硒和镉联合作用对大鼠肝脏TERT mRNA表达的影响

目的研究亚硒酸钠、氯化镉及其联合作用对大鼠肝脏端粒酶逆转录酶(TERT)mRNA表达的影响。方法健康雄性SD大鼠随机分组,每组动物5只。对照组,硒组(2.5、5和10μmol/kg Na2SeO3)、镉组(5、10和20μmol/kgCdCl2)以及硒镉联合作用组。染毒48h后取出肝脏,用RT-PCR方法检测TERT基因的表达。结果与对照组比较,3个剂量硒组的TERT mRNA虽有增高,但P>0.05,而3个剂量的镉组TERT mRNA表达均增多(P<0.01);在硒镉联合作用组中,虽然3个剂量的硒均可分别使3个剂量的镉诱导的大鼠肝脏TERT mRNA表达下降,但仅在2.5μmol/kg Na2SeO3 5μmol/kg CdCl2组、2.5μmol/kg Na2SeO3 10μmol/kg CdCl2组和5μmol/kg Na2SeO3 10μmol/kg CdCl2组,与相应剂量的镉组比较,TERT mRNA水平降低,差异具有显著性。10μmol/kg Na2SeO3 5、10和20μmol/kg CdCl2联合作用组与对照组相比,TERT mRNA水平均升高,与对应镉组相比,差异无显著性。结论镉在5~20μmol/kg的剂量条件下可以诱导大鼠肝脏高表达TERT mRNA,而一定剂量的硒对一定剂量镉引起的TERT mRNA的表达具有一定的拮抗作用。     

硒盐预防原发性肝癌前瞻观察六年

本文报道江苏省启东肝癌高发人群吃硒盐预防原发性肝癌前瞻研究。通过观察六年,吃硒盐的居民血硒明显升高。肝癌发病率逐年下降,1984年52.84/10万,1990年降为34.49/10万。对照组居民肝癌发病率仍维持较高水平,提示补硒可以预防肝癌。1987年启东病毒性肝炎暴发流行,但硒盐乡居民肝炎发病率明显较对照组低(P<0.01)。可见补硒既可防癌,又可防肝炎。硒盐生产工艺简单,经济方便,可在低硒或缺硒地区推广应用。     

亚硒酸钠对亚硝基胍诱发大鼠腺胃胃癌的影响

本文报告亚硒酸钠对N-甲基-N’-硝基-N-亚硝基胍(MNNG)诱发大鼠腺胃胃癌的影响。结果表明大鼠饮水每日添加10mg/kg的亚硒酸钠可以抑制MNNG诱发腺胃胃癌、异型增生及前胃病变的发生,并促进癌周纤维组织增生及包裹形成。在大鼠MNNG诱癌实验中,硒作为化学预防剂的每日添加量应低于每只20mg/kg,而饮水浓度不宜超过4mg/L。     

LONG TERM SUPPLEMENTATION OF SE-ENRICHED MALT FOR THE HIGH RISK POPULATION OF LUNG CANCER: INHIBITION OF ULTRAVIOLET LIGHT AND BENZOaPYRENE INDUCED UNSCHEDULED AND SYNTHESIS OF PERIPHERAL LYMPHOCYTES

Se malt cakes containing 300μg selenium were taken up daily to men from high risk area in lung cancer and the influences of Ultraviolet (UV) and Benaopyrene (BαP) induced unscheduled DNA synthesis (UDS) were determined. The Se levels in serum, hair and activity of GSH-px were increased by 89%, 67% and 178%, respectively, after Se-supplementation for half year. In the UV treatment, the ratio of UDS was decreased from the mean values of 2. 47 in the control to 1. 61 (P<0. 05) in the Se-group, In the BaP treatment, furthermore, the elevated Se levels of 78% in serum and 83% in the hair accompanied with 56% high in activity of GSH-px were followed by the Se intake for one year, while the mean value of UDS was reduced from 2. 21 in the control to 1. 47(P< 0. 05) in the group of selenium tested. The blocking effects of UV irradiation and BaP treatment induced UDS of peripheral lymphocytes were showed in the Se-supplementation.     

硒缺乏对大鼠胰岛内分泌细胞功能的影响

应用食饵性低硒方法，研究大鼠在硒缺乏状态下胰岛内分泌细胞合成和分泌多肽类激素功能的变化，结果表明硒缺乏鼠血清胰岛素、Ｃ肽及生长抑素水平下降；胰岛Ｃ肽、胰岛素及生长抑素分泌贮备减少，并伴有胰腺ＧＳＨ－Ｐｘ活力减低，ＬＰＯ含量升高。     

银屑病患者血硒含量与GSH-Px活力的研究

为探讨银屑病发病机理，随机取正常人和患者各１０例，用二氨基萘荧光法测定血硒含量和二巯基二硝基苯甲酸反应显示谷胱甘肽过氧化物酶（ＧＳＨ－Ｐｘ）活力。结果表明：患者组血硒含量比正常组低，由于硒含量降低，导致ＧＳＨ－Ｐｘ活力明显下降。提示缺硒可能是诱发银屑病发病的主要因素之一。     

Selenium status of industrial worker

The purpose of this study was to assess the selenium status of a well-defined industrially employed population: eighty-six oil refinery workers. Plasma selenium levels and erythrocyte GSH-Px activities were significantly lower in this industrial group (86 subjects) than in non-industrial group (174 subjects). In order to evaluate whether these lower values were responsive to supplementation, ten subjects from the industrial group were further studied for 12 weeks. Five of these subjects consumed a selenium supplement, 50 μg Se as sodium selenite, once a day for eight weeks (weeks 2 to 10 of study). Diet histories revealed that these 10 workers consumed an average of 217±73 μg Se/day indicating that they were consuming selenium levels above the recommendations of the Food and Nutrition Board of the NRC. The supplemented group had significantly higher whole blood selenium levels and GSH-Px activity than the non-supplemented group and this difference was due to a drop in the levels found in the non-supplemented group at weeks 8 and 10. These data suggest that selenium supplementation prevented the decreases in blood selenium levels and GSH-Px activity experienced by the non-supplemented subjects. Also, there was a positive correlation between blood selenium levels and GSH-Px (r=0.45, p<0.001). Thus, these oil refinery workers maintained GSH-Px activity only when consuming a selenium supplement suggesting that these workers may have a higher selenium need than any previously studied populations.     

硒和B-27添加剂在神经干细胞存活与分化中的作用

目的 观察微量元素硒和神经细胞培养添加剂B-27对神经干细胞存活与分化的影响。方法 采用新生Wistar大鼠神经干细胞体外分离培养技术,应用盖玻片培养法和免疫细胞化学法来观察在无血清培养液中加入添加剂B-27和不含B-27时,硒对神经干细胞存活以及神经元分化标记蛋白β-微管蛋白、星形胶质细胞标记蛋白抗胶质细胞醋酸纤维蛋白（GFAP）和少突胶质细胞标记蛋白抗环核苷酸磷酸二酯酶（CNP酶）表达的影响。结果 在培养液中加入B-27添加剂同时加入硒时,神经干细胞能够存活并且分化成熟良好。在不含B-27添加剂同时也不含硒的培养液中神经干细胞不能够存活。在不含B-27添加剂而含有硒时,神经干细胞则能够存活并且能分化成神经元、星形胶质细胞和少突胶质细胞,各种细胞的形态典型。显微镜下计数发现神经干细胞在含硒的培养液中向神经胶质细胞方向分化比例较高。其中神经元分化β-微管蛋白阳性细胞每高倍视野为11．2个。胶质细胞分化方向GFAP阳性和CNP酶阳性细胞计数平均每高倍视野分别为16．1个和9．3个。结论 硒对于神经干细胞体外存活和分化是必需的营养成分。在不含B-27,但有硒存在时,神经干细胞能够存活并分化成熟。     

Changes in distribution of mercury and selenium in soluble fractions of rabbit tissues after simultaneous administration

The existing states of mercury and selenium in the blood and in soluble fractions of perfused rabbit liver and kidney were studied by gel filtration on Sephadex G-200 1 hr or 24 hr after intravenous injection of mercuric chloride and/or sodium selenite. Both mercury and selenium in the plasma and stroma-free hemolysate were found to exist in the high-molecular weight fraction following simultaneous injection of mercuric chloride and sodium selenite. Patterns in gel filtration of the plasma and the stroma-free hemolysate did not show any significant change between 1 hr and 24 hr after the administration. A similar tendency as described above was obtained with the liver-soluble fraction at 24 hr after injection of mercuric chloride and sodium selenite. A possible role of the high-molecular weight complex, which is quickly formed by the interaction of mercury and selenium in blood stream, in decreasing the acute renal toxicity of inorganic mercury is discussed.     

Species differences in contaminants in fish on and adjacent to the Oak Ridge Reservation, Tennessee

Risks to humans and other organisms from consuming fish have become a national concern in the USA. In this paper, we examine the concentrations of 137Cs, arsenic, beryllium, cadmium, lead, mercury, and selenium in three species of fish from two river reaches adjacent to the US Department of Energy's Oak Ridge Reservation in Tennessee. We were interested in whether there were species and locational differences in radiocesium and metal concentrations and whether concentrations were sufficiently high to pose a potential health risk to humans or other receptors. Striped bass (Morone saxatilis) were significantly larger than white bass (M. chrysops), and crappie (Pomoxis spp.) were the smallest fish. Lead was significantly lower in striped bass, mercury was significantly higher in striped bass, and selenium was significantly higher in white bass compared to the other species. There were no other species differences in contaminants. White bass, the only species that was sufficiently abundant for a comparison, had significantly higher concentrations of cadmium, lead, and selenium in fillets from the Clinch River and significantly higher concentrations of mercury in fillets from Poplar Creek. The low concentrations of most contaminants in fish from the Clinch River do not appear to present a risk to humans or other consumers, although mercury concentrations in striped bass ranged as high as 0.79 ppm, well above the 0.5-ppm action level for human consumption of some US states.