Publications

entamoeba histolytica alters arachidonic acid metabolism in macrophages in vitro and in vivo.	entamoeba histolytica infections are associated with a state of transient suppression of cell-mediated immunity. macrophages, the most important cells in host defence and control of invasive amoebiasis, in infected animals have been found to be deficient in effector functions and accessory cell potential. however, little is known of the cellular mechanisms responsible for the down-regulation. this study investigated whether macrophage dysfunction in amoebiasis is associated with altered macropha ...	1992	1634248
modulation of tumor necrosis factor production by macrophages in entamoeba histolytica infection.	the macrophage-derived mediator tumor necrosis factor alpha (tnf) is a cytokine with pleiotropic effects. tnf exhibits potent immunologic and inflammatory properties in parasitic diseases. the present study examined the production of tnf by macrophages isolated from gerbils infected with entamoeba histolytica and by naive macrophages in response to amoebae in vitro. amoebic liver abscess-derived macrophages produced low constitutive basal levels of tnf; in response to lipopolysaccharide (lps) st ...	1992	1639488
codon usage in entamoeba histolytica.	the codon usage of 10 e. histolytica genes comprising 4455 codons was analysed. the codon usage revealed an extremely biased use of synonymous codons with a preference for nnu (44%) and nna (41.4%) codons. codons cgg (arg), agg (arg) and ccg (pro) were absent in the e. histolytica genes examined. the codon usage of e. histolytica resembled that of plasmodium falciparum.	1992	1639575
the amoeba enigma.	after more than 70 years of intermittent debate over the true relationship between the 'pathogenic' and 'non-pathogenic' forms of entamoeba histolytica, the application of molecular biology has finally yielded an unambiguous answer: these are not interconvertible phenotypes of the same parasite, a kind of unicellular jekyll and hyde, but two quite distinct genetic entities that just happen to look the same. but given the overwhelming evidence now available from gene sequences, pointing to an evo ...	1992	15463553
effect of entamoeba histolytica toxins on isolated human polymorphonuclear leukocytes' phagocytic function.	this study was undertaken to investigate the effect of entamoeba histolytica toxin (ehp/t) obtained from hm1:imss strain on human polymorphonuclear leukocytes (pmns) phagocytic function. a less virulent strain, i.e., nih:200 was also used in this study for comparison. the results revealed that the toxin obtained from the strain hm1:imss inhibited the phagocytic activity of pmns as measured by yeast uptake or chemiluminescence response while the toxin of strain nih:200 did not show any significan ...	1992	17586996
prevalence of intestinal parasites among food handlers in al-medinah.	fecal specimens from 13.216 food handlers (male) adults, representing 21 different nationalities, were analyzed for the presence of intestinal parasites at king abdul azeez hospital, al-medinah. approximately 14% of these individuals harbored potentially pathogenic parasites, the most common organism being giardia lamblia (33%), followed by entamoeba histolytica (23%), trichuris trichiura (12.3%), ascaris lumbricoides (11.8%) and others. the highest incidence of parasite load was found in sri la ...	1992	17589131
prevalence of pathogenic intestinal parasites among preschool children in al-medina district, saudi arabia.	the prevalence of pathogenic intestinal parasites among preschool children in al-medina district, saudi arabia, was determined through a randomized multistage sampling of 8000 preschool children. duplicate specimens from each child were examined using a simple sedimentation technique. the overall prevalence of intestinal parasites among children screened was 18.4%. the most common parasite isolated was giardia lamblia (14.5%). this was followed by entamoeba histolytica (2.7%), enterobius vermicu ...	1993	17590673
entamoeba histolytica as a model for the primitive eukaryotic cell.	entamoeba histolytica is a structurally simple eukaryote lacking mitochondria, peroxisomes and a well-developed golgi apparatus, also in its biochemistry, it deviates substantially from the more complex eukoryotes. these features have alternatively been interpreted as archaic, ie. the ancestor of entamoeba branched off before the primitive eukaryotic cell obtained proto-mitochondria, or as regressive, ie. entamoeba has lost its mitochondria in the course of its adaptation to a parasitic life sty ...	1993	15463662
cell signalling and motility in entamoeba histolytica.	entamoeba histolytica crawls as a polarized cell following external stimuli, with the translocation of signals modifying extracellular matrix interactions and the amoeba cytoskeleton. nancy guillén here describes how the gliding of e. histolytica cells requires the activity of the actomyosin complex, and how actomyosin functions related to motility are necessary for pathogenesis and for amoebal escape from the host immune response.	1993	15463670
a new test for infection by entamoeba histolytica.	entamoeba histolytica is a common parasite of the human intestine, and in a significant percentage of cases it invades the tissues. virulent strains of the organism produce the proteinose histolysain, which almost certainly facilitates the invasive behaviour. histolysoin has been isolated, a selective assay developed, and specific antisera raised against the enzyme. as described here by alfredo luaces, lyda osorio and alan barren, the enzymeba test for infection by e. histolytica combines the sp ...	1993	15463713
surface properties, pathogenicity and differentiation of entamoeba histolytica.		1993	15463760
encystation in entamoeba invadens.	knowledge of the biology and pathogenesis of the human parasite entamoeba histolytica has been limited by the lack of efficient procedures to induce axenic encystation in the laboratory. however, such methods have been developed for e. invadens, a reptilian parasite, for which encystation can be induced by mechanisms that are as yet poorly defined. this has allowed the analysis of some morphological, physiological and biochemical events that accompany differentiation into cysts. elucidation of t ...	1993	15463765
speciation and clonality in entamoeba histolytica.		1993	15463785
activity of a new oxadiazole compound, against experimental infections with entamoeba histolytica and giardia lamblia in animal models.	bti 2286e(+/-)-e-3-(4-methylsulphinylstyryl)-1,2,4-oxadiazole has demonstrated potent amoebicidal activity in a single-dose treatment against entamoeba histolytica infection in the livers of golden hamsters and the caeca of mice, hamsters and rats. it has intra luminal activity against entamoeba criceti, a natural infection in golden hamster, and anti-giardial activity against giardia lamblia infection in suckling mice. bti 2286e is more potent than metronidazole in extra intestinal, intra lumin ...	1993	8561524
production and characterization of monoclonal antibodies against a highly immunogenic fraction of entamoeba histolytica (nih:200) and their application in the detection of current amoebic infection.	six monoclonal antibodies (mabs) were produced against a highly immunogenic fraction derived by the chromatographic separation of the soluble preparation of axenic entamoeba histolytica (strain nih:200) trophozoites. isotype characterization of the six mabs revealed that four belonged to the igm class and one each to the igg1 and the igg2a subclasses. the immunoreactivity patterns and the specificity of the mabs with homologous and heterologous antigens were analyzed by the enzyme-linked immunot ...	1993	8292992
amoebic liver abscess--an unusual presentation.		1993	8294371
correlation between membrane glycoprotein and detergent dissected membrane protein in the assessment of lmif: a report of 51 ala cases.	assessment of 51 amoebic liver abscess cases for leukocyte migration inhibition factor released using membrane glycoprotein and detergent dissected membrane protein (ddmp) of axenic entamoeba histolytica (nih:200). lymphokines release by t lymphocytes in response to purified amoebic membrane glycoprotein (pamg) against whole amoebic lysate (wal), dissect out protein against whole amoebic lysate and membrane glycoprotein against dissected protein was tested by leukocyte migration inhibition test ...	1993	8300172
immunological similarity between the 170 kd amoebic adherence glycoprotein and human beta 2 integrins.	amoebiasis is an important cause of morbidity and mortality in developing countries. virulence of entamoeba histolytica depends on the trophozoite's being able to bind to colonic epithelium; binding is mediated by the 170 kd subunit of a 260 kd lectin. we found, by microcytofluorometry and western blotting studies, that this 170 kd subunit protein shares an epitope with human beta 2 integrins--a subfamily of cell-surface glycoproteins expressed exclusively on leucocytes and involved in many adhe ...	1993	7678048
structural analysis and demonstration of the 29 kda antigen of pathogenic entamoeba histolytica as the major accessible free thiol-containing surface protein.	the 29 kda protein of pathogenic entamoeba histolytica is a cysteine-rich surface antigen which we recently characterized by cdna sequencing and by using monoclonal antibodies which differentiated between pathogenic and non-pathogenic clinical isolates. to determine the structure and biochemical attributes of this protein, a repertoire of immunological techniques using monoclonal antibodies, and radiolabelling were employed. we demonstrated that the 29 kda protein forms a 60 kda dimer and a high ...	1993	7682280
neutralizing monoclonal antibody epitopes of the entamoeba histolytica galactose adhesin map to the cysteine-rich extracellular domain of the 170-kilodalton subunit.	entamoeba histolytica adheres to human colonic mucins and colonic epithelial cells via a galactose-binding adhesin. the adhesin is a heterodimeric glycoprotein composed of 170- and 35-kda subunits. fragments of the hgl1 gene encoding the 170-kda subunit were expressed as recombinant fusion proteins in escherichia coli and reacted with anti-adhesin monoclonal antibodies (mabs) or pooled human immune sera. the mabs tested recognize seven distinct epitopes on the 170-kda subunit and have distinct e ...	1993	7682994
[bacterial, viral and parasitic etiologies of acute infantile diarrhea in a rural senegal].	we have studied the incidence of parasites, viruses and bacteria associated with acute infantile diarrhea in rural senegal. among parasitoses, cryptosporidium parvum (7.7%) is the most frequent, followed by entamoeba histolytica (5.1%). the first bacteriological etiologic agent is escherichia coli (20.9%). rotavirus are also frequently isolated (14.7%). prevalence of pathogens is higher: among children over 6 months and under two years old, among children either with mixed feeding or weaned, dur ...	1993	7758380
diagnostic methods for intestinal parasites in southern iraq with reference to strongyloides stercoralis.	three hundred and thirty-two stool samples were examined for the presence of intestinal parasites including strongyloides stercoralis. each sample was processed and examined by direct smear, formalin-ether and harada and mori culture methods. nine parasites were recovered from patients attending basrah teaching hospital, southern iraq during 1989. the prevalence rate of infection was 64.2%. it was higher in rural (74.2%) than in urban (57.5%) region (p < 0.01). sex distribution was 120 (36.1%) m ...	1993	7939941
[the infectious etiology of acute diarrheal diseases in the republic of cuba, 1991].	this study was carried out in 1991 to learn the behavior of enteropathogenic agents causing acute diarrheal diseases in cuba. 30 children, admitted in hospitals or seen in outpatient services for acute diarrheal diseases, were selected in each province taking into account that they had not received antibiotic or chemotherapy treatments in the previous 72 hours. feces samples were taken from all patients for virological, bacteriological, and parasitological studies, and results were sent to the p ...	1993	7984819
recent trends in the diagnosis of amoebiasis.		1993	8005981
enzyme location and metabolism in entamoeba histolytica.		1993	8032076
[prevalence of enteropathogens in children with liquid diarrhea].	between january 1 and october 31, 1991 148 samples of feces corresponding to the same number of children with acute diarrhea, aged 0-2 years, admitted to hospital o'horan of the secretariat of health in the city of merida, yucatan, mexico, were studied. stools from 105 (70.9%) patients were described as watery diarrhea; from these samples at least one enteric pathogen was detected in 49 (46.6%): a single pathogen was isolated in 37 (35.2%), and mixed infections were observed in 12 (11.4%). we is ...	1993	8066329
an attempt at reversibility and increase of the virulence of axenic strains of entamoeba histolytica.	in this study we have tried to verify whether the interaction "in vitro" with bacteria or small pieces of normal hamster liver would modify the pathogenic behavior of axenic strains of e. histolytica: avirulent ones (icb-32 and icb-rps), of attenuated virulence (icb-csp and hm1) and of mean virulence (icb-462). every attempt to render virulent, recover or increase the virulence of axenic strains of e. histolytica has failed.	1993	7997753
entamoeba histolytica zymodemes in children of osasco, são paulo.		1993	7997764
extra-intestinal amebiasis: clinical presentation in a non-endemic setting.	37/38 patients with reciprocal titers > or = 512 against entamoeba histolytica in denmark over a 5-year period were evaluated retrospectively in order to establish the clinical profile of extra-intestinal amebiasis in a non-endemic area. 24 of these had extra-intestinal amebiasis, all presenting 1 or more amebic liver abscesses on ultrasonography. fever was the most common finding, present in 91% of the cases. the most striking observation was the lack of both abdominal pain and tenderness in 22 ...	1993	8052815
zymodeme alteration of entamoeba histolytica isolates under varying conditions.	cysts of entamoeba histolytica obtained from 2 asymptomatic subjects were cloned in vitro and the isoenzyme patterns and virulence of the cultures derived from them were determined. incubation in diamond's tyi-s-33 medium with crithidia sp. for 80 d resulted in a change from zymodeme iii to zymodeme ii, with consistent virulence. axenization by replacing crithidia sp. with crithidial lysate had no further effect on the zymodeme but the virulence of the amoebae was attenuated. a reversal to zymod ...	1993	8080488
differential effects of the (+)- and (-)-gossypol enantiomers upon entamoeba histolytica axenic cultures.	the in-vitro anti-amoebic effects of (+/-)-, (+)-, (-)-gossypol and emetine were tested against axenic trophozoites from five entamoeba histolytica strains. the (-)-isomer was more active than the racemate and the (+)-isomer. these results indicate that the gossypol anti-amoebic activity is mainly due to its content of (-)-gossypol in all strains tested.	1993	8095532
[intestinal parasite infections in rural students of chiloé archipelago, x region, chile].	in order to contribute to the knowledge of intestinal parasite infection a survey was performed in 462 primary school children from eight rural localities sited in two islands of the chiloe archipelago. stool samples and perianal scotch tape scrapings for intestinal protozoa and helminths were microscopically examined. the prevalence rates of the main species found were: ascaris lumbricoides 43.3%, trichuris trichiura 26.8%, enterobius vernicularis 20.1%, entamoeba histolytica 5.6%, giardia inte ...	1993	8110371
a glyceraldehyde-3-phosphate dehydrogenase with eubacterial features in the amitochondriate eukaryote, trichomonas vaginalis.	glyceraldehyde-3-phosphate dehydrogenase (gapdh), localized in the cytosol of trichomonas vaginalis, was partially purified. the enzyme is specific for nad+ and is similar in most of its catalytic properties to glycolytic gapdhs from other organisms. its sensitivity to koningic acid is similar to levels observed in gapdhs from eubacteria and two orders of magnitude lower than those observed for eukaryotic gapdhs. the complete amino acid sequence of t. vaginalis gapdh was derived from the n-termi ...	1993	8114116
analysis of a polymorphic locus present upstream of rdna transcription units in the extrachromosomal circle of entamoeba histolytica.		1993	8114815
molecular cloning of the gene for a novel abc superfamily transporter of entamoeba histolytica.		1993	8114816
primary structure of the pyruvate phosphate dikinase in entamoeba histolytica.		1993	8114821
analysis of the gene family encoding the entamoeba histolytica galactose-specific adhesin 170-kda subunit.	the 170-kda or heavy subunit of the galactose binding adhesin of entamoeba histolytica is seminal in target cell binding and lysis. to determine the existence and complexity of the 170-kda subunit gene family, hgl, an amebic genomic library in lambda phage was hybridized with dna fragments from the 5' or 3' ends of hgl1. termini from three distinct heavy subunit genes were identified including hgl1, hgl2, and a third, unreported gene designated hgl3. the open reading frame of hgl3 was sequenced ...	1993	8114826
intracellular digestion of human erythrocytes by entamoeba histolytica: a kinetic study in vitro.	the objective of this investigation was to quantitatively evaluate, by using light and transmission electron microscopy, the intracellular digestion of human erythrocytes (he), ingested by entamoeba histolytica trophozoites in vitro. amebas fed 10 min with he were postincubated 3-12 h at 36.5 degrees c without he, and fixed with glutaraldehyde. after staining by the benzidine reaction, he per ameba, and percent of amebas containing at least one he were determined by light microscopy. trophozoite ...	1993	8118158
cutaneous amebiasis in children.	a 7-month-old girl developed cutaneous amebiasis of the perianal and genital areas in association with amebic dysentery. the diagnosis was based on the identification of entamoeba histolytica by skin biopsy. she was treated with dehydroemetine and metronidazole with excellent results. this is only the eighth reported case of this disease in a child.	1993	8302738
the microbiology of acute diarrhoeal disease in the eastern province of saudi arabia.	a prospective study of acute diarrhoeal diseases in the eastern province of saudi arabia was carried out over a 19-month period to determine aetiology, risk factors and other epidemiological characteristics. of the 853 subjects studied, 344 were cases and 509 controls. more cases were seen in children than in adults. enteric pathogens were detected in 49% of the cases, but none in the controls. of the pathogens, 68% were bacterial with salmonella (34%) and shigella species (14.7%) being the most ...	1993	8306900
serologic reactivity to purified recombinant and native 29-kilodalton peripheral membrane protein of pathogenic entamoeba histolytica.	the 29-kda peripheral membrane protein of entamoeba histolytica has recently been demonstrated to have epitopes on pathogenic clinical isolates which were not detected by monoclonal antibodies on nonpathogenic isolates. to analyze the serological response to this protein, we tested 93 serum specimens (from 33 patients with amebic liver abscess, 7 patients with colitis, 2 patients with ameboma, 18 individuals harboring a nonpathogenic zymodeme strain, 10 healthy mexican migrant workers, and 23 he ...	1993	8314979
campylobacter-associated diarrhoea in egyptian infants: epidemiology and clinical manifestations of disease and high frequency of concomitant infections.	a diarrhoeal disease survey in alexandria, egypt determined the prevalence, seasonality, and household risk factors for campylobacter-associated diarrhoea in young children. the study population was 880 children (mean age = 9.8 months) presenting with diarrhoea at one of two hospitals. a control group consisted of 1,079 healthy children (mean age = 8.8 months) attending two nearby vaccination clinics. the overall isolation frequencies for campylobacter spp. were 16.8% for cases and 6.4% for the ...	1993	8315255
early branchings in the evolution of eukaryotes: ancient divergence of entamoeba that lacks mitochondria revealed by protein sequence data.	phylogenetic analyses of ribosomal rna sequences have played an important role in the study of early evolution of life. however, loomis and smith suggested that the ribosomal rna tree is sometimes misleading--especially when g+c content differs widely among lineages--and that a protein tree from amino acid sequences may be more reliable. in this study, we analyzed amino acid sequence data of elongation factor-1 alpha by a maximum likelihood method to clarify branching orders in the early evoluti ...	1993	8315658
31p-nmr analysis of entamoeba histolytica. occurrence of high amounts of two inositol phosphates.	perchloric-acid extracts of axenic entamoeba histolytica were investigated by 31p-nmr spectroscopy. all major 31p resonances observed were assigned to specific compounds. the cells contained inorganic phosphate (1039 nmol/g wet cells), pyrophosphate (16 nmol/g wet cells), nucleoside diphosphates (91 nmol/g wet cells), nucleoside triphosphates (275 nmol/g wet cells), nad(p) (60 nmol/g wet cells), phosphocholine (184 nmol/g wet cells), phosphoethanolamine (214 nmol/g wet cells), cytidine 5'-diphos ...	1993	8319681
interaction between facilitated diffusion of glucose across the plasma membrane and its metabolism in trichomonas vaginalis.	the parasitic protist trichomonas vaginalis transports glucose across the plasma membrane by facilitated diffusion. the km of the transporter for glucose was 1.6 mm. the uptake of labelled glucose in a minimal medium not allowing growth reached saturation only after 2.5 h, indicating the turnover of storage carbohydrate. organisms grown on glucose showed higher activities both of the transporter and of the subsequent metabolic pathway than organisms grown on maltose. at low external glucose conc ...	1993	8319891
effect of recombinant tumor necrosis factor alpha on in vitro amoebicidal activity of murine kupffer cells.	the present study was undertaken to determine whether recombinant tumor necrosis factor alpha (tnf) could induce kupffer cells to kill entamoeba histolytica parasite in vitro. c57bl/6 mice were used in this study. the liver was perfused and kupffer cells harvested and treated with tnf for 6 h. it was found that kupffer cells treated with tnf are able to kill amoebic trophozoites in vitro. these results further show that amoebicidal activity of tnf-activated kupffer cells is dependent on the rati ...	1993	8326852
[carriers and excretors of protozoa].	causative agents of intestinal infections in humans are about 10 pathogenic or facultative pathogenic species of protozoa of which giardia lamblia, entamoeba histolytica, cryptosporidium parvum and enterozytozoon bieneusi are discussed. g. lamblia from humans is morphologically indistinguishable from giardia isolates originating from several species of domestic and wild mammals. swiss giardia isolates of human, sheep, cattle and dog origin could be transmitted to giardia-free rodents and were ra ...	1993	8333895
electrophoretic karyotype and chromosome assignments for a pathogenic and a nonpathogenic strain of entamoeba histolytica.	the electrophoretic karyotypes of a pathogenic and a nonpathogenic strain of entamoeba histolytica were determined by pulsed-field gel electrophoresis. a number of previously isolated genes were assigned to specific chromosomal bands. significant differences between the chromosomal patterns of these strains as well as in the assignment of most genes were found.	1993	8335392
predictive value of diagnostic tests and prevalence of invasive entamoeba histolytica infection.		1993	8335998
human immunodeficiency virus and leprosy.	in summary, clinical leprosy does not appear to be more frequent in hiv-positive than in hiv-negative people in areas where both infections are endemic. there is no evidence that the paucibacillary to multibacillary distribution of patients is altered by hiv infection. there are reports that neuritis is more severe in co-infected people, and that reversal reactions (or, at least, new lesions) may be more frequent after therapy; but these reports are either poorly documented or poorly controlled. ...	1993	8341127
pathogenic entamoeba histolytica: cdna cloning of a histone h3 with a divergent primary structure.	entamoeba histolytica has an unusual nuclear structure characterized by a low degree of chromatin condensation and the absence of stainable metaphase chromosomes. although nucleosome-like particles were observed, no information about histones was available so far. in this paper we describe a cdna clone with significant homology to h3 histones that was isolated from a library of pathogenic e. histolytica. the complete cdna encodes a 15-kda polypeptide, which like the histone sequence from volvox ...	1993	8341328
expression of a recombinant entamoeba histolytica antigen in a salmonella typhimurium vaccine strain.	the expression of a major surface antigen of the intestinal protozoal parasite entamoeba histolytica in an attenuated salmonella typhimurium vaccine strain is described. a polymerase chain reaction fragment derived from cdna encoding the serine-rich entamoeba histolytica protein, srehp, was introduced into s. typhimurium chi 3987 (delta cya delta crp delta asd) using a plasmid expression vector (pya292) containing the aspartate semialdehyde (asd) gene. s. typhimurium expressing recombinant srehp ...	1993	8342325
entamoeba histolytica: the ehzc3 cdna clone encodes a zinc-binding protein.		1993	8344401
improved method for the concentration and purification of faecal cysts of entamoeba histolytica for use as antigen.	human stool samples are the most widely used source of e. histolytica cysts for diagnosis and research. cysts concentrated from faecal samples are contaminated with faecal debris and bacteria and are unsuitable for use as antigens. other gradient purification and sedimentation procedures result in considerable cyst losses. we present an effective and simple purification procedure using varying densities of percoll that yields an adequate cyst concentration from a moderate cyst load in a single s ...	1993	8345546
entamoeba histolytica: antibody response to recent and past invasive events.	sero-epidemiological data from endemic amoebiasis areas are difficult to evaluate because the serology of individuals affected by an active process of entamoeba histolytica tissue invasion is, at present, almost impossible to distinguish from that of individuals who have had an invasive event in the past. the present study compares serum antigenic recognition frequencies among three groups of individuals with different infective conditions: amoebic liver abscess patients; asymptomatic cyst passe ...	1993	8346990
newer stool based diagnostic tests in infectious diseases: possibilities and pitfalls.		1993	8354530
detection of entamoeba histolytica antigens in stool in amebiasis.	stool microscopy, the conventional method of diagnosing intestinal amebiasis, fails to detect entamoeba histolytica in more than 30-40% of clinically suspected cases. demonstration of parasite products in clinical specimens has been suggested as an alternative. however, the usefulness of demonstrating amebic antigen in the stools of clinical cases needs to be assessed.	1993	8354532
imported opisthorchis viverrini and parasite infections from thai labourers in taiwan.	in order to determine the prevalence of intestinal parasites among labourers from thailand in taiwan, the stool samples from 1364 thai labourers were examined by the formalin-ether concentration method and 18.0% were found to be infected with one or more parasites. the infection rates of hookworm, opisthorchis viverrini, strongyloides stercoralis, enterobius vermicularis, ascaris lumbricoides, hymenolepis nana, capillaria philippinensis, schistosoma japonicum, echinostoma sp., entamoeba coli, gi ...	1993	8354853
correlation between antiamoebic igg and autoreactive anti-igg in amoebic liver abscess cases.	igg isolated and purified from a healthy human serum through sephadex g-200 and protein a cl 4b sepharose chromatography was used for detection of its own antibodies and correlated with the antiamoebic antibody titres in amoebic liver abscess cases. the mean titres with standard deviation of the self reactive antibodies to serum igg both ala cases and healthy controls show a highly significant difference, and antiamoebic antibody titres (igg) are very much correlated with the autoreactive anti i ...	1993	8359844
recognition of entamoeba histolytica in liver abscess cases through their specific antiamoebic antibodies.		1993	8359857
serum-independent and serum-dependent cytoadherence in the interaction of entamoeba histolytica with mammalian target cells.	entamoeba histolytica kills target cells only on direct contact, suggesting that trophozoite-mediated cytolysis is initiated by the contact between trophozoites and target cells. we have shown that adherence between e. histolytica and target cells (polymorphonuclear granulocytes, erythrocytes, chinese hamster ovary cells, human colon carcinoma cells) was inhibited by specific carbohydrates, and adherence between e. histolytica and polymorphonuclear granulocytes (pmn) was enhanced by preincubatio ...	1993	8359985
some characteristics of hospitalized hiv seropositive patients in myanmar.	twenty-two hospitalized hiv seropositive patients were studied prospectively between july 1991 and january 1992. the majority of the patients were intravenous drug users (ivdus). their age ranged from 20 to 38 years with a male preponderance of 12 to 1. anemia, lymphopenia and thrombocytopenia were observed in 100%, 36% and 41%, respectively. the common pathogens like malaria parasites, mycobacterium tuberculosis, entamoeba histolytica, streptococcus and salmonella were isolated/identified rathe ...	1993	8362294
analysis of the genomic sequence encoding the 29-kda cysteine-rich protein of entamoeba histolytica.	by analyzing cdna and genomic clones coding for the 29-kda cysteine-rich protein of entamoeba histolytica, substantial sequence differences were found to the 5'-end of a previously described full-length cdna coding for the same protein (reed et al., 1992), which was reported to contain an untranslated 5'-sequence of at least 171 nucleotides, unusual for e. histolytica cdnas. we found evidence that the cdna published by reed et al. (1992) represents a hybridclone composed of two unrelated sequenc ...	1993	8367659
diagnosis of pathogenic entamoeba histolytica infection using a stool elisa based on monoclonal antibodies to the galactose-specific adhesin.	monoclonal antibodies (mabs) directed against pathogen-specific epitopes of the galactose adhesin of entamoeba histolytica were used in an elisa to detect antigen from pathogenic e. histolytica. single stool specimens from 74 patients in bangladesh were used. the elisa for pathogenic e. histolytica was positive in all 12 stool specimens with pathogenic amebae subsequently cultured, in no stool specimens with nonpathogenic e. histolytica and in 2 of 40 stools with other or no intestinal parasites ...	1993	8369019
synthesis, antibacterial and antifungal activity of metal (ii) complexes of 2-acetylpyridine thiosemicarbazones.	2-acetylpyridine-(4-methylthiosemicarbazone), 2-acetylpyridine-(2- methylthiosemicarbazone) and their metal (ii) complexes have been synthesized and characterized by chemical and spectral methods. they were studied for their antibacterial, antifungal and amoebicidal activity in vitro and for their toxicity in vivo. the ligands and their metal (ii) complexes exhibited significant activity against a wide spectrum of microorganisms. the metal (ii) complexes derived from 2-acetylpyridine-(4-methylth ...	1993	8373503
entamoeba histolytica: electrophysiologic and morphologic effects of trophozoite lysates on rabbit colon.	although in acute intestinal amoebiasis the events occurring during the initial interaction of entamoeba histolytica trophozoites with the mucosa of the large intestine probably determine the invasion by the parasites, an appropriate experimental model to study them does not exist. to develop such a model we used rabbit colonic segments (0.28 cm2) mounted in ussing-type chambers. these preparations had electrophysiological properties (potential difference, short-circuit current, and electrical r ...	1993	8375485
entamoeba histolytica proteins modulate the respiratory burst potential by murine macrophages.	reactive oxygen intermediates are important components of macrophage microbicidal mechanisms and pathogenesis of parasitic disease. the purpose of the present study was to investigate the effect of virulent entamoeba histolytica (strain hm1-imss) on respiratory burst potential of macrophages. pretreatment of elicited peritoneal macrophages (epm) with crude soluble amoebic proteins from 1 to 6 hr was found to prime epm for enhanced o2 and h2o2 release in response to phorbol myristate acetate (pma ...	1993	8386134
electron transport components of the parasitic protozoon giardia lamblia.	the energy metabolism of the intestinal parasite, giardia lamblia, involves the iron-sulphur protein, pyruvate:ferredoxin oxidoreductase. cell fractionation studies showed that this enzyme is associated with the membranes. nadh and nadph dehydrogenases were found in both the membrane and cytosolic fractions. epr spectroscopic studies showed the presence of iron-sulphur clusters in the membrane fraction and in the cytosolic fraction, non-sedimentable at 6 x 10(6) g.min. an acidic, soluble protein ...	1993	8391475
entamoeba histolytica cyst passers. clinical profile and spontaneous eradication of infection.	the present study was carried out to examine whether entamoeba histolytica cyst passers suffer from any parasite-related bowel symptoms and to assess the frequency of spontaneous eradication of this infection. the study was carried out in two parts. in part i, stool samples were collected at random from 3536 individuals living in rural communities around delhi. e. histolytica was isolated by the culture technique in 345 (9.7%) subjects. there was no increase in the prevalence rate of bowel sympt ...	1993	8404403
in vitro effect of recombinant interferon gamma in combination with lps on amoebicidal activity of murine kupffer cells.	the present study examines the role of liver macrophages (kupffer cells), of c57bl/6 mice, as effector cells responsible for the killing of entamoeba histolytica trophozoites in vitro. it was shown that unstimulated kupffer cells were inefficient in the killing of e. histolytica trophozoites in vitro. interferon gamma (ifn-gamma) alone was not able to activate kupffer cells to amoebicidal state. however, interferon gamma and lipopolysaccharide (lps) acted synergistically in this phenomenon. it s ...	1993	8406558
in vitro encystation and excystation of entamoeba histolytica trophozoites.		1993	8406604
detection of sialic acid in trophozoites of entamoeba histolytica (nih:200).	in two successive experiments detection of sialic acid was achieved from trophozoites of axenically grown e. histolytica (nih:200) using silicic acid column chromatography for the separation of sialosylated lipids and asialosylated lipids from total lipids. sialic acid of the sialosylated lipids was detected through thiobarbituric acid assay followed by acid hydrolysis. these findings indicate that presence of sialic acid is not only a character of the cystic stage but also that of trophozoites ...	1993	8406633
isoenzyme pattern of clones of entamoeba histolytica.	the isoenzyme pattern of clones of e. histolytica isolated from symptomatic and asymptomatic patients of amoebiasis were determined by starch gel electrophoresis. ten parent cultures (uncloned), 5 from symptomatic and 5 from asymptomatic patients were isolated and established in robinsons medium as xenic cultures. a total of 100 clones were isolated from parent cultures but only 65 could be established. starch gel electrophoresis was carried out on the uncloned and cloned cultures. the analysis ...	1993	8406646
entamoeba histolytica: changes in the zymodeme of cloned nonpathogenic trophozoites cultured under different conditions.	in this paper we report the occurrence of changes in the migration of certain isoenzymes of a cloned strain (mav-cinvestav) of entamoeba histolytica. this strain was isolated from an asymptomatic carrier and showed an initial nonpathogenic zymodeme i. the transfer of polyxenic trophozoites from robinson's medium (7% serum) to jones' medium (30% serum) provoked changes in isoenzyme expression, resulting in the conversion of zymodeme i to a zymodeme that was similar to the xvii zymodeme except for ...	1993	8415539
biochemical and immunological studies on soluble antigens of entamoeba histolytica.	the soluble antigens of entamoeba histolytica trophozoites were analysed in detail by biochemical and immunochemical methods. the antigen was highly complex and heterogeneous as revealed by sephacryl s-300 column chromatography, which showed four distinct fractions. the molecular mass of fractions fi, fii, fiii and fiv was 660, 170, 65 and 13 kda, respectively. protein was the major constituent in crude soluble antigen (csa) and fractions fi and fii (67%, 80% and 90%, respectively). polysacchari ...	1993	8415541
dose- and time-dependent functional and structural damage to the colon mucosa by entamoeba histolytica trophozoite lysates.	analysis of the initial interaction between entamoeba histolytica trophozoites and the large intestine is impossible in humans and very difficult in experimental animals. to circumvent this obstacle we treated the luminal side of full-thickness rabbit colon segments mounted in ussing-type chambers with trophozoite lysates of the e. histolytica hm1 virulent strain. exposure to lysates for up to 90 min produced dose- and time-dependent effects on the colon, consisting of (a) increased decay rates ...	1993	8415570
role of infectious agents in exacerbations of ulcerative colitis in india. a study of clostridium difficile.	fifty patients with idiopathic ulcerative colitis--25 with acute exacerbation of the disease (group i) and 25 in quiescent phase (group ii)--were studied. none of the patients had a history of recent exposure to antimicrobial drugs or hospitalization. evidence of infection with protozoal and bacterial agents and/or presence of clostridium difficile toxin was demonstrated in eight (32%) patients in group i and one (4%) patient in group ii (group i vs. group ii, p < 0.05; chi 2 test with yate's co ...	1993	8421140
molecular characterization of the cdna coding for translation elongation factor-2 of pathogenic entamoeba histolytica.	to investigate the humoral immune response of patients with amoebic dysentry against entamoeba histolytica, immunoglobulin g (igg)-immunopositive cdna clones from the pathogenic strain sfl-3 were examined. a large part of the igg-positive cdna clones obtained with one serum encoded highly conserved intracellular proteins. a clone was found that was homologous to translation elongation factor-2 (ef-2). sequence analysis of the ef-2 cdna showed 63.6% amino acid sequence identity with the human hom ...	1993	8422275
the ca(2+)-atpase activity of entamoeba histolytica is exposed towards the medium and towards the lumen of intracellular vesicles.		1993	8426610
application of the polymerase chain reaction to the epidemiology of pathogenic and nonpathogenic entamoeba histolytica.	we used the polymerase chain reaction (pcr) to study the epidemiology of pathogenic and nonpathogenic entamoeba histolytica in a rural community in mexico. formalin-fixed stool samples were used for extraction of dna. the pcr amplifications were performed using two sets of primers that discriminate between pathogenic or non-pathogenic e. histolytica. a total of 201 randomly selected individuals were studied. among them, 25 (12%) were diagnosed to be infected with e. histolytica by microscopy; pc ...	1993	8427389
localization of myosin heavy chain a in the human pathogen entamoeba histolytica.	to recognize myosin ii in trophozoites of the human pathogen entamoeba histolytica, a specific antimyosin polyclonal serum was raised against a fusion protein consisting of a 146-amino-acid fragment of the myosin ii heavy chain a of e. histolytica (mhca) fused with beta-galactosidase. the hybrid protein was encoded by a chimera gene formed by a dna fragment, from the mhca gene, amplified by polymerase chain reaction and fused with the lacz gene of escherichia coli. polymerase chain reaction-ampl ...	1993	8432587
[febrile status in a traveler returning from the tropics with right-sided upper abdominal pain].	this is a case report of a patient who presented multiple liver abscesses with entamoeba histolytica five weeks after returning from an one-month trip to thailand. this makes clear that a febrile patient returning from the tropics may not only be suspected of malaria, but that we should think about other possible febrile diseases. respecting the incubation period and other clinical symptoms and signs, we are in most of the cases able to reduce the differential diagnosis to only a few possible on ...	1993	8434207
role of cysteine proteinases of entamoeba histolytica on the cytopathogenicity of axenic trophozoites on rat and hamster hepatocytes in vitro.	the role of amebic cysteine proteinase(s) on the in vitro cytotoxic and cytolytic effects of axenic trophozoites of a virulent strain (hm-1) of entamoeba histolytica has been studied using freshly isolated rat and hamster hepatocytes as target cells. the cytotoxic effect was defined as cell killing without loss of cell structure and the cytolytic effect as cell disintegration. incubation experiments of axenic trophozoites with rat or hamster liver cells in the presence and absence of bovine seru ...	1993	8437063
antigenicity, immunogenicity and vaccine efficacy of the galactose-specific adherence protein of entamoeba histolytica.	entamoeba histolytica is an enteric protozoan that causes amoebic colitis and liver abscess. human immunity to e. histolytica is apparently mediated by a serum antibody response and amoebicidal cellular mechanisms. the galactose-specific adherence protein of e. histolytica is a 260 kda glycoprotein which mediates amoebic in vitro adherence to human colonic mucins, epithelium, and inflammatory cells. amoebic lysis of cells is dependent upon binding by this adherence protein. serum igg and salivar ...	1993	8438621
intestinal parasitic infections and urbanization.	about a third of the population in the cities of developing countries live in slums and shanty towns. by the year 2000 it is estimated that this number will grow to 2200 million, and by 2025 about 57% of the population in developing countries will be in urban areas. the prevalence of infections caused by entamoeba histolytica and giardia intestinalis and the prevalence and intensity of ascaris lumbricoides and trichuris trichiura infections may increase among the rural populations who are migrat ...	1993	8440028
sequence of the 5.8s ribosomal gene of pathogenic and non-pathogenic isolates of entamoeba histolytica.		1993	8441643
determination of the pathogenicity of entamoeba histolytica.		1993	8443325
molecular cloning of a rho family gene of entamoeba histolytica.	an entamoeba histolytica gene (eh rho1) was cloned that encodes a putative low-molecular-mass gtp-binding protein, most similar to the ras homologue rho. the eh rho1 open reading frame was 208 amino acids long and encoded a 23-kda protein similar to saccharomyces cerevisiae rho1-rho4 and cdc42 and human rhoa, rac1, and g25k gene products. this similarity was greatest at the nh2 terminus of eh rho1 where two gtp-binding sites and a possible effector site were conserved. a cysteine residue at the ...	1993	8459832
cloning of a virulence factor of entamoeba histolytica. pathogenic strains possess a unique cysteine proteinase gene.	cysteine proteinases are hypothesized to be important virulence factors of entamoeba histolytica, the causative agent of amebic dysentery and liver abscesses. the release of a histolytic cysteine proteinase from e. histolytica correlates with the pathogenicity of both axenic strains and recent clinical isolates as determined by clinical history of invasive disease, zymodeme analysis, and cytopathic effect. we now show that pathogenic isolates have a unique cysteine proteinase gene (acp1). two ot ...	1993	8473498
interaction between trophozoites of entamoeba histolytica and the human intestinal cell line ht-29 in the presence or absence of leukocytes.	studies on the interaction between trophozoites of entamoeba histolytica of pathogenic or non-pathogenic origin and epithelial cells of the human intestine can contribute to the understanding of the pathogenesis of invasive amoebiasis. we have examined the interaction of virulent e. histolytica with the human colonic carcinoma cell line ht-29. differentiated ht-29 cells are comparable to the mucosa cells to which e. histolytica attaches physiologically. adherence between e. histolytica trophozoi ...	1993	8475032
expression of sequences related to c-myc in entamoeba.	the evolutionarily conserved proto-oncogene c-myc is involved in both proliferation and differentiation processes of higher eukaryotic cells. we report here the identification and characterization of sequences homologous to c-myc in different entamoeba species using a fragment of the mammalian c-myc gene as a probe. this probe hybridized with fragments of 3.5 and 3.4 kilobases (kb) in e. histolytica hindiii of ecori digested dna. in e. invadens it recognized fragments of 3.1 and 2.8 kb, and in l ...	1993	8475034
phagocytosis and proteinase activity are not related to pathogenicity of e. histolytica.	to examine the relationship between phagocytosis, proteinase activity and pathogenicity of axenically grown trophozoites of e. histolytica strain hm-1:imss four different cultures were used: (1) a culture preserved in our laboratory for over 4 years, which lost its pathogenicity 3 years ago; (2) a culture passaged several times through hamster liver, which lost its pathogenicity recently; (3) a highly virulent culture supplied by another laboratory; and (4) amebas recovered from hamster liver ab ...	1993	8475035
proteinases resistant to sodium dodecyl sulfate-induced autoproteolysis of entamoeba histolytica hk9 trophozoites.		1993	8475037
complement resistance of pathogenic entamoeba histolytica mediated by trypsin-sensitive surface component(s).	pathogenic forms of the protozoan parasite entamoeba histolytica were reported previously to resist the cytolytic effect of the alternative complement pathway (ap) only temporarily during exposure to complement. in contrast, nonpathogenic forms of e. histolytica had been found to show ap resistance as a stable property. we studied the mechanisms of ap resistance of the two forms. upon exposure to ap activity, resistant pathogenic or nonpathogenic forms bound significantly less c3 products than c ...	1993	8478051
use of a high molecular weight entamoeba histolytica antigen fraction in enzyme-linked immunosorbent assay and thin layer immunoassay tests.	a high molecular weight entamoeba histolytica antigen fraction i was employed for the determination of anti-amoebic antibodies in elisa and thin layer immunoassay (tia) tests. a large number of human serum and immunized guinea pig serum samples were tested against this antigen. in comparison, elisa was found more sensitive than the tia technique. the potent antigen fraction i used in these tests was lyophilized at an optimum concentration of 1 mg/ml for obtaining uniform results.	1993	8481651
nucleotide sequence analysis of the rrna transcription unit of a pathogenic entamoeba histolytica strain hm-1:imss.		1993	8493112
entamoeba histolytica cysts with a defective wall formed under axenic conditions.	axenic hk9 entamoeba histolytica strain amoebae, maintained in pehs medium, displayed several cystic characteristics that involve an active process of cystic wall formation, cellular volume and density diminution, and one or two nuclear divisions. the differentiation process was asynchronic, beginning after the logarithmic growth phase. the axenic cysts, which were maintained in a 50 mosm/kg medium at 4 degrees c for 72 h, produced growing trophozoites within 1-7 days of incubation at 36 degrees ...	1993	8493243
a human cdna corresponding to a gene overexpressed during cell proliferation encodes a product sharing homology with amoebic and bacterial proteins.	a clone, designated pag, was isolated by differential screening of cdna libraries made from the untransformed and ras-transformed human mammary epithelial cell line hbl100. this cdna corresponds to a gene constitutively expressed in most human cells which is induced to higher levels upon serum stimulation in untransformed and ras-transformed hbl100 cells. however, the abundance of the pag transcript is approximately 3-fold higher in transformed as compared to untransformed cells after 7-15 h of ...	1993	8496166
entamoeba histolytica trophozoites: a surface-associated cysteine protease.	the purpose of this work was to define cell surface proteases on entamoeba histolytica trophozoites. molecular sizes of 2-mercaptoethanol-activated proteases were determined in several ameba cell fractions. inhibited proteases were resolved in sds-polyacrylamide gels and then defined by their ability to digest bovine albumin during electrophoretic migration of ameba bands through a stacking gel containing albumin. this second gel revealed nine gaps of digestion along the horizontal albumin line ...	1993	8500583
cloning of the eh cdc2 gene from entamoeba histolytica encoding a protein kinase p34cdc2 homologue.	to understand better growth regulation in the protozoan parasite, entamoeba histolytica (eh), a homologue of the cdc2 gene encoding the yeast cyclin-dependent protein kinase, p34cdc2, has been cloned and sequenced. this gene, called eh cdc2, contains a 79-bp intron located in the same place as the second of four introns in the schizosaccharomyces pombe cdc2 gene. the sequence of an eh cdc2 cdna confirms the conserved eukaryotic splice donor (gt) and acceptor (ag) sites and shows that eh is able ...	1993	8500762