稀土离子和钙调蛋白对乳酸脱氢酶活性的影响

分别研究了三价稀土离子、稀土离子和钙调蛋白CaM的复合物以及作为稀土离子配体的二乙三胺五乙酸DTPA及其衍生物二乙三胺五乙酸双二甲酰胺 DTPABDMA和二乙三胺五乙酸双异烟肼DTPABIN对乳酸脱氢酶LDH活性的影响。结果表明稀土离子浓度小于3μmol·L-1时对酶活性具有轻微的激活作用离子浓度增大到6μmol·L-1后则开始表现出抑制作用钙调蛋白可以缓解这种抑制作用二乙三胺五乙酸及其衍生物在浓度超过5μmol·L-1 时对酶活性均有抑制这种抑制作用在加入外源的钙调蛋白后也得到缓解。

NMR relaxation studies of GdDTPA in human serum albumin solution

The water relaxation enhancement behavior of GdDTPA in human serum albumin (HSA) solution has been studied. The results indicate that GdDTPA can integrate noncovalently with HSA, mainly in forms of (GdDTPA)HSA and (GdDTPA),HSA, for which the apparent equilibrium constants are 0.05 mM(-1) and 0.02 mM(-2), respectively. (C) 1999 Elsevier Science Ltd. All rights reserved.

La_2CuO_4的制备及其对催化消除NO活性的影响

用四种制备方法：柠檬酸络合爆炸法，聚乙二醇凝胶法，聚丙烯酰胺凝胶法，DTPA络合法合成了La2CuO4.比较了四种方法的特点及其对La2CuO4结构的影响，并对所得La2CuO4在NO-CO反应中的催化活性的影响进行了研究．结果发现聚乙二醇凝胶法和DTPA络合法有利于形成好的晶形，而聚乙二醇凝胶法和聚丙烯酰胺凝胶法对NO-CO反应有较好的活性，这是由于不同制备方法得到的样品中的缺陷的种类和含量不同所致

Influence of intraperitoneal injection of rare earth compounds on the activities of antioxidant enzymes and the level of lipid peroxidation in mice livers

Following intraperitoneal injection of lanthanum and terbium chloride and their complexes of diethyltriaminopentagacetic acid (DTPA) to adult mice with a dose of 0.28 mmol/kg body weight/day for three days. The activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) and the content of lipid end product, malonaldehyde (MDA) in the mice livers have been assayed respectively. The results show that the activity of SOD was increased and the content of MDA was reduced for LaCl3 treated mice and the two targets were not changed for TbCl3, but the activity of GSH-Px was reduced markedly for both LaCl3 and TbCl3 while the above three targets were not changed for La-DTPA and Tb-DTPA complexes.

A NMR investigation on the interaction of lanthanide complexes with phospholipid bilayers

One and two dimentional NMR methods were used to investigate the interactions of lanthanide complexes (Lncit(2) and Ln-DTPA) with phospholipid bilayers, The results showed that in the phospholipid bilayers dispersion containing citrate ligand at pH 7.4, lanthanide ions would initially combine with citrate ligand and form Lncit, complexes which have little effect on the structure of phospholipid bilayers. Ln-DTPA complex does not affect the bilayers structure either. These results provided important experimental data for evaluating scientifically the toxicities of lanthanide ions when they were introduced into the biological body.

EFFECTS OF METAL-IONS ON THE CONFORMATION OF POLAR HEADGROUP OF SPHINGOMYELIN BILAYER

With the wide application of rare earth in agriculture, medicament, especially the application of Gd-DTPA as nuclear magnetic resonance image reagent in clinical practice([1]), the studies on the toxicology in biological body, as well as the study on the use as informative probes instead of divalent calcium ion in biological and biochemical research have attracted intensive concern([2]). Phospholipids bilayers have served as a model of biomembrane in the last two decades. The effects of metal ions on the conformation of polar headgroup of dipalmitoylphosphatidylcholine (DPPC) bilayers have been reported([3]). Sphingomyelin is major component of several biological tissues such as brain and nerve cells and has identical polar headgroup to DPPC. The interaction of metal ions with sphingomyelin bilayer remains nonrevealed. This note presents the results of the study on this aspect.

Study of FT-Raman Spectroscopy on the Effects of Lanthanide Ions and Their Complexes on the Fluidity of Dipalmitoylphosphatidylethanolamine Bilayer

The effects of lanthanide ions and their complexes of citrate and DTPA ligands on the fluidity of dipalmitoylphosphatidylethanolamine (DPPE) bilayers have been studied by FT-Raman spectroscopy. the results show that lanthanide ions of lower concentrationn decrease the fluidity of acyl chains of DPPE bilayers and change the conformation of C C-C backbone from gauche to the trans lanthanide ions of higher concentration, however, increase the fluidity of acyl chains and increase the gauche population of C-C-C backbone. Lanthanide complex of citrate have no effect on the fluidity of acyl chains of DPPE bilayers in the region of experimental concentration, but La-DTPA complex increase slightly the fluidity of acyl chains. the results also indicated that lanthanide ion of lower concentration changed the lattice packing of hydrocarbon chains from hexagonal form to orthorhombic form, but it is still in hexagonal or distorted hexagonal lattice cell in the gel state in the presence of metal ions and lanthanide complexes of higher concentration

M(NTEA)配合物的NMR研究(M=La，Y，Lu和Ca)

近年,水溶性非离子化的稀土配合物由于可用作潜在的NMR造影剂而受到重视,特别是热力学和动力学均稳定的Gd(Hp-DO3A)和Gd(DTPA-BMA)已应用于临床医学诊断。前文报导了新螯合剂—氨三乙氧基乙酸(NTEA)的合成及其La配台物单晶的结构分析。

EFFECT OF LANTHANIDE IONS ON THE PHASE-BEHAVIOR OF DIPALMITOYLPHOSPHATIDYLCHOLINE MULTILAMELLAR LIPOSOMES

The effect of lanthanide ions (Ln(3+)) and their coordination compounds of diethylenetriamine pentaacetic acid (DTPA) on the phase behavior of dipalmitoylphosphatidycholine (DPPC) multilamellar liposomes has been studied by differential scanning calorimet

钆对二棕榈酰磷脂酰胆碱脂质体相变性质的影响

随着稀土在农业、药物等方面的应用日益广泛,特别是钆的二乙三胺五乙酸配合物(Gd-DTPA)已被临床应用于核磁共振成像的造影剂等,因此研究稀土在生物体内的作用机理,已成为当前极感兴趣的课题,虽然有关稀土的宏观毒理学已有不少报道,但是研究稀土对生物膜的影响报道很少,钆对生物膜的作用尚未见报道,稀土离子和钙离子在体内的竞争亦是人们关心的问题,本文采用差示扫描量热(DSC)、激光拉曼技术研究了钆离子及Gd-DTPA等对人工膜二棕榈酰磷脂酰胆碱(DPPC)脂质体相变性质的影响,并观察了Gd~(3+)对人工膜上结合钙的取代作用。

新的水溶性~(13)C NMR弛豫试剂的性质研究

合成了Gd~(3+)与2,3-二羟基-对-二甲苯胺四乙酸(DPTA)的固体配合物,研究了该化合物作为水溶性~(13)NMR弛豫试剂的性质,证明该试剂对增强各种氨基酸(苏氨酸、半胱氨酸、精氨酸、组氨酸、色氨酸和抗坏血酸)季碳原子的谱峰强度是十分有效的。精氨酸的自旋-晶格弛豫时间(T_1)测量表明,Gd-DPTA可使精氨酸分子中季碳T_1缩短200倍以上,效果优于Gd-DTPA。

土法炼锌导致土壤中铅分布特征和形态变化的研究

对贵州省赫章县土法炼锌区土壤中Pb分布特征和形态变化进行了研究.各炼锌点表层土壤中全铅含量71.8～37 247.4mg·kg^-1,远高于贵州省土壤背景值（29.3 mg·kg^-1）.其分布特征表现为：土壤中Pb含量总趋势随着炼锌时间增加而增加,随着距废渣堆的距离增加而降低.剖面中全铅含量分析表明Pb主要累积在土壤表层,但随着冶炼时间增加深层土壤中Pb累积程度也逐渐加大.以CaCl2和DTPA作为提取剂的简化连续提取法对土壤中Pb形态进行分析,结果显示,土壤中CaCl2和DTPA提取态Pb占全量的比例很低,平均值分别为0.3%和5%,但是其绝对含量高达6.4～1 037mg·kg^-1;并随着Pb在土壤中累积时间的加长,CaCl2和DTPA提取态Pb所占比例呈显著降低的趋势,但其绝对含量逐渐增加.

土法炼锌导致Cd对土壤-农作物系统污染的研究

采用现场取样及室内分析方法，研究了贵州省赫章县的土法炼锌活动导致Cd对当地土壤-农作物系统的污染状况及规律。结果表明，炼锌污染土壤Cd含量高达5．3～144．7mg·k^-1，且Cd在土壤中的累积程度随着冶炼时间的增长而加剧。形态分析结果显示，土壤中的CaCl2和DTPA提取态Cd分别占全量的2．47％～16．80％和3．18％～10．11％，随着Cd在土壤中累积时间的加长，CaCl2和DTPA提取态Cd的百分含量均呈显著下降趋势。土壤污染导致农作物体内Cd的明显蓄积，玉米、土豆和大豆三类当地主要农作物可食部分Cd含量分别为1．8、4．8和2．0mg·kg^-1，分别超过国家粮食卫生标准9、24和10倍。相关分析结果显示，CaCl2提取态Cd与农作物中Cd含量没有相关关系，而DTPA提取态Cd和全量Cd与农作物根和茎叶中Cd含量显著正相关。

简化连续提取法评价污染土壤中Zn、Cd的植物有效性

以0．01mol·L^-1 CaCl2和0．005mol·L^-1 1DTPA作为提取剂，用简化的3步连续提取法对贵州省赫章县土法炼锌污染土壤中Zn、Cd的形态进行了分析．结果显示，污染土壤中Zn、Cd主要以残渣态的形式存在，CaCl2提取态和DTPA提取态Zn、CA平均仅占全量的0．63%、3．91％和lO．94％、10．13％．土壤中不同形态Zn、Cd含量与玉米中Zn、CA含量的相关分析结果显示，CaCl2提取态金属与玉米中金属含量投有显著的相关关系，而DTPA提取态、残渣态以及总量Zn、Cd与玉米根、茎叶中Zn、Cd含量显著正相关．这些结果表明CaCl2提取态Zn、Cd对土壤中该元素的植物有效态可能不具重要贡献，而DTPA提取态金属和金属总量在一定程度上能作为评价土壤中元素植物有效性的标准．

几种萃取剂对土壤中重金属生物有效部分的萃取效果

采用6种萃取剂：pH=7的0.01mol/L CaCl2、pH＝7.3的0.005mol/L DTPA+0.1mol/L TEA(三乙醇胺）＋0.01mol/L CaCl2、0.1mol/L NaNO3、0.43mol/L HOAc、pH=7的0.05mol/L EDTA和pH=4.65的0.5mol/L NH4OAc+0.01mol/L EDTA浸取液，对污染土壤中的重金属Cu、Zn、Cd、Pb的进行了萃取，并比较了萃取剂的萃取能力。实验结果表明，HOAc、EDTA以及NH4OAc－EDTA萃取各种重金属的能力远远大于其它几种萃取剂的萃取能力，是比较理想的萃取剂。