Gastrointestinal Tract Tumors

Lebedeva, G. A. (1963). Gastrointestinal tract tumors induced by radiocerium (Ce144), Fed. Proc. Transl. Suppl. 23, T526 (Translated from Arkh. Patol. 25, 40). 

Daniel FB, DeAngelo AB, Stober JA, et al. 1989. Chloroform inhibition of 1,2-dimethylhydrazine-indueed gastrointestinal tract tumors in the Fisher 344 rat. Fundam Appl Toxieol 13 40-45. 

Swallowing. If it is sufficiently irritant or caustic, a swallowed material may cause local effects on the mouth, pharynx, esophagus, and stomach. Additionally, carcinogenic materials may induce tumor formation in the alimentary tract. Also, the gastrointestinal tract is an important route by which toxic materials are absorbed. The sites of absorption and factors regulating absorption have been reviewed (42,43). 

Yamashita reported anti-inflammatory effect of astaxanthin when administered with aspirin. An oral preparation has been developed by Alejung and Wadstroem for the treatment of Helicobacter infections of the mammalian gastrointestinal tract. Strong evidence suggested that astaxanthin modulated the humoral and non-humoral immune systems. It enhanced the release of interleukin-1 and tumor necrosis factor-... 

Gastrointestinal Effects. Though tumors of the small intestine were noted in a comprehensive and well-conducted study by Quast et al. (1980a) (see Section 2.2.1.8), there were no nonneoplastic histopathologic changes observed in any portion of the gastrointestinal tract of rats at doses up to 80 ppm for 2 years. 

Hormones transfer signals by migrating from their site of synthesis to their site of action. They are usually transported in the blood. In this case, they are said to have an endocrine effect (1 example insulin). By contrast, tissue hormones, the target cells for which are in the immediate vicinity of the glandular cells that produce them, are said to have a paracrine effect (2 example gastrointestinal tract hormones). When signal substances also pass effects back to the cells that synthesize them, they are said to have an autocrine effect (3 example prostaglandins). Autocrine effects are often found in tumor cells (see p. 400), which stimulate their own proliferation in this way. 

There is limited evidence of carcinogenicity in experimental animals. However, in one report arsenic administered for 2 years in the drinking water of female mice was associated with an increased incidence in tumors involving lung, liver, gastrointestinal tract, and skin. ... 

C. Carcinoid tumors arise from neuroendocrine cells of the gut and secrete serotonin and gastrointestinal hormones, which activate the gastrointestinal tract and result in diarrhea. Most of these tumors have receptors for somatostatin, which inhibit secretion when activated, resulting in reduced activity of the gut. Octreotide is a stable analogue of... 

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