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Selenium

About: Selenium is a research topic. Over the lifetime, 21192 publications have been published within this topic receiving 429715 citations. The topic is also known as: Se & selen.


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Journal ArticleDOI
TL;DR: Findings indicate that selenomethionine is considerably more teratogenic and generally more embryotoxic than sodium selenite, probably due to higher uptake of selenometrichions in hatchlings.
Abstract: Mallards (Anas platyrhynchos) were fed a control diet, diets containing 1, 5, 10, or 25 ppm Se as sodium selenite, or a diet containing 10 ppm Se as seleno-DL-methionine in the first of two experiments. Selenium at 10 ppm as selenomethionine or 25 ppm as sodium selenite caused a 40-44% decrease in the total number of eggs that hatched compared to controls. Selenium at 25 ppm (sodium selenite) resulted in a 19% decrease in mean embryonic weight at 18 d of incubation, accompanied by a 6% decrease in crown-rump length. Ten parts per million Se as selenomethionine was more teratogenic than sodium selenite at 25 ppm. Selenomethionine (10 ppm Se) resulted in an incidence of 13.1% malformations that were often multiple, whereas sodium selenite (10 and 25 ppm Se) resulted in 3.6 and 4.2% malformations. The teratogenicity of selenomethionine was confirmed in a second experiment in which mallards received 1, 2, 4, 8, or 16 ppm Se as selenomethionine, resulting in 0.9, 0.5, 1.4, 6.8, and 67.9% malformations, respectively. These malformations included hydrocephaly, microphthalmia, lower bill defects, and foot defects with ectrodactyly. Both forms of selenium increased the incidence of edema and stunted embryonic growth. Selenomethionine (10 ppm Se) resulted in a significant increase of approximately 40% in plasma glutathione peroxidase activity and a 70% increase in sorbitol dehydrogenase activity (indicative of hepatotoxicity) in hatchlings. Sodium selenite (25 ppm Se) resulted in fourfold elevation in plasma uric acid concentration, indicative of renal alteration. Selenomethionine accumulated much better in eggs than did sodium selenite. These findings indicate that selenomethionine is considerably more teratogenic and generally more embryotoxic than sodium selenite, probably due to higher uptake of selenomethionine.

119 citations

Journal ArticleDOI
TL;DR: It follows that not all men will necessarily benefit from increasing their selenium intake and that measurement of baseline nutrient status should be required for all individuals in prevention trials to avoid oversupplementation.
Abstract: Daily supplementation with the essential trace mineral selenium significantly reduced prostate cancer risk in men in the Nutritional Prevention of Cancer Trial. However, the optimal intake of selenium for prostate cancer prevention is unknown. We hypothesized that selenium significantly regulates the extent of genotoxic damage within the aging prostate and that the relationship between dietary selenium intake and DNA damage is non-linear, i.e. more selenium is not necessarily better. To test this hypothesis, we conducted a randomized feeding trial in which 49 elderly beagle dogs (physiologically equivalent to 62-69-year-old men) received nutritionally adequate or supranutritional levels of selenium for 7 months, in order to mimic the range of dietary selenium intake of men in the United States. Our results demonstrate an intriguing U-shaped dose-response relationship between selenium status (toenail selenium concentration) and the extent of DNA damage (alkaline Comet assay) within the prostate. Further, we demonstrate that the concentration of selenium that minimizes DNA damage in the aging dog prostate remarkably parallels the selenium concentration in men that minimizes prostate cancer risk. By studying elderly dogs, the only non-human animal model of spontaneous prostate cancer, we have established a new approach to bridge the gap between laboratory and human studies that can be used to select the appropriate dose of anticancer agents for large-scale human cancer prevention trials. From the U-shaped dose-response, it follows that not all men will necessarily benefit from increasing their selenium intake and that measurement of baseline nutrient status should be required for all individuals in prevention trials to avoid oversupplementation.

119 citations

Journal ArticleDOI
TL;DR: Brazil nuts (Bertholletia excelsa) natively contain very high concentrations of selenium, which have been associated with protection against tumor development in laboratory animal studies, and the toxicology of Brazil nut consumption is discussed.

119 citations

Journal ArticleDOI
TL;DR: Semi-metals (boron, silicon, arsenic and selenium) form organo-metal compounds, some of which are found in nature and affect the physiology of living organisms, and are often used as analogues of important pharmacological sulfur compounds.

119 citations

Journal ArticleDOI
TL;DR: In this article, a procedure for sediments and planktonic material has been developed that uses a multistep nitric/perchloric acids digestion to solubilize total selenium and a weak sodium hydroxide treatment to release selenite and selenate.
Abstract: Selenium can exist in a variety of chemical forms in the suspended particles and bottom sediments of natural waters. A procedure for sediments and planktonic material has been developed that uses a multistep nitric/perchloric acids digestion to solubilize total selenium and a weak sodium hydroxide treatment to release selenite and selenate. The solubilized selenium species are determined by a selective hydride generation/atomic absorption technique. Accuracy was verified by using a combination of standard reference materials, radiotracers, and existing sediment leach methods. For field and reference samples the average precision (relative standard deviation) for total selenium determinations is 8.8% (n = 8 samples) and 19.3% for selenite + selenate determinations (n = 6 samples). The detection limit for total particulate selenium is 10 ng/g using a sample size of 0.2 g. The method has been used on a variety of plankton, planktonic detritus, and sediment samples. 22 references, 1 figure, 3 tables.

119 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20231,062
20222,045
2021554
2020569
2019705
2018792