The role of microbiota in hepatic encephalopathy

Hepatic encephalopathy (HE), which consists of minimal (MHE) and overt (OHE) stages, is a model for impaired gut-liver-brain axis in cirrhosis. Microbiota changes in both stages have been associated with impaired cognition, endotoxemia, and inflammation. There is dysbiosis (reduced autochthonous taxa [Lachnospiraceae, Ruminococcaceae, and Clostridiales XIV] and increased Enterobacteriaceae and Streptococcaceae) with disease progression. In MHE, there is an increased abundance of Streptococcus salivarius linked to cognition and ammonia. In OHE, stool Alcaligenaceae and Porphyromonadaceae are associated with poor cognition. Colonic mucosal microbiome in cirrhosis is significantly different compared with stool and independently related to cognition. HE treatment can affect microbial composition and function; cognitive improvement in MHE after rifaximin, a non-absorbable antibiotic, occurred without significant stool microbiota composition change but improved metabolic linkages. Similarly, there are only modest lactulose and rifaximin-associated changes on microbiota composition in OHE. HE represents an important model to study microbiome-brain interactions.     

内毒素诱导的葡萄膜炎大鼠眼内DR5的表达研究

目的 观察内毒素诱导的葡萄膜炎动物模型眼内DR5的表达,研究炎症细胞的凋亡与TRAIL/DR5表达的关系.方法 选取SD大鼠随机分为3组:空白对照组、生理盐水注射组、内毒素注射组.其中内毒素注射组是将内毒素注射到大鼠后足底制成葡萄膜炎动物模型.空白对照组无任何操作,生理盐水注射组以及内毒素注射组又根据注射后不同时间分为6h、12 h、24 h、48 h4个亚组.在注射后不同时间摘除眼球,通过透射电镜观察虹膜毛细血管炎症细胞和内皮细胞的超微结构变化;运用免疫组织化学法检测内毒素诱导后不同时间DR5蛋白在炎症细胞上的表达.结果 透射电镜显示:空白对照组以及生理盐水注射组虹膜组织中毛细血管内皮细胞可见微绒毛、较多的吞饮小泡,未见有明显的结构、形态异常.内毒素注射6h组的毛细血管内皮细胞的吞饮小泡数目开始减少,浸润的中性粒细胞和淋巴细胞出现了染色质边集的表现;24 h组吞饮小泡数目减少明显,大量的中性粒细胞和淋巴细胞出现了染色质浓缩、线粒体空泡样变的凋亡表现.免疫组织化学结果显示:DR5蛋白在空白对照组以及生理盐水注射组大鼠的虹膜色素上皮层呈阴性着色;内毒素注射组中,DR5蛋白在虹膜组织的炎症细胞上呈阳性着色,从6h组炎症细胞就出现,24 h组DR5在炎症细胞中的着色数量及着色强度达到最高,光密度值达到0.085 9±0.019 6,与6h组、12 h组、48 h组比较差异均有统计学意义(均为P＜0.05).结论 TRAIL及其受体DR5可能参与了内毒素诱导的葡萄膜炎中炎症细胞的凋亡.     

碳酸氢钠注射液中微量内毒素的鲎检测法

对浓度大于0.5%的碳酸氢钠溶液以空心纤维型透析器利用双向超滤技术将碳酸氢钠与内毒素分离后,再进行鲎试验,可排除碳酸氢钠对鲎试验凝集反应的抑制作用。方法简便,快速、灵敏度高、回收率好。可作为热原检查的初试方法。     

应用细菌内毒素法检查促肝细胞生长素热原的探讨

参照抑制增强试验,用鲎试剂法检查注射用促肝细胞生长素的细菌内毒素,并与兔法检查热原平行对比,共检查样品256批,两法合格率的符合率为92.2％。     

Changes in the blood endotoxin concentration after digestive surgery

Blood endotoxin concentrations measured in 57 patients with digestive disorders pre- and postoperatively, were found to peak one day after surgery, then gradually return to the preoperative level. The plasma endotoxin concentration was not significantly different in patients with and without liver cirrhosis before surgery, but was significantly higher in the cirrhosis group one day after surgery. The preoperative endotoxin concentration did not correlate with the white blood count (WBC), platelet count, or routine biochemical liver function tests, however, a significant negative correlation was observed between the plasma endotoxin and fibronectin concentrations. The ability of plasma to inactivate endotoxin was quantified by serial measurements of the endotoxin concentration following the addition of a known quantity to each patient's plasma. The plasma from normal subjects quickly inactivated endotoxin, but inactivation was decreased in the plasma from patients with liver failure.     

内毒素休克大鼠模型中一氧化氮稳定代谢物的变化

观察内毒素休克大鼠模型中ＮＯ稳定代谢物的变化及左旋精氨酸、美兰及地塞米松的作用。将５０只大鼠随机分组，测定血、尿ＮＯ－２及ＮＯ－３的变化。结果：ＬＰＳ组血、尿ＮＯ－２及ＮＯ－３比对照组显著增高。美兰组及地塞米松组与ＬＰＳ组比，平均动脉压（ＭＡＰ）下降较少。表明，在内毒素休克微循环障碍中，ＮＯ可能具有重要作用，地塞米松和美兰均可在一定程度上改善其体循环低血压。故ＮＯ抑制剂及ＮＯＳ抑制剂可能对阻抑内毒素休克的恶化具有一定效果。     

家兔烧伤后血浆内毒素和丙二醛水平及早期切痂对其影响

通过复制创面绿脓杆菌感染、背部Ⅱ度30％体表面积烧伤的家兔动物模型，动态检测了烧伤动物血浆内毒素及MDA含量的变化。结果表明：烧伤创面及感染是血中内毒素和氧自由基的重要来源；早期切痂能降低血内毒素和MDA水平。对内毒素影响氧自由基形成及早期切痂影响血中内毒素和MDA水平的机理作了初步探讨。     

Respiratory effects of cotton dust exposure in the cotton garnetting industry

We measured exposures to total dust, vertically elutriated dust, and endotoxin and studied acute pulmonary responses among 128 workers in the cotton garnetting and mattress assembly industries. Previous studies in this segment of industry have not characterized endotoxin exposures or related them to pulmonary responses. The median 8-hour time-weighted average total dust was 0.72 mg/m3, the median vertically elutriated dust was 0.22 mg/m3, and the median endotoxin concentration was 5.2 ng/m3. Ten percent of the subjects reported chest tightness or dyspnea on Mondays. Thirteen percent of the subjects reported symptoms of chronic bronchitis. Although there was no relationship between changes in pulmonary function across the workshift and either total dust, vertically elutriated dust, or endotoxin exposure, 13% of the subjects had greater than 5% decrements in FEV1 over the workshift.     

新喋呤与内毒素对烧伤后多器官功能障碍综合征的诊断价值

目的：探讨循环新喋呤与内毒素对严重烧伤后多器官功能障碍综合征（Ｍｕｌｔｉｐｌｅｏｒｇａｎｄｙｓｆｕｎｃｔｉｏｎｓｙｎｄｒｏｍｅ，ＭＯＤＳ）的诊断价值；方法：对４７例烧伤面积（ＴＢＳＡ）大于３０％（３０％～１００％）患者血清新喋呤、血浆内毒素水平的变化进行动态观察。分别计算新喋呤、内毒素、新喋呤合并内毒素诊断多器官功能障碍综合征（ＭＯＤＳ）的敏感性、特异性及准确性等。结果：根据新喋呤、内毒素对ＭＯＤＳ的预警阈值（３５．０ｎｍｏｌ／Ｌ和５００ＥＵ／Ｌ），新喋呤合并内毒素诊断ＭＯＤＳ的敏感性、特异性及准确性分别为８８．３％、９３．７％、９１．６％，均明显高于单独应用新喋呤或内毒素。结论：动态同步观察循环新喋呤和内毒素水平的变化，对于严重烧伤后ＭＯＤＳ的早期诊断与病程监测具有一定的临床价值。     

血站采血用品细菌内毒素检测的临床意义

目的：通过检测一次性采血器材和注射用液体制剂的细菌内毒素含量，杜绝不合格产品进入血站，为医疗用血机构提供安全、合格的血液制品。方法：对12份检测标本用动态浊度法检测。结果：12份检测标本有2份内毒素含量超标，合格率为83．33％。结论：早期、有效检测一次性采血器材和注射用液体制剂的细菌内毒素是预防内毒素血症发生的重要措施。