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.

Distribution of selenium and glutathione peroxidase in the rat.

Abstract: The selenium content was determined in the adrenals, brain, erythrocytes, femur, hair, heart, kidneys, lungs, muscle, pancreas, plasma, spleen, testes, and thymus of rats, which had been fed a commercial rat diet containing 03 mg Se/kg diet In the plasma, the erythrocytes, and the soluble fraction of the tissues (with the exception of femur and hair) the activity of the glutathione peroxidase (GSH-Px) was measured, using both hydrogen peroxide and t-butyl hydroperoxide as substrates From the masses of the tissues and the values for the selenium content and the GSH-Px activity, the distribution of the element and the enzyme in the body was calculated For selenium the main pools were the muscle and the liver, and for the GSH-Px, the liver and the erythrocytes By comparing the selenium content and the GSH-Px activity the percentage of the tissue selenium, which was bound to the enzyme in the soluble tissue fraction, was estimated This percentage differed considerably from tissue to tissue, the highest value being found in the erythrocytes and the smallest in the testes According to this estimation the majority of the selenium in the rat is not contained in the GSH-Px but in other compounds

Effects of high doses of selenium, as sodium selenite, in septic shock: a placebo-controlled, randomized, double-blind, phase II study

Abstract: Sepsis is associated with the generation of oxygen free radicals and (lacking) decreased selenium plasma concentrations. High doses of sodium selenite might reduce inflammation by a direct pro-oxidative effect and may increase antioxidant cell capacities by selenium incorporation into selenoenzymes. We investigated the effects of a continuous administration of high doses of selenium in septic shock patients. A prospective, multicentre, placebo-controlled, randomized, double-blind study was performed with an intention-to-treat analysis in severe septic shock patients with documented infection. Patients received, for 10 days, selenium as sodium selenite (4,000 μg on the first day, 1,000 μg/day on the nine following days) or matching placebo using continuous intravenous infusion. The primary endpoint was the time to vasopressor therapy withdrawal. The duration of mechanical ventilation, the mortality rates in the intensive care unit, at hospital discharge, and at 7, 14, 28 and 180 days and 1 year after randomization, and adverse events were recorded. Sixty patients were included (placebo, n = 29; selenium, n = 31). The median time to vasopressor therapy withdrawal was 7 days in both groups (95% confidence interval = 5–8 and 6–9 in the placebo and selenium groups, respectively; log-rank, P = 0.713). The median duration of mechanical ventilation was 14 days and 19 days in the placebo and selenium groups, respectively (P = 0.762). Mortality rates did not significantly differ between groups at any time point. Rates of adverse events were similar in the two groups. Continuous infusion of selenium as sodium selenite (4,000 μg on the first day, 1,000 μg/day on the nine following days) had no obvious toxicity but did not improve the clinical outcome in septic shock patients. Trial Registration = NCT00207844.

On the Mechanism of Selenium Tolerance in Selenium-Accumulating Plants

Abstract: Selected members of the genus Astragulus (Fabaceae) are known for their ability to accumulate high levels of selenium, mainly in the form of Se-methyl-selenocysteine. With the aid of cell cultures we have investigated the molecular basis for selenium tolerance of these plants. It is shown that cultured cells from a selenium-accumulating Astragalus species synthesize Se-methyl-selenocysteine in contrast to those of a non-accumulating species and do not unspecifically incorporate selenium into proteins. The purification and biochemical characterization of a selenocysteine methyltransferase from cultured Astragalus bisculatus cells is described, which does not accept cysteine as a substrate. We propose that this enzyme plays a crucial role in conferring selenium tolerance.