Gastrointestinal Absorption, Distribution, and Excretion of Radiocesium

Stara, Jerry F.; Wolfangel, Robert G.; Bruckner, Benjamin H.; Moore, Wellington

doi:10.1016/b978-0-08-015721-4.50020-3

Cited by 2 publications

(1 citation statement)

References 24 publications

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“…This vulnerability possibly reflects soil ingestion during grazing. Furthermore, Stara (1971) has reported that the extent of GI uptake of elements such as cesium by the ruminant (80%) is not much lower than monogastrics (90% ). These Proceedings discuss the topic elsewhere.…”

Section: Interspecies Differences In the Gi Absorption Of Leadmentioning

confidence: 99%

Gastro-Intestinal Absorption of Lead in Children and Adults: Overview of Biological and Biophysico-Chemical Aspects

Mushak

1991

Chemical Speciation & Bioavailability

102

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Intake and uptake of lead in the general population is mainly via the gastro-intestinal (GI) tract. Those biological and biophysico-chemical factors operating in the Gl tract are the main determinants of Pb bioavailability. They include sites of Pb uptake, the physiology of uptake/transport to blood, the stage of development, interactions of Pb with nutrients, and Gl biochemical transformations of ingested material. Lead uptake occurs as ion or complex, from micelles and perhaps by pinocytosis in the infant. Uptake is mainly via the duodenum but other sites can participate, e.g. ileum (pinocytosis) and colon. Transport to blood is by active, carrier-mediated transport and passive diffusion. Uptake may include movement through intercellular tight junctions. Lead uptake is affected by nutrients in the Gl tract, operating synergistically or antagonistically. Iron and calcium interactions are most important and augment those also occurring in vivo in tissues. Liberation of lead from diverse ingested media, e.g. food, paint, soil and dust, mining waste, is affected by their chemical/physical forms, hydrolytic and oxidative processes in gastric fluid and other Gl sites. Such changes in vivo are poorly simulated by in vitro tests. The downward revision of blood lead (Pb-8) levels considered 'safe', to about 0.5 ~mol C 1 (10 ~g dL-t) or lower, causes even sources of moderately bioavailable Pb to become important.

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Section: Interspecies Differences In the Gi Absorption Of Leadmentioning

confidence: 99%

Gastro-Intestinal Absorption of Lead in Children and Adults: Overview of Biological and Biophysico-Chemical Aspects

Mushak

1991

Chemical Speciation & Bioavailability

102

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Gastrointestinal and Dermal Absorption: Interspecies Differences

Calabrese

1984

Drug Metabolism Reviews

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It has been repeatedly demonstrated that there are considerable interspecies differences with respect to the dermal absorptions of a chemically diverse set of substances, ranging from ionic substances to complex organic molecules, some of which are of great relevance to environmental/occupational health (e.g., the organophosphate insecticides). In general, human skin was found to be much less permeable to the substances evaluated when compared to rabbit and rodent skin; however, the pig and monkey appear to most closely simulate the absorption capabilities of human skin for a variety of substances. Unfortunately, no truly systematic evaluations of numerous classes of compounds have been made via interspecies comparisons. Thus, even though the data derived until now are very consistent, one could argue that strong general conclusions with respect to interspecies differences in dermal absorption cannot yet be made because the substances evaluated thus far may not be sufficiently representative. Clearly, further research along these lines is required.

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Gastrointestinal Absorption, Distribution, and Excretion of Radiocesium

Cited by 2 publications

References 24 publications

Gastro-Intestinal Absorption of Lead in Children and Adults: Overview of Biological and Biophysico-Chemical Aspects

Gastro-Intestinal Absorption of Lead in Children and Adults: Overview of Biological and Biophysico-Chemical Aspects

Gastrointestinal and Dermal Absorption: Interspecies Differences

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