肠道贾第虫病42例的临床分析

目的 :观察贾第虫病的临床表现及甲硝唑对贾第虫病的治疗作用。方法 :用甲硝唑治疗 42例贾第虫病患者 ,剂量为 0 .4g,日 3次 ,连服 7～ 10 d为一疗程 ,其中服 1个疗程的有 3 5例 ,服 2个疗程的有 5例 ,服 3个疗程的有 2例。结果 :经治疗后 ,全部患者的症状如腹泻及 (或 )腹痛等胃肠道症状均消失 ,粪检结果恢复正常。患者服药期间的不良反应轻 ,仅有轻微的胃肠道反应 ,如恶心、厌食等。结论 :甲硝唑治疗贾第虫病具有疗效好、耐受性好的优点     

用PCR扩增tim基因检测蓝氏贾第鞭毛虫

采用聚合酶链反应 (PCR)对蓝氏贾第鞭毛虫 (Giardialamblia)的磷酸丙糖异构酶 (triosephosphateisomerase ,缩写为tim)基因进行特异性扩增 ,结果扩增出 1条 6 83bp的DNA片段。此方法的特异性可高达10 0 % ,而其它DNA样本 ,如日本血吸虫 (Schistosomajaponicum)、刚地弓形虫 (Toxoplasmagondii)、微小隐孢子虫 (Cryptosporidiumparvum)、溶组织内阿米巴 (Entamoebahistolytica)、旋毛虫 (Trichinellaspiralis)和阴道毛滴虫 (Trichomonasvaginalis) ,以及人体血细胞等均未出现扩增反应。本法的敏感性也很高 ,可检测到0 4pg贾第虫包囊的DNA。 13株来自不同地理位置和 或宿主的贾第虫DNA样本在PCR中均各产生 1条长为 6 83bp的目的片段。上述结果表明本实验建立的检测贾第虫的PCR方法有效     

蓝氏贾第鞭毛虫承德株分子生物学研究

目的：探讨蓝氏贾第鞭毛虫大、小型包囊存在的原因。方法：用分子生物学技术对３株贾第虫（ＣＨ２、ＣＨ３、ＣＨ４）进行ｔｉｍ基因扩增和序列测定。结果：经与ＧｅｎＢａｎｋ登记虫株比较和用ＤＮＡｓｔａｒ软件处理的结果表明,此３株贾第虫的基因型属２型（ＪＨ型）。结论：大、小型包裹在形态学上经过统计学处理显示有显著差异,但与基因型无关。     

Refractory giardiasis: A molecular appraisal from a tertiary care centre in India

Purpose: The intestinal flagellate Giardia lamblia includes many genetically distinct assemblages, of which assemblage A and B, predominantly infect humans. Nitroimidazoles derivatives (metronidazole and tinidazole) and nitazoxanide are some of the therapeutic agents for treatment of giardiasis. Nevertheless, some individuals with giardiasis are non-responsive to standard therapy. The present study highlights cases of refractory giardiasis and attempts to elucidate if genetic heterogeneity in the parasite is associated with treatment failure. Materials and Methods: Three stool samples were obtained on three consecutive days from 4000 patients with diarrhoea and were microscopically examined for the detection of trophozoites, and/or cysts, using both normal saline and Lugol’s iodine. A hemi-nested polymerase chain reaction (PCR) assay using triose phosphate isomerase (tpi) as the target gene was performed to determine the assemblages. Sequencing of the PCR products of the patients showing failure to treatment of giardiasis was also performed. Results: Two per cent (82/4000) of the total patients were microscopically positive for Giardia lamblia in the stool samples. All these patients were treated with metronidazole/tinidazole as per the standard regimens. However, eight patients showed treatment failure to giardiasis as stool examinations were repeatedly positive even after treatment with multiple courses of anti-giardial therapy. Genetic characterisation of all eight Giardia isolates showed that they belonged to Assemblage B and had homogeneous sequences. These patients were either treated with extended regimens or with combination therapy of anti-giardials. Conclusion: In our experience, combination of two or more drugs for a longer duration is the treatment modality to treat refractory giardiasis.     

单克隆抗体抗贾第虫作用的研究

应用体外纯培养的贾第虫滋养体免疫ＢＡＬＢ／ｃ小鼠和常规杂交瘤细胞技术，制备特异的抗贾第虫单克隆抗体（１Ｅ２，１Ｇ５），以其与贾第虫滋养体相互作用，均发现具有明显的抗贾第虫效果，生长抑制率分别为３５％和６３．４％；将此单抗加入正常培养液中，其含量与抑制率呈现明显的剂量反应关系，相关系数分别为０．９７６４和０．８９８７；单抗经滋养体吸收后，对贾第虫的生长抑制作用消失；经补体灭活前后的豚鼠血清对单抗的抑制作用无影响。     

Antigenic variation in Giardia lamblia: cellular and humoral immune response in a mouse model

Neonatal mice (CR:NIH:S) were infected with a cloned human isolate of Giardia lamblia (GS/M-83-H7) and the surface antigens of the intestinal trophozoites, as well as the cellular and humoral immune responses, were analysed during the course of infection. Infections in mice peaked 2-3 weeks after inoculation and were self-cured by day 42 post-infection (p.i.). The proportion of trophozoites expressing the Mr 72,000 surface antigen of the initial inoculum had decreased by day 12 and approached zero by day 22 p.i., similar to infections in humans. The predominant parasite-specific humoral response was an IgM- and IgG-isotype directed to the original Mr 72,000 surface antigen as well as other antigens. T-lymphocytes (predominantly LY4(CD4)+) isolated from Peyer's patches 12 days p.i. and later showed a significant proliferative response to Giardia lamblia antigens. Spleen and lymph node cells showed no lymphoproliferative response. T-cell blot analysis revealed the presence of dominant T-cell epitopes in the areas of Mr 200,000-75,000 and less than 50,000 polypeptides. No response was demonstrated in the Mr 72,000 region (migration site of the major surface antigen), suggesting T-cell dependent mechanisms are most likely not responsible for the surface antigen switch which occurred during the course of infection. This model infection can be used to study the role of immunological mechanisms in Giardia lamblia variant antigen switching and in the control of infections.     

重组酶介导的蓝氏贾第鞭毛虫特异性等温核酸扩增方法的建立及评价

目的　建立基于重组酶介导的等温扩增技术（RAA）的蓝氏贾第鞭毛虫核酸检测方法,并评价其检测敏感性和特异性。方法　选择蓝氏贾第鞭毛虫β?贾第素（β?giardin）基因作为检测靶基因,设计、合成特异性检测引物及荧光探针,建立荧光RAA检测体系。分别以不同拷贝数的重组质粒（含β?giardin基因靶序列）和不同浓度蓝氏贾第鞭毛虫基因组DNA为模板进行荧光RAA扩增,评价其检测敏感性;分别以蓝氏贾第鞭毛虫、日本血吸虫、华支睾吸虫、微小隐孢子虫、似蚓蛔线虫、沙门氏菌及志贺氏菌基因组DNA为模板进行扩增,评价其检测特异性。结果　成功建立了蓝氏贾第鞭毛虫荧光RAA检测方法,其可在等温（39 ℃）条件下实现对靶基因片段的快速、特异性扩增（20 min内）。分别以重组质粒和蓝氏贾第鞭毛虫基因组DNA为模板,该方法的检测敏感性可达102拷贝/μL和1 pg/μL;以日本血吸虫、华支睾吸虫、微小隐孢子虫、似蚓蛔线虫、沙门氏菌及志贺氏菌基因组DNA为模板的RAA检测结果均为阴性,具备较好特异性。结论　建立了一种操作简便、敏感、特异的可用于蓝氏贾第鞭毛虫核酸检测的荧光RAA方法。     

蓝氏贾第鞭毛虫α-19贾第素的单克隆抗体制备与亚细胞定位研究

目的 制备蓝氏贾第鞭毛虫(Giardia lamblia,简称贾第虫)α-19贾第素的特异性抗体,并通过免疫荧光对该贾第素的亚细胞定位进行鉴定。方法 经PCR获得α-19贾第素编码区片段,双酶切将目的 片段连入原核表达载体pET-28a(+)-α-19,重组载体转化E.coli Rosetta(DE3),IPTG诱导表达,SDS-PAGE及 Western blot验证表达情况;采用设计的合成抗原肽免疫小鼠经细胞融合和筛选制备特异性单克隆抗体,分别用贾第虫滋养体裂解物和α-19贾第素重组蛋白Western blot验证抗体特异性和结合力,选择特异性最好的单克隆抗体通过免疫荧光技术对α-19贾第素的亚细胞定位进行观察。结果 成功构建了原核表达载体pET-28a(+)-α-19,经SDS-PAGE及 Westernblot分析显示重组载体在大肠杆菌中表达出相对分子量约49 kD的重组蛋白,与理论值相符;Western blot显示单克隆杂交瘤细胞株α-19-3-7-3-5分泌的抗体结合力和特异性俱佳,可用于定位研究;免疫荧光定位结果表明α-19贾第素主要位于贾第虫滋养体的腹鞭毛。结论 制备了α-19贾第素的特异性单克隆抗体,免疫荧光显示α-19贾第素定位于贾第虫滋养体的腹鞭毛。     

Establishment of a C57BL/6N mouse model of giardiasis

建立人源蓝氏贾第鞭毛虫C57BL/ 6N小鼠动物感染模型。方法　用分离自河北和江苏两地蓝氏贾第鞭毛虫感染者的包囊 (河北株 ,CD和徐州株 ,XZ)分别感染两组C57BL/6N小鼠 ,收集受染鼠粪便 ,用蔗糖梯度离心法分离纯化包囊 ,计算排囊数量 ,分析排囊规律 ;观察小肠病理组织学改变。结果　C57BL/ 6N小鼠对此 2株蓝氏贾第鞭毛虫具有很高的易感性 ,接受具有活力的 1× 1 0 4 个包囊 /只的 3 6只小鼠 ,均获得感染 ,其中呈间歇性排囊者为 3 2只 ( 88 9% ) ,连续性排囊者 4只 ( 1 1 1 % )。排囊潜伏期为接种后第3d ,高峰期为第 6d。 2小时所排粪便含包囊数最高可达 2 3× 1 0 7个 /g粪。小肠粘膜出现表面分泌物增加 ,间质充血、水肿 ,炎性细胞浸润 ,粘膜坏死脱落等病理变化。结论　C57BL/ 6N小鼠可作为建立蓝氏贾第鞭毛虫感染的良好动物模型     

DNA sequence analysis of the triose phosphate isomerase gene from isolates of Giardia lamblia

目的：为了探讨来源于中国和其它国家不同地理位置贾第虫分离株之间的遗传学关系。方法：从贾第虫滋养体和包囊提取总DNA。对磷酸丙糖异构酶基因进行PCR扩增。PCR产物经限制性内切酶消化、序列测定及分析。对所得DNA序列数据用DNAstar软件处理并与登录基因库虫株的序列比较。结果：在来自我国（C1、C2、CH2、CH3）,柬埔寨（CAM）、澳大利亚（A1、A2）和美国（BP、CDC）的9株蓝氏贾第虫中,A1、A2和CAM属于第1型（WB）;CH2和CH3属于第2型（JH）;C1、C2、BP和CDC属于第3型（GS）。结论：贾第虫分离株基因型的确定可分为本虫分子系统进货和分子流行病学研究提供重要资料。