溶组织内阿米巴5例的粪便鉴定

目的探讨溶组织内阿米巴的粪便鉴定,并就溶组织内阿米巴包囊及滋养体的镜检要点及常见漏检原因进行讨论。方法用显微镜法对5例外院漏诊的肠阿米巴病患者粪便标本进行检验,分别用生理盐水涂片法、碘染色和苏木素染色法,在显微镜下进行观察鉴定。结果溶组织内阿米巴包囊及滋养体在生理盐水涂片、碘染色涂片和苏木素染色涂片中有典型的形态学特点。结论对于可疑肠阿米巴病患者,应多次及时送标本进行检验,采用几种不同方法进行鉴定,并注意将溶组织内阿米巴与吞噬细胞及迪斯帕内阿米巴相鉴别。     

用酶联免疫吸附试验检测粪便中溶组织内阿米巴抗原

肠阿米巴病的确诊,有赖于粪便镜检找到溶组织内阿米巴包囊或滋养体。但此法耗     

双抗体夹心ELISA检测人粪中的溶组织内阿米巴抗原

肠阿米巴病的诊断有赖于粪检发现溶组织内阿米巴滋养体或包囊,但当大量形态上与其相似的非致病性阿米巴类和其它肠原虫存在时,极易误诊。本文报道了用双抗体夹心ELISA检测粪内溶组织内阿米巴滋养体的可溶性抗原,并对其敏感性、特异性及临床应用价值等加以讨论。用培养的溶组织内阿米巴HK 9株制备抗原,并免疫家兔,以饱和硫酸铵分步沉淀得     

实验性大鼠肠阿米巴病的病理学研究——扫描电镜及免疫组织化学观察

用盲肠内接种阿米巴滋养体的方法,复制出大鼠肠阿米巴病动物模型,经组织学及扫描电镜观察发现:感染大鼠的盲肠病变与人类急慢性肠阿米巴病类似,早期为盲肠的弥漫性、非特异性炎症及溃疡形成,晚期为修复愈合与新鲜溃疡同时存在的组织学改变,病变出现高峰在接种后3～7d 间;大鼠感染率为93.6%,盲肠溃疡发生率为43.6%,可作为研究肠阿米巴病的动物模型。应用自行制备的兔抗阿米巴血清对感染的盲肠组织进行免疫组织化学(PAP)染色的结果,证实此法能清楚、准确地显示组织中的阿米巴滋养体,可用于肠阿米巴病的病理诊断及回顾性研究。     

阿米巴胸腔积液的诊断与治疗

阿米巴感染是一种常见病和多发病,全球范围内大约有5000万人感染,每年约10万人死亡。寄生虫病中,阿米巴病是继疟疾和血吸虫后第三位的死亡原因。溶组织内阿米巴(E.histolytica,E.h)是本病的唯一病原体,E.h原虫在人体内以滋养体和包囊体两种形式存在,人感染E.h后既可出现严重的侵袭性阿米巴病症状,也可以处于无症状带虫状     

以实验感染肌肉阿米巴病的仓鼠作为生物学模型

40多年来,动物实验感染溶组织内阿米巴都采用肓肠内或肝内接种的方法。本文作者根据人体阿米巴病的病理学以及溶组织内阿米巴能在人体不同部位生存和发育的事实,用仓鼠进行了肌内感染溶组织内阿米巴的实验研究实验用的溶组织内阿米巴是从急性肠道阿米巴病患者分离出的虫株,已在含有大肠     

阿米巴病的研究现状

1.侵袭性阿米巴病的宿主及寄生虫特异性仅有小部分感染溶组织内阿米巴的个体会发展为有症状的侵袭性阿米巴病。一种假说认为溶组织内阿米巴存在致病株和非致病株。另一种假说则认为所有溶组织内阿米巴均能导致侵袭性阿米巴病,但阿米巴的毒力是不稳定的。无症状的阿米巴肠遭感染和有症状的阿米巴病的临床分离物的同工酶谱是不同的,但不是固定不变的。一个无症状肠道感染者的溶组织内阿米巴分离株克隆,体外与从侵袭性阿米巴结肠炎患者分离的经射线照射的细菌接触,其酶谱从“非致病性”转化为“致病性”,并具备侵袭性阿米巴株的致病特征。     

溃疡性结肠炎合并肠阿米巴病一例

本研究报道1例溃疡性结肠炎合并肠阿米巴病的病例。患者因腹痛伴黏液血便入院诊治,粪便涂片检查发现可疑阿米巴滋养体,血清学和核酸诊断结果提示溶组织内阿米巴感染,结肠镜和病理检查发现患者合并溃疡性结肠炎。经抗阿米巴和抗炎治疗,患者病情好转。本病例提示临床上遇到黏液血便诊断炎症性肠病的患者,如果抗炎辅以常规抗感染治疗效果不佳,...     

云南省罗平县人体溶组织内阿米巴感染情况监测报告

溶组织内阿米巴 (Entamoeba histolytica,Eh)是一种对人类具有严重危害的致病性肠道原虫 ,该虫主要寄生在人体结肠 ,引起阿米巴痢疾 ,在一定条件下 ,可随血液播散引起肠外阿米巴病 ,如阿米巴肝脓肿、脑脓肿、阿米巴心包炎以及皮肤阿米巴病。首次人体寄生虫分布调查结果显示 ,云南省人体溶组织内阿米巴的感染率为 2 .5 4 % [1 ] ,罗平县旧屋基高达 2 0 .5 2 % ,为云南省感染率较高的中签点之一。为掌握其流行特点 ,作者于1999年 7月对该县溶组织内阿米巴的感染情况进行了调查 ,并与历史资料进行了对比分析。1　材料和方法1.1　历史资料的调…     

分离自蛇体的侵入内阿米巴滋养体的培养与应用

将分离自蛇体的侵入内阿米巴(Entamoeba invadens)滋养体接种于营养琼脂血清盐水培养基,22℃恒温培养,每周转种1次。转种后的培养液内含大量滋养体,制成玻片标本,显微镜下观察虫体形态。侵入内阿米巴滋养体的形态变化特点、运动方式、生殖周期和侵袭力等与感染人的溶组织内阿米巴滋养体基本相同。以侵入内阿米巴滋养体代替溶组织内阿米巴滋养体,学生能观察到活体阿米巴滋养体。     

Kupffer cell functions during intestinal amoebiasis in guinea pigs

Kupffer cells play an important role in all alimentary tract infections. Their role in intestinal amoebiasis is not clear. Hence, the present study examined Kupffer cell functions--phagocytic capacity and levels of a key lysosomal enzyme, N-acetyl-beta-glucosaminidase -- in guinea pigs infected with Entamoeba histolytica intracaecally. Animals were sacrificed on days 0, 3, 7, 14 and 21 post-infection. During intestinal amoebiasis the phagocytic capacity in Kupffer cells was depressed, whereas lysosomal enzyme levels were highly elevated. Maximum alteration in Kupffer cell functions was observed on the 14th post-infection day (P less than 0.01). Animals which survived until 21 days post-infection did not show any significant (P greater than 0.05) change in their Kupffer cell functions compared with controls and day zero values. Phagocytic capacity was inversely correlated with severity of caecal lesions. In contrast, enzyme levels were directly correlated with degree of caecal lesions. Similar trends were observed in blood monocytes. The depressed phagocytic capacity of mononuclear phagocytes and the increased enzyme release by these cells accompanying intestinal amoebic infection may contribute to the establishment of the infection and the tissue damage that accompanies it.     

Entamoeba histolytica infection in men who have sex with men

Entamoeba histolytica infection (amoebiasis) is the second leading cause of death from parasitic diseases. Epidemiological studies from developed countries have reported an increasing prevalence of amoebiasis and of invasive infections, such as amoebic colitis, among men who have sex with men (MSM) who engage in oral-anal sex. Although most infections with E histolytica are asymptomatic, clinical manifestations of invasive amoebiasis mainly include amoebic colitis and amoebic liver abscess, which are associated with substantial morbidity and medical cost. Laboratory diagnosis of amoebiasis should be based on detection of E histolytica by use of tests with high sensitivity and specificity, such as specific amoebic-antigen or PCR-based assays. Microscopy used in routine clinical laboratories is not sensitive or specific enough for detection of E histolytica. Metronidazole or tinidazole remains the mainstay of treatment for invasive amoebiasis, followed by treatment with luminal agents to prevent relapse and transmission of E histolytica to sexual partners or close contacts.     

Expression of perforin,granzyme A and Fas ligand mRNA in caecal tissues upon Eimeria tenella infection of naïve and immune chickens

Cytotoxic cells of the immune system may kill infected or transformed host cells via the perforin/granzyme or the Fas ligand (FasL) pathways. The purpose of this study was to determine mRNA expression of perforin, granzyme A and FasL in Eimeria tenella‐infected tissues at primary infection and infection of immune chickens as an indirect measure of cytotoxic cell activity. Chickens were rendered immune by repeated E. tenella infections, which were manifested as an absence of clinical signs or pathological lesions and significantly reduced oocyst production upon challenge infection. During primary E. tenella infection, perforin, granzyme A and FasL mRNA expression in caecal tissue was significantly increased at 10 days after infection, compared to uninfected birds. In contrast, at infection of immune birds, perforin and granzyme A mRNA expression in caecal tissue was significantly increased during the early stages of E. tenella challenge infection, days 1–4, which coincided with a substantial reduction of parasite replication in these birds. These results indicate the activation of cytotoxic pathways in immune birds and support a role for cytotoxic T cells in the protection against Eimeria infections.     

Susceptibility of hamsters to caecal amoebiasis by oral infection

A method is described for successfully establishing caecal amoebiasis in hamsters which were not fed and which were pretreated with 1 ml of magnesium sulphate every 24 hours for three days and then given 12 x 10(5) trophozoites of the HM-1 axenic strain or 18 x 10(5) trophozoites of the HK-9 axenic strain of Entamoeba histolytica by the oral route. All the animals developed diarrhoea within 24 hours of infection. When the animals were killed on the fifth day after infection the caecum was swollen and fused. Large macroscopic ulcers full of pus could be seen in the caecum. None of the control animals showed any of the changes mentioned above.     

中缅边境(西段)阿米巴病危险因素调查

目的了解中缅边境(西段)阿米巴病流行的危险因素。方法 2008年在中缅边境(西段)整群随机抽样中国盈江县那邦镇2个自然村和缅甸拉咱市4个自然村,对调查村内的居民开展流行病学调查及收集粪便标本用ELISA检测溶组织内阿米巴(E.h),用Logistic回归分析可能的影响因素。结果调查中缅居民903人,E.h总感染率为15.2%;其中,中方居民286人,E.h感染率为11.9%;缅方居民617人,E.h感染率为16.7%,中缅居民E.h感染率差异无统计学显著意义(χ2=3.51,P=0.06)。单因素分析表明民族、用手抓饭、喝生水和使用厕所类型为可能的危险因素,多因素分析表明手抓饭和使用厕所类型(公厕)为主要危险因素。结论中缅边境(西段)阿米巴病流行严重,中方居民使用公厕和缅方居民用手抓饭是阿米巴病流行的主要原因。     

Bacterial infections in children with visceral leishmaniasis: observations made in Kerman province, southern Iran, between 1997 and 2007

Cases of human visceral leishmaniasis (VL) are often found to have bacterial infections. Between 1997 and 2007, 60 cases of VL were admitted to the paediatric ward of the Afzalipour Medical Centre, which forms part of the Kerman University of Medical Sciences, in southern Iran. On admission, the 60 cases (39 boys and 21 girls), each of which was confirmed by the demonstration of amastigotes in a bone-marrow aspirate, had a mean (S.D.) age of 48.8 (44.4) months and a mean (S.D.) erythrocyte sedimentation rate of 53.2 (34.2) mm/h. Twenty-five (42%) of the cases (14 boys and 11 girls) were found to have bacterial infections. Urinary infections (seen in 36% of the cases with bacterial infection) were the most common, followed by blood (28%), respiratory (16%), gastro-intestinal (12%) and skin infections (8%). Despite treatment of all the VL cases with meglumine antimoniate, four (7%) died on the paediatric ward, all four having concurrent bacterial infections. The leucopenia and immunosuppression associated with VL probably facilitate the development of fatal bacterial co-infections. The prompt diagnosis and treatment of both the VL and any bacterial co-infections should therefore reduce mortality among VL cases.     

Patterns of adenosine deaminase,ecto-5′-nucleotidase,poly(A)polymerase and surface light chain expression in chronic lymphocytic leukemias

Summary The levels of activity of three enzymes have been measured in the circulating malignant lymphocytes of 47 patients with B chronic lymphocytic leukemia (CLL). These were the purine degrative enzymes, adenosine deaminase (ADA) and ecto-5-nucleotidase (5NT) and the enzyme responsible for the polyadenylation of mRNA, poly(A) polymerase. The patterns of activity of the above enzymes and the expression of surface immunoglobulin light chains were examined. A heterogeneity in the specific activity of the enzymes was observed which could not be attributed to variations of the percentage of B lymphocytes. A positive correlation was found between ADA and poly(A)polymerase activity (r=0.383, p<0.01). Furthermore, the expression of immunoglobulin light chain phenotype was inversely related to 5NT specific activity; CLL cases in which less than 20% of the cells expressed chain phenotype, presented 5NT specific activity of 16.7±3.3 (S.E.) nmol/h/10⁶ cells, whereas in CLL cases with more than 20% of the cells expressing this phenotype the enzyme specific activity was 4.8±1.6 (S.E.) nmol/h/10⁶ cells (p<0.02). These findings suggest that the simultaneous determination of enzymatic activities and immunological markers, might be useful in defining subsets in CLL and the subsequent clinical treatment.     

Determination of antiamoebic IgG, IgM, IgA and IgG subclasses in sera from patients with amoebiasis by enzyme-linked immunosorbent assay

The HK-9 strain of Entamoeba histolytica was cultured axenically. A crude extract of the trophozoites was used as antigen in the enzyme-linked immunosorbent assay (ELISA) for the determination of antiamoebic IgG, IgM, IgA and IgG subclasses in sera of patients with E. histolytica infection. Sera from amoebiasis patients had significantly higher mean ELISA values for all classes and subclasses of immunoglobulins examined compared with healthy controls. The ELISA for IgG, IgM and IgA was positive for 76 (97.4%), 34 (43.6%) and 62 (79.5%) respectively of 78 amoebiasis sera. Analysis of IgG subclasses by ELISA showed that 76.7%, 25%, 33.3% and 66.6% of the patients were positive for antiamoebic IgG1, IgG2, IgG3 and IgG4 respectively. IgG1 and IgG4 were the dominant IgG subclasses involved in amoebiasis. The role of antiamoebic antibodies in amoebiasis is discussed.     

Entamoeba histolytica cysteine proteases cleave the MUC2 mucin in its C-terminal domain and dissolve the protective colonic mucus gel

In order for the protozoan parasite Entamoeba histolytica (E.h.) to cause invasive intestinal and extraintestinal infection, which leads to significant morbidity and mortality, it must disrupt the protective mucus layer by a previously unknown mechanism. We hypothesized that cysteine proteases secreted from the amoeba disrupt the mucin polymeric network, thereby overcoming the protective mucus barrier. The MUC2 mucin is the major structural component of the colonic mucus gel. Heavily O-glycosylated and protease-resistant mucin domains characterize gel-forming mucins. Their N- and C-terminal cysteine-rich domains are involved in mucin polymerization, and these domains are likely to be targeted by proteases because they are less glycosylated, thereby exposing their peptide chains. By treating recombinant cysteine-rich domains of MUC2 with proteases from E.h. trophozoites, we showed that the C-terminal domain was specifically targeted at two sites by cysteine proteases, whereas the N-terminal domain was resistant to proteolysis. The major cleavage site is predicted to depolymerize the MUC2 polymers, thereby disrupting the protective mucus gel. The ability of the cysteine proteases to dissolve mucus gels was confirmed by treating mucins from a MUC2-producing cell line with amoeba proteases. These findings suggest a major role for E.h. cysteine proteases in overcoming the protective mucus barrier in the pathogenesis of invasive amoebiasis. In this report, we identify a specific cleavage mechanism used by an enteric pathogen to disrupt the polymeric nature of the mucin gel.     

Monitoring of local CD8β‐expressing cell populations during Eimeria tenella infection of naïve and immune chickens

The purpose of this study was to monitor abundance and activation of local CD8β‐expressing T‐cell populations during Eimeria tenella infections of naïve chickens and chickens immune by previous infections. Chickens were infected with E. tenella up to three times. Caecal T‐cell receptor (TCR) γ/δ‐CD8β+ cells (cytotoxic T lymphocytes; CTL) and TCRγ/δ+CD8β+ cells were characterized with respect to activation markers (blast transformation, CD25 and cell surface CD107a). Cells were also induced to degranulate in vitro as a measure of activation potential. Major findings included a prominent long‐lasting, up to 6 weeks, increase in the proportion of CTL among caecal CD45+ cells in the later stages after primary E. tenella infection. These CTL also showed clear signs of activation, that is blast transformation and increased in vitro induced degranulation. At second and third E. tenella infection, chickens showed strong protective immunity but discrete signs of cellular activation were observed, for example increased in vitro induced degranulation of CTL. Thus, primary E. tenella infection induced clear recruitment and activation of local CTL. Upon subsequent infections of strongly immune chickens cellular changes were less prominent, possibly due to lower overall numbers of cells being activated because of the severe restriction of parasite replication.