Structural changes of the gastrointestinal mucosa induced by prostaglandins

Bis-(2-Chloroisopropyl) ether

Bis-(2-Chloroisopropyl) ether (BCIPE) was used as a solvent for fats, greases, paint, varnish removers, and in spotting and cleaning solutions. However, BCIPE has not been commercially manufactured or used for numerous years. In experimental animal studies, BCIPE is moderately toxic following acute oral, dermal, and inhalation routes of exposure. BCIPE is a severe eye irritant but not a dermal irritant or dermal sensitizer. BCIPE was not genotoxic or mutagenic in in vitro and in vivo assays; it was not toxic in a 3-generation reproductive dietary study in rats. Short-term, repeated inhalation and oral exposure in rats produced increased liver and kidney weights and congestion; dermal exposure in rabbits did not produce any observable adverse effects. BCIPE did not produce a statistically significant increase in tumors in two different 2-year dietary studies in mice and rats. In mice, technical grade BCIPE produced increased incidences of alveolar/bronchiolar adenomas in females, hepatocellular carcinomas in males, and a low incidence of forestomach hyperplasia (in both sexes at the high-dose). Further investigation with technical grade BCIPE concluded that these effects were species- and dose-specific with limited, if any, relevance to humans. The NOAEL of 400 ppm (15 mg/kg/day) from the 2-year dietary study in female rats was considered the point of departure for the health-based WEEL derivation. After adjustment for duration of exposure, interindividual variability, and intraindividual variability, an 8-h time-weighted average (TWA) WEEL value of 3 ppm (21 mg/m3) was derived. This exposure limit is expected to provide a significant margin of safety against any potential adverse health effects in workers.

Digestive System 1

This chapter deals with the digestive system. The major and minor salivary glands and their secretions also represent and integral part of the protective mechanism of the oral cavity, and derangement of saliva production may lead to loss of integrity of the oral mucosa. Drug-induced abnormalities of taste sensation are also well-described phenomena occurring in man although human studies are necessary for the detection of these effects. Inflammation of the oral cavity may involve the buccal mucosa, the gingiva (gingivitis), the tongue (glossitis), and the peridontal tissues (peridontitis). Therapeutic agents can induce inflammatory lesions in the tongue. Moreover, a protective layer of mucus, a visco-elastic material containing high molecular weight glycoproteins produced by the major and minor salivary glands, covers the stratified squamous mucosa of the oral cavity. Salivary secretions also possess digestive enzyme activity although in herbivores and carnivores, it is usually low in contrast to high digestive enzyme activity in omnivorous species.

Gross and histologic effects of topical misoprostol on canine gastric mucosa

This study reports the histological effects of topical misoprostol, a synthetic PGE1 analog, administered in varying dosages on the resting canine gastric mucosa. Misoprostol did not macroscopically or microscopically damage the mucosa but its presumed permeability effects on the gastric vasculature induced marked edema of the mucosa and submucosa. Consistent features included increased thickness of both layers, dilated interglandular regions of the lamina propria, marked subepithelial edema, reduced depth and width of gastric foveolae, vasodilation of the vascular channels, reduced height of surface epithelial cells, swelling of their basolateral intercellular spaces, and increased amounts of surface adherent mucus. It is speculated that the mucosal edema, in addition to an increased mucus layer, may be important in the mechanism of gastric cytoprotection by increasing the distance of penetration or absorption for a mucosal-damaging agent, diluting its concentration, and disseminating any focal accumulations of red blood cells.