一氧化氮及其合酶在哮喘发病机制中的作用

探讨一氧化氮及其合酶在哮喘发病机制中的作用。方法 采用哮喘豚鼠模型，将豚鼠分为４组；１．哮喘组，用１０％卵白蛋白腹腔注射１ｍｌ致敏，２周后用１％卵白蛋白超声雾化吸入致其哮喘发作．２；肾上腺皮质激素预防组；诱喘同哮喘组，在每次诱喘前腹腔滴注地塞米松０．５ｍｇ／ｋｇ。３．硝基精氨酸甲酯预防组；诱喘同哮喘组，每次诱喘产腹腔注射ＬＮＮＡ０．４ｍｇ／ｋｇ。４．正常对照组；用生理盐水代替诱喘剂。每组分别测定其     

梅毒患者血清一氧化氮和一氧化氮合酶水平测定

目的　检测梅毒螺旋体感染者血清中一氧化氮 (NO)和一氧化氮合酶 (NOS)的水平。方法　用分光光度法测定血清中NO水平和NOS活性 ,血清中NO3 和NO2 总量代表体内NO水平 ,NOS催化L 精氨酸和氧的反应生成NO的多少代表血清NOS活性。结果　梅毒患者NO浓度为 115± 36 3nmol/L ,NOS活性为 35 8± 7 3U/ml,二者均远远高于正常对照组。结论　梅毒螺旋体的感染引起患者体内NO水平和NOS活性升高 ,NO在梅毒感染中可能发挥重要的作用。     

动脉中的雌激素受体与一氧化氮合酶活性的关系

目的 :探讨动脉壁中雌激素受体在雌激素调控一氧化氮合酶 (NOS)活性中的作用。方法 :用放射配体结合分析技术检测大鼠主动脉中雌激素受体的含量。离体主动脉条药物孵育法观察雌激素和受体拮抗剂tamoxifen对NOS活性的影响。结果 :1 雌性大鼠主动脉中存在雌激素受体。 2 1nmol17β 雌二醇作用 8h能使大鼠主动脉NOS的活性显著增强 (P <0 0 1)。 3 雌激素受体拮抗剂tamoxifen能显著抑制雌激素的上述作用 (P <0 0 1)。结论 :17β 雌二醇对血管NOS活性的影响由动脉壁中雌激素受体介导 ,该作用可能是雌激素降低血管阻力、抑制动脉粥样硬化作用的重要机理之一。     

胃食管反流病患者食管NOS表达及血清NO含量变化的临床意义

目的探讨一氧化氮(NO)在胃食管反流病(GERD)发病机制中的作用.方法应用PC polygraf HR高分辨多通道测压系统检测GERD患者的食管下段括约肌压力(LESP)、食管下段括约肌长度(LESL)及食管远端蠕动幅度等动力参数;应用Digitrapper MK Ⅲ动态食管PH监测仪检测其24小时食管内PH各项参数;应用NADPH-d组化染色观察食管一氧化氮合酶(NOS)表达;应用硝酸还原酶法测定血清NO含量.结果GERD患者的LESP及LESL显著低于对照组(P＜0.01);前者的食管下段蠕动幅度明显低于后者(P＜0.01);前者的食管内24小时PH值明显高于后者;患者食管粘膜NOS呈强阳性反应;其血清NO含量也显著高于对照组.结论内源性NO可能参与GERD的致病机理.     

大鼠同种异位心脏移植术后血清NO及心肌组织NOS活性的观察

目的　研究内源性一氧化氮（ＮＯ）与心脏移植急性排斥反应的关系。方法　本研究以大鼠同种异位心脏移植为研究对象，观察了术后３、５、７ 天的血清ＮＯ 水平以及心肌组织一氧化氮合成酶（ＮＯＳ）的活性。结果　在急性排斥反应发生的早期开始血清ＮＯ 水平就已显著升高（术后３、５、７ 天皆为Ｐ ＜ ０．０１）；心肌组织ＮＯＳ活性亦显著高于对照组（术后３ 天Ｐ ＜ ０．０５，术后５ 天Ｐ＜ ０．０１，术后７ 天Ｐ ＜ ０．０５）。结论　血清ＮＯ 水平的检测对于心脏移植急性排斥反应的发生可能具有早期的辅助诊断意义。     

老年大鼠大脑组织一氧化氮、一氧化氮合酶的变化及神经细胞凋亡研究

目的研究一氧化氮(NO)、一氧化氮合酶(NOS)在老年大鼠大脑中的变化及其与神经细胞凋亡的关系. 方法选用5月龄大鼠和30月龄大鼠,利用Griess反应和高压液相技术间接测量大脑NO水平和NOS活性;免疫组化和原位杂交技术分别检测神经元NOS(nNOS)蛋白质水平和nNOS、bcl-2基因水平;末端转移酶标记法原位检测大脑神经细胞凋亡状况. 结果老年大鼠大脑组织NO水平和nNOS活性分别是(2.61±0.10)μmol*L-1和(398.22±21.62)fmol*mg-1*min-1,显著高于青年大鼠的(1.54±0.15)μmol*L-1和(234.38±16.24)fmol*mg-1*min-1.老年大鼠大脑nNOS的基因水平和蛋白表达水平均升高,抗凋亡基因bcl-2水平降低.在老年大鼠大脑质皮检测到散在的凋亡细胞. 结论老年大鼠大脑组织NO水平升高是由于nNOS活性升高所致.nNOS活性的增高部分是由其基因和蛋白水平来决定的.老年大鼠大脑组织NO异常升高可能是导致神经组织损伤进而凋亡的原因之一.     

幽门螺杆菌阳性胃炎患者胃粘膜-氧化氮合酶活力变化的意义

目的探讨幽门螺杆菌(Hp)感染时胃粘膜内一氧化氮合酶(NOS)活性和一氧化氮(NO)含量与细胞凋亡改变的意义.方法选择慢性活动性胃炎病人27例,其中Hp阳性者15例,Hp阴性者12例正常对照组10例.应用生物化学方法和切口末端标记法(Tunel)检测胃粘膜组织中一氧化氮产物N0-2水平、NOS活性及细胞凋亡指数.结果Hp感染时,胃粘膜NOS活性、NO-2水平及细胞凋亡指数明显升高,较Hp阴性组差异显著(P＜0.01),胃炎积分数与胃粘膜组织中NOS活性和NO-2水平呈明显正相关(r=0.66和0.84,P＜0.01).当根除Hp后,胃粘膜组织NOS活性,NO-2水平及细胞凋亡指数则显著降低,细胞凋亡指数与NOS活性和N0-2水平呈明显正相关(r=0.68和0.79,P＜0.01).结论Hp感染时可引起胃粘膜组织NOS活化,NO过量产生,细胞凋亡增加,这从又一方面说明Hp感染在胃腺癌发病机制中作用.     

脑梗死患者血清一氧化氮和一氧化氮合酶水平与脑血管反应性的关系

目的探讨脑梗死患者血清中一氧化氮(N0)和一氧化氮合酶(NOS)水平的变化对脑血管反应性(CVR)的影响。方法采用前瞻性病例对照研究,脑梗死组为发病2周内的颈内动脉系统脑梗死患者(193例),对照组为无脑梗死的体检者(103例)。对两组分别使用Griess重氮化反应法和酶标法,进行静脉血NO产物浓度及NOS活性检测;采用经颅多普勒超声结合屏气试验获取屏气指数(BHI)以评价CVR。结果脑梗死组和对照组的BHI分别为1.0±0.4和1.4±0.5,NO产物浓度中位数分别为6.04(3.83～11.49)、6.89(4.64～12.43)μmol/L,NOS活性分别为(3.0±1.5)、(3.2±1.5)U/ml。脑梗死组BHI及NO产物浓度均低于对照组(均P<0.05),BHI与NO产物浓度呈正相关(r=0.39,P=0.000),与NOS活性无相关性(r=0.168,P=0.454)。两组NOS活性差异无统计学意义(P=0.517)。结论脑梗死患者的CVR降低,与NO含量减少有一定相关性,但尚不能确定CVR与NOS活性的关系。NO可能是参与调节CVR的因素之一。     

阿托伐他汀对冠心病患者血清一氧化氮及一氧化氮合酶含量的影响

目的　观察阿托伐他汀对冠心病患者血清一氧化氮 (NO)及一氧化氮合酶 (NOS)含量水平的影响。方法　对用阿托伐他汀治疗的 79例冠心病患者依据是否合并高胆固醇血症分为两组 ,对其治疗前后血清 NO及 NOS含量水平进行对比分析。结果　不论是否合并高胆固醇血症的冠心病 ,阿托伐他汀均可升高其血清 NO及 NOS水平。结论　阿托伐他汀可通过调脂治疗抑制脂质的过氧化反应 ,保护血管内皮功能 ,但其保护内皮功能的作用不受患者是否存在高脂血症的影响 ,改善内皮功能 ,对冠心病的防治具有重要意义。     

一氧化氮及一氧化氮合酶在低氧性肺动脉高压中的研究进展

一氧化氮可调节肺血管张力,维持肺血管正常结构和肺循环的低阻力状态,在低氧性肺动脉高压的发生机制中起重要作用.由于一氧化氮具有独特的理化性质和生物学活性,因此目前研究主要集中在对其合成的关键酶一氧化氮合酶.下面就一氧化氮、一氧化氮合酶在低氧性肺动脉高压发病中的作用机制及临床应用的研究作一简单综述.     

吸烟对前列腺增生患者勃起功能及一氧化氮合酶和一氧化氮的影响

目的 探讨吸烟对良性前列腺增生(BPH)患者勃起功能及阴茎海绵体内血浆中一氧化氮(N0)含量及一氧化氮合酶(NOS)活性的影响.方法 选择90例BPH患者,吸烟BPH组51例,不吸烟BPH组39例.另选取体检健康男性40例为正常对照组.采用勃起功能国际问卷表(IIEF-5)对受试者进行调查,分别取阴茎海绵体内血液,采用硝酸还原酶法和分光光度比色法测定血浆中NO含量及NOS活性.结果 与正常对照组比较,吸烟BPH组及不吸烟组勃起功能障碍(ED)发生率明显增高(P＜0.05),IIEF-5评分、NO含量及NOS活性明显减少(P＜0.05).与不吸烟BPH组比较,吸烟BPH组ED发生率明显增高(P＜0.05),IIEF-5评分、NO含量及NOS活性明显减少(P＜0.05).吸烟组IIEF-5评分、NO含量及NOS活性与烟龄及烟量均呈高度负相关(P＜0.01).结论 BPH患者ED发生率较高,阴茎海绵体内血浆中NOS活性降低、NO含量下降可能是BPH致ED的原因之一,吸烟与ED的发生密切相关.     

Effect of homocysteine on the l-arginine/nitric oxide synthase/nitric oxide pathway in human platelets

Recent evidence indicates that chronic hyperhomocysteinemia is an independent risk factor for the development of atherosclerosis, thrombosis, and other cardiovascular diseases. This may be secondary to impaired fibrinolysis, or increased platelet reactivity. l-Arginine/nitric oxide synthase/nitric oxide (NO) plays an important role in the regulation of platelet function. The present study was undertaken to determine the effect of homocysteine (HCY) on the l-arginine/NO pathway of human platelets. Washed human platelets were incubated in the presence or absence of HCY for 2 h at 37°C followed by a measurement of indices of the l-arginine/NO pathway. HCY caused a concentration-dependent reduction in the platelet up-take of l-[³H]arginine. HCY also caused a concentration-dependent decrease in nitrite production concurrent with a decrease in cyclic guanosine monophosphate, whereas NO synthase activity of the platelets, measured as conversion of l-[³H]arginine to l-[³H]citrulline, remained unchanged on incubation with HCY. These observations indicate that the l-arginine/NO pathway is involved in the mechanism responsible for the effects of HCY on platelets by diminishing NO production through decreased uptake of l-arginine. Received: June 14, 2001 / Accepted: September 28, 2001     

硝酸甘油治疗大鼠骨质疏松症血清NO、NOS的变化

目的初步探讨用硝酸甘油治疗骨质疏松症(OP)及其与一氧化氮(NO)、一氧化氮合酶(NOS)的关系。方法将40只6月龄雌性大鼠随机分成假手术组(15只)和OP模型组(25只),其中OP模型组去卵巢造成骨质疏松模型,从其中随机选5只大鼠测定血清NO、NOS的变化,并与5只假手术组大鼠比较。剩余OP模型组大鼠随机分为OP对照组(10只)与硝酸甘油治疗组(10只),硝酸甘油治疗组经硝酸甘油治疗骨密度升高后,测其血清NO、NOS的变化,并与OP对照组及假手术组比较。结果OP模型组血清NO、NOS低于假手术组(P<0.01,P<0.05)。硝酸甘油治疗组大鼠骨密度升高后,其血清NO、NOS高于OP对照组(P<0.01,P<0.05),而与假手术组差异无显著意义(P>0.05)。结论NO、NOS参与了骨质疏松症的病理生理过程,硝酸甘油治疗骨质疏松症可能与NO、NOS有关。     

不同年龄大鼠组织NO含量和NOS活性的变化与衰老之间的关系

目的探讨组织一氧化氮（ＮＯ）含量与一氧化氮合酶（ＮＯＳ）活性的变化规律,揭示其与衰老的关系。方法采用铜离子活化镉还原法、硫代巴比妥酸染色法和血红蛋白氧化测定组织ＮＯ、丙二醛（ＭＤＡ）含量和ＮＯＳ的活性。结果与青年鼠组（４－５月龄相比,老年鼠组（２０－２２月龄）心脑肾组织ＮＯ降低差异显著性（Ｐ〈０．０１）,而中年鼠组（９－１０月龄）仅肾组织ＮＯ含量降低有显著性差异（Ｐ〈０．０５）。中年鼠组比较,老年     

肝病患者一氧化氮合酶表达异常及其临床意义

目的 探讨肝病患者抗氧化能力及一氧化氮合酶（NOS） 表达的临床价值。方法 收集26例急性肝炎（AH）、36例慢性肝炎（CH）、13例肝炎后肝硬化（LC）和23例原发性肝癌（HCC）患者的血清,分别检测其总抗氧化能力（TAO）、NOS浓度及一氧化氮（NO）水平,分析它们在肝脏疾病中的改变机制。结果 患者血清TAO在AH、CH中异常率为80％,在LC和HCC为50％;血清中NOS活性在肝病患者中的异常率在70％ 左右;NO水平在AH、CH和LC中异常率为70％,HCC组为48％。AH组、CH组TAO平均水平明显高于对照组,但LC和HCC组的差异不明显;肝病患者NO和NOS平均浓度显著高于对照组,但HCC患者NOS和NO平均浓度均低于AH、CH和LC组患者。结论 肝病患者血清NOS水平与NO浓度呈高度正相关,NO增加可能 对肝细胞起保护作用。     

内皮型一氧化氮合酶在早期糖尿病大鼠肾组织中表达的定量研究

目的探讨早期糖尿病大鼠肾组织内N0含量变化与一氧化氮合酶（eNOS）表达之间的关系。方法健康雄性SD大鼠60只随机分成糖尿病模型（DM）组和正常对照（NC）组,每组30只。检测两组大鼠的生化指标,检测肾皮质内NO的含量用亚硝酸还原酶法,肾皮质eNOS的含量用Western blot法。结果与同期NC组比较,（1）第1、2、4周DM组大鼠血糖显著升高（P〈0．01）;（2）DM组肾组织内NO含量在第1周时下降（3．52±0．45VS4．23±0．38）,P〈0．01;第2、4周时显著升高（P〈0．01）,第4周时升高最为明显（9．82±0．54VS4．02±0．32）,P〈0．01;（3）Western blot分析显示eNOS含量在第1周时下降,第2～4周时逐渐升高。结论早期糖尿病大鼠肾组织内NO含量逐渐升高,eNOS逐渐增多,提示在糖尿病早期肾组织内N0含量升高主要由eNOS增加引起。     

HbA<Subscript>1c</Subscript> levels and erythrocyte transport functions in complication-free type 1 diabetic children and adolescents

Higher erythrocyte sodium-lithium countertransport activity (SLC) is implicated in the development of diabetic nephropathy. Altered glucose homeostasis and genetic susceptibility are claimed to play a role in the elevation of SLC. We aimed to test whether metabolic control or the genetic variants of G protein beta 3 (Gb3) subunits determine SLC and other erythrocyte transport activities in complication-free stage of type 1 diabetes. A total of 96 complication-free type 1 diabetic children and adolescents were enrolled. SLC, Na⁺/K⁺-ATPase (NAK) and Ca²⁺-ATPase (CA) were measured by functional assays in erythrocytes. Gb3-C825T polymorphism was determined by PCR-RFLP. Results were related to HbA_1c and were compared to those of 97 healthy controls. SLC activity was higher in diabetics (387±146 vs. 280±65 mmol/RBC · hour) and correlated with HbA_1c levels (y=0.004x+6.42, r=0.33, n=96, p<0.01). NAK and CA activities were unaltered. The prevalence of ⁸²⁵T allele was similar in the patient and control groups (0.34 vs 0.37) and no differences in enzyme activities were observed between the ⁸²⁵T allele-positive and negative subjects. Although metabolic control correlated with SLC, other membrane functions were not affected. Therefore we hypothesize that the relationship between advanced glycation and SLC elevation is not causative. Rather, a genetic susceptibility for the coexistence of poor metabolic control and higher SLC is more likely. However, the presence of Gb3-C825T variant is not likely to be a risk factor for SLC-elevation and altered metabolic control diabetes. Received: 4 December 2001 / Accepted in revised form: 28 August 2002 Correspondence to B. Vásárhelyi     

Gene transfer of endothelial nitric oxide synthase alters endothelium-dependent relaxations in aortas from diabetic rabbits

Aims/hypothesis. Cardiovascular disease is the leading cause of death in diabetes mellitus. Abnormal endothelium-dependent relaxation is observed both in humans and in animal models of diabetes mellitus and decreased bioavailability of nitric oxide (NO) is thought to be involved in this defect. Therefore, the aim of this study was to test whether adenovirus-mediated gene transfer of endothelial nitric oxide synthase (eNOS) alters vascular reactivity of diabetic vessels.¶Methods. Vascular reactivity was first assessed in thoracic aortas and carotid arteries from nine alloxan-induced diabetic (plasma glucose, 26.5 ± 1.2 mmol/l; HbA_{1 c}, 6.4 ± 0.3 %) and nine control rabbits (plasma glucose, 11.1 ± 1.3 mmol/l; HbA_{1 c}, 2.1 ± 0.1 %). Vascular reactivity was next examined in thoracic aortas of diabetic animals after ex vivo transduction with replication-deficient adenovirus encoding gene for eNOS (AdeNOS) or β-galactosidase (Adβ gal).¶Results. After 10 weeks of hyperglycaemia, endothelium-dependent relaxation to acetylcholine was impaired in diabetic aorta, but was normal in carotid arteries from diabetic rabbits. In contrast, responses of both vessels to calcium ionophore and nitric oxide donor were normal. Histochemical staining for β-galactosidase and immunohistochemistry for eNOS showed transgene expression in the endothelium and adventitia in Adβ gal and AdeNOS transduced vessels, respectively. During submaximum contractions with phenylephrine, relaxations to low concentrations of acetylcholine (3 × 10^–8 to 10^–7 mol/l) were augmented in AdeNOS transduced diabetic vessels.¶Conclusion/interpretation. These findings suggest that adenovirus-mediated gene transfer of eNOS to diabetic aorta alters vascular reactivity. [Diabetologia (2000) 43: 340–347]     

Reversal of inducible nitric oxide synthase uncoupling unmasks tolerance to ischemia/reperfusion injury in the diabetic rat heart

The diabetic heart is known to be susceptible to ischemia/reperfusion (I/R) injury by increased oxidative stress. Although oxidative stress upregulates inducible nitric oxide (iNOS), the role of iNOS in I/R injury in the diabetic heart has been poorly understood. Because iNOS-derived nitric oxide (NO) plays a crucial role in cardioprotection against I/R injury, we hypothesized that inhibition of iNOS uncoupling would restore tolerance to I/R injury in the diabetic heart. The present study demonstrated that iNOS-derived superoxide generation was reduced, and that the NO bioavailability was increased, by treatment with the NOS-cofactor, tetrahydrobiopterin (BH4), before I/R in the hearts isolated from diabetic rats. This was associated with a reduction of infarct size and improvement of left ventricular (LV) function after I/R. The cardioprotective effect of BH4 was abrogated by treatment with a thiol reducing agent dithiothreitol (DTT), but not a NO-sensitive guanylyl cyclase inhibitor ODQ, suggesting that iNOS-derived NO-mediated cardioprotection occurs through protein S-nitrosylation but not cGMP-dependent signaling in the diabetic heart. Indeed, protein S-nitrosylation was increased by treatment with BH4 in the diabetic heart and was inhibited by DTT. These results suggest that the inhibition of iNOS uncoupling unmasks tolerance to I/R injury through enhanced protein S-nitrosylation in the diabetic rat heart.