Opinion ID: 326929
Heading Depth: 4
Heading Rank: 2

Heading: Animal Studies and Penetration of the Gastrointestinal Mucosa.

Text: 99 At a somewhat more theoretical level, the determination of whether ingested fibers can penetrate the gastrointestinal mucosa bears on the issue of harm through ingestion. If penetration is biologically impossible, then presumably the interaction of the fibers with body tissues will not occur. 100 This medical issue has been investigated through experiments with animals which, unfortunately, have produced conflicting results. For example, Reserve witness Dr. Davis reported on his experiment in feeding crocidolite and chrysotile asbestos to rats for varying periods of up to six months. He killed the rats at the end of the period and examined their gastrointestinal tissues for evidence of fibers. At the time of trial, light and electron microscopy had so far revealed no evidence of fibers in the tissues. (A.16:143-59.) 101 Plaintiffs, however, cited contrary studies. Research by George Westlake, in which rats were fed a diet including chrysotile fibers, indicated that fibers had traveled through the colon wall and accumulated in the area of the mesothelium. 44 (A.11:23-25.) Pontrefact, who injected chrysotile fibers into the stomachs of rats, found that fibers had dispersed throughout the body tissues. 45 (A.11:37-41.)On this conflicting scientific evidence, Dr. Brown testified that the Westlake and Pontrefact studies provide some support for the hypothesis that asbestos fibers can penetrate the gastrointestinal mucosa. 46 102