S-nitrosylation/activation of COX-2 mediates NMDA neurotoxicity

Glutamate/N-methyl-d-aspartate (NMDA) receptor-mediated neurotoxicity involves cyclooxygenase (COX)-2. We demonstrate that this neurotoxicity reflects activation of COX-2 by S-nitrosylation after selective binding of neuronal nitric oxide synthase (nNOS) to COX-2. nNOS, via its PDZ domain, binds COX-2 with the generated NO S-nitrosylating and activating the enzyme. Selective disruption of nNOS-COX-2 binding prevents NMDA neurotoxicity.     

人胃癌组织中一氧化氮合酶的表达

目的探讨NOS与胃癌的关系.方法用NADPH-d组织化学法测定了正常胃组织、癌旁组织和癌组织中一氧化氮合酶(NOS)表达水平.结果正常胃组织中粘膜上皮细胞、各种有分泌功能的细胞及肌层神经纤维中均有NOS表达,测一个视野NOS阳性细胞的平均灰度,正常胃组织为112、癌旁组织为120、胃癌组织为145.各组间差异有显著意义.表明正常胃组织NOS活性最高,胃癌组织NOS活性最低.结论①正常胃组织有广泛的NOS分布,提示NO对维持正常胃功能具有重要作用;②胃粘膜细胞癌变过程中,NOS活性明显降低,提示NOS活性与胃粘膜细胞癌变有高度相关性.     

Nitric oxide: not just a negative inotrope

Nitric oxide (NO) appears to play a role in modulating cardiac function in both health and disease. Early studies in isolated rodent cardiac myocytes demonstrated a depressant effect of NO supplied by NO donors (exogenous) as well as NO generated within myocytes (endogenous). There is increasing evidence for a functional NO generating system within the human myocardium, which appears upregulated in certain disease states. Induction of the high output nitric oxide synthase isoform (iNOS) has been demonstrated in the failing myocardium, though its functional significance remains unproven. More recently published data have contradicted the notion that NO acts solely as a negative inotrope demonstrating positive inotropy in both isolated rodent and human ventricular myocytes in response to a range of NO donors. Different NO donors have different NO release kinetics and generate a range of NO species (NO., NO+ and NO-) which may interact at a number of subcellular targets. The observed response of any cardiac preparation to an NO donor represents the net effect of activation of different effector targets and may explain the contradictory reported effects of NO. To realise the therapeutic potential of NO will require specific targeting at a subcellular level.     

Expression of inducible nitric oxide synthase in human gastric cancer

INTRODUCTIONInduciblenitricoxidesynthase(iNOS)isanenzymethatcatalyzestheformationofnitric0xide(N0)fromL-arginine.iNOSexpressionandactivityresultsintheproduction0fhighlevelsofNO[1].ThegenerationofphysiologicallevelsofNOisimp0rtantformucosalfunctionanditalsoexertsacytoprotectiveeffectonthegastr0intestinalmucosa.However,increasediNOSexpressionhasbeenobservedinpatientswithchronicinflammatorydiseasesofthegastr0intestinaltract,suchasulcerativec0litis[2'3],andgastritis['Jandithasbeenspecul…     

诱导型一氧化氮合酶在心肌缺血/再灌注损伤中的研究进展

采用溶栓疗法、动脉搭桥术、冠状动脉血管成形术等技术,使缺血组织和器官重新恢复血流,挽救了众多危急重病人的生命,然而,缺血器官及组织在恢复血流的同时,均伴随着缺血/再灌注损伤,是目前临床上亟待解决的问题。在对心血管疾病的研究过程中,随着心肌保护研究的不断深入,如何减轻心肌缺血/再灌注损伤成为心肌保护问题的关键。越来越多的研究表明,心肌缺血/再灌注损伤与诱导型一氧化氮合酶表达过量一氧化氮紧密相关。研究表明,诱导型一氧化氮合酶既有心肌保护作用,也有促心肌损伤作用,而通过对诱导型一氧化氮合酶抑制剂的应用,有望减轻心肌损伤的进展,保护损伤心肌。     

内皮型一氧化氮合酶基因G894T多态性与原发性高血压的相关关系

目的　探讨内皮型一氧化氮合酶 (eNOS)基因G894T多态性与中国汉族人原发性高血压 (EH)的相关性。方法　 (1)采用多聚酶链式反应结合限制性内切酶片段长度多态分析方法检测310例健康人和 15 1例高血压患者的eNOS基因G894T多态性 ,(2 )硝酸还原酶法测定空腹血清一氧化氮代谢物 (NOx)水平 ,用放射免疫法测定内皮素 (ET)的水平。结果　 (1)EH组GT TT基因型和T等位基因频率显著高于对照组 (P <0 0 5 ) ;(2 )高血压患者中T等位基因携带者的收缩压 [(15 0 5± 13 6 )mmHg]、舒张压 [(10 0 0± 8 5 )mmHg]和脉压 (116 8± 7 8)mmHg均高于GG基因型携带者 (14 5 0± 12 2 ,97 4± 8 0 ,114 0± 7 5 )mmHg ,且有显著性差异 ,(P <0 0 5 )。 (3)EH组GT TT基因型空腹血清NOx[(6 9 7± 2 7 0 ) μmol/L]、NOx/ET比 (1 0 1± 0 5 6 )明显低于GG基因型 (78 5± 32 5 ) μmol/L (1 4 7± 1 5 1) ,而GT TT基因型 (83 2 5± 39 74 ) pg/mLET水平明显高于GG基因型 (72 9± 33 8)pg/mL。 结论　eNOS基因G894T多态性的T等位基因与中国汉族人EH的发生相关 ,T等位基因携带者可能通过减少内皮NO的释放参与EH发病。     

孤啡肽在原发性高血压时的改变及其降压机制初探

目的观察原发性高血压患者血浆孤啡肽水平的改变及孤啡肽对血管内皮舒张因子（ＥＤＲＦ／ＮＯ）的影响，初步探讨孤啡肽舒张血管，降低血压的可能机制。方法应用放射免疫测定法测定原发性高血压患者（３２例）血浆孤啡肽水平并以正常成年人（１９例）作对照。大鼠主动脉条组织孵育液中亚硝酸盐的含量可反映一氧化氮（ＮＯ）的产生量，采用微盘测定法测定，用张新波等建立的ＮＯ合酶测定改良法检查ＮＯＳ活性。结果ＥＨ患者血浆孤啡肽水平明显高于对照组（１５．４７±２．１４ｎｇ／Ｌｖｓ８．８３±５．６８ｎｇ／Ｌ，Ｐ＜０．０５），且随高血压程度分期的加重，孤啡肽水平增加越明显。孤啡肽能明显刺激大鼠主动脉条组织ＮＯ产生量和提高ＮＯＳ活性，随剂量的增加，此作用更加明显（Ｐ＜０．０５）。结论推测孤啡肽可能为一种存在于外周血液中与血压调节有关的新型血管活性多肽，其与心血管疾病的关系有待进一步深入研究。     

原发性肝癌血管形成的免疫组化和形态学研究

目的研究原发性肝癌血管形成及血管起源。方法用病理及CD34、UEA-1、Collagen Ⅳ免疫组化的方法对21例肝癌及癌旁组织中血管形成进行原位检测和观察。结果阳性反应可见血管星棕色或棕黄色条带。癌旁组织血窦内皮细胞CD34及UEA-1染色阴性,炎症组织内的血管染色阳性。部分肿瘤血管与癌旁组织血管不相连;部分肿瘤血管与癌旁组织血管相连。Collagen Ⅳ在肝癌组织中有较强的表达,癌旁组织中表达很弱,但在门脉区炎症组织内表达可较强。结论CD34、UEA-1、Collagen Ⅳ染色与肿瘤血管形成有关,部分肝癌血管可能起源于毛细血管化的癌旁肝血窦。     

肝癌组织中一氧化氮合酶及其基因表达的研究

目的研究肝癌组织中一氧化氮合酶(iNOS)及其基因表达与肝癌发生发展的关系。方法用免疫组化和原位杂交的方法对21例肝癌及癌旁组织中的诱导型一氯化氮合酶(iNOS)及其基因表达进行原位检测和观察。结果:NOS 阳性反应物质呈黄色或棕黄色,位于细胞浆中。非癌殖织(肉眼观距癌组织边缘>1.5)多呈阴性或弥漫弱阳性,但部分非癌组织中可见 iNOS 呈阳性的细胞呈点状分布;癌旁组织多呈阳性,提示 iNOS 表达与肝组织癌变有关。癌组织核心多呈阴性或弥漫弱阳性,但分化中和差的癌组织核心也分别有一例 NOS 呈强阳性;周边癌组织呈局灶阳性,侵入纤维组织中的弥敢癌细胞星强阳性,提示 NOS 的表达与肝癌组织的侵润能力有关。肝癌组织 iNOSmRNA 阳性细胞的分布与 iN-OS 蛋白的表达基本相似。结论 iNOS 蛋白及其基因表达与肝组织癌变及肝癌侵润能力有关。     

The impact of estrogen and L-arginine on serum NO and eNOS expression in aorta of aged rats

Background Cardiovascular diseases (CVD) are less prevalent in postmenopausal women received estrogen replacement therapy (ERT) than those who did not receive ERT.Previous study has shown that the increase of nitric oxide (NO) synthesis is one of the cardioprotective effects of estrogen.This study investigated the effects of estrogen and L-arginine (L-Arg) on serum NO concentrations and the possible regulatory role in endothelial nitric oxide synthase (eNOS) expression in aortas of aged rats.Methods Fifty aged female wistar rats (18-20 months) were randomly divided into five groups (n=10):Sham group (sham operated,0.9 % NaCl 10 μg every three day for 4 months),OVX group (ovariectomized,0.9 % NaCl 10 μg i.m every three day for 4 months),OVE group (ovariectomized + 17β-estradiol 10 μg i.m every three day for 4 months),OVE + L-Arg group (ovariectomized + 17β-estradiol 10ug i.m every three day + 2.25 % L-Arg contained in drinking water every day for 4 months) and L-Arg group (ovariectomized + 2.25 % L-Arg contained in drinking water every day for 4 months).NO concentration and the expression of eNOS mRNA in aorta were measured after 4 months.Results Serum NO synthesis did not alter after ovariectomized (P=0.362),but were increased in OVE group,L-Arg group and OVE + L-Arg group compared with OVX group (P < 0.05,P < 0.05,P < 0.01,respectively).NO concentration also increased in OVE + L-Arg group when compared with OVE group (P < 0.05) or L-Arg group (P < 0.05).There was no significant difference in eNOS mRNA expression in aortas of aged rats between sham,OVX,OVE,OVE + L-Arg and L-Arg group (F=0.550,P=0.700).Conclusions Estrogen treatment and L-Arg supplementation increase serum NO synthesis,but do not upregulate eNOS mRNA expression in aortas of aged rats.     

Nitrotyrosine and NO synthases in infants with respiratory failure: influence of inhaled NO

Inhaled nitric oxide (NO) is a selective vasodilator in pulmonary hypertension. However, the safety of inhaled NO (iNO) has not been established. Using an immunohistochemical technique, we studied the expression of NO synthase (NOS) isoforms NOS1, NOS2, NOS3, and nitrotyrosine, the marker of toxic NO-superoxide pathway, in lung specimens from autopsies. Twelve infants dying with respiratory failure had iNO up to 60 parts per million for 0.1-15 days. Twelve control infants were matched in pairs on the basis of the diagnosis, number of gestational days at birth, age at death, and whether extracorporeal perfusion was required. In addition, 5 infants who died of SIDS or nonpulmonary trauma (healthy lungs) were compared to 8 age-matched cases with respiratory failure. Immunostaining was graded by the intensity of the color deposit and the frequency in specific cells stained. Inhaled NO tended to increase NOS2 expression in bronchiolar epithelium and adjacent tissue. There were no other differences in the distribution of nitrotyrosine or NOS isoforms between iNO-treated infants and the control group with respiratory failure. All NOS isoforms were evident in the lungs studied. In severe respiratory failure, nitrotyrosine was mostly detectable in the bronchiolar epithelium and alveolar exudates, whereas in healthy lungs those sites did not contain nitrotyrosine. The alveolar tissue of infants with progressive respiratory may be affected by the NO-superoxide pathway. However, inhalation of NO was not associated with a detectable increase in oxidant stress.     

Effect of nitric oxide synthase inhibition on Schistosoma japonicum egg-induced granuloma formation in the mouse liver

Nitric oxide (NO) plays diverse roles in a variety of pathological processes. We investigated the role of NO in Schistosoma japonicum egg-induced granuloma formation in a mouse hepatic model. Immunohistological analysis revealed that there is the most intense and extensive inducible nitric oxide (iNOS) expression 2 weeks after egg implantation, and thereafter it decreased considerably with time. Treatment with nitric oxide synthase inhibitors, NIL (L-N6- (iminoethyl)-lysine) or N(omega)-nitro-L-arginine methyl ester (L-NAME), resulted in two different types of unusual granulomas at 2 weeks. One type showed suppressed fibrosis, while another showed foreign body-type multinuclear cell formation which frequently appeared particularly when 50 microg/ml NIL was given. At 3 weeks following treatment, fibrotic granulomas with scanty peripheral cellularity was obvious. However, there were no apparent changes after this period (at 4 weeks). Cytokine analysis in NIL-treated mice showed a significant increase of IL-4 and IL-13 production at 2 weeks. These findings indicated that nitric oxide contributes to granuloma development during the early stages, probably through the regulation of Th2 cytokine production.     

Cytochrome c oxidase regulates endogenous nitric oxide availability in respiring cells: a possible explanation for hypoxic vasodilation

One of the many routes proposed for the cellular inactivation of endogenous nitric oxide (NO) is by the cytochrome c oxidase of the mitochondrial respiratory chain. We have studied this possibility in human embryonic kidney cells engineered to generate controlled amounts of NO. We have used visible light spectroscopy to monitor continuously the redox state of cytochrome c oxidase in an oxygen-tight chamber, at the same time as which we measure cell respiration and the concentrations of oxygen and NO. Pharmacological manipulation of cytochrome c oxidase indicates that this enzyme, when it is in turnover and in its oxidized state, inactivates physiological amounts of NO, thus regulating its intra- and extracellular concentrations. This inactivation is prevented by blocking the enzyme with inhibitors, including NO. Furthermore, when cells generating low concentrations of NO respire toward hypoxia, the redox state of cytochrome c oxidase changes from oxidized to reduced, leading to a decrease in NO inactivation. The resultant increase in NO concentration could explain hypoxic vasodilation.     

Beneficial Effects of Nitric Oxide on Cardiac Diastolic Function: 'The Flip Side of the Coin'

Modulation by NO of systolic myocardial function received widespread attention but most studies focused on potential negative inotropic properties of NO. The very original observations on the effects of NO on myocardial contraction already provided evidence that NO modified myocardial contractile performance mainly through a relaxation-hastening effect (i.e. earlier onset of relaxation) and through an increase in myocardial distensibility. The present review discusses the relaxation hastening and distensibility-increasing effects of NO in experimental preparations, in the normal human heart, in left ventricular hypertrophy of aortic stenosis, in the human allograft and in dilated nonischemic cardiomyopathy. This diastolic flip side of the myocardial effects of NO appears to be beneficial especially for patients who are dependent on the LV Frank-Starling response to maintain cardiac output.     

NO与肝癌形成

目的研究一氧化氮(NO)在肝癌发生发展的作用。方法用免疫组化的方法对21例肝癌及癌旁组织中的3种一氧化氮合酶(NOS)及血管内皮细胞生长因子(VEGF)的表达进行原位检测和观察,结果紧邻癌细胞的肝硬化组织或慢性肝炎组织iNOS呈强阳性,远离癌组织的肝硬化组织或慢性肝炎组织多呈阴性或弥漫弱阳性;iNOS在周边癌组织及侵入纤维组织中的癌细胞呈阳性,癌组织核心多呈阴性或弥漫弱阳性。VEGF、nNOS的分布与iNOS相似。eNOS主要分布在肝癌细胞小血管壁内皮及其肌层组织。结论 NOS表达与肝组织癌变及肝癌侵润能力有关,与癌组织获得血管形成和转移表型有关。     

洛汀新对原发性高血压患者NOS活性及NO的影响

目的:探讨血管紧张素转换酶抑制剂洛汀新对原发性高血压（EH）患者的降压作用及其对NO和NOS水平的影响。方法:采用每日1次洛汀新10 mg治疗EH患者（21例）8周,观察治疗前、后血压和血小板（Pt）NO水平及NOS活性的变化。结果:EH患者Pt的NOS活性和NO水平显著低于正常对照组（14例）（P<0.01）。经洛汀新治疗后EH患者的血压显著降低（P<0.01）,Pt的NO产生量及NOS活性显著升高（P<0.01）。结论:洛汀新可降低血压、调节血小板NOS的活性和NO分泌量。     

内皮型一氧化氮合酶基因多态性与原发性高血压的相关关系

目的 探讨内皮型一氧化氮合酶(eNOS)基因27bp数目可变的串联重复序列(VNTR)多态性与中国汉族人原发性高血压(EH)的相关性。方法 (1)聚合酶链反应(PCR)及琼脂糖凝胶电泳检测334例EH患者的基因型，同时进行基因测序。(2)硝酸还原酶法测定空腹血清一氧化氮代谢物(NOx)水平，用放射免疫法测定内皮素(ET)的水平。结果(1) EH组aa ab基因型和a等位基因频率显著高于对照组；(2)EH组内ab ab基因型空腹血清NOx、NOx／ET比明显低于bb基因型。结论 eNOS基因27bpVNTR的a等位基因与中国汉族人EH的发生相关，a等位基因携带者可能通过减少内皮：NO的释放、损害内皮功能参与EH发病。     

心肌成纤维细胞NOS-NO系统活性的变化及其与AVP的关系

目的 :探讨无干预和血管升压素 （AVP）干预条件下 ,心肌成纤维细胞 （CFs）的一氧化氮合酶—氧化氮 （NOS-NO）系统活性的变化。方法 :胰酶消化法分离、培养新生 SD大鼠 CFs,采用硝酸还原酶法和分光光度法观察无干预和 AVP干预条件下 ,不同培养时间对 CFs的 NOS- NO系统活性的影响。结果 :1无干预条件下 ,CFs的 NO含量和 NOS活性随培养时间延长而增高 ,其中 36 h（4 2± 5 μmol· L- 1 ,37± 5 U· m L- 1 ）显著高于 6 h（14± 3μmol·L- 1 ,10± 4U· m L- 1 ）以及 12 h（2 1± 3μm ol· L- 1 ,15± 3U· m L- 1 ） （均 P<0 .0 5 ）。 2 AVP干预条件下 ,CFs的NO含量和 NOS活性也随培养时间延长而增高 ,其中 2 4h（6 5± 6 μmol· L- 1 ,70± 4U· m L- 1 ） ,36 h（6 2± 1μm ol· L- 1 ,6 9± 6 U· m L- 1 ）都显著高于 6 h （34± 4μmol· L- 1 ,36 +2 U· m L- 1 ）以及 12 h的 （4 5± 4μmol· L- 1 ,45± 1U· m L- 1 ） （均 P<0 .0 5 ）。 3AVP干预条件下 CFs的 NO含量和 NOS活性均较无干预条件下显著增高 ,且 NO含量随 NOS活性增高而增高 ,二者呈显著正相关 （无干预条件下 r=0 .837,P<0 .0 1;AVP干预条件下 r=0 .936 ,P<0 .0 1）。结论 :AVP提高 CFs的 NOS- NO系统活性 ,CFs的 NOS- NO系统活性与培养和 AVP?