'elle est implantée avec une plaque de plastique qui induit une forte inflammation [10].…”