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.

Deposition of dietary organic and inorganic selenium in rat erythrocyte proteins.

Abstract: The deposition of selenium (Se) in erythrocyte proteins was studied in rats fed Se as sodium selenite, selenocystine, selenomethionine (Se-Met), high Se wheat or selenium-enriched yeast. Ion-exchange chromatography of acid hydrolyzates of selenium-enriched yeast, high Se wheat and intrinsically labeled 75Se wheat indicated that the majority of the Se was present as Se-Met. Gel filtration (Sephadex G-150) of erythrocyte lysates revealed that Se was deposited mainly in two proteins, glutathione peroxidase (GPx) and hemoglobin (Hb). When selenite or selenocystine was the dietary form of Se, the majority of the erythrocyte Se was present with GPx, but when the Se was supplied from either Se-Met, yeast or wheat, it was deposited to a greater extent in Hb than GPx. Injection of 75Se as either Se-Met or selenite gave results consistent with the feeding studies. 75Se-labeled selenite injection resulted in labeling of primarily GPx, but 75Se-Met injection labeled predominantly Hb. Hence, the dietary forms of Se influence the relative distribution of Se between GPx and Hb in erythrocytes, and this may be a factor contributing to the difference between human and animal erythrocytes.

Selenium biochemistry and cancer: a review of the literature.

Abstract: In recent years, the role of selenium in the prevention of a number of degenerative conditions including cancer, inflammatory diseases, thyroid function, cardiovascular disease, neurological diseases, aging, infertility, and infections, has been established by laboratory experiments, clinical trials, and epidemiological data. Most of the effects in these conditions are related to the function of selenium in antioxidant enzyme systems. Replenishing selenium in deficiency conditions appears to have immune-stimulating effects, particularly in patients undergoing chemotherapy. However, increasing the levels of selenoprotein antioxidant enzymes (glutathione peroxidase, thioredoxin reductase, etc.) appears to be only one of many ways in which selenium-based metabolites contribute to normal cellular growth and function. Animal data, epidemiological data, and intervention trials have shown a clear role for selenium compounds in both prevention of specific cancers and antitumorigenic effects in postinitiation phases of cancer. (Altern Med Rev 2004;9(3):239-258)

Micro- and Mesoporous Carbide-Derived Carbon–Selenium Cathodes for High-Performance Lithium Selenium Batteries

Abstract: Nanocomposites of selenium (Se) and ordered mesoporous silicon carbide-derived carbon (OM-SiC-CDC) are prepared for the first time and studied as cathodes for lithium-selenium (Li-Se) batteries. The higher concentration of Li salt in the electrolytes greatly improves Se utilization and cell cycle stability. Se-CDC shows significantly better performance characteristics than Se-activated carbon nanocomposites with similar physical properties. Se-CDC also exhibits better rate performance and cycle stability compared to similarly produced sulfur (S)–CDC for Li/S batteries.

Organoselenium chemistry : modern developments in organic synthesis

Abstract: and General Aspects.- Electrophilic Selenium, Selenocyclizations.- Nucleophilic Selenium.- Radical Reactions Using Selenium Precursors.- Selenium-Stabilized Carbanions.- Selenium at Higher Oxidation State.- Selenocarbonyls.- Selenoxide Elimination and [2,3]Sigmatropic Rearrangement.- Selenium Compounds as Ligands and Catalysts.

Selenium modulates oxidative stress-induced cell apoptosis in human myeloid HL-60 cells through regulation of calcium release and caspase-3 and -9 activities.

Abstract: Selenium is an essential chemopreventive antioxidant element to oxidative stress, although high concentrations of selenium induce toxic and oxidative effects on the human body. However, the mechanisms behind these effects remain elusive. We investigated toxic effects of different selenium concentrations in human promyelocytic leukemia HL-60 cells by evaluating Ca2+ mobilization, cell viability and caspase-3 and -9 activities at different sample times. We found the toxic concentration and toxic time of H2O2 as 100 μm and 10 h on cell viability in the cells using four different concentrations of H2O2 (1 μm–1 mm) and six different incubation times (30 min, 1, 2, 5, 10, 24 h). Then, we found the therapeutic concentration of selenium to be 200 nm by cells incubated in eight different concentrations of selenium (10 nm–1 mm) for 1 h. We measured Ca2+ release, cell viability and caspase-3 and -9 activities in cells incubated with high and low selenium concentrations at 30 min and 1, 2, 5, 10 and 24 h. Selenium (200 nm) elicited mild endoplasmic reticulum stress and mediated cell survival by modulating Ca2+ release, the caspases and cell apoptosis, whereas selenium concentrations as high as 1 mm induced severe endoplasmic reticulum stress and caused cell death by activating modulating Ca2+ release, the caspases and cell apoptosis. In conclusion, these results explained the molecular mechanisms of the chemoprotective effect of different concentrations of selenium on oxidative stress-induced apoptosis.