牛磺酸钙的合成研究

利用中和反应合成了牛磺酸钙 ,用元素分析和核磁共振谱确定了其组成为Ca(NH2 CH2 CH2 SO3) 2 ,并测定了它的溶解度。该方法简单 ,产率和纯度较高     

牛磺酸对大鼠急性运动后自由基代谢、膜流动性及钙转运变化的影响

５０只雄性Ｗｉｓｔａｒ大鼠（８０ １００ｇ）,随机分为对照组（Ｇ１）,急性运动组（Ｇ２）,急性运动＋牛磺酸组（Ｇ３）,力竭运动组（Ｇ４）,力竭运动＋牛磺酸组（Ｇ５）。牛磺酸补充方式为每日灌服１次（５００ｍｇ／ｋｇ）。喂养２周后,进行负重游泳,测定血液、线粒体和肌浆网各生化指标变化。结果显示“牛磺酸有增加大鼠游泳力竭时间的趋势（０．０５＜Ｐ＜０．１０）;运动后即刻,Ｇ３组ＢＵＮ明显低于Ｇ２组（ｐ＜０．０５）;Ｇ３组ＲＢＣ、血浆及心肌线粒体ＭＤＡ含量明显低于Ｇ２组（Ｐ＜０．０５）;Ｇ３组ＲＢＣ及心肌线粒体ＧＳＨ＿Ｐｘ活力明显高于Ｇ２组（Ｐ＜０．０５）;Ｇ３组心肌线粒体膜荧光偏振度Ｐ明显低于Ｇ２组（Ｐ＜０．０５）。Ｇ３组ＳＲＣａ２＋ ＡＴＰａｓｅ活性和摄钙率明显高于Ｇ２组（Ｐ＜０．０５）。力竭后２４小时,Ｇ５组ＲＢＣ、血浆及心肌线粒体ＭＤＡ含量明显低于Ｇ４组（Ｐ＜０．０５）。以上结果表明,牛磺酸可以通过抗自由基损伤,稳定生物膜和调节钙转运等途径对抗运动性疲劳。     

45Ca标记复合钙化合物示踪钙生物动力学观察

目的用放射性核素^45Ca标记4种钙制剂化合物，并观察和示踪其生物利用度。方法用^45Ca标记葡萄糖酸钙、柠檬酸钙、碳酸钙和L-苏糖酸钙，测定大鼠心、肝、脾、肾、脑、胃、肠、血液、粪便和尿中钙离子吸收含量和生物利用度。结果①^45Ca标记的钙制剂具有较高的放射性活度、较稳定的组织标准曲线和回收率。②示踪4种化合物生物利用度变化显示，有机钙化合物较无机钙化合物更利于组织的吸收。结论^45Ca标记钙制剂生物示踪方法具有灵敏、客观、准确和稳定的特点。     

EDTA络合滴定法滴定钙易达片中螯合L—天门冬氨酸钙中钙的含量

目的：通过实验确定EDTA络合滴定法测定螯合型L－天门冬氨酸钙中钙含量的可行性。方法：利用在PH＝11．0的条件下,L－天门冬氨酸（螯合）钙的稳定性明显小于EDTA络合钙的特点,采用EDTA络合滴定法测定钙易达片中L－天门冬氨酸钙中钙的含量。结果平均回收率为102．46％,RSD为1．02％（n=5),结论采用EDTA络合滴定法测定螯合型L－天门冬氨酸钙中钙含量的方法可行,结果准确可靠。     

正常和白内障晶体上皮环磷酸腺苷与钙-钙调蛋白的研究

本文测定了人晶体上皮环磷酸腺苷、钙、钙调蛋白的含量,分析了它们之间的相关性,并与老年性白内障晶体相比较.结果是正常晶体钙与cAMP呈负相关性,钙调蛋白与cAMP呈正相关性,提示正常人晶体上皮的Ca-CaM系统与cAMP系统关系密切,CAMP促使晶体排除钙,而cAMP环化酶对钙-钙调蛋白敏感.老年性白内障晶体上皮cAMP含量下降、钙含量升高,cAMP与钙呈负相关性,提示白内障晶体cAMP含量的降低可能与钙含量升高有关,是白内障形成的可能原因之一.     

脑脊液与血离子钙测定及其稳定性观察

离子钙又称游离钙(iCa),临床化学定义为存在于生物体液内的水合钙离子(Ca~(2 )12H_2O).早在1934年Mclean与Hastings通过实验证明了血液中只有这部分钙具有生理生化活性.目前,离子钙测定较好的方法是离子选择电极法(ISE),多数实验室在用于监测体内钙的代谢情况时基本上都是测血液的总钙含量.血浆游离钙的测定,抗凝剂通常选用肝素,但肝素具有结合钙的作用,可使游离钙的测定结果偏低.血清游离钙的测定需经过离心分离等手续,容易使CO_2从血中逸出,致使血液偏碱,甚至可超出仪器允许的pH工作范围,致离子钙测定结果下降.加之临床上检测脑脊液离子钙甚少,为此,我们参考文献(中华神经外科杂志,1994;4:244)的方法对22例脑脊液、血离子钙同时进行了检测,并对脑脊液离子钙的稳定性作了观察,现报道如下.1 材料与方法     

牛磺酸对长期大强度运动训练后大鼠自由基代谢、膜流动性及钙转运的影响

70只雄性Wistar大鼠（80-100g）,随机分为3组：对照组（G1）、游泳训练组（G2）和游泳训练＋牛磺酸组（G3）。牛磺酸补充方式为每日灌服1次（500mg／Kg）。递增负荷训练6周,观察牛磺酸对长期大强度运动训练后大鼠自由基代谢、膜流动性及钙转运的影响。结果显示：运动后即刻,G3组血NH3、BLA、BUN明显低于G2组（P＜0．05）;运动后24小时,G3组血NH3、BLA与对照组比较已无显著性差异（P＞0．05）,而G3组BUN明显低于G2组（P＜0．05）。运动后即刻及24小时,G3组RBC、血浆及心肌线粒体MDA含量明显低于G2组（P＜0．05）;G3组RBC及心肌线粒体GPX活力明显高于G1和G2组（P＜0．05）;G3组心肌线粒体膜荧光偏振度P明显低于G2组（P＜0．05）;G3组心肌线粒体Ca2+浓度明显低于G2组（P＜0．05）;G3组SRCa2+－Atpase活性和摄钙率明显高于G2组（P＜0．05）。以上结果表明,牛磺酸的抗自由基损伤,稳定生物膜和调节钙转运作用可能是其对抗运动性疲劳的重要机制。     

全血中不同形态钙含量测定的实验条件探讨

钙在人体代谢中起重要作用,它不仅是骨骼和生物膜的结构成份,而且对维持细胞膜的电荷,结构和功能都起重要作用。血液中的钙以两种形态存在,游离钙和与蛋白或有机酸形成的结合钙。长期以来临床测定血液中的总钙以表示人体钙代谢情况,事实上从动态、吸收、利用等实际生物学意义来说,最重要的只是其中的游离钙,因此分清血中不同形态的钙含量,特别是游离钙的量,对于临床工作有重要的指导意义。     

细胞核钙研究进展

核钙浓度在细胞有丝分裂、细胞凋亡、基因转录等活动中发挥着重要的调节作用。钙经核膜转运时，CD38可能在其中起重要作用。并且，核膜上存在着ET－1受体，其作用和意义尚有待进一步研究。[Ca^2 ]n(核内钙浓度）升高后，在CaM激酶（钙调蛋白激酶IV）作用下，通过磷酸化的CREB，调节基因表达，产生新的蛋白质，在神经系统，这种作用可能与神经元可塑性有关。研究核钙变化的调控及其在核反应中的意义，对阐明疾病的发病机制及防治有重要价值。     

钙动力学变化在重症休克血管反应性低下发生中的作用

目的：研究血管平滑肌钙动力学变化在重症休克血管反应性降低中的作用．方法：复制大鼠失血性休克模型，测定脊斜肌细动脉对去甲肾上腺素（ＮＥ）反应性；用激光共聚焦显微镜测定单个平滑肌细胞钙动力学变化；观察ＡＴＰ敏感钾通道（ＫＡＴＰ）阻滞剂优降糖对血管反应性和钙动力学影响．结果：大鼠失血休克后１～２小时细动脉对ＮＥ反应性显著下降，ＮＥ升高细胞内钙离子浓度的作用明显减弱，以外钙内流减弱最为明显．优降糖明显提高休克时ＮＥ对平滑肌细胞内钙离子的升高作用，改善细动脉对ＮＥ反应性．结论：重症失血性休克血管反应性低下与ＫＡＴＰ通道开放导致细胞外钙内流减少有关．优降糖能提高血管反应性为临床治疗休克提出了一种新的途径     

Determination of the oxidation state of Tc in 99Tc(Sn)EHDP, 99mTc(Sn)EHDP, 99Tc(Sn)MDP and 99mTc(Sn)MDP complexes. Characterization of Tc(III)-, Tc(IV)- and Tc(V)EHDP complexes

The oxidation state of complexed Tc was determined, by performing paper and thin-layer chromatography during potentiometric titrations. Both titrations of Sn(II) with TcO₄⁻ and of TcO₄⁻ with Sn(II) were performed at pH 2.5, 7.0 and 12.0. Differences were found in the number of electrons transferred to 1 mol of TcO₄⁻, n, in the titration solutions at the end point of a direct and a reversed titration. The oxidation state of Tc changes during a titration with the titration degree. It was possible to obtain almost pure Tc(III)-, Tc(IV)- and Tc(V)EHDP complexes, depending on the pH, titration mode and titration degree. These TcEHDP complexes were analyzed by u.v./vis spectrometry, anion-exchange HPLC on Aminex A-28, gel chromatography on Biogel P₄ and extraction with oxine in chloroform. The spectra of the pure Tc(III), Tc(IV) and Tc(V) species were calculated. Adsorption of these complexes on calcium phosphate increased in the order Tc(V) < Tc(IV) < Tc(III). From the chromatographic characterizations it was concluded that in the ^99mTc(Sn)EHDP bone scanning agent Tc is tetravalent. An analogous (though less elaborate) investigation was performed on the Tc(Sn)MDP complex.     

烧伤后血与血钙浓度变化与补钙疗效分析

目的：寻找烧伤后血钙降低的规律与最佳补钙时机。方法：取烧伤后20天内的未补钙组与补钙一组和补钙二组各30例，进行组问对照。观察各组血钙及其它离子的变化。结果：三组血钙浓度均低于正常值(2．25mmol／L～2．75mmol／L)，但以未补钙组烧伤后血钙降低明显，第三天达最低值，持续时间与烧伤严重程度成正比，一般在伤后三周趋向恢复：补钙一组(连续5天补钙)血钙变化最小，补钙二组(隔日补钙10天)次之。结论：烧伤早期补钙可维持血钙浓度，早期连续补钙5天较隔日补钙10天效果为佳。     

A reproducible nonlethal animal model for studying cyanide poisoning

Previous studies using bolus intravenous injections of sodium cyanide have been used to model the sudden exposure to high concentrations of cyanide that could occur on the battlefield. This study was designed to develop a model that would simulate the type of exposure to cyanide gas that could happen during actual low-level continuous types of exposure and then compare it with the bolus model. Cardiovascular and respiratory recordings taken from anesthetized dogs have been used previously to characterize the lethal effects of cyanide. The intravenous, bolus injection of 2.5 mg/kg sodium cyanide provides a model in which a greater than lethal concentration is attained. In contrast, our model uses a slow, intravenous infusion of cyanide to titrate each animal to its own inherent end point, which coincides with the amount of cyanide needed to induce death through respiratory arrest. In this model, therapeutic intervention can be used to restore respiration and allow for the complete recovery of the animals. After recovery, the same animal can be given a second infusion of cyanide, followed again by treatment and recovery, providing a reproducible end point. This end point can then be expressed as the total amount of cyanide per body weight (mg/kg) required to kill. In this study, the average dose of sodium cyanide among 12 animals was 1.21 mg/kg, which is approximately half the cyanide used in the bolus model. Thus, titration to respiratory arrest followed by resuscitation provides a repetitive-use animal model that can be used to test the efficacy of various forms of pretreatment and/or therapy without the loss of a single animal.     

How much calcium is too much calcium for coronary computerized tomographic angiography?

The coronary artery calcium (CAC) score above which it is recommended that coronary computerized tomographic angiography (CTA) not be performed has been steadily increasing. Currently, calcium scores > 1000 are thought to prohibit CTA accurate interpretation. However, a reasoned approach suggests that there is no absolute upper limit that applies to all patients and imaging centers. To anticipate the problems posed by calcium, a CAC scan must be obtained before CTA. Understanding the clinical goals of the CTA and the source and recognition of CAC-based imaging artifacts can enable accurate clinical CTA examinations even in the setting of high calcium scores.     

Rationale and design of the coronary artery calcium consortium: A multicenter cohort study

Background

Although coronary artery calcium (CAC) has been investigated for over two decades, there is very limited data on the association of CAC with cause of death. The CAC Consortium is a large ongoing multi-center observational cohort of individuals who underwent non-contrast cardiac-gated CAC testing and systematic, prospective, long-term follow-up for mortality with ascertainment of cause of death.

磷酸钙骨水泥的研究进展

磷酸钙骨水泥(CPC)是一种新型的自固型、非陶瓷型骨水泥.众多研究表明,它具有良好的生物相容性、骨传导性、可降解性及可塑性等优点,临床上可用于非负重部位骨缺损的修复、药物或生物因子载体以及松质骨螺钉的加固.作者对近年来CPC的研究概况进行了综述.CPC可望成为新一代骨替代物,具有广泛的应用前景.     

钙阻断剂异博定的辐射防护作用

本研究发现钙阻断剂异博定对于¹⁸⁷CsY射线致死量照射的小鼠具有明显的辐射防护作用。照前15分钟腹腔注八或照前30分钟口服给予异博定最大耐受量可使受照小鼠分别获得1.32和1.24的剂量减低系数(DRF)。异博定给药的小鼠6 GY照后9天的股骨骨髓有核细胞计数或外周血白细胞计数都明显的高于照射对照。     

Milk of calcium pericardial effusion: Case report

A patient with milk of calcium (MOC) pericardial fluid secondary to radiation therapy is presented. We have been unable to identify a previous report of MOC pericardial fluid.     

Assessment of calcium scoring performance in cardiac computed tomography

Electron beam tomography (EBT) has been used for cardiac diagnosis and the quantitative assessment of coronary calcium since the late 1980s. The introduction of mechanical multi-slice spiral CT (MSCT) scanners with shorter rotation times opened new possibilities of cardiac imaging with conventional CT scanners. The purpose of this work was to qualitatively and quantitatively evaluate the performance for EBT and MSCT for the task of coronary artery calcium imaging as a function of acquisition protocol, heart rate, spiral reconstruction algorithm (where applicable) and calcium scoring method. A cardiac CT semi-anthropomorphic phantom was designed and manufactured for the investigation of all relevant image quality parameters in cardiac CT. This phantom includes various test objects, some of which can be moved within the anthropomorphic phantom in a manner that mimics realistic heart motion. These tools were used to qualitatively and quantitatively demonstrate the accuracy of coronary calcium imaging using typical protocols for an electron beam (Evolution C-150XP, Imatron, South San Francisco, Calif.) and a 0.5-s four-slice spiral CT scanner (Sensation 4, Siemens, Erlangen, Germany). A special focus was put on the method of quantifying coronary calcium, and three scoring systems were evaluated (Agatston, volume, and mass scoring). Good reproducibility in coronary calcium scoring is always the result of a combination of high temporal and spatial resolution; consequently, thin-slice protocols in combination with retrospective gating on MSCT scanners yielded the best results. The Agatston score was found to be the least reproducible scoring method. The hydroxyapatite mass, being better reproducible and comparable on different scanners and being a physical quantitative measure, appears to be the method of choice for future clinical studies. The hydroxyapatite mass is highly correlated to the Agatston score. The introduced phantoms can be used to quantitatively assess the performance characteristics of, for example, different scanners, reconstruction algorithms, and quantification methods in cardiac CT. This is especially important for quantitative tasks, such as the determination of the amount of calcium in the coronary arteries, to achieve high and constant quality in this field. Electronic Publication     

Radiofrequency-induced carcinogenesis: cellular calcium homeostasis changes as a triggering factor

The aim was to study the effects of radiofrequency (Rf) in a mice strain characterized by age-determined carcinogenesis of lymphatic tissues. Mice were treated with a 1?h/week Rf exposure for 4 months. A group submitted to sham exposure was used as control animals. The evolution of carcinogenesis was followed up to 18 months. The maximal life span of control mice was about 24 months. All dead animals were clinically and histologically examined to give an age-determined comparative quantification of the evolving carcinogenesis. A radiocalcium tracer method permitted the evaluation of Rf effects on transmembrane transport of extracellular calcium at 1 and 24?h after exposure. The determination of induced lipid peroxidation completed this second study. The findings show that Rf provoked an earlier general lymphocyte cell infiltration, formation of lymphoblastic ascites and extranodal tumours of different histological types, as well as an increased early mortality. The results suggest that in Rf-exposed mice, carcinogenesis may be induced earlier and with different pathological forms than in control animals. The modifications in cellular calcium homeostasis and the age-determined thymus involution appear to be important factors involved in this carcinogenesis process.