粮食、血中痕量硒蛋氨酸的溴化氰——荧光测定法

本法是利用溴化氰与硒蛋氨酸定量生成硒氰酸甲酯（ＣＨ３ＳｅＣＮ），ＣＨ３ＳｅＣＮ经氯仿萃取后用混合酸消化为Ｓｅ（ＩＶ），再用２，３－二氨基萘测定苤硒脑的荧光值推算硒蛋氨酸含量。本法硒蛋氨酸最低检出限为３ｎｇ／ｇ。用硒含量１０～５００ｎｇ的硒蛋氨酸标准进行测定，其回收率为９１．８％～９７．６％，相对偏差为１．９％～６．３％。样品回收率为９２．３％～９６．７％，相对偏差为２．７％～９．０％。硒胱氨酸、硒半胱氨酸、亚硒酸钠和蛋氨酸对测定无干扰。本法的精密度和准确度均较好。     

某些地方性疾病地区环境中硒的研究──硒的水平及形态

于全国８省市自治区内克山病、大骨节病氟中毒和硒中毒等地方病区，癌症和肝炎地区性的高发区及正常地区内的３０个调查点，采集空气、水、土壤等环境样品，分析硒水平及硒存在形态。调查结果为空气硒：室内以陕西永寿大骨节病区最低３．３ｎｇ／ｍ３，湖北建始县硒中毒区最高６１４．２μｇ／ｍ３；室外空气硒浓度以云南宣威肺癌多发区最低为０．３ｎｇ／ｍ３，仍是建始县的最高３７１．１ｎｇ／ｍ３；室内外空气颗粒物中硒９０％存于＞１０μｍ的细颗粒物中。室外空气中气态硒的百分比（均值为２３．３％）高于室内（均值为９．７％）；颗粒物中不同价态硒分布云南的以Ｓｅ（Ⅵ）为主占６３．５％，陕西以Ｓｅ（Ⅳ）为主占５６．７％，湖北的以Ｓｅ（＜Ⅳ）为主占７９．５％，土壤硒为５８（克山病区）～９０３７ｎｇ／ｇ（硒中毒区），水溶性硒占总硒的百分比以硒中毒、氟中毒、克山病及大骨节病等地区较低，多在５％以下，其它地区的较高，多在１０％以上；其不同价态硒的百分比分布与空气颗粒物的基本一致。水中硒含量大部分在０．３ｎｇ／Ｌ以下，只有高硒和硒中毒地区为１～６８３ｎｇ／Ｌ。不同价态硒的百分比的分布以Ｓｅ（Ⅵ）为主均值７１．４％，Ｓｅ（Ⅳ）均值１８．５％，Ｓｅ（＜Ⅳ）均?     

微量荧光法测定粮食样品中痕量硒－与原荧光法的比较

微量荧光法测定粮食样品中痕量硒，最低检出限为０．３ｎｇ，是原荧光法１／１０；多次测定含硒１５～３９２ｎｇ／ｇ的粮食样品加硒标回收率为９０．６％～９９．３％，对牛肝粉及奶粉标准参考物的测定值均在保证值范围之内；测定含硒１７～２９８ｎｇ／ｇ的粮食样品，变异系数为２．１％～２．６％。另外，微量法还减少了样品及试剂用量，为原法的１／１０，并且省去了原法中去硒硫酸的制备，不仅大大降低了成本，减轻了工作量，而且降低了酸对人体健康的影响和对环境造成的污染。     

微量荧光法测定粮食样品痕量硒—与原荧光法的比较

微量荧光法测定粮食样品中痕量硒，最低检出限为０．３ｎｇ，是原荧光江１／１０；，多次测定含硒１５－３９２ｎｇ／ｇ的粮食样品加硒标加收度为９０．６％－９９．３％，对牛肝粉标准参考物的测定值均在保证值范围之内；测定含硒１７－２９８ｎｇ／ｇ的粮食样品，变异系数为２．１％－２．６％。     

人肝肾甲状腺中硒镉含量的年龄依赖性

检测了６０例尸体标本的硒、镉浓度。其中，肝硒含量两岁为１．５ｎｍｏｌ／ｇ，轻微低于胎儿期（２．９ｎｍｏｌ／ｇ）和成年期（２．１ｎｍｏｌ／ｇ）。胚胎期肾皮质硒含量为２．１ｎｍｏｌ／ｇ、甲状腺为１．６ｎｍｏｌ／ｇ，较胚胎期肝中硒含量低。成年期肾皮质硒含量为５．５ｎｍｏｌ／ｇ，甲状腺为４．３ｎｍｏｌ／ｇ。怀孕期组织镉浓度近于０，出生后肝肾立即开始蓄积。成人期甲状腺中镉浓度明显升高，但成人年龄依赖性无统计     

粮食中硒含量和发硒含量与食管癌发生发展的关系

我们研究玉米中硒含量及发硒含量对食管癌发生发展的影响，结果为：食管癌高发区玉米的硒含量（８３±６．１４ｎｇ／ｇ），高于低发区玉米的硒含量（３５±２．３１ｎｇ／ｇ），有显著性意义（Ｐ＜０．０１）。食管上皮轻度增生，重度增生，食管癌病人发硒含量与正常人发硒含量的比值分别为０．８６０９、０．７３８４、０．６８１２、有显著性意义（Ｐ＜０．０１）。结果提示：食管癌病人体内硒含量下降的原因，可能是食管癌发展的结果。     

荧光光度法测定全血硒的研究

本文介绍用２,３—二氨基萘荧光法在９３０荧光光度计上测定全血硒的探讨,最低检出限为７．９９ｎｇ。用０～０．２００μｇ硒的标准溶液做反复测定,其相关系数为０．９９９６,检出值的相对标准差为３．２～９．２％。测定全血中硒含量的相对标准差为１４．５％,平均...     

四川省部份主粮中霉菌及其毒素污染状况调查

报道了四川省部分地区玉米、小麦、大米３种主要粮食中霉菌侵染状况和伏马菌素Ｂ_１（ＦＢ_１）、杂色曲霉素（ＳＴ）、烟曲霉震颤素（ＦＴ）３种霉菌毒素的污染状况。结果显示３种粮食中霉菌侵染严重,其侵染率分别为９２．３％、８７．２％、７２．４％。菌相以曲霉菌为主,同时检出了产生ＳＴ毒素的杂色曲霉菌。ＦＢ１和ＳＴ在粮食中污染较普遍,ＦＢ_１检出率为１２．８％～１００％,含量１５．２～２７．０ｍｇ／ｎｇ;ＳＴ检出率为３４．３％～５６．９％,含量２４．０～７５．０μｇ／ｋｇ。ＦＴ在粮食中污染率和含量均较低。     

四川省部分地区主粮中杂色曲霉菌及其毒素的污染调查

通过对四川省部分地区大米和小麦两种主粮中杂色曲霉菌（Ａ．ｖ）和杂色曲霉素（ＳＴ）污染调查，结果表明在大米和小麦中，Ａ．ｖ污染率分别为５．５％和１０．５％；ＳＴ污染率为５３．４％和６５．８％；ＳＴ平均含量为１５．５μｇ／ｋｇ和５８．６μｇ／ｋｇ。对不同地区和不同贮藏期粮食进行分析，Ａ．ｖ检出率越高，粮食中ＳＴ污染率和含量越高；贮藏期延长，Ａ．ｖ和ＳＴ检出率及ＳＴ含量增高。实验产毒表明所有Ａ．ｖ菌株均能产生ＳＴ，平均产毒量达７１９０．２μｇ／ｋｇ，证实Ａ．ｖ是ＳＴ形成的主要菌种     

不同硒水平的饮料对大鼠的毒性

本实验的目的是研究不同硒含量的饮料对大鼠的毒性，以期为确定安全补硒剂量及制订食品中硒的卫生标准提供科学依据。实验分为对照组，不同水平亚硒酸钠，不同水平湖北高硒玉米组，共８组。饲养１６－１８周。结果发现饮料硒水平近似的条件下（４μｇ／ｇ，２μｇ／ｇ），吃高硒玉米的动物血硒远远高于吃亚硒酸钠的动物。血硒量前者均分别为后者的２倍（雌性）和４倍（雄性），肝和肾硒前者也高于后者。但动物出现肝脏病变的剂量（４     

谷类粮食中17种元素含量测定

用三电极直流等离子体原子发射光谱仪对大米、玉米、黄豆、小麦以及面粉和麸皮中的１７种元素进行了测定。测定回收率为９１．０％～１０６．８％，变异系数为０．７％～９．８％，符合食品中微量营养素测定的要求。结果显示：谷类粮食中，无机盐和微量元素在黄豆中含量最高。     

微波消解-电感耦合等离子体质谱法测定小麦中的8种元素

目的利用微波消解-电感耦合等离子体质谱法测定小麦中Pb、Cd、As、Cr、Se、Ni、Al、Cu的含量。方法样品经过微波消解后,用ICP-MS法同时测定小麦中Pb、Cd、As、Cr、Se、Ni、Al、Cu的含量,以45 Sc、72Ge、103Rh、209Bi作为内标元素采用电感耦合等离子体质谱法测定,用标准曲线法进行定量。结果小麦中Pb、Cd、As、Cr、Se、Ni、Al、Cu的回收率在95.6%~106.8%,线性相关系数(r)≥0.9995,Pb、Cd、As、Cr、Se、Ni、Al、Cu的检出限分别为0.0049μg/L、0.0023μg/L、0.012μg/L、0.016μg/L、0.026μg/L、0.0099μg/L、0.0070μg/L、0.0027μg/L;生物成分分析标准物质(小麦)的各元素的测定结果均在标准值不确定度范围内;同时对3份小麦样品进行连续6次测定,各元素的相对标准偏差(RSD)≤5%。结论本法线性范围宽、抗干扰能力强、测定周期短,完全满足分析的要求,适用于日常样品的检测。     

四川省克山病的某些流行特点与硒的内外环境调查

<正> 克山病是严重危害我省人民健康的地方性心肌病。自从1961年冬在凉山彝族自治州首次暴发流行以来,我省部分地区曾发生多次流行。1974年以来,在中国医学科学院克山病小分队的帮助下,在我省部分重病区开展了口服亚硒酸钠片预防克山病的工作并取得了显著的效果。为了探索克山病和硒的关系,我站结合我省克山病的某些流行特点,对内外环境中的硒进行了调查。结果如下:     

南京部分市售稻谷和杂粮的Cd Zn Se含量及其健康意义

随机采购了南京市农贸市场部分水稻和杂粮的子粒样品,分别采用火焰原子吸收分光光谱仪、原子荧光光谱仪测定其中Cd、Zn、Se的含量。结果表明:①供试部分粮食的Se含量均低于世界卫生组织推荐的食物硒水平,杂交稻米的Cd含量偏高,且有一半以上的杂粮样本的Cd含量超标,说明居民日常膳食的元素摄入可能存在不平衡;②不同谷类子粒间这些元素含量存在显著差别,以玉米中最低;糙米中的Cd、Zn与除玉米外的杂粮子粒无显著差异;大豆子粒的Cd,Zn含量高于玉米,但Se含量没有显著差异;③供试杂粮中大豆样本有90%超过我国现行杂粮Cd限量标准0.05 mg/kg,而Cd/Zn均未超过Simmons等所提出食物安全值临界值0.015。建议重新拟定杂粮的Cd限量标准。     

Differential responses to selenomethionine supplementation by sex and genotype in healthy adults

A year-long intervention trial was conducted to characterise the responses of multiple biomarkers of Se status in healthy American adults to supplemental selenomethionine (SeMet) and to identify factors affecting those responses. A total of 261 men and women were randomised to four doses of Se (0, 50, 100 or 200 μg/d as L-SeMet) for 12 months. Responses of several biomarkers of Se status (plasma Se, serum selenoprotein P (SEPP1), plasma glutathione peroxidase activity (GPX3), buccal cell Se, urinary Se) were determined relative to genotype of four selenoproteins (GPX1, GPX3, SEPP1, selenoprotein 15), dietary Se intake and parameters of single-carbon metabolism. Results showed that supplemental SeMet did not affect GPX3 activity or SEPP1 concentration, but produced significant, dose-dependent increases in the Se contents of plasma, urine and buccal cells, each of which plateaued by 9-12 months and was linearly related to effective Se dose (μg/d per kg0·75). The increase in urinary Se excretion was greater for women than men, and for individuals of the GPX1 679 T/T genotype than for those of the GPX1 679 C/C genotype. It is concluded that the most responsive Se-biomarkers in this non-deficient cohort were those related to body Se pools: plasma, buccal cell and urinary Se concentrations. Changes in plasma Se resulted from increases in its non-specific component and were affected by both sex and GPX1 genotype. In a cohort of relatively high Se status, the Se intake (as SeMet) required to support plasma Se concentration at a target level (Se(pl-target)) is: Se(in) = [(Se(pl - target) - Se(pl))/(18.2ng d kg?.??/ml per mu g)] .     

Determination of molybdenum in foods and human milk, and an estimate of average molybdenum intake in the Japanese population

To evaluate the molybdenum (Mo) status in the Japanese population, the Mo content in various foods and human milk was determined using inductively coupled plasma mass spectrometry (ICP-MS) and the average Mo intake was estimated. The difference in Mo content among food groups was marked; Mo levels in several plant foods such as cereals were more than 0.5 g/g while those in most animal foods were less than 0.1 microg/g. In particular, Mo contents in several samples of seeds and pulses were more than mixeo 1 mirog/g. The variation in Mo contents in each type of cereal was also conspicuous. Based on the present quantification of Mo in foods and the recent National Nutrition Survey in Japan, the average Mo intake of the Japanese population was estimated as 225 microg/d/capita. The principal Mo source in the Japanese diet was rice followed by soybean products, and approximately 90% of the Mo intake was derived from plant foods. Seventeen human milk samples were collected from 3 healthy mothers once or twice a month from 96 to 327 d after delivery. The median and range of Mo in human milk samples were 4.5 ng/mL and 2.0 to 8.8 ng/mL, respectively. Mo levels in Japanese formula milk were 2 to 3 ng/mL. Based on the Mo levels in human milk and formula milk, the Mo intake of Japanese infants was estimated to be 2 to 4 microg/d/capita.     

山东省某轻稀土矿区粮食中稀土元素含量与健康风险

目的了解山东某轻稀土矿区与非矿区粮食中稀土元素含量及其健康风险。方法于2014年7—10月,采集调查区域内村民自己种植的粮食(小麦、玉米和大豆)样品339份,采用电感藕合等离子体质谱仪(ICP-MS)测定15种稀土元素的含量。结果矿区粮食中总稀土元素含量为9.85~4 268.39μg/kg,中位数为82.47μg/kg;非矿区粮食中总稀土元素含量为1.55~2 662.31μg/kg,中位数为54.75μg/kg。矿区和非矿区粮食中稀土元素含量差异无统计学意义(P0.05)。矿区和非矿区均为小麦稀土元素含量最高(128.79μg/kg和85.14μg/kg),玉米最低(44.89μg/kg和37.95μg/kg)。粮食中稀土元素以富集轻稀土元素为特征。通过粮食摄入的稀土元素远小于健康指导值。结论矿区和非矿区粮食中稀土元素含量无差异,以轻稀土元素为主,通过小麦、玉米、大豆摄入的稀土元素不会危害人体健康。     

食品中黄曲霉毒素B_1单克隆抗体酶联免疫测定方法的建立及初步应用

用抗 AFB_1的单克隆抗体 AFB_1-2H8,建立了检测食品(玉米、花生、小麦、大米、植物油)中 AFB_1的 ELISA 间接竞争法。该方法最低检出浓度为0.01ng/g,敏感范围为0.2～50ng/g,平均回收率为83.0%～110.3%,精密度为2.0%～24.3%。用该法测定了分布于淮河以北地区的145份样品,并对25份植物油样品用 TLC 和 ELISA 两种方法进行了对比测定。     

Selenium from selenium-rich Spirulina is less bioavailable than selenium from sodium selenite and selenomethionine in selenium-deficient rats

The bioavailabilty of selenium (Se) from selenium-rich Spirulina (SeSp) was assessed in Se-deficient rats by measuring tissue Se accumulation and glutathione peroxidase (GSH-Px) activity. For 42 d, rats were subjected to dietary Se depletion by consumption of a Torula yeast (TY)-based diet with no Se; controls were fed the same diet supplemented with 75 microg Se/kg diet as sodium selenite. Se-deficient rats were then repleted with Se (75 microg/kg) by the addition of sodium selenite, selenomethionine (SeMet) or SeSp to the TY basal diet. Selenium speciation in SeSp emphasized the quasi-absence of selenite (2% of total Se); organic Se comprised SeMet (approximately 18%), with the majority present in the form of two selenoproteins (20-30 kDa and 80 kDa). Gross absorption of Se from SeSp was significantly lower than from free SeMet and sodium selenite. SeMet was less effective than sodium selenite in restoring Se concentration in the liver but not in kidney. SeSp was always much less effective. Similarly, Se from SeSp was less effective than the other forms of Se in restoring GSH-Px activity, except in plasma and red blood cells where no differences were noted among the three sources. This was confirmed by measuring the bioavailability of Se by slope-ratio analysis using selenite as the reference form of Se. Although Se from SeSp did not replenish Se concentration and GSH-Px activity in most tissues to the same degree as the other forms of Se, we conclude that it is biologically useful and differently metabolized due to its chemical form.