肠梗阻大鼠小肠黏膜屏障功能变化的实验研究

目的：探讨大鼠肠梗阻时肠黏膜屏障功能的动态变化。方法建立急性完全性小肠梗阻模型,按肠梗阻时间不同进行分组,采血测定血清二胺氧化酶（DAO）的活性和肠型脂肪酸结合蛋白（IFABP）的浓度,取肠系膜淋巴结鉴定细菌移位的发生率并观察小肠组织病理变化。结果肠梗阻12 h后血清IFABP浓度开始升高,随着肠梗阻时间的推移,血清IFABP浓度值逐渐上升,与肠黏膜损伤程度变化趋势一致,两者呈正相关关系（r＝0．841,P＜0．01）。肠梗阻24 h后血清DAO活性升高,至48 h后达峰值,随后下降。大鼠肠梗阻48 h后才开始发生肠系膜淋巴结细菌移位,明显高于假手术组（P＜0．01）。结论肠梗阻早期就发生肠黏膜屏障功能损害,细菌移位滞后于血清生物学指标改变。肠型脂肪酸结合蛋白浓度变化可用来判断肠黏膜损伤程度的生物学指标,为肠梗阻严重并发症的防治和预后评估提供有益的参考和实验依据。     

胡颓子多糖对小肠辐射损伤的保护作用

目的:观察长叶胡颓子多糖对小肠辐射损伤的的保护作用及其机制.方法:昆明小鼠60只随机分为:正常组、辐射组、不同剂量(100,300,500 mg/kg)胡颓子多糖给药组.采用~(60)Coγ射线一次性全身均匀照射建立小肠辐射损伤模型,相应灌胃用药2 wk后,测定小鼠肠段的肠腺存活率百分比和二胺氧化酶(DAO)含量,检测肠黏膜蛋白质和DNA含量(mg/cm),肠组织中SOD活性和MDA含量,血清中TNF、IL-4、IL-6水平.结果:不同剂量长叶胡颓子多糖灌胃均不同程度提高十二指肠、空肠和回肠段肠腺存活率(P<0.05),促进肠黏膜蛋白质、DNA合成(P<0.05或P<0.01),降低血液中TNF水平(6.89±1.33,6.74±1.24,5.87±1.13 vs 8.53±1.08;P<0.05或P<0.01)和MDA含量,提高IL-4(9.79±2.23,10.83±2.34,11.36±2.51 vs 7.40±2.08;P<0.05或P<0.01)、IL-6水平(49.36±9.65,55.26±11.32,59.68±13.65 vs 43.74±12.91;P<0.05或P<0.01)和SOD活性,且与用药剂量呈量效关系.结论:长叶胡颓子多糖通过促进肠黏膜蛋白质和DNA合成、增强抗氧化能力、调节细胞因子异常和损伤修复作用维护肠黏膜的完整性、增强屏障作用,有效减轻小肠辐射损伤.     

肠内营养对克罗恩病血清二胺氧化酶的影响及机制研究

目的:动态观察肠内营养对活动期克罗恩病(CD)病人血清二胺氧化酶(DAO)活性的影响及其机制研究.方法:38例活动期克罗恩病病人,单独给予全肠内营养支持,观察肠内营养使用后第2、4周血清DAO水平的变化,并同步观察血清清蛋白(ALB)、C反应蛋白(CRP)、肿瘤坏死因子-α(TNF-α)、白细胞介素-1β(IL-1β)和IL-6的变化.以53例健康志愿者的血清DAO水平为正常对照.结果:在使用肠内营养前,CD病人血清DAO活性显著低于健康志愿者;使用后第4周,血清DAO水平显著升高,ALB水平呈升高趋势,而CRP、TNF-α、IL-1β、IL-6水平显著下降,并与血清DAO水平的变化呈负相关.结论:肠内营养能够提高CD病人血清DAO活性,并改善病人的营养状况.     

二胺氧化酶在乳腺肿瘤中表达的研究

目的:了解二胺氧化酶(DAO)在乳腺肿瘤中的表达及其对乳腺癌早期诊断的价值.方法:利用自制的小鼠抗人DAO单克隆抗体对60例乳腺肿瘤组织进行免疫组化染色,分析DAO在不同分型乳腺癌中的阳性结果及与临床病理的关系.结果:DAO在乳腺癌组织中有较高的阳性表达率,而在乳腺腺瘤组织表达较低,经统计学处理两者有显著差异(P＜0.01).结论:DAO是乳腺癌早期表达的标志酶,对早期诊断乳腺肿瘤的良恶性程度及预后具有一定的参考价值.     

肝炎肝硬化患者血浆D-乳酸、二胺氧化酶和内毒素的检测及其临床意义

目的　探讨血D 乳酸、二胺氧化酶 (DAO)和内毒素水平在肝炎肝硬化患者中的变化及其临床意义。方法　将 5 0例肝炎肝硬化患者和 3 0例健康体检者分为试验组和对照组 ,采用分光光度法检测外周血中D 乳酸、DAO和内毒素的活性。结果　肝炎肝硬化患者试验组D 乳酸活性明显高于对照组 (P <0 .0 1) ,试验组 3组间比较差异有显著性 (P <0 .0 1) ,治疗后显著低于治疗前 (P <0 .0 1) ;试验组DAO活性明显高于对照组 ,组间比较Child PughC级组活性明显低于Child PughB级组 (P <0 .0 1) ,治疗后A级组及B级组水平显著低于治疗前 (P <0 .0 5 ) ,C级组水平显著高于治疗前 (P <0 .0 5 ) ;Child PughA级组内毒素活性与对照组比较差异显著性 (P >0 .0 5 ) ,Child PughB、C级组明显高于对照组 (P <0 .0 1) ,治疗后A、B级组水平与治疗前比较差异无显著性 (P >0 .0 5 ) ,C级组水平显著降低 (P <0 .0 1)。相关分析显示 3者水平均相关。结论　血浆D 乳酸、DAO水平是肠粘膜损伤早期诊断的敏感指标 ,内毒素血症是肝硬化患者病情加重的重要因素     

Effects of cardiopulmonary bypass on tight junction protein expressions in intestinal mucosa of rats

AIM： To investigate the tight junction protein expressions of intestinal mucosa in an experimental model of cardiopulmonary bypass （CPB） in rats. METHODS： Thirty anesthetized rats were randomly divided into two groups： Group S （n = 10） served as sham operation and group C （n = 20） served as CPB which underwent CPB for 1 h. Expression of occludin and zonula occludens-1 （ZO-1） were determined by Western blotting and immunotochemistry, respectively. Plasma levels of diamine oxidase （DAO） and d-lactate were determined using an enzymatic spectrophotometry. RESULTS： Immunohistochemical localization of occludin and ZO-1 showed disruption of the tight junctions in enterocytes lining villi at the end of CPB and 2 h after CPB. The intensities of the occludin and ZO-i at the end of CPB were lower than those of control group （76.4% ± 22.5% vs 96.5% ± 28.5% and 62.4% ± 10.1% vs 85.5% ±25.6%, P 〈 0.05） and were further lower at 2 h after CPB （50.5% ± 10.5% and 45.3% ± 9.5%, P 〈 0.05）. Plasma d-lactate and DAO levels increased significantly （8.688 ± 0.704 vs 5.745 ± 0.364 and 0.898 ± 0.062 vs 0.562 ± 0.035, P 〈 0.05） at the end of CPB compared with control group and were significantly higher at 2 h after CPB than those at the end of CPB （9.377 ± 0.769 and 1.038 ± 0.252, P 〈 0.05）. There were significant negative correlations between occludin or ZO-1 expression and DAO （r^2 = 0.5629,r^2 = 0.5424, P 〈 0.05） or d-lactate levels （r^2 = 0.6512,r^2 = 0.7073, P 〈 0.05） both at the end of CPB and 2 h after CPB. CONCLUSION： CPB markedly down-regulates the expression of occludin and ZO-1 proteins in intestinal mucosa of rats. The close correlation between expression of tight junctions （TJs） and plasma levels of DAO or d-lactate supports the hypothesis that intestinal permeability increases during and after CPB because of decreases in the expressions of TJs.     

休克后TPN支持导致肠源性感染的实验研究

采用五联悉生大鼠造成创伤后失血性休克和标准全胃肠外营养（ＴＰＮ）支持实验模型，观察休克后不同营养途径对肠屏障功能的影响。结果发现：休克后第８天，与经胃肠道营养（ＴＥＮ）支持组相比，ＴＰＮ支持组各项肠屏障功能指标发生显著变化，表现为肠道菌群紊乱；肠粘膜变薄，微绒毛缩短，粘膜缺损和大量Ｇ－杆菌侵入粘膜和粘膜下层；二胺氧化酶（ＤＡＯ）活性显著下降，肠细胞功能降低。与上述改变相平行，出现肠道细菌易位率增高     

二胺氧化酶在乳腺肿瘤中的表达

二胺氧化酶是一种催化二胺氧化的酶,以前称为组胺酶。本文应用免疫组化LSA'法,对45例乳腺肿瘤进行了DAO检测,并结合其表达情况进行了分析,结果表明,DAO在乳腺癌中多数呈阳性反应,其阳性率为87.5％。癌旁组织和腺瘤组织仅少数表达阳性,阳性率分别为8.6％和10％。DAO在乳腺癌中含量较高,与癌旁组织和腺瘤有非常显著差异(P<0.01)。所以,DAO可以用来做为检测乳腺癌的标志酶。对乳腺癌的早期诊断和治疗可能有一定临床意义。     

Decreased Histamine Catabolism in the Colonic Mucosa of Patients with Colonic Adenoma

Introduction Alterations in mucosal histamine degradation play an important role in various gastrotinestinal diseases including colonic adenoma. In humans, histamine can be catabolized either by oxidative deamination by diamine oxidase (DAO) or by ring methylation by histamine N-methyltransferase (HNMT). The significance of HNMT in this context was investigated for the first time in this project. Methods About 94 colonic biopsies were endoscopically obtained from 23 patients suffering from colonic adenoma and 26 biopsies from six healthy individuals. Each sample was mechanically homogenized, homogenates were cleared by centrifugation and used for determination of protein and histamine concentrations and enzyme activities of DAO and HNMT by radiometric assay. Results In adenoma patients DAO activities were slightly and HNMT activities were significantly decreased in normal mucosa compared to controls. Activities of both enzymes were significantly lower in adenoma tissue than in healthy mucosa in the same patients. A significant correlation was found between HNMT and DAO in all investigated samples. Histamine concentrations were elevated in adenoma patients. Conclusions Histamine catabolism is decreased in the colonic mucosa of patients with colonic adenoma.