| effect of zinc on entamoeba histolytica pathogenicity. | the present study analyzes the effects of zinc on entamoeba histolytica activity and on its pathogenicity. metal activity was evaluated in vitro with regard to the parasite's viability, replication, and adhesion to epithelial cells and in vivo with regard to its pathogenicity. the results obtained in vitro show that zinc at 1.0 mm concentration does not affect amebic viability; however, it does decrease amebic replication and adhesion (p < 0.001). in vivo studies performed on a model of experime ... | 1999 | 10344543 |
| detection of entamoeba dispar dna in macaque feces by polymerase chain reaction. | we used the polymerase chain reaction (pcr) to determine the prevalence of entamoeba histolytica and e. dispar in the wild population of macaque monkeys (macaca fuscata) in mt. takasaki, oita prefecture, japan. of the 101 samples collected, 41 (42.57%) were found to be positive for e. dispar. however, no e. histolytica was detected from the collected samples. the results of this survey demonstrate the high prevalence of e. dispar in macaque monkeys in the study area. moreover, they provide addit ... | 1999 | 10344544 |
| intestinal mucins in colonization and host defense against pathogens. | intestinal mucins are key components of the first line of host defense against intestinal pathogens. these large glycoconjugates secreted by specialized exocrine goblet cells form viscous gels that trap microorganisms and irritants and limit their diffusion to the intestinal epithelium. moreover, they allow for colonization by indigenous bacterial flora that prevents attachment of pathogenic microbes. the interaction between microbes and mucins involves mucin carbohydrate side chains and microbi ... | 1999 | 10344672 |
| geranins a and b, new antiprotozoal a-type proanthocyanidins from geranium niveum. | bioassay-guided fractionation of the antiprotozoal extract of geranium niveum led to the isolation of two new a-type proanthocyanidins, epi-afzelechin-(4beta-->8, 2beta-->o-->7)-afzelechin (1) and epi-catechin-(4beta-->8, 2beta-->o-->7)-afzelechin (2). compounds 1 and 2 were given the trivial names of geranins a and b, respectively. in addition, five known compounds, mahuannin b (3), reynoutrin (4), hyperin (5), methyl gallate (6), and 3-beta-caffeoyl-12-oleanen-28-oic acid (7), were obtained. t ... | 1999 | 10346950 |
| us and ct findings of rectal amebian abscess. | an interesting case of rectal amebic abscess is presented. ultrasound and ct images provided the diagnosis of a cystic intramural mass at the rectal wall of a young man, who complained of pelvic pain, constipation, and fever. his clinical history of amebiasis and the finding of trophozoids and cysts at the stool swap confirmed the diagnosis. intravenous metronidazole therapy cured the disease and led to total disappearance of the mass, and clinical well-being. | 1999 | 10354892 |
| amoebiasis among institutionalized psychiatric patients in taiwan. | although information on amoebiasis among institutionalized psychiatric patients is available, reports on the relationship between behaviour and this infection are not abundant. from july 1995 to june 1996, stool and blood samples were collected from 565 patients in three psychiatric hospitals of north taiwan. stool samples were examined using the direct smear and formalin-ethyl acetate sedimentation techniques as well as prospect entamoeba histolytica microplate assay kit. blood samples were exa ... | 1999 | 10355798 |
| significance of cryptosporidium in acute diarrhoea in north-eastern india. | in a hospital-based study, stool samples from 2095 patients of all ages were examined for different fungal, protozoal and bacterial enteropathogens over a period of 2 years (july 1994-june 1996). cryptosporidium was detected in 151 specimens (7.2%) and was the third commonest pathogen found. the highest prevalence of this organism was in the group aged 16-45 years and during the rainy months (july-oct.). diarrhoea caused by the protozoon was of mild to moderate severity and features of dysentery ... | 1999 | 10359300 |
| the mitosome, a novel organelle related to mitochondria in the amitochondrial parasite entamoeba histolytica. | ultrastructural analysis of entamoeba histolytica reveals that this intestinal human pathogen lacks recognizable mitochondria, but the presence in its genome of genes encoding proteins of mitochondrial origin suggests the existence of a mitochondrially derived compartment. we have cloned the full-length e. histolytica gene encoding one such protein, chaperonin cpn60, and have characterized its structure and expression. using an affinity-purified antibody raised against recombinant protein, we ha ... | 1999 | 10361303 |
| a model of multivalent ligand-receptor equilibria which explains the effect of multivalent binding inhibitors. | quantitative relationships based on multivalent ligand receptor binding equilibria are developed which can describe the enhanced binding observed when polyvalent ligands are used as inhibitors of cell/cell interactions. this theory is able to explain the many orders of magnitude difference reported between the apparent dissociation constants determined for the interaction of entamoeba histolytica membrane receptors with mono and multivalent n-acetylgalactosaminide inhibitors. given two experimen ... | 1999 | 10369416 |
| specific and reversible inhibition of entamoeba histolytica cysteine-proteinase activities by zn2+: implications for adhesion and cell damage. | cysteine-proteinases are thought to play an important role in e. histolytica pathogenicity. although effective blockage of proteolytic activities can be obtained with several known inhibitors, the high cellular toxicity of most of the inhibitors precludes experimentation with live cells or animal models. specific cysteine-proteinase inhibitors that could be utilized in studies of virulence are of great need in the field of amebiasis. | 1999 | 10372439 |
| cloning and sequencing of an acetyl-coa synthetase (adp-forming) gene from the amitochondriate protist, giardia lamblia. | a giardia lamblia gene, glacs, was cloned, sequenced and expressed in escheria coli. this gene codes for a 726 residue long acetyl-coa synthetase (adp-forming). this enzyme is responsible for the formation of acetate, a metabolic endproduct of g. lamblia. it is known from only two type i amitochondriate eukaryotes, g. lamblia and entamoeba histolytica and from the archaebacterium, pyrococcus furiosus. with glacs as query, homologous unidentified open reading frames were detected in the complete ... | 1999 | 10375639 |
| sequence-specific 1h, 13c and 15n assignments of a calcium binding protein from entamoeba histolytica. | | 1999 | 10382313 |
| dna polymerase activity in encysting entamoeba invadens. | using an axenic encystation system of entamoeba invadens as a model for e. histolytica encystation, we examined the level of dna polymerase activity in e. invadens during encystation induced in vitro. we first characterized the dna polymerase activity of trophozoites of e. invadens, comparing it with that of e. histolytica, and found that the activity of e. invadens was lower than that of e. histolytica at ph 2, 4, and 6 and was higher at ph 8 and 10. the activity of e. invadens was completely i ... | 1999 | 10382613 |
| molecular cloning of a cdna encoding 14-3-3 protein from the protozoan tetrahymena pyriformis and its mrna expression during synchronous division. | the 14-3-3 proteins have been identified in a wide variety of eukaryotic cells and diverse biochemical properties have been ascribed to them. here we have cloned a cdna encoding 14-3-3 protein from a cdna library of tetrahymena pyriformis. this cdna (tp14-3-3) encoded an open reading frame consisting of 244 amino acids with predicated molecular mass as 28.1kda. the predicted protein shares 59.2%, 56.5% and 59.2% identity to entamoeba histolytica 14-3-3-1, schizosaccharomyces pombe rad 24 and hum ... | 1999 | 10395893 |
| vaccine potential of 56-66 kda protease secreted by entamoeba histolytica. | excretory/secretory (es) antigens and sub-cellular fractions of e. histolytica (hm1:imss strain) were tested for the presence of common proteases using substrate gel electrophoresis. we obtained two e. histolytica proteases (56-66 kda and 29 kda) from es material, soluble components and plasma membrane. protease 56-66 kda from es antigen was selected for immunizing hamsters because it gave a consistent broad band. we observed 62.5 per cent protection in immunized animals, compared to 0 per cent ... | 1999 | 10402761 |
| prevalence and immune response to entamoeba histolytica infection in preschool children in bangladesh. | entamoeba histolytica infection was present in 5% and e. dispar in 13% of asymptomatic 2-5-year-old children from an urban slum of dhaka, bangladesh. entamoeba dispar-infected children were no more likely than uninfected children to have serum antibodies to lectin. in contrast, all children infected with e. histolytica had serum antibodies to lectin. this anti-lectin response included antibodies against the carbohydrate recognition domain, which have been demonstrated in animal models to confer ... | 1999 | 10403338 |
| entamoeba dispar contains but does not secrete acid phosphatase as does entamoeba histolytica. | | 1999 | 10403764 |
| a monoclonal antibody-based test system for detection of entamoeba histolytica-specific coproantigen. | diagnosis of amebiasis based on stool microscopy or demonstration of anti-amebic antibodies has limitations. a diagnostic system based on demonstration of the parasite product in clinical specimens holds promise. | 1999 | 10407562 |
| hbsag carrier with simultaneous amebic liver abscess and acute hepatitis e. | hepatitis e virus (hev) infection and amebiasis are waterborne diseases that are endemic in india. however, their co-occurrence has never been described. we report a patient who presented with fever, jaundice and tender hepatomegaly and on investigation was found to have coexisting acute hepatitis e and amebic liver abscess. incidentally, he was also an hbsag carrier. | 1999 | 10407569 |
| [amebic liver abscesses with bacterial superinfection in a nonendemic area]. | a 26-year-old man was admitted to hospital with asthenia, weight loss, right upper quadrant abdominal pain, diarrhea without blood, and fever. abdominal ultrasonography showed multiple hypoechoic areas in the left hepatic lobe. on abdominal ct, multiple hypodense areas without contrast capture were consistent with hepatic abscesses. cultures were obtained and the patient was placed empirically on metronidazole, gentamicin and ampicillin, without improvement in the first 72 hours, and a drain was ... | 1999 | 10410449 |
| antisense inhibition of expression of the light subunit (35 kda) of the gal/galnac lectin complex inhibits entamoeba histolytica virulence. | one of the under-represented genes identified by cdna representational difference analysis (rda) between avirulent entamoeba histolytica strain rahman and virulent strain hm-1:imss was the amoebic light (35 kda) subunit of the gal/galnac lectin complex. this lectin complex, which mediates the adhesion of the parasite to the target cell, also contains a heavy (170 kda) subunit, which has the carbohydrate-binding domain. stable transfectants of the virulent strain in which the expression of the 35 ... | 1999 | 10411749 |
| the cysteine-rich region of the entamoeba histolytica adherence lectin (170-kilodalton subunit) is sufficient for high-affinity gal/galnac-specific binding in vitro. | adherence of entamoeba histolytica trophozoites to colonic mucin, epithelium, and other target cells is mediated by the amebic gal/galnac lectin. we constructed in vitro expression vectors containing full-length (residues 1 to 1280), cysteine-poor (1 to 353 and 1 to 480), and cysteine-rich (356 to 1143 and 480 to 900) fragments of the gene encoding the heavy subunit of the adherence lectin, hgl2. in vitro transcription followed by translation using a nuclease-treated rabbit reticulocyte lysate s ... | 1999 | 10417146 |
| entamoeba histolytica : a novel cysteine protease and an adhesin form the 112 kda surface protein. | here, we present evidence that a cysteine protease (ehcp112) and a protein with an adherence domain (ehadh112) form the entamoeba histolytica 112 kda adhesin. immunoelectron microscopy and immunofluorescence assays using monoclonal antibodies (mabadh) revealed that, during phagocytosis, the adhesin is translocated from the plasma membrane to phagocytic vacuoles. mabadh inhibited 54% adherence, 41% phagocytosis, and 35% and 62% destruction of mdck cell monolayers by live trophozoites and their ex ... | 1999 | 10417646 |
| antimicrobial and cytolytic polypeptides of amoeboid protozoa--effector molecules of primitive phagocytes. | amoebae are primitive, actively phagocytosing eukaryotic cells, many of which use bacteria as a major nutrient source. one may suppose that amoebae possess an array of potent antimicrobial molecules acting in synergy to combat bacterial growth inside their phagosomes. lysosome-like granular vesicles of entamoeba histolytica contain a family of 77-residue peptides with a compact alpha-helical, disulfide-bonded fold. these polypeptides, named amoebapores, exhibit antibacterial and cytolytic activi ... | 1999 | 10426421 |
| dna sequences corresponding to the ariel gene family of entamoeba histolytica are not present in e. dispar. | for the identification of quantitative genetic differences between pathogenic entamoeba histolytica and the closely related but nonpathogenic species e. dispar, a set of 68 independent probes that had previously been isolated from an e. histolytica cdna library were hybridized to total genomic dna of both amoeba species. besides ehcp5, the sequence that codes for cysteine proteinase 5 and has recently been shown to be missing in e. dispar, only one of the probes exclusively reacted with e. histo ... | 1999 | 10431751 |
| [invasive amebiasis at an institution for the mentally retarded in hyogo prefecture]. | an outbreak of amebiasis caused by entamoeba histolytica occurred at an institution for mentally retarded persons in hyogo prefecture. twelve out of a total of 49 admitted persons exhibited e. histolytica cysts in their stool, and 13 including persons in whom no cysts had been detected showed positive serological reactions for e. histolytica infection. however, neither the cyst nor the antibody against the organism was detected in the staff members of the institution. indirect fluorescence antib ... | 1999 | 10442047 |
| asymptomatic amebic colitis in a homosexual man. | we describe case of a 75-yr-old japanese homosexual man who was diagnosed as having amebic colitis. the present case is unique in that invasive amebiasis has occurred in a homosexual man, because entamoeba histolytica in homosexual patients is considered to be a nonpathogenic and commensal organism in western countries, and that the patient has not complained of any gastrointestinal symptoms associated with minute colonic lesion of an isolated cecal ulcer. this report indicates that the absence ... | 1999 | 10445573 |
| immunochromatographic strip-based detection of entamoeba histolytica-e. dispar and giardia lamblia coproantigen. | biosite triage was 68.3% sensitive and 100% specific for the detection of entamoeba histolytica-e. dispar (n = 71) compared to alexon-trend's prospect test (reference standard) using fresh-frozen stool. neither test is able to distinguish e. histolytica from e. dispar. triage was 83.3% sensitive and 100% specific compared to microscopy (formalin-ether concentrates and permanent stains) for the detection of giardia lamblia. | 1999 | 10449494 |
| analysis by enzyme-linked immunosorbent assay and pcr of human liver abscess aspirates from patients in china for entamoeba histolytica. | aspirates of liver abscesses were analyzed for entamoeba histolytica. pcr detected a gene encoding a 30-kda protein in all samples but detected the ribosomal dna gene in only 14 (33.3%) samples. enzyme-linked immunosorbent assay detected antigen in 41 (97.6%) samples. pcr analysis of a strain-specific antigen (ssg) revealed that abscesses were caused by various strains. | 1999 | 10449500 |
| intestinal amoebiasis, giardiasis and geohelminthiases: their association with other intestinal parasites and reported intestinal symptoms. | in order to determine reported signs and symptoms that may predict an intestinal parasitic infection, 241 schoolchildren in western côte d'ivoire were interviewed with a simple questionnaire and their stool specimens were examined over several consecutive days. special emphasis was placed on (i) assessing infections by entamoeba histolytica/e. dispar, giardia duodenalis and by intestinal worms, (ii) looking for associations between these parasites, and (iii) looking for associations between thes ... | 1999 | 10450435 |
| virulence factors of entamoeba histolytica. | recent studies have increased our knowledge of entamoeba histolytica cell biology and gene regulation. in the ameba, dominant-negative mutations in the gal/galnac lectin affect adhesion and cytolysis, whereas mutations in meromyosin affect cytoskeletal function. studying these mutant proteins has improved our understanding of the role of these proteins in e. histolytica virulence. the characterization of the cp5 cysteine protease and the induction of apoptosis in host target cells has led to a b ... | 1999 | 10458982 |
| common presentations of amebic liver abscess. | the most common extraintestinal manifestation of entamoeba histolytica, the agent of amebiasis, is a hepatic abscess. this infection is common throughout the world and can be associated with life-threatening consequences. given the often nonspecific nature of the complaints related to an amebic abscess, a retrospective review of patients with confirmed disease was done to recognize the most common patterns of presentation. | 1999 | 10459092 |
| gtpases in protozoan parasites: tools for cell biology and chemotherapy. | small g proteins belong to a superfamily of gtpases related to the protooncogene ras, and function as master control elements for a range of cellular functions. this ability is related to their low rate of substrate turnover; gtpases catalyse the conversion of gtp to gdp, but with a rate in the order of one substrate per second, orders of magnitude slower than 'good' enzyme catalysis, but placing the reaction into the temporal frame of many cellular processes including signal transduction, cytos ... | 1999 | 10461165 |
| keto-acid oxidoreductases in the anaerobic protozoa. | in anaerobes, decarboxylation of pyruvate is executed by the enzyme pyruvate:ferredoxin oxidoreductase, which donates electrons to ferredoxin. the pyruvate:ferredoxin oxidoreductase and its homologues utilise many alternative substrates in bacterial anaerobes. the pyruvate:ferredoxin oxidoreductase from anaerobic protozoa, such as giardia duodenalis, trichomonas vaginalis, and entamoeba histolytica have retained this diversity in usage of alternative keto acids for energy production utilising a ... | 1999 | 10461388 |
| case studies in international travelers. | family physicians should be alert for unusual diseases in patients who are returning from foreign travel. malaria is a potentially fatal disease that can be acquired by travelers to certain areas of the world, primarily developing nations. transmitted through the bite of the anopheles mosquito, malaria usually presents with fever and a vague systemic illness. the disease is diagnosed by demonstration of plasmodium organisms on a specially prepared blood film. travelers can also acquire amebic in ... | 1999 | 10465222 |
| co-agglutination test for the detection of circulating antigen in amebic liver abscess. | we report here a simple and economical slide agglutination test, the co-agglutination (co-a) test, for the detection of circulating amebic antigen in sera for the diagnosis of amebic liver abscess. fifty serum specimens from cases of amebic liver abscess, 25 from other individuals with parasitic and miscellaneous infections, and 25 from healthy controls were tested for the presence of serum antigen by the co-a test. forty-five (90%) amebic liver abscess sera were found to be amebic-antigen posit ... | 1999 | 10466984 |
| detection by hplc of a trypanothione synthetase activity in vitro from entamoeba histolytica. | we have previously demonstrated the presence of glutathione-spermidine (gsp) and trypanothione [t(sh)(2)] from entamoeba histolytica trophozoites, on the basis of results obtained with acid extracts purified by florisil and deae-cellulose, derivatized with the fluorescent reagent monobromobimane and separated by hplc. gsp was originally found in escherichia coli and later in trypanosomatids such as trypanosoma cruzi, t. brucei, t. congolense and the insect trypanosomatid crithidia fasciculata, a ... | 1999 | 10467117 |
| entamoeba histolytica: a eukaryote with trypanothione metabolism instead of glutathione metabolism. | entamoeba histolytica is a human pathogen that lacks the capacity to synthesize glutathione but can incorporate it, from the growth media or presumably from the human host, to form trypanothione [n(1), n(8)-bis(glutathionyl)-spermidine conjugate]. this novel thiol compound has previously been found in trypanosomatids, as has its precursor glutathionyl-spermidine, which was originally detected in escherichia coli. previously we showed the presence of these two thiol compounds in extracts from cul ... | 1999 | 10467118 |
| metronidazole resistance in the protozoan parasite entamoeba histolytica is associated with increased expression of iron-containing superoxide dismutase and peroxiredoxin and decreased expression of ferredoxin 1 and flavin reductase. | to obtain insight into the mechanism of metronidazole resistance in the protozoan parasite entamoeba histolytica, amoeba trophozoites were selected in vitro by stepwise exposures to increasing amounts of metronidazole, starting with sublethal doses of 4 microm. subsequently, amoebae made resistant were able to continuously multiply in the presence of a 40 microm concentration of the drug. in contrast to mechanisms of metronidazole resistance in other protozoan parasites, resistant amoebae did no ... | 1999 | 10473552 |
| sesquiterpene lactones from neurolaena oaxacana | twelve sesquiterpene lactones, two new (1 and 2) and 10 known neurolenin-type germacranolides and furanoheliangolides (3-12) were isolated from neurolaena oaxacana, and their structures were elucidated by nmr and gc-ms analysis. the chemotaxonomic importance of these findings is discussed. as n. lobata is used against dysenteries, neurolenin b (4) and a mixture of the neurolenins c (5) and d (6) were tested against entamoeba histolytica and giardia intestinalis. | 1999 | 10479310 |
| [prevalence of intestinal parasitic infections in nursery schools from ciego de avila province, cuba. 1989-1993]. | the prevalence of intestinal parasitsm in nursery schools from ciego de avila province was annually avaluated during 1989-1993. the percentage of infected children ranged from 16.6% to 31.6%. an increase of frequence of infection was observed from 1991. protozoa were more predominant than helminths. in the whole five-year period studied giardia intestinalis had a higher prevalence (19.6%) followed by entamoeba histolytica (3.0%). the nematode most frequently found was trichuris trichiura (0.5%). | 1999 | 10488590 |
| [seasonal variation of intestinal protozoa infections in outpatients of the north section of santiago, chile. 1995-1996]. | formalin preserved fecal samples from 6,058 and 5,863 outpatients were examined for intestinal parasites during 1995 and 1996 respectively. prevalence rates of infections by intestinal protozoa in both years were similar. by age group (0-9, 10-19 and > 20 years old) blastocystis hominis was observed in 18.6-19.3, 37.0-31.1 and 25.3-25.4% in 1995-1996 respectively. prevalence of giardia intestinalis infections decreased from 16.6-17.4% in the 0-9 year-old children group to 4.1-4.5% in patients ov ... | 1999 | 10488591 |
| the effect of formalin fixation on the polymerase chain reaction characterization of entamoeba histolytica. | formalin fixation is the most common storage, transportation and preservation method for stool samples. however, fixation dramatically reduces our ability to extract from stool samples dna that is a suitable template for polymerase chain reaction (pcr)-based diagnostic tests. in this study we evaluated the effects of formalin concentration and of the time stored in fixative on the success of pcr amplification. we found that the deleterious effects of formalin are both time and concentration depe ... | 1999 | 10492774 |
| hla characterization in adult asymptomatic cyst passers of entamoeba histolytica/e. dispar. | the present work aimed at studying the possible association of hla antigens with entamoeba histolytica/e. dispar asymptomatic infection in a mexican mestizo population. a case-control design was selected for evaluation of the role of genetic markers in parasite infection. for this purpose the hla-a, hla-b, and hla-dr profiles of a population of asymptomatic e. histolytica/e. dispar adult cyst passers (cases) and a corresponding nonparasitized adult group (controls) followed for 12 months were id ... | 1999 | 10494810 |
| comparative modeling of amoebapores and granulysin based on the nk-lysin structure-structural and functional implications. | amoebapores, the pore-forming polypeptides of the protozoan parasite entamoeba histolytica, and effector proteins of porcine and human lymphocytes, namely nk-lysin and granulysin, reveal a substantial sequence similarity despite their enormous evolutionary distance. moreover, all these polypeptides display antibacterial activity and are in higher concentrations cytolytic to eukaryotic cells. the recently solved nmr structure of nk-lysin enabled us to build the three dimensional structures of amo ... | 1999 | 10494853 |
| growth stimulation by serum in entamoeba histolytica is associated with protein tyrosine dephosphorylation. | very little protein tyrosine phosphorylation was observed in growing (exponential-phase) entamoeba histolytica cells by immunoblotting and quantitative immunofluorescence. after 1 h of serum deprivation, two proteins (42 and 38 kda in sds-page) were tyrosine phosphorylated and two more proteins (96 and 63 kda) also showed tyrosine phosphorylation when examined after 4 h of serum deprivation. intense enhancements of anti-phosphotyrosine immunofluorescence levels were observed during this period o ... | 1999 | 10499274 |
| [cross-sectional study of intestinal parasites and chagas' disease in the municipality of novo airão, state of amazonas, brazil]. | a cross-sectional study was performed on the residents of one in every ten households in the town of novo airão, in the northern meso-region of the state of amazonas, 250 kilometers from manaus by riverboat. a family cluster sample of 89 dwellings was studied. a stool sample was requested from each of the inhabitants for examination using the lutz sedimentation and baermann-moraes-coutinho techniques, and blood was taken by venous puncture for trypanosoma cruzi elisa antibody testing and immunof ... | 1999 | 10502145 |
| in vivo nanoimaging and ultrastructure of entamoeba histolytica by using atomic force microscopy. | | 1999 | 10502472 |
| entamoeba histolytica: identification and properties of membrane-bound and soluble alpha-glucosidases. | | 1999 | 10502475 |
| mucoid presentation of acute enterocolitis in children: a hospital-based case-control study. | a hospital-based case-control study was carried out to clarify the characteristics of mucoid presentation of acute enterocolitis in children. one hundred sixty-eight cases of acute mucoid enterocolitis (study population) were compared with 200 cases of watery diarrhoea and 118 cases of blood dysentery (control groups) on the basis of clinical characteristics and findings on stool examination. study and control groups were comparable with respect to age, body weight and nutritional status. there ... | 1999 | 10503679 |
| entamoeba histolytica outbreaks in institutions for the mentally retarded. | | 1999 | 10508000 |
| secondary structure of a calcium binding protein (cabp) from entamoeba histolytica. | a calcium binding protein from entamoeba histolytica, (ehcabp, m(r) approximately 15 kda) is the causative agent for amoebiosis and has a very low sequence homology (approximately 30%) with other known cabps. almost complete sequence specific resonance assignments for (1)h, (13)c and (15)n spins in ehcabp were obtained using double and triple resonance nmr experiments. qualitative interpretation of the nuclear overhauser enhancements, chemical shift indices and of hydrogen exchange rates threw v ... | 1999 | 10508916 |
| entamoeba histolytica lacks trypanothione metabolism. | entamoeba histolytica lacks glutathione reductase activity and the ability to synthesise glutathione de novo. however, a recent report suggested that exogenous glutathione can be taken up and conjugated to spermidine to form trypanothione, a metabolite found so far only in trypanosomatids. given the therapeutic implications of this observation, we have carefully analysed e. histolytica for evidence of trypanothione metabolism. using a sensitive fluorescence-based hplc detection system we could c ... | 1999 | 10514081 |
| trendys in biochemistry-98. | | 1998 | 10515725 |
| pore-forming peptides of entamoeba dispar. similarity and divergence to amoebapores in structure, expression and activity. | amoebapore, a 77-residue peptide with pore-forming activity from the human pathogen entamoeba histolytica, is implicated in the killing of phagocytosed bacteria and in the cytolytic reaction of the amoeba against host cells. previously, we structurally and functionally characterized three amoebapore isoforms in e. histolytica but recognized only one homolog in the closely related but non-pathogenic species entamoeba dispar. here, we identified two novel amoebapore homologs from e. dispar by mole ... | 1999 | 10518795 |
| expression of in vitro virulence by entamoeba histolytica: effect of calmodulin inhibitors. | the possible role of calmodulin (cam) in functions such as cytotoxicity, phagocytosis, and amoebic growth was studied. these are important factors for the in vitro pathogenicity of entamoeba histolytica hm1 strain. the cam inhibitors trifluoperazine (tfp), n-(6-aminohexyl)-5-chloro-1-naphthalene-sulfonamide (w-7) and n-(6-aminohexyl)-naphthalenesulfonamide (w-5) were used for these purposes. cytotoxicity was determined as the ability of amoebae to kill and/or lyse nucleated mouse spleen cells. p ... | 1999 | 10519325 |
| the cloning and sequencing of ribosomal protein s18 of parasitic protozoa, entamoeba histolytica. | a cdna clone encoding ribosomal protein s18 has been isolated from parasitic protozoa, entamoeba histolytica. the cdna insert was 495 nucleotides long and an open reading frame (468 nucleotides including the stop codon) coded for 156 amino acid protein which was highly homologous with human, plant and yeast counterparts. prosite analysis of the ribosomal protein s18 in eukaryote revealed homology with prokaryotic ribosomal protein s13 signature, which is known to be involved in the initiation of ... | 1998 | 10520458 |
| case-control study of enteropathogens associated with childhood diarrhea in dhaka, bangladesh. | the international centre for diarrhoeal disease research, bangladesh, is a major center for research into diarrheal diseases. the center treats more than 100,000 patients a year. to obtain useful information representative of all patients, a surveillance system in which a 4% systematic sample of all patients is studied in detail, including etiological agents of diarrhea, was installed in october 1979. the first paper on etiology for the surveillance patients was published in 1982, which identifi ... | 1999 | 10523534 |
| entamoeba histolytica and entamoeba dispar: epidemiology and comparison of diagnostic methods in a setting of nonendemicity. | recent studies suggest that stool antigen assays are more sensitive and specific than microscopy for the diagnosis of entamoeba histolytica infection. one hundred twelve patients presenting at 3 centers with symptoms or risk factors of e. histolytica infection were prospectively enrolled in this study to evaluate new diagnostic tests for infections with e. histolytica and entamoeba dispar. four elisa-based stool antigen kits for detecting e. histolytica or e. dispar were blindly compared with st ... | 1999 | 10524983 |
| persistent high risk of diarrhea among foreigners in nepal during the first 2 years of residence. | although numerous studies have shown that diarrhea is the most common illness occurring during the first few weeks of travel, systematic studies of the incidence of diarrhea during long-term residence in developing countries have not been performed. we conducted a cohort study of the incidence and etiology of diarrhea among 77 expatriate adults who had lived in nepal for <2 years. persons were followed prospectively for up to 1 year (mean, 9 months). the incidence of diarrhea during the surveill ... | 1999 | 10530456 |
| a dna sequence corresponding to the gene encoding cysteine proteinase 5 in entamoeba histolytica is present and positionally conserved but highly degenerated in entamoeba dispar. | cysteine proteinases of entamoeba histolytica are considered to be one of the most important classes of molecules responsible for the parasite's ability to destroy human tissues. interestingly, one particular cysteine proteinase, located on the surface of e. histolytica trophozoites and designated cysteine proteinase 5 (cp5), is not expressed in the closely related but nonpathogenic species entamoeba dispar. by comparing the e. histolytica and e. dispar genomic loci containing the gene for cp5 ( ... | 1999 | 10531249 |
| molecular mechanisms of pathogenesis in amebiasis. | though both entamoeba histolytica and e. dispar colonize the human gut, only the former is capable of invading tissues and causing disease. although the biology of the parasite and the mechanism of pathogenesis have been intensively studied, there is a lack of consensus about the molecules of e. histolytica that actively participate in pathogenesis. this article reviews some key molecules involved. ga1nac-inhibitable adhesin is a membrane-associated glycoprotein nature, consisting of heavy and l ... | 1999 | 10531719 |
| purification and biochemical characterization of a novel cysteine protease of entamoeba histolytica. | cysteine proteases are important virulence factors of entamoeba histolytica, the causative agent of amoebiasis. a novel cysteine protease from parasite extracts was purified 15-fold by a procedure including concanavalin a-sepharose, hydroxylapatite and deae-sepharose chromatography. the purification resulted in the obtainment of an homogeneous protein with a molecular mass of 66 kda on native page. in 10% sds/page, three bands of 60, 54 and 50 kda were evident. each of the three specific mouse a ... | 1999 | 10542062 |
| characterization of the gene encoding serine acetyltransferase, a regulated enzyme of cysteine biosynthesis from the protist parasites entamoeba histolytica and entamoeba dispar. regulation and possible function of the cysteine biosynthetic pathway in entamoeba. | the enteric protist parasites entamoeba histolytica and entamoeba dispar possess a cysteine biosynthetic pathway, unlike their mammalian host, and are capable of de novo production of l-cysteine. we cloned and characterized cdnas that encode the regulated enzyme serine acetyltransferase (sat) in this pathway from these amoebae by genetic complementation of a cysteine-auxotrophic escherichia coli strain with the amoebic cdna libraries. the deduced amino acid sequences of the amoebic sats exhibite ... | 1999 | 10542289 |
| entamoeba histolytica: a derived, mitochondriate eukaryote? | | 1999 | 10542417 |
| expression, characterization, and crystallization of the pyrophosphate-dependent phosphofructo-1-kinase of borrelia burgdorferi. | the two genes for the putative pyrophosphate-dependent phosphofructokinases (ppi-pfks) of borrelia burgdorferi were cloned by pcr and expressed in escherichia coli, and their protein products were purified to near homogeneity. the larger of the two gene products, a 62-kda protein, is an active ppi-pfk and exists in solution as a dimer. it has apparent k(m) values for fructose 6-p and ppi of 109 and 15 microm, respectively, and a ph optimum of 6.4 to 7.2. the 62-kda protein was crystallized and s ... | 1999 | 10545221 |
| intestinal amebae. | although the intestinal amebae that infect humans are not thought of as classic agents of food-borne disease, food plays an important role in the transmission of these protozoa. this is particularly true for areas of the world where the organisms are endemic. transmission of most intestinal protozoa occurs by the fecal-oral route via contaminated food or water. among the four genera of amebae that infect man, only entamoeba histolytica and blastocystis hominis are causes of disease. this article ... | 1999 | 10549428 |
| early and late endosomal compartments of entamoeba histolytica are enriched in cysteine proteases, acid phosphatase and several ras-related rab gtpases. | pure populations of early and late endosomes of entamoeba histolytica were isolated by magnetic fractionation and characterized. it was shown that these vesicles were enriched in acid phosphatase and cysteine protease activities. an important virulence factor, a 27-kda cysteine protease, was also enriched in early and late endosomes of e. histolytica. these data suggest that e. histolytica hydrolases reside in compartments that are part of or communicate with the endosomal pathway. to begin to i ... | 1999 | 10551365 |
| entamoeba histolytica: surface proteolytic activity and its relationship with in vitro virulence. | we determined the surface-associated proteolytic activity in three entamoeba histolytica schaudinn, 1903 strains (monoxenic hm1, axenic hm1, and hk9) of known virulence and its relationship with collagenase activity. both activities were also determined in axenic hm1 amoebae trophozoites which were sensitive and resistant to complement-mediated lysis. surface proteolytic activity was determined in glutaraldehyde-fixed e. histolytica trophozoites, which degraded the insoluble substrate, hide powd ... | 1999 | 10553649 |
| thermodynamics of target peptide recognition by calmodulin and a calmodulin analogue: implications for the role of the central linker. | the thermodynamics of interaction of two model peptides melittin and mastoparan with bovine brain calmodulin (cam) and a smaller cam analogue, a calcium binding protein from entamoeba histolytica (cabp) in 10 mm mops buffer (ph 7.0) was examined using isothermal titration calorimetry (itc). these data show that cam binds to both the peptides and the enthalpy of binding is endothermic for melittin and exothermic for mastoparan at 25 degrees c. cabp binds to the longer peptide melittin, but does n ... | 1999 | 10561489 |
| antisense inhibition of amoebapore expression in entamoeba histolytica causes a decrease in amoebic virulence. | amoebapores have been proposed to be a major pathogenicity factor of the protozoan parasite entamoeba histolytica, which is responsible for the killing of target cells. these 77-residue peptides are structural and functional analogues of nk-lysin and granulysin of porcine and human cytotoxic lymphocytes. inhibition of amoebapore gene expression in amoebae was obtained following transfection with a hybrid plasmid construct (pap-r2) containing the neo resistance gene and the gene coding for amoeba ... | 1999 | 10564488 |
| dna vaccination with the serine rich entamoeba histolytica protein (srehp) prevents amebic liver abscess in rodent models of disease. | amebiasis remains one of the leading parasitic causes of death worldwide. a vaccine that prevented amebic liver abscess would significantly reduce mortality from this disease. to test the feasibility of a dna vaccine to prevent amebic liver abscess, we immunized both mice and gerbils with plasmid dna encoding the serine rich entamoeba histolytica protein (srehp). animals receiving the srehp dna vaccine developed both antibody and cell mediated immune responses that recognized amebic trophozoites ... | 1999 | 10580200 |
| an improved method to distinguish entamoeba histolytica and entamoeba dispar. | a 482 base pair gene fragment from samples of amoebae e. histolytica and e. dispar was amplified by pcr. the amplification products of fragments from the 2 species of amoebae presented differences in mobility in non-denaturing polyacrylamide gel, probably due to sequence-dependent conformational alterations in the dna fragments. the method described here permits e. histolytica and e. dispar to be distinguished with greater sensitivity and rapidity. | 1999 | 10581613 |
| [amoebic liver abscess in chronic colitis: revision of "crohn disease" diagnosis]. | we present two cases initially diagnosed as crohn's disease which were treated with immunosuppressive drugs. in both patients the development of an amoebic liver abscess led to the correct diagnosis of amoebic dysentery. the pitfalls of the diagnosis of amoebic colitis and the possible influence of immunosuppression in the development of extraintestinal amoebiasis are discussed. | 1999 | 10588024 |
| antimicrobial properties of allicin from garlic. | allicin, one of the active principles of freshly crushed garlic homogenates, has a variety of antimicrobial activities. allicin in its pure form was found to exhibit i) antibacterial activity against a wide range of gram-negative and gram-positive bacteria, including multidrug-resistant enterotoxicogenic strains of escherichia coli; ii) antifungal activity, particularly against candida albicans; iii) antiparasitic activity, including some major human intestinal protozoan parasites such as entamo ... | 1999 | 10594976 |
| invasive amoebiasis: an emerging parasitic disease in patients infected with hiv in an area endemic for amoebic infection. | to describe the incidence and presentations of invasive amoebiasis (ia) in patients with hiv infection in an area endemic for amoebic infection and to assess the role of the indirect haemagglutination (iha) assay in the diagnosis of ia in hiv-infected patients. | 1999 | 10597784 |
| 3'-deoxyribonucleosides and their derivatives as anti-amoebic agents. | in general nucleoside analogues were found to possess in vitro amoebicidal property against trophozoites of entamoeba histolytica. the acid-labile nature of these compounds completely destroyed their ability to cure caecal amoebiasis of rats. however the therapeutic efficacy of one of these compounds yielded most promising results, with 10% cures when it was administered as enteric coated formulation. | 2000 | 10601681 |
| molecular basis of defence against oxidative stress in entamoeba histolytica and giardia lamblia. | gastrointestinal protozoa, viz. entamoeba histolytica and giardia, are able to survive in a microaerobic environment. the role of parasitic factors, particularly cysteine, cysteine-rich proteins, superoxide dismutase, and certain alternative mechanisms, has been described in the defence against oxidative stress. the role of the host-derived factors, particularly the phagocytosis of bacteria or host erythrocytes (intact or their enzymatic/non enzymatic components), in the detoxification of reacti ... | 1999 | 10602671 |
| development of a deltaglna balanced lethal plasmid system for expression of heterologous antigens by attenuated vaccine vector strains of vibrio cholerae. | we have previously shown that more prominent immune responses are induced to antigens expressed from multicopy plasmids in live attenuated vaccine vector strains of vibrio cholerae than to antigens expressed from single-copy genes on the v. cholerae chromosome. here, we report the construction of a deltaglna derivative of v. cholerae vaccine strain peru2. this mutant strain, peru2deltaglna, is unable to grow on medium that does not contain glutamine; this growth deficiency is complemented by pke ... | 2000 | 10603391 |
| innate immunity to amebic liver abscess is dependent on gamma interferon and nitric oxide in a murine model of disease. | evidence from in vitro studies suggests that gamma interferon (ifn-gamma) and nitric oxide (no) are important in host defense against the protozoan parasite entamoeba histolytica. we used scid mice with targeted disruption of the ifn-gamma receptor gene and mice with targeted disruption of the gene encoding inducible no synthase to show that ifn-gamma plays a role in the innate immunity to amebic liver abscess seen in scid mice while no is required for control of amebic liver abscess in immunoco ... | 2000 | 10603416 |
| applying antisense technology to the study of entamoeba histolytica pathogenesis. | | 1999 | 10603478 |
| applying antisense technology to the study of entamoeba histolytica pathogenesis: response | | 1999 | 10603479 |
| prevalence of intestinal parasites among school children in gaza city, gaza strip. | a total of 489 stool specimens were collected from school children aged 6-11 years. the target area is overcrowded, with improper sewage disposal system and low socioeconomic standards. a questionnaire was designed to include relevant informations. each stool specimen was processed by the direct smear microscopy, zinc sulphate flotation technique and formol-ether sedimentation technique. the present study revealed an overall prevalence at 27.6%. six parasites were detected. giardia lamblia (62.2 ... | 1999 | 10605490 |
| differences in substrate specificity and kinetic properties of the recombinant hexokinases hxk1 and hxk2 from entamoeba histolytica. | entamoeba histolytica is responsible for amoebic colitis and liver abscess in humans. entamoeba dispar is a closely related, morphologically indistinguishable nonpathogenic species. the hexokinase (atp:d-hexose 6-phosphotransferase, ec 2.7.1.1) isoenzyme patterns distinguish the pathogenic and nonpathogenic species. both species possess two hexokinases with very similar molecular mass and different isoelectric points. in order to understand the role of the two different isoenzymes from e. histol ... | 2000 | 10613700 |
| lack of a chromosomal copy of the circular rdna plasmid of entamoeba histolytica. | a number of small circular dnas constitute a part of the genome of entamoeba histolytica. among them, the 24.5 kb circular dna encoding rrna (ehr1) is the most abundant. pulsed field gel electrophoresis was used to determine if a chromosomal copy of ehr1 exists and what fraction of the total genome is circular. the results show that the chromosomes of e. histolytica are linear, and that no copy of ehr1 could be detected in any of the linear chromosomes. | 1999 | 10616923 |
| partial characterization of a 36-kda antigen of entamoeba histolytica and its recognition by sera from patients with amoebiasis. | a 36-kda antigen of axenically grown pathogenic entamoeba histolytica (hm1-imss) was eluted from the sodium dodecyl sulfate-polyacrylamide gel electrophoresis (sds-page)-resolved crude amoebic extract antigens. the immunoreactivity of this partially purified 36-kda antigen with monoclonal antibody (moab) 3d(10) altered significantly (p<0.01) after heat and trypsin treatment but remained unaltered after treatment with sodium metaperiodate (p0.5), thereby indicating the protein nature of the epito ... | 2000 | 10617786 |
| application of the polymerase chain reaction (pcr) in the epidemiology of entamoeba histolytica and entamoeba dispar infections. | in this paper, we briefly summarize the latest information on the polymerase chain reaction (pcr) as an epidemiologic tool for entamoeba histolytica and entamoeba dispar infections. this method which employs dna template directly extracted from formalin fixed stool specimens offers a good promise for an accurate and reliable epidemiology of the two species. the assay is, sensitive enough to detect as few as five cysts in the stool sample, rapid and selectively differentiates e. histolytica from ... | 1998 | 10622639 |
| effects of aphidicolin on entamoeba histolytica growth and dna synthesis. | we have detected and characterized dna polymerase activity in cell extracts from trophozoites of entamoeba histolytica and have found that the activity of e. histolytica is inhibited by aphidicolin, which is a specific inhibitor of eukaryotic nuclear replicative dna polymerases. the present study was aimed to evaluate the effect of aphidicolin on growth and dna synthesis by this parasite. aphidicolin blocked the growth of axenic e. histolytica strain hm-1: imss. dna synthesis was also inhibited ... | 1998 | 10622640 |
| [entamoeba histolytica]. | | 1999 | 10635824 |
| extracellular matrix-induced signaling in entamoeba histolytica: its role in invasiveness. | entamoeba histolytica trophozoites can invade the mucosa of the host large intestine to cause disease. here, isaura meza describes recent work indicating that the trophozoites respond to the binding of extracellular matrix proteins by activating receptor-mediated signal transduction pathways. activation of phosphokinase c or adenylyl cyclase induces protein phosphorylation, actin gene expression and reorganization of the actin cytoskeleton to form adhesive structures that promote interaction wit ... | 2000 | 10637584 |
| granulysin: a novel antimicrobial peptide of cytolytic t lymphocytes and natural killer cells. | granulysin is a novel antimicrobial protein produced by human cytolytic t lymphocytes and natural killer cells. it is active against a broad range of microbes, including gram-positive and gram-negative bacteria, fungi, and parasites. the fact that it kills mycobacterium tuberculosis is particularly important, since the current vaccine (bacille calmette-guerin, bcg) is of limited efficacy and antibiotic resistance is increasing. although functionally related to other antibacterial peptides, defen ... | 2000 | 10644038 |
| importance of differentiation of entamoeba histolytica from entamoeba dispar. | | 1999 | 10647224 |
| multifocal omental mesenteric inflammatory pseudotumor (plasma cell granuloma). | inflammatory pseudotumor (ip) is an uncommon benign tumor during childhood. the most common location is lung, and sporadic cases of ip with extrapulmonary involvement such as liver and abdomen are reported. however, the ip among the reported cases have appeared as solitary masses. a multifocal ip in a 14-year-old girl presumed to result following an entamoeba histolytica infestation is reported. | 1999 | 10661859 |
| a subunit vaccine candidate region of the entamoeba histolytica galactose-adherence lectin promotes interleukin-12 gene transcription and protein production in human macrophages. | the cysteine-rich region of the 170-kda subunit galactose-adherence lectin (gal-lectin) of entamoeba histolytica is a subunit vaccine candidate and a protective antigen in the gerbil model of amebiasis. macrophage-mediated immunity is important for protection against e. histolytica and is activated by th1 cytokines. as th1 differentiation is promoted by il-12, we investigated what portion of the gal-lectin could stimulate il-12 in human thp-1 macrophages. native gal-lactin stimulated il-12 p40 / ... | 2000 | 10671197 |
| fluorescence microscopy and fluorescence in situ hybridization of entamoeba histolytica nuclei to analyse mitosis and the localization of repetitive dna. | | 2000 | 10693751 |
| two major 'higher molecular mass proteinases' of entamoeba histolytica are identified as cysteine proteinases 1 and 2. | | 2000 | 10693753 |
| [gastrointestinal diseases associated with hiv infection]. | a clinical studies were carried out on gastrointestinal diseases associated with hiv infection. during the 6 years between january 1993 and december 1998, 71 hiv infected cases visited to yokohama municipal citizen's hospital, and 26 of them developed gastrointestinal complications during the course of their illness. they consisted of 24 males and 2 females, with the mean age of 44.7 years and the medial value of 42.5 years. of the 26 patients, 21 were japanese, and the remaining 5 were southeas ... | 2000 | 10695296 |
| ectonucleotide diphosphohydrolase activities in entamoeba histolytica. | in this work, we describe the ability of living cells of entamoeba histolytica to hydrolyze extracellular atp. in these intact parasites, whose viability was determined by motility and by the eosin method, atp hydrolysis was low in the absence of any divalent metal (78 nmol p(i)/h/10(5) cells). interestingly, in the presence of 5 mm mgcl(2) an ecto-atpase activity of 300 nmol p(i)/h/10(5) cells was observed. the addition of mgcl(2) to the extracellular medium increased the ecto-atpase activity i ... | 2000 | 10700386 |
| rapd in the analysis of isolates of entamoeba histolytica. | genetic variability in entamoeba histolytica was analyzed by random amplified polymorphic dna (rapd) using ten arbitrary primers. due to intrinsic characteristics of the rapd technique only axenic samples were analyzed. since the presence of any microorganism in the cultures interfered in the dna profile by generating rapds not pertaining to e. histolytica. the rapd profiles of e. histolytica samples isolated from patients with different clinical manifestations from different regions of the amer ... | 2000 | 10708008 |
| experimental amebiasis: molecular weight analysis of entamoeba histolytica antigens recognized by igg antibodies. | the reactivity of sera from experimentally infected animal was studied from 5-60 days postinoculation to determine which of the e. histolytica antigens are recognized frequently to infection. crude extract of e. histolytica trophozoites was used and sera were examined by immunoelectrotransference assay. it was observed that sera recognized polypeptide with 70 kda molecular mass after 15 days postinoculation onward and later 14 to 24 polypeptide with molecular weight of 110-22 kda were recognized ... | 1999 | 10709329 |