Assessing stomach

Tsugani S, Tsuda M, Gey F and Watanabe S. 1992. Cross-sectional study with multiple measurements of biological markers for assessing stomach cancer risks at the population level. Environ Health Perspect 98 207-210. 

Solubility and dissolution are processes that take place in the gastric and the luminal fluids, not on the surface of epithelial cells. Measurement of solubility ideally needs to take place at pH 1.7 (stomach) and pH 5-8 (small intestinal tract). Ideally, the screen media should resemble intestinal fluids and contain bile acid-lecithin mixed micelles. Fast and reliable techniques for assessing solubility in... 

The absorption efficiency term allows estimation of the effective dose or the amount of pollutant which crosses the membrane of the exposed tissue (e.g., the lung) and reaches a target organ (e.g., the liver). For many pollutants this type of metabolic data is not available and consequently 100% absorption is a common preliminary assumption in exposure assessments. For well-studied substances such as radionuclides, a methodology for calculation of target organ doses has been developed for bone marrow, lungs, endosteal cells, stomach wall, lower intestine wall, thyroid, liver, kidney, testes and ovaries as well as for the total body. 

The use of AAAs as feed supplements appears an attractive approach either in itself or in combination with pro-, pre- and synbiotics, but the lack of animal feeding studies in which the efficacy of this approach could be determined makes it difficult to assess to what extent a two-barrier (targeting control at both the stomach and intestinal level) approach is commercially feasible. Also, since the viability of probiotics may also be affected by the use of AAA to increase the disinfection activity of the stomach, probiotics may need to be formulated in a way that protects them during stomach transfer. However, its potential should be determined in future research. 

A case can often be made to omit studies as scientifically unnecessary, because it is possible to conduct an adequate risk assessment without them. This is most often the case if the substance decomposes to degradants of known hazardous properties. For example the substance may hydrolyse rapidly to non-toxic products, so the key issue is to establish that this happens rapidly in the stomach before the parent substance can be absorbed. There may then be a case for omitting the expensive long-term animal studies, providing it is also established that there is no dermal or inhalation absorption from these exposure routes. In a similar way, it may be justified to omit ecotoxicity studies on a substance which hydrolyses or otherwise decomposes in the aquatic environment to stable products that have already been tested. 

Mucous membrane tissue lining of nose, mouth, esophagus, stomach, and intestine. Multigeneration Study A toxicity test in which at least three generations of the test organism are exposed to die chemical being assessed. Exposure is usually continuous. 

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