Regulation of Content of Malondialdehyde by Siqi Decoction via Increasing Activity of Superoxide Dismutase in Blood Serum of Rats with Myocardial Ischemia

Effect of Siqi decoction on myocardial ischemia is to prevent cardiac myocyte membrane from damage associated with oxygen free radicals related to NO. To research the regulatoin of the content of malondialdehyde by Siqi decoction, an index of lipid peroxidation, via increasing activity of superoxide dismutase in blood serum of rats with Myocardial Ischemia, the model of myocardium ischemia was made in Wistar rats with posterior pituitary injection through vein in tail. Siqi decoction, Diaoxinxuekang(DK) and...     

A General Procedure for Synthesis of NG-Alkyl,and NG-Aryl-L-Arginines as Potential Nitric Oxide Synthase inhibitors

A general procedure for the synthesis of N^G-alkyl, and N^G-aryl-L -arginines with relatively high overall yield is reported. The key step involved the coupling of protected L -ornithine 4 with isothiourea 7 to give the fully protected N^G-aryl-L -arginine derivative 8 . Subsequent deprotection of 8 in acidic condition provided the final target compound 9 with an overall yield of more than 80%.     

聚N,N-双水杨醛乙二胺合钴修饰超微电极的制备及其在一氧化氮测定中应用的研究

通过电化学聚合法制备了聚Ｎ，Ｎ－双水杨醛乙二胺合钴［ｐｏｌｙＣｏ（Ｓａｌｅｎ）］修饰超微电极，研究了该修饰电极的电催化性质及其在一氧化氮（ＮＯ）测定中的应用．实验结果表明，ｐｏｌｙＣｏ（Ｓａｌｅｎ）修饰超微电极对ＮＯ的测定有高的灵敏度，ＮＯ的浓度在２．０×１０－８～２．８×１０－６ｍｏｌ／Ｌ范围内，电流与浓度呈良好的线性关系，线性相关系数为０．９９９８，检出限为１．０×１０－８ｍｏｌ／Ｌ；该电极进一步修饰Ｎａｆｉｏｎ后，生物体中常见的物质如抗坏血酸、儿茶酚胺类神经递质的代谢物、ＮＯ的氧化产物ＮＯ－２等不干扰测定．本传感器可以满足ＮＯ在体分析的需要．     

一氧化氮标准储备水溶液浓度的测定及稳定性分析

用紫外-可见分光光度法,分别使用酸性和中性两种G riess-Saltzm an(GS)试剂对NO标准储备液的浓度及稳定性进行了分析。结果表明NO在酸性GS试剂中其检测灵敏度远大于中性GS试剂中的灵敏度(近19倍),但在酸性GS试剂中NO2-对NO的检测有干扰,其灵敏度约为NO的1/3;而在中性GS试剂中,当NO2-浓度小于10μmol/L时,NO2-对NO的检测没有影响。实验室制备的一氧化氮饱和溶液的浓度在10℃时为2.7 mmol/L,20℃时为2.0 mmol/L,其稳定期均为3 d。     

A Novel Nitric Oxide Cellular Biosensor Based on Red Blood Cells Immobilized on Gold Nanoparticles

Abstract

We have developed a novel nitric oxide (NO) cellular biosensor based upon the immobilization of red blood cells (RBCs) onto nanometer‐size colloidal gold that is attached to an electrochemically pretreated glassy carbon electrode via the bridging of an ethylenediamine monolayer. The biosensor has been characterized by atomic force microscopy (AFM), scanning electron microscopy (SEM), and electrochemistry. The immobilized RBCs display an excellent electrocatalytic response to nitric oxide. The electrocatalytic currents are proportional to the NO concentration in the range from 1.0×10^–8 to 1.0×10^–6 M and the detection limit is as low as 5.0×10^–9 M (S/N=3). Furthermore, the biosensor is very stable and relatively free of potential interference.     

Metalloporphyrin and heteropoly acid catalyzed oxidation of CNOH bonds in an ionic liquid: biomimetic models of nitric oxide synthase

Water soluble iron(III) porphyrins and phosphotungstic acid in an ionic liquid are effective catalysts for the H₂O₂ mediated oxidation of the CNOH bond in N-hydroxyarginine and other oximes. The carbonyl compounds generated as the oxidation products can be easily isolated from the reaction media. These systems serve as biomimetic models of nitric oxide synthase (NOS) and the catalyst immobilized in an ionic liquid can be easily recycled and reused.     

Cyclic Voltammetry and Structural Studies of Nitric Oxide Monolayers Adsorbed on Pt(111)

The structural analysis of the adsorption of NO monolayers on Pt(111) from solution has been explored by cyclic voltammetry (CV) and X‐ray photoelectron spectroscopy (XPS) techniques. The monolayers were formed from acid solutions saturated with NO gas as well and from nitrite solutions in sulfuric acid. Results by both techniques indicate a maximum coverage of 0.2 monolayers as well as the presence of NO molecularly adsorbed on the surface with different orientations. The voltammetric oxidation of NO gives rise to two peaks separated in the voltammogram by 50 mV. This value is in agreement with the theoretical value of 9 kJ corresponding to the difference between different adsorption sites. A mechanism for the surface mediated oxidation process from adsorbed NO to NO₂ under potential control is proposed.     

肿瘤抑制因子WT1对人的诱导型一氧化氮合成酶基因的转录调节作用

将人的诱导型一氧化氮合成酶(hiNOS)启动子构建在带荧光素酶基因的载体pGL3-basic上, 构建成用荧光素酶为系统的启动子, 以研究载体p8.3iNOS. 结果显示, 肾母细胞肿瘤抑制因子(WT1)能够有效地抑制hiNOS启动子的转录; 且WT1的4个选择性剪接本的抑制效果有所不同, 其中WT1(-/-)在两种肝癌细胞(HepG2和Hep3B)中对hiNOS的表达均具有最强的抑制作用, 并且抑制效果具有剂量依赖性, 用Western blot检测结果进一步证实HepG2细胞中WT1(-/-)过量表达能下调hiNOS表达. 以上结果说明WT1在肝癌细胞中对人的hiNOS具有转录调节作用.     

Investigation on the effects of diamide on NO production in vascular endothelial cells (VEC)

Nitric oxide (NO) controls several physiological functions of the cardiovascular system. The study on the effect of diamide (N₂H₄·H₂O) on NO production in vascular endothelial cells (VEC) may provide significant reference for VEC’s modeling in studying cardiovascular diseases. The objective of this study was to elucidate how high concentration diamide (V_diamide/V_{culture miedium}=5 ml/l) and low concentration diamide (V_diamide/V_{culture miedium}=0.5 ml/l) affect NO production in a human endothelial cell line (ECV304). After cells were incubated with diamide (5 or 0.5 ml/l) for 4, 6, 8 or 10 h, respectively, the amounts of NO metabolites released by the cells were quantitated and the degree of damage of VEC was observed using microscope. The results showed that NO production in VEC tended to decrease with the lapse of time in the 0.5 ml/l diamide group. In the 5 ml/l diamide group, on the contrary, NO production in VEC tended to increase with the lapse of time. At the same time, from the morphologic observation, the VEC were damaged severely after treated with 5ml/l diamide. So it could be concluded that the severe damage induced by high concentration diamide would have triggered the express of inducible nitric oxide synthases (iNOS). Just for the expresssion of iNOS, NO production in VEC treated with high concentration diamide occurred abnormally in contrast to the 0.5 ml/l group.     

A New Ultramicrosensor for Nitric Oxide Based on Electropolymerized Film of Nickel Salen

Abstract

A new amperometric ultramicrosensor for the determination of nitric oxide (NO) is described. The ultramicrosensor, which is based on an electropolymerized film of ethylenebis(salicylideneiminate) nickel [Ni(salen)] and Nafion, shows a low detection limit, high selectivity and sensitivity to NO determination. The oxidation current (measured by a differential pulse amperometric method) is linear with NO concentration ranging from 1.0x10^?8 to 4.0x10^?6 mol/L with a calculated detection limit, at a signal to noise ratio of three, equal to 5.0x10^?9 mol/L. Some endogenous electroactive substances in biological tissues, such as dopamine, 5-HT and nitrite do not interfere with NO determination at the concentrations higher than those in biological systems. The ultramicrosensor could be employed for in vivo measurements of NO. The mechanism of the response of the ultramicrosensor to NO is also studied.     

Synthesis and Properties of a pH‐Insensitive Fluorescent Nitric Oxide Cheletropic Trap (FNOCT)

The synthesis and properties of the new fluorescent nitric oxide cheletropic trap (FNOCT) 14 , designed for the trapping and quantification of nitric oxide (NO) production in chemical and biological systems, is described (Scheme 3). The dicarboxylic acid 14 and the corresponding bis[(acetyloxy)methyl] ester derivative 15 of the FNOCT contain a 2‐methoxy‐substituted phenanthrene group as fluorophoric unit. The fluorescence of the reduced NO adduct of this FNOCT (λ_exc 320 nm, λ_em 380 nm) is pH‐independent. Trapping experiments were carried out in aqueous buffer solution at pH 7.4 with nitric oxide being added as a bolus as well as being released from the NO donor compound MAHMA NONOate (= (1Z)‐1‐{methyl[6‐(methylammonio)hexyl]amino}diazen‐1‐ium‐1,2‐diolate), indicating a trapping efficiency of ca. 50%. In a biological application, nitric oxide was scavenged from a culture of lipopolysaccharide‐stimulated rat alveolar macrophages. Under the applied conditions, a production of 11.1 ± 1.5 nmol of NO per hour and per 10⁵ cells was estimated.     

两种含锌化合物对慢性染铅大鼠海马NADPH-d阳性神经元影响的比较

为探讨硫酸锌(ZnSO4)和牛磺酸锌(TZC)拮抗铅对学习记忆的损害的不同,采用NADPH-黄递酶(NADPH-d)组化,观察了饮用含0.2g／L醋酸铅(PbAc)饮水和含不同剂量(5．0,15．0g／kg)ZnSO4、(5．9、17．7g／kg)TZC饲料喂养的大鼠海马一氧化氮合酶(NOS)活性的变化。结果表明,各补锌组均不同程度地缓解铅致NOS活力减低,铅 低TZC组、铅 高ZnSO4组和铅 低ZnSO4组大鼠海马神经元的NOS活性明显高于染铅组,其中铅 低TZC组的保护作用最显著,而铅 高TZC组的NOS活性明显低于对照组,而接近染铅组水平。结论是锌对抗铅的毒性作用与锌的化学结合形式、锌的剂量密切相关。     

Effect of Electrohydraulic Shock on Activity of Aluminum/Nickel/Copper Catalysts in the Reaction of Reduction of NO by Carbon(II) Oxide

We have studied the reaction of NO and CO on aluminum/nickel/copper catalysts obtained under short high-voltage discharge conditions. We have established that electrohydraulic shock affects formation of heterogeneous catalytic systems and increases the activity of catalysts during simultaneous removal of nitrogen and carbon oxides from gaseous exhausts.     

基于表面活性剂单分子层修饰碳糊电极的一氧化氮电化学传感器及其应用

报道了一种表面活性剂单分子层修饰碳糊电极,并用于NO的高灵敏电化学检测。研究表明,表面活性剂通过烷基链在电极表面形成的疏水性单分子层微环境对NO的电化学响应具有较好的促进作用。其中,阳离子表面活性剂十六烷基三甲基溴化铵(CTAB)对NO的电化学氧化表现出最强的催化活性和增敏作用。在Nafion膜覆盖的CTAB修饰碳糊电极上,NO的安培响应与其浓度在3.6×10-8～1.8×10-5mol/L范围内呈良好的线性关系,检出限为1.8×10-8mol/L。该电极作为低成本、高灵敏的NO电化学传感器,被成功应用于大鼠肺组织细胞中NO释放的实时监测。     

冷应激对铜预投大鼠血清铜锌代谢、SOD活性及GSH含量的影响

为揭示应激对体内微量元素代谢的影响和机制，预先给予大鼠不同水平的铜3周后，采用冷束缚法使大鼠产生应激，测定了血清铜、锌水平及超氧化物歧化酶(SOD)活性、还原型谷胱甘肽(GSH)和丙二醛(MDA)含量。结果表明，高铜给予没有对清洁级大鼠生长产生明显的影响．血清铜、锌及铜锌比值变化不明显，但适量的铜给予能显著提高血清中SOD活性和GSH含量；冷应激处理后大鼠血清中Cu水平下降，Zn水平升高，同时SOD消耗降低，而GSH含量显著升高。表明冷应激可使大鼠体内铜锌代谢及SOD活性和GSH含量发生变化，适量的铜给予在应激状况下才发挥出积极的生理作用。     

Analytical Methods for Determining the Concentration Ratio in Mixtures of Trioctylphosphine Oxide and Di(2-Ethylhexyl)Phosphoric Acid

Abstract

Analytical methods are described for determining the concentration ratio of trioctylphosphine oxide (TOPO) and di(2-ethylhexyl)phosphoric acid (D₂ EHPA) in hydrocarbon solvents or in mixtures where the D₂ EHPA is the solvent. The Electron Spectroscopy for Chemical Analysis (ESCA) method was used to analyze the mixtures for the relative amounts of phosphine oxide-phosphorus to phosphoric acid-phosphorus as well as the variance with the mixture composition of the Ols/P2p signal intensity. The nmr signal strength of the protons of the oxymethylene group of the D₂ EHPA and the signal strength of the other protons of D₂ EHPA and TOPO were measured in solutions of varying concentrations of D₂ EHPA and TOPO. Mass spectral comparisons of the molecular ion strengths of TOPO and D₂ EHPA were also correlated with mixture composition.     

Effects of Arsenic Compounds on Proliferation and Nitric Oxide Synthesis in C3H 10T 1/2 Murine Fibroblasts

Exposure to arsenic, either through chronic consumption of contaminated water or inhalation, is associated with increased risk of cancer, yet the mechanism by which arsenicals promote neoplastic change remains undefined. The carcinogenic process involves the formation of heritable genetic changes in the DNA of normal cells and this process may be enhanced by environmental agents that increase cellular proliferation, increase DNA damage and decrease the ability to repair damage or cause immunosuppression. We describe the inhibition of cellular proliferation of C3H 10T1/2 murine fibroblasts in the presence of 1.0 μM arsenate or arsenite; yet cacodylic acid had no significant effect on cell growth in culture at this concentration. Both arsenate and cacodylate, at micromolar concentrations, slightly stimulated cell growth and cell density when cells were treated with interferon-γ/lipopolysaccharide (IFN-γ/LPS). At 1 μM , arsenate and cacodylate also slightly increased IFN-γ/LPS-induced nitric oxide (NO) synthesis in this cell line, consistent with the increase in cell number observed, whereas 1 μM arsenite significantly increased NO production on a per-cell basis. In contrast, arsenite significantly inhibited NO synthesis at concentrations above 10 μM arsenite as, to a lesser extent, did arsenate and cacodylate. These results suggest that ingestion of arsenicals could alter cellular generation of NO and interfere with its associated physiological functions. © 1997 by John Wiley & Sons, Ltd.     

Theoretical study of NO adsorption/dissociation on Pd (100) and (111) surfaces

Both adsorption and dissociation of the diatomic molecular NO on Pd (100) and (111) surfaces are studied using the extended London‐Eyring‐Polyani‐Sato (LEPS) method constructed by means of 5‐MP (the 5‐parameter Morse potential). All critical characteristics of the system that we obtain, such as adsorption geometry, binding energy, eigenvalues for vibration, are in good agreement with the experimental results. On Pd (100) surface, NO prefers to adsorb in fourfold hollow site (H) uprightly at low coverage. With increase in the coverage NO gradually tilts in fourfold hollow and bridge sites. For NO? Pd (111) system, two adsorption states are found at low coverage, of which one adsorption state is the B(tilt) state that the centroid of NO projects at bridge site, another (H? B? H state) that NO almost parallels to the (111) surface with the vibration frequency of 610 cm^?1, but the frequency is near to that of the atoms, which is easy to be ignored in experiments. At high coverage, two transitional states (BH and HT) are found. NO is difficult to dissociate on Pd (100) and (111) surfaces. Especially for NO? Pd (111) system, the three‐well‐potential dissociation mode is initially put forward to show the remarkable dissociation process with two dissociation transitional states of NO on Pd (111). Copyright © 2008 John Wiley & Sons, Ltd.     

New sesquiterpenes from Inula japonica Thunb. with their inhibitory activities against LPS-induced NO production in RAW264.7 macrophages

Twenty-two new sesquiterpenes were isolated from the aerial parts of Inula japonica Thunb., together with fifteen known ones. Their structures were determined by detailed spectroscopic analysis, X-ray diffraction studies, and modified Mosher method. All 37 compounds were evaluated for the inhibition of LPS-induced nitric oxide (NO) production in RAW264.7 macrophages, and most of isolates significantly inhibited the NO production with IC₅₀ values in the range of 3.5-20 μM. Besides, results obtained in our studies provided a structure-activity relationship that would be used to design anti-inflammatory agents in the future.     

Disposable Screen‐Printed Edge Band Ultramicroelectrodes for Use as Nitric Oxide Gas Sensor in Designing an Easily Applicable Method for Real Sample Analysis of Nitrite with Superior Selectivity and Sensitivity

We report here an easily applicable method for the quantification of nitrite (NO₂^?) in real samples. This approach simplified the two steps of sample preparation and detection into a 2‐in‐1 single step process. Samples were digested in sulfuric acid and the as‐generated nitric oxide (NO) was detected by an electrochemical sensor in the gas phase. It eliminated almost all of the interferents in the solution phase and hence resulted in a highly selective determination of nitrite suitable for food samples with complicated matrix. We successfully demonstrated the determination of nitrite in sausage and vegetables and further validated the results with an AOAC official reference method.