Amebic liver abscess rupturing into the lesser omentum space

A case of an amebic abscess localized in the lesser omentum is reported. There was no sign of a liver abscess in the imaging examination or the operative findings. However, it is likely that the amebic infection occurred after a liver abscess ruptured into the abdominal cavity. Early diagnosis and therapy are required when an abscess of unknown origin borders the liver, given the possibility of amebic abscess.     

Additional antiprotozoal constituents from Cuphea pinetorum, a plant used in Mayan traditional medicine to treat diarrhoea

In addition to kaempferol and quercetin already found in the roots from Cuphea pinetorum, bioassay-guided fractionation of the crude extract of the aerial part of this species gave four flavonoid glycosides, quercetin-3-O-alpha-rhamnopyranoside, luteolin-7-O-beta-D-glucopyranoside, apigenin-7-O-alpha-L-rhamnopyranoside and apigenin-7-O-beta-D-glucopyranoside, as well as squalen and beta-sitosterol. In vitro antiamoebic and antigiardial activities of isolated compounds indicated that kaempferol is the principal antiprotozoal agent in C. pinetorum. Based on finding this antiprotozoal inhibitor, flavonoids were studied in order to elucidate structure-activity relationships. These data suggest that kaempferol may play an important role in antidiarrhoeal activity of C. pinetorum.     

Amebiasis in the newborn

Infestation withEntamoeba histolytica is especially common in areas with low socioeconomic status. Extra intestinal invasive involvement is more frequent in young children with significant mortality. This disease is rarely reported in the newborns. This 19-day-old newborn who was infected with orally given surgar solution is presented. He was successfully treated with ornidazole.     

Human amoebic hepatic abscess: in situ interactions between trophozoites, macrophages, neutrophils and T cells

Amoebic liver abscesses (ALA) are the most frequent and severe extraintestinal clinical presentations of amoebiasis. During the early establishment of amoebae in the liver parenchyma, as well as during the extension of the tissue necrosis, parasites interact with the parenchymal liver cells and, as a consequence of these interactions, hepatocytes can be destroyed and host immune cells can become activated. However, little is known about the nature of these interactions in the liver or about the factors involved in the local immune response. In this investigation we studied the localization of Entamoeba histolytica trophozoites, TCD4+, TCD8+ cells, CD68+ macrophages and CD15+ neutrophils in human ALA using immunohistochemical techniques. Trophozoites were found close to undamaged hepatocytes in both lysed and non-lysed areas with either sparse or abundant inflammatory infiltrate. CD8+ cells were more abundant than CD4+ T cells. CD 68+ macrophages and CD15+ neutrophils were also detected, suggesting that neutrophils, macrophages and T cells might be related to the local host immune mechanisms in ALA. We also found that E. histolytica possesses proteins recognized by antibodies raised against inducible nitric oxide synthase.     

A unique Rab GTPase, EhRabA, is involved in motility and polarization of Entamoeba histolytica cells

Entamoeba histolytica, an enteric protozoan parasite, infects 10% of the world's population leading to 50 million cases of invasive amoebiasis annually. Motility, which requires cell polarization, is important to the virulence of this pathogen, as it may result in destruction of host tissues and invasion. To gain insight into these processes in Entamoeba, a unique Rab GTPase, EhRabA, which localizes to the leading edge of cells, was characterized. Cell lines expressing a dominant negative version of EhRabA (EhRabA-DN) were generated. These mutant cells exhibited alterations in cell shape, polarity, and motility, supporting a role for this Rab in the regulation of these processes. Consistent with the notion that a dynamic actin cytoskeleton is crucial to cell polarity and motility, these mutants also exhibited alterations in the actin cytoskeleton. Cells expressing EhRabA-DN also displayed defects in several virulence functions including the ability to adhere to host cells, destroy host cells, and release cysteine proteases. Mislocalization of a prominent adhesion molecule, the galactose/N-acetylgalactosamine (Gal/GalNAc) adherence lectin and reorganization of ordered lipid domains, known as lipid rafts, also accompanied expression of EhRabA-DN. Interestingly, several endocytic processes were unaffected by expression of EhRabA-DN. Together, these data suggest that EhRabA may be involved in the regulation of polarization, motility and actin cytoskeletal dynamics: functions that participate in the pathogenicity of Entamoeba.     

齿龈内阿米巴与牙周炎相关性的研究进展

齿龈内阿米巴(Entamoeba gingivalis,E.gingivalis)主要出现在人口咽部,是最早被报道的人体阿米巴原虫.E.gingivalis通常存在于口腔卫生状况不良及一些口腔疾病患者,特别是牙周炎患者的牙周袋中具有更高的检出率.尽管通常认为E.gingivalis为共生微生物,但随着检测和分析技术的不...     

上海市区不同人群口腔原虫感染的调查

调查上海市区不同人群的口腔原虫的感染情况。从齿垢物取标本作新鲜涂片法检查。在４５０人中齿龈内阿米巴和口腔毛滴虫的感染率分别为２１．７８％和１．１１％。口腔科门诊患者的齿龈内阿米巴的感染率高达２８．３７％，而正常人的感染率仅为１０．７１％，两组差异非常显著。提示这两种原虫的感染与年龄有关，其感染率随年龄的增长有上升趋势，以及两种原虫感染与口腔疾病关系密切。     

Direct amplification of <Emphasis Type="Italic">Entamoeba histolytica</Emphasis> DNA from amoebic liver abscess pus using polymerase chain reaction

An important and serious complication of intestinal infection with Entamoeba histolytica is the involvement of the liver (hepatic amoebiasis). Hepatic amoebiasis is usually diagnosed by the clinical picture (pain in the right upper quadrant and fever), ultrasound examination and positive serology. However, none of these tests are definitive and the picture overlaps with pyogenic liver abscess caused by bacteria. It is for this reason that the feasibility of using polymerase chain reaction (PCR) for the detection of E. histolytica DNA in liver abscess pus was investigated. A comparative study was done to verify the sensitivity of ten pairs of primers specific for detecting E. histolytica in stools. Samples of liver abscess pus from 22 serology-positive patients were collected under ultrasound guidance; and these were used directly in PCR assays without any prior pre-treatment of the samples. Of the ten pairs of previously published primers tested, two pairs of primers (P1 + P2 and P11 + P12) were found to give 100% sensitivity. Based on these results, we recommend that PCR assay can be successfully used to confirm the diagnosis of amoebic liver abscess with the primers identified. Received: 12 March 2000 / Accepted: 18 April 2000     

Risk factors for infection by the Entamoeba histolytica/E. dispar complex: an epidemiological study conducted in outpatient clinics in the city of Manaus, Amazon Region, Brazil

An epidemiological study was conducted on a population attending outpatient clinics in Manaus, Amazon, Brazil to determine the prevalences of infection by the Entamoeba histolytica/E. dispar complex and by E. histolytica alone, as well as to identify the risk factors involved in transmission. The study was conducted in two phases: survey and case-control. Face-to-face interviews were carried out and faecal samples collected from 1578 individuals. Faeces were examined by optical microscopy and tested for the pathogenic E. histolytica specific antigen. Positivity to E. histolytica/E. dispar was 21.5% (340 cases). Cases were compared with 340 control samples, negative for the E. histolytica/E. dispar complex based on examination by optical microscopy. The analysis was conducted by logistic regression. The risk factors identified were: place of residence, age, ingestion of raw vegetables, quality of water consumed, number of rooms and bedrooms per house, and having other protozoan infections. Specific antigen detection tests identified 22 participants infected by E. histolytica (6.8%) among those positive for E. histolytica/E. dispar. There was a higher proportion of males among participants infected by E. histolytica than among those with E. dispar infections. The study population was asymptomatic or presented non-specific symptoms that could be attributed to amoebiasis.     

溶组织内阿米巴半胱氨酸蛋白酶的纯化及其活性的初步研究

目的　探索溶组织内阿米巴通过基底膜进入固有膜的机制 ,了解其半胱氨酸蛋白酶 (cysteine pro-teinase,CP)与胞外基质的相互作用。　方法　阿米巴裂解液通过 laminin- Sepharose亲和层析和分离纯化 ,经分子量测定、测序及抑制剂实验 ,证明为 CP,以凝胶电泳测定其水解活性。　结果　纯化的 CP与 laminin有较强亲和力 ,其分子量为 2 7k Da,被 EC- 6 4所抑制 ,并具水解活性。　结论　溶组织内阿米巴半胱氨酸蛋白酶与胞外基质lam inin特异性结合 ,起水解作用 ,可能是入侵肠粘膜细胞基底膜的关键。