Effects of octreotide on jejunal hypersensitivity triggered by Cryptosporidium parvum intestinal infection in an immunocompetent suckling rat model

Background Similar to other bacterial or protozoan infections, human cryptosporidiosis may trigger postinfectious irritable bowel syndrome (IBS)‐like symptoms, a condition in which enhanced visceral perception of pain during intestinal distension plays a pivotal role. In an immunocompetent suckling rat model which mimicks features of postinfectious IBS, Cryptosporidium parvum infection induces long‐lasting jejunal hypersensitivity to distension in association with intestinal activated mast cell accumulation. The aim of the present study was to explore in this model whether octreotide, a somatostatin agonist analog, could prevent the development of jejunal hypersensitivity and intestinal mast cell/nerve fiber accumulation. Methods Five‐day‐old Sprague–Dawley rats were infected with C. parvum and treated 10 days later with octreotide (50 g kg^?1day^?1, i.p.) for 7 days. Key Results Compared with untreated infected rats, octreotide treatment of infected rats resulted in increased weight gain [day 23 postinfection (PI)], decreased food intake (day 16 PI), and a reduction in jejunal villus alterations (day 14 PI), CD3⁺IEL (day 37 PI) and mast cell (days 37 and 50 PI) accumulations, nerve fiber densities (day 50 PI), and hypersensitivity to distension (day 120 PI). In uninfected rats, the effects of octreotide treatment were limited to higher weight gain (days 16 and 23 PI) and decreased food intake (day 23 PI) compared with uninfected‐untreated rats. Conclusions & Inferences Data confirms the relevance of the present rat model to postinfectious IBS studies and prompt further investigation of somatostatin‐dependent regulatory interactions in cryptosporidiosis.     

Cryptosporidium parvum causes gastroenteritis epidemics in the Nablus region of Palestine

A total of 30 faecal samples collected from individuals admitted to a local hospital in Nablus city in Palestine with gastroenteritis symptoms, plus five faecal samples from healthy individuals living in the same area were screened for the presence of Cryptosporidium spp. by microscopic analysis using malachite green negative staining. Molecular techniques were used to confirm the microscopic identification. All 30 samples from individuals with gastroenteritis symptoms were positive by both techniques. No other parasites were found in the faecal material of patients or healthy individuals. To explore the source of the outbreak, water was collected from various reservoirs and springs that supply the city with drinking water. Al‐Qaryoon water spring was found to be contaminated with Cryptosporidium using both microscopic and molecular analysis. No other water resources were found to be contaminated. Genotyping analysis of Cryptosporidium oocysts using PCR‐RFLP technique identified the parasite as C. parvum.     

Lessons from a transplant patient with diarrhea,cryptosporidial infection,and possible mycophenolate mofetil‐associated colitis

P. Frei, A. Weber, A. Geier, J.C. Mertens, S. Kohler, G. Rogler, B. Müllhaupt. Lessons from a transplant patient with diarrhea, cryptosporidial infection, and possible mycophenolate mofetil‐associated colitis.
Transpl Infect Dis 2011: 13: 416–418. All rights reserved Abstract: Diarrhea in a transplant recipient may be caused by infection, metabolic problems, or adverse drug effects. The immunosuppressive drug most frequently associated with diarrhea in transplant recipients is mycophenolate mofetil (MMF). We present the case of a patient with 2 potential explanations for diarrhea lasting several weeks, which occurred years after liver transplantation. Whereas stool samples were positive for cryptosporidia, the histopathological findings were compatible with MMF colitis. However, diarrhea resolved after treatment of cryptosporidial infection, despite continued MMF medication. This case shows that histopathological findings of MMF colitis may be misleading and do not prove that diarrhea is drug induced.     

应用FTA/PCR检测粪便中隐孢子虫的实验研究

目的 建立用FTA/PCR检测粪便中隐孢子虫的技术,并与常用的商业化的粪便DNA抽提试剂盒进行比较.方法 选择经病原学检测已经确诊的隐孢子虫阳性和阴性粪便,分别采用FTA卡和商业化DNA抽提试剂盒抽提粪便样本中DNA,进行巢式PCR扩增,对PCR阳性产物进行测序并利用BLAST在NCBI上与GenBank数据库进行比对,做同源性分析,确定虫种.结果 应用商业化DNA抽提试剂盒抽提DNA,无论是否反复冻融破壁,2个阳性对照样本扩增出目的 片段,另3个阳性样本未扩增出特异性条带.样本纯化后应用FTA卡抽提DNA进行PCR检测,所有阳性粪样均扩增出830 bp左右的目的 片段,通过测序和比对,其中2个为贝氏隐孢子虫,1个为火鸡隐孢子虫.结论 应用FTA进行粪便样本中隐孢子虫DNA的抽提方法具有简单有效、快速灵敏、准确可靠等特点,可以应用于粪便中隐孢子虫的检测.     

安氏隐孢子虫卵囊活力鉴别方法的探讨

目的 鉴别安氏隐孢子虫卵囊的活力.方法 取适量新鲜纯化卵囊,高温灭活.首先用碘化丙啶(propidium iodide,PI)染色法对灭活和未灭活卵囊进行染色,荧光显微镜下观察.同时提取灭活和未灭活两种卵囊的mRNA,反转录作为模板.基于隐孢子虫热激蛋白70(heat shock protein 70,HSP70)基因设计特异引物,用RT-PCR法对卵囊进行鉴别.结果 灭活卵囊经P1染色在荧光显微镜下呈亮红色,而新鲜纯化卵囊无此颜色.新鲜纯化卵囊经RT-PCR法可检测到HSP70的特异条带,而灭活卵囊则无此条带.结论 P1染色法与基于HSP70 mRNA降解的RT-PCR法均可对隐孢子虫卵囊的活力进行鉴别.

Abstract：

Objective To discriminate the viability of oocysts of Cryptosporidium andersoni.Methods Fresh oocysts were purified from cow faeces and then inactivated by high temperature as dead oocysts.To distinguish viable C.andersoni oocysts from dead ones,PI-dye assay Was conducted.At the same time,mRNA was extracted from fresh and inactivated cccysts respectively and RT-PCR was performed to observe the degradation of HSP70 mRNA.Results High temperature treated sample was dyed light-red by PI under fluorescence microscope while fresh oocysts were colorless.Specific band of HSP70 could be detected in fresh oocysts extract while no specific band was observed in inactivated oocysts by RT-PCR.Conclusion PI-dye assay and detection of HSP70 mRNA by RT-PCR Can both be used as method to discriminate the viability of C. andersoni oocysts.     

当归及其多糖对隐孢子虫感染小鼠的免疫调节作用

目的 探讨当归及当归多糖对隐孢子虫感染小鼠的免疫调节作用.方法 连续8 d灌服给小鼠醋酸地赛米松后,于第9 d经口接种1×10^6个隐孢子虫卵囊1次,建立隐孢子虫感染模型,再经当归水煎剂及当归多糖灌胃治疗10 d,计数粪便隐孢子虫卵囊,观察肠组织病理学改变,检测T细胞亚群和血清IL-2、IL-4、IFN-γ水平.并设正常对照、模型对照和西药对照组.结果 与模型组比较,西药组、当归水煎剂组和当归多糖组小鼠卵囊排除数量减少（第4天分别为300个、50个、238个和230个）,肠组织病理学改变较轻,免疫学检测发现CD4^＋T细胞[分别为（38.85±8.16）%、（47.98±11.90）%、（55.85±6.63）%、（51.43±8.42）%]CD4^＋/CD8^＋[分别为1.98±0.47、2.25±0.53、2.51±0.55、2.42±0.23）]及IL-2的水平[分别为（28.75 4±1.93）pg/ml、（69.02±10.47）ps/ml、（42.91±4.48）pg/ml、（40.90±0.79）pg/ml]IL-4的水平[分别为（42.00±6.79）pg/ml、（64.26±6.07）pg/ml、（58.31±9.13）ps/ml、（54.95±8.99）pg/ml]和IFN-γ的水平[分别为（28.73±8.71）ps/ml、（45.40±6.11）pg/ml、（84.40±7.63）pg/ml、（78.40±6.32）pg/ml]明显升高（F值分别为13.58、19.37、24.22、54.36和35.74 P值均小于0.05）.结论 当归水煎剂和当归多糖通过增强机体免疫功能促进隐孢子虫感染的免疫抑制小鼠的恢复.     

HIV/AIDS慢性腹泻患者149例隐孢子虫感染分析

目的分析HIV/AIDS慢性腹泻患者中隐孢子虫感染情况、感染因素及流行特点,为防治隐孢子虫在AIDS患者中的感染提供依据。方法从河南省上蔡县收集AIDS慢性腹泻患者粪便标本149份,采用甲醛-乙酸乙酰沉淀法对患者粪便标本进行集卵,用改良抗酸染色法进行染色检测隐孢子虫卵囊。同时检测患者血液中CD4+T细胞计数。结果 149例HIV/AIDS慢性腹泻患者的粪便标本中24例为隐孢子虫阳性,感染率为16.11%。男性与女性患者及各年龄组感染率比较差异无统计学意义(P均>0.05);HIV/AIDS患者处于HIV无症状期、有症状期和HIV/AIDS期的隐孢子虫感染率分别为0(0/7),25.81%(16/62)和9.88%(8/81),其差异有统计学意义(P<0.05);患者CD4+T细胞水平在<200cells/μL,201～499cells/μL和>500cells/μL的隐孢子虫感染率分别为22.00%(11/50),13.68%(13/95)和0(0/21),差异有统计学意义(P<0.05)。结论 HIV/AIDS慢性腹泻患者中存在着隐孢子虫感染,中晚期患者随着病情的进展,特别是随着CD4+T淋巴细胞水平的降低,感染的危险性明显增高。     

苦参合剂对隐孢子虫感染小鼠空肠黏膜肥大细胞的影响

目的 阐明空肠黏膜肥大细胞激活在隐孢子虫致病机制中的作用, 探讨苦参合剂抗隐孢子虫感染的作用机理。方法 30只雄性BALB/c小鼠随机分为正常对照组、 隐孢子虫感染模型对照组和苦参合剂实验组。建立隐孢子虫肠道感染小鼠模型, 经苦参合剂治疗3周后, 光镜下观察小鼠空肠病理变化; 甲苯胺蓝染色, 计数肥大细胞数量并观察其脱颗粒变化。结果 隐孢子虫感染模型对照组小鼠小肠上皮出现明显炎性病理改变。苦参合剂实验组小鼠治疗3周后小肠上皮较完整, 接近正常。甲苯胺蓝染色显示隐孢子虫感染模型对照组小鼠肥大细胞数量 （12.80±0.84） 较正常对照组 （1.60±0.89）明显增多 （P < 0.01）, 且脱颗粒现象明显; 苦参合剂实验组小鼠肥大细胞数量 （2.00±0.71） 较隐孢子虫感染模型组明显减少（P < 0.01）, 肥大细胞数量和形态接近正常对照组。结论 肥大细胞活化参与了隐孢子虫感染引起的肠黏膜炎症反应。苦参合剂可减少隐孢子虫感染小鼠空肠黏膜肥大细胞数量及抑制肥大细胞活化脱颗粒, 从而减轻炎症、 修复受损肠黏膜, 发挥治疗隐孢子虫病的作用。     

微小隐孢子虫在HCT-8细胞内的培养

目的将人回盲肠癌(HCT-8)细胞作为微小隐孢子虫IId亚型体外感染对象,观察虫体在细胞中的生长发育过程。方法将纯化的隐孢子虫IId亚型感染HCT-8细胞,通过Giemsa染色法观察微小隐孢子虫IId亚型在HCT-8细胞中发育过程,运用PCR方法对不同感染时间点的细胞样品DNA进行检测。结果在感染后72 h内,隐孢子虫出现连续发育阶段,包括脱囊、子孢子、滋养体、裂殖体、配子体、合子和卵囊;PCR的检测结果显示,在感染细胞96 h仍能检测到虫体DNA。结论通过HCT-8细胞,观察到微小隐孢子虫IId亚型的完整的生长发育过程,为抗隐孢子虫药物的筛选提供理论基础,亦可成为微小隐孢子虫IId亚型卵囊体外扩增的方法。