Effect of Selenium Pretreatment in Chronic Mercury Intoxication in Rats

Effect of selenium pretreatment (0.2 mg/kg/day, as sodium selenite), 4 h prior to mercury treatment (0.4 mg/kg/day, as mercuric chloride), administered intraperitoneally, was examined after daily exposure for 20 days’ in rats. Liver, kidney and brain tissues were assayed for malondialdehyde (MDA) level, glutathione (GSH) content and mercury concentration. Mercury induced MDA levels, which was also observed in selenium pretreated animals. Significant reduction in GSH levels was observed in mercury alone and selenium pretreated animals. Mercury accumulation was in the order of kidney, liver and brain. Selenium pretreatment resulted in further enhancement in mercury accumulation in liver and kidney.     

Selenium concentrations in the marine invertebrates Macoma balthica,Mytilus edulis,and Nereis diversicolor

Waders residing in the Dutch Wadden Sea had high selenium concentrations in the tissues. These high concentrations may be a result of a contamination in the food chain, and a selection of marine invertebrate prey animals, the bivalves Macoma balthica and Mytilus edulis and the polychaete Nereis diversicolor, were analyzed for selenium. Selenium concentrations varied by year, season, location, species and size, but the average concentrations (2–6 mg/kg ash free dry weight) remained within the range of known background concentrations in marine invertebrates (1–10 mg/kg DW). However, the highest concentrations approximate the general (sub)toxic level of dietary selenium. The importance of the determination of the selenium compound(s) in marine biota is stressed Macoma had a seasonal variation in selenium concentration that may parallel the reproductive cycle; the highest concentrations (4–5 mg/kg AFDW) were found in the spawning period, the concentration dropped after spawning and in the recovery phase the bivalves were lowest in selenium (2–3 mg/kg AFDW). Intermediate concentrations (3–4 mg/kg AFDW) were measured during the gametogenesis. Concentrations changes in Mytilus corresponded with this pattern.     

高硒与疾病关系的研究进展

硒是人和动物生命过程中必需的微量营养素。但是当机体含硒量超过正常生理需求时,就会引发一系列的疾病。硒中毒包括急性硒中毒和慢性硒中毒。前者一般在临床上比较罕见,其症状主要是呕吐、腹痛、腹泻、心力衰竭,甚或死亡。而后者主要是以中枢神经为主的盲目蹒跚型和硫酸代谢障碍角质素分解坏死为主的碱质病型。目前,职业性环境硒污染在慢性硒中毒中占有相当的比例。鉴于如此情况,有必要采取相应的措施,完善不同种类的硒中毒的防治:1)应及时明确急性硒中毒的诊断,强化和优化抢救方法和措施;2)对地方性慢性硒中毒,设法改善人和畜类的工作及生活环境,在有条件的地方要改良土壤即改变地质结构,加强职业性慢性硒中毒防治劳保配套措施;3)加大对硒中毒的防治宣传力度,加强受威胁人口的忧患意识,做到早期发现、早期诊断、早期治疗。     

2018年洛宁县大骨节病病区与非病区内外环境硒含量监测分析

目的了解大骨节病病区与非病区内外环境硒含量,为大骨节病防治决策提供依据。方法在洛宁县故县镇选择历史重病区岭南村和非病区窑瓦村作为调查点,了解两村历史及目前儿童病情情况,采集两村6~12岁儿童发样各30份;以调查村为中心,排除近三年施用富硒肥的耕地,在东、南、西、北、东北、东南、西北、西南八个方位,8块农田中采集土样;每村按照东、南、西、北、中五个方位各调查2户家庭,共10户,每户采集白面,黄面,黄豆3种主粮,每份样品不少于50 g,检测样品硒含量。结果共采集6~12岁儿童发样49份,粮样60份,土样20份。病区村与非病区村儿童发硒分别为(0.2726±0.0420)mg/kg和(0.3633±0.0744)mg/kg,土硒分别为(0.1185±0.0092)mg/kg和(0.1194±0.0194)mg/kg,黄豆硒分别为(0.0179±0.0084)mg/kg和(0.0212±0.0112)mg/kg,白面硒分别为(0.0094±0.0059)mg/kg和(0.0643±0.0194)mg/kg,黄面硒分别为(0.0116±0.0011)mg/kg和(0.0150±0.0064)mg/kg。儿童发硒,白面,黄面硒均值比较均有统计学意义(P<0.01)。结论大骨节病区内环境硒营养水平基本充足,但外环境缺硒仍然存在,因此应坚持大骨节病监测,提高病区居民膳食中硒营养水平,及时掌握病情变化趋势,巩固防治成效,实现持续消除大骨节病目标。     

Selenium: Significance,and outlook for supplementation

Selenium is a metalloid element with the atomic number 34. It is one of the elements that determine the normal functioning of an organism; it has antioxidant properties and protects the organism against the actions of free radicals and carcinogenic factors. Selenium is an element that fulfills an important physiologic function, but there is a fine line between the concentration that still has beneficial effects on an organism and that at which selenium begins exerting toxic effects. Selenium is involved in the metabolism of hydrogen peroxide and lipid hydroperoxides. It constitutes an integral part of some enzymes, including the glutathione peroxidase (GPx), deiodinase iodothyronine, and thioredoxin reductase (TRxR), which protect cells from the noxious effects of free radicals formed during oxidation processes. Selenium is found in relatively unfamiliar active proteins, generally designated selenoproteins. The significance of the newly identified type SelO, SelT, SelV, and SelI selenoproteins (Sel) still has not been completely elucidated. Studies clearly indicate that selenium-containing yeast can be an effective, safe, and natural source of dietary selenium. In general, the selenium content of various diets can differ significantly depending on the food items and, more importantly their geographical origin and the respective soil selenium content. Thus, it seems advisable to pay attention to the use of this element in the manufacture of high-quality consumer goods, including finished protein-mineral preparations that enrich those diets that are deficient in selenium.     

硒毒性研究进展

硒是人类必需的微量元素,缺乏和过量均对机体有害。对硒的化学性质、以及毒性作用等方面进行简要综述。     

Selenium content and glutathione peroxidase activity in the testis of the maturing rat

In rats fed a diet with 0.25 mg Se/kg the testis selenium content rose during maturation. The value in 4-mo-old animals (7.0 mg Se/kg dry mass; 0.9 mg Se/kg wet mass) was six times higher than that in 20-d-old weanling rats. By comparison, the selenium content in the main selenium pools, muscle and liver, remained unchanged and rose by half, respectively. Due to the increased selenium requirement of the testis during its pubertal maturation the amount of selenium taken up by the male gonads was 50% of the amount deposited in muscle and liver, whereas before and after that period it was about 10%. Feeding animals a low vitamin E diet had no effect on the rise in testis selenium. Glutathione peroxidase activity was twice as high in 4-mo-old animals as in weanling rats. Because only a small percentage of the element in the male gonads was bound to the enzyme, the rise in testis selenium must have been due to other selenium compounds. The selenium content of the spermatozoa was about 21 mg Se/kg dry mass, which by far exceeded the level of this element in other compartments of the rat. The increase in testis selenium content coincided with the beginning of spermatogenesis, and it may therefore ensure the supply of adequate amounts of the element for the spermatozoa.     

Selenium in a Wyoming Grassland Community Receiving Wastewater from an In Situ Uranium Mine

Water, soil, vegetation, grasshoppers, bird eggs, and bird livers collected at a 23.5-ha (58 acres) grassland irrigated with wastewater from an in situ uranium mine (study area) and a reference site in 1998 were analyzed for selenium and other trace elements. Selenium concentrations in the uranium mine wastewater applied onto the grassland ranged from 340 to 450 μg/L. Selenium in the upper 15 cm (6 in) of soil from the irrigated grassland at the mine ranged from 2.6 to 4.2 μg/g dry weight (DW). Mean selenium concentrations in soil and water were 5 and 15 times higher at the study area than at the reference site. Selenium concentrations in grasses and grasshoppers ranged from 6.8 to 24 μg/g and 11 to 20 μg/g DW, respectively. Selenium in red-winged blackbird eggs and livers collected from the study area ranged from 13.2 to 22 μg/g and 33 to 53 μg/g DW, respectively, and concentrations were well in excess of toxic thresholds. Mean selenium concentrations in grasses, grasshoppers, and bird eggs and livers were 5.8 to 30 times higher at the study area than at the reference site. Elevated selenium concentrations in water, soil, grasshoppers, and red-winged blackbird eggs and livers collected from the study area demonstrate that selenium is being mobilized and is bioaccumulating in the food chain. Received: 2 August 2001/Accepted: 24 November 2001     

硒缺乏动物模型的建立及应用

硒是人类和动物维持生命所必需的基本营养元素之一，它在机体内发挥着众多的生物学作用。但是全球缺硒现象非常普遍，硒缺乏成为全球性的普遍问题。为了研究硒缺乏究竟会对人体有何影响，建立缺硒动物模型成为必不可少的关键环节。本文对半个世纪以来国内外低硒动物模型建立的方法以及利用低硒动物模型对硒功能的研究进展作一综述。     

硒对人体健康影响研究进展

硒是人体必需微量元素,在体内以硒代半胱氨酸形式编码合成硒蛋白发挥作用。硒及硒蛋白具有抗氧化、免疫调节等广泛生理功能,缺硒与心脑血管疾病、癌症、糖尿病、神经系统疾病、自身免疫性疾病以及传染病等40多种人类疾病有关。硒营养状况与病毒性疾病密切相关,缺硒导致机体氧化还原及免疫调节失衡,促进病毒感染和复制。缺硒引起氧化应激增加病毒基因组突变率。感染病毒的宿主启动抗氧化和免疫应答反应消耗大量硒,病毒本身表达硒蛋白竞争宿主硒源的同时负反馈调节抑制病毒复制。硒作为治疗药物时,应综合考虑患者硒安全剂量水平以及不同硒化合物的毒性差异。最新研究提示硒状态与新型冠状病毒的感染和病程有关,未来需要结合更多的临床和基础研究数据,探索硒对新冠肺炎（COVID-19）在内的病毒感染疾病的影响。     

How to use the world's scarce selenium resources efficiently to increase the selenium concentration in food

The world's rare selenium resources need to be managed carefully. Selenium is extracted as a by-product of copper mining and there are no deposits that can be mined for selenium alone. Selenium has unique properties as a semi-conductor, making it of special value to industry, but it is also an essential nutrient for humans and animals and may promote plant growth and quality. Selenium deficiency is regarded as a major health problem for 0.5 to 1 billion people worldwide, while an even larger number may consume less selenium than required for optimal protection against cancer, cardiovascular diseases and severe infectious diseases including HIV disease. Efficient recycling of selenium is difficult. Selenium is added in some commercial fertilizers, but only a small proportion is taken up by plants and much of the remainder is lost for future utilization. Large biofortification programmes with selenium added to commercial fertilizers may therefore be a fortification method that is too wasteful to be applied to large areas of our planet. Direct addition of selenium compounds to food (process fortification) can be undertaken by the food industry. If selenomethionine is added directly to food, however, oxidation due to heat processing needs to be avoided. New ways to biofortify food products are needed, and it is generally observed that there is less wastage if selenium is added late in the production chain rather than early. On these bases we have proposed adding selenium-enriched, sprouted cereal grain during food processing as an efficient way to introduce this nutrient into deficient diets. Selenium is a non-renewable resource. There is now an enormous wastage of selenium associated with large-scale mining and industrial processing. We recommend that this must be changed and that much of the selenium that is extracted should be stockpiled for use as a nutrient by future generations.     

Role of selenium in the etiology and prevention of diseases (review)

The data of reports by Russian and foreign authors on the biological effect of selenium are summarized. Some investigations have revealed its high toxic and carcinogenic properties in the selenium-rich biogeochemical provinces. Low-selenium diet has a human unfavourable impact. Recent studies have provided evidence for that is severe selenium deficiency in the environmental objects and foodstuffs virtually throughout the former USSR. At present selenium is recognized to be an essential trace element for human health. Selenium preparations in therapeutical doses have high antioxidative and anticarcinogenic activities. The types of medicinal plant materials that has a pronounced capacity to selectively accumulate selenium from the soil have been defined. Moreover, there are medicinal plants which are selenium concentrators that have high biological accumulation coefficients. Experimental and clinical findings indicate that selenium-containing drugs and medicinal plants should be recommended as an compulsory food additive in selenium-deficient areas for treatment and prophylaxis.     

Selenium intake,mood and other aspects of psychological functioning

Selenium is an essential trace element although the level of selenium in food items reflects the soil in which they were grown and thus varies markedly between different parts of the world. The metabolism of selenium by the brain differs from other organs in that at times of deficiency the brain retains selenium to a greater extent. The preferential retention of selenium in the brain suggests that it plays important functions. To date mood is the clearest example of an aspect of psychological functioning that is modified by selenium intake. Five studies have reported that a low selenium intake was associated with poorer mood. The underlying mechanism is unclear although a response to supplementation was found with doses greater than those needed to produce maximal activity of the selenoprotein glutathione peroxidase. Although the functions of many selenoproteins are unknown some play important roles in anti-oxidant mechanisms. As there are suggestions that oxidative injury plays a role in normal aging, schizophrenia, Parkinson's and Alzheimer's disease, the possible role of selenium is considered. Although there is evidence that supplementation with anti-oxidant vitamins shown some promise with Alzheimer's patients, and in preventing the development of tardive dyskinesia in schizophrenics taking neuroleptics, a role for selenium has been little considered.     

克山病与自然环境和硒营养背景

<正> 克山病是一种病因未明、慢性病程的地方性心肌病。长期以来,提出过许多种病因假说,可归纳为二类,即生物性病因和非生物性病因。后者通常也称为水土病因,它包括有:一为中毒性病因,主要有环境中异常有机物中毒,亚硝酸盐中毒和其他化学元素中毒;一为缺乏病因,主要有缺硒、缺钼、饮食中某些化学物质缺乏与失调。总之通过长期研究与协     

Determination of selenium in food and environmental samples using a gold nanocages/fluorinated graphene nanocomposite modified electrode

Selenium is one of the most attractive nutrient elements for antioxidant, anticancer and immunomodulatory effects, which is obtained from the agricultural food and environment. Herein, a gold nanocages/fluorinated graphene (AuNCs/FG) nanocomposite modified glassy carbon electrode (GCE) was fabricated for the electrochemical determination of selenium by square wave anodic stripping voltammetry. Under the optimal parameters, a wide linear relationship between peak current of selenium on AuNCs/FG/GCE and selenium concentration was observed between 0.002−5.0 mg/L. The method exhibited a low detection limit of 0.27 μg/L. The proposed method was applied successfully for the determination of selenium in agricultural food (tea, rapeseed sprouts, peanut) and environmental (tap water and lake water) samples. The results showed that the average levels of selenium were 0.04−0.27 mg/kg and not detectable, in agricultural food and water, respectively. Therefore, this method has great potential for the monitor of selenium in food and environmental samples.     

Dietary selenium requirement of fingerling channel catfish

Two experiments were conducted in aquaria to determine the minimum dietary selenium requirement of fingerling channel catfish (Ictalurus punctatus). Casein-gelatin diets containing graded levels of supplemental selenium (as Na2SeO3) ranging from 0 to 15 mg/kg were fed to catfish for 15 weeks in experiment 1 to broadly define their selenium requirement and toxicity levels. Although growth of catfish was affected by dietary selenium level, significant differences in weight gain were not easily discernible due to variability among the groups of fish. Weight gain data generally indicated that the basal diet containing 0.06 mg Se/kg diet caused growth depression, and a supplemental selenium level of 15 mg/kg also caused a reduced growth response, which indicated selenium toxicity. Selenium concentrations in edible muscle tissue increased almost linearly with increasing dietary selenium levels. Liver and plasma selenium-dependent glutathione peroxidase (Se GSH-Px) activities indicated the selenium requirement of fingerling channel catfish was between 0.1 and 0.5 mg Se/kg diet. In experiment 2, casein-gelatin diets containing incremental levels of supplemental selenium were fed to catfish for 14 weeks to more precisely determine their minimum dietary selenium requirement. Growth data and liver and plasma Se GSH-Px activities indicated that the minimum selenium requirement of fingerling channel catfish fed adequate vitamin E was 0.25 mg Se/kg dry diet. Based on these data, it appears that selenium supplementation of commercial catfish feeds is warranted.     

Uptake,depuration, and distribution of selenium inDaphnia and its effects on survival and ultrastructure

Selenium is an important essential nutritional trace element which has been shown to provide protection against certain other metal poisoning. However, it is a suspected carcinogen and teratogen. The uptake, depuration, and toxicity of selenium inDaphnia pulex have been examined. The LC₅₀ at 48 and 96 hr for juvenile animals is 0.6 mg/L and 0.1 mg/L respectively, and for adults it is 1.3 mg/L and 0.5 mg/L respectively. Uptake in adult unfed animals is rapid, reaching a maximum at about 12 hr, but depuration is slow. In fed animals, uptake is slower, reaching a maximum at 96 hr, but initial depuration is followed by a slower prolonged loss. Localization in cells is primarily in the cytoplasmic compartment although evidence is presented which suggests nucleolar localization. Ultrastructural damage is detected by 16 hr after exposure and is initially confined to the mitochondria. Dense deposits accumulate in the mitochondrial matrices. The nature of these deposits is unknown; they may represent a calcium-or phosphate-selenium complex. With time, the mitochondria degenerate. It is clear that relatively low concentrations of selenium are toxic to these aquatic organisms and render them incapable of survival in the natural environment. Concentrations higher than those lethal toDaphnia can be expected, at least in local areas, from the burning or conversion of fossil fuels.By acceptance of this article, the publisher or recipient acknowledges the U.S. Government's right to retain a nonexclusive, royalty-free license in and to any copyright covering the article.Research sponsored by the Office of Health and Environmental Research, U.S. Department of Energy, under contract W-7405-eng-26 with the Union Carbide Corporation. T.W.S. was supported in part by Oak Ridge Associated Universities short-visit research participation contract No. S-1951.Undergraduate Research Participant Summer 1977, from Carleton College, Northfield, MN.     

Selenium Intake,Mood and Other Aspects of Psychological Functioning

Abstract

Selenium is an essential trace element although the level of selenium in food items reflects the soil in which they were grown and thus varies markedly between different parts of the world. The metabolism of selenium by the brain differs from other organs in that at times of deficiency the brain retains selenium to a greater extent. The preferential retention of selenium in the brain suggests that it plays important functions. To date mood is the clearest example of an aspect of psychological functioning that is modified by selenium intake. Five studies have reported that a low selenium intake was associated with poorer mood. The underlying mechanism is unclear although a response to supplementation was found with doses greater than those needed to produce maximal activity of the selenoprotein glutathione peroxidase. Although the functions of many selenoproteins are unknown some play important roles in anti-oxidant mechanisms. As there are suggestions that oxidative injury plays a role in normal aging, schizophrenia, Parkinson's and Alzheimer's disease, the possible role of selenium is considered. Although there is evidence that supplementation with anti-oxidant vitamins shown some promise with Alzheimer's patients, and in preventing the development of tardive dyskinesia in schizophrenics taking neuroleptics, a role for selenium has been little considered.     

Selenium in eggs and parental blood of a Dutch marine wader

On the basis of earlier reports on high selenium levels in organs of marine waders from the Dutch Wadden Sea, adverse effects in wader reproduction were anticipated. A local breeding population of the wader Haematopus ostralegus, oystercatcher, was examined for embryotoxicity and selenium levels in eggs and parental blood. Egg and/or blood samples from breeding oystercatchers were obtained also from two reference sites, a Dutch meadow nature reserve and a Norwegian Atlantic island. The blood selenium levels were high in the Dutch marine birds (red blood cells contained 21 mg/kg vs 0.1–1.2 mg/kg dry weight in man), but the highest red blood cell levels were recorded in the red cells of birds sampled at the Norwegian reference site (maximal value 42 mg/kg dry weight). Both the concentrations in eggs from the Wadden Sea and in eggs from inland pastures (about 2 mg/kg dry weight), were at background level and embryotoxicity was not observed. Considering the results, it was concluded that selenium is not a potential threat to the reproduction of waders from the Dutch Wadden Sea, despite the high selenium concentrations in the tissues of the waders foraging in this area. Selenium in egg white was about 1.6 times higher than in yolk. The first egg had a 10% higher egg white and a 19% higher yolk concentration compared to the subsequent eggs in the coastal clutches. Red blood cell levels were about 3.5 times higher in marine feeding birds than in inland feeding birds. Selenium concentrations in the plasma and red blood cells were positively correlated.     

硒、锌对老年性痴呆模型小鼠记忆障碍及丙二醛和一氧化氮含量的影响

目的 观察硒、锌时老年性痴呆(AD)模型小鼠学习记忆障碍及脑组织丙二醛(MDA)、一氧化氮(NO)含量改变的保护作用.方法 50只健康昆明种雄性小鼠随机分为5组,正常对照组(NC).AD模型组、硒(Se,0.0075 mg/kg bw)+AD组、Se(0.0075 mg/kg bw)+Zn(5 mg/kg bw)+模型...