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Hypothyroidism
Published in Vincenzo Berghella, Maternal-Fetal Evidence Based Guidelines, 2022
Recently, trace element selenium has been shown to reduce the incidence of hypothyroidism during pregnancy and postpartum periods [12]. Selenoproteins act as antioxidants and decrease thyroid inflammation in autoimmune thyroiditis by reducing TPOAb titers. Up to 30% of women with TPOAb develop permanent hypothyroidism following postpartum thyroid dysfunction [13]. This may suggest a preventive role of selenomethionine supplementation in autoimmune thyroid dysfunction.
Ultratrace Minerals
Published in Luke R. Bucci, Nutrition Applied to Injury Rehabilitation and Sports Medicine, 2020
Selenium is found in two basic forms — inorganic and organic. Inorganic selenium is encountered as water-soluble selenites () and selenates () found in water supplies.1054 Organic selenium is found as selenomethionine and selenocysteine in plant and animal foods. Selenomethionine is the major organic form of selenium in the diet. Selenomethionine is the major storage form of selenium in the body and is converted to selenocysteine in a highly regulated manner for inclusion into GPx enzymes. Selenocysteine can also be produced from inorganic sources. At present, supplemental forms of selenium include sodium selenite, sodium selenate, selenomethionine, and selenium-enriched yeast.
Other Cyclotron Radionuclides
Published in Frank Helus, Lelio G. Colombetti, Radionuclides Production, 2019
Selenium is regarded as an essential bioelement, and some seleno-organic compounds, such as selenomethionine, exist in animal body. Selenomethionine labeled with reactor-made 75Se has been used for pancreas diagnosis in spite of its long life (120 d). 73Se is a short lived positron emitter obtainable in no-carrier-added state. It is thus more suitable in nuclear medicine, though it decays into radioactive 73As (EC, 80 d). Production of 73Se as well as organic labeling with it have been studied. The reactions Ge + 3He →73Se, Ge + α→73Se and 75As(p,3n)73Se can be used. The excitation functions for them were measured together with those for simultaneous formation of 72Se (8.4 d) and 75Se.57 The 75As(p,3n)73Se reaction gives the highest yield and product purity. The thick target yields for these reactions are shown in Table 7.57 As the germanium target, metallic germanium or GeO2 are used. For arsenic target, some descriptions are given in Section I.D.3. From the targets, 73Se can be separated either by volatilization under radio-frequency fusion or by some other wet processes.57,58 With a minute amount (several micrograms) of carrier, 73Se can be obtained as red selenium solution in an organic solvent.57
Biosynthesis of nano selenium in plants
Published in Artificial Cells, Nanomedicine, and Biotechnology, 2023
Jonas Verstegen, Klaus Günther
Selenium is an element of the chalcogenide group and one of the most versatile trace elements. In contrast to other species, selenium is not considered essential for plants [1,2]. While among other mammals humans rely on selenocysteine (SeCys) in the catalytic centre of enzymes like glutathione peroxidase (GPx) or thioredoxin reductase (TrxR), the plant homologues contain cysteine (Cys) [3]. Though not considered essential, selenium can still have beneficial impact on plants and increase the activity of said enzymes while also improving the resistance against cold, drought and metallic stress [4]. Still, selenium accumulation bears the danger to impair cell integrity and metabolism. Toxic effects of selenium in plants are mostly caused by unintentional incorporation of SeCys and selenomethionine (SeMet) into proteins [5], but also include oxidative and nitrosative stress [2].
Sex-specific relationship between blood selenium levels and platelet count in a large cohort representative of the United States population
Published in Platelets, 2022
Selenium metabolism is complex and yet to be fully explored. In humans, food is the primary source of selenium intake with four molecules (selenocysteine, selenomethionine, selenite, and selenate) accounting for most of the bioavailable selenium in food [3]. Recommended daily intake for adults is between 55 and 70 μg; intake less than 12μg/day is associated with severe selenium deficiency while an intake above 500 μg/day results in selenium toxicity [16]. The absorption of selenium occurs mainly in the lower part of the small intestine and the gut microbiome may play a role in selenium bioavailability [17]. Once absorbed, selenium is rapidly taken up from circulation by tissues with the highest selenium concentrations found in kidneys, liver, spleen, pancreas, and heart. Excess selenium is excreted in the urine. In the tissues, selenium-based two rare amino acids, selenocysteine and selenomethionine, are incorporated into selenoproteins [18].
Brazil nut prevents oxidative DNA damage in type 2 diabetes patients
Published in Drug and Chemical Toxicology, 2022
Tamires Pavei Macan, Thais Aquino de Amorim, Adriani Paganini Damiani, Ângela Caroline da Luz Beretta, Marina Lummertz Magenis, Thais Ceresér Vilela, João Paulo Teixeira, Vanessa Moraes de Andrade
The Brazil nut (Bertholletia excelsa, H.B.K.) presents high concentration of proteins, fibers, and bioactive compounds, especially phenolic compounds, sterols and tocopherols, and favorable fatty acids composition (Cardoso et al.2017). At the moment, this Amazonian nut is considered the richest known source of dietary selenium (Se) (Finley 2005, Cardoso et al. 2017). This mineral is presented as selenomethionine that is an organic form of Se highly bioavailable (Thomson et al.2008). This oleaginous fruit is produced without pesticides (Rockwell et al.2015), harvested usually by local people, and the commercialization of this nut provides one of the major sources of income for many Amazonian indigenous and riverine communities (Ribeiro et al.2014), making this a sustainable agriculture. It is known that micronutrients ingestion from food sources is better than alternative supplementation practices when the goal is to improve the human nutritional status, since food is low-cost, sustainable and has a lower risk of toxicity (Finley 2005, Kieliszek 2019). Furthermore, this nut has been associated with a wide range of health benefits and has been put in the spotlight as an effective and low-cost alternative to improve the Se status (Cardoso et al.2017).