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antisense inhibition of expression of cysteine proteinases does not affect entamoeba histolytica cytopathic or haemolytic activity but inhibits phagocytosis.inhibition of most of the expression of the cysteine proteinases of entamoeba histolytica strain hm-1:imss was successfully performed by transcription of ehcp5 antisense rna using the promoter of ehg34, which encodes a l21 ribosomal protein of e. histolytica. we have generated a stable transfectant in which the overall level of cysteine proteinase activity is strongly reduced ( 90%). this transfectant has a normal growth rate in diamond's tyi-s-33 medium, a cytopathic and haemolytic activity sim ...19989643545
intestinal parasite infections after extended use of chloroquine or primaquine for malaria prevention.comparative results of baseline and endpoint screening for intestinal parasites are reported from javanese men enrolled in a year-long, placebo-controlled malaria prophylaxis trial in irian jaya. the objective was to detect nontarget qualitative changes that may have resulted from prolonged chloroquine (300 mg base weekly) or primaquine (0.5 mg base/kg daily) prophylaxis. fresh fecal specimens were examined (blinded trial) for parasites and ova using a modified kato-katz thick smear method. more ...19989645872
axenic cultivation of trichomonas vaginalis in a serum-free medium.mammalian serum or bovine serum albumin are essential for trichomonas vaginalis cultivated under axenic conditions. unfortunately, these components inhibit several biological properties of these parasites. pacsr is a serum replacement, free of bovine serum albumin. used for axenic cultivation of entamoeba histolytica. we show that pacsr is also useful for axenic cultivation of t. vaginalis. tubes containing 5.5 ml pehp, or tyi basal media, plus 8% pacsr (v/v), were inoculated with 10(3) trichomo ...19989645876
evaluation of intestinal protozoan morphology in human fecal specimens preserved in ecofix: comparison of wheatley's trichrome stain and ecostain.as a result of disposal problems related to the use of mercury compounds, many laboratories have switched from mercuric chloride-based schaudinn's and polyvinyl alcohol (pva) stool preservatives to other, non-mercury-based preservatives. a comparison of organism recoveries and morphologies of the intestinal protozoa was undertaken with pva containing the ecofix zinc-based schaudinn's preservative (meridian diagnostics, inc.); both wheatley's modification of gomori's trichrome stain (wt) and ecos ...19989650947
role of neutrophils in innate resistance to entamoeba histolytica liver infection in mice.in order to define the role of neutrophils in the innate resistance to entamoeba histolytica liver infection in mice, we examined the pattern of liver lesion induced by direct injection of e. histolytica trophzoites in normal mice and in neutrophil-depleted mice. a variety of histological lesions were found, the extent of liver damage was considerably higher in the neutrophil-depleted mice. livers from neutrophil-depleted mice displayed areas of liquefactive (lytic) necrosis containing a large n ...19989651927
cloning and expression of the entamoeba histolytica erd2 gene. 19989657339
synergy between entamoeba histolytica and escherichia coli in the induction of cytokine gene expression in human colon epithelial cells.entamoeba histolytica induces the expression and secretion of interleukin 8 (il-8) by cultured colon epithelial cells. we assessed the array of cytokine genes expressed by human colon epithelial cells in response to co-culture with e. histolytica trophozoites and tested the hypothesis that enteric bacteria may alter the e. histolytica-induced expression of such genes. ht-29 colon epithelial cells were co-cultured with e. histolytica trophozoites in the presence or absence of escherichia coli. cy ...19989660143
the human monocyte locomotion-inhibitory factor produced by entamoeba histolytica does not inhibit the locomotion of human eosinophils. 19989660147
entamoeba dispar: ultrastructure, surface properties and cytopathic effect.the cytological features of entamoeba dispar, recently recognized by biochemical and molecular biology criteria as a distinct species, were compared to those of entamoeba histolytica when cultured under axenic conditions, living trophozoites of e. dispar strain saw 76orr clone a were more elongated in form, had a single frontal pseudopodium, and showed a noticeable uroid. in sections of e. dispar trophozoites stained with toluidine blue, characteristic areas of cytoplasmic metachromasia were see ...19989669863
case of the season. amebic abscess (entamoeba histolytica) of the liver. 19989583105
slaying the hydra all at once or head by head? 19989585195
entamoeba histolytica induces host cell death in amebic liver abscess by a non-fas-dependent, non-tumor necrosis factor alpha-dependent pathway of apoptosis.amebic liver abscess is characterized by extensive areas of dead hepatocytes that form cavities surrounded by a thin rim of inflammatory cells and few entamoeba histolytica trophozoites. e. histolytica produces pore-forming proteins and proteinases, but how trophozoites actually kill host cells has been unclear. here, we report that e. histolytica induces apoptosis in both inflammatory cells and hepatocytes in a severe combined immunodeficient (scid) mouse model of amebic liver abscess. by study ...19989596776
the small gtp-binding protein racg regulates uroid formation in the protozoan parasite entamoeba histolytica.entamoeba histolytica is a protozoan parasite that invades human intestine leading to ulceration and destruction of tissue. amoebic movement and phagocytosis of human cells is accompanied by characteristic changes in cell morphology. amoebae become polarized, developing a frontal pseudopod and a well-defined rear zone of membrane accumulation designated the uroid. in motile eukaryotic cells, a phenomenon that contributes to movement is the capping of receptors at the cell surface. during the cap ...19989601102
entamoeba histolytica hm1:imss: hemoglobin-degrading neutral cysteine proteases.entamoeba histolytica hmi:imss trophozoites were able to utilize human hemoglobin but not hemin as a sole iron source to grow in vitro. proteases from crude extracts of e. histolytica degraded human, porcine, and bovine hemoglobins at ph 7.0. these proteolytic activities were found by electrophoresis in sds-polyacrylamide gels copolymerized with hemoglobin, with apparent molecular weights of 116, 82, and 21 kda, the 82-kda protein being the most active protease against this substrate. the protea ...19989603491
chromatin organization during the nuclear division stages of live entamoeba histolytica trophozoites. 19989603497
proteinase activity & virulence of entamoeba histolytica on passage through hamster liver.this study was undertaken to determine the enzymatic differences in the process of increasing the degree of virulence in e. histolytica successively passaged in hamster liver. substrate gel electrophoresis was used to compare proteinase banding patterns under reducing conditions from whole cell lysates of one axenic e. histolytica (strain hm1:imss) and five xenic isolates of the same strain of e. histolytica passaged five times through hamster liver. trophozoites successively passaged in hamster ...19989604544
virulence and functions of myosin ii are inhibited by overexpression of light meromyosin in entamoeba histolytica.several changes in cell morphology take place during the capping of surface receptors in entamoeba histolytica. the amoebae develop the uroid, an appendage formed by membrane invaginations, which accumulates ligand-receptor complexes resulting from the capping process. membrane shedding is particularly active in the uroid region and leads to the elimination of accumulated ligands. this appendage has been postulated to participate in parasitic defense mechanisms against the host immune response, ...19989614192
a survey of amoebic infection in the wonji area of central ethiopia.an epidemiological survey to characterize entamoeba histolytica/e dispar isolates from 123 human subjects was carried out in the wonji area of central ethiopia, where an increased incidence of amoebic infection has been reported. in a randomized, coproparasitological study, 93 (75.6%) of the subjects were found positive for at least one species of intestinal parasite: 14 (15.1%) harboured only one species and 79 (84.9%) were infected with at least two species. in-vitro culture in robinson's medi ...19989625913
entamoeba histolytica contains a beta 1 integrin-like molecule similar to fibronectin receptors from eukaryotic cells.entamoeba histolytica trophozoites do interact with extracellular matrix components in order to invade and finally destroy tissue. an important step in this interaction involves the binding of a 140-kda membrane protein that binds to fibronectin. the similarity of this amoebic receptor to fibronectin receptors from higher eukaryotic cells was defined by indirect immunofluorescence, western blot and immunohistochemistry, using polyclonal monospecific antibodies raised against the amoebic protein. ...19989627997
[recommendations for treatment of amebiasis. german society of pediatric infectiology e.v. (dgpi), "parasitology" working group]. 19989629551
amebic liver abscess complicated with cardiac tamponade and mediastinal abscess.amebic pericarditis is an extremely rare complication of liver abscess and an uncommon etiology of sterile pericardial effusion with cardiac tamponade. the association of mediastinal abscess in this clinical setting has not been reported in the literature. herein, we describe a case of amebic liver abscess complicated with mediastinal abscess and amebic pericarditis with cardiac tamponade. a 44-year-old man was admitted to our hospital because of shortness of breath for the previous 2 days. card ...19989549274
entamoeba dispar: cultivation with sterilized crithidia fasciculata.four isolates of entamoeba dispar identified by their hexokinase and phosphoglucomutase isoenzyme profile and by their failure to react with entamoeba histolytica-specific monoclonal antibody (4g6) could be grown in either diamond's bi-s-33 medium, newly developed bcsi-s (biosate cysteine starch iron-serum) medium, or casein-free yi-s medium in the presence of crithidia fasciculata (ref-1:prr) sterilized by heating 56 degrees c for 30 min and subsequent incubation with 1% hydrogen peroxide for 2 ...19989561776
identification of significant variation in the composition of lipophosphoglycan-like molecules of e. histolytica and e. dispar.the lipophosphoglycan-like (lpg-like) molecules of e. histolytica virulent strains are clearly distinct from those of the avirulent e. histolytica and e. dispar strains. abundant 'lpg' levels are apparently limited to virulent strains, while lipophosphopeptidoglycans ('lppg's) are common to both virulent and avirulent strains of e. histolytica and e. dispar. it is therefore conceivable that 'lppg' performs a function that is essential to survival within the host, while the 'lpg' performs a more ...19989561777
molecular analysis of the gal/galnac adhesin of entamoeba histolytica.attachment of entamoeba histolytica to colonic epithelium and a variety of other target cells is mediated by a galactose/n-acetyl d-galactosamine (gal/galnac) inhibitable adhesin. seven monoclonal antibodies specific for nonoverlapping epitopes of the 170 kda subunit have been shown to have distinct effects on adherence. four of these monoclonal antibodies inhibit or have no effect on amebic adherence while two others enhance amebic adherence. the epitopes recognized by these seven monoclonal an ...19989561778
functional heterogeneity of colonic adenocarcinoma mucins for inhibition of entamoeba histolytica adherence to target cells.mucins secreted from the gastrointestinal epithelium from the basis of the adherent mucus layer which is the host's first line of defense against invasion by entamoeba histolytica. galactose and n-acetyl-d-galactosamine residues of mucins specifically inhibit binding of the amebic 170 kda heavy subunit gal-lectin to target cells, an absolute prerequisite for pathogenesis. herein we characterized the secretory mucins isolated from the human colon and from three human colonic adenocarcinoma cell l ...19989561779
the effects of entamoeba histolytica lysates on human colonic mucins.detergent lysates of entamoeba histolytica trophozoites contained high levels of beta-n acetyl-d-glucosaminidase, beta-n acetyl-d-galactosaminidase and alpha-d-galactosidase activity, and lower but significant levels of five other glycosidases. although these activities should have been capable of largely degrading the oligosaccharide side-chains of human colonic mucin, in fact only about one third of high mw mucin was degraded in 72 h and trypsin alone produced a similar effect. there was no ev ...19989561780
molecular changes in entamoeba histolytica in response to bacteria.entamoeba histolytica, the protozoan parasite, is the causative agent of amoebiasis. the degree of virulence, as inferred from invasiveness, of potentially pathogenic strains may be regulated by both host and parasite factors that determine the gut environment. one such factor that plays an important role is the bacterial flora in the gut. previous studies have clearly shown that bacterial flora is an important determinant of virulence in e. histolytica. however, the exact nature of changes indu ...19989561781
[prevalence of antibodies to entamoeba histolytica in the northern area of the province of huelva]. 19989562953
differentiation of pathogenic and non-pathogenic entamoeba: has the question been answered?pathogenic and non-pathogenic entamoeba have been separated into two distinct species. recently, the non-pathogenic e. dispar has been cultivated axenically. however, the genetic variability among different clones from the same strain, experimental production of hybrid clones which may differ from their parents, and the possibility of invasiveness of e. dispar, are some phenomena which may indicate that the last word on distinctiveness of the species has not yet been said.19989563222
isolation of an entamoeba histolytica intracellular alkaline phospholipase a2.the major hemolytic activity of entamoeba histolytica is located in a subcellular fraction called p30. its maximal effect is observed at ph 8.0 and 1 mm ca2+ and is due to a phospholipase a (pla). in the present study a membrane-associated phospholipase a2 was purified from p30 to homogeneity. p30 was fractionated with ethyl ether and the insoluble fraction was extracted with 1 m kcl. the kcl-soluble material was diluted ten times with 0.1 m tris-hcl (ph 9.5) and passed through a chromatofocusin ...19989569097
control of ferredoxin and gal/galnac lectin gene expression in entamoeba histolytica by a cis-acting dna sequence.the ferredoxin (fdx) and lectin (hgl5) promoters of entamoeba histolytica contain the dna sequence motif tattctatt (ure3). previously we showed that mutation of the ure3 motif in the hgl5 lectin promoter results in an increase in promoter reporter activity. mutation of this motif in the fdx promoter led to a 40-to-50% decrease in fdx promoter activity as measured by reporter gene activity and abundance of mrna. e. histolytica nuclear proteins exhibited sequence-specific binding to the ure3 motif ...19989573137
longitudinal study of the antibody response to recombinant entamoeba histolytica antigens in patients with amebic liver abscess.serology is a critical component in the diagnosis of amebic liver abscess. however, in areas endemic for amebiasis there is a high background level of seropositivity for amebiasis (owing to previous infection with entamoeba histolytica), which may complicate the interpretation of a positive serologic test result. recently, we reported that serologic tests based on recombinant e. histolytica antigens might offer improved diagnosis of current invasive amebiasis because they apparently differentiat ...19989574784
entamoeba histolytica: collagen-induced ap-1 dna binding activity.the interaction of entamoeba histolytica trophozoites with collagen induces the synthesis and release of electron-dense granules containing a collagenase activity that is an important factor in the pathogenicity of the parasite. the binding is thought to be mediated by an 'integrin-like' collagen receptor. in the signal transduction mechanisms activated by collagen, pp125fak and p42mapk are involved. using immunoprecipitation assays coupled to western blot analysis, we demonstrate here the colla ...19989580078
modeling of entamoeba histolytica ferredoxin.the e. histolytica ferredoxin (ehfxd) is an iron-sulphur protein and is important in the control of e. histolytica because it donates an electron to and activates metronidazole (4) the most effective anti-amoebic drug. the knowledge of the three-dimensional structure of ehfxd can help to assist in rational design of anti-amebic drugs. homology modeling of ehfxd has been done by using the knowledge of crystal structure of homologous ferredoxin structures. it has been shown that ehfxd is more like ...19989514244
regulation of expression of ribosomal protein l-21 genes of entamoeba histolytica and e. dispar is at the post-transcriptional level.two genes, ehgle3 and ehg34, encoding the ribosomal protein l21 (rp-l21) were identified and characterized from entamoeba histolytica. their coding regions are highly conserved, but their flanking regions differ significantly. analogous genes (edgle3 and edg34) were characterized in e. dispar. the two rp-l21 copies are transcribed at similar levels in the two parasites. however, their relative binding to the polyribosomal complex during active translation is different. in e. histolytica, binding ...19989515695
transcriptional analysis of the ehpgp1 promoter of entamoeba histolytica multidrug-resistant mutant.we present here the cloning and characterization of the ehpgp1 multidrug resistance gene promoter isolated from the entamoeba histolytica drug-resistant mutant clone c2. the ehpgp1 promoter lacks the typical tata box and the transcriptional initiation sequences described for other e. histolytica promoters. the major transcription initiation site of the ehpgp1 gene was located at the atg start codon. the ehpgp1 core promoter located within the first 244 base pairs showed a higher chloramphenicol ...19989516421
transcriptional analysis of the ehpgp5 promoter of entamoeba histolytica multidrug-resistant mutant.we report here the cloning and transcriptional characterization of the ehpgp5 multidrug resistance gene promoter isolated from the drug-resistant clone c2 of entamoeba histolytica. the ehpgp5 promoter has the tata-like motif at -31 base pairs; transcription initiates three nucleotides upstream from the atg in trophozoites grown in 225 microm emetine (clone c2(225)), whereas in those grown without the drug (clone c2) a product with no open reading frame was detected. the promoter was active in tr ...19989516422
cloning and heterologous expression of entamoeba histolytica adenylate kinase and uridylate/cytidylate kinase.we have isolated two cdna clones encoding entamoeba histolytica nucleotide kinases, ehak and ehuk, expressed them in e. coli and performed functional studies of the recombinant enzymes. nucleotide sequence analysis showed that ehak and ehuk genes exhibited the features characteristic of e. histolytica genes, such as transcripts with relatively short 5' and 3' untranslated flanking regions containing the conserved e. histolytica transcription promoter elements located 5' to the initiation codon a ...19989524270
[intestinal parasitic infections in serbia].to determine the public health significance of intestinal parasitism in serbia today, systematic parasitologic examination of 16 regions (kragujevac, luchani, zhagubica, bor, sjenica, novi pazar, valjevo, aleksandrovac, pirot, bosilegrad, ivanjica, golubac, uzhice, kladovo, negotin, beograd) in central serbia were carried out over the period 1984-1993. the study involved a total of 5981 schoolchildren (2887 f, 3094 m), 7-11 years old representing 10% of the total age-matched population (n = 58,2 ...19989525075
entamoeba histolytica: solubilization and biochemical characterization of dolichol phosphate mannose synthase, an essential enzyme in glycoprotein biosynthesis.sequential treatment of trophozoite membranes with the nonionic detergents brij 35 and igepal ca-630 released a soluble fraction that efficiently catalyzed the transfer of mannose from gdp-man into a mannolipid that was identified as dolichol phosphate mannose (dol-p-man) by several criteria. the transfer reaction occurred only in the presence of exogenously added dolichol monophosphate (dol-p). plots of enzyme velocity versus dol-p and gdp-man concentrations revealed sigmoidal and hyperbolic ki ...19989538865
entamoeba infected orbital cysts as a late complication to orbital floor fractures.an unusual late complication to an orbital floor fracture is presented. five years after trauma a now 22-year old man demonstrated an entamoeba infected cyst in the orbit.19989541452
entamoeba histolytica: liver invasion and abscess production by intraperitoneal inoculation of trophozoites in hamsters, mesocricetus auratus.intraperitoneal inoculation of axenically cultured entamoeba histolytica trophozoites constitutes an easy to perform, highly reproducible procedure for inducing amebic liver abscesses in hamsters. efficiency in abscess production (95% of infected animals after 1 week) was similar to data reported using direct intrahepatic or intraportal inoculation. the morphological sequence of infection shows that amebas in the peritoneal cavity initially produce a large exudate constituted mainly of acute inf ...19989501845
entamoeba histolytica and entamoeba dispar are distinct species; clinical, epidemiological and serological evidence.the name of the causative organism of invasive amoebiasis, entamoeba histolytica, was first introduced in 1903, even though this intestinal amoeba had been recognised since 1875. the marked disparity between the number of infected individuals and those with invasive amoebiasis resulted in a number of explanatory hypotheses being proposed. although none of these were universally accepted, brumpt's concept of two morphologically identical species gained increasing acceptance 50-60 years later when ...19989504344
expression and characterization of recombinant pyruvate phosphate dikinase from entamoeba histolytica.the parasite entamoeba histolytica is an organism whose main energetic source comes from glycolysis. it has the singularity that several of its glycolytic enzymes use pyrophosphate as an alternative phosphate donor. thus, pyruvate phosphate dikinase (ppdk), an inorganic pyrophosphate (ppi)-dependent enzyme, substitutes pyruvate kinase present in humans. we previously cloned and sequenced the gene that codifies for ppdk in e. histolytica. we now report its expression in a bacterial system and its ...19989507062
the neutral cysteine proteinase of entamoeba histolytica degrades igg and prevents its binding.patients infected with entamoeba histolytica generate specific igg that does not prevent invasive amebiasis or recurrent infection. studies investigated whether the effectiveness of the human humoral response was limited by cleavage of igg by the extracellular neutral cysteine proteinase of e. histolytica trophozoites, one of the first amebic products to interact directly with components of host defenses. purified proteinase cleaved polyclonal human and monoclonal murine igg in a dose-dependent ...19989466550
comparison of pcr, isoenzyme analysis, and antigen detection for diagnosis of entamoeba histolytica infection.the diagnosis of amebiasis by microscopic identification of the parasite in stool is insensitive and unable to distinguish the invasive parasite entamoeba histolytica from the commensal parasite e. dispar. in this study, we have tested a pcr technique for the detection of e. histolytica and compared it with isoenzyme analysis and the techlab e. histolytica-specific antigen detection test. the nested-pcr test we used is based on amplification of the small subunit rrna gene of e. histolytica and e ...19989466756
mucosal immunogenicity of a holotoxin-like molecule containing the serine-rich entamoeba histolytica protein (srehp) fused to the a2 domain of cholera toxin.one strategy for the induction of mucosal immune responses by oral immunization is to administer the antigen in conjunction with cholera toxin. cholera toxin consists of one a polypeptide (cta) which is noncovalently linked to five b subunits (ctb) via the a2 portion of the a subunit (cta2). coupling of antigens to the nontoxic b subunit of cholera toxin may improve the immunogenicity of antigens by targeting them to gm1 ganglioside on m cells and intestinal epithelial cells. here, we describe t ...19989453596
a new gene family (ariel) encodes asparagine-rich entamoeba histolytica antigens, which resemble the amebic vaccine candidate serine-rich e. histolytica protein.a family of genes, called ariel, are named for and encode asparagine-rich entamoeba histolytica antigens containing 2 to 16 octapeptide repeats. ariel proteins, which are constitutively expressed by trophozoites, belong to a large antigen family that includes the serine-rich e. histolytica protein (srehp), an amebic vaccine candidate.19989423879
cloning and expression of the gene for the active ppi-dependent phosphofructokinase of entamoeba histolytica.pyrophosphate-dependent phosphofructokinase (ppi-pfk) from entamoeba histolytica (hm-1) was purified from trophozoites. oligonucleotide probes based on partial amino acid sequence were used to clone and sequence the gene and the cdna of the enzyme. the molecular mass of the subunit was greater than, and the derived sequence significantly different from, that of the product of the ppi-pfk gene previously cloned from e. histolytica [huang, albach, chang, tripathi and kemp (1995) biochim. biophys. ...19989445396
multiple liver abscesses: an unusual case which demonstrates the importance of ultrasonography in the detection of liver pathology.a 48-year-old caucasian male was admitted to hospital with right-sided chest pain, pyrexia and cough. he had no history of dysentery. he was treated with erythromycin and cotrimoxazole for right lower lobe pneumonia but failed to respond. tender hepatomegaly developed and ultrasound scan demonstrated multiple abscesses in the liver. entamoeba histolytica was identified in his faeces. he was treated with intravenous metronidazole, chloramphenicol and gentamicin and then oral tinidazole, after whi ...199810934548
role of dna probes in characterization of pathogenic and non-pathogenic e. histolytica.various tests have been described to differentiate the pathogenic and non-pathogenic types of e. histolytica. recently dna hybridization has been described to differentiate between the two subtypes. using common hmc probe the presence of e. histolytica in stool was confirmed. then on the basis of hybridization with dna probe p 145 (pathogenic) and b 133 (non-pathogenic) e. histolytica was characterized as being pathogenic and non pathogenic respectively. out of 137 patients studied 88 were sympt ...199811229277
parasitic gut infections.emerging spore-forming protozoa such as cryptosporidia and microsporidia are becoming major public health problems in developing countries as well as in the developed world. they are a new addition to an already long list of intestinal parasites, but their diagnosis is much more difficult than for well-known protozoa and helminths. fortunately, enzyme immunoassay and polymerase chain reaction techniques are becoming available not only for the detection of cryptosporidium parvum and the microspor ...199817033427
resistance to tetracyclines, macrolides, trimethoprim and sulfonamides.tetracyclines are antimicrobial agents that interact with bacterial ribosomes and block protein synthesis. they have activity against a wide range of gram positive, gram-negative, anaerobic and aerobic bacteria, cell-wall free myco plasmas, chlamydiae, mycobacteria, rickettsia, helicobacter, listeria, and protozoan parasites, such as entamoeba histolytica, gzardia lamblia, and plas modiumfalciparum 1-6. tetracyclnes have been extenstvely used in humans for therapy of bacterial respiratory and ur ...199821390769
[selected parasitic and infectious diseases in persons returning from the tropics].due to dramatic development of modern means of transport, exotic countries located on distant continents are today within a few-hour reach by a jet. every year several million people travelled by air in business or as a tourists. this results in easy transmission of parasitic and infectious factors from continent to continent or from country to country. plasmodium vivax infection: diagnosis concerned 6 men who had returned from thailand, india, senegal and zaire. the parasitosis was detected as ...199916886451
[candida and amoebiasis acquired in tropical and subtropical climatic zones].the objective of the study was the analysis of occurrence and number of candida in the alimentary tract of 209 patients with intestinal amoebiasis considering their state after the treatment. amoebiasis was diagnosed on the grounds of entamoeba histolytica present in the faeces, what has just recently been recognised equal to the presence of e. histolytica complex. in all patients serological investigations were performed using indirect haemagglutination (iha) test. the cases with relapses or wi ...199916886471
[acute diarrhea in children less than 3 years of age: enteropathogens isolated in patient's stools, compared with a control group]objectives: to observe the occurrence of different etiological agents of acute diarrhea (ad) in stool specimens of patients and children in a control group. material and methods: 100 children less than three years of age with ad were studied as well as 100 controls, between november 1993 and may 1994. stool specimens were collected in both groups and the following enteropathogens were searched for: rotavirus, escherichia coli (epec, etec, eiec, ehec), salmonella sp, shigella sp, campylobacter je ...199914685548
molecular-based diagnosis of entamoeba histolytica infection. 199914987356
coccidian parasites as a cause of watery diarrhoea among protein energy malnourished and other immunocompromised egyptian children.the role of coccidian parasites in the pathogenesis of watery diarrhea was studied among children with protein energy malnutrition (pem), immunocompromised due to causes other than pem and immunocompetent diarrheic of matched age and sex, as controls. the results showed that the prevalence of infection was 15.48%, cryptosporidium was the most prevalent and showed 14.19% (18.3%, 17.5% and 7.3% in pem, immunocompromised and immunocompetent cases respectively). cyclospora oocysts were detected only ...199912561908
opportunistic intestinal protozoal infections in immunocompromised children.hundred immunocompromised children and 100 house contact controls were chosen. patients included: 52 nephrotic syndrome children receiving corticosteroids for more than one month (age 5.28 +/- 2.32 years), 14 protein-calorie malnutrition (pcm) patients (8 cases of marasmus aged 6 +/- 2.27 months and 6 cases of marasmic kwashiorkor aged 1.39 +/- 0.88 years) and 34 lymphomas patients (22 cases of hodgkin's disease and 12 cases of non-hodgkin's lymphoma; age 4.5 +/- 3.54 years). examination of conc ...199912561933
[a case with amoebic vaginitis]. 199912563761
investigation of an outbreak of amoebiasis in georgia.entamoeba histolytica, a protozoan parasite, occurs worldwide and 12% of the world's population are estimated to be infected. the prevalence of infection varies between 1% in industrialised countries to between 50% and 80% in tropical countries, where tra199912631887
cellular immune response of intracecally inoculated mongolian gerbils with entamoeba histolytica trophozoites.we analyzed the local and systemic cellular immune response in mongolian gerbils inoculated with entamoeba histolytica. two groups were intracecally inoculated with e. histolytica trophozoites and two groups were used as controls. a inoculated groups and a control groups were sacrificed on days 10 and 30 post inoculation (p.i), the spleen and mesenteric lymph nodes (mlns) lymphocytes (ly) were isolated and incubated in vitro with 2 different amebic antigens. the proliferative ly response of inoc ...199910932762
amebiasis: clinical implications of the recognition of entamoeba dispar.entamoeba histolytica was recently reclassified to recognize the existence of two genetically distinct but morphologically indistinguishable species: e. histolytica, the protozoan parasite that causes amebic dysentery and liver abscess, and entamoeba dispar, a nonpathogenic intestinal parasite. acceptance of this redefinition has dramatically changed both our understanding of the true epidemiology of e. histolytica and the optimal methods for diagnosing amebiasis. molecular-based diagnostic test ...199911095821
new insights into the role of the cytoskeleton in phagocytosis of entamoeba histolytica.entamoeba histolytica, a human parasite, crosses the natural barriers of the intestine and, in turn, spreads into the deeper organs, resulting in amoebiasis. the motility of the parasite and its ability to lyse or phagocytose human cells facilitates passage of the amoeba through the intestinal epithelium. little is known about the uptake of material by this parasite; nevertheless, the cytoskeleton is believed to play a role in phagocytosis. myosin ib, an actin-binding protein, localizes to the p ...199911207552
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 ...199910709329
symptomatic and asymptomatic amoebiasis in two heterosexual couples.four cases of amoebiasis are described: two symptomatic with intestinal and hepatic involvement and two asymptomatic, diagnosed in two, heterosexual, italian couples. infection was probably acquired first by the men, via an indirect faccal-oral route, and then transmitted to their partners in the same way. the two amoebic strains isolated, from the woman of one couple and the man of the other, were characterized by electrophoresis as zymodemes ii alpha- and xix of entamoeba histolytica. these fo ...199910715677
the seasonal variation in the microbial agents implicated in the etiology of diarrheal diseases among children in lao people's democratic republic.during 1994-1995, the etiological structure of children's diarrhea was monitored in outpatients at mahosot hospital, vientiane, lao pdr. of the 191 children studied, 42% had stool specimens positive for enteropathogens; 22% had rotavirus, 21.5% enteropathogenic e. coli, 4.7% shigella flexneri, 2.9% campylobacter jejuni, 2.1% shigella sonnei, and 0.5% each of giardia intestinalis and entamoeba histolytica. no vibrio cholerae and salmonella spp. was detected in this monitoring. in children under f ...199910774703
role of dna probes in characterization of pathogenic and non-pathogenic e. histolytica. 199910778707
comparative study of the efficacy and tolerability of secnidazole suspension (single dose) and tinidazole suspension (two days dosage) in the treatment of amebiasis in children.amebiasis caused by entamoeba histolytica may be considered the most aggressive parasitic disease affecting human intestine, causing acute amoebic colitis and extra-intestinal diseases of high morbidity and mortality. 5-nitroimidazoles are the drugs of choice. in this multicenter, open and random clinical trial, the efficacy and tolerability of secnidazole suspension in a single oral dose of 1ml/kg was compared with 0.5ml/kg doses of tinidazole suspension given for 2 consecutive days to 303 enta ...199911098194
physiology and molecular genetics of multidrug resistance in entamoeba histolytica.entamoeba histolytica presents the evolutionarily conserved multidrug-resistance (mdr) phenotype, discovered in mammalian cells. mdr cells overexpress the membrane p-glycoprotein, which excludes unrelated drugs from the cytoplasm. e. histolytica mutants exhibit cross-resistance to unrelated drugs, which are pumped out from the cytoplasm. in drug-resistant trophozoites, the constitutively expressed ehpg1 gene appears to be up-regulated by a c/ebp-like factor and a multiprotein complex that were n ...199911504490
gastrointestinal parasitic infection, anthropometrics, nutritional status, and physical work capacity in colombian boys.this article tests the hypothesis that the presence of gastrointestinal parasites in colombian boys is negatively associated with anthropometric characteristics, physical work capacity, blood hemoglobin (hb) levels, and nutritional status. anthropometric, hb, &vdot;o(2) max, and parasite load data were collected on 1,016 boys in cali, colombia. the boys were classified as lower socioeconomic class (sec) from either urban or rural environments, and upper sec from an urban environment. sixty-three ...199911533992
antisense inhibition of expression of cysteine proteinases affects entamoeba histolytica-induced formation of liver abscess in hamsters.trophozoites of virulent entamoeba histolytica transfected with the antisense gene encoding cysteine proteinase 5 (cp5) have only 10% of the cp activity but retain their cytopathic activity on mammalian monolayers. in the present study we found that the transfected trophozoites with low levels of cp activity were incapable of inducing the formation of liver lesions in hamsters.19999864246
bacterial expression of a neutralizing mouse monoclonal antibody fab fragment to a 150-kilodalton surface antigen of entamoeba histolytica.a mouse monoclonal antibody (mab) (eh3015, igg1 with a k light chain) prepared by hybridoma technology recognizes a 150-kd surface antigen of entamoeba histolytica and inhibits adherence and cytotoxicity of the ameba to mammalian cells. the genes encoding the light chain and the fd region of the heavy chain of the mab were cloned and expressed in escherichia coli. the plasmid used was designed for the expression of fab with a hexa-histidine tag in the periplasmic space. recombinant fab fragments ...19999988319
entamoeba histolytica: signaling through g proteins.the intracellular signaling pathways of entamoeba histolytica are largely unknown. although the expression of guanine nucleotide binding proteins (g proteins) is expected from functional studies, their biochemical characterization remains elusive in this protozoan. using a combination of biochemical and immunological studies, we provide strong evidence for the presence of a gs protein in amoeba. our results strengthen our understanding of the signal transduction mechanisms in e. histolytica as p ...19999990345
hsp60 is targeted to a cryptic mitochondrion-derived organelle ("crypton") in the microaerophilic protozoan parasite entamoeba histolytica.entamoeba histolytica is a microaerophilic protozoan parasite in which neither mitochondria nor mitochondrion-derived organelles have been previously observed. recently, a segment of an e. histolytica gene was identified that encoded a protein similar to the mitochondrial 60-kda heat shock protein (hsp60 or chaperonin 60), which refolds nuclear-encoded proteins after passage through organellar membranes. the possible function and localization of the amebic hsp60 were explored here. like hsp60 of ...199910022906
l-myo-inositol 1-phosphate synthase from entamoeba histolytica.l-myo-inositol 1-phosphate synthase (i-1-p synthase) catalyses the primary reaction for the synthesis of inositol in a variety of prokaryotes, eukaryotes and in the chloroplasts of algae and higher plants. inositol is a precursor of essential macromolecules like membrane phospholipids, gpi anchor proteins and lipophosphoglycans, which play a determinant role in the pathogenesis of protozoan parasites such as leishmania and entamoeba. however, there is no report of i-1-p synthase or its gene from ...199910029310
etiology of outpatient pediatric nondysenteric diarrhea: a multicenter study in the united states.few data have been published recently on the etiology of outpatient pediatric diarrhea in the us.199910048678
isoenzyme and molecular characterization of entamoeba histolytica and entamoeba dispar isolates from symptomatic and asymptomatic subjects.to correlate the clinical features of amebic infections with the characteristics of entamoeba culture isolates of stools.199910063741
prevalence of intestinal parasite infections with special reference to entamoeba histolytica on the island of bioko (equatorial guinea).the prevalence of intestinal parasitic infections was assessed (1993 through 1995) among two different groups of persons on the island of bioko, equatorial guinea. in the first group, parasitologic examinations were performed on stool specimens from a household-based sample of 557 dwellers from the rural area of the island. in the second group, 1,633 inpatients and outpatients at the general hospital of malabo (the capital of the country) were studied. all age groups were represented in both gro ...199910072147
antiamoebic and antigiardial activity of plant flavonoids.the in vitro antiprotozoal activity of 18 natural flavonoids has been determined against entamoeba histolytica and giardia lamblia. (-)-epicatechin, (-)-epigallocatechin and kaempferol were the most active flavonoids against both protozoa.199910083850
myosin ib from entamoeba histolytica is involved in phagocytosis of human erythrocytes.entamoeba histolytica is a protozoan parasite that causes amoebic dysentery in humans. the disease is prevalent worldwide. infection with e. histolytica results in invasion of the intestine by the parasite, followed by tissue damage and inflammation. during this invasive process, parasites kill and phagocytose human epithelial cells, immune cells and erythrocytes. expression of amoebic pathogenicity requires a dynamic cytoskeleton that allows movement, tissue penetration and changes in parasite ...199910085254
characterization of ys-27, an axenic korean strain of entamoeba histolytica.characterization of ys-27, an axenic entamoeba strain, was performed by three different laboratory methods. zymodeme analysis using starch gel electrophoresis and pcr with species-specific primers showed that ys-27 is a pathogenic entamoeba which belongs to the group ii zymodeme. pathogenicity of ys-27 was further confirmed by observing the formation of liver abscess in mongolian gerbils. these results showed that ys-27 is e. hisolytica.199910188386
antiprotozoal properties of helianthemum glomeratum.structure characterization and biological evaluation of the compounds isolated from helianthemum glomeratum, particularly that of the polyphenols, has been the aim of a series of studies carried out to define the further potential use of this plant in the treatment of infectious diarrhoea in children. the flavan-3-ols, (-)-epigallocatechin and (-)-epigallocatechin gallate, isolated from helianthemum glomeratum roots were tested for their antiamoebic and antigiardial effects in vitro. compared wi ...199910190180
[amoebic dysentery]. 199910201245
the tata-box binding protein of entamoeba histolytica: cloning of the gene and location of the protein by immunofluorescence and confocal microscopy.a 309 bp dna fragment from entamoeba histolytica was amplified by pcr using primers derived from the acanthamoeba castellanii consensus tata-box binding protein amino acid sequence. the amplified fragment was used to isolate cdna and genomic dna clones containing an orf encoding the complete e. histolytica tata-box binding protein (ehtbp, 702 bp, 234 aa, molecular mass 26 kda). the ehtbp functional domain showed 55% sequence identity to that of homo sapiens, 54% to a. castellanii and 37% to plas ...199910206708
different antiamebic antibody isotype patterns in the large and small intestine after local and systemic immunization of mice with glutaraldehyde fixed entamoeba histolytica trophozoites.we have determined the major immunoglobulin isotypes (igg, iga, igm) of antiamebic antibodies induced in the serum and in the large and small intestine after local (oral and rectal) or systemic (intraperitoneal and intramuscular) immunization of mice with glutaraldehyde-fixed entamoeba histolytica trophozoites (gft). iga predominated in the small intestine after immunization through all routes, whereas in the large intestine similar antibody levels of the major isotypes were induced by rectal, i ...199910210270
the electrophoretic karyotype of entamoeba histolytica.although knowledge about gene organization and transcription control in the protozoan parasite entamoeba histolytica has increased substantially during the last few years, questions remain open about ploidy, organization and number of chromosomes in this human pathogen. to get insight into these questions conditions were elaborated to consistently separate e. histolytica chromosomes using pulsed-field gel electrophoresis. southern blot analyses indicated variations in number and size of homologo ...199910215023
accuracy of fecal lactoferrin and other stool tests for diagnosis of invasive diarrhea at a colombian pediatric hospital.estimate under "real life" conditions the operating characteristics of several stool tests for determining whether a diarrheal episode is invasive-inflammatory.199910223687
preparation of recombinant human monoclonal antibody fab fragments specific for entamoeba histolytica.genes coding for human antibody fab fragments specific for entamoeba histolytica were cloned and expressed in escherichia coli. lymphocytes were separated from the peripheral blood of a patient with an amebic liver abscess. poly(a)+ rna was isolated from the lymphocytes, and then genes coding for the light chain and fd region of the heavy chain were amplified by a reverse transcriptase pcr. the amplified dna fragments were ligated with a plasmid vector and were introduced into escherichia coli. ...199910225840
down regulation of entamoeba histolytica virulence by monoxenic cultivation with escherichia coli o55 is related to a decrease in expression of the light (35-kilodalton) subunit of the gal/galnac lectin.entamoeba histolytica virulence is related to a number of amebic components (lectins, cysteine proteinases, and amebapore) and host factors, such as intestinal bacterial flora. trophozoites are selective in their interactions with bacteria, and the parasite recognition of glycoconjugates plays an important role in amebic virulence. long-term monoxenic cultivation of pathogenic e. histolytica trophozoites, strains hk-9 or hm-1:imss, with escherichia coli serotype o55, which binds strongly to the ...199910225860
primary sequence of a putative non-atpase subunit of the 26s proteasome from entamoeba histolytica is similar to the human and yeast s2 subunit.the cdna coding for a non-atpase s2 subunit of the 26s proteasome from entamoeba histolytica was cloned from a cdna library (ehs2). the open reading frame has 2529 bp and the deduced amino acid sequence encodes a protein with a calculated molecular mass of 92,000 da. ehs2 has 29-35% identity with the three other known s2 subunit sequences of yeasts and humans.199910227061
serum from entamoeba histolytica-infected gerbils selectively suppresses t cell proliferation by inhibiting interleukin-2 production.suppression of t and b cell responses during invasive amebiasis may be serum mediated. the mechanism of serum-mediated suppression of spleen cell lymphoproliferation from gerbils with amebic liver abscess was examined. compared with uninfected gerbil serum (10%), serum samples collected at days 10, 30, and 60, but not at day 20 after infection, augmented both concanavalin a (con a; t cell mitogen)- and lipopolysaccharide (lps; b cell mitogen)-induced proliferation of homologous spleen cells. onl ...199910228072
biological screening of traditional preparations from some medicinal plants used as antidiarrhoeal in kinshasa, congo.forty six aqueous extracts from 38 medicinal plant species belonging to different families were selected on the basis of their traditional medicinal use as antidiarrhoeic agents. they were submitted in a broad biological screening including antibacterial, antiamoebic and antispasmodic activities. the results of the testing have indicated that 37 extracts (80.43%), 33 (71.74%) and 32 (69.54%) exhibited some level of antibacterial, antiamoebic and antispasmodic activity respectively. only 8 plant ...199910228613
[incidence of intestinal parasites in pediatric patients with hematologic neoplasms from 1 to 15 years of age].reference is made to the most frequent intestinal parasites in the hematologic patients and the association with malnutrition.199910232025
protection of hamsters from amebic liver abscess formation by a monoclonal antibody to a 150-kda surface lectin of entamoeba histolytica.we examined the effects of passive immunization with a monoclonal antibody (eh3015) that recognizes a 150-kda surface lectin of entamoeba histolytica on amebic liver-abscess formation in hamsters. the hamsters were inoculated i.p with 0.1, 1.0, or 10 mg of eh3015 at 24 h prior to an intrahepatic challenge with 10(5) trophozoites of e. histolytica. in hamsters treated with 1.0 and 10 mg of eh3015 the incidence of liver abscesses was significantly reduced. these results demonstrate that monoclonal ...19999950232
detection of circulating antigen in amoebic liver abscess by counter-current immunoelectrophoresis.fifty serum samples from patients with amoebic liver abscess and 50 from subjects who had not suffered from the disease (25 from patients with other, chiefly parasitic, infections and 25 from healthy blood donors, staff or students) were tested for circulating amoebic antigen by counter-current immuno-electrophoresis (ciep). amoebic antigen was detected in 38 sera (76%) from cases of amoebic liver abscess, but in none of the other sera. although ciep is only moderately sensitive, the high specif ...19999920132
infection and immunity mediated by the carbohydrate recognition domain of the entamoeba histolytica gal/galnac lectin.entamoeba histolytica causes invasive amebiasis, a major parasitic disease of the developing world, whose primary symptoms are liver abscess and colitis. all strains of e. histolytica express a 260-kda surface gal/galnac lectin that is antigenically conserved and immunogenic. the lectin is required for adherence to human intestinal epithelial cells and contact-dependent killing of immune effector cells. by expression cloning, the carbohydrate recognition domain (crd) was identified within the le ...19999878032
efficacy of new 5-nitroimidazoles against metronidazole-susceptible and -resistant giardia, trichomonas, and entamoeba spp.the efficacies of 12 5-nitroimidazole compounds and 1 previously described lactam-substituted nitroimidazole with antiparasitic activity, synthesized via srn1 and subsequent reactions, were assayed against the protozoan parasites giardia duodenalis, trichomonas vaginalis, and entamoeba histolytica. two metronidazole-sensitive lines and two metronidazole-resistant lines of giardia and one line each of metronidazole-sensitive and -resistant trichomonas were tested. all except one of the compounds ...19999869568
[entamoeba histolytica]. 199910635824
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 ...199910602671
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