Publications

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localization of entamoeba histolytica amebopore in amebic liver abscesses in hamsters.amebopore was purified from axenically grown trophozoites of the entamoeba histolytica strain hm1:imss. the purification procedure involved mono q anion-exchange chromatography and electroelution. sequence analysis of the final product revealed that amebopore a was completely pure. polyclonal antibodies against the purified amebopore were obtained from rabbits, and western blot studies demonstrated their specificity. sections of experimental, acute (1, 2, 3, and 4 days), amebic liver abscesses p ...200819120254
enteric protozoan parasitic infection in hiv seropositive individuals with diarrhoea.a total of 78 hiv seropositive patients were included in the study from january 2004 to march 2006. enteric protozoan parasitic infections were diagnosed by microscopic examination of stool by fresh wet mount, stool smears stained by modified z.n., trichrome and calcofluor white stains. 20 samples (25.6%) revealed presence ofenteric protozoan parasites.200819127672
analysis of autophagy in the enteric protozoan parasite entamoeba.entamoeba histolytica is the enteric protozoan parasite that causes human amoebiasis. we have previously shown that autophagy is involved in proliferation and differentiation in the related species entamoeba invadens, which infects reptiles and develops similar clinical manifestations. because this group of protists possesses only a limited set of genes known to participate in autophagy in other eukaryotes, it potentially represents a useful model for studying the core system of autophagy and pr ...200819185732
a study on the usefulness of techlab entamoeba histolytica ii antigen detection elisa in the diagnosis of amoebic liver abscess (ala) at hospital universiti sains malaysia (husm), kelantan, malaysia.amoebic serodiagnosis at hospital universiti sains malaysia (husm), kelantan employs an indirect haemagglutination assay (iha) which detects anti-entamoeba histolytica antibodies in patients' serum samples. in an amoebiasis endemic area such as kelantan, interpretation of a positive iha result can be problematic due to the high background antibody levels. the techlab e. histolytica ii elisa is a commercial kit for detection of specific gal/galnac lectin antigen in stool samples, and has been rep ...200819287359
intestinal parasitic infections in srimum suburban area of nakhon ratchasima province, thailand.a survey on intestinal parasitic infections and some risk factors of infection (social, economic and behavioral) was conducted in suburban area at simum subdistrict, mueang district, nakhon ratchasima province during the period of april 3rd to april 11th, 2007. a total of 214 stool samples, from 85 males and 129 females were examined using simple direct smear, kato's thick smear and modified harada-mori filter paper strip culture technique. the results showed that the prevalence rate of protozoa ...200819287363
molecular basis of the unusual catalytic preference for gdp/gtp in entamoeba histolytica 3-phosphoglycerate kinase.phosphoglycerate kinase (ec 2.7.2.3) catalyzes reversible phosphoryl transfer from 1,3-bisphosphoglycerate to adp to synthesize 3-phosphoglycerate and atp during glycolysis. phosphoglycerate kinases from several sources can use gdp/gtp as alternative substrates to adp/atp; however, the maximal velocities (v(m)) reached with the guanine nucleotides are approximately 50% of those displayed with the adenine nucleotides. by contrast, entamoeba histolytica phosphoglycerate kinase (ec 2.7.2.10) is the ...200919292872
[epidemiological retrospective survey intestinal parasitism in the provincial hospital center (kenitra, morocco): review of 10 years (1996-2005)].the survey drew up the epidemiological situation of intestinal parasitism in the center of health el idrissi (kenitra, morocco). the number of reviews has decreased between 1996 and 2005. a correlation between the number of examinations and years of the study period was observed (p <0.001). 4285 stool specimens collected in 1996-2005 were tested by parasitologic examination. among the persons examined, 606 of them were parasited by one or several species, say an infestation index of 14.15%. amoe ...200919297294
development of an immunobinding dot-blot assay as an alternative for the serodiagnosis of human cysticercosis.an immunobinding dot-blot assay (dba) was developed on nitrocellulose paper for the serodiagnosis of human cysticercosis, using cysticercus cellulosae as antigen. the dba had an immunological sensitivity of 0.08 mg of antigen protein/ml; however, it showed cross-reactions with antigens of adult taenia solium and echinococcus granulosus, but not with toxoplasma gondii and entamoeba histolytica antigens. an enzyme-linked immunosorbent assay (elisa) was used as the gold standard for obtaining the d ...200919317923
development of loop-mediated isothermal amplification assay for detection of entamoeba histolytica.a novel one-step, closed-tube, loop-mediated isothermal amplification (lamp) assay for detecting entamoeba histolytica, one of the leading causes of morbidity in developing countries, was developed. the sensitivity of the lamp assay is 1 parasite per reaction. a total of 130 clinical samples were analyzed, and the results compared with those of conventional nested pcr to validate the practicability of this assay. no dna was amplified from other diarrheal pathogens, such as other entamoeba specie ...200919321720
prospective case-control study of the association between common enteric protozoal parasites and diarrhea in bangladesh.the parasitic causes of diarrhea have historically been identified by use of microscopy; however, the use of this technique does not allow one to distinguish between subspecies or genotypes of parasites. our objective was to determine, by use of modern diagnostic methods, the proportion of diarrhea cases in bangladesh attributable to cryptosporidium hominis, cryptosporidium parvum, entamoeba histolytica, and giardia lamblia assemblages a and b.200919323634
ameboma of the colon with amebic liver abscess mimicking metastatic colon cancer.amebic colitis is common in developing countries, with its variable and non-specific symptoms. amebomas occur rarely, resulting from the formation of annular granulation tissue, usually in the cecum and in the ascending colon. this report describes the case of a 59-year-old male who presented with abdominal pain. radiological examination depicted concentric thickening of the cecal wall with mass formation and a cystic lesion in the liver. the endoscopy performed showed a growth in the ascending ...200919332922
presence of parasitic protozoa and helminth in sewage and efficiency of sewage treatment in tunisia.helminth eggs and protozoan cysts were enumerated in raw and treated wastewater in tunisia in order to determine their removal by wastewater treatment and to provide quantitative data for developing regulations for wastewater quality that are currently lacking. raw and treated wastewater samples were collected from 17 plants in tunisia during 2006-2007 and analyzed for parasites using the modified bailenger method. two groups of parasites, namely, ascaris sp., entamoeba coli, enterobius vermicul ...200919333622
inter-cellular variation in dna content of entamoeba histolytica originates from temporal and spatial uncoupling of cytokinesis from the nuclear cycle.accumulation of multiple copies of the genome in a single nucleus and several nuclei in a single cell has previously been noted in entamoeba histolytica, contributing to the genetic heterogeneity of this unicellular eukaryote. in this study, we demonstrate that this genetic heterogeneity is an inherent feature of the cell cycle of this organism. chromosome segregation occurs on a variety of novel microtubular assemblies including multi-polar spindles. cytokinesis in e. histolytica is completed b ...200919352422
targeting histone deacetylase inhibitors for anti-malarial therapy.it is now clear that histone acetylation plays key roles in regulating gene transcription in both eukaryotes and prokaryotes, the acetylated form inducing gene expression while deacetylation silences genes. recent studies have identified roles for histone acetyltransferases (hats) and/or histone deacetylases (hdacs) in a number of parasites including entamoeba histolytica, toxoplasma gondii, schistosoma mansoni, cryptosporidium sp., leishmania donovani, neospora caninum, and plasmodium falciparu ...200919355992
oxidative folding and reductive activities of ehpdi, a protein disulfide isomerase from entamoeba histolytica.pdi enzymes are oxidoreductases that catalyze oxidation, reduction and isomerization of disulfide bonds in polypeptide substrates. we have previously identified an e. histolytica pdi enzyme (ehpdi) that exhibits oxidase activity in vivo. however, little is known about the specific role of its redox-related structural features on the enzymatic activity. here, we have studied the in vivo oxidative folding of ehpdi by mutagenic analysis and functional complementation assays as well as the in vitro ...200919361571
proteomic comparison of entamoeba histolytica and entamoeba dispar and the role of e. histolytica alcohol dehydrogenase 3 in virulence.the protozoan intestinal parasite entamoeba histolytica infects millions of people worldwide and is capable of causing amebic dysentery and amebic liver abscess. the closely related species entamoeba dispar colonizes many more individuals, but this organism does not induce disease. to identify molecular differences between these two organisms that may account for their differential ability to cause disease in humans, we used two-dimensional gel-based (dige) proteomic analysis to compare whole ce ...200919365541
[detection of entamoeba histolytica in stool specimens with the elisa method].in this study, carried out between november 2006 and september 2007, amebic cysts were observed in 44 (0.37%) out of a total of 1720 stool specimens which were examined by direct microscopy. entamoeba histolytica specific antigen was investigated with elisa in the specimens in which cysts were observed. specific antigen was detected in 26 (59.1%) of these specimens. the diagnosis of amoebiasis for the patients whose elisa tests were positive was confirmed and the appropriate therapy was immediat ...200919367537
[the determination of intestinal parasites, physical growth and hygiene behaviors of children in the mersin city social service child care centre].intestinal parasites are still a major health problem in our country. the aim of this study was the determination of intestinal parasites, physical growth and hygiene behavior of a total of 106 children living in the mersin city social service child care centre and who could participate in this research. a questionnaire form was used to determine the socio-demographic features and hygienic behavior of the children, and their weight and height were measured in order to determine their physical gr ...200919367550
thymidine kinase and uridine-cytidine kinase from entamoeba histolytica: cloning, characterization, and search for specific inhibitors.entamoeba histolytica is an intestinal parasite and the causative agent of amoebiasis, which is a significant source of morbidity and mortality in developing countries. although anti-amoebic drugs such as metronidazole, emetine, chloroquine and nitazoxanide are generally effective, there is always potential for development of drug resistance. in order to find novel targets to control e. histolytica proliferation we cloned, expressed and purified thymidine kinase (eh-tk) and uridine-cytidine kina ...200919368743
antiamoebic drugs for treating amoebic colitis.entamoeba histolytica infection is common in developing countries, and up to 100,000 individuals with severe disease die every year. adequate therapy for amoebic colitis is necessary to reduce the severity of illness, prevent development of complicated disease and extraintestinal spread, and decrease transmission.200919370624
computational study of the electronic structure characterization of a novel anti-inflammatory tripeptide derived from monocyte locomotion inhibitory factor (mlif)-pentapeptide.the structure and properties of molecules are determined by their charge-density distribution. several works have shown that electron delocalization along the peptide backbone and side-chain modulates the physical and chemical features of peptides and protein properties. research on entamoeba histolytica-soluble factors led to the identification of the pentapeptide met-gln-cys-asn-ser, with anti-inflammatory in vivo and in vitro effects. a synthetic pentapeptide, met-pro-cys-asn-ser, maintained ...200919371982
molecular nature of virulence in entamoeba histolytica.for many years virulence of pathogenic entamoeba histolytica has been attributed to the capacity of the parasite to destroy tissues through the expression and/or secretion of various molecules. such view is supported mainly by in vitro experimentation, whereas data obtained by using animal models of the disease have clearly demonstrated that the host's inflammatory response is primarily responsible for tissue damage. this review analyzes the content and/or activity of some of the presumed toxic ...200919376272
overexpression of a mutant form of ehraba, a unique rab gtpase of entamoeba histolytica, alters endoplasmic reticulum morphology and localization of the gal/galnac adherence lectin.entamoeba histolytica is a protozoan parasite that causes amoebic dysentery and liver abscess. vesicle trafficking events, such as phagocytosis and delivery of plasma membrane proteins, have been implicated in pathogenicity. rab gtpases are proteins whose primary function is to regulate vesicle trafficking; therefore, understanding the function of rabs in this organism may provide insight into virulence. e. histolytica possesses a number of unique rabs that exhibit limited homology to host rabs. ...200919377040
synthesis of novel hybrid molecules from precursors with known antiparasitic activity.three novel new compounds derived from antiparasitic precursors have been synthesized and tested for their antiamoebic and antigiardial activities. the condensation of 2-(2-methyl-5-1h-nitroimidazolyl)ethylamine (6) with 5-nitro-2-furylacrylic acid (7) gave 3-(5-nitrofuran-2-yl)-n-[2-(5-nitroimidazol-1-yl)ethyl]acrylamide (8). condensation of 7 with 7-chloro-4-(piperazin-1-yl)quinoline (9) afforded 1-[4-(7-chloroquinolin-4-yl)piperazin-1-yl)-3-(5-nitrofuran-2-yl)propenone as a mixture of two iso ...200919384280
n- and c-terminal domains of the calcium binding protein ehcabp1 of the parasite entamoeba histolytica display distinct functions.entamoeba histolytica, a protozoan parasite, is the causative agent of amoebiasis, and calcium signaling is thought to be involved in amoebic pathogenesis. ehcabp1, a ca(2+) binding protein of e. histolytica, is essential for parasite growth. high resolution crystal structure of ehcabp1 suggested an unusual arrangement of the ef-hand domains in the n-terminal part of the structure, while c-terminal part of the protein was not traced. the structure revealed a trimer with amino terminal domains of ...200919384409
entamoeba histolytica: cysteine proteinase activity and virulence. focus on cysteine proteinase 5 expression levels.cysteine proteinase (cp) activity and cp5 mrna levels were analyzed in eleven samples of entamoeba histolytica isolated from patients presenting different clinical profiles. the virulence degree of the isolates, determined in hamster liver, correlated well with the clinical form of the patient and culture conditions. cp5 mrna levels were also determined in sample freshly picked up directly from liver amoebic abscess. differences were not observed in the levels of cp5 mrna and cp specific activit ...200919389401
pleural empyema secondary to amebic liver abscess. 200919389640
frequency of human toxocariasis in a rural population from cajamarca, peru determined by dot-elisa test.the aim of this study was to estimate the frequency of human toxocariasis in cauday district, cajamarca, peru, using a dot-elisa test. from june to october 2005, a total of 256 adult subjects were studied. blood samples were collected for serology by a dot-elisa test and for hematological examination. parasitological examination was also carried out in stool samples to check cross-reactions in the dot-elisa. the frequency observed was 44.92%, with a significant higher proportion of positivity in ...200919390733
coinfections with schistosoma haematobium, necator americanus, and entamoeba histolytica/entamoeba dispar in children: chemokine and cytokine responses and changes after antiparasite treatment.the effect of polyparasite infections on cytokine and chemokine responses as well as the effect of antiparasite treatment was studied in children without parasite infection (the g0 group), in children singly infected with schistosoma haematobium (the g1 group), and in children multiply infected with s. haematobium/schistosoma mansoni, entamoeba histolytica/entamoeba dispar, and necator americanus (the g3+ group). linear regression analysis disclosed a significant risk for coinfection with hookwo ...200919392635
a pcdna-ehcpadh vaccine against entamoeba histolytica elicits a protective th1-like response in hamster liver.dna vaccines are promising tools to fight parasitic diseases, including amoebiasis caused by the protozoan entamoeba histolytica. here we studied the immunogenicity and protective efficacy of a dna vaccine against this parasite composed by the ehcpadh surface complex encoding genes (ehcp112 and ehadh112). ehcpadh is formed by an adhesin (ehadh112) and a cysteine proteinase (ehcp112), both involved in the parasite virulence. we evaluated transcription, protein expression, immunological response a ...200919406180
attribution of malnutrition to cause-specific diarrheal illness: evidence from a prospective study of preschool children in mirpur, dhaka, bangladesh.we examined whether malnutrition (underweight [waz] < -2) increased the risk of diarrhea equally for all enteropathogens. the study was conducted prospectively between january 1999 and july 2002 in mirpur, an urban slum in dhaka. two hundred eighty-nine bangladeshi children (147 male and 142 female) 2-5 years of age were included in the study. malnutrition was present in 39% of the children at the time of enrollment. the parents and children were visited and interviewed every other day by health ...200919407131
a case of duodenal entamoeba histolytica. 200919410047
molecular diagnostics of intestinal parasites in returning travellers.a new diagnostic strategy was assessed for the routine diagnosis of intestinal parasites in returning travellers and immigrants. over a period of 13 months, unpreserved stool samples, patient characteristics and clinical data were collected from those attending a travel clinic. stool samples were analysed on a daily basis by microscopic examination and antigen detection (i.e. care as usual), and compared with a weekly performed multiplex real-time polymerase chain reaction (pcr) analysis on enta ...200919415354
trichomonas vaginalis: metronidazole and other nitroimidazole drugs are reduced by the flavin enzyme thioredoxin reductase and disrupt the cellular redox system. implications for nitroimidazole toxicity and resistance.infections with the microaerophilic parasite trichomonas vaginalis are treated with the 5-nitroimidazole drug metronidazole, which is also in use against entamoeba histolytica, giardia intestinalis and microaerophilic/anaerobic bacteria. here we report that in t. vaginalis the flavin enzyme thioredoxin reductase displays nitroreductase activity with nitroimidazoles, including metronidazole, and with the nitrofuran drug furazolidone. reactive metabolites of metronidazole and other nitroimidazoles ...200919415801
the nucleolus in entamoeba histolytica and entamoeba invadens is located at the nuclear periphery.the ribosomal rna genes in the human parasite entamoeba histolytica and its reptilian counterpart entamoeba invadens are located on extrachromosomal circles. the expression of rrna genes generally takes place in a specialized nuclear compartment-the nucleolus. in entamoeba species the nuclear space that may be called the nucleolus has yet to be defined. previous studies showed that the rdna circles are located at the nuclear periphery. here we have raised antibodies against the e. histolytica ho ...200919416742
[cryptosporidium sp infections and other intestinal parasites in food handlers from zulia state, venezuela].cryptosporidiosis in food handlers from venezuela is unknown, being this an important public health problem in immunosuppressed patients. to determine the prevalence of cryptosporidium sp and other intestinal parasites in food handlers from zulia state, one hundred nineteen fecal samples were evaluated by wet mount, concentrated according to ritchie and modified ziehl-neelsen staining. fourteen (11.8%) were positive for cryptosporidium sp and associated with other protozoosis (p < 0.05), being m ...200919418723
major cysteine peptidases of entamoeba histolytica are required for aggregation and digestion of erythrocytes but are dispensable for phagocytosis and cytopathogenicity.cysteine peptidases of entamoeba histolytica (ehcps) are considered to be important pathogenicity factors. it has been described that under standard axenic culture conditions, only three (ehcp-a1, ehcp-a2 and ehcp-a5) out of approximately 50 cysteine peptidase genes present in the e. histolytica genome are substantially expressed, thus representing the set of major ehcps. in this study, transcriptional silencing of the major peptidase genes was used to characterize their physiological role in mo ...200919426210
[autochthonous amebic liver abscess in spain: an emerging disease? case report and description of a pcr-based diagnostic test].in spain an increase in cases of amebiasis has been detected in patients with no history of traveling to, or immigration from, endemic areas.200919427082
natural killer t cells activated by a lipopeptidophosphoglycan from entamoeba histolytica are critically important to control amebic liver abscess.the innate immune response is supposed to play an essential role in the control of amebic liver abscess (ala), a severe form of invasive amoebiasis due to infection with the protozoan parasite entamoeba histolytica. in a mouse model for the disease, we previously demonstrated that jalpha18(-/-) mice, lacking invariant natural killer t (inkt) cells, suffer from more severe abscess development. here we show that the specific activation of inkt cells using alpha-galactosylceramide (alpha-galcer) in ...200919436711
insights into the mechanism of dna recognition by the methylated line binding protein ehmlbp of entamoeba histolytica.ehmlbp is an essential entamoeba histolytica protein that binds preferentially to methylated long interspersed nuclear elements and rdna. in an effort to identify more ehmlbp dna substrates, we developed an affinity-based technique in which the c-terminal dna binding domain of ehmlbp (gst-cterehmlbp) was used as the ligand. bioinformatic analysis of the dna sequences that were isolated by this affinity method revealed the presence of a 29-nucleotide consensus motif that includes a stretch of ten ...200919450728
nonpathogenic entamoeba dispar quickly outgrows pathogenic entamoeba histolytica in mixed xenic cultures.entamoeba histolytica and entamoeba dispar are two microscopically indistinguishable amoebae living in the human colon. the former is a pathogen, whereas the latter is a nonpathogenic commensal. using a model system of in vitro cocultures and pcr detection of the entamoeba species, we found that the nonpathogenic species can rapidly outgrow the pathogen in xenic cultures.200919187490
impact of solar radiation in disinfecting drinking water contaminated with giardia duodenalis and entamoeba histolytica/dispar at a point-of-use water treatment.to determine the impact of natural sunlight in disinfecting water contaminated with cysts of giardia duodenalis and entamoeba histolytica/dispar using plastic containers.200919191972
education and imaging. gastrointestinal: amebic colitis. 200919196401
recent discoveries in the pathogenesis and immune response toward entamoeba histolytica.entamoeba histolytica is an enteric dwelling human protozoan parasite that causes the disease amoebiasis, which is endemic in the developing world. over the past four decades, considerable effort has been made to understand the parasite and the disease. improved diagnostics can now differentiate pathogenic e. histolytica from that of the related but nonpathogenic entamoeba dispar, thus minimizing screening errors. classically, the triad of gal-lectin, cysteine proteinases and amoebapores of the ...200919207103
in-vitro cytotoxicity and antimicrobial activities, against clinical isolates of campylobacter species and entamoeba histolytica, of local medicinal plants from the venda region, in south africa.in the quest for alternative treatments against campylobacter jejuni and entamoeba histolytica, which are both aetiological agents of diarrhoea world-wide, the in-vitro activities against the two pathogens of extracts of 18 south african medicinal plants have recently been assessed. forty extracts from the 18 plant species were prepared and tested against 110 clinical isolates of campylobacter spp. in addition, extracts from eight of the plant species were tested against a standard strain (hm-1: ...200919208300
synthesis and in vitro trichomonicidal, giardicidal and amebicidal activity of n-acetamide(sulfonamide)-2-methyl-4-nitro-1h-imidazoles.two new series of imidazole derivatives (acetamides: 1-8 and sulfonamides: 9-15) were synthesized using a short synthetic route. compound 1 as well as the intermediate 16g were characterized by x-ray crystallography. imidazole derivatives 1-15 were tested in vitro against three unicellular parasites (giardia intestinalis, trichomonas vaginalis and entamoeba histolytica) in comparison with benznidazole (bzn) and metronidazole. compound 1 [n-benzyl-2-(2-methyl-4-nitro-1h-imidazol-1-yl)acetamide] w ...200919208443
using differential gene expression to study entamoeba histolytica pathogenesis.the release of the entamoeba histolytica genome has facilitated the development of techniques to survey rapidly and to relate gene expression with biology. the association and potential contribution of differential gene expression to the life cycle and the virulence of this protozoan parasite of humans are reviewed here.200919217826
[diarrhea from the infectologist's point of view].gastroenteritis is a nonspecific term for various pathologic states of the gastrointestinal tract. gastroenteritis causing pathogens are the second leading cause of morbidity and mortality worldwide. in the developed countries diarrhea is the most common reason for missing work, while in the developing world, it is a leading cause of death. internationally, the mortality rate is 5-10 million deaths each year. "traveller's diarrhea" is a polyetiologic common health problem of international travel ...200919218145
effects of iron depletion on entamoeba histolytica alcohol dehydrogenase 2 (ehadh2) and trophozoite growth: implications for antiamoebic therapy.the purpose of this study was to determine the mechanism by which iron chelation affects the trophozoite survival of entamoeba histolytica. fe2+ is a cofactor for e. histolytica alcohol dehydrogenase 2 (ehadh2), an essential bifunctional enzyme [alcohol dehydrogenase (adh) and aldehyde dehydrogenase (aldh)] in the glycolytic pathway of e. histolytica.200919218278
short hairpin rna-mediated knockdown of protein expression in entamoeba histolytica.entamoeba histolytica is an intestinal protozoan parasite of humans. the genome has been sequenced, but the study of individual gene products has been hampered by the lack of the ability to generate gene knockouts. we chose to test the use of rna interference to knock down gene expression in entamoeba histolytica.200919222852
entamoeba histolyticaehgef1 structure and mutational analysis: new specific residues critical for function.this paper reports the ehgef1-ehracg and ehgef1-ehrho1 molecular complexes from entamoeba histolytica. the not conserved amino acids gln201,tyr299, gln302, lys312, asn313, phe314 and ile324 were localized, by means of an in silico computational analysis, at the interface of the exposed face from the dh domain of ehgef1, which are important to establish the contact with its target gtpases ehracg and ehrho1. functional studies of nucleotide exchange of phe314ala mutant showed a decrement of 80% on ...200919135094
host-microbe interactions and defense mechanisms in the development of amoebic liver abscesses.summary: amoebiasis by entamoeba histolytica is a major public health problem in developing countries and leads to several thousand deaths per year. the parasite invades the intestine (provoking diarrhea and dysentery) and the liver, where it forms abscesses (amoebic liver abscesses [alas]). the liver is the organ responsible for filtering blood coming from the intestinal tract, a task that implies a particular structure and immune features. amoebae use the portal route and break through the sin ...200919136434
structural characterization of a novel ca2+-binding protein from entamoeba histolytica: structural basis for the observed functional differences with its isoform.a novel ca(2+)-binding protein (ehcabp2) was identified from the protozoan parasite entamoeba histolytica. ehcabp2 has 79% sequence identity with calcium-binding protein ehcabp1. the 3d structure of ehcabp2 was determined using multidimensional nuclear magnetic resonance spectroscopic techniques. the study reveals that the protein consists of two globular domains connected by a short flexible linker region of four residues. on comparison of the 3d structure and dynamics of ehcabp2 with those of ...200919137330
effects of dna damage induced by uv irradiation on gene expression in the protozoan parasite entamoeba histolytica.previously, we provided evidence for the role of e. histolytica rad52 epistasis group genes and the ehrad51 recombinase in dna damage response. to identify other genes participating in dna repair in this protozoan parasite, here we analyzed the transcriptional response to genetic damage induced by ultraviolet light (uv) using cdna microarrays. we found that 11.6% (350 orfs) and 17.2% (522 orfs) of genes were modulated at 5 min and 3h after uv irradiation, respectively. most genes were less than ...200919138709
improvement in detection of enterotoxigenic escherichia coli in patients with travelers' diarrhea by increasing the number of e. coli colonies tested.no cause of one-third of travelers' diarrhea (td) cases can be detected despite microbiologic assessment. we propose that these pathogen-negative td cases include undetected enterotoxigenic escherichia coli (etec). as a standard in diagnostic microbiology, samples of five e. coli colonies were tested to detect etec from stool cultures. we compared the sensitivities and the number of etec detected by 20 colonies with those of 5, 10, and 15 colonies. the percent detection of etec with five e. coli ...200919141833
two different chitinase genotypes in a patient with an amebic liver abscess: a case report.the present work deals with the identification of a patient with two liver abscesses containing two different strains of entamoeba histolytica, as defined by chitinase gene plymorphisms.200919141839
enteroparasitosis and their ethnographic relationship to food handlers in a tourist and economic center in paraná, southern brazil.this study reports on the occurrence of enteroparasites based on data from an ethnographic study of food handlers in the city of cascavel, paraná, brazil. fecal material from 343 food handlers of both sexes, between 14 and 75 years of age, was analyzed using lutz, modified ritchie and ziehl-neelsen techniques. ethnographic relationships were investigated by means of specific questionnaires. positive fecal samples were found for 131 (38.2%) handlers. endolimax nana (67.9%) was the predominant spe ...200919229388
microbiological and toxicological effects of perla black bean (phaseolus vulgaris l.) extracts: in vitro and in vivo studies.we investigated the microbiological and toxicological effects of three perla black bean extracts on the growth and culture of selected pathogenic microorganisms, the toxicity over vero cell lines and an in vivo rat model. three different solvents were used to obtain perla black bean extracts. all three perla black bean extracts were tested for antibacterial and antiparasitic activity and further analysed for intrinsic cytotoxicity (ic(50)). methanol perla black bean extract was used for acute to ...200919053992
the human antimicrobial protein psoriasin acts by permeabilization of bacterial membranes.psoriasin, a member of the s100 family of calcium-binding proteins (s100a7) is highly upregulated in the skin of psoriasis patients. as it has recently been found to exhibit antimicrobial activity, an important role of psoriasin in surface defence has been suggested. the similarity of the three-dimensional structures of psoriasin and amoebapore a, an ancient antimicrobial, pore-forming peptide from entamoeba histolytica, intrigued us to investigate whether the human psoriasin is also able to per ...200919162067
[detection and differentiation of entamoeba histolytica and entamoeba dispar by polymerase chain reaction in a community in zulia state, venezuela].differential identification of entamoeba histolytica and entamoeba dispar is essential for both appropriate patient treatment and epidemiological purposes. to determine the prevalence of these amoeba infections in santa rosa de agua (maracaibo, zulia state, venezuela), a pcr assay using specific primers for each species was standardized and applied. 204 stool samples were analyzed through direct microscopic examination with ssf (0.85%) and lugol, formol-ether concentration, and pcr. under direct ...200919180297
differential expression of surface glycoconjugates on entamoeba histolytica and entamoeba dispar.the human large intestine can harbor two morphologically similar amoebae; the invasive entamoeba histolytica and the non-invasive entamoeba dispar. whereas e. histolytica can produce intestinal and extra-intestinal lesions, e. dispar is present in non-symptomatic carriers. although biochemical, genetic and proteomic studies have identified clear differences between these entamoebae, it has become clear that several molecules, once assumed to be involved in tissue destruction, exist in both the v ...200919269346
horizontal gene transfer in eukaryotic parasites: a case study of entamoeba histolytica and trichomonas vaginalis.over the past few years it has become apparent that horizontal gene transfer (hgt) has played an important role in the evolution of pathogenic prokaryotes. what is less clear is the exact role that hgt has played in shaping the metabolism of eukaryotic organisms. the main problems are the reliable inference of hgt on a genomic scale as well as the functional assignment of genes in these poorly studied organisms. we have screened the completed genomes of the protists entamoeba histolytica and tri ...200919271203
[amebic meningoencephalitis].it has been reported that amebic meningoencephalitis is caused by some rhizopods, which are taxonomically different from entamoeba histolytica which is well known as the causative agent of amebic dysentery. different types of human meningoencephalitis have been reported to be caused by amphizoic amebae, which are not obligatorily parasitic (endozoic) but are usually free-living (exozoic) in nature, i.e., in environmental water and soil: naegleria fowleri causes acute primary amebic meningoenceph ...200919235460
a developmentally regulated myb domain protein regulates expression of a subset of stage-specific genes in entamoeba histolytica.conversion between a cyst and trophozoite stage is essential to disease transmission and pathogenesis in the parasitic protist entamoeba histolytica. a transcriptomic analysis of e. histolytica cysts and trophozoites has recently been accomplished, but the molecular basis of the regulation of encystation is not known. we have now identified a developmentally regulated myb protein (belonging to the shaqky family of myb proteins), which controls expression of a subset of amoebic stage-specific gen ...200919239479
hepatic amebiasis: a reminder of the complications.the complications of amebic liver abscess are underappreciated in developed countries and are often misdiagnosed. we report a 16-month-old male child with amebic liver abscess, initially misdiagnosed with pneumonia, who became critically ill with peritoneal, pleural and pericardial extension, and gastric perforation. in addition to highlighting the complications of amebic liver abscess, this case demonstrates the value of pcr testing as a diagnostic and molecular tool.200919242252
a retrospective analysis of prevalence of gastrointestinal parasites among school children in the palajunoj valley of guatemala.this study retrospectively analyzed demographic factors that may affect the prevalence of intestinal parasites among guatemalan school children. the findings of the study showed that young age, wet season, female gender, and severe malnutrition all correlated positively with increased rates of infection. clinical visits were performed on 10,586 school children aged 5-15 years over a four-year period (2004-2007) in the palajunoj valley of guatemala, during which 5,705 viable stool samples were sc ...200919248646
presence and diagnosis of amebic infestation in turkish patients with active ulcerative colitis.it is difficult to definitively diagnose acute amebiasis, particularly when this condition is superimposed on inflammatory bowel disease. our goals in this study were to determine the prevalence of amebiasis in individuals with active ulcerative colitis, and to identify clinical and laboratory parameters that are of value for diagnosing amebiasis in this patient group.200919712863
intestinal parasitic infections among inhabitants of karaj city, tehran province, iran in 2006-2008.karaj is an area with large influx of refugee people in iran. to increase knowledge about parasitic infections, we carried out this research during 2006-2008. we recorded the stool examination results and some of their personal characteristics. a total of 13,915 human stools were examined, and 649 (4.7%) were positive for intestinal parasites. among them, 13 (0.09%) had worm and 636 (4.6%) had protozoan infections. maximum infections belonged to giardia intestinalis, and 534 (3.8%) samples had t ...200919724700
a survey of intestinal protozoan infections among gastroenteritis patients during a 3-year period (2004-2006) in gyeonggi-do (province), south korea.the incidence and etiology of parasite-associated gastroenteritis during 2004-2006 in gyeonggi-do (province), south korea was determined by means of antigen detection elisa on 6,071 stool specimens collected from 6 general hospitals. at least 1 parasitic agent was detected in 3.4% (208/6,071) of the stool samples. among these, giardia lamblia was the most numerous (152 cases; 2.5%), followed by entamoeba histolytica (25 cases; 0.4%), cryptosporidium parvum (23 cases; 0.4%), and mixed infections ...200919724707
malnutrition and intestinal parasitic infections in school children of gondar, north west ethiopia.in developing countries, malnutrition is a considerable health problem with prevalence ranges of 4-46%, with 1-10% severely malnourished.200919743775
a rare but fatal case of granulomatous amebic encephalitis with brain abscess: the first case reported from turkey.the incidence of protozoal and helminthic infestations of the central nervous system (cns) is less than 1%, but these infestations tend to follow a fatal course. they are more common among children, the elderly and immunocompromised individuals. cns infections due to entamoeba histolytica have been known for a long time. in recent years, especially in developing countries, there has been an increase in cns infections due to free-living amebas (flas). acute cns infection due to naegleria fowleri, ...200919621290
prevalence of intestinal parasitosis in a rural population in egypt, and its relation to socio-demographic characteristics.a cross-sectional study was conducted in a village in menoufia governorate, egypt where the majority of people had individual trenches in the houses for sewage disposal with absence of public sewage system. out of 2292 stool samples 47.8% had at least a single infection. multiple infections occurred in 14.9%. entamoeba histolytica was 20%, e. coli 10%, giardia lamblia 10%, ascaris lumbricoides 27.31%, hymenolepis nana 2.96%, schistosoma mansoni 2.45% and ancylostoma duodenale 2.23%. males were s ...200919621655
[sensibility of entamoeba histolytica trophozoites to ivermectin].amebiasis caused by entamoeba histolytica is a problem of public world health. the most frequent clinical presentation are the dysentery and the amebic liver abscess. fifty millions of cases and more than 100.000 deaths for this disease are reported annually worldwide. the life cycle of e. histolytica has two phases: trophozoite and cyst. trophozoites are the causal agent of disease. the effective treatment for the amebiasis includes drugs with serious collateral effects. ivermectin is a macroli ...200919622479
parasitological diagnosis combining an internally controlled real-time pcr assay for the detection of four protozoa in stool samples with a testing algorithm for microscopy.molecular detection of gastrointestinal protozoa is more sensitive and more specific than microscopy but, to date, has not routinely replaced time-consuming microscopic analysis. two internally controlled real-time pcr assays for the combined detection of entamoeba histolytica, giardia lamblia, cryptosporidium spp. and dientamoeba fragilis in single faecal samples were compared with triple faeces test (tft) microscopy results from 397 patient samples. additionally, an algorithm for complete para ...200919624500
gonadectomy inhibits development of experimental amoebic liver abscess in hamsters through downregulation of the inflammatory immune response.incidence of amoebic liver abscess (ala) in human males is considerably higher than in females, suggesting a role for sex hormones in this parasite infection. we describe here the effect of hamster gonadectomization on the development of ala. after monitoring the decrease of oestradiol in females and testosterone in males to undetectable levels by elisa and radio immuno assay (ria) in serum, hamsters were intraportally infected with entamoeba histolytica trophozoites and killed 7 days later. ala ...200919646209
entamoeba invadens: cloning and molecular characterization of chitinases.entamoeba histolytica, the causative agent of amebiasis infects through its cyst form and this transmission may be blocked using encystation specific protein as drug target. in this study, we have characterized the enzyme chitinase which express specifically during encystation. the reptilian parasite entamoeba invadens, used as a model for encystation study contain three chitinases. we report the molecular cloning, over-expression and biochemical characterization of all three e. invadens chitina ...200919646441
comparison of two genetically related entamoeba histolytica cell lines derived from the same isolate with different pathogenic properties.entamoeba histolytica is known for its extraordinary capacity to destroy human tissues, leading to invasive diseases such as ulcerative colitis or extra-intestinal abscesses. in order to identify the virulence factors of this parasite phenotypes and proteomes of two recently identified genetically related cell lines (a and b), derived from the laboratory e. histolytica isolate hm-1:imss, were compared. both cell lines are indistinguishable on the basis of highly polymorphic tandem repeat dna seq ...200919688750
in vitro activity of pyrvinium pamoate against entamoeba histolytica and giardia intestinalis using radiolabelled thymidine incorporation and an sybr green i-based fluorescence assay.to assess the in vitro activity of the fda-approved antihelminthic drug pyrvinium pamoate against entamoeba histolytica and giardia intestinalis.200919689977
opportunistic parasitic infections in hiv/aids patients presenting with diarrhoea by the level of immunesuppression.enteric parasites are major cause of diarrhoea in hiv infected individuals. the present study was undertaken to detect enteric parasites in hiv infected patients with diarrhoea at different levels of immunity.200919700803
new synthesis and antiparasitic activity of model 5-aryl-1-methyl-4-nitroimidazoles.a number of 5-aryl-1-methyl-4-nitroimidazoles 5a-f have been synthesized in good yields by the suzuki coupling reaction between 5-chloro-1-methyl-4-nitroimidazole (3) and arylboronic acids 4a-f, aided by dichlorobis-(triphenylphosphine)palladium(ii), k(2)co(3, )and tetrabutylammonium bromide in water at 70-80 degrees c. compounds 5a-f were characterized by elemental analysis, nmr and ms spectral data. on the basis of in vitro screening data, 5-(3-chlorophenyl)-1-methyl-4-nitro-1h-imidazole (5f) ...200919701122
diagnosis and treatment of acute or persistent diarrhea.studies of microbial pathogens and the toxins they produce are important for determining the mechanisms by which they cause disease and spread throughout a population. some bacteria produce secretory enterotoxins (such as cholera toxin or the heat-labile or stable enterotoxins produced by escherichia coli) that invade cells directly. others invade cells or produce cytotoxins (such as those produced by shigella, enteroinvasive e coli, or clostridium difficile) that damage cells or trigger host re ...200919457416
dna characterization of simian entamoeba histolytica-like strains to differentiate them from entamoeba histolytica.two simian entamoeba histolytica-like strains, ehmfas1 and p19-061405, have been suggested to represent a new species based on genetic characterization. sequence analyses of the hexokinase, glucose phosphate isomerase, and phosphoglucomutase genes supported the previous findings of isoenzyme analyses demonstrating a new zymodeme pattern. phylogenetic studies of 18s rdna, 5.8s rdna, the chaperonin 60 gene, and the pyridine nucleotide transhydrogenase gene showed original clusters of simian e. his ...200919471966
high early mortality in patients with chronic acquired immunodeficiency syndrome diarrhea initiating antiretroviral therapy in haiti: a case-control study.this case-control study examines whether chronic diarrhea at initiation of antiretroviral therapy (art) affects survival of human immunodefiency virus-infected patients. cases (288) were treatment-naive, non-pregnant, adults with self report of frequent loose stool for > 3 weeks at the time art was initiated. one-third of patients had an enteric pathogen identified including cryptosporidium spp., giardia spp., isospora belli, cyclospora cayetanensis, and entamoeba histolytica. control patients ( ...200919478276
involvement of serine proteases in the excystation and metacystic development of entamoeba invadens.although the functions of cysteine proteases involved in the pathogenicity and differentiation of entamoeba histolytica have been demonstrated, little is known about the functions of serine proteases. we examined the involvement of serine proteases in amoebic excystation and metacystic development using inhibitors specific for serine proteases. entamoeba invadens ip-1 strain was used as the model of excystation and metacystic development of e. histolytica. four serine protease inhibitors, phenyl ...200919479279
an alternative method for dna extraction and pcr identification of entamoeba histolytica and e. dispar in fecal samples.since it is known that entamoeba dispar is non-pathogenic and morphologically similar to e. histolytica, there are many targets used in pcr for differentiating these species. however, obtaining high quality dna from fecal samples is fundamental for pcr. most methods are laborious or use kits that make diagnosis expensive. in the present work, a new simple, fast and cheap technique of dna extraction from fecal samples was combined with a pcr for an episomal target in order to identify e. histolyt ...200919486545
[the complicated intestinal amebiasis in emergency surgery].18 patients with complicated forms of intestinal amebiasis were operated on acute appendicitis, liver abscess or total necrotic colitis. appendectomy, abscess drainage and colon resection were performed respectively. there were no postoperative deaths. features of amebic appendicitis and total necrotic amebic colitis are described using clinical cases demonstrations. recommendations for the treatment of these forms of amebiasis are given.200919491760
phosphatidylinositol-phosphates mediate cytoskeletal reorganization during phagocytosis via a unique modular protein consisting of rhogef/dh and fyve domains in the parasitic protozoon entamoeba histolytica.to understand the roles of phosphoinositides [ptdins] in phagocytosis of parasitic eukaryotes, we examined the interaction of phosphatidylinositol-3-phosphate [ptdins(3)p] and putative ptdins-p-binding proteins during phagocytosis in the enteric protozoan parasite entamoeba histolytica. it was previously shown that phagocytosis in e. histolytica is indispensable for virulence and is inhibited by ptdins 3-kinase inhibitors. we demonstrated by time-lapse live imaging that during the initiation of ...200919496789
periodicity and patterns of entamoeba histolytica and e. dispar infection in hiv+/aids patients in mexico.in a 12-month longitudinal study, a cohort of mexican hiv+/aids patients was checked several times for entamoeba infection, with the parasites identified, as e. histolytica or e. dispar, using pcr. the polymorphic region of the parasites' chitinase genes was investigated by pcr, with the variation in amplicon sizes being used as a measure of the genetic variation among the isolates. the patients found infected with entamoeba at the start of the study displayed varied patterns of infection cleara ...200919508748
entamoeba histolytica, heterologous expression and in situ immunolocalization of ornithine decarboxylase (ehodc).previous studies from this laboratory have dealt with the purification and biochemical characterization of ornithine decarboxylase (odc) from entamoeba histolytica. enzyme compartmentalization has been described as a major mechanism in the regulation of polyamine metabolism. however, the subcellular location of odc in the human parasite has remained unresolved. to examine this issue, we cloned the full-length gene (ehodc) encoding for the parasite enzyme, whose open reading frame encodes for a p ...200919520076
high genetic diversity among iranian entamoeba dispar isolates based on the noncoding short tandem repeat locus d-a.this study has identified and characterized the structure of locus d-a, a noncoding short tandem repeat (str) region, also known as locus 1-2, in iranian entamoeba dispar isolates. this polymorphic locus has been shown to be potentially useful in investigating the molecular epidemiology of entamoeba histolytica and e. dispar. the genetic polymorphisms in locus d-a in 28 isolates of e. dispar from three different geographic regions of iran were distinguished using pcr and sequencing, and the resu ...200919524081
concurrent infections and socioeconomic determinants of geohelminth infection: a community study of schoolchildren in periurban guinea-bissau.we explored the association between subclinical intestinal helminth infections and other gastrointestinal pathogens in 706 schoolchildren from a poor semirural area while adjusting for socioeconomic risk factors. the study was carried out in two neighbouring areas in the capital of guinea-bissau in west africa. children aged 4-12 years were visited and one child per mother was invited to participate in the study. among the 706 children included in the study, helminths were detected in 44.2%, ent ...200919524992
use and endocytosis of iron-containing proteins by entamoeba histolytica trophozoites.iron is essential for nearly all organisms; in mammals, it is part of proteins such as haemoglobin, and it is captured by transferrin and lactoferrin. transferrin is present in serum, and lactoferrin is secreted by the mucosa and by neutrophils at infection sites, as a host iron-withholding response, sequestering iron away from invading microorganisms. additionally, all cells contain ferritin, which sequesters iron when its intracellular levels are increased, detoxifying and preventing damage. l ...200919539057
reassessment of the epidemiology of amebiasis: state of the art.the epidemiology of amebiasis has dramatically changed since the separation of entamoeba histolytica and entamoeba dispar species, and the worldwide prevalence of these species has not been estimated until recently. the most cited data regarding prevalence, morbidity, or mortality due to amebiasis is the 1986 walsh report, in which 100,000 deaths are reported to occur worldwide each year due to medical complications of invasive amebiasis. however, the prevalence values of entamoeba histolytica i ...200919540361
[remarkable evolution of hepatic, pleural and pulmonary amoebiasis: a case report].entamoeba histolytica, is a human pathogen which is endemic in tropical areas. the most common extra-intestinal locations for disease after the liver are pleural and pulmonary. although the outcome of pleural and pulmonary amoebiasis is generally favourable, it is important to note that a significant proportion of patients do develop pleural and pulmonary after-effects. we report a case of pleural and pulmonary amoebiasis where the evolution of a massive pleural effusion and 3 associated liver a ...200919543174
[tinidazole: a classical anaerobical drug with multiple potential uses nowadays].tinidazole is a 5-nitroimidazole active in vitro against a wide variety of anaerobic bacteria and protozoa. tinidazole is an effective treatment against anaerobic microorganisms based on its pharmacokinetic characteristics (c(max) 51 microg/ml, t(1/2) 12.5 h) and its excellent in vitro activity. its long half-life allows once a day regimens. tinidazole is as effective as metronidazole in the treatment of infections caused by t. vaginalis, giardiasis and amebiasis and bacterial vaginosis, malaria ...200919544102
hospital-based surveillance of enteric parasites in kolkata.diarrhoea is the second leading cause of illness and death in developing countries and the second commonest cause of death due to infectious diseases among children under five in such countries. parasites, as well as bacterial and viral pathogens, are important causes of diarrhoea. however, parasitic infections are sometimes overlooked, leading after a period of time to an uncertain aetiology. in this paper we report the prevalence of giardia lamblia, entamoeba histolytica and cryptosporidium sp ...200919545355
protection against intestinal amebiasis by a recombinant vaccine is transferable by t cells and mediated by gamma interferon.we have previously shown that vaccination with purified entamoeba histolytica gal/galnac lectin or recombinant subunits can protect mice from intestinal amebiasis upon intracecal challenge. in this study, we demonstrated with adoptive-transfer experiments that this lectin vaccine protection is mediated by t cells but not serum. the cell-mediated immune (cmi) response was characterized by significant gamma interferon (ifn-gamma), interleukin 12 (il-12), il-2, il-10, and il-17 production. to move ...200919564375
cell-free synthesis and combinatorial selective 15n-labeling of the cytotoxic protein amoebapore a from entamoeba histolytica.amoebapore a is a pore-forming protein produced by the pathogenic parasite entamoeba histolytica, which causes human amoebic dysentery. the pore-forming activity of amoebapore a is regulated by ph-dependent dimerization, a prerequisite for membrane insertion and pore formation. understanding of these important processes has been hampered by the cytotoxicity of amoebapore a, which prevents the production of this protein in cell-based expression systems. in this study, a protocol for the cell-free ...200919573603
intestinal amoebiasis in children and its effect on nutritional status.to determine the frequency and clinical presentation of amoebic diarrhea in children and its effect on the nutritional status of the affected children.200919576153
physical, structural, and functional properties of the beta1 integrin-like fibronectin receptor (beta1ehfnr) in entamoeba histolytica.the presence in entamoeba histolytica of a fibronectin (fn) receptor, which is antigenically related to beta1 integrin-like molecules and shows 99% homology with the intermediate subunit-2 of the gal/galnac-specific lectin has been described. the e. histolytica genome has been sequenced, and its analysis shows no integrin sequences. here we provide further evidence to demonstrate that this molecule behaves as integrin-like in its physical, structural and functional properties. the purified beta1 ...200919577014
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