碲可抑制动物体内砷的积累

端是一种具有中等毒性的物质。南昌大学化学系陈国树、吴建中等通过对小白鼠进行试验，从中得到了呼在脏器心、肝、肺、肾和脾内的分布、积累规律，发现碲酸钠不易被脏器积累，而亚确酸钠较易积累。碲在脏器内的积累与呼的用量、小鼠喂养时间长短有密切关系，而与小白鼠的性别关系影响不大。亚碎酸钠在脏器内的积累规律是：肾＞肝＞脾＞肺＞心。亚碲酸钠在脏器内的积累规律是：肾＞肝＞肺＞脾＞心。当在同一组小白鼠中同时喂养亚砷酸钠和亚硫酸钠时发现，微量元素税极明显地抑制脏器对砷的积累．同时微量元素端的积累也极显著地降低，两者都…     

富硒肝对大鼠GSH-Px、GSH和游离巯基含量的影响

为观察富硒肝和亚硒酸钠对大鼠抗氧化能力的影响。将6只大鼠分为两组:A组用亚硒酸钠[按Se元素计,6μg/(只.d)]灌胃,B组用富硒肝[按Se元素计,6μg/(只.d)]灌胃。于灌胃第0、4、8、12、16、20天内眦采血,测定血浆和血细胞内液中GSH-Px活力以及GSH、游离巯基的含量。结果表明:①给药20 d后A、B组血浆和血细胞内液GSH-Px活力和GSH含量均明显高于灌胃前(P0.05);②A、B组血浆中游离巯基的含量略有增加,而血细胞内含量则大幅降低(P0.05)。结论:经口给予富硒肝可诱导大鼠产生较多的抗氧化物质,增强大鼠的抗氧化能力。其作用可达同剂量亚硒酸钠水平。     

铅的肾脏毒性与细胞凋亡的关系

为了解铅的肾脏毒性以及与细胞凋亡的关系，建立原位末端标记法检测细胞凋亡。用醋酸铅腹腔注射染毒大鼠，染毒剂量分别为５，１０，２０ｍｇＰｂ＾２＋／ｋｇ体重，１次／天，共染毒３天，对照组腹腔注射醋酸钠２０ｍｇ Ｎａ＾＋／ｋｇ体重，结果，于染毒第二天开始，各染毒组动物体重的增长速率已开始下降，与对照组比较差异有显著性（Ｐ〈０．０５）。肾脏脏器系数，染毒组显著高于对照组（Ｐ〈０．０５）。染毒鼠的肾脏组织凋亡     

氯化稀土对大鼠肝线粒体氧化磷酸化功能的影响

本文论述氯化稀土经口一次染毒对大鼠肝线粒体氧化磷酸化功能的影响。染毒剂量为100、800、1600毫克/公斤。染毒后第4～6天观察到所有染毒组的磷氧比(P/O)均降低,在800和1600毫克/公斤组还见到呼吸控制率(RCR)降低,状态4呼吸率(S_1)升高等氧化磷酸化解偶联现象。结果表明,稀土对大鼠肝线粒体氧化磷酸化解偶联作用表现为迟发反应,且是可逆的,约在一周左右后恢复。     

硒对不同水体致癌因子诱发健康人微核的拮抗作用

采用微核检测技术，研究了亚硒酸钠对启东肝癌高发区不同类型饮用水诱发健康人外周血淋巴细胞微核的拮抗作用。结果表明：（１）各实验水体对细胞的毒性作用，宅沟水〉泯沟水〉自来水〉双蒸水。微核率随着实验水体剂量的增加而升高；（２）１ｍｇ／Ｌ的亚硒酸钠浓度对泯沟水，自来水诱发的微核效应有是显的抑制和／或拮抗作用，呈现明显的剂量－效应关系，提示肝癌高发区饮用水体中确存在与肝癌发病相关的致畸因子，补硒确有防与治原     

亚硒酸钠对大鼠代谢产物影响的核磁共振研究

本文采用核磁共振(^1H NMR)技术研究了在最高耐受摄入量条件下补充亚硒酸钠对大鼠尿液代谢产物的影响。结果表明,在大鼠尿液中甲酸、乙酸、乳酸、丙氨酸、琥珀酸、甘氨酸、马尿酸、苯丙氨酸、色氨酸等代谢物谱峰信号显著增强,而柠檬酸、肌酸、尿素、尿甘素和氧化三甲胺(TAMO)的谱峰信号则显著降低。乳酸、柠檬酸和琥珀酸是体内三羧酸循环的中间产物,其代谢异常是能量代谢紊乱的标志;马尿酸、苯丙氨酸、丙氨酸的代谢异常与肾小球的滤过和回收功能有关;乙酸和甘氨酸的代谢异常则是肝功能损伤的标志,组织切片的结果也证明大鼠的肝和肾已经发生损伤,与^1H NMR的结果相一致。采用HPLC检测到补充亚硒酸钠后尿液中8-OHdG(8-hydroxy1-2′-deoxyguansoine)水平显著升高,证明体内氧化损伤的发生。以上结果表明,在最高耐受摄入量条件下补充亚硒酸钠是不安全的,用NMR方法对阐明硒的毒理学分子基础是有效的。     

核磁共振技术及模式识别对硝酸镥急性毒性的研究

通过分析Wistar大鼠灌胃0.2,2,10和100mg/kg体重硝酸镥[Lu(NO₃)3]48h内尿液的¹HNMR谱,研究了重稀土化合物Lu(NO₃)3在大鼠体内的急性生物效应.以氯化汞、铬酸钠、四氯化碳、盐酸肼和异硫氰酸-α-萘酯为模型药物,利用模式识别技术解析大鼠尿液的¹HNMR谱,对不同剂量Lu(NO₃)3的生物效应进行了分类.结果表明,应用核磁共振和模式识别相结合的方法,可清楚地认识稀土化合物生物效应,低剂量Lu(NO₃)3(0.2,2mg/kg体重)的毒性与肾毒化合物铬酸钠类似,而高剂量Lu(NO₃)3(10,100mg/kg体重)归入肝毒化合物四氯化碳组.该方法也可用于其它金属化合物及中药等药物的毒理学研究.     

亚硒酸钠通过活性氧(ROS)/谷胱甘肽(GSH)/谷胱甘肽过氧化物酶(GPX4)轴诱导非小细胞肺癌A549细胞铁死亡

硒作为人体必需的微量元素,具有抗癌作用,但其抗癌机制尚不明确,因此,通过探讨亚硒酸钠是否可以通过铁死亡途径抑制肺癌A549细胞增殖及其肺癌A549细胞发生铁死亡的具体机制。通过细胞增殖实验(CCK-8实验)及细胞计数实验评价亚硒酸钠对A549细胞增殖的影响,通过流式细胞术分析亚硒酸钠对肺癌A549细胞内线粒体膜电位(MMP)及活性氧(ROS)水平的影响,通过亚铁离子检测试剂盒检测亚硒酸钠作用后肺癌A549细胞内亚铁离子含量变化,MDA检测试剂盒分析亚硒酸钠作用后肺癌A549细胞内脂质氧化产物丙二醛(MDA)含量,分光光度法分析亚硒酸钠对肺癌A549细胞内谷胱甘肽过氧化物酶4(GPX4)及谷胱甘肽(GSH)的表达影响。研究发现：亚硒酸钠能够显著抑制肺癌A549细胞增殖,且亚硒酸钠抑制肺癌A549细胞的半数抑制率(IC₅₀)为10μmol/L;亚硒酸钠能诱导肺癌A549细胞内ROS过度积累并使细胞内谷胱甘肽耗竭;亚硒酸钠作用后,细胞内线粒体膜电位水平显著降低,MDA含量升高而GPX4蛋白表达下调。研究表明,亚硒酸钠能通过诱导肺癌A549细胞内ROS过度积累,引起细胞内...     

灌喂氯化汞大鼠组织中汞结合金属硫蛋白的色谱/质谱联用表征研究

通过测定大鼠脏器组织中汞的总量、金属硫蛋白(MTs)含量及利用尺寸排阻色谱(SEC)与电感耦合等离子体质谱(ICP-MS)联用技术,分析了灌喂HgCl2大鼠脏器组织中汞与MTs的积累量及金属与MTs的结合形态。结果表明,灌喂HgCl2大鼠各脏器中汞的积累量显著高于其相应的对照组,特别是在肾、肝和睾丸中汞的含量较高,表明此3个脏器受汞的危害最大。MTs的含量水平说明当大鼠脏器受汞污染时,肌体中的MTs将被大量诱导产生以对重金属进行解毒。通过SEC-ICP-MS联用技术获得了组织中的金属与MTs的结合形态,其     

Effect of Sodium Fluoride on the Rate of Sperm Deformity in Male Mice

为探讨氟化钠对雄性小鼠精子畸形的影响,选取50只成年雄性小鼠随机分为5组:氟化钠染毒高剂量组(34 mg/kg)、中剂量组(17 mg/kg)、低剂量组(8.5 mg/kg)、环磷酰胺阳性对照组( 50 mg/kg)、生理盐水空白对照组,采用经口灌胃染毒,1次/d,连续5d,于首次染毒后的第35天颈椎脱臼将小鼠处死,取睾丸和附睾称质量,计算脏器系数；同时取附睾制片,观察精子形态,计数小鼠精子畸形率.结果表明,氟化钠染毒各组睾丸、附睾脏器系数与空白对照组比较,差别无统计学意义(P＞0.05),染毒各组精子畸形率普遍高于空白对照组,差别有统计学意义(P＜0.001),且随着染毒剂量的增加精子畸形率也有相应升高,呈现一定的剂量-反应关系(r=0.954,F=20.098,P＜0.05,R2=0.909).提示氟化钠能使雄性小鼠精子畸形率明显升高,具有一定的生殖毒性,能影响小鼠生殖功能,对小鼠生殖功能造成损害.     

Review: Reactive selenium metabolites as targets of toxic metals/metalloids in mammals: a molecular toxicological perspective

Human activities have been contaminating the environment with toxic heavy metal and metalloid compounds. Since the toxicity of one metal or metalloid can be dramatically modulated by the simultaneous ingestion of another, studies addressing the molecular basis of chemical interactions between toxic and essential elements are increasingly important. The intravenous injection of rabbits with selenite and arsenite or with selenite and mercuric mercury resulted in the in vivo formation of the seleno‐bis (S‐glutathionyl) arsinium ion, [(GS)₂AsSe]^?, or a glutathione‐coated mercuric selenide, (GS)₅(HgSe)_core, in blood. The formation of these species (and the formation of a cadmium–selenium species in blood after the exposure of rats to selenite and cadmium) critically involves reactive selenite metabolites, such as GS–Se^? and/or HSe^?, which indicates that these physiologically important metabolites are molecular targets of ingested toxic metals and metalloids. The fate and stability of [(GS)₂AsSe]^? and (GS)₅(HgSe)_core in vivo imply that the chronic exposure of mammals to inorganic arsenic and mercury will cumulatively affect the bioavailability of selenium, which could lead to selenium deficiency. Since selenium deficiency is significantly associated with the etiology of cancer in humans, the GSH‐driven in vivo formation of selenium‐containing metal and metalloid species provides a likely molecular mechanism for the chronic toxicity of environmentally persistent inorganic arsenic, mercury and cadmium. Copyright © 2002 John Wiley & Sons, Ltd.     

钙锌铁硒及B族维生素联合应用对大鼠小肠铅吸收的影响

通过小肠原位闭式灌流方法探讨了某些营养元素及维生素对大鼠小肠铅吸收的影响。体重280g左右Wistar大鼠分两组（各6只），对照组灌流液成分：40mgPb2/L蒸馏水；实验组灌流液成分：40mgPb2＋5g氯化钙＋1g醋酸锌＋5g氯化铁＋2mg亚硒酸钠＋30mgVitaminB1＋35mgVitaminB6＋10mg叶酸／L蒸馏水。灌流小肠长度15cm左右，灌流液20mL，时间20min，流速2mL/min。结果显示，实验组门静脉血铅浓度明显低于对照组（P＜0．01），说明本实验中所涉及各营养素联合应用能减少铅在大鼠小肠的吸收，但各自作用的贡献尚需进一步研究。     

TISSUE SELENIUM LEVELS AND GROWTH RESPONSES OF MICE FED SELENOMETHIONINE,SE-METHYLSELENOCYSTEINE OR SODIUM SELENITE

Abstract

Mice fed diets containing selenomethionine at a level of 20 ppm selenium and raised to 30 ppm selenium at 3 weeks on experiment showed (1) delayed response to selenium toxicity, (2) slow recovery from the toxicity after removal of selenium from the diet and (3) relatively high deposition and retention of tissue selenium. These data suggest that selenomethonine initially becomes incorporated in to the primary structure of proteins and as such is not particularly toxic. However, upon its slow removal from protein, selenomethionine becomes toxic by forming selenium IV compounds through a pathway similar to that followed by methionine.

Mice fed diets containing sodium selenite or Se-methylselenocysteine at the same level of selenium as the selenomethionine diet showed (1) immediate response to selenium toxicity (2) rapid recovery from the toxicity after removal of selenium from the diet and (3) relatively low deposition and relatively rapid depletion of tissue selenium. These data suggest that sodium selenite and Se-methylselenocysteine ultimately follow similar metabolic pathways and do not become part of the primary structure of proteins. A possible metabolic route for Se-methylselenocysteine is that it is oxidized to toxic selenium IV compounds through an oxidative pathway similar to that followed by S-methylcysteine.     

The semi-micro determination of fluorine,chlorine, and nitrogen in organic compounds: The use of cation exchange resins

The organic compounds are fused in a nickel bomb with sodium in the usual way. If no oxygen is present, the nitrogen is determined as cyanide by Deniges' method. After destruction of cyanide with formaldehyde the total chloride and fluoride is determined by passing the solution through a cation exchange column and determining total acidity in the eluate. The chloride in the same or a separate eluate is then determined by treatment with mercuric oxycyanide or by titration with silver nitrate.     

Titrimetric determination of certain mercaptans with mercuric chloride

A procedure is described for the semimicro determination of certain mercaptans, by means of their reaction with mercuric chloride. The acid liberated during the reaction is titrated with standard alkali after addition of sufficient potassium iodide to convert the surplus mercuric chloride into a stable soluble complex. The procedure has been applied to determine 0.12-1 mmole of these compounds; the results are accurate to within 0.5%.     

Qualitative detection of selenium in fortified soil and water samples by a paper chromatographic-carboxyl esterase enzyme inhibition technique.

Thevetia peruviana seed carboxyl esterase was employed as a biosensor for the detection of selenium compounds by an enzyme inhibition technique on paper chromatograms. The selenium compounds (sodium selenite and selenium dioxide) appeared as white spots on a magenta background due to the inhibition of Thevetia peruviana seed carboxyl esterase (substrate 1-naphthyl acetate, coupling reagent Fast blue B salt). The minimum detectable amounts were about 5 microg of sodium selenite and 5 microg of selenium dioxide. Many other animal and plant carboxyl esterases gave no inhibition spot under the same conditions. Soil and water samples were fortified with sodium selenite and selenium dioxide. A procedure for preparing test solutions and conditions for paper chromatography was established.     

Antiedematogenic activity of two thiazolidine derivatives: N-tryptophyl-5-(3,5-di-tert-butyl-4-hydroxybenzylidene) rhodanine (GS26) and N-tryptophyl-5-(3,5-di-tert-butyl-4-hydroxybenzylidene)-2,4-thiazolidinedione (GS28)

The search for new anti-inflammatory drugs has been constant in several research centers. The use of the Bioisostery concept allows the elaboration of new bioactive compounds with different properties through the introduction of substitute groups in one or more positions of a main molecule with known biological activity. Preliminary works accomplished at our laboratory with 2,4-thiazolidinedione isosters demonstrated inhibitory activity on edema formation for N-tryptophyl-5-(3,5-di-tert-butyl-4-hydroxybenzylidene)-2,4-thiazolidinedione (GS28) and N-tryptophyl-5-(3,5-di-tert-butyl-4-hydroxybenzylidene) rhodanine (GS26). We verified the antiedematogenic and ulcerogenic activity of these two compounds in Wistar rats. The carrageenan induced paw edema suffered significant (p<0.05) inhibition (28.36% on average) for GS28 (100 mg/kg; v.o.) during the entire time of the experiment. GS26 (50 and 100 mg/kg; v.o.) significantly inhibited (p<0.05) the paw edema dextran induced (22.1 and 27.8%, for the respective doses) after 180 min. The compounds GS26 and GS28 did not show ulcerogenic activity on gastric mucous. The results suggest antiedematogenic action for both compounds without the appearance of gastric lesions.     

INNA for interelement correlations in rats after mercuric chloride exposure

In an animal model study, we exposed rats to mercuric chloride through drinking water continuously for eight to ten months. A group of these rats were then taken off mercuric chloride water and fed distilled water. A control group of rats was given distilled water. Rat brain, spinal cord, and kidney were analyzed to determine Hg and nine other elements by INAA. Significant imbalances were detected among the groups. Most of the mercury (Hg) was found to be eliminated from the tissues studied within the first thirty days. Implications of the data are discussed in light of observed trace element imbalances in amyotrophic lateral sclerosis and Alzheimer's disease.     

Cyclization of 3-Cyclopent-2-Enyl-4-Hydroxy[1]Benzopyran-2-One

Cyclization of 3-cyclopent-2-enyl-4-hydroxy[1]benzopyran-2-one (1) with cold cone. sulfuric acid gave a mixture of two products, 2 (10%) and 3 (80%). However, on treatment with mercuric chloride 1 furnished the linear product 4 in 60% yield while with mercuric acetate the bicyclic product 8 was obtained in 50% yield. The structures of products are established by chemical correlation.