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Results for “INTESTINAL AMEBIASIS”

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PubMed1997

In vivo and in vitro experimental intestinal amebiasis in Mongolian gerbils (Meriones unguiculatus).

One of the main drawbacks of experimental amebiasis is the lack of an adequate animal model for invasive intestinal lesions. Mongolian gerbils are useful because both intestinal and hepatic amebiasis can be produced experimentally with Entamoeba histolytica trophozoites. In this paper we show results obtained with in vivo and in vitro models of intestinal amebiasis in gerbils. We inoculated gerbils intracecally with monoxenic cultures of a highly virulent E. histolytica HM1:IMSS substrain. In the in vivo model an increase in mucus production was observed during the first 6 h of interaction. Microulcerative mucosal lesions appeared at 24-72 h postinoculation. Inflammatory infiltrate and edema of the lamina propria were associated with superficial foci of necrosis. At 96 h the cecal mucosa had an almost normal appearance and live amebas were no longer detected. In the in vitro model, early damage was detected in cecal strips mounted in Ussing chambers as a rapid fall in potential difference, short-circuit current, and transepithelial resistance that correlated with the extent of the microscopic lesions produced. The latter consisted of cellular edema and the appearance of small, translucent vacuoles at the base of epithelial cells. Further damage led to loss of intercellular junctions, destruction of interglandular epithelial cells, and edema of the lamina propria. The present results demonstrate that the gerbil is useful as an experimental model for the analysis of early stages of invasive intestinal amebiasis both in vivo and in vitro.

Animals↗
PubMed1990

Early expression in mice of genetic resistance to intestinal amebiasis.

Some strains of mice are known to be relatively resistant to hepatic or intestinal amebic infections. In order to know if the intestinal resistance is expressed few hours after infection, we inoculated axenic amebae in three inbred strains of mice either by direct intracecal injection or by infection of a washed-closed cecal loop. We found that amebae do not survive in conventional animals but they colonize longer in animals with the cecal loop. However, the survival was low after 24 hours postinfection. Balb/c mice were more susceptible and CBA mice more resistant. Our results suggest that genetic resistance to intestinal amebiasis is expressed in mice in the early phases of infection.

Animals↗
PubMed1990

[Experimental intestinal amebiasis: invasion and extension of the amebic lesion].

A morphological analysis of an experimental model of invasive intestinal amebiasis was carried out using the washed-closed cecal loop model in hamsters and guinea-pigs. By light microscopy, few amebic trophozoites adhered to the intestinal epithelium, whereas many associated to the mucus blanket. Some trophozoites attached to the interglandular epithelium, during the first 10 to 15 hours of interaction. Hereafter, the parasites destroyed gradually the epithelium and were associated with normal and lysed inflammatory cells. Some amebas have cell debris and erythrocytes in their cytoplasms. Typical amebic ulcer contained abundant trophozoites at the basolateral area. The results suggest that intestinal mucus and muscularis mucosa are temporal barriers to amebic invasion and extension of the ulcer. At the mucosal and submucosal levels, lysis of inflammatory cells produced by amebas seems to play an important role in the extension of the ulcer.

Animals↗
PubMedDate not supplied

[Intestinal amebiasis in Antofagasta, Chile].

In January 1989--December 1991 period we verified 35 cases of symptomatic intestinal amebiasis in Antofagasta, the main city of the North of Chile. Out of the total number of studied patients 23 were adults (77.1% males and 22.9% females) and all of them were permanent residents of Antofagasta. E.histolytica was frequently detected in association with other parasites and/or commensals, and observed alone in only seven cases. The clinical and epidemiological aspects of these 35 cases are discussed.

Adolescent↗
PubMed1995

Intestinal amebiasis: cyclic suppression of the immune response.

The cellular immune response was evaluated in a C3H/HeJ mouse model of intestinal amebiasis at 5-60 days postinoculation with Entamoeba histolytica. At various intervals, spleen lymphocytes were obtained from infected and noninfected control mice and cultured with concanavalin A (Con A), pokeweed mitogen (PWM), or ameba antigen. E. histolytica infection induced a cyclic depression of DNA synthesis when spleen lymphocytes were stimulated with a T-cell mitogen (Con A), a T- and B-cell (PWM) mitogen, or an ameba antigen. A similar response was observed in the determinations of interleukin-2 in the supernatants of Con A-stimulated spleen cells from infected mice. When spleen cells from E. histolytica-infected mice were stimulated with phorbol myristate acetate plus ionomycin, results indicated a signal-transduction defect. These alterations, observed at the cellular level, might facilitate invasion of the host by the parasite.

Animals↗
PubMed1975

Surgical intervention in intestinal amebiasis.

Operative intervention in patients with unrecognized and untreated amebomas or acute fulminating amebic colitis may result in severe complications. Nevertheless, certain clinical presentations of intestinal amebiasis require surgical procedures varying from drainage of an abscess to a subtotal colectomy. If, in patients with acute fulminating amebic colitis, the signs or symptoms of intraperitoneal or impending perforation develop, unremitting diarrhea associated with anemia and hypoproteinemia continues, or localized abscsses fail to improve with chemotherapy, operative intervention is indicated. Complications of amebomas that require operative intervention include failure to respond to chemotherapy, perforation, hemorrhage, ulceration, stricture or fistula formation and obstruction. Anti-amebic chemotherapy can reduce intestinal complications so elective operative procedures should be delayed to allow time for adequate treatment.

Abscess↗
PubMed2001

Diagnosis of intestinal amebiasis using salivary IgA antibody detection.

Attempts were made to use soluble antigen extract of strain HK-9 of Entamoeba histolytica to detect salivary IgA antibodies in intestinal amebiasis patients by using ELISA. Total salivary samples of 109 individuals were divided into four groups. Group I comprised 32 patients whose stools were positive only for E. histolytica cysts and/or trophozoites. Group II comprised 12 individuals whose stools were positive for E. histolytica and other intestinal parasites. Group III comprised 36 individuals whose stools were negative for E. histolytica but contained other intestinal parasites such as E. coli, E. nana, Blastocystis hominis, Trichomonas hominis, Giardia lamblia, Opisthorchis viverrini, and hookworm. Group IV comprised 29 healthy individuals whose stools were free from any intestinal parasitic infections. Based on the mean optical density, OD + 2SD of the results from 29 parasitologically negative healthy individuals, the cut-off OD value for salivary IgA antibodies was 1.265. Therefore, the assays were positive in 14 out of 32 (43.75%) of group I and 2 out of 12 (16.6%) of group II. The assays were positive in 16 out of 36 (44.44%) for group III whereas 2 out of 29 (6.90%) for group IV were positive. The overall sensitivity and specificity of the assays were 36% and 72%, respectively. The false positive rate was 28% and the false negative rate was 64%. The predictive values of positive and negative results were 47% and 63%, respectively. The diagnostic accuracy of ELISA for the presence of salivary IgA antibodies was 58%.

Animals↗
PubMed1996

[Comparison of quinfamide vs etofamide in the Mexican population with intestinal amebiasis].

An open comparative, prospective and randomized study was carried out to evaluate the efficacy and safety of quinfamide and etofamide in the treatment of intestinal amebiasis. This study evaluate two populations: children (1-16 years) and adults (17-80 years). The drugs used were quinfamide at doses of 4.3 mg/kg b.i.d. in children, and 100 mg t.i.d. adults both for one day; and etofamide at doses of 200 mg t.i.d. in children and 500 mg b.i.d. in adults both for three days. A total of 110 patients were included, 54 in the quinfamide group and 56 in the etofamide group. No significant difference between groups in baseline demographics characteristics were observed. Global healing rate for quinfamide group was 87% and for etofamife group was 76.8% (p = 0.0696). This difference was similar considering both group of populations. It is concluded that the therapeutical response was better for the quinfamide group than for the etofamide group. Both drugs have the same safety profile.

Acetamides↗
PubMed1978

[Intestinal amebiasis in children II. Evaluation of various diagnostic technics and different therapeutic regimens].

The diagnostic usefulness of different laboratory tests was evaluated in 20 cases of invasive intestinal amebiasis: the direct coproparasitoscopic exam in mucus obtained by rectoscopy was positive in 90.0 per cent of cases; the same exam done in mucus obtained by the spoon technique was positive in 40.0 per cent. The serum antibodies investigated by the counterimmunoelectrophoresis technique were found in 40.0 per cent of the cases in the first blood sample obtained at the hospital admisssion, and 15 days later this percentage increased to 66.6 percent. The fecal antigen studied by the ELISA technique was positive in 70.0 per cent of the cases. Simultaneously, the therapeutic effectiveness of emetine and metronidazol was evaluated, and with both therapeutic programs total recovery was obtained in 100.0 per cent of the cases; there were no significative differences in the symptoms duration after the start of therapy, and side effects were not observed. The results must be considered preliminary, because the calculated full sample has not been concluded.

Adolescent↗