Selenium requirement

Wagner R, JR Andreesen (1979) Selenium requirement for active xanthine dehydrgenase from Clostridium acidiurici and Clostridium cylindrosporum. Arch Microbiol 121 255-260. 

Situnayake et al., 1991). No correlation between disease activity and serum vitamin E concentrations was found, but it was su ested that such patients might suffer a reduced antioxidant capacity. However, it is conceivable that a decreased serum antioxidant status is a primary event in the evolution of RA. Recent studies (Heliovaara etal., 1994) have demonstrated that lowered levels of vitamin E, /3-carotene and selenium (required for glutathione peroxidase) together may be a risk fector for subsequent development of RA. 

It is interesting to compare S.. S and Se.. Se cation radicals in terms of oxidation. In general, oxidation of selenium requires considerably less energy than oxidation of sulfur. This means that Se.. Se species are more stable thermodynamically than their S.. S analogs. Nevertheless, Se.. Se species are readily oxidized to the corresponding dications. The reaction in Scheme 3-20 is an illustrative example (Asmus 2000) ... 

XI. Selenium Requirements and Recommended Dietary Intakes XII. Summary and Conclusions References... 

As with other solutes, sampling natural waters for arsenic and selenium require (i) the sample to... 

Selenium-requiring proteins indude GSH peroxidase, deiodinase, selenoprotein P, and selenoprotein W, GSH peroxidase is vital for the removal of certain forms of toxic oxygen, i.o, lipid peroxidides and hydrogen peroxide. 5 -Deiodinase is used for the synthesis of thyroid hormone. The functions of selenoproteins P and W are not known,... 

Selenium, Se (its red modification), has been successfully employed for dehydrogenations of six-membered rings to aromatic systems. Compared with sulfur, selenium requires higher temperatures. Consequently, side reactions such as rearrangements occur [493]. 

Selenium-Requiring Enzymes Glutathione and Cancer Glutati ione and Aldehyde Metabolism Glutathione in the Glomerular Filtrate Selenium Nutrition Otiier Inoiganic Nutrients References Bibliography... 

Despite the clear-cut demonstrations of selenium accumulation by plants and metabolism by both plants, fungi and bacteria (Table 1.8), evidence for a nutritional selenium requirement by these groups of organisms is equivocal (Shrift, 1973). It is possible, however, that formation of organic-selenium compounds may be a mechanism for counteracting selenium toxicity (Doran and Alexander, 1977). 

Smith, AM Ohio State University Influence of gender and life cycle on selenium requirements and metabolism CRIS/UDSA2001... 

Duffield AJ, Thomson CD, Hill KE, et al. 1999. An estimation of selenium requirements for New Zealanders. Am J Clin Nutr 70 896-903. 

Yang G, Ge K, Chen J, et al. 1988. Selenium-related endemic diseases and the daily selenium requirement of humans. In Bourne GH, ed. World review of nutrition and dietetics. Sociological and medical aspects. Vol. 55. Basel Karger, 98-152. 

Selenium was first used as dehydrogenation catalyst by Diels,127 when by this method he established cyclopenta[a]phenanthrene as the parent skeleton of steroids, bile acids, steroid hormones, and other natural products. Dehydrogenation by selenium requires the use of higher temperatures and is thus often accompanied by side reactions. 

The northern parts of Europe produce selenium-poor foods. Selenium consumption in Germany is low, on average, amounting to between 40 and 90 jg per day. The normal selenium requirement of women and men is not met in every case, and selenium deficiency in German is common (Drobner 1997, Anke et al. 2002, 2003). Vegetarians, on average, take in less selenium than people with mixed diets. 

Human Selenium Requirements and Recommended Dietary Intakes All intake recommendations depend on the definitions used to derive them and the available scientific information. Accordingly, they are not to be considered final as they are periodically re-evaluated and revised. 

Levander OA (1987) Dietary Selenium Requirements Minimal and Optimal Intake and Disadvantages in the Use of Supplements. 2nd Nordic Symposium on Trace Elements in Human Health and Disease, Odense. Abstract Mini-Symposium No. 12 and Round-Table Discussion on Mineral Supplementation. WHO Regional Office for Europe, Copenhagen. Environ Health 26 87-90. 

Use an internet search engine (such as http //www.google. com) to locate information on dietary requirements for selenium. What are the daily minimum and maximum amounts of selenium required What are some natural sources of selenium in our diets What are some of the symptoms that might be experienced if one s diet has too little selenium What if it has too much selenium ... 

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