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[re-staining of the slides of entamoeba histolytica trophozoites]. 200415830894
immunization with a tetramer derivative of an anti-inflammatory pentapeptide produced by entamoeba histolytica protects gerbils (meriones unguiculatus) against experimental amoebic abscess of the liver.axenically grown entamoeba histolytica produces a pentapeptide (met-gln-cys-asn-ser) with several anti-inflammatory properties, including the inhibition of human monocyte locomotion (monocyte locomotion inhibitory factor (mlif)). a construct displays the same effects as the native material. it remains to be seen if mlif is used, or even produced in vivo by the tissue-invading parasite. if mlif were to be relevant in invasive amoebiasis, immunizing against it could diminish this parasite advantag ...200415679631
survey for intestinal parasites in belize, central america.a stool survey was carried out in 5 villages in the toledo district of the central american country of belize. eighty-two percent of a total population of 672 participated. the stools were examined by the formalin-ethyl-acetate concentration technique. sixty-six percent of the population was found to have one or more intestinal parasites. the most common infection was hookworm (55%) followed by ascaris lumbricoides (30%), entamoeba coli (21%), trichuris trichiura (19%), giardia lamblia (12%), io ...200415689057
detection of entamoeba histolytica/entamoeba dispar in stool specimens by using enzyme-linked immunosorbent assay.entamoeba histolytica actually comprises two genetically distinct but morphologically indistinguishable species. e. histolytica can cause invasive intestinal and extra intestinal disease, while e. dispar cannot. identification and differentiation of e. dispar and e. histolytica in stool sample by microscopy is imprecise. several weeks of culture and isoenzyme analysis are required to differentiate e. histolytica from e. dispar. in this study, we have used an enzyme-linked immunosorbent assay (el ...200415654437
detection of iga anti-entamoeba histolytica in the patients' saliva.e. histolytica is a protozoan parasite with worldwide distribution. the diagnosis of this parasite still depends on the microscopic examination. determination of the siga in the different body fluid proves to be of diagnostic value in many pathogens. to find out the potentials of salivary siga in diagnosis of intestinal amoebiasis, 30 patients with parasitologic proved e. histolytica and 30 cross-matched negative controls were selected for levels of salivary siga using radial immunodiffuion tech ...200415658064
prevalence of parasitic diseases among nomadic fulanis of south-eastern nigeria.a study was carried out to determine the prevalence of parasitic infections among the nomadic fulanis of south-eastern nigeria between september 2003-march 2004. urine, stool and blood specimens were collected from each of 231 subjects. of these, 98 (42.4%) were infected with one or more of 14 parasitic species, of which plasmodium malariae had the highest prevalence (15.3%). others included 6 intestinal helminth parasites: ascaris lumbricoides, hookworm, strongyloides stercoralis, schistosoma m ...200415627328
characterization of two long vesicle-associated membrane proteins or longins genes from entamoeba histolytica.this study characterizes two long vesicle-associated membrane protein (vamp) genes (sybl-1 and sybl-2) obtained from dna of entamoeba histolytica by pcr amplification. (nucleotide sequences of the entamoeba histolytica sybl-1 and sybl-2 genes appear in the genebank under accession numbers ay256852 and ay309014.)200415610906
entamoeba histolytica: correlation of assessment methods to measure erythrocyte digestion, and effect of cysteine proteinases inhibitors in hm-1:imss and hk-9:nih strains.entamoeba histolytica trophozoites are able to degrade human erythrocytes; the loss of erythrocyte cellular matrix and degradation of plasma membrane were observed, along with the decrease in the average size of digestive vacuoles. ninety-six percent of hemoglobin ingested was hydrolyzed by trophozoites within 3h, as evidenced by electrophoresis. accordingly, x-ray spectroscopy revealed the presence of iron inside vacuoles after erythrophagocytosis, the concentration of which decreased to contro ...200415582505
amebic liver abscess with bacterial superinfection in a patient with no epidemiologic risk factors.the amebic liver abscess is uncommon in developed countries like spain, but the incidence is increasing probably due to the migratory movements of the population. we report a case of an amebic abscess, initially unsuspected due to the absence of epidemiologic risk factors and the negative serology for amebiasis, in the early stages of the disease.200415584853
status of intestinal parasite infections among children in bat dambang, cambodia.a survey was conducted to determine the extent of intestinal parasite infection in bat dambang, cambodia in march 2004. a total of 623 fecal specimens was collected from kindergarten and schoolchildren and examined using the formalin-ether sedimentation technique. the overall infection rate of intestinal parasites was 25.7% (boys, 26.2%; girls, 25.1%), and the infection rates of intestinal helminthes by species were as follows: echinostoma sp. 4.8%, hookworm 3.4%, hymenolepis nana 1.3%, and rhab ...200415591838
ultrastructural observation of human neutrophils during apoptotic cell death triggered by entamoeba histolytica.neutrophils are important effector cells against protozoan extracellular parasite entamoeba histolytica, which causes amoebic colitis and liver abscess in human beings. apoptotic cell death of neutrophils is an important event in the resolution of inflammation and parasite's survival in vivo. this study was undertaken to investigate the ultrastructural aspects of apoptotic cells during neutrophil death triggered by entamoeba histolytica. isolated human neutrophils from the peripheral blood were ...200415591839
in vitro activity of azithromycin and dirithromycin against axenic entamoeba histolytica. 200415599659
in vitro activity of antiamoebic drugs against clinical isolates of entamoeba histolytica and entamoeba dispar.amoebiasis is a major public health problem in tropical and subtropical countries. although a number of antiamoebic agents are used for its treatment, yet the susceptibility data on clinical isolates of entamoeba histolytica and entamoeba dispar are not available. therefore, the present study was aimed to assess the in vitro susceptibility of clinical isolates of e. histolytica and e. dispar to metronidazole, chloroquine, emetine and tinidazole.200415610563
[outbreak of amoebiasis in a dutch family; tropics unexpectedly nearby].an amoebic liver abscess, amoebic dysentery and asymptomatic cyst passage were diagnosed in a father, a mother and one of their three children, respectively. one of the other children had been in the tropics, but only after the father's symptoms had begun. all three family members were infected with the same strain of entamoeba histolytica as determined by polymerase chain reaction (pcr)-based dna typing. the source of infection was most probably in southern italy where the family regularly spen ...200415495513
double-stranded rna mediates homology-dependent gene silencing of gamma-tubulin in the human parasite entamoeba histolytica.approaches that eliminate mrna are a powerful tool for reverse genetics applications in eukaryotic microbes for which gene replacement techniques have not yet been developed. here, for the first time, we demonstrate that rna duplexes efficiently inhibit gene expression when introduced into the human parasite entamoeba histolytica. chemically synthesized, small interfering rna (sirna) were highly specific and efficient in silencing parasite gamma-tubulin mrna. use of specific antibodies revealed ...200415500912
comparison of pcr and antigen detection methods for diagnosis of entamoeba histolytica infection.to assess different laboratory methods for the identification of entamoeba histolytica in clinical samples.200415563665
amebae and ciliated protozoa as causal agents of waterborne zoonotic disease.the roles free-living amebae and the parasitic protozoa entamoeba histolytica and balantidium coli play as agents of waterborne zoonotic diseases are examined. the free-living soil and water amebae naegleria fowleri, acanthamoeba spp., and balamuthia mandrillaris are recognized etiologic agents of mostly fatal amebic encephalitides in humans and other animals, with immunocompromised and immunocompetent hosts among the victims. acanthamoeba spp. are also agents of amebic keratitis. infection is t ...200415567581
ameboma in ultrasound-guided fine needle aspiration. 200415581177
energetics and mechanism of ca2+ displacement by lanthanides in a calcium binding protein.the displacement of ca(2+) by trivalent lanthanide ions (tm(3+)) in a protozoan (entamoeba histolytica) ca(2+) binding protein has been studied by nmr and isothermal calorimetry (itc). the study provides a basis for understanding the behavior of lanthanides when used as a substitute for ca(2+), the pattern of sequential binding, the structural changes involved, the range and magnitude of paramagnetic interaction, and the associated energetics and mechanism. the progressive ca(2+) displacement fr ...200415260475
cysteine proteinase activity is required for survival of the parasite in experimental acute amoebic liver abscesses in hamsters.axenic trophozoites of entamoeba histolytica strain hm1-imss grown in vitro in the presence of e-64, a potent irreversible inhibitor of cysteine proteinases, preserved their viability, their rate of replication, their resistance to complement, their haemolytic capacity and their ability to destroy target cells, despite complete inhibition of total cysteine proteinase activity. on the other hand, their erythrophagocytic capacity and their ability to decrease ter of mdck cells was partially decrea ...200415267108
low sensitivity of ultrasonography for the early diagnosis of amebic liver abscess. 200415464710
an experimental model for amoebic abscess production in the cheek pouch of the syrian golden hamster, mesocricetus auratus.a new experimental model was developed in hamsters for amoebic abscess caused by entamoeba histolytica. e. histolytica trophozoites were cultured in a liquid axenic medium, and then injected intradermally into the cheek pouch of the syrian golden hamster, mesocricetus auratus. inoculation consistently resulted in abscess formation at the site in 20 of 22 (91%) study animals. the amoebic nature of the abscesses was confirmed by light microscopy and histopathologic examination. abscess formation w ...200415468532
dynamics of endocytic traffic of entamoeba histolytica revealed by confocal microscopy and flow cytometry.entamoeba histolytica, the protozoan parasite of humans, manifests constitutive endocytosis to obtain nutrients and, when induced to express invasive behavior, as a means of ingesting and processing host cells and tissue debris. e. histolytica trophozoites were grown in liquid axenic medium that contained fluorescently labeled fluid-phase markers, so that the kinetics of uptake, the transit of loaded endosomes through the cytoplasm, and the time of release of the markers could be monitored by fl ...200415476263
molecular and phylogenetic characterization of syntaxin genes from parasitic protozoa.vesicular transport is an integral process in eukaryotic cells and the syntaxins, a member of the snare protein superfamily, are a critical piece of the vesicular transport machinery. we have obtained syntaxin homologues from diverse protozoan parasites (including entamoeba, giardia, trichomonas and trypanosoma), determined the paralogue affinity of the homologues by molecular phylogenetics and compared functionally critical amino acid sites identified in other syntaxins. surprisingly, three seq ...200415478792
kinetic mechanism and metabolic role of pyruvate phosphate dikinase from entamoeba histolytica.the kinetic mechanism and the metabolic role of pyruvate phosphate dikinase from entamoeba histolytica were investigated. the initial velocity patterns in double reciprocal plots were parallel for the phosphoenolpyruvate/amp and phosphoenolpyruvate/pyrophosphate substrate pairs and intersecting for the amp/pyrophosphate pair. this suggests a kinetic mechanism with two independent reactions. the rate of atp synthesis at saturating and equimolar concentrations of phosphoenolpyruvate, amp, and pyro ...200415485834
entamoeba histolytica cysteine protease 2 (ehcp2) modulates leucocyte migration by proteolytic cleavage of chemokines.human amoebiasis is a disease produced by infection with the protozoan entamoeba histolytica currently affecting many millions of people worldwide. amoebic colitis is the most common clinical manifestation. host protective immunity involves participation of both humoral and cellular responses. however, the mechanisms involved in immune evasion are not clear and remain under investigation. one of these mechanisms could be associated with the ability of parasite proteases to modulate or interfere ...200415491473
entamoeba histolytica: cdnas cloned as 30kda collagen-binding proteins (cbp) belong to an antioxidant molecule family. protection of hamsters from amoebic liver abscess by immunization with recombinant cbp.a cdna expression library of entamoeba histolytica was screened with antiserum to native amoebic collagen binding proteins (cbps), and two clones c13 and c7 which partially encode for the 30 kda cbp were obtained. the sequenced clones were 90% homologous. c7 had a 69 bp deletion at the 5' end that is present in c13 and encodes for a glu-cys-lys rich region and a four amino acids repeat (glu-lys-glu-cys). purified fusion proteins from these cdna clones were able to bind native type i collagen gel ...200415491543
epidemiological survey of the prevalence of parasites among children in khan younis governorate, palestine.the prevalence of intestinal parasites was determined for 1,370 children in khan younis governorate, gaza strip. the age of the children ranged from 6 to 11 years. for stool samples, inspection, direct smear microscopy, flotation and sedimentation techniques were used. the general prevalence of intestinal parasites was 34.2%. different types of intestinal parasites were detected during this survey: ascaris lumbricoides seemed to be the most common parasite (12.8%), whereas giardia lamblia had a ...200415517386
an improved pcr-based method for detection and differentiation of entamoeba histolytica and entamoeba dispar in formalin-fixed stools.detection of infectious agents in faecal samples by polymerase chain reaction (pcr) can be limited by the presence of substances which inhibit dna amplification. here, an improved protocol is reported for directly isolating dna from fresh and aged formalin-fixed stools, after concentration by formalin-ethyl acetate (fea). the protocol was successfully applied to detect dna of entamoeba histolytica/entamoeba dispar complex in stools by nested pcr, showing high specificity and low detection limit. ...200415533298
ancient weapons for attack and defense: the pore-forming polypeptides of pathogenic enteric and free-living amoeboid protozoa.pore-forming polypeptides have been purified from several amoeboid protozoans that are well-known human pathogens. obligate enteric parasites, such as entamoeba histolytica, and free-living but potentially highly pathogenic species, such as naegleria fowleri, contain these cytolytic molecules inside cytoplasmic granules. comprehensive functional and structural studies have been conducted that include isolation of the proteins from their natural sources, monitoring of their biological activity to ...200415537085
improved affinity of a human anti-entamoeba histolytica gal/galnac lectin fab fragment by a single amino acid modification of the light chain.we previously produced, in escherichia coli, a human monoclonal antibody fab fragment, cp33, specific for the galactose- and n-acetyl-d-galactosamine-inhibitable lectin of entamoeba histolytica. to prepare antibodies with a higher affinity to the lectin, recombination pcr was used to exchange ser91 and arg96 in the third complementarity-determining region of the light chain with other amino acids. the screening of 200 clones of each exchange by an indirect fluorescent antibody test showed that 1 ...200415539510
distribution of entamoeba histolytica gal/galnac lectin-specific antibody response in an endemic area.to demonstrate the dynamics of specific antibody isotypes against entamoeba histolytica gal/galnac adhesin and its correlation, if any, with the development of immunity, we evaluated subjects suffering from a spectrum of amoebic infections ranging from amoebic liver abscess (ala) to asymptomatic cyst passers. the quantitative analysis of antibody levels was done in the sera by enzyme-linked immunosorbent assay. gal/galnac adhesin-specific immunoglobulin g (igg) was higher in ala (and their follo ...200415541046
[autochthonous amebiasis in spain. endemic or emergent disease]. 200415546526
laparoscopic marsupialization of a giant posttraumatic splenic cyst.nonparasitic cysts are rare clinical lesions of the spleen. causes include congenital malformations and trauma. historically, management has entailed partial or total splenectomy using an open approach. recently, laparoscopic approaches have been developed. in this report, we describe laparoscopic marsupialization of a giant splenic cyst (diameter > 15 cm).200415554287
molecular characterization of peroxiredoxin from entamoeba moshkovskii and a comparison with entamoeba histolytica.peroxiredoxin of the pathogenic parasite, entamoeba histolytica, is thought to be involved in protection from oxidative attack by host phagocytic cells and endogenously generated hydrogen peroxide. in this study, we cloned peroxiredoxin genes from the nonpathogenic ameba, entamoeba moshkovskii, and characterized the peroxiredoxin protein. the open reading frame of three cloned cdnas was demonstrated to encode a polypeptide of 218 or 217 amino acids. identity of the amino acid sequence of peroxir ...200415555731
histone acetyltransferases and deacetylase in entamoeba histolytica.in our efforts to understand how transcription may be regulated in entamoeba histolytica, we have examined if this parasite has conserved enzymatic mechanisms for targeted acetylation and deacetylation of histones. western blotting indicated that basic nuclear proteins in the size range of 16-23 kda were acetylated in amebic trophozoites, suggesting histone acetylation. single representatives of the gnat and myst family of histone acetyltransferases (hats) were identified in the e. histolytica g ...200415555732
the beta-n-acetylhexosaminidase of entamoeba histolytica is composed of two homologous chains and has been localized to cytoplasmic granules.we have purified a beta-n-acetylhexosaminidase from trophozoites of entamoeba histolytica to homogeneity. in sds-page, the enzyme yielded a single protein band at an apparent m(r) of 64,000. the elution behaviour of the native enzyme upon molecular sieve chromatography corresponded to a molecular mass of approximately 132,000 suggesting that the enzyme is a dimer. upon sedimentation velocity centrifugation, hexosaminidase activity sedimented at 12s, implying aggregation to a higher molecular mas ...200415555733
oral vaccination with recombinant yersinia enterocolitica expressing hybrid type iii proteins protects gerbils from amebic liver abscess.protection against invasive amebiasis was achieved in the gerbil model for amebic liver abscess by oral immunization with live attenuated yersinia enterocolitica expressing the entamoeba histolytica galactose-inhibitable lectin that has been fused to the yersinia outer protein e (yope). protection was dependent on the presence of the yope translocation domain but was independent from the antibody response to the ameba lectin.200415557659
intestinal parasitic infections and micronutrient deficiency: a review.malnutrition including vitamin a and iron deficiency and parasitic diseases have a strikingly similar geographical distribution with the same people experiencing both insults together for much of their lives. parasitic infections are thought to contribute to child malnutrition and micronutrient deficiency through subtle reduction in digestion and absorption, chronic inflammation and loss of nutrients. parasites may affect the intake of food; it's subsequent digestion and absorption, metabolism a ...200415559182
comparative evaluation of hexokinase isoenzyme typing and antigen detection for differentiation of entamoeba histolytica and entamoeba dispar.entamoeba histolytica, the causative organism of invasive amebiasis is a potential pathogen, while asymptomatic infection is caused by e. dispar. differentiation of the species is not possible on the basis of morphological characters by microscopic examination. in the present study an attempt has been made to differentiate e. histolytica from e. dispar in 45 isolates obtained from culture and direct stool samples respectively on the basis of hexokinase isoenzyme analysis and tech lab elisa. a 10 ...200416295743
important zoonotic intestinal protozoan parasites in asia.intestinal protozoa are increasingly being studied because of their association with acute and chronic diarrhoea in immunocompromised as well as immunocompetent patients. various community outbreaks due to contamination of water or food with these protozoa have further highlighted their importance in public health. among these important pathogens are giardia duodenalis, entamoeba histolytica, cryptosporidium parvum, cyclospora cayetanensis, isospora belli, and microsporidia. except for the cyst- ...200416493397
proteinases in naegleria fowleri (strain nf3), a pathogenic amoeba: a preliminary study.naegleria fowleri is a free-living amoeba, known as a causative agent for a fatal disease of the central nervous system (cns) in man such as primary amoebic meningoencephalitis (pam). factors contributing to its pathogenicity and its distribution in the environment have been investigated by previous researchers. in case of its pathogenicity, several enzymes such as phospolipase a and sphingomyelinase, have been proposed to probably act as aggressors in promoting pam but no study so far have been ...200416493399
brain abscess due to entamoeba histolytica.a patient of cerebral amoebiasis due to entamoeba histolytica with no evidence of disease elsewhere is described. he made a complete recovery after surgical excision of the abscess along with metronidazole therapy.200415636321
serpins in unicellular eukarya, archaea, and bacteria: sequence analysis and evolution.most serpins irreversibly inactivate specific serine proteinases of the chymotrypsin family. inhibitory serpins are unusual proteins in that their native structure is metastable, and rapid conversion to a relaxed state is required to trap target enzymes in a covalent complex. the evolutionary origin of the serpin fold is unresolved, and while serpins in animals are known to be involved in the regulation of a remarkable diversity of metabolic processes, the physiological functions of homologues f ...200415638455
gastrointestinal parasites of the guenons of western uganda.from january 1998 to december 2002, we collected 293 fecal samples from free-ranging individuals of the 4 guenon species of western uganda, i.e., redtail guenons (cercopithecus ascanius), blue monkeys (cercopithecus mitis), l'hoesti monkeys (cercopithecus lhoesti), and vervet monkeys (cercopithecus aethiops), to quantify the prevalence of gastrointestinal parasites. helminth eggs, larvae, and protozoan cysts were isolated by sodium nitrate flotation and fecal sedimentation. helminth parasites we ...200415715228
[prevalence of infection by intestinal parasites in north lebanon: 1997-2001].we determined the prevalence of intestinal parasites in the north of lebanon between 1997 and 2001. we analysed the parasitology records of 17126 patients and evidence of parasitic infections was found in 5 713 (33.35%) cases. there was no significant difference in prevalence for males or females for any of the parasites. the most prevalent parasites were entamoeba coli (38.45%), ascaris lumbricoides (37.14%), giardia lamblia (15.39%), ent. histolytica (4.57%) and taenia sp. (3.3%). a comparison ...200416212211
cryptosporidium parvum and other instestinal parasites among diarrhoeal patients referred to ehnri in ethiopia.the occurrence of intestinal parasites in patients referred to the parasitology laboratory of the ethiopian health and nutrition research institute (ehnri), was recorded for four consecutive years, 1998-2001. based on the stool appearance i.e. watery, loose, muciod and bloody, 442 diarrhoeal samples were particularly selected to allow diagnosis of intestinal parasites with emphasis on coccidian intestinal parasites. wet saline mounts and formol ether concentration method with logul's iodine were ...200416895037
anemia, parasitic infections and some risk factors among physical education female students in alexandria.the present study was a cross-sectional one, carried out to estimate the percentages of anemia and parasites among students of faculty of physical education for girls and some of their related factors. a predesigned questionnaire was completed by the researchers through face-to-face meetings to collect data concerning age, menstruation history and some dietary habits. blood samples were taken by finger pricks to estimate hemoglobin (hb) concentration level (gm/dl). stool samples were collected a ...200317265613
a cross-sectional study of intestinal parasitic infections in a rural district of west china.parasitic infections are widespread in rural areas of west china. the remote and humid environment, traditional ways of life, contaminated potable water and limited health services all contribute to the transmission and persistence of fecal parasites.200318159450
[value of screening for intestinal and urinary parasites in non-resident permanent students in tunisia].in order to fight digestive and urinary parasitoses, a national program of surveillance has been founded. the screening of these parasitoses among the non permanent resident students in tunisia (enrpts) is one of the main actions of this program. among 2560 enrpts tested in the laboratory of parasitologie of institut pasteur of tunis, between 1998 and 2002, 674 were infected by parasites, which represents a global prévalence of 26.3%. the intestinal protozoa constitute the majority of parasites ...200315941065
distribution and differential diagnosis of entamoeba histolytica from entamoeba dispar by the pcr-rflp method in central iran.entamoeba histolytica and entamoeba dispar are two morphologically indistinguishable human protozoan parasites that are genetically distinct species. the potential invasive pathogenic entamoeba histolytica and non-invasive parasite entamoeba dispar can be differentiated by molecular and other methods. we used polymerase chain reaction (pcr) to determine the ratio of the two species in a population in tehran and karaj in central iran.200316868369
malaria and intestinal parasitosis among children presenting to the paediatric centre in sana'a, yemen.we studied the profile of malaria and intestinal parasitosis among children presenting to the paediatric health centre in sana'a from january 1998 to december 2000. in stool samples from 9014 children, ascaris lumbricoides, entamoeba histolytica, giardia lamblia and trichuris trichiura were the most common. infection with parasites of direct life-cycle were similar in boys and girls. schistosome infection was significantly higher in boys than girls, but girls were more infected with ascariasis. ...200316450536
first report of escherichia coli o157 among iraqi children.we determined the prevalence of enterohaemorrhagic escherichia coli, especially e. coli o157, and other enteropathogens among 200 children with bloody diarrhoea and 100 age-matched controls at two baghdad hospitals. bacterial and parasitic agents were found in 39.5% and 28.5% of cases, respectively; no pathogen was detected in 32%. e. coli o157 was identified in 11.5% and more than one pathogen was found in 15.5% of cases. the most common pathogens were enteropathogenic e. coli (epec) (5%); e. c ...200315562746
[treatment of acanthamoeba keratitis: possibilities, problems, and new approaches].acanthamoeba keratitis is a corneal disease associated predominantly with contact lens wear. the occurrence of acanthamoeba keratitis has been rising since 1990 in correlation to the growing number of contact lens wearers. to date approximately 2000 cases have been published around the world. due to the complicated diagnostics, the elaborate treatment and the usually bad compliance of the patients, acanthamoeba keratitis unfortunately very often takes a serious progression, which may lead to ser ...200315508774
purification of entamoeba histolytica dna containing organelles (ekhos): a further characterization. 200314736228
intestinal parasites among african refugees resettled in massachusetts and the impact of an overseas pre-departure treatment program.this study analyzed the prevalence of intestinal parasitoses diagnosed shortly after arrival in the united states among african refugees before and after implementation of an overseas program of empirical treatment with albendazole. variables included results of microscopy of a single stool specimen, age, sex, ethnicity, departure origin, and receipt of albendazole. of 1,254 refugees, 56% had intestinal parasites. fourteen percent had helminths, and 2% had multiple helminths. in addition, 52% ha ...200314740885
a virulence attenuated amoebapore-less mutant of entamoeba histolytica and its interaction with host cells.entamoeba histolytica, the protozoan parasite which causes amoebiasis, is an exclusively human pathogen so developing a vaccine could effectively impact the spread of the disease. recently we developed a genetically modified avirulent strain, termed g3, from the virulent e. histolytica strain hm-1:imss. the new strain lacks the important virulence factor, the amoebapore-a. the objective of our current study was to investigate the avirulence of the attenuated strain as well as to examine the anti ...200314636681
intestinal antilectin immunoglobulin a antibody response and immunity to entamoeba dispar infection following cure of amebic liver abscess.we followed 93 subjects with amebic liver abscess (ala) and 963 close associate controls at 3-month intervals for 36 months to characterize intestinal and humoral antibody responses to the amebic galactose-inhibitable lectin and to determine whether immunity developed to entamoeba histolytica or entamoeba dispar infection following cure of ala. we found that ala subjects had a higher prevalence and level of intestinal antilectin immunoglobulin a (iga) and serum anti-lc3 (cysteine-rich recombinan ...200314638778
epidemiologic and clinical characteristics of acute diarrhea with emphasis on entamoeba histolytica infections in preschool children in an urban slum of dhaka, bangladesh.the epidemiology, clinical features, nutritional status, and causative agents of diarrhea were studied in 289 bangladeshi children (147 boys and 142 girls) 2-5 years old. the use of improved diagnostic tests for amebiasis enabled for the first time analysis of the contribution of entamoeba histolytica to total diarrheal illness in this community setting. the average incidence rate of diarrhea was 1.8/child-year, and the average number of diarrheal days was 3.7 days/child-year over an average obs ...200314640500
bfa-sensitive and insensitive exocytic pathways in entamoeba histolytica trophozoites: their relationship to pathogenesis.entamoeba histolytica manifests its pathogenicity through several cellular processes triggered by external stimuli that activate signal transduction pathways. the intense secretory activity resulting from stimulation is not correlated with a typical endoplasmic reticulum (er) or golgi organization, and little is known in this parasite about endocytic/exocytic pathways. the interactions of trophozoites with fibronectin (fn) and cultured mammalian cells, which elicit secretory activities, were cho ...200314641177
short communication: prevalence of entamoeba histolytica and entamoeba dispar in northern ghana.since the redescription of the potentially invasive entamoeba histolytica, separating it from the morphologically identical non-invasive entamoeba dispar, there is a need for the reassessment of epidemiological data on amoebiasis. in this context we conducted a descriptive survey on the presence of e. histolytica and e. dispar in a rural area in northern ghana. we found a high prevalence (39.8%) of the e. histolytica/e. dispar complex with microscopy, but e. histolytica and e. dispar-specific dn ...200314641852
meeting report: embo workshop "pathogenesis of amoebiasis: from genomics to disease", institut pasteur, paris, may 19-22, 2003. 200314658490
evidence for golgi bodies in proposed 'golgi-lacking' lineages.golgi bodies are nearly ubiquitous in eukaryotic cells. the apparent lack of such structures in certain eukaryotic lineages might be taken to mean that these protists evolved prior to the acquisition of the golgi, and it raises questions of how these organisms function in the absence of this crucial organelle. here, we report gene sequences from five proposed 'golgi-lacking' organisms (giardia intestinalis, spironucleus barkhanus, entamoeba histolytica, naegleria gruberi and mastigamoeba balamut ...200314667372
an epidemiological study of pleuropulmonary paragonimiasis among pupils in the peri-urban zone of kumba town, meme division, cameroon.paragonimiasis have previously been reported in two zones of the southwest province of cameroon including the kupe mountain and mundani foci. the aim of this study was to investigate the presence and epidemiology of paragonimiasis in the peri-urban zone of kumba, meme division, located about 50 km away from the kupe mountain focus.200314678562
collagen-induced stat family members activation in entamoeba histolytica trophozoites.the interaction of entamoeba histolytica trophozoites with collagen type i and calcium induces a membrane to nuclei signaling. the transduction pathways involved in such phenomena are still poorly understood. using a combination of immunoprecipitation assays, western immunoblot analysis, electrophoretic mobility shift assays and immunocytochemistry we demonstrate here the expression, tyrosine phosphorylation, nuclear translocation and dna binding of two members of the signal transducers and acti ...200314680700
identification and characterization of a cyclooxygenase-like enzyme from entamoeba histolytica.the intestinal protozoan parasite entamoeba histolytica remains a significant cause of morbidity and mortality worldwide. however, almost nothing is known about the molecules secreted by the parasite that modulate host immune responses or epithelial barrier function in the colon. herein, we describe the isolation and characterization of a cyclooxygenase (cox)-like enzyme in e. histolytica that is responsible for the biosynthesis of prostaglandin (pg)e2. pge2 produced by ameba was constitutive bu ...200314585927
detection and identification of entamoeba species in stool samples by a reverse line hybridization assay.classically, detection of entamoeba histolytica is performed by microscopic examination for characteristic cysts and/or trophozoites in fecal preparations. differentiation of e. histolytica cysts and those of nonpathogenic amoebic species is made on the basis of the appearance and the size of the cysts. however, by classical means objective tools for confirmation and quality control do not exist. therefore, a reverse line blot hybridization assay was developed to detect a variety of entamoeba sp ...200314605136
mitochondrial remnant organelles of giardia function in iron-sulphur protein maturation.giardia intestinalis (syn. lamblia) is one of the most widespread intestinal protozoan pathogens worldwide, causing hundreds of thousands of cases of diarrhoea each year. giardia is a member of the diplomonads, often described as an ancient protist group whose primitive nature is suggested by the lack of typical eukaryotic organelles (for example, mitochondria, peroxisomes), the presence of a poorly developed endomembrane system and by their early branching in a number of gene phylogenies. the d ...200314614504
the cell cycle of entamoeba histolytica.entamoeba histolytica, is a microaerophilic protist, which causes amoebic dysentery in humans. this unicellular organism proliferates in the human intestine as the motile trophozoite and survives the hostile environment outside the human host as the dormant quadri-nucleate cyst. lack of organelles--such as mitochondria and golgi bodies--and an unequal mode of cell division, led to the popular belief, that this organism preceded other eukaryotes during evolution. however, data from several labora ...200314619972
intestinal parasites in children, in highly deprived areas in the border region of chiapas, mexico.to assess the prevalence of intestinal parasitic infections among children in highly deprived areas, and its possible association with demographic and socioeconomic indicators.200314628618
entamoeba histolytica: an update.over the past decade, since it was formally recognized that entamoeba histolytica and entamoeba dispar were two distinct species, studies in this field have made dramatic in-roads into the understanding of e. histolytica and the pathogenesis of invasive amoebiasis. over the same period it has also become clear that the true incidence of e. histolytica infection, particularly in vulnerable populations such as low socioeconomic children, is exceedingly high. understanding the epidemiology, pathoph ...200314502002
[nine-year progression of amoebal rectitis]. 200314506451
regulatory effects of il-12 and il-18 on onchocerca volvulus- and entamoeba histolytica-specific cellular reactivity and cytokine profiles.in the present study, the cytokines interleukin (il)-12 and il-18 were evaluated for their capacity to modulate and to re-direct in vitro parasite antigen-specific cellular responsiveness in patients exposed to onchocerca volvulus and entamoeba histolytica infection. we found that il-18 was highly capable of reducing parasite antigen-induced il-10 production by pbmc. in contrast, addition or neutralization of il-12, also in combination with il-18 and the interferon-gamma-inducible chemokine ip-1 ...200314507330
oral cavity as a potential source of infections in recipients with diabetes mellitus.our previous observations showed alterations of oral cavity status among hemodialyzed patients and kidney allograft recipients as well as differences in the prevalence and composition of microorganisms occurring in the mouths of patients. in the present work, we analysed the results of oral cavity examinations, the identification of microorganisms, and the assessment of their importance to kidney allograft recipients or hemodialyzed patients with diabetes mellitus, in comparison with nondiabetic ...200314529890
etiology of acute diarrhea in adults in southwestern nigeria.stool specimens from 113 adult outpatients with diarrhea in southwestern nigeria and 63 controls were examined for bacterial and parasitic enteric pathogens. enterohemorrhagic escherichia coli (ehec) (p < 0.02), enteroaggregative e. coli (eaec) (p < 0.02), and entamoeba histolytica (p < 0.0002) were significantly associated with diarrhea. salmonella, shigella, nontoxigenic vibrio cholerae, other categories of diarrheagenic e. coli, as well as a variety of helminths were recovered more frequently ...200314532177
longitudinal study of intestinal entamoeba histolytica infections in asymptomatic adult carriers.to gain insight into the dynamics of intestinal entamoeba histolytica infection, a longitudinal study was performed over an observation period of 15 months with a group of 383 randomly selected adult individuals (mean age, 38.5 years) living in an area of amebiasis endemicity in central vietnam. ameba infection was diagnosed by using species-specific pcr and dna extracted directly from fecal samples. the results indicated an e. histolytica prevalence of 11.2% and an annual new infection rate of ...200314532214
effective human defense against e. histolytica: high amoebicidal activity of lymphocytes and monocytes in amoebic liver abscess patients until 3 months follow-up.adherence of pathogenic entamoeba histolytica trophozoites mediated by gal/galnac lectin is a prerequisite for killing naïve t cells and monocytes but the activated t cells and monocyte derived macrophages (mdms) not only resist the attack but can kill the parasite. in the present study, we have analysed the adherence and cytotoxicity of the immunecompetent cells from patients of amoebic liver abscess at the time of their diagnosis and after 3 months to elucidate the development of cell mediated ...200314550474
nitric oxide synthase in entamoeba histolytica: its effect on rat aortic rings.nadph-diaphorase activity has been considered as a nitric oxide synthase (nos) marker. therefore, the presence of nadph-d activity in entamoeba histolytica suggests that they have nos activity. the aim of this work was to provide support for this contention. the amebic culture medium or amebic purified proteins induced relaxation of endothelium-denuded rat aortic rings pre-contracted with phenylephrine (10(-6) m), which was inhibited when the amebas were incubated with ng-monomethyl-l-arginine o ...200314552855
laboratory diagnosis of amebiasis.the detection of entamoeba histolytica, the causative agent of amebiasis, is an important goal of the clinical microbiology laboratory. to assess the scope of e. histolytica infection, it is necessary to utilize accurate diagnostic tools. as more is discovered about the molecular and cell biology of e. histolytica, there is great potential for further understanding the pathogenesis of amebiasis. molecular biology-based diagnosis may become the technique of choice in the future because establishm ...200314557296
glycogen phosphorylase sequences from the amitochondriate protists, trichomonas vaginalis, mastigamoeba balamuthi, entamoeba histolytica and giardia intestinalis.glycogen phosphorylase genes or messages from four amitochondriate eukaryotes, trichomonas vaginalis, mastigamoeba balamuthi, entamoeba histolytica (two genes) and giardia intestinalis, have been isolated and sequenced. the sequences of the amitochondriate protist enzymes appear to share a most recent common ancestor. the clade containing these sequences is closest to that of another protist, the slime mold (dictyostelium discoideum), and is more closely related to fungal and plant phosphorylase ...200314563176
intestinal parasitic infections in man: a review.intestinal parasites of importance to man are enterobius vermicularis, the soil-transmitted helminthes (sth)--ascaris lumbricoides tricburis trichiura, bookworms (necator americans/ancylostoma duodenale) and strongyloides stercoralis and the protozoa entamoeba histolytica and giardia duodenalis. other protozoa such as cryptosporidium sp. and isopora sp. are becoming important in causing prolonged diarrhea in immunocompromised patients. it is estimated that almost 1 billion, 500 million and 900 m ...200314569755
purification and biochemical characterization of a soluble alpha-glucosidase from the parasite entamoeba histolytica.a soluble alpha-glucosidase presumably involved in the general carbohydrate metabolism was purified from e. histolytica trophozoites by a three-step procedure consisting of ion exchange, size exclusion and adsorption chromatographies in columns of mono q, sepharose cl-6b and hydroxyapatite, respectively. after the last step, the enzyme was enriched about 673-fold over the starting material with a yield of 18%. sds-page revealed the presence in the purified preparations of two polypeptides of com ...200314574111
[prevalence of microsporidia and other intestinal parasites in patients with hiv infection, bogota, 2001].opportunistic intestinal parasites are a common cause of diarrhea in hiv-infected patients. to determine the prevalence of microsporidia and other opportunistic parasites infecting hiv patients in bogotá, colombia, 115 patients were examined for these infections during the year 2001. the institution and the sample percent from each are as follows: santa clara hospital, 33.0%; san pedro claver, 20.0%; simón bolívar hospital, 14.8%; san josé hospital, 13.9%; central de la policía hospital, 6.1%; c ...200314582330
using ancestral sequences to uncover potential gene homologues.gene homologues between distantly related species can be difficult to identify. we test the idea that inferred ancestral sequences could aid in finding gene homologues. ancestral sequences are inferred by aligning gene homologues on a known tree and estimating the most likely amino acid for each position at each node in that tree. blast(r) and hmmer are used separately and together with ancestral sequences to search the genome sequence databases of encephalitozoon cuniculi, entamoeba histolytica ...200315130821
consumption of l-arginine mediated by entamoeba histolytica l-arginase (eharg) inhibits amoebicidal activity and nitric oxide production by activated macrophages.in this study we discuss the cloning and expression of entamoeba histolytica arginase (eharg), an enzyme that catalyses the hydrolysis of l-arginine to l-ornithine and urea. l-norvaline, a competitive inhibitor of e. histolytica l-arginase, inhibits the growth of the parasite, which suggests that the catabolism of l-arginine mediated by eharg is essential. nitric oxide (no) is an antimicrobial agent that inhibits some key enzymes in the metabolism of entamoeba histolytica. no is synthesized by a ...200315053781
foodborne and waterborne parasites.more than 72 species of protozoan and helminth parasites can reach humans by food and water, and most of these infections are zoonoses. some parasites show a cosmopolitan distribution, others a more restricted distribution due to their complex life cycles, which need the presence of one or more intermediate hosts. of this large number of pathogens, only toxoplasma gondii can be transmitted to humans by two different ways, i.e., by cysts present in infected meat and by oocysts contaminating food ...200315058817
environmental contamination with protozoan parasite infective stages: biology and risk assessment.in the present paper some aspects of the biology and various factors influencing the potential for environmental contamination with protozoan parasites infective stages implicated in water and foodborne diseases are described. the major protozoan species that affect humans are entamoeba histolytica, acanthamoeba sp., neagleria sp. giardia intestinalis, cryptosporidium parvum, cyclospora cayetanensis, toxoplasma gondii, isospora/sarcocystis sp. encephalitozoom intestinals and enterocytozoon biene ...200315058818
[a diagnostic approach to hepatic abscess].the non invasive diagnosis of amebic liver abscess allows the use of empirical therapy without the requirement of invasive diagnostic procedures.200315022404
[parasitic diarrhea in children].in many areas, entamoeba histolytica and entamoeba dispar are found together and their microscopic appearance is identical. biochemical tests which can show cell wall differences are often falsely negative and the only possible way is to treat with metronidazole when amoebiasis is suspected. in case of clinical failure of metronidazole, a bacterial diarrhea is frequently found. giardia is an other protozoa frequently found in stools of children in endemic areas. diarrheas due to giardia are poss ...200315022781
bifunctional aldehyde/alcohol dehydrogenase (adhe) in chlorophyte algal mitochondria.protein profiles of mitochondria isolated from the heterotrophic chlorophyte polytomella sp. grown on ethanol at ph 6.0 and ph 3.7 were analyzed by blue native and denaturing polyacrylamide gel electrophoresis. steady-state levels of oxidative phosphorylation complexes were influenced by external ph. levels of an abundant, soluble, mitochondrial protein of 85 kda and its corresponding mrna increased at ph 6.0 relative to ph 3.7. n-terminal and internal sequencing of the 85 kda mitochondrial prot ...200314756315
evaluation of newer diagnostic methods for the detection and differentiation of entamoeba histolytica in an endemic area.we evaluated the colorimetric polymerase chain reaction (pcr)-based method for the detection and differentiation of entamoeba spp. and compared the efficacy of e. histolytica-specific antigen detection in faeces with the detection of specific antibodies to e. histolytica-specific antigen in faeces, by enzyme-linked immunosorbent assay. faecal samples were obtained from patients attending hospital in chandigarh, india, from march 2001 to february 2002. the pcr-based colorimetric method was found ...200315259465
an anti-inflammatory oligopeptide produced by entamoeba histolytica down-regulates the expression of pro-inflammatory chemokines.axenically grown entamoeba histolytica produces a pentapeptide (met-gln-cys-asn-ser) with anti-inflammatory properties that, among others, inhibits the in vitro and in vivo locomotion of human monocytes, sparing polymorphonuclear leucocytes from this effect [hence the name originally given. monocyte locomotion inhibitory factor (mlif)]. a synthetic construct of this peptide displays the same effects as the native material. we now added mlif to resting and pma-stimulated cells of a human monocyte ...200315157024
human amoebic hepatic abscess: in situ interactions between trophozoites, macrophages, neutrophils and t cells.amoebic liver abscesses (ala) are the most frequent and severe extraintestinal clinical presentations of amoebiasis. during the early establishment of amoebae in the liver parenchyma, as well as during the extension of the tissue necrosis, parasites interact with the parenchymal liver cells and, as a consequence of these interactions, hepatocytes can be destroyed and host immune cells can become activated. however, little is known about the nature of these interactions in the liver or about the ...200315157027
overdiagnosis of amoebiasis in the absence of entamoeba histolytica among patients presenting with diarrhoea in wonji and akaki, ethiopia.to confirm the high reported incidence of intestinal amoebiasis among study participants at 2 cohort sites in ethiopia where an hiv/aids study is taking place, stool samples of 232 patients with complaints of diarrhoea were examined for the presence of entamoeba histolytica and e. dispar dna between april and december 2001. by microscopy, 91 (39%) of the study participants were reported to harbour entamoeba trophozoites and/or four-nucleated cysts. using specific e. histolytica and e. dispar dna ...200315228248
ehpak, a member of the p21-activated kinase family, is involved in the control of entamoeba histolytica migration and phagocytosis.entamoeba histolytica migration is essential for the development of amoebiasis, a human disease characterised by invasion and destruction of tissues. amoebic motility requires both polarisation of the cell and formation of a predominant pseudopod. as p21-activated kinases paks are known to regulate eukaryotic cell motility and morphology, we investigated the role of pak in e. histolytica. we showed that the c-terminal domain of ehpak comprised a constitutive kinase activity in vitro and that ove ...200312456716
calcium modulates promoter occupancy by the entamoeba histolytica ca2+-binding transcription factor ure3-bp.the entamoeba histolytica upstream regulatory element 3-binding protein (ure3-bp) binds to the ure3 sequence of the gal/galnac-inhibitable lectin hgl5 and ferredoxin 1 (fdx) gene promoters. this binding can be inhibited in vitro by addition of calcium. two ef-hand motifs, which are associated with the ability to bind calcium, are present in the amino acid sequence of ure3-bp. mutation of the second ef-hand motif in ure3-bp resulted in the loss of calcium inhibition of dna binding as monitored by ...200312466263
nitric oxide inhibits cysteine proteinases and alcohol dehydrogenase 2 of entamoeba histolytica.nitric oxide is involved in the neutrophil and macrophage killing of the protozoan parasite entamoeba histolytica. in the present study, we found that cysteine proteinases, significant contributors to amebic virulence and alcohol dehydrogenase 2, an enzyme absolutely required for the survival of the parasite, are both significantly inhibited by s-nitroso-glutathione, a physiological nitric oxide donor, within the concentration range 0.5-2.0 m m.200312489015
detection and differentiation of entamoeba histolytica and entamoeba dispar isolates in clinical samples by pcr and enzyme-linked immunosorbent assay.differential diagnosis of entamoeba histolytica (pathogenic) and entamoeba dispar (nonpathogenic), which are two morphologically identical species of amebae, is essential both for treatment decision and public health knowledge. the study reported here was designed to choose a reference differentiation technique. stool samples (n = 95) were tested by microscopy, techlab enzyme-linked immunosorbent assays (elisas), and an in-house pcr. the target for the pcr amplification was a small region (135 b ...200312517854
cytogenetic evaluation of two nitroimidazole derivatives.5-nitroimidazoles are a well-established group of antiprotozoal and antibacterial agents. thanks to their antimicrobial activity these chemotherapeutic agents inhibit the growth of both anaerobic bacteria and certain anaerobic protozoa such as trichomonas vaginalis, entamoeba histolytica and giardia lamblia. the aim of the present study is to achieve a precise characterization of the genotoxic activity of these compounds and to establish the value of cytogenetic assays in order to determine the ...200312537960
entamoeba histolytica cysteine proteinases disrupt the polymeric structure of colonic mucin and alter its protective function.the adherent mucous gel layer lining the colonic epithelium is the first line of host defense against invasive pathogens, such as entamoeba histolytica. the mucous layer prevents the attachment of amoeba to the colonic epithelium by trapping and aiding in the expulsion of the parasite. disruption of the mucous layer is thought to occur in invasive amebiasis, and the mechanism by which the parasite overcomes this barrier is not known. the aim of this study was to characterize the specific interac ...200312540564
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