碘酸钾极谱体系测定西红柿中的微量硒

目的试验选择了碘酸钾极谱体系测定食品中微量硒的方法。方法采用微分电位溶出仪(MP-1型),进行了包括实验温度、反应时间以及试剂用量等选择试验。结果用于番茄样品微量硒的测定,所得线性回归方程为Y=12810X+8.7024,R2=0.9996。硒的最小检出量为0.08μg.L-1,相对标准偏差为1.3%,加标回收率为93%～99%。结论该方法测定食品中微量硒结果满意;该法具有灵敏度高,准确度好,仪器简单,操作简便等特点。     

The Role of Minerals in the Optimal Functioning of the Immune System

Minerals fulfil a wide variety of functions in the optimal functioning of the immune system. This review reports on the minerals that are essential for the immune system’s function and inflammation regulation. We also discuss nutritional aspects of optimized mineral supply. The supply of minerals is important for the optimal function of the innate immune system as well as for components of adaptive immune defense; this involves defense mechanisms against pathogens in addition to the long-term balance of pro- and anti-inflammatory regulation. Generally, a balanced diet is sufficient to supply the required balance of minerals to help support the immune system. Although a mineral deficiency is rare, there are nevertheless at-risk groups who should pay attention to ensure they are receiving a sufficient supply of minerals such as magnesium, zinc, copper, iron, and selenium. A deficiency in any of these minerals could temporarily reduce immune competence, or even disrupt systemic inflammation regulation in the long term. Therefore, knowledge of the mechanisms and supply of these minerals is important. In exceptional cases, a deficiency should be compensated by supplementation; however, supplement over-consumption may be negative to the immune system, and should be avoided. Accordingly, any supplementation should be medically clarified and should only be administered in prescribed concentrations.     

原因不明反复自然流产患者血硒和GPX水平变化

目的 检测原因不明反复自然流产(URSA)患者血硒和谷胱甘肽过氧化物酶(GPX)水平变化,探讨其在反复自然流产发病中的作用.方法 采集URSA患者、正常妊娠妇女和非妊娠妇女(各30例)外周血检测血硒和GPX水平,以及红细胞谷胱甘肽(GSH)水平.结果 URSA患者血硒水平与正常妊娠妇女比较,差异无统计学意义(P>0.05),但比非妊娠妇女明显降低(P<0.01),URSA患者血浆GPX水平均比正常妊娠妇女和非妊娠妇女低(P<0.01),而红细胞GSH水平则明显增高(P<0.01).结论 GPX水平降低可能在URSA发生中扮演了重要角色.     

Role of Nigella sativa and a number of its antioxidant constituents towards azoxymethane-induced genotoxic effects and colon cancer in rats

This study examined the chemopreventive effect of Nigella sativa and some of its antioxidant constituents on a number of colon cancer biomarkers in rats induced with azoxymethane (AOM). Sixty male Sprague-Dawley rats were randomly assigned into ten subgroups: vehicle (1-5) and experimental (6-10). The rats in each group were fed one of the following diets: basal diet, (200 mg/kg) Nigella sativa, (0.2 mg/kg) selenium, (1.2 mg/kg) all-trans-retinol plus (100 mg/kg) DL-alpha-tocopherol and (10 mg/kg) thymoquinone, respectively. Only rats in subgroups 6-10 were injected with AOM (15 mg/kg) once per week for 2 weeks. Both groups were fed their respective diets for 5 weeks. Then they were killed and examined for colonic aberrant crypt foci (ACF). Our result showed that only vitamin supplementation was effective on ACF. Nigella sativa revealed inhibitory effects only on DNA damage (day 34) in the AOM-treated rat group. Alternatively, selenium, thymoquinone and vitamins inhibited the MDA content in the liver. Although the exact mechanisms involved in the protective role of Nigella sativa against the initiation of colon carcinogenesis are not clearly understood, the results suggest that its inhibitory effects might depend on the combined competitive inhibition of various antioxidant constituents of this plant.     

硒对氟致雄性大鼠生殖损害的拮抗作用

目的 :探讨硒对高氟所致雄性大鼠生殖损害的拮抗作用。方法 :1 0 0只雄性Wistar大鼠随机分成对照组、氟 (NaF 1 5 0mg/L)组、氟加低硒 (0 .5mg/L亚硒酸钠 )组、氟 (NaF 1 5 0mg/L)加中硒 (2 .0mg/L亚硒酸钠 )组、氟(NaF 1 5 0mg/L)加高硒 (4 .0mg/L亚硒酸钠 )组 5组 ,通过饮水加氟、加硒的方法染毒 1 0周。观察氟、硒对大鼠体重、睾丸和附睾质量及其脏器系数 ,精子计数、活动率及畸形率 ,睾丸、附睾生化标志酶 ,血清性激素 ,睾丸组织病理切片以及初级精母细胞染色体畸形率的影响。结果 :①右侧睾丸质量对照组为 (1 .80± 0 .2 2 )g ,氟加高硒组为 (1 .6 1±0 .1 1 )g ,2者相比差异有统计学意义 (P <0 .0 5 )。②精子计数 :氟组 (9.2 3× 1 0 7ml-1 )、氟加中硒组 (37.6 7× 1 0 7ml-1 )与对照组 (2 8.6 0× 1 0 7ml-1 )比较 ,差异有统计学意义 (P <0 .0 0 1 ) ;精子畸形率 :氟组 (36 .33% )氟加中硒组 (1 2 .70 % )与对照组 (1 4 .83% )比较 ,差异有统计学意义 (P <0 .0 0 1 ) ;精子活动率 :氟组 (6 2 .0 7%± 6 .5 0 % )氟加中硒组 (6 8.2 1 %± 4 .99% )与对照组 (73.6 7%± 6 .5 1 % )比较 ,差异有统计学意义 (P <0 .0 0 1 )。③LDH :氟组 ((5 79.4 7± 97.1 6 )u/g)、氟加中硒组 ((72 6 .1 3± 1 1     

维生素C对低硒高镉饲养大鼠心肌细胞电生理的影响

目的 进一步阐明微量元素硒镉含量异常是心肌细胞损害的机理。方法 用细胞内微电极技术分别观察了：正常对照、单纯高Cd、高Cd高维生素C、低Se高Cd、低Se高Cd伴高维生素C饲料饲养14w后大鼠心肌细胞电生理的变化。结果 单纯高镉组无变化。低硒并高匐组RP、APA降低,APD50、APD90明显延长;低Se高镉高维生素C组仅RP降低,APA、APD与对照组相比差异无显著性意义。结论 低硒并高可明显改变心肌细胞的电生理特性,维生素C可以对抗低Se并高Cd所致的这种变化。     

维生素C对低硒低铬饲料饲养大鼠肝细胞电生理的影响

目的阐明微量元素Se、Cr含量异常时肝细胞损害的机理。方法用细胞内微电极技术分别观察了：正常对照(两组)、单纯低Se、低Se高维生素C、单纯低cr、低Cr’高维生素C、低Se低Cr、低Se低Cr伴高维生素C饲料饲养14w后大鼠肝细胞电生理的改变。结果单纯低铬组无变化；单纯低硒组RP、APA降低，APD50、APD50延长；低硒并低铬组RP、APA降低，APD50、APD90明显延长；低Se高维生素C组仅RP降低，APA、APD与对照组相比差异无显著性意义。结论低硒并低铬可明显改变肝细胞的电生理特性，维生素C可以对抗低Se并派Cr所致的这种变化。     

The Mo-Se active site of nicotinate dehydrogenase

Nicotinate dehydrogenase (NDH) from Eubacterium barkeri is a molybdoenzyme catalyzing the hydroxylation of nicotinate to 6-hydroxynicotinate. Reactivity of NDH critically depends on the presence of labile (nonselenocysteine) selenium with an as-yet-unidentified form and function. We have determined the crystal structure of NDH and analyzed its active site by multiple wavelengths anomalous dispersion methods. We show that selenium is bound as a terminal MoSe ligand to molybdenum and that it occupies the position of the terminal sulfido ligand in other molybdenum hydroxylases. The role of selenium in catalysis has been assessed by model calculations, which indicate an acceleration of the critical hydride transfer from the substrate to the selenido ligand in the course of substrate hydroxylation when compared with an active site containing a sulfido ligand. The MoO(OH)Se active site of NDH shows a novel type of utilization and reactivity of selenium in nature.     

富硒猕猴桃的降脂作用和对血流变的影响

硒能保护生物膜 ,改善心肌、脑组织损伤后的恢复 [1,2 ] ,我们于 1 998年 1 0月随机选取 8例心脑血管缺血性疾病成人患者 ,使用富硒猕猴桃 ,研究其对脂质代谢和血流变的影响。1　材　料　与　方　法1 .1　材料　　吉首大学富硒猕猴桃课题组培育的鲜果或相当于该果重量的原汁 ,使用北京普力生公司提供的血液流变仪测试各项指标 ,用 2 ,3-二氨基萘荧光法测全血硒含量。1 .2　对象　　选取经确认的高血脂症和心脑血管缺血性疾病患者 8例 ,均为男性 ,年龄最大 65岁 ,最小 35岁。1 .3　方法　　实验前一天空腹测患者的全血硒含量、总胆固醇 (TC)…