Publications

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entamoeba histolytica: bacterial expression of a human monoclonal antibody which inhibits in vitro adherence of trophozoites. 200011038321
entamoeba histolytica: deletion of the gpi anchor signal sequence on the gal/galnac lectin light subunit prevents its assembly into the lectin heterodimer.adherence and cytotoxicity of entamoeba histolytica require the function of a heterodimeric galactose and n-acetylgalactosamine (gal/galnac)-specific lectin. the lectin heavy subunit (hgl) contains a carbohydrate recognition domain and mediates inside-out cell signaling via its cytoplasmic tail. the function of the lectin light subunit (lgl) is unknown. the lectin has a unique mechanism of membrane association: hgl is transmembrane but lgl is glycosylphosphatidylinositol (gpi) anchored. the role ...200011038322
[clinical analysis of 36 cases with amebic liver abscess].to investigate the clinical features of amebic liver abscess, the causes of misdignosis and the effect of medical and surgical therapy on patient's prognosis.200012567615
everyday and exotic foodborne parasites.everyday foodborne parasites, which are endemic in canada, include the protozoans entamoeba histolytica, giardia lamblia and cryptosporidium parvum. however, these parasites are most frequently acquired through unfiltered drinking water, homosexual activity or close personal contact such as in daycare centres and occasionally via a food vehicle. it is likely that many foodborne outbreaks from these protozoa go undetected. transmission of helminth infections, such as tapeworms, is rare in canada ...200018159283
protozoan parasites that infect the gastrointestinal tract.protozoa that infect the gastrointestinal tract include the deadly parasite entamoeba histolytica;giardia lamblia, the most common cause of waterborne disease outbreaks; and the large group of spore-forming parasites that share a green algae symbiont and a predilection for causing chronic diarrhea in immunocompromised persons. some recent advances in the epidemiology, pathogenesis, diagnosis, and treatment of the diseases caused by these protozoa are discussed in this review.200017024011
efficacy and safety of quinfamide versus secnidazole in the management of amoebic non-dysenteric colitis in children.to compare the efficacy and safety of single doses of quinfamide and secnidazole in the treatment of amoebic non-dysenteric colitis in children.200023315350
[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
[entamoeba histolytica]. 199910635824
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
molecular-based diagnosis of entamoeba histolytica infection. 199914987356
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
[prevalence of intestinal parasitic disease in three provinces in morocco].a study of intestinal parasites was carried out in taounate, béni mellal and tizinit provinces in morocco on a sample of 1682 individuals who were representative of the urban and rural area population. for each stool specimen, three microscopic examinations and a kato test were performed. in the three provinces, about two-thirds of the study participants from rural areas and around 50% of those from urban areas had parasites. the reproducibility of the prevalence figures allowed the study result ...199910793785
role of protozoa as risk factors for persistent diarrhea.a case control study including 175 children aged 0-36 months suffering from diarrhea of > or = 14 days duration was undertaken to determine whether there is an association between giardia lamblia, entamoeba histolytica or cryptosporidium infection and persistent diarrhea (pd). subjects were identified by ongoing household surveillance and enrolled as cases. for each case two controls were selected by survey of neighbouring households--a child with acute diarrhea and one without diarrhea. both th ...199910798032
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
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
importance of differentiation of entamoeba histolytica from entamoeba dispar. 199910647224
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.199910661859
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.199910616923
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
applying antisense technology to the study of entamoeba histolytica pathogenesis. 199910603478
applying antisense technology to the study of entamoeba histolytica pathogenesis: response 199910603479
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 ...199910605490
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 ...199910523534
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 ...199910524983
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 ...199910530456
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 ( ...199910531249
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 ...199910531719
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 ...199910542062
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 ...199910542289
entamoeba histolytica: a derived, mitochondriate eukaryote? 199910542417
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 ...199910545221
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 ...199910549428
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 ...199910551365
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 ...199910553649
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 ...199910561489
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 ...199910564488
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 ...199910580200
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.199910581613
[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.199910588024
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 ...199910594976
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.199910597784
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
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
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
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
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
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 ...199910518795
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 ...199910519325
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
chitinase secretion by encysting entamoeba invadens and transfected entamoeba histolytica trophozoites: localization of secretory vesicles, endoplasmic reticulum, and golgi apparatus.entamoeba histolytica, the protozoan parasite that phagocytoses bacteria and host cells, has a vesicle/vacuole-filled cytosol like that of macrophages. in contrast, the infectious cyst form has four nuclei and a chitin wall. here, anti-chitinase antibodies identified hundreds of small secretory vesicles in encysting e. invadens parasites and in e. histolytica trophozoites overexpressing chitinase under an actin gene promoter. abundant small secretory vesicles were also identified with antibodies ...199910338523
pantropic retroviral vectors mediate gene transfer and expression in entamoeba histolytica.transformation of entamoeba histolytica has been previously reported, but the foreign genes have all been replicated episomally. pantropic retroviral vectors based on the moloney murine leukemia virus with the envelope glycoprotein of vesicular stomatitis virus (vsv-g) have an extremely broad host range and can be concentrated to high titer. to investigate whether these pseudotyped, pantropic vectors can mediate gene transfer and expression in e. histolytica, we constructed a retroviral vector, ...199910340487
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 ...199910344543
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 ...199910344544
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 ...199910344672
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 ...199910346950
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.199910354892
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 ...199910355798
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 ...199910359300
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 ...199910361303
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 ...199910369416
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.199910372439
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 ...199910375639
sequence-specific 1h, 13c and 15n assignments of a calcium binding protein from entamoeba histolytica. 199910382313
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 ...199910382613
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 ...199910395893
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 ...199910402761
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 ...199910403338
entamoeba dispar contains but does not secrete acid phosphatase as does entamoeba histolytica. 199910403764
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.199910407562
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.199910407569
[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 ...199910410449
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 ...199910411749
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