小鼠十二指肠运动中NO对NA作用的影响及机制

目的观察去甲肾上腺素(noradrenaline ,NA)对离体小鼠十二指肠肌条收缩幅度及一氧化氮(nitricoxide ,NO)对NA作用的影响;探讨NO和NA之间的关系及影响机制。方法用器官浴槽孵育离体小鼠十二指肠肌条,以肌张力收缩幅度抑制比为指标观察NA对肌条收缩幅度及NO对NA作用的影响。结果NA对肌条的收缩幅度有明显的抑制作用,在浓度1.2×10 -4～1.2×10 -8mol/L范围内,呈剂量-效应关系,其中1.2×10 -8mol/L组与对照组之间无显著性差异(P >0 .0 5 )。L Arg对肌条的收缩幅度有明显的抑制作用,在浓度2×10 -2 ～2×10 -6mol/L范围内,呈剂量-效应关系。除2×10 -6mol/L组外,其余各浓度的L Arg与对照组均有显著性差异(P <0 .0 0 1)。用无反应剂量2×10 -6和2×10 -3 mol/L的L Arg孵育标本后加入NA ,浓度为1.2×10 -5,1.2×10 -6,1.2×10 -7,1.2×10 -8mol/L的NA对肌条收缩幅度的抑制作用明显增强,与单独NA组的作用相比差异有显著性(P <0 .0 0 1) ;而1.2×10 -4mol/LNA组与单独NA组的作用相比差异无显著性(P >0 .0 5 )。分别用一氧化氮合酶(NOS)的抑制剂L NNA、可溶性鸟苷酸环化酶(sGC)抑制剂ODQ、α肾上腺素能受体阻断剂酚妥拉明(phentolamine)均使NA对肌条收缩幅度抑制效应明显减弱,与对照组比较有显著性差异(P <0 .0 0     

前列腺素缺乏条件下促胃动力药胃复安对大鼠胃粘膜的损伤作用与可能机制

目的探讨前列腺素(prostaglandin,PG)缺乏条件下促胃动力药胃复安对大鼠胃粘膜的损伤作用与可能机制。方法 PG缺乏状态由5mg/kg吲哚美辛诱导;雄性SD大鼠随机分组:对照组;胃复安两组(30mg/kg,60mg/kg);吲哚美辛两组(5mg/kg,25mg/kg);吲哚美辛5mg/kg合用胃复安三组(10mg/kg,30mg/kg,60mg/kg);阿托品组(阿托品-吲哚美辛5mg/kg+胃复安60mg/kg),禁食24h后,生理盐水或吲哚美辛灌胃,30min后皮下注射胃复安或生理盐水,阿托品灌胃前10min皮下注射,4h后取血,处死大鼠取胃行损伤测定:放免法测血浆内皮素(Endothelin ET-1);生化法测—氧化氮(nitric oxide NO)、丙二醛(Malondialdhyde MDA)、谷胱甘肽过氧化酶(Glutathioneperoxidase GSH-Px)含量。结果吲哚美辛合用胃复安三组胃粘膜均有明显损伤,ET-1、MDA升高(p<0.05.p<0.01),NO、GSH-Px下降(p<0.05,p<0.01);吲哚美辛25ng/kg组损伤严重,ET-1、MDA升高(p<0.01),NO、GSH-Px下降(p<0.01,P<0.05);胃复安60mg/kg胃有轻微损伤,各指标无显著变化;其余各组未见明显损伤及指标变化。结论(1)PG缺乏条件下促胃动力药胃复安可引起胃黏膜出血性损伤,可能与ET-1升高、NO下降致胃黏膜微循环紊乱有关.MDA升高,GSH-Px减少可能为损伤后的继发反应结果,加剧了黏膜损伤。(32)胃动力有潜在的引起胃黏膜损伤的能力,PG缺乏增加了胃黏膜对胃高动力的敏感性。提示临床上非甾体抗炎药(NSAIDs)服用者应慎用胃动力药,因为合用可能形成或加剧胃黏膜损伤。     

Off-line exhaled nitric oxide measurements in children

The concentration of exhaled nitric oxide (eNO) is a useful marker of asthmatic bronchial inflammation. eNO can now be measured away from the laboratory (off-line), even in children. Short exhalation maneuvers (8 sec) and small samples (1 L) of exhaled gas are probably sufficient in children, but more information is needed about the effect of different measurement conditions. As a preliminary step before conducting epidemiological studies in schoolchildren, we investigated the effects of expiratory flow, dead space, and expiratory time on eNO concentrations collected in 1-L mylar collection bags. We studied 101 cooperative subjects (62 males) aged 5-18 years (30 healthy volunteers, 51 asthmatics, and 20 children with various other respiratory diseases) in our pulmonary function laboratory. On-line and off-line eNO were compared in a single session, and analyzed with a Sievers NOA 280 nitric oxide analyzer. For both methods of collecting expired gas, subjects did a single exhalation without breath-holding against an expiratory pressure 10 cm H(2)O. We investigated the effects of expiratory flow, dead space, and exhalation time on eNO; we also compared on-line and off-line eNO measurements, and the repeatability of both techniques at a given flow rate. Expiratory flows of 58 mL/sec provided more reproducible data than lower flows (coefficient of repeatability 1.1 ppb for 58 mL/sec vs. 2.8 for 27 mL/sec vs. 5.7 for 18 mL/sec). eNO concentrations were about 25% higher in off-line than in on-line recordings if the initial 250 mL of exhaled gas were not eliminated, and 37% higher if exhalation lasted longer (16 sec vs. 8 sec). Eliminating 250 mL of dead space and shortening the filling time to 8 sec yielded off-line eNO values close to those on-line (geometric mean off-line eNO 14.4 ppb, 95% confidence interval: 12.2-17.0) vs. on-line eNO 13.8 ppb (95% confidence interval: 11.6-16.5). On-line and off-line results were highly correlated (r = 0.996, P = 0.000) and had similar coefficients of variation (on-line eNO 2.6%, off-line 2.8%). Neither agreement nor repeatability of eNO measurements were affected by disease status or baseline FEV(1) (% predicted values). Once standardized, the off-line eNO technique using 1-L gas collection bags will provide results similar to those recorded on-line.     

Alterations in the endothelial G-protein coupled receptor pathway in epicardial arteries and subendocardial arterioles in compensated left ventricular hypertrophy

The present study was designed to compare alterations of endothelium-dependent vasorelaxation in coronary epicardial arteries and subendocardial arterioles occurring in left ventricular hypertrophy (LVH) secondary to 60 days of aortic banding in a porcine model. Development of LVH was documented by echocardiogram and the endothelial function of subendocardial and epicardial vessels was studied by constructing concentration-response curves in a pressure myograph and standard organ chambers, respectively. 5-HT induced relaxations were reduced (p < 0.05) in both vessel types isolated from pigs with LVH. Dilations of subendocardial arterioles and epicardial vessels to UK14304 were depressed by LVH. In the presence of Nω-nitro-L-arginine (L-NNA), EDHF solely accounts for BK-induced relaxations; it fully compensates for the loss of NO in arterioles, but only partially in epicardial arteries isolated from LVH swine. Endothelium-independent relaxations induced by SNP were not altered in both vessel types from the LVH group. In a porcine model of LVH secondary to 60 days of aortic banding, the associated coronary endothelial dysfunction preferentially involves Gi-protein mediated relaxations in arterioles and arteries but also affects Gq-protein mediated relaxations in epicardial coronary arteries. *These authors equally contributed to this work.     

前列腺素EI对人脐静脉内皮细胞中NO和eNOS的影响

目的探讨前列腺素EI(prostaglandin EI,PGEI)对内皮细胞一氧化氮(NO)表达和内皮型一氧化氮合酶(eNOS)活性的影响。方法以人脐静脉内皮细胞(HUVEC)为实验对象,检测不同浓度PGEI作用不同时间后,细胞培养上清液和细胞中NO水平的变化,以及细胞eNOS活性的改变。结果(1)随着PGEI浓度的升高,eNOS的活性和NO的含量均逐渐增加(P<0.05);(2)短时间PGEI的干预对eNOS和NO的影响均不明显,24h后细胞中eNOS活性明显升高(P<0.05),NO的含量自12h起随时间延长而增加(P<0.05);(3)用不同PGEI浓度预处理,使TNF-α对eNOS活动的抑制作用减弱。结论PGEI可能通过诱导eNOS的表达,促进NO的释放,且可以重新激活被TNF-α抑制的eNOS活性。     

Dynamic physiological and molecular changes in gastric ulcer healing achieved by melatonin and its precursor L-tryptophan in rats

Abstract:  Following induction of gastric ulcer in rats by serosal application of acetic acid, local mucosal necrosis ensues accompanied by a reduction in mucosal microcirculation and by almost immediate expression of inducible nitric oxide (NO) synthase (iNOS) and proinflammatory cytokines. Daily application of melatonin (20 mg/kg) or l -tryptophan (100 mg/kg) accelerates ulcer healing by affecting the cyclooxygenase-2 (COX-2)–prostaglandin (PG) system with excessive production of protective PG, especially in later period of ulcer healing. Furthermore, expression of hypoxia inducible factor, vascular-endothelial growth factor, an activation of cNOS–NO system and the stimulation of sensory nerves with the expression and release of calcitonin gene related peptide (CGRP) appear to aid the restoration of mucosal repair and microcirculation in the ulcer bed. The enhanced expression of the melatonin MT₂ receptors (MT₂-R) combined with overexpression of key enzymes involved in biosynthesis of melatonin such as N -acetyltransferase and hydroxyindole- O -methyltransferase contribute to the acceleration of ulcer healing by this indole. Melatonin-induced acceleration of ulcer healing is also mediated by release of gastrin and ghrelin, the most potent stimulants of gastric mucosal cell proliferation and mucosal repair. These sequential steps in ulcer healing accelerated by melatonin can be interfered with by the blockade of MT₂R, COX-2/PG and cNOS/NO systems, and by reduction in the inflammatory iNOS/NO system. Thus, melatonin and its precursor l -tryptophan, trigger the cascade of molecular events leading to the functional improvement in ulcer healing.     

检测血清与腹水血管内皮生长因子对消化系恶性肿瘤的诊断价值

目的　探讨检测血清与腹水血管内皮生长因子 (VEGF)对消化系恶性肿瘤的诊断及良、恶性腹水鉴别诊断的价值。方法　采用酶联免疫吸附法 (ELISA法 )检测 5 8例消化系疾病患者血清与腹水VEGF含量。结果　消化系肿瘤患者血清与腹水中VEGF含量明显高于良性疾病患者 (P <0 .0 1)。联合检测血清与腹水VEGF含量 ,其诊断肿瘤性腹水的敏感性较单独检测腹水VEGF有明显提高 (P <0 .0 5 )。结论　血清与腹水VEGF检测有助于消化系恶性肿瘤的临床诊断和良恶性腹水的鉴别诊断     

The polyol pathway and glucose 6-phosphate in human endothelial cells cultured in high glucose concentrations

Summary In an attempt to identify the mechanisms underlying the ill effects of high glucose previously described in cultured human endothelial cells, we have investigated in these cells the activity of the polyol pathway and accumulation of glucose 6-phosphate, a powerful agent of non-enzymatic glycosylation. Sorbitol accumulation varied among different batches of cells (primary cultures). In presence of 5 mmol/l glucose the cellular sorbitol content ranged from 0.04 to 0.12 nmol/10⁶ cells. When cells were exposed to 20 mmol/l glucose the sorbitol content increased by 2- to 3-fold to concentrations of 0.08–0.38 nmol/10⁶ cells (p<0.01). Addition to the culture medium of 100 mol/l Sorbinil, an inhibitor of aldose reductase, resulted in a substantial inhibition of sorbitol accumulation throughout the 14 days in culture, but the degree of inhibition varied inversely with the duration of cell exposure to high glucose (70% inhibition in cells exposed to high glucose and Sorbinil for 1–3 days versus 14% inhibition in cells exposed for 14 days, p<0.01). Sorbinil treatment failed to improve even slightly the abnormalities in cellular replication induced by high glucose. The cellular content of glucose 6-phosphate was augmented 3-fold by exposure to 20 mmol/l glucose (p<0.001). In conjunction with other studies these results indicate that in this model the polyol pathway is not an osmotically or metabolically important mechanism of glucotoxicity, and that the inhibitory activity of Sorbinil on the polyol pathway of human tissues may be a function of their length of exposure to hyperglycaemia. The consequences of intracellular accumulation of glucose 6-phosphate await investigation.     

NO、NOS在大鼠实验性结肠炎中的动态变化及意义

目的　观察大鼠实验性结肠炎发生发展过程中一氧化氮 (nitricoxide ,NO)、一氧化氮合酶 (nitricoxidesynthase ,NOS)的动态变化 ,了解NO、NOS同大鼠实验性结肠炎的关系。方法　采用 2 ,4 二硝基氯苯 (2 ,4 dinitrochlorobenzene ,DNCB)诱发大鼠实验性结肠炎模型 ;Wistar雄性大鼠 70只 ,检测造模前 (Ⅰ组 ) ,造模后第 1天 (Ⅱ组 )、第 1周 (Ⅲ组 )、第 2周 (Ⅳ组 )、第 4周 (Ⅴ组 )结肠粘膜NO、NOS的动态变化 ,同时观察其病理改变 ;结果用 x±s表示 ,采用单因素方差分析对数据进行统计学处理 ,以P <0 .0 5作为差异有显著性的检验水准。结果　 1、Ⅱ、Ⅲ、Ⅳ组同Ⅰ、Ⅴ组相比 ,结肠粘膜NOS的活性及NO的水平明显升高 ,经统计学分析差异显著(P <0 .0 1) ,而Ⅰ、Ⅴ组间上述指标差异无显著性 (P >0 .0 5 )。 2、病理学改变 :Ⅰ组未见明显病理学变化 ;Ⅱ、Ⅲ、Ⅳ组粘膜及粘膜下层明显充血、水肿 ,炎性细胞浸润 ,腺体杯状细胞减少 ,有糜烂及溃疡形成 ;Ⅴ组溃疡基本愈合 ,残存溃疡有明显修复性改变 ,如粘膜上皮修复、肉芽组织增生、瘢痕形成等。结论　NOS、NO过量生成和大鼠实验性结肠炎有关。     

Matrix metalloproteinase-9 and vascular endothelial growth factor: a possible link in adult T-cell leukaemia cell invasion

Plasma from a total of 57 patients with adult T-cell leukaemia (ATL) (acute ATL, 39 patients; lymphoma ATL, one patient; chronic ATL, 15 patients; smouldering ATL, two patients) and 20 healthy controls was analysed for the presence of type IV gelatinase activity with clinical features. A significant elevation of plasma matrix metalloproteinase-9 (MMP-9) was observed in some ATL patients, particularly in the patients with malignant cell infiltration. MMP-9 was found to be secreted into the conditioned medium from all ATL cell lines examined. Moreover, the corresponding mRNA was detectable both in all ATL cell lines examined and in the majority of primary acute ATL cells, indicating that ATL cells are capable of synthesizing and secreting MMP-9. We previously demonstrated that a high incidence of ATL cell infiltration was closely related to a high plasma level of vascular endothelial growth factor (VEGF) produced by ATL cells themselves. This present study showed that the presence of increased plasma MMP-9 was closely associated with elevated plasma VEGF in ATL patients. Furthermore, we showed that both increased plasma MMP-9 and VEGF were significantly related to high ATL cell infiltration. All these findings strongly suggest that MMP-9 and VEGF act co-operatively in the process of ATL cell invasion.