Simulation of calcium oxalate stone in vitro

Urolithiasis constitutes a serious health problem that affects a significant section of mankind. Between 3% and 14% of the population, depending on the geographical region, suffer from this illness[1]. For example, the incidence of urolithiasis in Florida in the United States of America was 15.7 in 100000 people and increased to 20.8 in 1996. Urolithiasis remains a major medical prob-lem in China, especially in Guangdong Province. A survey in 1997 in Shenzhen City, the most southern city i…     

玉米须提取液对尿液中草酸钙晶体形成的影响

本文采用X射线衍射(XRD)、红外光谱(FTIR)、扫描电子显微镜(SEM)等方法分析了玉米须提取液对正常人尿液中草酸钙晶体形成的影响,通过电导率法研究了草酸钙晶体生长的动力学过程,以及从生物矿化的角度对玉米须提取液影响尿液中草酸钙晶体的可能机理进行了探讨。由于玉米须提取液中有机酸或多糖的羟基、羰基等通过配位作用与Ca²⁺结合形成可溶性配位化合物,减少了Ca²⁺与Oxa^2-的结合能力,从而抑制了CaOxa的成核和生长。同时,可能由于玉米须提取液中有效成分与二水草酸钙(COD)的吸附点键合,增强了COD晶体在溶液中的热力学稳定性,进而抑制了COD晶体向热力学更稳定态的一水草酸钙(COM)晶体转变。结果显示,这种抑制作用随玉米须浓度增大而增大,且COD晶体尺寸随着玉米须浓度的增大而减小。玉米须抑制COD晶体向COM晶体转变的作用为开发预防和治疗尿结石的药物提供了启示。     

过饱和度、反应物化学计量比及离子强度对草酸钙晶体生长的影响

肾结石是一种普遍的疾病,全球的发病率约为10%,且其复发率高。2003年欧洲的一项统计表明,尿石患者第一次复发率为40%[1]。草酸钙(CaOxa)是肾结石的主要成分,其体外模拟引起了人们广泛的关注[2,3]。然而,普通溶液体系的模拟环境不能充分反映尿石的形成环境,用类似细胞膜的有序分     

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。     

Biogenic synthesis of calcium oxalate crystal by reaction of calcium ions with spinach lixivium

In this paper, we report a biogenic synthesis protocol for preparation of calcium oxalate (CaC₂O₄, CaOx) crystal at room temperature by a simple protein-mediated reaction of aqueous Ca²⁺ ions with the C₂O₄²⁻ ions spontaneously released from spinach. The aggregation of calcium oxalate monohydrate (COM) and calcium oxalate dihydrate (COD) with a rod-like morphology was mainly formed in the spinach root lixivium, and the proportion of COM crystal in the aggregation increased with the concentration of Ca²⁺ ions increasing, however, spindle-shaped crystal was mainly obtained in the spinach leaf lixivium and the content of COM in the product was higher than that obtained in the root lixivium with the similar concentration of Ca²⁺ ions. COM phase disappeared and only COD crystal with morphology of tetragonal bipyramidal prisms presented in the product when the leaf lixivium was replaced by the leaf broth. The biomolecules such as proteins with molecular weight of 31 kDa liberated from the spinach root are negative-charged, which played important roles for the control of CaOx crystal growth in the root lixivium corresponding to the changes of protein secondary structures after reaction with Ca²⁺ ions. This research was potentially important for unraveling the biomineralization mechanism of CaOx crystal.     

Morphological control of calcium oxalate particles in the presence of poly-(styrene-alt-maleic acid)

Calcium oxalate (CaOx) particles exhibiting different shapes and phase structures were fabricated by a simple precipitation reaction of sodium oxalate with calcium chloride in the absence and presence of poly-(styrene-alt-maleic acid) (PSMA) as a crystal modifier at room temperature. The as-obtained products were characterized with scanning electron microscopy (SEM) and X-ray diffraction (XRD). The effects of reaction conditions including pH, [Ca²⁺]/[C₂O₄²⁻] ratio and concentration of PSMA and CaC₂O₄ on the crystal forms and morphologies of the as-obtained calcium oxalate were investigated. The results show that various crystal morphologies of calcium oxalate, such as parallelograms, plates, spheres, bipyramids etc. can be obtained depending on the experimental conditions. Higher polymer concentration favors formation of the metastable calcium oxalate dihydrate (COD) crystals. Lower pH is beneficial to the formation of plate-like CaOx crystals. Especially, the monodispersed parallelogram-like CaOx crystals can be produced by PSMA as an additive at pH 2. PSMA may act as a good inhibitor for urolithiasis since it induces the formation of COD and reduces the particle size of CaOx. This research may provide new insight into the morphological control of CaOx particles and the prevention of urolithiasis.     

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.     

二水草酸钙的热力学转化及海藻多糖的稳定作用

草酸钙结石的形成与尿液中草酸钙的存在形式密切相关，一水草酸钙(COM)促进尿石症形成，而二水草酸钙(COD)易随尿液排出体外。本文采用体外模拟方法，比较研究了COD晶体在水溶液、正常人尿液和结石患者尿液3个不同体系中的稳定性及海藻龙须菜多糖(SPS)对COD的稳定作用。在水溶液和患者尿液中，不但COD转化率高，而且得到的转化产物COM晶体聚集程度大；而在正常人尿液中，COD转化率低，转化产物聚集程度较小。COD在不同体系中转化的速度依次为：水溶液＞患者尿液＞正常人尿液。从海藻龙须菜中提取的硫酸多糖可以稳定COD的存在并减小COM的聚集，这有利于阻止草酸钙结石的形成，因此，海藻龙须菜多糖有可能用于防止草酸钙结石形成。     

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…     

LB膜诱导下草酸钙晶体的生物矿化研究

草酸钙（CaC２O４）结石是生物体内异常矿化形成的产物，是泌尿系结石的主要组成部分犤１犦。它形成于泌尿系统中尿路表皮细胞上犤２犦。磷脂的Langmuir－Blodgett（LB）膜是生物细胞膜的简化模拟体系犤３犦。用磷脂LB膜作为模板来研究CaC２O４晶体的形成过程，比在水溶液中更能接近CaC２O４结石在生物体内细胞膜表面形成的真实情况，将有助于对尿路结石的形成及防治的研究犤４犦。尿大分子硫酸软骨素A（C４S）存在于尿液中，但不存在于CaC２O４结石中。在结石病人尿液中C４S的含量明显低于正常人尿液中的含量，因此推测其在体内…     

The role of vinyl sulfonic acid homopolymer in calcium oxalate crystallization

In this study, the effect of water soluble homopolymer of vinylsulfonic acid on spontaneous crystallization of calcium oxalate (CaOx) was investigated. CaOx crystals exhibiting different shapes and phase structures were produced in the presence of polymer. While the crystal growth of calcium oxalate was inhibited by homopolymer, the morphology of calcium oxalate transformed from monohydrate to dihydrate. Inhibition of calcium oxalate crystallization was provided by adsorption of homopolymer onto the active growth sites of crystals on account of the charge and hydrophilic effects. Polyelectrolyte effects were interpreted in terms of the adsorption of inhibitors onto the active growth sites on the crystal surface.     

Induction of Ring‐Shaped Calcium Oxalate Patterns by Boundaries between Liquid Expanded Phase and Liquid Condensed Phase in Langmuir‐Blodgett Film

The formation of calcium oxalate kidney stones was related to injuries of renal epithelial membranes. The liquid condensed (LC) domains in Langmuir‐Blodgett (LB) film of dipalmitoylphosphatidylcholine (DPPC) were used as a model system to induce crystal growth of urinary mineral calcium oxalate monohydrate (COM). The circular defective boundaries between the LC and liquid expanded (LE) phases of the DPPC monolayer could provide much more nucleating sites for crystallization of COM crystals. It induced ring‐shaped or solid circular patterns of COM crystals on hydrophobic quartz substrates depending on the crystallization time.     

Dissolved urate salts out calcium oxalate in undiluted human urine in vitro: implications for calcium oxalate stone genesis

Hyperuricosuria has long been documented as a predisposing factor to calcium oxalate (CaOx) stone pathogenesis. However, its mechanism is still without sound scientific foundation. Previously, we showed that hyperuricosuria, simulated by the addition of dissolved sodium urate, promotes the crystallization of CaOx. In the present study, we demonstrate that the urate's effect on the crystallization is attributable to its salting out CaOx from solution. Furthermore, analysis of urines revealed that their metastable limit decreased with increases in the product of the prevailing concentrations of calcium and urate: this has implications for CaOx stone genesis. We also outline anti-salting out strategies for future research for the prevention and/or treatment of CaOx calculi.     

海藻异枝麒麟菜多糖抑制尿石盐草酸钙晶体生长的研究

采用扫描电子显微镜(SEM)、 红外光谱(FTIR)和X射线衍射(XRD)方法研究了从海藻异枝麒麟菜中提取的硫酸多糖(ESPS)对草酸钙(CaOxa)晶体生长的影响. 结果表明, 添加ESPS能抑制一水草酸钙(COM)的生长, 同时诱导二水草酸钙(COD)晶体的形成. 随着ESPS的质量浓度从0增加到0.03和0.50 mg/mL, COD的质量分数从0分别增加到10%和55%; COM的(1 01)晶面加强, (020)晶面减弱直至消失, 并从三维晶体转变为棱角圆顿的四角形片状晶体; COM和COD的尺寸均明显变小. 这些结果表明, ESPS是抑制CaOxa结石形成的一种潜在药物.     

凝胶体系中不同结构羧酸盐对草酸钙生物矿化的影响

采用双扩散法研究了凝胶体系中四元羧酸盐(Na2EDTA)、三元羧酸盐柠檬酸钠（Na3cit）、二元羧酸盐酒石酸钠（Na2tart）和一元羧酸盐醋酸钠（NaAc）对草酸钙（CaOx）结晶的影响.抑制一水草酸钙（COM）聚集的能力为:Na2EDTA >Na3cit >Na2tart >NaAc；诱导二水草酸钙（COD）的能力为：Na3cit >Na2tart >Na2EDTA >NaAc.羧酸的抗衡阳离子影响CaOx的结晶. H3cit、Na3cit和K3cit抑制COM聚集和诱导COD形成的能力均为:K3cit-Na3cit >H3cit.无论是诱导COD生成，还是抑制COM聚集，均可以减小结石形成的几率，对临床上防治结石具有积极的意义.     

不同草酸/钙摩尔比条件下草酸钙晶体的生长及对HK-2细胞的毒性

研究了不同草酸/钙(Ox/Ca)摩尔比对CaOx晶体在损伤前后的人肾近曲小管上皮细胞(HK-2)表面的生长差异及形成的晶体对细胞的毒性差异. 实验结果表明, CaOx过饱和溶液对正常细胞和损伤细胞均会产生进一步的损伤, 导致细胞活力、 溶酶体的完整性和线粒体膜电位降低, 而细胞内活性氧(ROS)、 细胞骨架的紊乱程度、 磷酯酰丝氨酸(PS)外翻比例和骨桥蛋白(OPN)表达量均增加; 且随着过饱和溶液中Ox/Ca摩尔比的增加而损伤加重. 正常细胞主要诱导二水草酸钙(COD)晶体形成, 且COD的含量与Ox/Ca摩尔比成正相关. 损伤细胞表面主要生成一水草酸钙(COM), 且晶体的数量和聚集程度与Ox/Ca摩尔比成正相关. 相比于正常细胞, 损伤细胞诱导的晶体棱角更加尖锐, 其对细胞的损伤大于棱角圆钝的晶体. 实验结果还表明, 降低CaOx的过饱和度、 减小Ox/Ca摩尔比和修复受损伤的肾上皮细胞均有利于抑制CaOx结石形成.     

脂质体中不同种类羧酸钾对草酸钙晶体生长的调控作用

首次研究了狼磷脂-水脂质体中不同种类羧酯钾对草酸钙晶体生长的调控作用 。加入一元DAc只诱导一水草酸钙（COM）生成。二元K_2tart在其浓度大于1. 0mmol/L时可以诱导三水草酸钙（COT）生成。而加入三元的K_3cit和四元的 K_2edta后， 在不同的浓度下，可以分别诱导COM，二水草酸钙（COD）和COT的生 成。在低浓度（—3.3-17mmol/L）范围，， COD含量达到100%；而在较高浓度(＞ 17mmol/L)时，COD减少，COT含量增加。在不同的浓度区间，无论是COM含量减少， 还是COT含量增加，或者是COD含量的先增加后减少，均与该羧酸钾浓度的对数呈线 性关系。不同羧酯钾抑制COM生长并诱导COD形成的能力顺序为：K_3cit＞K_2edta ＞＞K_2tart-KAC,诱导COT生长的能力顺序为：K_2tart＞＞K_3cit＞K_2edta＞＞ KAc.由此推测抑制草酸钙结石形成的潜在效率依次为：K_3cit＞K_2edta＞＞ K_2tart＞＞KAc.     

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.     

乌梅提取液对草酸钙晶体生长的抑制作用研究

本文研究了水体系中加入乌梅提取液对草酸钙晶体生长的抑制作用,通过FTIR、SEM及XRD等测试方法对所得晶体进行表征。结果表明,不加乌梅提取液的体系中形成的晶体为一水合草酸钙(COM)晶体,加入乌梅提取液后,形成的是二水合草酸钙(COD)晶体,而且COD晶体的尺寸随着乌梅提取液浓度的增大而减小,直至消失,这说明乌梅提取液具有抑制草酸钙晶体生长的作用,且这种抑制作用随乌梅浓度的增大而增大。本文还通过电导率法研究了草酸钙晶体生长的动力学过程,发现乌梅提取液主要能抑制草酸钙晶体的成核过程。     

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.