PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Entamoebiasis”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 163 records · Page 9Linked to original sources
PubMedDate not supplied

Intestinal amoebiasis and giardiasis in southern Indian infants and children.

The role of Entamoeba histolytica and Giardia lamblia as causative agents of paediatric diarrhoea was studied in a southern Indian population. Relationship between infant feeding practices, co-existing malnutrition and the occurrence of intestinal amoebiasis and giardiasis was also examined. The subjects were 361 paediatric patients with acute diarrhoea and 70 hospitalized control children without diarrhoea. Faecal samples from cases and controls were examined for the protozoal pathogens using faecal preservatives, permanent staining and formalin-ether concentration. Bacteriological studies were conducted on 244 of the 361 cases. A high prevalence of invasive amoebiasis was seen in the 0-6 month (12.5%) and 7-12 month (20.3%) age groups. Giardiasis was uncommon under 6 months (2.1%) but occurred in 8-10% of all other age groups. Invasive amoebiasis occurred mainly in children on weaning foods (45.9%) but also [corrected] in exclusively breast-fed children (13.5%). Giardiasis was not seen in exclusively breast-fed infants, but commonly occurred in older children on normal diets. There was no association between amoebiasis or giardiasis and malnutrition.

Age Factors↗
PubMed1990

Missing infections in AIDS.

In north America and Europe, the opportunistic infections from which patients with acquired immune deficiency syndrome (AIDS) frequently suffer are Pneumocystis carinii pneumonia and Mycobacterium avium-intracellulare: in central Africa these infections are uncommon or non-existent. Serious infections with Entamoeba histolytica and Strongyloides stercoralis would be expected to occur in AIDS patients: they do not. Falciparum malaria might be expected to interact with HIV infection: it does not. The epidemiology and pathophysiology of these infections are discussed with respect to HIV co-infection.

Acquired Immunodeficiency Syndrome↗
PubMedDate not supplied

Enzyme-linked immunosorbent assay based on monoclonal and polyclonal antibodies for the detection of Entamoeba histolytica antigens in faecal specimens.

A murine monoclonal antibody (MAb) (Eh208C2-2) raised against crude lysate of the pathogenic HM-1:IMSS strain of Entamoeba histolytica was used in an enzyme-linked immunosorbent assay for the detection of E. histolytica antigens in faecal specimens. The detection limit of the assay was 110 and 280 amoebae/ml of the HM-1:IMSS and HK-9 strains in phosphate-buffered saline, respectively. The assay was applied to single stool samples from 3 groups of individuals comprising 40 patients whose stools were positive for E. histolytica trophozoites and/or cysts (group I), 48 patients whose stools were negative for E. histolytica but positive for other parasites (group II), and 36 parasitologically-negative healthy controls (group III). Positivity rates of 77.5%, 2.1% and 2.7% were found in samples from groups I, II and III respectively. Specificity, positive and negative predictive values, and efficiency of the assay were 97.6%, 93.9%, 90.1% and 91.1% respectively. When group I samples were further divided into a trophozoite-positive subgroup IA (13 samples) and a cyst-positive subgroup IB (27 samples), the positive rates were 100% and 66.7%, respectively (P < 0.025).

Animals↗
PubMedDate not supplied

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 zymodeme III, together with augmentation of virulence, was observed on the 20th day after transfer of axenic amoebae to Diamond's TYSGM-9 medium containing the original bacterial flora. The possibility that the isoenzyme pattern determining the zymodeme and the virulence behave as 2 independent variables in E. histolytica is discussed.

Animals↗
PubMedDate not supplied

Transmission of Entamoeba histolytica within a family complex.

A limited outbreak of symptomatic intestinal and extraintestinal amoebiasis within a family complex is described. The infection was almost certainly transmitted by a Philippino housemaid, who was an asymptomatic carrier of Entamoeba histolytica infection acquired in her native country. Starch-gel electrophoresis showed isoenzyme patterns characteristic of pathogenic zymodeme XIX in all the amoebic isolates.

Adult↗
PubMed1992

Humoral immune response against a 70-kilodalton heat shock protein of Entamoeba histolytica in a group of patients with invasive amoebiasis.

In order to investigate the humoral immune response against Entamoeba histolytica a lambda ZapII cDNA library was constructed from trophozoites of the pathogenic E. histolytica strain SFL-3. The library was screened with serum IgG from a patient with invasive amoebiasis. Forty-nine immunopositive lambda clones were isolated and partial sequences from the inserts were obtained. By comparison of the sequences with the merged database MIPSX from the Martinsried Institute for Protein Sequences we were able to identify homologous proteins for 36 of the clones. Twenty-six of the clones encoded intracellular proteins, among these, the major part (16 clones) were highly homologous to the eukaryotic 70-kDa heat shock proteins (Hsps). The open reading frame of one complete clone encodes a protein of 656 amino acid residues of 71.5 kDa which has 69.8% sequence identity with the human Hsp70 protein. In a larger screening experiment only 3 out of 12 patients detected with their IgG the phage which expressed the 70-kDa heat shock protein(s).

Amino Acid Sequence↗
PubMed1992

Recognition of Entamoeba histolytica lipophosphoglycan by a strain-specific monoclonal antibody and human immune sera.

Western blot analysis showed that the monoclonal antibody 2D7.10 recognized lipophosphoglycan (LPG) from Entamoeba histolytica HM-1:IMSS. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) pattern of [3H]galactose-labeled LPG and Western blot analysis of total lysate of E. histolytica with 2D7.10 revealed patterns similar to that of LPG with 2D7.10. This antibody could also immunoprecipitate purified LPG from the strain HM-1:IMSS after biosynthetically labeling with [3H]galactose and [32P]orthophosphate. However, no immunoprecipitation was observed when 2D7.10 was incubated with [32P]orthophosphate-labeled purified LPG from strain 200:NIH. Sera from patients suffering from invasive amoebiasis also immunoprecipitated 32P-labeled, purified LPG and could immunostain this molecule in Western blots. The human immune sera recognized carbohydrate epitopes but not the associated polypeptides of LPG, as evidenced by sensitivity to periodate digestion, mild acid hydrolysis but not to pronase treatment. It was earlier shown that 2D7.10 binds a carbohydrate epitope in a subset of axenized pathogenic strains of E. histolytica and that this epitope undergoes changes when cultured along with bacteria. These observations suggest that the E. histolytica LPG contains a strain-specific, variable epitope and that LPG is immunogenic in human.

Animals↗
PubMed1994

Identification of a developmentally regulated transcript expressed during encystation of Entamoeba invadens.

Differentiation of trophozoites into cysts in Entamoeba species has been described morphologically and to a lesser extent biochemically, but studies of stage specific gene expression have not been reported. At present Entamoeba invadens is the only species that can be induced to differentiate in axenic culture and is a useful model system for the human parasite Entamoeba histolytica. Using this model system, we performed cDNA-mRNA hybridization experiments to compare the RNA populations from trophozoites and from parasites at different stages of cyst formation. We detected the accumulation of a population of stage specific transcripts between 8 and 22 h after parasites are placed in induction medium. To identify genes involved in the trophozoite-cyst transformation we carried out a differential screening of a cDNA library. This yielded a clone that represents a stage specific gene whose transcripts are barely detectable in vegetatively grown trophozoites and maturing cysts, but are readily detected at the onset of cyst formation. Other features of the gene and its predicted protein product(s) are described.

Amino Acid Sequence↗
PubMed1995

Transient expression of luciferase in Entamoeba histolytica driven by the ferredoxin gene 5' and 3' regions.

We have successfully transfected Entamoeba histolytica trophozoites with constructs containing ferredoxin sequences fused to the reporter gene luciferase. We have determined the conditions and parameters necessary to maximise transient luciferase expression in our system. Our optimal construct gave values of 268 x 10(3) relative light units per second (RLU s-1) when assayed representing a stimulation of 18,000-fold over the control vector. Comparison of differing constructs allowed us to conclude that the 5' and 3' ferredoxin sequences are both necessary for optimal luciferase expression from our vectors. Transcriptional initiation occurs within the consensus sequence ATTCA in both construct and chromosomal ferredoxin promoters.

Animals↗
PubMed1993

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 salivary IgA antibodies from greater than 90% of subjects with invasive amoebiasis recognize the adherence protein's 170 kDa heavy subunit. Incubation of peripheral blood mononuclear cells from antibody-positive subjects with the purified galactose-specific adherence protein induces in vitro T lymphocyte proliferation, IL-2 and gamma interferon production, and direct lymphocyte amoebicidal activity. The rationale for an adherence protein vaccine includes sIgA blockage of amoebic binding to colonic mucins, humoral IgG prevention of parasitic adherence in tissues, and development of amoebicidal cell-mediated immunity. Immunization of gerbils with purified adherence protein in Freund's adjuvant provides protection against intrahepatic challenge with the trophozoites. In summary, the galactose specific adherence protein of E. histolytica contains highly conserved B- and T-cell epitopes, and has a high degree of vaccine efficacy in the gerbil model of amoebic liver abscess.

Animals↗