前列环素与门静脉高压症高动力循环的关系

目的　探讨前列环素 (PGI2 )和一氧化氮 (NO)在门静脉高压症高血流动力循环中的作用。　方法　 66只雄性SD大鼠随机分成 :肝内型门静脉高压症组 (IHPH组 )、肝前型门静脉高压症组 (PHPH组 )和假手术组 (SO组 )。模型制备 1周后再随机分为 3个亚组 ,即对照组、一氧化氮合酶抑制剂L NNA组、消炎痛组。用药 1周后测定股动脉血浆 6 酮 前列腺素F1α(6 keto PGF1α)和NO2 - /NO3- 浓度 ,应用同位素微球技术行血流动力学研究 ,并对NO、PGI2 水平与血流动力学参数行Pearson相关分析。　结果　 (1 )在基础状态下 ,血浆 6 keto PGF1α浓度 ,IHPH鼠 [(1 1 2 3 85± 1 53 64)pg/ml]和PHPH鼠 [(891 88± 83 1 1 )pg/ml]均显著地高于SO鼠 [(72 5 53± 1 0 5 54)pg/ml] ,P <0 0 5 ;血浆NO2 - /NO3- 浓度 ,IHPH鼠 [(73 34± 4 31 ) μmol/L]和PHPH鼠 [(75 2 1± 6 89) μmol/L]均显著高于SO鼠[(58 79± 8 47) μmol/L] ,P <0 0 5。 (2 )与对照组比较 ,L NNA与消炎痛均显著地降低IHPH与PHPH 2组鼠血浆 6 keto PGF1α和NO2 - /NO3- 的浓度 ,P <0 0 5 ;降低IHPH、PHPH 2组鼠的心脏指数 (CI)、门静脉压力 (FPP)和门静脉血流量 (PVI) ,P <0 0 5 ;显著地增高这 2组鼠的平均动脉压 (MAP)、总外周血管阻力 (TPR)和内脏血     

门静脉高压症病人肠道通透性、NO和内毒素的研究

目的　观察门静脉高压症病人的门静脉压力、肠道通透性、NO和内毒素水平 ;并分析它们之间的相互关系。方法　门静脉高压症病人 2 0例 ,分别检测肠道通透性、门静脉压力和外周血中NO和内毒素浓度。另有 2 0位健康志愿者作对照。结果　门静脉高压症病人较健康志愿者的肠道通透性 (0 132± 0 110vs 0 0 32± 0 0 18,P <0 0 1) ,外周血的NO浓度 (38 77± 13 71vs 2 1 77±3 0 1μmol/L ,P <0 0 0 1)和内毒素浓度 (0 5 7± 0 18vs 0 11± 0 0 5EU/ml,P <0 0 0 1)均非常明显的升高。研究还发现门静脉压力和这三者均有显著相关性 (r >0 45 ,P <0 0 5 ) ,另外肠道通透性与内毒素浓度 (r=0 5 2 9,P <0 0 5 )也存在相关性 ,而与NO浓度则无相关性 ;内毒素和NO之间没有发现相关性。结论　研究表明门静脉高压症病人肠道通透性、NO和内毒素水平显著升高。门静脉压力和这三者的显著相关说明门静脉压力升高是导致肠道通透性升高的直接因素 ,而内毒素和NO的升高维持了门静脉的高动力循环。     

内皮素-1 mRNA在肝肺综合征大鼠肺组织中表达的研究

目的　研究内皮素 1(ET 1)及其mRNA在肝肺综合征 (HPS)大鼠肺组织中的表达。方法　 3 2只雄性SD大鼠随机分 4组 :肝前型门静脉高压症组 (PHPH)、肝内型门静脉高压症组(IHPH)、门腔端侧分流组 (PCS)和手术对照组 (SO) ,每组 8只。各组均行动脉血气分析 ;应用硝酸还原酶法和放射免疫法测定肺组织中NO2 -/NO3-及ET 1含量 ;应用原位杂交和图像分析 ,检测肺泡毛细血管内皮细胞、肺泡动脉内皮细胞和支气管上皮细胞中ET 1mRNA的表达强度。　结果　 ( 1)动脉血气分析 :动脉氧分压IHPH组大鼠 [( 73 85± 6 5 1)mmHg]较PHPH组 [( 97 3 9± 1 3 3 )mmHg]、PCS组 [( 95 2 3± 2 2 2 )mmHg]和SO组 [( 99 0 5± 0 75 )mmHg]显著下降 (P <0 0 5 ) ;肺泡 动脉氧压力梯度 :IHPH组大鼠 [( 3 4 5 3± 2 3 2 )mmHg]较PHPH组 [( 4 98± 1 69)mmHg]、PCS组 [( 6 5 1± 2 0 4 )mmHg]和SO组 [( 3 2 3± 0 81)mmHg]显著增大 (P <0 0 5 ) ,并伴轻度呼吸性碱中毒。 ( 2 )肺组织中NO2 -/NO3-含量 ( μmol/g蛋白 ) :IHPH组大鼠 ( 19 78± 5 3 3 ) μmol/g显著高于PHPH组 ( 13 2 1± 3 99)μmol/g、PCS组 ( 13 89± 3 16) μmol/g和SO组大鼠 ( 8 71± 1 68) μmol/g。肺组织中ET 1含量 (pg/g) :IHPH组大鼠 ( 195 1     

一氧化氮降低肝硬化门静脉高压症血管收缩反应性的实验研究

目的 探讨NO在肝硬化门静脉高压症血管收缩反应中发挥作用的机制,特别是NO与RhoA/ROCK通路间的相互作用机制.方法 分别测定正常大鼠(正常对照组,5只)、CCl4诱导的肝硬化门静脉高压症大鼠(实验对照组,6只)和经L-NAME处理的门静脉高压症大鼠(L-NAME处理组,6只)外周血和肠系膜动脉NO含量;利用血管灌流系统测定上述3组大鼠肠系膜微动脉对去甲肾上腺素的反应;Westernblot分别检测3组大鼠肠系膜动脉NO-cGMP-PKG通路和RhoA/ROCK相关蛋白表达水平的变化.多组间均数比较采用单因素方差分析,两两比较采用LSD-t检验,肠系膜微动脉对去甲肾上腺素反应性的变化通过量-效曲线表示,运用非线性回归法,计算出EC50值.结果 (1)正常对照组、实验对照组和L-NAME处理组大鼠平均门静脉压力分别为(6.2±0.9)mm Hg(1mm Hg =0.133 kPa)、(13.9±1.7)mm Hg和(16.6±1.3)mm Hg,3组比较,差异有统计学意义(F=94.4,P＜0.05).(2)正常对照组、实验对照组和L-NAME处理组大鼠平均血清NO浓度分别为(43±5)μmol/L、(82±16) μmol/L和(45±9)μmol/L,3组比较,差异有统计学意义(F =24.77,P＜0.05);L-NAME处理组大鼠平均NO浓度明显低于实验对照组(P＜0.05).(3)正常对照组、实验对照组和L-NAME处理组大鼠肠系膜动脉平均NO含量分别为(236±41) μmol/g、(407±82) μmol/g和(216 ±42) μmol/g,3组比较,差异有统计学意义(F =20.29,P＜0.05);L-NAME处理组大鼠肠系膜动脉平均NO含量明显低于实验对照组(P＜0.05).(4)与实验对照组大鼠比较,L-NAME处理组大鼠的离体肠系膜微动脉对去甲肾上腺素剂量反应曲线左移,但未达到正常对照组大鼠反应曲线水平,正常对照组、实验对照组和L-NAME处理组大鼠EC50分别为6.458×10-7 mol、9.546×10-7 mol和7.494×10-7 mol,L-NAME处理组与其余两组比较,差异有统计学意义(=2.726,3.112,P＜0.05).(5)与正常对照组比较,实验对照组大鼠肠系膜动脉eNOS蛋白和p-VASP蛋白表达水平明显增高(P＜0.05),但L-NAME处理组eNOS和p-VASP蛋白表达水平显著降低,但仍高于正常对照组(P＜0.05).3组大鼠肠系膜动脉PKG-1、ROCK-1和p-moesin蛋白表达水平无明显变化(P＞0.05).(6)去甲肾上腺素刺激后,正常对照组和L-NAME处理组大鼠肠系膜动脉ROCK-1的活性显著上升,而实验对照组无变化.结论 CCl4致肝硬化门静脉高压症大鼠肠系膜动脉NO含量增高,影响缩血管物质诱导ROCK激活;L-NAME降低肠系膜动脉壁内NO的含量,改善了RhoA/ROCK信号通路传递障碍,促使缩血管物质诱导ROCK激活,但不影响ROCK蛋白表达水平的变化.     

肝硬变门静脉高压症患者血浆尾加压素Ⅱ水平的变化

目的研究肝硬变门静脉高压症(PHT)患者外周血浆尾加压素Ⅱ(UⅡ)水平的变化以及与肝功能的关系。方法用放射免疫学方法分别测定21例健康对照者和29例PHT患者(按肝功能Child-Pugh分级将病例分为A,B,C 3组)外周血浆中UⅡ的含量,并进行相互比较。结果PHT患者外周血浆UⅡ水平[(1.821±0.020)pg/ml]低于对照组[(1.973±0.016)pg/ml],其差异有统计学意义(t=-3.190,P<0.01),且随着肝功能的恶化,UⅡ水平逐步降低(r=-0.401,P<0.05)。结论UⅡ与肝硬化门静脉高压症的发生发展可能存在一定的联系,其内在机制尚待进一步研究。     

NOSTRIN在无精子症患者睾丸组织中的表达

目的:通过测定无精子症患者睾丸组织中内皮型一氧化氮合酶运输介导物(NOSTRIN)和内皮型一氧化氮合酶(eNOS)的表达,探讨其与无精子症发病的相关性。方法:采用免疫组化法检测17例特发性无精子症患者(病例组)和10例正常男性(正常组)睾丸组织中NOSTRIN的定位和定量表达;RT-PCR检测睾丸组织中NOSTRINmRNA的表达;分光光度法测定睾丸组织中eNOS的活性;应用硝酸还原酶法测定睾丸组织上清液中NO代谢产物亚硝酸基/亚硝基(NO2-/NO3-)水平。结果:NOSTRIN在睾丸组织中表达于生精细胞、支持细胞以及血管内皮细胞,NOSTRIN在特发性无精子症患者睾丸中的表达水平显著低于正常男性;病例组患者睾丸组织中NOSTRINmRNA呈弱表达(0.312±0.076),明显低于正常组(0.793±0.082,P<0.01);病例组患者睾丸组织eNOS活性[(33.727±3.58)U/mg]与正常组[(17.69±3.84)U/mg]比较显著增高(P<0.01);病例组患者睾丸中NO2-/NO3-水平为[(48.56±8.49)μmol/L],与正常组[(25.37±9.61)μmol/L]比较显著升高(P<0.01);病例组睾丸组织中NOSTRIN表达水平与eNOS活性呈负相关(r=-0.57,P<0.01),与NO代谢产物NO2-/NO3-同样呈负相关(r=-0.61,P<0.01)。结论:无精子症患者睾丸组织中NOSTRIN表达水平降低,eNOS活性增强,NO-/NO-水平升高,这可能与无精子症的发生有着相关性。     

甲状旁腺切除术对血液透析患者合并继发性甲状旁腺功能亢进骨代谢及骨密度的影响

目的 观察甲状旁腺切除术(parathyroidectomy,PTX)对继发性甲状旁腺功能亢进(secondary hyperparathyroidism,SHPT)的维持性血液透析患者骨代谢及骨密度(BMD)的影响.方法 26例SHPT患者行PTX.术前及术后1、3、6、12、18、24个月时常规检测血钙、血磷、血清碱性磷酸酶,化学发光法检测血清全段甲状旁腺素(intact parathyroid,iPTH)、骨钙素(OC)、Ⅰ型前胶原氨基末端前肽(PINP)、β胶原蛋白(β-C TX),术前及术后24个月时双能X线法测定腰椎、股骨颈、骨盆各部位骨密度,观察患者甲状旁腺切除术前、术后骨代谢指标及骨密度变化.结果 (1)与术前比较,血清OC水平[(104.49±25.42) μg/L比(695.46±355.62) μg/L,P＜ 0.01]、PINP水平[(248.36±159.38) μg/L比(809.28±283.50) μg/L,P＜0.01]于手术3个月后明显降低,β-CTX水平于手术1个月后明显降低[(1.60±0.64) μg/L比(3.37±1.34) μg/L,P＜0.01].(2)与术前比较,术后24个月时腰椎BMD[(0.88±0.23) g/cm2比(0.78±0.23) g/cm2,P＜0.01]、股骨颈BMD[(0.96±0.19) g/cm2比(0.84±0.24) g/cm2,P＜ 0.01]及腰椎Z评分[(-1.24±0.55)比(-1.66±0.24),P＜0.01]、股骨颈Z评分[(-1.51±0.72)比(-1.93±0.40),P＜0.01]均升高.(3)相关分析显示,术前血清iPTH水平与⊿腰椎Z评分(r=0.584,P=0.002)、⊿股骨颈Z评分(r=0.400,P=0.043)呈正相关,术前血清OC水平与⊿腰椎Z评分(r=0.651,P＜0.001)、⊿股骨颈Z评分(r=0.509,P=0.008)呈正相关.结论 PTX术可以降低患者升高的iPTH、OC、PINP及β-CTX水平,增加骨密度,同时改善多项生化指标,提高患者生活质量.     

重症急性胰腺炎患者血和腹水一氧化氮的动态变化

目的　研究诱生型一氧化氮合酶 (iNOS)活性在重症急性胰腺炎 (SAP)患者中的变化。方法　动态观察 30例重症急性胰腺炎患者发病后血性腹水和外周血一氧化氮 (NO)代谢产物NO2 - /NO3- 的变化。逆转录 聚合酶链反应 (RT PCR)检测外周血单个核细胞iNOSmRNA的变化。结果　SAP患者血性腹水NO2 - /NO3- 含量为 (385 .0± 92 .3) μmol/L与对照组 (41 .3± 1 9.5)μmol/L比较显著升高 (P <0 .0 0 1 )。起病后第 1、7、1 4天外周血NO2 - /NO3- 含量分别为(1 38.8±30 .2 ) μmol/L、(1 2 6 .4± 35 .4) μmol/L和 (77.8± 37.1 ) μmol/L ,随病情好转逐渐下降(P <0 .0 1 )。外周血单个核细胞iNOSmRNA表达在病情严重时显著增强。结论　iNOS活性增强产生过量NO参与重症急性胰腺炎全身病理生理的改变     

外源性腺苷三磷酸对移植胰腺再灌注损伤保护作用的实验研究

目的　探讨外源性三磷酸腺苷 (ATP)对大鼠移植胰腺再灌注损伤的作用及其机制。方法　应用同系大鼠异位全胰十二指肠移植模型 ,供体胰腺分别用EuroCollin液 (EC)或EC液添加ATP约 12～ 2 0ml(2～ 4℃ )进行低温灌注保存 6 0min ,光镜观察胰腺组织结构变化 ,放射自显影鉴定外源性ATP是否进入胰腺细胞内 ,高压液相色谱法 (HPLC)检测保存后移植物ATP和总腺苷核苷酸(TAN)。移植 2 4h后 ,检测血糖、血清中脂肪酶、淀粉酶 ,测定移植胰腺组织中髓过氧化酶 (MPO)活性 ,并进行组织学观察。结果　实验组保存的胰腺组织结构损伤明显轻于对照组。保存后实验组胰腺组织ATP和TAN水平 [(5 6 6± 0 37) μmol/ g ,(8 6 2± 0 88) μmol/g]明显高于对照组 [(2 82±0 2 4 ) μmol/ g ,(4 34± 0 4 1) μmol/ g],差异具有显著性 (P <0 0 5 )。放射自显影显示外源性 [α 3 2 P]ATP进入胰腺细胞内。移植胰腺早期功能指标检测 ,实验组血糖值 [(9 3± 2 2 )mmol/L]明显低于对照组 [(14 1± 2 9)mmol/L],实验组血清脂肪酶 [(139± 13)U/L]明显低于对照组 [(2 96± 2 5 )U/L],实验组胰腺组织MPO[(1 19± 0 16 )U/ g ]明显低于对照组 [(2 2 5± 0 2 8)U/ g],差异均具有显著意义 (P <0 0 5 )。结论　外源性ATP用于胰腺     

供体年龄对活体肾移植预后的影响

目的 探讨供体年龄对活体肾移植预后的影响.方法 回顾性分析2004年至2011年间在我院实施的活体亲属肾移植217例,按供体年龄或供受体年龄差异分组,随访并比较各组受者的血肌酐水平和术后并发症情况.结果 随着供体年龄的增长,受体移植术后血肌酐水平呈上升趋势.与供受体年龄差＜-5岁组比较,供体年龄差＞5岁组的Scr水平在1个月[(143.5±42.1) μmol/L比(114.4±30.4)μ mol/L]、3个月[(139.9±36.6) μmol/L比(110.6 ±33.3)μmol/L]、1年[(132.1±22.1)μmol/L比(105.5±35.9) μmol/L]及2年(132.0±45.4) μmol/L比(97.2±17.5) μmol/L]均增高,差异有统计学意义(均P＜0.05).与年轻供肾组(＜50岁)相比,老年供肾组(＞50岁)的急性排斥反应发生率(19.4％比9.7％)和慢性排斥反应发生率(9.7％比1.4％)也显著增高(均P＜ 0.05).术后人及肾的存活率比较差异无统计学意义.供受体年龄差异是术后2年Scr水平异常的独立危险因素(OR=5.010,P＜0.05).结论 供体年龄是肾移植预后的重要影响因素,老年供肾的疗效较差.     

门静脉高压症大鼠内毒素血症与一氧化氮变化

本研究拟通过测定门脉高压大鼠血浆内毒素和亚硝酸根/硝酸根离子(NO_2~-/NO_3~-)浓度,探讨一氧化氮(NO)在鼠门高压时产生是否过多及其可能机制.雌性SD大鼠分为三组:端侧门腔分流(PCS,n=10),门静脉部分缩窄引起的肝前型门高压(PHT,n=10)和手术对照组(Sham,n=8).模型制备后两周测定门脉压(FPP)并从腹主动脉采集血样,用于测定(1)血浆亚硝酸根/硝酸根离子浓度;(2)血浆内毒素浓度;(3)肝、肾功能.结果显示:血浆内毒素和NO_2~-/NO_3~-水平是PCS>PHT>Sham,且血浆内毒素与NO_2~-/NO_3~-之间呈密切正相关,提示门脉高压时因门体分流和肝功能减退导致血浆内毒素水平升高,刺激NO合成与释放增多.     

Hepatic and mesenteric nitric oxide synthase expression in a rat model of CCl(4)-induced cirrhosis

BACKGROUND: Cirrhosis and portal hypertension are frequently linked with changes in expression of nitric oxide synthase (NOS) and/or endotoxaemia. AIMS: This study tested the following hypothesis: that inducible (i)NOS activity is increased within the visceral circulation concurrently with decreased constitutive (c)NOS activity in the hepatic sinusoids and that the concentration of NO metabolites in portal blood is consequent on endotoxin concentration. MATERIALS AND METHODS: Plasma concentrations of (nitrite + nitrate) and endotoxin, together with hepatic and mesenteric NOS activity (arginine/citrulline method) and protein expression (histochemistry) plus portal and arterial blood pressure, were determined in rats made severely cirrhotic by intragastric CCl(4) over 14 weeks (n = 6) compared with age-matched controls (n = 5). The concentrations of [nitrite + nitrate] and endotoxin in portal plasma were also directly compared in rats made cirrhotic for a period of 8-14 weeks (n = 10). RESULTS: In rats with advanced cirrhosis, arterial [nitrite + nitrate] was 93.1 (22.4) micromol/L (mean, SEM) compared with 29.1 (6.1) micromol/L in controls (P < 0.05); portal plasma [NO(2)(-) + NO3(-)] was 127.1 (27.2) compared with 24.7 (4.7) micromol/L in controls (P < 0.05). Cirrhotic rats had higher endotoxin concentration in plasma compared with controls (systemic: 85.0 (24.5) versus 1.7 (0.2) EU/ml, P < 0.05; portal: 180.3 (47.9) versus 1.7 (0.2) EU/ml, P < 0.05). The same severely cirrhotic rats possessed decreased cNOS activity in liver (2.95 [0.40] versus 5.29 [0.85] pmol/min/g; P < 0.05) and increased iNOS activity in mesentery (4.83 [1.23] versus 1.47 [0.15] pmol/min/g; P < 0.05) compared with controls. Histochemical observations confirmed these findings. Rats given CCl(4) for a period of 8-14 weeks possessed high endotoxin concentration in portal plasma, with correspondingly high [nitrite + nitrate] (r(2) = 0.954; P < 0.001). CONCLUSIONS: An endotoxin-induced increase in mesenteric iNOS activity and a decrease in hepatic cNOS activity may account for, respectively, the hyperdynamic visceral circulation and the increased intrahepatic resistance of cirrhosis.     

Portal triad occlusion induces endotoxin tolerance: role of portal congestion

BACKGROUND: Portal triad occlusion (PTO) causes portal congestion and damages the intestinal mucosa, which is associated with portal endotoxemia. However, administration of a sublethal dose of endotoxin results in resistance to its toxic activities. We tested the hypothesis that portal congestion due to PTO induces endotoxin tolerance. MATERIALS AND METHODS: Rats were subjected to PTO for 15 min. In Group 1, male rats underwent laparotomy and, 48 h after the surgery, a lethal dose of Escherichia coli lipopolysaccharide was administered. In Group 2, rats were subjected to PTO for 15 min. Then a lethal dose of LPS was administered 48 h after surgery. Group 3 was treated the same as Group 2, except that PTO was performed with portosystemic shunt. Group 4 was also treated same as Group 2, except that rats received polymixin B and neomycin by gavage to eliminate intestinal luminal bacteria before PTO. Survival was examined after the administration of a lethal dose of LPS. Changes in plasma levels of cytokine are also measured after the administration of LPS. The portal endotoxin level in each group after PTO was measured. RESULTS: On survival test, only rats in Group 2 and Group 4 showed significantly higher survival rates. The portal endotoxin level was significantly elevated only in Group 2. The elevation of plasma cytokine levels (IL-6, TNF-alpha) and NO production (NO(2)(-)/NO(3)(-)) in Groups 2 and 4 were inhibited compare to those in Groups 1 and 3. CONCLUSIONS: PTO induced LPS tolerance possibly due to portal congestion and subsequent visceral congestion.     

Enhanced production of nitric oxide may be involved in acute hypotension during maintenance hemodialysis

To investigate the possible involvement of endogenous nitric oxide (NO) in acute hypotension during maintenance hemodialysis, we measured the plasma concentration of the nitrate anion NO3-, a stable metabolite of NO, in 19 patients undergoing hemodialysis. We analyzed heart rate variability to estimate the relationship between autonomic nervous activity and NO production, low-frequency/high-frequency components (L/H) as a parameter of cardiac sympathetic activity, and high-frequency power as a parameter of cardiac vagal activity. Six patients developed severe hypotension (a change in mean blood pressure during dialysis > or = 20 mm Hg), four patients developed mild hypotension (a change in mean blood pressure < or = 19 mm Hg and > or = 1 mm Hg), and nine patients did not develop hypotension. The plasma levels of NO3- before dialysis were markedly elevated in the severely hypotensive group compared with the patients who showed no hypotension (566+/-122 micromol/L v 133+/-38 micromol/L; P < 0.01), and this difference disappeared midhemodialysis and after hemodialysis. The plasma concentration of NO3- before dialysis was significantly associated with both the change in mean blood pressure during dialysis (r= -0.735; P = 0.003) and the mean blood pressure after dialysis (r = -0.675; P = 0.0015). The L/H ratio was inhibited before or after dialysis in the severely hypotensive group compared with the nonhypotensive group, and hypotension during dialysis was correlated with the inhibited L/H ratio before (r = 0.784; P = 0.001) or after (r = 0.822; P = 0.001) dialysis. Plasma NO3- concentrations were correlated with the L/H ratio before (r = -0.553; P = .014) or after (r = -0.546; P = 0.015) dialysis. These results suggest that inhibited sympathetic activity is one of the causes of acute hypotension during dialysis, and the enhanced production of NO is involved in this inhibition of the sympathetic activity in patients having a hypotensive episode during dialysis. The plasma concentration of NO3- before dialysis may be a predictor of the risk of hypotension during dialysis in patients with end-stage renal disease.     

Altered alanine plasma levels despite normalized hepatic alanine extraction in the long-term course after liver transplantation

BACKGROUND: The amino acid (AA) metabolism in cirrhosis is deranged, reflected by an altered plasma AA profile. Alanine is a unique AA with predominant production by muscle and the highest hepatic extraction rate. METHODS: We studied circulating levels and hepatic alanine extraction in 52 patients with advanced cirrhosis, 16 stable patients more than 6 months after orthotopic liver transplant (OLT), and 50 controls. In addition, hepatic hemodynamics (portal pressure, hepatic blood flow, and splanchnic percent indocyanine green extraction) and parameters of hepatic metabolism (splanchnic oxygen uptake and splanchnic glucose production) were assessed. RESULTS: Circulating alanine levels decreased independently of the clinical stage in cirrhosis (262+/-15 micromol/L vs. 330+/-14 micromol/L in controls, P<0.001) and decreased even further after OLT (209+/-10 micromol/L, P<0.001). Hepatic alanine extraction decreased dependently on the clinical stage in cirrhosis (59+/-7 micromol/min) and was normalized after OLT (100+/-10 micromol/min, P<0.001), indicating that decreased plasma alanine levels in OLT patients are the result of changes in extrahepatic metabolism. Hepatic alanine extraction correlated with splanchnic oxygen uptake (r=0.64, P<0.001) and hepatic glucose production (r=0.65, P<0.001). CONCLUSIONS: These results demonstrate that significant alterations in muscular AA metabolism persist even in the clinically stable long-term course after OLT when the hepatic AA metabolism is normalized.     

Impaired vasoreactivity despite an increase in plasma nitrite in patients with abdominal aortic aneurysms

OBJECTIVE: This investigation was designed to determine whether differences in vasoreactivity occur in patients with abdominal aortic aneurysms (AAAs) as compared with patients with peripheral arterial occlusive disease (PAOD) or individuals (controls) without known vascular disease. METHODS: Brachial artery vasoreactivity was assessed in a blinded fashion, after endothelium-dependent (ED) and endothelium-independent (EI) flow-mediated vasodilation, in age-matched, male patients with AAAs (n = 11) or PAOD (n = 9) or in controls (n = 10). There were no significant differences in prestudy systolic or diastolic blood pressure, body mass index, or antilipidemic medications among the groups studied. Exclusion criteria included diabetes and tobacco use within 3 months. Quantitative ultrasound scan measurements of brachial artery diameters were performed at rest and after either forearm ischemia (ED) or administration of 0.4 mg sublingual nitroglycerin (EI). Plasma nitric oxide (NO(X) = NO(2) + NO(3)) was measured with the Saville assay. Asymmetric dimethylarginine, an endogenous inhibitor of NO(X) synthase, was measured with liquid chromatography. RESULTS: Initial brachial artery diameters were not significantly different among the groups studied (4.85 +/- 0.18 mm for AAA group, 4.82 +/- 0.17 mm for PAOD group, 4.68 +/- 0.20 mm for controls). ED and EI vasodilation was significantly less (P =.02 and.03, respectively) in the AAA group (-1.71 +/- 1.52 and 8.33 +/- 1.13, respectively) when compared with the controls (2.96 +/- 1.04 and 13.88 +/- 2.16, respectively). However, plasma NO(X) was significantly increased (P =.01) in the AAA group (7.86 +/- 0.85 micromol/L) as compared with both controls (5.13 +/- 0.63 micromol/L) and PAOD (4.85 +/- 0.46 micromol/L). Asymmetric dimethylarginine levels were decreased in the AAA group (0.34 +/- 0.05 micromol/L) as compared with the PAOD group (0.46 +/- 0.09 micromol/L). No correlation existed between aneurysm size and ED or EI vasodilation or plasma NO(X). CONCLUSION: This study is the first to document a divergence between ED and EI vasoreactivity and systemic NO metabolites in patients with AAAs. It is speculated that a dysfunctional vessel wall response, rather than a lack of NO, may be important in the pathogenesis of AAAs.     

Early changes of endothelin,nitric oxide and arginine—vasopressin in patients with acute cerebral injury

OBJECTIVE: To investigate the early changes and clinical significance of plasma endothelin (ET), nitric oxide (NO) and arginine-vasopressin (AVP) in patients with acute moderate or severe cerebral injury. METHODS: The early (at 24 hours after injury) plasma concentrations of ET, NO and AVP were measured with radioimmunoassay and Green technique in 48 cases of acute moderate (GCS8 in 21 cases) cerebral injury (Group A), in 42 cases of non-cerebral injury (Group B) and in 38 normal individuals (Group C), respectively. RESULTS: The early plasma concentrations of ET (109.73 ng/L+/-12.61 ng/L), NO (92.82 micromol/L+/-18.21 micromol/L ) and AVP (49.78 ng/L+/-14.29 ng/L) in Group A were higher than those in Group B (67.90 ng/L+/-11.33 ng/L, 52.66 micromol/L+/-12.82 micromol/L and 29.93 ng/L+/-12.11 ng/L, respectively, P<0.01) and Group C (50.65 ng/L+/-17.12 ng/L, 36.12 micromol/L+/-2.16 micromol/L and 5.18 ng/L+/-4.18 ng/L, respectively, P<0.001 ). The amounts of ET, NO and AVP in patients with severe cerebral injury were 116.18 ng/L+/-18.12 ng/L, 108.19 micromol/L+/-13.28 micromol/L and 58.13 ng/L+/-16.78 ng/L, respectively, which were significantly higher than that of the patients with moderate cerebral injury (92.33 ng/L+/-16.32 ng/L, 76.38 micromol/L+/-12.71 micromol/L and 36.18 ng/L+/-12.13 ng/L respectively, P<0.01 ). The early levels of ET, NO and AVP in Group A were negatively related to the GCS scales. The amounts of ET, NO and AVP were 126.23 ng/L+/-15.23 ng/L, 118.18 micromol/L+/-10.12 micromol/L and 63.49 ng/L+/-14.36 ng/L respectively in patients with subdural hematoma, which were significantly higher than those in patients with epidural hematoma (81.13 ng/L+/-12.37 ng/L, 68.02 micromol/L+/-13.18 micromol/L and 45.63 ng/L+/-12.41 ng/L respectively, P<0.01). The plasma concentrations of ET, NO and AVP in stable duration (at 336 hours after injury) in Group A and Group B were similar to those in Group C. CONCLUSIONS: ET, NO and AVP were related to the pathophysiological process that occurs in the early stage of acute cerebral injury and the values of ET, NO and AVP correlate positively with the clinical manifestations. The changes of plasma ET, NO and AVP can be regarded as important indices to assess the severity of acute cerebral injury.     

Autocrine effects of nitric oxide on HCO(3)(-) transport by rat thick ascending limb

BACKGROUND: In vivo and in vitro studies have shown that nitric oxide (NO) is an important modulator of transport processes along the nephron. The thick ascending limb (TAL) plays a significant role in the urine-concentrating mechanism and in the maintenance of acid/base balance. METHODS: TALs from male Sprague-Dawley rats were isolated and perfused, and net bicarbonate flux (J(HCO3)(-) was determined. RESULTS: In perfused TALs, 0.5 mmol/L L-arginine (L-Arg), the substrate for NO synthase, significantly lowered J(HCO3)(-) from 35.4 +/- 4.6 to 23.2 +/- 2.9 pmol. mm(-1). min(-1), a decrease of 36.9 +/- 11.6% (P < 0.025). D-Arg (0.5 mmol/L) had no effect on J(HCO3)(-) (N = 7). In the presence of 5 mmol/L L-NAME, an NO synthase (NOS) inhibitor, the addition of L-Arg did not affect TAL J(HCO3)(-) (43.4 +/- 4.4 vs. 44.6 +/- 5.0 pmol. mm(-1). min(-1)). L-NAME alone (5 mmol/L) did not affect TAL J(HCO3)(-). After removing L-Arg from the bath, J(HCO3)(-) increased from 26.2 +/- 3.9 to 34.8 +/- 3.2 pmol. mm(-1). min(-1) (P < 0.01), indicating no cytotoxicity of NO. We next investigated the effect of cGMP analogues on TAL J(HCO3)(-). 8-Br-cGMP (50 micromol/L) and db-cGMP (50 micromol/L) significantly decreased J(HCO3)(-) by 26.3 +/- 9.1% and 35.1 +/- 11.6%, respectively. In the presence of cGMP (50 micromol/L), the addition of L-Arg had no effect on J(HCO3)(-). In the presence of KT-5823 (2 mircromol/L), a protein kinase G inhibitor, the addition of L-Arg did not change TAL J(HCO3)(-) (N = 5). CONCLUSIONS: We conclude that (1) endogenously produced NO inhibits TAL J(HCO3)(-) in an autocrine manner, (2) cGMP mediates all the effects of NO, and (3) this effect is mediated by protein kinase G activation.     

Management of massive and persistent ascites and/or hydrothorax after liver transplantation

PURPOSE: To describe the results of the treatment of eight liver transplantation (LT) patients subsequently developing large volumes of long-lasting ascites. PATIENTS AND METHODS: Between August 1996 and February 2003, 405 LTs were performed in 375 patients, eight (1.97%) of whom (six men and two women of mean age of 55.4 +/- 5.2 years) subsequently developed massive (> 500 mL/d) and persistent ascites and/or hydrothorax. All patients were HCV positive. The mean age of the liver donors was 66.8 +/- 21.9 years. All LTs were performed by replacement of the recipient retrohepatic vena cava. RESULTS: The eight patients displayed sinusoidal portal hypertension related to biopsy-proven recurrence of HCV infection. Mean wedged hepatic venous pressure was 14.9 +/- 5.1 mm Hg and mean portal vein/right atrial pressure gradient (PAPG) was 17.3 +/- 4.8 mm Hg. In two patients, the ascites appeared the day after LT; in the remaining six, ascites and/or hydrothorax appeared after 342.3 +/- 167.7 days. Seven patients with a mean PAPG of 18.4 +/- 3.9 mm Hg and a mean plasma/ascites albumin concentration gradient of 2.8 +/- 0.3 g/L were treated by means of a trans-jugular intrahepatic portosystemic shunt TIPS, and one (with a PAPG of 9 mm Hg and a plasma/ascites albumin concentration gradient of 1.38 g/L) by means of spleen arterial embolisation. After a mean follow-up of 558 +/- 147.2 days, the ascites and/or hydrothorax have resolved in five patients (62.5%), one (12.5%) has stable ascites not requiring paracentesis, and two (25%) have died of multiorgan failure. CONCLUSIONS: These data suggest the efficacy of the aggressive treatment of massive and persistent ascites and/or hydrothorax.     

Asymmetrical dimethylarginine plasma concentrations are related to basal nitric oxide release but not endothelium-dependent vasodilation of resistance arteries in peritoneal dialysis patients

Vascular dysfunction in chronic renal failure may be linked to reduced nitric oxide (NO) bioactivity and increased circulating concentrations of the endogenous NO synthase inhibitor asymmetrical dimethyl L-arginine (ADMA). The association between ADMA and basal endothelial NO release and endothelium-dependent vasodilation in resistance arteries of chronic renal failure patients is unknown. Forearm blood flow responses to the endothelium-dependent vasodilator acetylcholine, the endothelium-independent vasodilator nitroglycerine, and the endothelium-dependent vasoconstrictor N(G)-monomethyl-L-arginine (L-NMMA) were assessed in 37 peritoneal dialysis patients. L-arginine and ADMA plasma concentrations were measured by HPLC. ADMA (mean +/- SEM: 0.68 +/- 0.02 micromol/L) was associated with basal forearm blood flow (r = -0.33; P < 0.05) and L-NMMA induced vasoconstriction (r = -0.55; P < 0.0005), but not with dilator effects of acetylcholine or nitroglycerine. L-arginine (68 +/- 3 micromol/L) tended to correlate with acetylcholine-induced vasodilation (r = 0.32; P = 0.05) but was not associated with other parameters. ADMA is related to basal but not to acetylcholine-stimulated NO bioactivity in patients on peritoneal dialysis. Impaired endothelium-dependent vasodilation found in chronic renal failure is not explained by elevated circulating NO synthase inhibitors in renal failure.