Effect of heat stable and heat labile Escherichia coli enterotoxins, cholera toxin and theophylline on unidirectional sodium and chloride fluxes in the proximal and distal jejunum of weanling swine.

Acute, isolated loops of proximal and distal jejunum of weanling swine were exposed to either heat stable porcine Escherichia coli enterotoxin, heat labile porcine Escherichia coli enterotoxin, cholera toxin or theophylline. Unidirectional sodium fluxes in response to heat stable in the proximal jejunum were dependent on the length of time that the intestinal mucosae was exposed to the enterotoxin. Net water, sodium and chloride and unidirectional sodium and chloride flux measurements in the proximal jejunum in response to each agent uniformly indicated that net secretion of fluid and electrolytes was the result of increased unidirectional sodium secretion or blood-to-lumen flux and decreased unidirectional chloride absorption or lumen-to-blood flux. In addition heat stable cholera toxin and theophylline but not heat labile decreased unidirectional chloride secretion a small but significant amount in the proximal jejunum.Sodium and chloride flux measurements in the distal jejunum demonstrated that all four secretory agents could stimulate net secretion of water, sodium and chloride in that region. The response to these secretory agents as measured by sodium and chloride unidirectional flux rates was not similar to changes observed in the proximal jejunum. In the distal small intestine, whereas heat labile cholera toxin and theophylline induced similar qualitative changes in unidirectional sodium and chloride fluxes, that induced by heat stable differed.     

Effects of intraluminal glucose on intestinal secretion induced by heat stable and heat labile Escherichia coli enterotoxin, cholera toxin and theophylline.

Glucose, l-alanine, l-aspartate, l-methionine and glycine enhanced net fluid and electrolyte absorption in acute isolated loops of the proximal jejunum of weanling swine. The effect of glucose on intestinal secretion induced by heat stable and heat labile Escherichia coli entero-toxin, cholera toxin and theophylline was examined in both the proximal and distal jejunum of weanling swine. In the proximal jejunum glucose enhanced the rate of net fluid and electrolyte absorption. This increase was accompanied by an increase in unidirectional dosium absorption. In loops exposed to either heat stable or heat labile enterotoxins, glucose significantly decreased the rate of net fluid and electrolyte secretion. The magnitude of glucose enhancement in loops exposed to heat stable and heat labile enterotoxins was similar to adjacent control loops. However, glucose enhancement did not occur in loops exposed previously to cholera toxin or concurrently to theophylline. Therefore, cholera toxin and theophylline may inhibit substrate dependent sodium absorption in the proximal jejunum. In the distal jejunum glucose enhancement did occur but the rate of enhancement was less than in the proximal jejunum. In this region glucose enhancement was not evident in loops exposed to either theophylline, heat stable, heat labile or cholera toxin.     

The effect of cholera toxin and heat labile and heat stable Escherichia coli enterotoxin on cyclic AMP concentrations in small intestinal mucosa of pig and rabbit.

The effect of cholera toxin, heat labile and heat stable Escherichia coli enterotoxin on mucosal cyclic AMP concentrations was determined on the proximal jejunum of weanling pigs and young rabbits. Ligated loops were injected with solutions containing no enterotoxin for control and either cholera toxin, heat labile or heat stable E. coli enterotoxin. The loops were drained after either two, four or six hours incubation at which time accumulated fluid was recorded and mucosal samples removed for determination of cyclic AMP concentration. In the rabbit, cholera toxin and heat labile, but not heat stable E. coli enterotoxin stimulated intestinal secretion while in the pig all three enterotoxins induced net fluid accumulation. Cholera toxin and heat labile, but not heat stable E. coli enterotoxin elevated rabbit mucosal cyclic AMP concentrations. In the pig these enterotoxins had no significant effect on mucosal cyclic AMP concentrations. The results are inconsistent with the hypothesis that the adenyl cyclase system is an essential step for enterotoxin induced intestinal secretion. The activation of intestinal adenyl cyclase by bacterial enterotoxins may only be an associated and not a necessary event for the stimulation of intestinal secretion.     

Permeability properties of swine small intestine: effect of a heat stable Escherichia coli enterotoxin.

The permeability of weanling swine small intestine was estimated using measurements of filtration coefficients and equivalent pore size. Hypertonic solutions of mannitol, erythritol and urea were used to calculate reflection coefficients in the duodenum, mid jejunum and distal jejunum. Estimated effective pore radius was 6.4-7.4, 5.6-7.2 and 4.7-4.9A degrees in the three respective regions. Similarly the filtration coefficient induced by hypertonic solutions of mannitol decreased significantly in the distal jejunal segments. The results show an aboral gradient of decreasing permeability along the small intestine of the weanling pig. In situ incubation of loops in the proximal jejunum with a heat stable Escherichia coli enterotoxin for one hour did not significantly change the effective pore size as calculated from reflection coefficients of hypertonic solutions of erythritol and urea. However, the filtration coefficients of loops exposed to the enterotoxin were significantly greater than control loops with hypertonic solutions of erythritol and urea but not mannitol. This suggests the occurrence of a slight reduction in epithelial porosity. The results support the hypothesis that intestinal secretion induced by heat stable E. coli enterotoxin is not the result of an increased mucosal permeability.     

Effect of enteropathogenic Escherichia coli infection on the transmembrane potential of the swine intestine

Transmural potential difference and short-circuit current were measured on membranes of swine small intestine as an index of transport activity for sodium ion. The measurements were made in vitro on membranes prepared from control and E. coli 0138-infected intestinal loops from weanling pigs. Measurements were made on duodenal and upper, middle and lower jejunal segments.No differences were noted in the transmembrane potential difference and the short-circuit current between the control and the experimentally infected loops.     

Chloramphenicol improved expression of recombinant cholera toxin B subunit in Escherichia coli and its adjuvanticity

Background  Cholera toxin B subunit (CTB) was shown to be a potent adjuvant for protein immunogen, especially when inoculated through mucosal route. We aimed to optimize the expression approach for CTB and thereafter to determine the adjuvant effect on DNA vaccine.

Methods  Wild type CTB coding gene was amplified and cloned into prokaryotic expression vector pET-30a, and the recombinant CTB was expressed in the presence of different concentration of chloramphenicol and isopropyl β-D-thiogalactoside. Purified recombinant CTB was mixed with HIV-1 AE2f tat-rev-integrase-vif-nef fusion gene DNA vaccine and female BALB/c mice were vaccinated with a DNA priming-recombinant vaccinia vectored vaccine boosting regimen through intramuscular injection. Interferon γ (IFN-γ) enzyme-linked immunospot (Elispot) assay was used to read out the specific T-cell immunity．

Results  Chloramphenicol was essential for the efficient expression of recombinant CTB (rCTB) in pET-30a/BL21 (DE3) system and could be optimized at the concentration of 0.625 μg/ml in the presence of chloramphenicol. The purified rCTB could bind with GM1 efficiently. INF-γ Elispot data showed the T-cell response induced in CTB adjuvanted group ((734±240) spot forming cells/10⁶ splenocytes) was higher than that induced by non-adjuvanted ((520±150) spot forming cells/10⁶ splenocytes), all responses against different antigens were enhanced in parallel.
Conclusion  CTB could be efficiently expressed in the presence of chloramphenicol and purified CTB is functional and capable of enhancing the specific T cell responses elicited by DNA vaccine, the mechanism needs to be explored in the future.

     

Effect of different treatments on the activity of the heat labile enterotoxin of Escherichia coli F11(P155).

A whole cell lysate preparation of the Escherichia coli strain F11(P155) was treated with the following agents: heat (60 degrees C for 30 minutes), pronase, lipase, amylase, formalin (0.1%), sodium lauryl sulfate (0.05%) and sarkosyl NL30 (0.05%). Except for the amylase treatment, the treated whole cell lysate was inactivated when tested in rabbit gut loops or on Chinese hamster ovary cells. The preparations treated with heat or formalin could be used to produce a neutralizing antiserum or could remove the neutralizing capacity of an anti-F11(P155) serum. Finally, the attempt to demonstrate enterotoxicity with the cytoplasmic membrane of the bacterial cell failed.     

清开灵、双黄连联合头孢哌酮-舒巴坦钠对产ESBLs大肠埃希菌细菌学实验研究

目的 探讨中药消除产ESBLs大肠埃希菌耐药性的作用机理.方法 取来源于临床的ESBLs阳性的大肠埃希菌,建立耐药菌模型.取5 mL无菌试管,共设12个组.取实验菌液,依次加入各组实验试管中,使最终接种量为5×105 CFU/mL.配制清开灵(2倍浓缩液)、双黄连粉针(冻干)、头孢哌酮-舒巴坦钠药液,按照实验分组加入相应药液,并做对倍稀释.中西药联合组分别于0、4、6、8 h后,加入0.5 mL肉汤及头孢哌酮-舒巴坦钠0.5 mL并依次做对倍稀释.35 ℃培养24 h,肉眼观察抑制细菌生长的最低药物浓度即为最低抑菌浓度(MIC).结果 双黄连、清开灵、头孢哌酮-舒巴坦钠对产ESBLs的大肠埃希氏菌的MIC分别为23.04 g/L、62.5 mL/L、39.06 mg/L;双黄连和头孢哌酮-舒巴坦钠联合,最佳效应组合时双黄连MIC降低了98%,头孢哌酮-舒巴坦钠MIC降低了50%;清开灵和头孢哌酮-舒巴坦钠联合,最佳效应组合时清开灵MIC降低了93.75%,头孢哌酮-舒巴坦钠MIC降低了75%.结论 实验证实清开灵注射剂和双黄连粉针对产ESBLs的大肠埃希菌有一定的抑制作用,两药分别与头孢哌酮-舒巴坦钠联合应用有明显的协同作用,可以提高抗生素对耐药菌的敏感性,尤以中药作用4～6 h最佳.     

布地奈德福莫特罗联合小剂量茶碱治疗稳定期重度慢性阻塞性肺疾病疗效观察

目的:研究分析布地奈德福莫特罗联合小剂量茶碱治疗稳定期重度慢性阻塞性肺疾病(COPD)的疗效。方法:选取稳定期重度COPD患者180例,将其动态随机分为两组,研究组和对照组各90例。对照组给予布地奈德福莫特罗进行治疗,研究组在对照组的基础上联合小剂量茶碱进行治疗,对比两组患者的临床疗效与肺功能检测结果。结果:研究组重度COPD患者的临床总有效率为(84.44%),对照组重度COPD患者的临床总有效率为(81.11%),对比两组临床总有效率,差异无统计学意义(P>0.05);分析两组患者肺功能检测结果,研究组患者的肺功能检测结果明显优于对照组,差异有统计学意义(P<0.05)。结论:采用布地奈德福莫特罗联合小剂量茶碱对稳定期重度COPD患者进行治疗,效果显著,能有效改善患者肺功能检测指标,在临床上可以广泛应用。     

The effect of adsorbant and anti-inflammatory drugs on secretion in ligated segments of pig intestine infected with Escherichia coli.

Four adsorbant drug preparations, Kaopectate, colloidal Attapulgite, noncolloidal Attapulgite and Pepto-bismol were investigated for their effects on fluid accumulation in ligated segments of pig intestine inoculated with enteropathogenic Escherichia coli. Two anti-inflammatory drugs. aspirin and methylprednisolone, and two antibiotics, lincomycin and polymyxin B, were also tested. All the drugs except the two anti-inflammatory products were given by injection into the lumen of the intestine. Aspirin was given orally and methylprednisolone was given intramuscularly. The antibiotics were tested at levels at which they had no significant antibacterial effect in in vitro tests. The adsorbant drugs colloidal Attapulgite and Pepto-bismol were shown to be effective in reducing fluid accumulation in ligated segments of pig intestine infected with enteropathogenic E. coli. In the case of Peptobismol this effect was associated with an antibacterial effect as well as an antitoxic effect, probably due to its adsorbant properties. It is possible that an aspirin-like effect in the gut due to the active ingredient bismuth subsalicylate may have contributed to the effectiveness of Pepto-bismol. Colloidal Attapulgite was demonstrated to have an antitoxic effect but did not have an antibacterial effect.In high doses, the anti-inflammatory drugs acetylsalicylic acid and methylprednisolone were marginally effective in reduction of fluid accumulation in the same test system. Lincomycin was shown to reduce intestinal fluid secretion, whereas polymyxin B had no effect.     

Bacterial contamination of the small intestine of infants with enteropathogenic Escherichia coli and other enteric infections: a factor in the aetiology of persistent diarrhoea?

The duodenal microflora was studied during the first week of diarrhoea in 40 infants with acute infectious diarrhoea of different aetiologies and compared with that in a convalescent group and a group in whom diarrhoea of known aetiology had persisted for more than 14 days after an acute onset. In the acute phase 16 of the 40 infants had more than 10(4) colony forming bacteria/ml, predominantly upper respiratory commensals. In over half of the infants infected with enteropathogenic Escherichia coli a faecal type flora was found in the duodenum. This flora included the enteropathogenic E coli serotype isolated from the stool in three quarters of cases. Infants with persisting diarrhoea had significantly more faecal type bacteria in the duodenum than either those with acute diarrhoea or the convalescent group. In addition, there was a significant further increase in Enterobacteriaceae in infants whose persistent diarrhoea occurred after infection with enteropathogenic E coli. Infections with enteropathogenic E coli may have a predilection for disturbing the duodenal microflora, which may contribute to the development of persistent diarrhoea.     

Protective effect and mechanism of sodium tanshinone II A sulfonate on microcirculatory disturbance of small intestine in rats with sepsis

To explore the protective effect of sodium tanshinone ⅡA sulfonate(STS) on microcirculatory disturbance of small intestine in rats with sepsis,and the possible mechanism,a rat model of sepsis was induced by cecal ligation and puncture(CLP).Rats were randomly divided into 3 groups:sham operated group(S),sepsis group(CLP) and STS treatment group(STS).STS(1 mg/kg) was slowly injected through the right external jugular vein after CLP.The histopathologic changes in the intestinal tissue and changes of mesenteric microcirculation were observed.The levels of tumor necrosis factor-α(TNF-α) in the intestinal tissue were determined by using enzyme-linked immunoabsorbent assay(ELISA).The expression of intercellular adhesion molecule-1(ICAM-1) in the intestinal tissue was detected by using immunohistochemisty and Western blot,that of nuclear factor κB(NF-κB) and tissue factor(TF) by using Western blot,and the levels of NF-κB mRNA expression by using RT-PCR respectively.The microcirculatory disturbance of the intestine was aggravated after CLP.The injury of the intestinal tissues was obviously aggravated in CLP group as compared with S group.The expression levels of NF-κB p65,ICAM-1,TF and TNF-α were upregulaed after CLP(P<0.01).STS post-treatment could ameliorate the microcirculatory disturbance,attenuate the injury of the intestinal tissues induced by CLP,and decrease the levels of NF-κB,ICAM-1,TF and TNF-α(P<0.01).It is suggested that STS can ameliorate the microcirculatory disturbance of the small intestine in rats with sepsis,and the mechanism may be associated with the inhibition of inflammatory responses and amelioration of coagulation abnormality.     

运脾汤对胃肠动力障碍大鼠离体小肠运动的影响

目的：观察芳香代表方药一运脾汤对胃肠动力障碍大鼠小肠运动的影响。方法：采用肢体缺血再灌注制备胃肠动力障碍大鼠模型,并应用多导生理记录仪采集各实验组离体小肠机械收缩活动的变化。结果：不同剂量运脾汤对胃肠动力障碍大鼠离体小肠收缩振幅影响不同,低、高剂量组对小肠运动影响无统计学差异（P〉O．05）,中剂量组可明显增加动力障碍大鼠小肠运动振幅,具有统计学差异（P〈O．05）。结论：运脾汤可增加胃肠动力障碍大鼠离体小肠运动振幅,以中剂量组促进作用最为显著。     

Age dependent resistance to transmissible gastroenteritis of swine (TGE). I. Clinical signs and some mucosal dimensions in small intestine

Pigs were exposed to transmissible gastroenteritis (TGE) virus when three days old or when 21 days old. Diarrhea was earliest in onset, most frequent, most profuse and most prolonged in the youngest group. Pigs exposed when three days old also had a higher case fatality rate than those exposed when 21 days old. The histological response of both groups to exposure was atrophy of villi and hyperplasia of crypts in jejunum and ileum. However, from days three to seven post-exposure, when most fatalities occurred in the younger group, atrophy of villi was both more intensive and extensive in the younger group. Hyperplasia of crypts was also greater and more prolonged in the younger group. Regeneration of atrophic villi was more rapid in jejunum than ileum in both groups. Results were interpreted to indicate two populations, with different rates of regeneration, in the 21-day old group. Based on this interpretation, regeneration of villi was more rapid in one population from the 21-day old group than in the three-day old group.The length of villi and depth of crypts in control pigs varied longitudinally (i.e. from site to site) in the intestine, within each age group. Length of villi and depth of crypts in control pigs also varied with age.     

高通量血液透析对尿毒症患者血浆毒素分子含量及机体微炎症状态的影响

目的:观察小剂量碘¹³¹联合甲巯咪唑对甲亢患者甲状腺功能及血清CT、PTH、BGP的影响。方法:将纳入研究的104例甲状腺功能亢进（甲亢）患者随机分为观察组（54例）和对照组（50例）。对照组给予甲巯咪唑治疗,观察组在对照组的基础上给予小剂量碘¹³¹。治疗2个月,观察两组甲状腺功能（TT3、TT4、FT3、FT4、TSH）及骨代谢相关指标（CT、PTH、BGP）的变化。结果:（1）治疗后,两组TT3、TT4、FT3、FT4均较本组治疗前下降（P<0.05）,且观察组降幅更大,两组治疗后同期比较,差异有统计学意义（P<0.05）。两组TSH治疗前后均无明显变化（P>0.05）。（2）治疗后,两组CT、BGP均较本组治疗前下降而PTH上升（P<0.05）,且观察组变化幅度更大,两组治疗后同期比较,差异有统计学意义（P<0.05）。结论:小剂量碘¹³¹联合甲巯咪唑可较快纠正甲亢患者甲状腺功能及骨代谢异常。     

多黏菌素B联合不同抗菌药物抗耐碳青霉烯肺炎克雷伯菌和大肠埃希菌的协同作用

目的:观察多黏菌素B与几种抗菌药物联合抗耐碳青霉烯肺炎克雷伯菌和大肠埃希菌的协同作用.方法:16株碳青霉烯类耐药菌中肺炎克雷伯菌11株,大肠埃希菌5株,观察多黏菌素B与利福平、强力霉素、头孢吡肟、亚胺培南、头孢曲松和庆大霉素对上述菌株的协同作用,通过棋盘微量稀释法确定每种抗菌药物的最小抑菌浓度( MIC)值,根据MIC...     

玻璃酸钠关节腔内注射联合推拿治疗早期原发性膝骨性关节炎

目的:观察推拿联合玻璃酸钠治疗早期膝关节骨性关节炎的疗效.方法:将300例早期膝关节骨性关节炎患者随机分为试验组和对照组.试验组150例,采用推拿联合玻璃酸钠关节腔内注射治疗;对照组150例,采用玻璃酸钠关节腔内注射.观察记录两组患者治疗前、治疗 1 月末、随访 3 月末、5 月末、7 月末疼痛指标(SF-MPQ)和H...     

热应激对小鼠器官指数、小肠损伤及胃HSP70mRNA表达的影响

为了探讨热应激对小鼠器官指数、小肠形态、胃黏膜HSP70 mRNA表达量及糖代谢相关激素的影响。研究采用单因子试验设计, 将年龄和体重相近的18只KM小鼠随机分为对照组和热应激组,分别测定心、肝、脾、肺、肾重量,小鼠胃黏膜HSP70 mRNA表达量、血浆中胰岛素和胰高血糖素浓度以及十二指肠和空肠的绒毛高度、隐窝深度,并对肝脏、十二指肠和空肠进行病理组织学检查。结果表明：热应激对小鼠器官指数无影响,可显著提高小鼠胃黏膜HSP70 mRNA表达量,降低血浆中胰岛素的含量,并造成小鼠肝脏、十二指肠和空肠严重损伤。     

解毒化瘀法对老年稳定性心绞痛患者造影剂肾病的预防作用

[目的] 探讨解毒化瘀法对老年稳定性心绞痛患者造影剂肾病（CIN）的预防作用。[方法] 将184例拟行冠状动脉介入（PCI）治疗的老年稳定性心绞痛患者随机分为对照组（90例）和观察组（94例）,两组在西药常规治疗基础上,观察组在术前3d至术后3d给予解毒化瘀法治疗。所有患者术前及术后3d连续测定血清肌酐（Scr）,术前、术后24h和48h测定尿胱抑素C（Cys-c）、尿白细胞介素-18（IL-18）、肾损伤分子-1（KIM-1）水平,比较两组CIN的发病率。[结果] 观察组术后Scr、尿Cys-c、IL-18、KIM-1水平低于对照组（p<0.01）。两组共发生CIN19例（10.33%）,观察组发生CIN4例（4.26%）,对照组发生15例（16.67%）,两组比较差异有统计学意义（p<0.05）。[结论] 解毒化瘀法可以有效预防老年稳定性心绞痛患者PCI术后造影剂肾病的发生。