不同程度减压低氧对大鼠心功能及心肌Ca~（2＋）·Mg~（2＋）－ATPase

不同程度减压低氧对大鼠心功能及心肌Ｃａ￣（２＋）·Ｍｇ￣（２＋）－ＡＴＰａｓｅ的影响孙希武，叶益新，邓希贤（中国医学科学院基础医学研究所，北京１００００５）本文从整体、器官及细胞水平对不同程度减压低氧对大鼠心功能及心肌Ｃａ２＋·Ｍｇ２＋－ＡＴＰａｓｅ...     

猕猴精子获能和顶体反应过程中Ca~（2＋）和Ca~（2＋）－ATPase定位及咖啡因和dbcAMP对顶体反应的影响

用焦锑酸钾原位沉淀法和枸橼酸铅捕获法研究了猕猴精子获能和顶体反应过程中的Ｃａ~（２＋）分布和Ｃａ~（２＋）－ＡＴＰａｓｅ活性。获能前精子头部Ｃａ~（２＋）主要分布于顶体区质膜内外、顶体外膜和顶体内膜内侧，尾部Ｃａ~（２＋）主要分布于线粒体基质，在质膜、致密纤维和轴丝处也有一定分布，在获能过程中Ｃａ~（２＋）进入精子内部，并在头部结合于顶体区质膜内侧和顶体外膜外侧。顶体反应时Ｃａ~（２＋）结合于顶体内膜外侧和由顶体外膜囊泡化形成的囊泡内外，另外还有一些Ｃａ~（２＋）分散存在于顶体内容物中。在ｐＨ９．０条件下，头部Ｃａ~（２＋）－ＡＴＰａｓｅ活性存在于顶体外膜外侧和顶体区质膜外侧，顶体后区质膜无此酶活性。尾部Ｃａ~（２＋）－ＡＴＰａｓｅ存在于质膜、线粒体膜及致密纤维和轴丝处。各处的Ｃａ~（２＋）－ＡＴＰａｓｅ活性在获能和顶体反应过程中一直存在。咖啡因和ｄｂｃＡＭＰ可提高精子运动能力，前者还可显著增加顶体反应率。     

淋巴细胞内pHi、Na~＋－H~＋交换活性与SHRSP关系的研究

本文应用ｐＨ敏感的ＢＣＥＣＦ和Ｃａ敏感的Ｆｕｒａα萤光染料，分别测定雄性。１６周龄ＳＨＲＳＰ和ＷＫＹ循环淋巴细胞ｐＨｉ，Ｎａ￣＋－Ｈ￣＋交换活性和［Ｃａ￣（２＋）］ｉ，结果表明ＳＨＲＳＰ循环淋巴细胞ｐＨｉ、Ｎａ￣＋－Ｈ￣＋交换活性和［Ｃａ￣（２＋）］ｉ均显著高于ＷＫＲ，而细胞缓冲能力在两组大鼠之间没有显著差异。提示在ＳＨＲＳＰ细胞膜可能存在Ｎａ￣＋，Ｈ￣＋交换遗传性缺陷。将两组大鼠的资料合并，经直线回归相关分析发现ｐＨｉ与Ｎａ￣＋－Ｈ￣＋交换活性和ｐＨｉ与［Ｃａ（２＋）］ｉ均呈显著正相关。表明Ｎａ￣＋－Ｈ￣＋交换活性和［Ｃａ￣（２＋）］ｉ参与ｐＨｉ调节．它们之间既相互调节又相互制约。细胞内Ｎａ、Ｃａ和细胞膜Ｎａ￣＋－Ｈ￣＋离子转运系统异常可能是高血压病因中重要因素之一。     

组织中Ca~（2＋）－ATP酶的图像分析仪测定法

在Ｃａ（２＋）－ＡＴＰ酶含量的测定中，我们尝试用图像分析仪测定组织中Ｃａ（２＋）－ＡＴＰ的含量，并将其结果与显微分光光度法进行了比较。表明两种方法的结果一致（Ｐ＞０．０５），而图像分析仪法操作简便、快速、准确，是测定组织中Ｃａ（２＋）－ＡＴＰ酶含量较理想的方法。我们应用该法测定了晕厥心肌中Ｃａ（２＋）－ＡＴＰ酶含量，缺血组织中Ｃａ（２＋）－ＡＴＰ含量明显低于对照组（Ｐ＜０．０１）。     

氧自由基产生体系及丹参素对大鼠心肌线粒体质子ATP酶水解与合成活性的影响

本实验采用ＦｅＳＯ＿４／抗坏血酸体系观察了氧自由基对大鼠心肌线粒体质子ＡＴＰ酶（Ｈ￣＋－ＡＴＰａｓｅ）水解与合成活性的损伤作用及丹参素（ＤＳ－１８２）的保护作用效应。结果表明：ＦｅＳＯ＿４／抗坏血酸体系产生的氧自由基可使线粒体Ｈ￣＋－ＡＴＰａｓｅ水解活性明显升高、合成活性明显下降，丹参素可以防止Ｈ￣＋－ＡＴＰａｓｅ水解活性升高，合成活性下降、显示出良好的保护作用。     

维生素E对冷适应大鼠红细胞膜钠-钾-ATP酶活性及丙二醛含量的影响

目的：研究膳食维生素Ｅ（ＶＥ）增强冷适应的机理。方法：用ＳＤ大鼠为研究对象，分别饲以高ＶＥ饲料（２３０ｍｇ／ｋｇ．饲料）和低ＶＥ饲料（３０ｍｇ／ｋｇ．饲料）。观察大鼠红细胞膜钠－钾－ＡＴＰ酶（Ｎａ＋－Ｋ＋－ＡＴＰａｓｅ）活性和丙二醛（ＭＤＡ）含量的变化。结果：冷适应大鼠红细胞膜Ｎａ＋－Ｋ＋－ＡＴＰａｓｅ活性明显高于对照组（Ｐ＜０．０５），高ＶＥ摄入大鼠红细胞膜Ｎａ＋－Ｋ＋－ＡＴＰａｓｅ活性明显高于低ＶＥ摄入组大鼠（Ｐ＜０．０５）；高ＶＥ摄入组大鼠红细胞膜ＭＤＡ含量明显低于低ＶＥ摄入组大鼠（Ｐ＜０．０５）；膜Ｎａ＋－Ｋ＋－ＡＴＰａｓｅ活性和ＭＤＡ含量间呈明显负相关。结论：膳食ＶＥ可以提高冷适应大鼠红细胞膜Ｎａ＋－Ｋ＋－ＡＴＰａｓｅ活性，降低膜ＭＤＡ含量     

高血压大鼠视网膜组织Ca^2＋酸性磷酸酶组织化学的研究

目的：应用光镜定量酶组织化学方法对正常京都种大鼠（ＷＫＹ）和自发性高血压大鼠（ＳＨＲ）视网膜组织的Ｃａ＾２＋－酸性磷酸酶的分布和活性进行定量观察，结果：Ｃａ＾２＋酸性磷酸酶在ＷＫＹ视网膜组织的活性由强到弱依次为（Ｆ检验，Ｐ〈０．０５）；（１）杆锥细胞内节和外核层；（２）节细胞层；（３）内核层；（４）内网层和外网层；（５）杆锥细胞外节阴性，在ＳＨＲ视网膜组织中，各层Ｃａｓ＾２＋酸性磷酸酶活性下降，以     

高压氧对小鼠肺毛细血管Na~＋－K~＋－ATPase影响的图像分析

采用Ｎａ￣＋－Ｋ￣＋－ＡＴＰａｓｅ电镜细胞化学方法，观察在高压氧（０．２５ＭＰａ）和高压氧中毒情况下（０．５２ＭＰａ）小鼠肺毛细血管Ｎａ￣＋－Ｋ￣＋－ＡＴＰａｓｅ活性的分布、活性强度与超微结构改变之间的联系，并用计算机图像定量分析方法对酶活性进行了１４个参数的定量分析，这些定量参数表明，高压氧条件下。肺毛细血管Ｎａ￣＋－Ｋ￣＋－ＡＴＰａｓｅ活性升高，在高压氧中毒（０．５２ＭＰａ）条件下，肺毛细血管Ｎａ￣＋－Ｋ￣＋－ＡＴＰａｓｃ活性减弱。     

穿心莲提取液减轻心肌缺血－再灌注过程中钙超负荷的机制探讨

本文采用整体犬急性心肌缺血－再灌注模型以探讨穿心莲提取液减轻钙超负荷的机制。结扎冠脉左前降支上１／３处９０ｍｉｎ后再灌注６０ｍｉｎ较持续结扎１５０ｍｉｎ，缺血中心区心肌细胞内Ｃａ２＋增加（Ｐ＜０．０５）、Ｎａ＋明显增加（Ｐ＜０．０１），心肌细胞膜Ｃａ２＋－ＡＴＰａｓｅ活性明显降低（Ｐ＜０．０１），心肌组织ＭＤＡ含量显著增高（Ｐ＜０．０１）。而在再灌注前４５ｍｉｎ静脉给予穿心莲提取液，则见其缺血中心区心肌细胞内Ｃａ２＋降低（Ｐ＜０．０５）、Ｎａ＋明显降低（Ｐ＜０．０１），心肌细胞膜Ｎａ＋－Ｋ＋－ＡＴＰａｓｅ、Ｃａ２＋－ＡＴＰａｓｅ活性明显增加（Ｐ＜０．０１）。心肌组织ＭＤＡ含量显著降低（Ｐ＜０．０１）。说明穿心莲提取液减轻心肌缺血－再灌注过程中钙超负荷与减轻氧自由基危害、保护心肌细胞膜ＡＴＰａｓｅ活性、降低钠超负荷有关。     

多聚Clq诱导免疫细胞的Ca~（2＋）动员

多聚Ｃｌｑ与人Ｔ细胞系Ｊｕｒｋａｔ、Ｂ细胞系Ｒａｎ和Ｍφ系Ｕ９３７细胞表面ＣｌｑＲ相互作用，诱导４５Ｃａ２＋跨膜快速内流，刺激［Ｃａ２＋］ｉ迅速增高，前者可为质膜Ｃａ２＋通道阻滞剂Ｖｅｒａｐａｍｉｌ所阻断，后者能被胞外Ｃａ２＋络合剂ＥＧＴＡ部分抑制，被蛋白酪氨酸激酶（ＰＴＫ）抑制剂Ｇｅｎｉｓｔｅｉｎ完全消除。资料表明，Ｃｌｑ／ＣｌｑＲ系统介导的信号转导机制涉及内Ｃａ２＋和外Ｃａ２＋两者的动员，且与ＰＴＫ有关。     

Press-formable CaO-MgO-SiO(2)-TiO(2)-Ag(2)O glass as a biomaterial

Glass-ceramics were investigated to obtain a glass with a composition of CaO. MgO. 2SiO(2). 0.375TiO(2). 0.007Ag(2)O. The glass melted at 1500 degrees C and could be cast. Crystallization of diopside of this glass is controlled by volume nucleation and growth processes. In a crystallization treatment at 850 degrees -870 degrees C, this glass presented a milky white, semitransparent color. The crystals formed were diopside, their crystal grain diameter was 1-2 micrometer, and crystallization was 15-25%. The bending strength of the glass produced by a crystallization treatment of 25 min at 850 degrees C was 400 MPa, which is suitable for artificial bones. This crystallized glass also was extremely stable, with no weight loss after stability testing in artificial saliva. The softening point, as determined from the viscosity curve, was 830 degrees C, and the crystallization temperature was 895 degrees C. Thus this glass can be press-formed at a temperature of 830 degrees -880 degrees C. Actual press-forming at a pressure of 0.64 MPa was carried out for 40 min at 850 degrees C and resulted in the formation of desired shapes. Given its ready formation into desired shapes and its great strength after crystallization, such glass is applicable for use as artificial bones and as dental roots and crowns.     

Nitric oxide reduces Ca(2+) and Zn(2+) influx through voltage-gated Ca(2+) channels and reduces Zn(2+) neurotoxicity

The translocation of synaptic Zn(2+) from nerve terminals into selectively vulnerable neurons may contribute to the death of these neurons after global ischemia. We hypothesized that cellular Zn(2+) overload might be lethal for reasons similar to cellular Ca(2+) overload and tested the hypothesis that Zn(2+) neurotoxicity might be mediated by the activation of nitric oxide synthase. Although Zn(2+) (30-300microM) altered nitric oxide synthase activity in cerebellar extracts in solution, it did not affect nitric oxide synthase activity in cultured murine neocortical neurons. Cultured neurons exposed to 300-500microM Zn(2+) for 5min under depolarizing conditions developed widespread degeneration over the next 24h that was unaffected by the concurrent addition of the nitric oxide synthase inhibitor N(G)-nitro-L-arginine. Furthermore, Zn(2+) neurotoxicity was attenuated when nitric oxide synthase activity in the cultures was induced by exposure to cytokines, exogenous nitric oxide was added or nitric oxide production was pharmacologically enhanced. The unexpected protective effect of nitric oxide against Zn(2+) toxicity may be explained, at least in part, by reduction of toxic Zn(2+) entry. Exposure to nitric oxide donors reduced Ba(2+) current through high-voltage activated calcium channels, as well as K(+)-stimulated neuronal uptake of 45Ca(2+) or 65Zn(2+). The oxidizing agents thimerosal and 2,2'-dithiodipyridine also reduced K(+)-stimulated cellular 45Ca(2+) uptake, while akylation of thiols by pretreatment with N-ethylmaleimide blocked the reduction of 45Ca(2+) uptake by a nitric oxide donor.The results suggest that Zn(2+)-induced neuronal death is not mediated by the activation of nitric oxide synthase; rather, available nitric oxide may attenuate Zn(2+) neurotoxicity by reducing Zn(2+) entry through voltage-gated Ca(2+) channels, perhaps by oxidizing key thiol groups.     

Automatic determination of ligand purity and apparent dissociation constant (K(app)) in Ca(2+)/Mg(2+) buffer solutions and the K(app) for Ca(2+)/Mg(2+) anion binding in physiological solutions from Ca(2+)/Mg(2+)-macroelectrode measurements

Calibration of Ca(2+)/Mg(2+) macroelectrodes and flurochromes in the nmolar and mumolar range, respectively, require the use of buffer solutions. In these buffers the apparent dissociation constant (K(app)) has to be measured since calculation based on tabulated constants gives variable results. The ligand concentration [Ligand](T) has also to be estimated. The most accurate and general method for measuring both is the ligand optimisation method based on macroelectrode potential measurements, but this iterative method is time consuming, thus limiting its application. This paper describes an automatic program based on the method, which on entering the measured macroelectrode data calculates K(app), [Ligand](T) and the ionised concentration [X(2+)] within minutes. This optimisation method cannot be used at K(app) values greater than 0.1mM, but can be extended into this region if the anion concentration is known. The program has been modified to cover this eventuality. Ca(2+)/Mg(2+) macroelectrodes in conjunction with these programs offer an accurate, routine method for determining K(app) and [Ligand](T) in buffer solutions at the appropriate ionic strength, temperature and pH and the K(app) for divalent cations binding to physiological anions under experimental conditions.     

Matrix metalloproteinase 2 (MMP-2) and their tissue inhibitor 2 (TIMP-2) in gastric cancer patients

BackgroundMatrix metalloproteinase 2 (MMP-2) is able to degrade type IV collagen and its activity is mostly regulated by tissue inhibitor of matrix metalloproteinase 2 (TIMP-2). These proteins might play a role in tumor progression, including gastric cancer (GC).MethodsThe study included 108 individuals, GC patients and healthy subjects. Serum levels of all analyzed markers were evaluated by the immunological methods, while immunohistochemistry was used to assess the expression of these proteins in GC, interstitial inflammatory cells and normal tissues.ResultsThe percentage of positive reactions of MMP-2 and TIMP-2 was higher in GC and inflammatory cells compared to normal tissue, while serum levels of these proteins were statistically lower in GC patients in comparison to healthy subjects. There was a significant positive correlation between TIMP-2 immunoreactivity in inflammatory cells and the presence of lymph node metastasis. Area under ROC curve (AUC) for TIMP-2 was higher than MMP-2, while serum MMP-2 was an independent prognostic factor of GC patients' survival.ConclusionOur findings suggest that TIMP-2 seems to be a predictor of tumor progression, especially for nodal involvement, whereas serum MMP-2 might be useful as an independent prognostic factor of patients' survival.     

EPR Identification of Zr(III) Complexes Formed upon Interaction of (2-PhInd)2ZrCl2 and rac-Me2Si(1-Ind)2ZrCl2 with MAO and MMAO

Reactions of 1 and 2 with MAO and MMAO were monitored by EPR. It was found that MMAO is a stronger reducing agent than MAO. 1 is more prone to reduction than 2 . The reduction of Zr^IV to Zr^III seems to be the essential pathway of some zirconocene catalysts' deactivation. Zr^III species with the following proposed structures can be identified in the 1 /MMAO system: (2-PhInd)₂Zr^III(ⁱBu), (2-PhInd)₂Zr^III(µ-Cl)₂AlⁱBu₂, (2-PhInd)₂Zr^III(µ-Cl)(ⁱBu)AlⁱBu₂, and [(2-PhInd)₂Zr^III]⁺[Me-MAO]⁻. The degree of reduction of Zr^IV species determined by EPR in the catalytic system 2 /MMAO can be masked by the formation of diamagnetic Zr^III/Zr^III dimers. Addition of monomers to the 2 /MAO system promotes reduction ot the zirconium species.

     

Synthesis, characterization and biocompatibility of poly(2-ethyl-2-oxazoline)-poly(D,L-lactide)-poly(2-ethyl-2-oxazoline) hydrogels

A novel thermoreversible hydrogel based on poly(2-ethyl-2-oxazoline)-derived amphiphilic triblock copolymer, poly(2-ethyl-2-oxazoline)-poly(D,L-lactide)-poly(2-ethyl-2-oxazoline) (PEOz-PLA-PEOz), was developed. The synthesis of PEOz-PLA-PEOz was carried out by coupling monohydroxylated PEOz-PLA diblocks with adipoyl chloride as coupling agent and dimethylamino pyridine as catalyst. The tube inverting and rheological tests showed that triblock copolymers had sol-gel-sol transition behavior with increasing temperature, and the gelation was found to be thermoreversible. The critical gelation concentration, the sol-gel transition temperature at a given concentration depended on the EOz/LA ratio and the molecular weight of PEOz. Scanning electron microscopy observation revealed that the resultant bulky gel exhibited an interconnected porous three-dimensional (3D) microstructure after freeze-drying. In addition, the hydrogels showed good cytocompatibility in vitro. MTT assays revealed that the human skin fibroblast cells encapsulated within the hydrogels were viable and proliferated inside the 3D scaffold. This newly described thermoreversible hydrogel demonstrated attractive properties to serve as cell matrix for a variety of tissue engineering applications or pharmaceutical delivery vehicles.     

Deletion (2) (q37)

We report on a 5-month-old girl with widely spaced nipples, redundant nuchal skin, coarctation of the aorta, anal atresia with distal fistula, postnatal growth retardation, hypotonia, and sparse scalp hair. Initial clinical assessment suggested the diagnosis of Ullrich-Turner syndrome. Chromosome analysis showed a 46,XX,del(2)(q37) karyotype in peripheral lymphocytes. We compare her findings to those of other reported patients with terminal deletions of 2q. © 1994 Wiley-Liss, Inc.     

Oxidative polymerization of 2-(2-butenyl)- and 2-(3-methyl-2-butenyl)-6-methylphenol

2-(2-Butenyl)-6-methylphenol ( 1a ) and 2-(3-methyl-2-butenyl)-6-methylphenol ( 1b ) were oxidatively polymerized in the presence of a copper-pyridine catalyst to yield poly[oxy-2-(2-butenyl)-6-methyl-1, 4-phenylene] ( 2a ) and poly[oxy-2-(3-methyl-2-butenyl)-6-methyl-1,4-phenylene] ( 2b ) with molecular weights >10⁴. The polymerization rates were in the order 1b > 1a > 1a > 2,6-dimethylphenol ( 3 ), and this order agreed with those of the rate constant of the electron-transfer step and of the redox potential. The 2-butenyl and 3-methyl-2-butenyl group in 2 showed enough chemical reactivity for addition of bromine and epoxidation.