酒石酸及其盐抑制泌尿系结石的化学基础

本文探讨了酒石酸及其盐对泌尿系结石形成、抑制和治疗的化学基础，重点讨论了其与钙离子的螯合，诱导二水草酸钙和三水草酸钙形成、减少晶体滞留，影响CaOxa晶体的晶面与形貌，抑制尿石矿物的成核、生长和聚集，调节新陈代谢、减小尿石形成的几率，并讨论了抗衡阳离子对其抑制能力的影响。     

不同介质凝胶体系中草酸钙结晶的研究

研究了五种不同介质（水、氯化钠、合成尿、正常人尿液和尿石患者尿液）的凝胶体系中草酸钙（CaC2O4）晶体的生长,及各种体系中防石药物柠檬酸钾（K3cit）对CaC2O4生长的影响.没有加K3cit时,CaC2O4晶体以一水草酸钙（calcium oxalate monohydrate, COM）为主要物相,但在氯化钠和合成尿的凝胶体系中同时出现了二水草酸钙（calcium oxalate dihydrate, COD）和三水草酸钙（calcium oxalate trihydrate, COT）,肾结石患者尿液中出现COD,而正常人尿液中没有COD和COT生成.加入K3cit后,水、氯化钠和合成尿介质的凝胶体系中,COT的含量显著增加,患者尿液中产生大量COD,而正常人尿液中出现了少量的COD和极个别的COT.COT的增加与低温、体系中高的离子强度及金属离子等因素有关.K3cit具有诱导COD和COT的生成、减小COM晶体比表面积的作用,从而有利于防治草酸钙结石的形成.     

植物药抑制泌尿系结石形成的化学基础

植物药治疗泌尿系结石具有独特的疗效.本文综述了国内外植物药(泽泻,Phyllanthus niruri,Zeamays,Agropyron repens和Herniaria hirsute等)在体外模拟实验和动物实验中对泌尿系结石形成的影响,植物药抑制泌尿系结石形成的机制和化学基础是:植物药与钙离子发生配位,降低尿石盐的过饱和度;抑制一水草酸钙生长,诱导二水草酸钙形成;抑制晶体生长和聚集;可以保护尿路粘膜,防止晶体在肾上皮细胞上发生粘附;改变尿石形成促进剂和抑制剂的排泄量.     

聚合物与草酸钙相互作用的研究进展及其对预防尿路结石的意义

聚合物对泌尿系结石的形成具有抑制和促进双重作用。本文综述了聚合物对尿石矿物草酸钙成核、生长、聚集及其与尿路细胞膜黏附影响的研究进展,讨论了聚合物影响草酸钙晶面和形貌的机理,指出了该领域所面临的问题和将来的发展方向。     

粘液素对草酸钙晶体生长的影响

泌尿系结石是一种常见疾病。在70％以上的结石中,草酸钙(CaOxa)单独或和其它钙盐共同为主要成分。一般认为正常人不形成尿石是其尿液中存在的抑制剂抑制了CaOxa晶体的成核、生长、聚集或固相转化。     

海藻硫酸多糖抑制草酸钙结石形成的化学模拟

用体外模拟方法研究了从海藻异枝麒麟菜中提取的硫酸多糖(ESPS)对尿结石患者尿液中草酸钙晶体生长的影响. ESPS不但诱导与尿路细胞膜粘附力较弱的二水草酸钙晶体形成, 而且抑制一水草酸钙的生长和聚集, 归因于一水草酸钙的富钙(101)晶面与聚阴离子ESPS之间的静电相互作用. 上述结果表明, ESPS是一种抑制草酸钙结石的潜在绿色药物.     

沙苑子提取液对不同体系中草酸钙晶体生长影响的研究

通过与水、氯化钠、正常人尿液体系的比较,重点研究了结石患者尿液体系中加入中药沙苑子提取液对草酸钙晶体生长的的影响,利用SEM,FTIR和XRD等测试手段对所得晶体进行表征。结果发现:在结石患者尿液体系中形成的草酸钙晶体为一水草酸钙(COM)晶体,而在这4种体系中加入沙苑子提取液后,只形成二水草酸钙(COD)晶体,表明沙苑子提取液能抑制COM晶体生长,并且随着沙苑子提取液浓度增大,抑制作用增强。沙苑子抑制草酸钙晶体生长的可能机理进行了探讨。     

服用柠檬酸钾前后草酸钙结石患者的尿微晶和尿液性质变化

采用透射电子显微镜(TEM)、扫描电子显微镜(SEM)、X射线衍射(XRD)、傅立叶变换红外光谱(FTIR)和ζ电位分析仪研究了草酸钙(CaOxa)结石患者在服用柠檬酸钾(K3cit)前后尿液中微晶的性质变化,这些性质包括:尿微晶的形貌、尺寸、聚集状态、质量、种类和ζ电位,并研究了服药前后尿液的稳定性差异和pH值变化。服用K3cit前,结石患者的尿微晶棱角尖锐,聚集明显,尺寸从几十纳米到几百微米不等,主要为一水草酸钙(COM)、尿酸等;而服用K3cit一周后,部分尿微晶的形状变得圆钝,聚集现象明显减少,平均粒径减小,部分尿微晶的表面出现凹陷,二水草酸钙(COD)和尿酸盐的百分含量增加,尿微晶的数量和种类减少,尿液pH值上升,ζ电位绝对值增加,自相关时间增加。从患者服用K3cit后引起尿pH值增加、尿液中排泄的柠檬酸和Tamm-Horsfall蛋白浓度增加、柠檬酸与Ca2+离子配位等角度,讨论了K3cit抑制CaOxa结石形成的机制。     

尿液中的纳米微晶及其与尿石形成的关系

尿石症是一种世界范围的常见病和多发病,其主要的矿物成分为草酸钙(CaOxa)等[1-2]。但至今为止,尿石症形成过程中的许多化学及物理问题尚不清楚:尿液中的微晶是怎样生长和聚集?随后又是怎样黏附到尿路细胞膜上而形成结石?正常人与尿石患者尿液中微晶的数量和尺寸等存在什么样的     

不同模拟体系中草酸钙结晶的比较研究

泌尿系结石是一种世界范围内的常见病及多发病 ,如深圳市的尿结石患病率高达 4.87%[1] ,其发病率呈上升趋势 .泌尿系结石在手术后复发率高 ,尤其是对结石的预防 ,目前尚无十分理想的方法 ,至今其形成机制未完全阐明 ,80 %以上的尿结石患者病因不清 [2 ] .草酸钙 (Ca C2 O4 )是泌尿系结石的主要成分 .体内 Ca C2 O4 结石的形成与热力学 (过饱和度 )和动力学 (成核、生长和聚集 )因素相关 .虽然在尿液中发现有二水草酸钙 (COD)晶体 ,但是热力学稳定的一水草酸钙 (COM)是尿石中最普遍的晶型[3 ] .在大多数的 Ca C2 O4 结石中 ,COM的发…     

Effect of Concentration of Structurally-Different Carboxylic Acids on Growth and Aggregation of Calcium Oxalate in Gel Systems

The effect of concentration of structurally-different carboxylic acids such as ethylene diamine tetraacetic acid （H4edta）, citric acid （H3cit）, tartaric acid （H2tart）, and acetic acid （HOAc） on growth and aggregation of calcium oxalate （CaOxa） in gel systems was comparatively investigated. H2tart and H3cit could change the morphology of cal- cium oxalate monohydrate （COM） and induce the formation of calcium oxalate dihydrate （COD）. H4edta could induce the formation of COD at a lower concentration of 0.33 mmol/L and have the strongest ability to inhibit aggregation of COM. HOAc inhibited COM aggregation only at a higher concentration than 500 mmol/L. With increasing the number of carboxylic groups in an acid or increasing the concentration of carboxylic acid, the capacity of this acid to induce COD formation and to inhibit growth and aggregation of COM crystals increased. That is, this capacity followed the order： H4edta〉H3cit〉H2tart〉 〉HOAc. The result in this work suggested that the presence of H3cit and H2tart in urine played a role in the natural defense against stone formation.     

二水草酸钙的形成及其对尿路结石的防治

二水草酸钙(COD)是泌尿系结石的主要成分之一,其成核、生长和聚集过程与尿石的形成密切相关。本文结合我们近年来的工作,综述了生物膜及其模拟膜对COD的调控作用,尿大分子、焦磷酸盐、多磷酸盐、柠檬酸、酒石酸及表面活性剂等尿小分子的诱导作用,过饱和度、化学计量条件、pH值、离子强度、温度等体系参数对COD形成的影响;讨论了COD的形貌、晶面电荷及其与细胞膜粘附的研究进展。从临床上预防和治疗草酸钙结石的角度,综述了有利于COD形成的因素。     

Effects of temperature and sodium carboxylate additives on mineralization of calcium oxalate in silica gel systems

Urolithiasis remains a major medical problem in China, especially in Guangdong Province in the southest of China[1]. A survey in Shenzhen city, the most southern city in China, showed the incidence of renal calculus was 4.87%, being 6.12% in the males and 4.07% in the females[2]. The prevalence of renal calculus has been more as the age advances and in the male population and so was in the less-educated population. The recurrence rate is more than 80%, with a moderate improvement by conventi…     

Inhibition of the crystal growth and aggregation of calcium oxalate by elemental selenium nanoparticles

Chemical modulation of calcium oxalate (CaC₂O₄) crystals morphologies by elemental selenium nanoparticles (nanoSe⁰) was investigated with scanning electron microscopy (SEM), energy-dispersive X-ray analysis (EDX), Fourier transform infrared spectrometry (FTIR), and X-ray diffraction (XRD) analysis. The coordination between nanoSe⁰ and C₂O₄²⁻ had great effect on the formation of CaC₂O₄ crystals. NanoSe⁰ inhibited the growth of calcium oxalate monohydrate (COM) crystals, prevented the aggregation of COM crystals and induced the formation of the spherical calcium oxalate dihydrate (COD) crystals containing selenium, which are the thermodynamically less stable phase and has a weaker affinity to the cell membranes than COM crystals. The inhibition of the crystal growth and aggregation of CaC₂O₄ crystals by nanoSe⁰ displayed concentration effects.     

Zur Wirkung von Citronensäure auf die Hydratation von Tricalciumsilicat (Ca3SiO5)

The Influence of Citric Acid on the Hydration of Tricalcium Silicate (Ca₃SiO₅) The influence of citric acid on the hydration of tricalcium silicate was investigated. The strong retarding effect of this acid is discussed on the basis of Ca(OH)₂ solubility, the formation of a protective layer at the surface of Ca₃SiO₅ and an inhibition of the crystallization of calcium hydroxide.     

The enthalpies of interactions of Ca2+(aq) and C2O 4 2− (aq) ions in complexon solutions: Competition between complexation and precipitation

The thermal effects of mixing of aqueous calcium chloride with sodium citrate and ethylenedi-aminetetraacetate in the absence and presence of sodium oxalate have been measured at 25°C. The thermal effects of dilution of aqueous calcium chloride solutions were determined. The thermal effects of calcium oxalate precipitation and formation of calcium complexes with citrate and ethylenediaminetetraacetate ions were calculated. The 1% solution of sodium citrate inhibited the formation of CaC₂O₄ (s); in a 1% solution of sodium ethylenediaminetetraacetate with [Ca²⁺][C₂O ₄ ^2? ] > 10^?5, the endothermal formation of the [CaEdta]^2? complex quickly changed to exothermal precipitation. The 3 and 5% solutions of complexons showed a pronounced inhibiting effect on the formation of urinary stones even when the concentration of calcium and oxalate ions in solution exceeded the product of solubility of CaC₂O₄ by four and more orders of magnitude.     

Solid and solution chemistry of protonated and deprotonated mononuclear molybdenum(VI) citrates

Mononuclear molybdenum(VI) citrates with variable degrees of protonation, (NH₄)₂[MoO₂(H₂cit)₂]·H₂O (1), (NH₄)₃[MoO₂(H₂cit)(Hcit)]·H₂O (2) and (NH₄)₅[MoO₂(Hcit)(cit)]·2.5H₂O (3) (H₄cit = citric acid), have been well characterized, where the citrate ligands in 1–3 coordinate bidentate with Mo, while the free carboxylates form very strong hydrogen bonds with α-alkoxy and β-carboxylic acid groups. The chelation of α-alkoxy and α-carboxy groups in citrate are compared with that of FeMo-cofactor in NifV^– Klebsiella pneumoniae nitrogenase. Solution ¹³C NMR spectra show that 1–3 dissociated partly in D₂O. The equilibria are calculated based on ¹H NMR spectra in solution.     

Study of the Ternary Complex Formation Between Vanadium(III), Dipicolinic Acid and Small Blood Serum Bioligands

Ternary complex formation reactions were studied between vanadium(III), dipicolinic acid and small molecular weight blood serum components: lactic, oxalic, citric and ortophosphoric acids. The electromotive force measurement permitted us to determine the chemical speciation of the complexes formed. In the vanadium(III)–dipicolinic acid–lactic acid system the complexes detected were: V(dipic)(lac), V(dipic)(lac)(OH)⁻ and V(dipic)(lac)(OH)₂^2-(\mathrm{OH})_{2}^{2-}. In the vanadium(III)–dipicolinic acid–oxalic acid system the observed complexes were: V(dipic)(ox)⁻, V(dipic)(ox)(Hox)²⁻ and V(dipic)(ox)₂^3-(\mathrm{ox})_{2}^{3-}. In the vanadium(III)–dipicolinic acid–citric acid system the complexes V(dipic)(Hcit)⁻, V(dipic)(cit)²⁻, V(dipic)(cit)(OH)³⁻, V(dipic)(cit)(OH)₂^4-(\mathrm{OH})_{2}^{4-} and V(dipic)(cit)(OH)₃^5-(\mathrm{OH})_{3}^{5-} were detected. Finally in the vanadium(III)–dipicolinic acid–phosphoric acid system the complexes V(dipic)(H₂PO₄) and V(dipic)(HPO₄)⁻ were observed. The UV-vis spectra allowed us to perform a qualitative characterization of the complexes formed in aqueous solution.