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evidence for a novel entamoeba histolytica lectin activity that recognises carbohydrates present on ovalbumin.entamoeba histolytica, an intestinal amoeba that causes dysentery and liver abscesses, acquires nutrients by engulfing bacteria in the colonic lumen and phagocytoses apoptotic cells during tissue invasion. in preliminary studies to identify ligands that stimulate amoebic phagocytosis, we used ovalbumin immobilized on latex particles as a potential negative control protein. surprisingly, ovalbumin strongly stimulated e. histolytica particle uptake. experiments using highly purified ovalbumin conf ...201120807536
site-specific free energy changes in proteins upon ligand binding by nuclear magnetic resonance: ca2+ -displacement by ln3+ in a ca2+ -binding protein from entamoeba histolytica.the study of protein-ligand interaction has been of a great interest in contemporary structural biology. the understanding of the nature of such interaction and determining the associated binding affinities are of utmost importance. nuclear magnetic resonance has become a powerful tool in deriving information related to such interactions in proteins. nuclear magnetic resonance data provide the site-specific information even in the case of proteins having multiple-binding sites and populations of ...201121235730
amoebic abscess of the spleen and fatal colonic perforation. 201121173680
myeloperoxidase binds to and kills entamoeba histolytica trophozoites.during amebic invasion, neutrophils are a key component in either protecting against invading trophozoites or contributing to tissue damage. upon degranulating or being lysed, neutrophils release toxic substances that can kill amebas as well as damage host tissue. in a previous study we identified a protein from nonspecifically stimulated peritoneal exudates of hamster that has peroxidase and marked amebicidal activity. in the current study we analyzed the in vitro amebicidal effect of purified ...201121204853
amebiasis among persons who sought voluntary counseling and testing for human immunodeficiency virus infection: a case-control study.this case-control study aimed to characterize the factors associated with amebiasis, defined as presence of anti-entamoeba histolytica antibody titers of ≧ 128 by indirect hemagglutination assay, among persons seeking voluntary counseling and testing (vct) for human immunodeficiency virus (hiv) infection. between april 2006 and september 2009, 57 of 4,802 persons (1.2%) seeking vct services were seropositive for e. histolytica infection. compared with 228 seronegative controls, case subjects wer ...201121212204
rna interference in entamoeba histolytica: implications for parasite biology and gene silencing.entamoeba histolytica is a major health threat to people in developing countries, where it causes invasive diarrhea and liver abscesses. the study of this important human pathogen has been hindered by a lack of tools for genetic manipulation. recently, a number of genetic approaches based on variations of the rnai method have been successfully developed and cloning of endogenous small-interfering rnas from e. histolytica revealed an abundant population of small rnas with an unusual 5´-polyphosph ...201121162639
patterns of gastro-intestinal parasites and commensals as an index of population and ecosystem health: the case of sympatric western chimpanzees (pan troglodytes verus) and guinea baboons (papio hamadryas papio) at fongoli, senegal.the exponential decline of great apes over the past 50 years has resulted in an urgent need for data to inform population viability assessment and conservation strategies. health monitoring of remaining ape populations is an important component of this process. in support of this effort, we examined endoparasitic and commensal prevalence and richness as proxies of population health for western chimpanzees (pan troglodytes verus) and sympatric guinea baboons (papio hamadryas papio) at fongoli, se ...201120853397
the epidemiology of soil-transmitted helminth and protozoan infections in south-west cameroon.a cross-sectional study of the prevalence, intensity and effects of soil-transmitted helminth and protozoan infections was undertaken among patients at the buea hospital annex located in buea sub-division of cameroon. stool samples from 356 subjects (174 males and 182 females) were collected and processed using standard concentration methods. our results showed that 31.0% of subjects were infected with intestinal helminths and the prevalence was higher in females (32.4%) than in males (30.5%). a ...201121281528
different structure and mrna expression of entamoeba invadens chitinases in the encystation and excystation.entamoeba histolytica forms chitin-walled cysts during encystation process, where formation of the cyst wall needs not only chitin synthase but also chitinase. during excystation, quadruplet amoebae emerge from the chitin-walled cysts by dissolving the wall, so that chitinase may be necessary for excystation process as well. there is, however, no report on chitinase expression during excystation. in this study, we used entamoeba invadens, a reptilian amoeba, as a model for encystation and excyst ...201121286750
evolutionary genomics of entamoeba.entamoeba histolytica is a human pathogen that causes amoebic dysentery and leads to significant morbidity and mortality worldwide. understanding the genome and evolution of the parasite will help explain how, when and why it causes disease. here we review current knowledge about the evolutionary genomics of entamoeba: how differences between the genomes of different species may help explain different phenotypes, and how variation among e. histolytica parasites reveals patterns of population str ...201121288488
high throughput multiplex pcr and probe-based detection with luminex beads for seven intestinal parasites.polymerase chain reaction (pcr) assays for intestinal parasites are increasingly being used on fecal dna samples for enhanced specificity and sensitivity of detection. comparison of these tests against microscopy and copro-antigen detection has been favorable, and substitution of pcr-based assays for the ova and parasite stool examination is a foreseeable goal for the near future. one challenge is the diverse list of protozoan and helminth parasites. several existing real-time pcr assays for the ...201121292910
structural and biochemical studies of serine acetyltransferase reveal why the parasite entamoeba histolytica cannot form a cysteine synthase complex.cysteine (cys) plays a major role in growth and survival of the human parasite entamoeba histolytica. we report here the crystal structure of serine acetyltransferase (sat) isoform 1, a cysteine biosynthetic pathway enzyme from e. histolytica (ehsat1) at 1.77 å, in complex with its substrate serine (ser) at 1.59 å and inhibitor cys at 1.78 å resolution. ehsat1 exists as a trimer both in solution as well as in crystal structure, unlike hexamers formed by other known sats. the difference in oligom ...201121297164
crystal structures of three protozoan homologs of tryptophanyl-trna synthetase.tryptophanyl-trna synthetase (trprs) is an essential enzyme that is recognizably conserved across all forms of life. it is responsible for activating and attaching tryptophan to a cognate trna(trp) molecule for use in protein synthesis. in some eukaryotes this original core function has been supplemented or modified through the addition of extra domains or the expression of variant trprs isoforms. the three trprs structures from pathogenic protozoa described here represent three illustrations of ...201121255615
entamoeba histolytica: biochemical characterization of a protein disulfide isomerase.protein disulfide isomerase (pdi) enzymes are eukaryotic oxidoreductases that catalyze oxidation, reduction and isomerization of disulfide bonds in polypeptide substrates. here, we report the biochemical characterization of a pdi enzyme from the protozoan parasite entamoeba histolytica (ehpdi). our results show that ehpdi behaves mainly as an oxidase/isomerase and can be inhibited by bacitracin, a known pdi inhibitor; moreover, it exhibits chaperone-like activity. albeit its physiological role i ...201121320491
a sequential model of host cell killing and phagocytosis by entamoeba histolytica.the protozoan parasite entamoeba histolytica is responsible for invasive intestinal and extraintestinal amebiasis. the virulence of entamoeba histolytica is strongly correlated with the parasite's capacity to effectively kill and phagocytose host cells. the process by which host cells are killed and phagocytosed follows a sequential model of adherence, cell killing, initiation of phagocytosis, and engulfment. this paper presents recent advances in the cytolytic and phagocytic processes of entamo ...201121331284
in vivo programmed cell death of entamoeba histolytica trophozoites in a hamster model of amoebic liver abscess.entamoeba histolytica trophozoites can induce host cell apoptosis, which correlates with the virulence of the parasite. this phenomenon has been seen during the resolution of an inflammatory response and the survival of the parasites. other studies have shown that e. histolytica trophozoites undergo programmed cell death (pcd) in vitro, but how this process occurs within the mammalian host cell remains unclear. here, we studied the pcd of e. histolytica trophozoites as part of an in vivo event r ...201121349978
influence of inflammation on parasitism and area of experimental amoebic liver abscess: an immunohistochemical and morphometric study.the influence of inflammation on the number of trophozoites and on the murine amoebic liver abscess area following infection with entamoeba histolytica and e. dispar was evaluated. immunohistochemistry and digital morphometry were used to identify and quantify the trophozoites, neutrophils, macrophages, and lesions. positive correlation was observed between the number of trophozoites and inflammatory cells. a significant decrease in parasitism and inflammation in groups treated with dexamethason ...201121356065
antiprotozoal activity of chloroquinoline based chalcones.a new series of chloroquinoline based chalcones were synthesized and evaluated for in vitro antiamoebic and antimalarial activities. the results showed that out of fifteen compounds, four were found to be more active against the entamoeba histolytica; while one compound was moderatively active compared to the standard drug metronidazole (ic50=1.46 µm). in contrast, in vitro antimalarial activity against the chloroquine-sensitive (3d7) strain of p. falciparum indicated relatively low activity whe ...201121377771
a mutation in the leptin receptor is associated with entamoeba histolytica infection in children.malnutrition substantially increases susceptibility to entamoeba histolytica in children. leptin is a hormone produced by adipocytes that inhibits food intake, influences the immune system, and is suppressed in malnourished children. therefore we hypothesized that diminished leptin function may increase susceptibility to e. histolytica infection. we prospectively observed a cohort of children, beginning at preschool age, for infection by the parasite e. histolytica every other day over 9 years a ...201121393862
synthesis of benzologues of nitazoxanide and tizoxanide: a comparative study of their in vitro broad-spectrum antiprotozoal activity.we have synthesized two new benzologues of nitazoxanide (nit) and tizoxanide (tiz), using a short synthetic route. both compounds were tested in vitro against six protozoa (giardia intestinalis, trichomonas vaginalis, entamoeba histolytica, plasmodium berghei, leishmania mexicana and trypanosoma cruzi). compound 1 (benzologue of nit) showed broad antiprotozoal effect against all parasites tested, showing ic(50)'s<5 ++m. this compound was five-times more active than nit, and 18-times more potent ...201121397502
protective effects of mlif analogs on cerebral ischemia-reperfusion injury in rats.the monocyte locomotion inhibitory factor (mlif) is an anti-inflammatory oligopeptide produced by entamoeba histolytica. among its different effects, it inhibits locomotion of human monocytes, hence its original name. the carboxyl-terminal end group cys-asn-ser is the pharmacophore of anti-inflammatory peptide met-gln-cys-asn-ser. in this study, the n-terminal of cys-asn-ser was modified. with the aim to enhance the antioxidant ability and penetrability of cys-asn-ser, we designed and synthesize ...201121402115
a c2 domain protein kinase initiates phagocytosis in the protozoan parasite entamoeba histolytica.phagocytosis is a process whereby particles are taken in by cells through mechanisms superficially similar to those for endocytosis. it serves a wide range of functions, from providing nutrition in unicellular organisms to initiation of both innate and adaptive immunity in vertebrates. in the protozoan parasite entamoeba histolytica, it has an essential role in survival and pathogenesis. in this study, we show that ehc2pk, a c2-domain-containing protein kinase, and the ca²(+) and actin-binding p ...201121407196
entamoeba histolytica/entamoeba dispar infection in chronic hemodialysis patients.to determine the prevalence of entamoeba histolytica/e. dispar (eh/ed) in chronic hemodialysis (hd) patients, we collected 330 samples of feces from 110 patients, and nine individuals were found to be positive for eh/ed. we compared the infected patients with a group of 14 uninfected hd patients. both groups were analyzed for their signs, symptoms and socio-economic characteristics using questionnaires. blood tests were also performed in both the groups. although both groups did not differ stati ...201121422620
a proteomic and cellular analysis of uropods in the pathogen entamoeba histolytica.exposure of entamoeba histolytica to specific ligands induces cell polarization via the activation of signalling pathways and cytoskeletal elements. the process leads to formation of a protruding pseudopod at the front of the cell and a retracting uropod at the rear. in the present study, we show that the uropod forms during the exposure of trophozoites to serum isolated from humans suffering of amoebiasis. to investigate uropod assembly, we used lc-ms/ms technology to identify protein component ...201121483708
high prevalence of entamoeba infections in captive long-tailed macaques in china.long-tailed macaques (macaca fascicularis) are bred in china for export and for use in experiments. entamoeba infections in captive long-tailed macaques were surveyed in one of the biggest colonies located in guangxi province, china. one stool sample was obtained from each of the 152 different cages representing >3,000 macaques in the colony. the samples were examined by pcr for five entamoeba species. the number of detected entamoeba coli infections comprised 94% of the samples, 93% for entamoe ...201121484347
a novel ex vivo set-up for dynamic long-term characterization of processes on mucosal interfaces by confocal imaging and simultaneous cytokine measurements.we present a novel organ-explant imaging system for easy and cost-effective extended-time observation of host-pathogen interactions at mucosal interfaces. data are complemented by parallel cytokine measurements at high temporal resolution. the set-up is based on a custom-built reusable organ chamber compatible with standard microscopes. luminal and basal side of the explanted mucosa are connected to separate channels for optimized incubation and cytokine measurements, oxygen is provided via memb ...201121496196
melatonin reduces the severity of experimental amoebiasis.abstract:201121501501
validation and utilization of pcr for differential diagnosis and prevalence determination of entamoeba histolytica/entamoeba dispar in salvador city, brazil.amoebiasis is an infection caused by entamoeba histolytica and is a potential health risk in countries in which health barriers are inappropriate. since the discovery of entamoeba dispar, the prevalence of amoebiasis has been modified.201121503397
dna methylation in drosophila--a critical evaluation.drosophila belongs to the so-called "dnmt2 only" organisms, and does not contain any of the canonical dna methyltransferases (dnmt1 and dnmt3). furthermore, no functional homologs of known 5-methylcytosine reader proteins are found. nevertheless, there is strong evidence for dna methylation in this organism. it has been suggested that dna methylation in drosophila is simply a byproduct of dnmt2, which is a dna methyltransferase (dnmt) according to structure and type of catalysis but functions in ...201121507351
involvement of thermoplasmaquinone-7 in transplasma membrane electron transport of entamoeba histolytica trophozoites: a key molecule for future rational chemotherapeutic drug designing.the quinone composition of the transplasma membrane electron transport chain of parasitic protozoa entamoeba histolytica was investigated. purification of quinone from the plasma membrane of e. histolytica and its subsequent structural elucidation revealed the structure of the quinone as a methylmenaquinone-7 (thermoplasmaquinone-7), a napthoquinone. membrane bound thermoplasmaquinone-7 can be destroyed by uv irradiation with a concomitant loss of plasma membrane electron transport activity. the ...201121523408
comparison of the flotac-400 dual technique and the formalin-ether concentration technique for diagnosis of human intestinal protozoon infection.there is a need for accurate diagnosis of intestinal parasite infections in humans, but currently available copromicroscopic techniques have shortcomings, such as low sensitivity. we compared the diagnostic accuracy of a further modified version of the recently developed flotac technique with that of the widely used formalin-ether concentration technique (fect) for the detection of intestinal protozoa in human stool samples. formaldehyde-preserved stool samples from 108 individuals in côte d'ivo ...201121525226
health problems of peacekeepers carrying out mandatory tasks in chad, central africa.background. the article presents the results of the author's own studies concerning the morbidity profile in the group of soldiers serving in the polish military contingent (pmc) deployed to chad in the period may 2008-april 2009 within the framework of a european union operation (eufor) and a united nations peacekeeping mission (minurcat). material and methods. the conducted analysis was based on medical records of soldiers (n = 540) treated at level 1 (fob iriba) and level 2 (hq abeche) medica ...201121534224
the expression of reg 1a and reg 1b is increased during acute amebic colitis.entamoeba histolytica, a protozoan parasite, is an important cause of diarrhea and colitis in the developing world. amebic colitis is characterized by ulceration of the intestinal mucosa. we performed microarray analysis of intestinal biopsies during acute and convalescent amebiasis in order to identify genes potentially involved in tissue injury or repair. colonic biopsy samples were obtained from 8 patients during acute e. histolytica colitis and again 60days after recovery. gene expression in ...201121586335
success of medical therapy in a rare case of cecal ameboma. 201121592907
[perianal cutaneous amebiasis. report of two cases.] 201121592908
genome-wide analysis of mobile genetic element insertion sites.mobile genetic elements (mges) account for a significant fraction of eukaryotic genomes and are implicated in altered gene expression and disease. we present an efficient computational protocol for mge insertion site analysis. elan, the suite of tools described here uses standard techniques to identify different mges and their distribution on the genome. one component, dnascanner analyses known insertion sites of mges for the presence of signals that are based on a combination of local physical ...201121609951
differential distribution of a sine element in the entamoeba histolytica and entamoeba dispar genomes: role of the line-encoded endonuclease.abstract: background: entamoeba histolytica and entamoeba dispar are closely related protistan parasites but while e. histolytica can be invasive, e. dispar is completely non pathogenic. transposable elements constitute a significant portion of the genome in these species; there being three families of lines and sines. these elements can profoundly influence the expression of neighboring genes. thus their genomic location can have important phenotypic consequences. a genome-wide comparison of th ...201121612594
the investigation of entamoeba histolytica prevalence in some villages of sivas by elisa method.objective: humans may be infected with three morphologically identical entamoeba species; pathogenic e. histolytica, commensal e. moshkowskii and e. dispar. the aim of the present study was to determine the true prevalence of the e. histolytica using native lugol, trichrome staining and a monoclonal antigen detection kit (elisa kit e. histolytica-ii; techlab, inc., blacksburg, va) among primary school children living in the rural areas around sivas. methods: a total of 1449 stool samples were ex ...201121618183
[frequency of intestinal parasites among administrators and workers in sanitary and non-sanitary institutions.]objective: transmission of parasites generally occurs through fecal-oral means directly from human to human or through receiving eggs and cysts by means of nourishment. the aim of the study was to investigate the frequency of intestinal parasites among administrators and workers in sanitary and non-sanitary institutions. methods: stool specimens were examined using native-lugol, trichrome and acid-fast stains methods. results: 23.7% of the 2443 fecal specimens were found to be positive. the freq ...201121618189
differentiation of entamoeba histolytica: a possible role for enolase.the study of the encystation process of entamoeba histolytica has been hampered by the lack of experimental means of inducing mature cysts in vitro. previously we have found that cytoplasmic vesicles similar to the encystation vesicles of entamoeba invadens are present in e. histolytica trophozoites only in amebas recovered from experimental amebic liver abscesses. here we report that a monoclonal antibody (b4f2) that recognizes the cyst wall of e. invadens also identifies a 48kda protein in ves ...201121619880
human liver sinusoidal endothelial cells respond to interaction with entamoeba histolytica by changes in morphology, integrin signalling and cell death.invasive infection with entamoeba histolytica causes intestinal and hepatic amoebiasis. in liver, parasites cross the endothelial barrier before abscess formation in the parenchyma. we focussed on amoebae interactions with human hepatic endothelial cells, the latter potentially playing a dual role in the infection process: as a barrier and as modulators of host defence responses. we characterized early responses of a human liver sinusoidal endothelial cell line to virulent and virulence-attenuat ...201121624031
global analysis of gene expression in response to l-cysteine deprivation in the anaerobic protozoan parasite entamoeba histolytica.abstract: background: entamoeba histolytica, an enteric protozoan parasite, causes amebic colitis and extra intestinal abscesses in millions of inhabitants of endemic areas. e. histolytica completely lacks glutathione metabolism but possesses l-cysteine as the principle low molecular weight thiol. l-cysteine is essential for the structure, stability, and various protein functions, including catalysis, electron transfer, redox regulation, nitrogen fixation, and sensing for regulatory processes. r ...201121627801
comparative study between pcr and microscopic examination in diagnosing entamoeba histolytica.differentiation between e. histolytica and non pathogenic species as entamoeba dispar, which are morphologically identical species, is essential for rapid treatment decision, precaution of the invasive disease and public health. this study evaluated the real time pcr for detection of intestinal amoebiasis in comparison with microscopic examination. stool samples were obtained from symptomatic 40 patients from outpatient clinic of benha university hospitals and benha educational hospital. twenty ...201121634245
evaluation of enzyme immunoassay techniques for diagnosis of the most common intestinal protozoa in fecal samples.objective: this study was designed to evaluate the antigen capture enzyme immunoassays (eias) triage parasite panel and techlab entamoeba histolytica ii in detecting giardia intestinalis, cryptosporidium sp, and entamoeba histolytica in fecal samples in comparison to microscopy, and in differentiating entamoeba histolytica from entamoeba dispar. methods: the triage eia was evaluated using 100 stool specimens that were tested by standard ova and parasite examination, including staining with both ...201121636305
structure and biochemical characterization of proliferating cellular nuclear antigen from a parasitic protozoon.proliferating cellular nuclear antigen (pcna) is a toroidal-shaped protein that is involved in cell-cycle control, dna replication and dna repair. parasitic protozoa are early-diverged eukaryotes that are responsible for neglected diseases. in this work, a pcna from a parasitic protozoon was identified, cloned and biochemically characterized and its crystal structure was determined. structural and biochemical studies demonstrate that pcna from entamoeba histolytica assembles as a homotrimer that ...201121636889
evaluation of small-subunit rrna touchdown polymerase chain reaction for direct detection of entamoeba histolytica in human pus samples from patients with amoebic liver abscess.the aim of the present study was to evaluate the use of touchdown polymerase chain reaction (td-pcr) for the detection of entamoeba histolytica in liver pus samples obtained from patients with a clinical diagnosis of amoebic liver abscess (ala) using small-subunit rrna (ssu rrna) as the target gene.201121654108
entamoeba histolytica cathepsin-like enzymes : interactions with the host gut.cysteine proteases of the protozoan parasite entamoeba histolytica are key virulence factors involved in overcoming host defences. these proteases are cathepsin-like enzymes with a cathepsin-l like structure, but cathepsin-b substrate specificity. in the host intestine, amoeba cysteine proteases cleave colonic mucins and degrade secretory immunoglobulin (ig) a and igg rendering them ineffective. they also act on epithelial tight junctions and degrade the extracellular matrix to promote cell deat ...201121660659
risk factors for entamoeba histolytica infection in an agricultural community in hanam province, vietnam.entamoeba histolytica is an important protozoan intestinal infection in resource-poor settings, including vietnam. the study objective was to assess risk factors of e. histolytica infection in a community in vietnam, where wastewater and human excreta are used in agriculture. a case-control study was conducted among residents of hanam province, northern vietnam. cases (n = 46) infected with e. histolytica and non-infected controls (n = 138) were identified in a cross-sectional survey among 794 r ...201121663665
host-parasite interactions in entamoeba histolytica and entamoeba dispar: what have we learned from their genomes?invasive amoebiasis caused by entamoeba histolytica is a major global health problem. virulence is a rare outcome of infection, occurring in fewer than 1 in 10 infections. not all strains of the parasite are equally virulent and understanding the mechanisms and causes of virulence is an important goal of entamoeba research. the sequencing of the genome of e. histolytica and the related avirulent species entamoeba dispar has allowed whole-genome scale analyses of genetic divergence and differenti ...201121810102
intestinal parasitic infections among children in central albania.although intestinal parasitic infections (ipi) among children remain a global issue, the current information on such infections in albanian children is very limited. a cross-sectional study of the ipi in 321 children living in the albanian counties of tirana (152) and elbasan (169) was therefore conducted in 2008, with a pre-tested standard questionnaire employed to gather the relevant personal and clinical data. using formalin-ether concentration and permanent stains, stool samples were examine ...201121801503
factors associated with high prevalence of intestinal protozoan infections among patients in sana'a city, yemen.intestinal protozoan diseases in yemen are a significant health problem with prevalence ranging from 18% to 27%. the present study is a cross-sectional study aimed at determining the factors associated with the high prevalence of intestinal protozoan infections among patients seeking health care in sana'a city, the capital of yemen.201121789210
pathogenic bacteria prime the induction of toll-like receptor signalling in human colonic cells by the gal/galnac lectin carbohydrate recognition domain of entamoebahistolytica.in mixed intestinal infections with entamoeba histolytica trophozoites and enteropathogenic bacteria, which are wide-spread in areas of endemic amebiasis, interaction between the pathogens could be an important factor in the occurrence of invasive disease. it has been reported that exposure of human colonic cells to enteropathogenic bacteria increased trophozoite adherence to the cells and their subsequent damage. we report here that the carbohydrate recognition domain (crd) of the amebic gal/ga ...201121787776
[the epidemiology research of blastocystis hominis in the dokuz eylül university medical faculty hospital between 2005 and 2009].objective: an investigation of blastocystis hominis (b. hominis) prevalance in 17756 patients with gastrointestinal system complaints who presented at the parasitology laboratory of the dokuz eylul university medical faculty hospital between january 2005 and december 2009 was carried out. methods: fecal samples of all patients were examined using the native-lugol and trichrome and kinyoun acid-fast staining method after sedimentation in fecal concentration tubes. results: one or more parasites w ...201121776590
enteric parasites prevalence at saint camille medical centre in ouagadougou, burkina faso.to assess the prevalence of parasitic infections among patients attending saint camille medical centre and to estimate co-parasitic infections rates.201121771685
burden of rotavirus and other enteropathogens among children with diarrhea in burkina faso.objective: there is limited information available regarding the etiology of gastrointestinal infections in burkina faso. the aim of this study was to investigate the prevalence and epidemiology of enteric pathogens causing gastroenteritis in young children, with a focus on rotavirus, and to investigate the levels of malnutrition and other clinical factors in association with the severity of diarrhea. methods: a prospective study was undertaken from may 2009 to march 2010, covering the rainy and ...201121763172
entamoeba histolyticaelectrondense granules secretion in vitro and in vivo: ultrastructural study.electron dense granules (edgs) were identified by transmission electron microscopy in entamoeba histolytica trophozoites recovered from hamster liver lesions. abundant granules were present in trophozoites recovered after 15 min of liver inoculation. variation in the size and morphology of these edgs was also observed. numerous granules were present in the plasma membrane when these parasites were incubated for 5 min with mdck monolayers. release of these edgs was suggested by the presence of gr ...201121761501
evidence of gene conversion in genes encoding the gal/galnac lectin complex of entamoeba.the human gut parasite entamoeba histolytica, uses a lectin complex on its cell surface to bind to mucin and to ligands on the intestinal epithelia. binding to mucin is necessary for colonisation and binding to intestinal epithelia for invasion, therefore blocking this binding may protect against amoebiasis. acquired protective immunity raised against the lectin complex should create a selection pressure to change the amino acid sequence of lectin genes in order to avoid future detection. we pre ...201121738808
intestinal parasites isolated in a large teaching hospital, italy, 1 may 2006 to 31 december 2008.intestinal parasites account for the majority of parasitic diseases, particularly in endemic areas. most are transmitted via contaminated food. because of increased immigration and travel, enteric parasitoses are now distributed worldwide. between may 2006 and december 2008, we examined stool specimens from 5,351 patients (4,695 italians, 656 non-italians) for ova and parasites using microscopy, culture techniques, and molecular methods. stools from 594 patients (11.1%) were contaminated and for ...201121699767
interactions of diarrhea, pneumonia, and malnutrition in childhood: recent evidence from developing countries.this review highlights recent progress toward understanding complex interactions between diarrhea, pneumonia, and undernutrition among children in low-income and middle-income countries.201121734569
detection of zoonotic intestinal parasites in public parks of spain. potential epidemiological role of microsporidia.several studies have demonstrated that the soil of public parks presents an important source of infection which has a significant impact on public health. children are the main group affected by accidentally ingestion of contaminated soil. this study was performed in order to identify the presence of zoonotic parasites in dog and cat faecal and soil samples from public parks of madrid, spain. six hundred twenty-five and seventy-nine soil and faecal samples (presumably from dogs and cats) respect ...201121824364
synthesis, characterization and biological evaluation of novel 2,4,6-trisubstituted bis-pyrimidine derivatives.a new series of 2,4,6-trisubstituted bis-pyrimidines were synthesized and evaluated for in-ávitro antiamoebic activity against hm1:imss strain of entamoeba histolytica. out of 16 compounds 8 compounds have shown ic(50) values in the range of 0.10-1.86-á++m. bis-pyrimidine having methyl-, methoxy-, thiomethyl- and dimehyl-phenyl substituents, exhibited higher antiamoebic activity than the reference drug metronidazole (ic(50)-á=-á1.9-á++m). the toxicological studies of active compounds on pc12-rat ...201121683483
glucose starvation boosts entamoeba histolytica virulence.the unicellular parasite, entamoeba histolytica, is exposed to numerous adverse conditions, such as nutrient deprivation, during its life cycle stages in the human host. in the present study, we examined whether the parasite virulence could be influenced by glucose starvation (gs). the migratory behaviour of the parasite and its capability to kill mammalian cells and to lyse erythrocytes is strongly enhanced following gs. in order to gain insights into the mechanism underlying the gs boosting ef ...201121829737
sulfate activation in mitosomes plays an important role in the proliferation of entamoeba histolytica.mitochondrion-related organelles, mitosomes and hydrogenosomes, are found in a phylogenetically broad range of organisms. their components and functions are highly diverse. we have previously shown that mitosomes of the anaerobic/microaerophilic intestinal protozoan parasite entamoeba histolytica have uniquely evolved and compartmentalized a sulfate activation pathway. although this confined metabolic pathway is the major function in e. histolytica mitosomes, their physiological role remains unk ...201121829746
cryptosporidium and other enteric parasitic infections in hiv-seropositive individuals with and without diarrhoea in osogbo, nigeria.the primary objective of this cross-sectional study is to correlate the presence of cryptosporidium and other gastrointestinal parasites with the presence of diarrhoea in human immunodeficiency virus (hiv)-infected patients. stool samples from 96 hiv-seropositive cases were examined for non-opportunistic parasites using the direct and formol-ether concentration methods, while the modified ziehl-neelsen technique was used to detect cryptosporidium spp. the overall prevalence of cryptosporidium sp ...201121706918
prostaglandin e(2) produced by entamoeba histolytica signals via ep4 receptor and alters claudin-4 to increase ion permeability of tight junctions.entamoeba histolytica is a protozoan parasite that causes amebic dysentery characterized by severe watery diarrhea. unfortunately, the parasitic factors involved in the pathogenesis of diarrhea are poorly defined. prostaglandin e(2) (pge(2)) is a host lipid mediator associated with diarrheal diseases. intriguingly, e. histolytica produces and secretes this inflammatory molecule. we investigated the mechanism whereby ameba-derived pge(2) induces the onset of diarrhea by altering ion permeability ...201121683675
[indications for pcr in travel medicine].the use of pcr-based molecular diagnosis in travel medicine remains limited to specific indications such as clinical suspicion of some of the viral hemorrhagic fevers (e.g. ebola, marburg), differential diagnosis between entamoeba histolytica (pathogen) and e. dispar (non pathogen) in the stools, and parasitological diagnosis of cutaneous leishmaniasis. the scope of indications is likely to expand in the coming years with the development of techniques (e.g. multiplex pcr) able to identify severa ...201121692311
amoebic liver abscess with negative serologic markers for entamoeba histolytica: mind the gap!a 38-year-old male german traveller returning from asia presented with fever, night sweats and abdominal complaints. abdominal ultrasonography revealed several fast-growing abscesses of the liver. three blood cultures as well as serologic investigations for the detection of antibodies to entamoeba histolytica, performed on day 3 and 7 after the onset of clinical symptoms, remained negative. stool microscopy revealed the presence of amoeba cysts compatible with e. histolytica infection. taking bo ...201121735108
epidemiological, clinical, and diagnostic data on intestinal infections with entamoeba histolytica and entamoeba dispar among returning travelers.background: among travelers returning from the tropics, entamoeba spp. are among the most frequently detected intestinal parasites, mainly the presumable apathogenic e. dispar and the pathogenic e. histolytica. methods: among 5,378 travelers seeking diagnosis and treatment for intestinal infections at the travel clinic of the university of munich between 2005 and 2009, 103 laboratory-confirmed amebiasis cases were detected. the study compares the results of various diagnostic tests among these p ...201121717146
mechanism of trifluoromethionine resistance in entamoeba histolytica.objectives to determine the mechanism of trifluoromethionine resistance in entamoeba histolytica and evaluate the impact of acquired drug resistance on virulence. methods trifluoromethionine-resistant amoebae were selected in vitro and examined for cross-resistance to antiamoebic drugs, stability of resistance, methionine +¦-lyase (mgl) activity, cell adhesion and virulence. targeted gene silencing was performed to confirm the role of ehmgl. results trophozoites with a resistance index of 154 we ...201121676903
novel terpene based 1,4,2-dioxazoles: synthesis, characterization, molecular properties and screening against entamoeba histolytica.in present investigation a series of 20 dioxazole analogues (1-20) were synthesized, characterized and subjected to molecular properties prediction, anti-amoebic screening and cytotoxicity evaluation. out of the twenty compounds viz. 3,5-substituted-1,4,2-dioxazoles, six compounds have shown ic(50) values in the range (1.00-1.10-á++m) lower than the standard drug metronidazole (ic(50)-á=-á1.45-á++m). the toxicological studies of the active compounds on h9c2 rat cardiac myoblasts showed that all ...201121715066
a case of amoebic liver abscess complicated by a gastric fistula cured with oral medication only.a 26-year-old man was admitted to our hospital because of a high-grade fever and abdominal pain. a blood test showed marked inflammation. enhanced computed tomography (ct) showed an 8.0+ù6.0cm cystic lesion in the left hepatic lobe. esophagogastroduodenoscopy showed a huge egg-yolk-like mass in the gastric submucosa in the lesser curvature of the gastric body from the gastric angle. there were 3 ulcers on the mass, out of which milky pus flowed. trophozoites of entamoeba histolytica were detecte ...201121817845
nox1 participates in ros-dependent cell death of colon epithelial caco2 cells induced by entamoeba histolytica.entamoeba histolytica, which causes amebic colitis and occasional liver abscesses in humans, can induce host cell death through apoptosis and necrosis. recently, we have demonstrated that e. histolytica can induce cell death in neutrophils via diphenyleneiodonium-sensitive nadph oxidase (nox)-derived reactive oxygen species (ros). although there are enzyme systems similar to the phagocyte nadph oxidase system in many non-phagocytic cell types, the signaling role of nox-derived ros in cell death ...201121723410
invasion mechanisms among emerging food-borne protozoan parasites.food-borne parasitic diseases, many known to be more prevalent in poor countries with deficient sanitary conditions, are becoming common worldwide. among the emerging protozoan parasites, the most prominent is trypanosoma cruzi, rarely reported in the past to be transmitted by the oral route but currently responsible for frequent outbreaks of acute cases of chagas disease contracted orally and characterized by high mortality. several other food-borne protozoans considered emerging include the ap ...201121840261
novelties on amoebiasis: a neglected tropical disease.in accordance with the 1997 documents of the world health organization (who), amoebiasis is defined as the infection by the protozoan parasite entamoeba histolytica with or without clinical manifestations. the only known natural host of e. histolytica is the human with the large intestine as major target organ. this parasite has a very simple life cycle in which the infective form is the cyst, considered a resistant form of parasite: the asymptomatic cyst passers and the intestinal amoebiasis pa ...201121731305
calpains are involved in entamoeba histolytica-induced death of ht-29 colonic epithelial cells.entamoeba histolytica is an enteric tissue-invading protozoan parasite that can cause amebic colitis and liver abscess in humans. e. histolytica has the capability to kill colon epithelial cells in vitro; however, information regarding the role of calpain in colon cell death induced by ameba is limited. in this study, we investigated whether calpains are involved in the e. histolytica-induced cell death of ht-29 colonic epithelial cells. when ht-29 cells were co-incubated with e. histolytica, th ...201121738275
erythema nodosum-like lesions in a renal transplant recipient. 201121690541
structure analysis of entamoeba histolytica enolase.entamoeba histolytica enolase (eheno) reversibly interconverts 2-phosphoglyceric acid (2-pga) and phosphoenolpyruvic acid (pep). the crystal structure of the homodimeric eheno is presented at a resolution of 1.9ôçà+à. in the crystal structure eheno presents as an asymmetric dimer with one active site in the open conformation and the other active site in the closed conformation. interestingly, both active sites contain a copurified 2-pga molecule. while the 2-pga molecule in the closed active sit ...201121697600
Intestinal Parasite Screening in Internationally Adopted Children: Importance of Multiple Stool Specimens.Objective: Our goal was to determine the prevalence of intestinal parasites in internationally adopted children, to examine factors associated with infection, and to determine if evaluating multiple stool specimens increases the yield of parasite identification. Methods: We evaluated internationally adopted children with at least 1 stool specimen submitted for ova and parasite testing within 120 days after arrival to the United States. In children submitting 3 stool specimens, in which at least ...201121824880
benzotriazoles and indazoles are scaffolds with biological activity against entamoeba histolytica.parasitic infections caused by entamoeba histolytica are still major threats against public health, especially in developing countries. although current therapies exist, the problems associated with parasite resistance and negative side effects make it imperative to search for new therapeutic agents. a systematic scaffold analysis reported herein of a public database containing 474 antiamoebic compounds reveals that benzimidazole is the most active scaffold reported thus far. to gain insights in ...201121821786
Rab7 and actin cytoskeleton participate during mobilization of +¦1EHFNR in fibronectin-stimulated Entamoeba histolyticatrophozoites.In vitro interaction of Entamoeba histolytica trophozoites with fibronectin (FN) induces redistribution of the amoebic fibronectin receptor (+¦1EhFNR). Trafficking of beta1 integrins is important for cell adhesion and migration in higher eukaryotes and requires the participation of Rab proteins. In E. histolytica, the machinery involved in integrin trafficking is not completely known. EhRab7 is a 24.5-kDa protein whose alignment with other Rab7 proteins demonstrated that it shared significant ho ...201121823201
study of parasitic infection among children of sukumbasi basti in kathmandu valley.keeping in view of heavy burden of intestinal parasitosis, present study was done to find out the prevalence of intestinal parasitic infection in children (aged <16 years) of sukumbasi (people living without land ownership) basti (community) in kathmandu valley. a total of 279 stool samples collected in clean, dry and screw capped plastic container were firstly examined for the presence of adult worm and/or segments of worms. samples fixed in 10% formal-saline were then examined microscopically ...201121991692
Prevalence and risk factors of helminths and intestinal protozoa infections among children from primary schools in western Tajikistan.Intestinal parasitic infections represent a public health problem in Tajikistan, but epidemiological evidence is scarce. The present study aimed at assessing the extent of helminths and intestinal protozoa infections among children of 10 schools in four districts of Tajikistan, and to make recommendations for control.201121981979
Synchronous tumor with diffuse large B-cell lymphoma and ameboma. 201121947830
calpain mediates degradation of cytoskeletal proteins during jurkat t-cell death induced by entamoeba histolytica.entamoeba histolytica is known to induce host cell death via activation of calpain and caspases. in this study, we investigated the specific proteases involved in the degradation of cytoskeletal proteins during jurkat t-cell death induced by e. histolytica. amoebic trophozoites induced marked degradation of paxillin, cas, vimentin, vinculin and talin, as well as a- or ß-spectrin, in jurkat t cells. the cleavage effects of e. histolytica were strongly retarded by pretreatment with a calpain inhib ...201121426360
evaluation of antidiarrheal and in vitro antiprotozoal activities of extracts of leaves of alocasia indica.alocasia indica schott (araceae) is used in several regions of india, especially in rural communities, by traditional medicine practitioners to treat diarrhea. however, no scientific data are available to justify the traditional potentials of the plant species in gastrointestinal disorders.201121428863
the cysteine protease inhibitors ehicp1 and ehicp2 perform different tasks in the regulation of endogenous protease activity in trophozoites of entamoeba histolytica.trophozoites of e. histolytica are equipped with two chagasin-like cysteine protease inhibitors, ehicp1 and ehicp2, also known as amoebiasin 1 and 2. expression studies using e. invadens as model organism showed that corresponding mrnas were detectable in both life stages of the parasite, cyst and trophozoite state. unlike ehicp1 known to act in the cytosol, ehicp2 co-localized with cysteine protease ehcp-a1 in lysosome-like vesicles, as demonstrated by immunofluorescence microscopy. silencing o ...201121440496
tissue destruction and invasion by entamoeba histolytica.entamoeba histolytica is the causative agent of amebiasis, a disease that is a major source of morbidity and mortality in the developing world. the potent cytotoxic activity of the parasite appears to underlie disease pathogenesis, although the mechanism is unknown. recently, progress has been made in determining that the parasite activates apoptosis in target cells and some putative effectors have been identified. recent studies have also begun to unravel the host genetic determinants that infl ...201121440507
identification of a polypeptide containing tudor and staphyloccocal nuclease-like domains as the sequence-specific binding protein to the upstream regulatory element 1 of entamoeba histolytica.transcription initiation is the most regulated stage for the control of gene expression. this event requires that a complex of proteins called transcription factors bind to dna through cis-regulatory elements located in the gene promoters. however, little is known about transcription regulation in entamoeba histolytica, the protozoan parasite responsible for human amoebiasis. some genes encoding for proteins involved in the parasite pathogenicity contain specific upstream regulatory elements (ur ...201121447339
virulence of entamoeba histolytica: a challenge for human health research. 201121449836
[non-pathogenic intestinal amoebae: a clinical-analytical overview].human beings can be parasitized by various species of intestinal amoebae. entamoeba histolytica is the only intestinal amoeba recognized to be pathogenic, while other amoeba species, e. dispar, e. moshkovskii, e. hartmanni, e. coli, e. polecki, endolimax nana and iodamoeba buetschlii are considered to be non-pathogenic. the aim of this review is to synthesize the main morphological characteristics of the trophozoite and cyst stages of each amoeba as the basis for precise microscopical diagnosis. ...201121458707
[intestinal parasitosis prevalence in outpatients and inpatients of cã granda irccs foundation - ospedale maggiore policlinico of milan: data comparison between 1984-1985 and 2007-2009].this paper evaluates the prevalence of intestinal parasitosis in a specific population over three years (2007-2009). the results were compared with published data collected from the same population in 1984-1985. during a survey from january 1st 2007 to december 31(st) 2009 a total of 2962 inpatients and outpatients were evaluated in our facility (irccs foundation - ospedale maggiore policlinico) for ova and protozoa stool examination (ope) over three specimens collected alternatively for three d ...201121471744
in vitro amoebicidal activity of borage (borago officinalis) extract on entamoeba histolytica.abstract borage (borago officinalis) is a plant with nutritional value that is also used in traditional medicine to treat gastrointestinal disease. this study investigated the amoebicidal activity of a methanol extract of borage. the 50% inhibitory concentration (ic(50)) of the extract for entamoeba histolytica was 33 μg/ml. the 50% lethal dose of the extract for brine shrimp was greater than 1,000 μg/ml. the ic(50) of the extract for vero cells was 203.9 μg/ml. these results support the use of ...201121476887
kinetic characterization and gene expression of adenosine deaminase in intact trophozoites of trichomonas vaginalis.trichomonas vaginalis is a parasite that resides in the human urogenital tract and causes trichomonosis, the most prevalent nonviral sexually transmitted disease. nucleoside triphosphate diphosphohydrolase (ntpdase), which hydrolyzes extracellular di- and triphosphate nucleotides, and ecto-5'-nucleotidase, which hydrolyzes amp, have been characterized in t. vaginalis. the aim of this study was to characterize the adenosine deaminase (ada) activity in intact trophozoites of t. vaginalis. a strong ...201121477257
amoebic dysentery.amoebic dysentery is caused by the protozoan parasite entamoeba histolytica. it is transmitted in areas where poor sanitation allows contamination of drinking water and food with faeces. in these areas, up to 40% of people with diarrhoea may have amoebic dysentery. methods and outcomes: we conducted a systematic review and aimed to answer the following clinical question: what are the effects of drug treatments for amoebic dysentery in endemic areas? we searched: medline, embase, the cochrane lib ...201121477391
molecular differentiation of entamoeba spp. in a rural community of loja province, south ecuador.although previous epidemiological surveys in ecuador indicate the presence of entamoeba histolytica, prevalence data of this parasite remain scarce. most of the studies were based on microscopic examination, which does not allow a morphological differentiation from the non-pathogenic ent. dispar and ent. moshkovskii. in the present study, 674 stool samples from a south ecuadorian rural community were screened for entamoeba spp. subsequently, molecular identification was performed on 101 samples ...201121981992
microbiological spectrum of brain abscess at a tertiary care hospital in south india: 24-year data and review.intracranial abscesses are life-threatening infections that pose a diagnostic challenge not only to the neurosurgeon but also to the microbiologists. detailed studies documenting the spectrum of infecting agents involved in brain abscesses are limited from india. materials and methods. this is a retrospective analysis of 352 samples from 1987 to 2010 analyzed at a tertiary care hospital in south india from 1987 to 2010, to document the changing trends with time. results. the age of the patients ...201122191080
mitosomes in trophozoites and cysts of the reptilian parasite entamoeba invadens.heat shock protein genes led to the discovery of mitosomes in entamoeba histolytica, but mitosomes have not been described for any other entamoeba species, nor have they been identified in the cyst stage. here, we show that the distantly related reptilian pathogen entamoeba invadens contains mitosomes, in both trophozoites and cysts, suggesting all entamoeba species contain these organelles.201121965513
localisation to lipid rafts correlates with increased function of the gal/galnac lectin in the human protozoan parasite, entamoeba histolytica.entamoeba histolytica is the causative agent of dysentery and liver abscess and is prevalent in developing countries. adhesion to the host is critical to infection and is mediated by amoebic surface receptors. one such receptor, the gal/galnac lectin, binds to galactose or n-acetylgalactosamine residues on host components and consists of heavy (hgl), light (lgl) and intermediate (igl) subunits. the mechanism by which the lectin assembles into a functional complex is not known. the parasite also ...201122085647
absence of cd38 delays arrival of neutrophils to the liver and innate immune response development during hepatic amoebiasis by entamoeba histolytica.to define the role of cd38 in the migration of neutrophils to the liver and consequently in the induction of an innate immune response during murine hepatic amoebiasis by entamoeba histolytica, we examined amoebic liver abscess development (ala), presence of amoebae and neutrophils, and expression levels of cytokines and other inflammation mediators mrna, in infected wild-type and cd38 knockout (cd38ko) c57bl/6j mice. results showed that cd38ko mice undergo a delay in ala development in comparis ...201121919917
pcr diagnosis of entamoeba histolytica cysts in stool samples.amebiasis is a protozoan disease caused by entamoeba histolytica and a potential health threat in areas where sanitation and hygiene are inappropriate. highly sensitive pcr methods for detection of e. histolytica in clinical and environmental samples are extremely useful to control amebiasis and to promote public health. the present study compared several primer sets for small subunit (ssu) rdna and histone genes of e. histolytica cysts. a 246 bp of the ssu rdna gene of pure cysts contained in p ...201122072829
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