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Biomedical subjects

I Suassuna

Publications and source records attributed to I Suassuna.

At least 19 recordsLinked to original sources
PubMed1989

An endocytic process in HEp-2 cells induced by enteropathogenic Escherichia coli.

Infection of HEp-2 cells by enteropathogenic Escherichia coli (EPEC) was examined by transmission and scanning electronmicroscopy. EPEC strains of serogroups O111:K58 and O55:K59 recently isolated from human patients did not exhibit enterotoxic activity, as judged by the Vero-cell and suckling-mouse assays, or invasive ability as judged by the Sereny test. These strains attached to and penetrated HEp-2 cells. Transmission electronmicroscopy showed bacteria in close contact with cell membranes 15 min after infection; later, intense swelling and budding of membranes and penetration of EPEC into the cell cytoplasm occurred. Intracellular bacteria were enclosed in membrane-bound vacuoles in the cell cytoplasm underlying localised adherence sites observed by light microscopy. Scanning electronmicroscopy showed morphologically altered membranes only at the sites of bacterial attachment. Bacteria inactivated by ultraviolet light were not internalised and cytochalasin B (greater than or equal to 10 mg/L) markedly inhibited uptake. These observations suggest that penetration of EPEC into HEp-2 cells occurs by an endocytic process in metabolically active bacteria.

Animals↗
PubMed1986

Evaluation of humoral and cellular immunity in patients with urinary tract infections.

The cellular and humoral immunity of 15 patients with recurrent urinary tract infections was assessed during infection. We determined the reactivity of peripheral blood lymphocytes to microbial antigens (PPD, streptolysin O, tetanus toxoid, Salmonella typhi and Escherichia coli), to allogenic cells, and to mitogens (phytohemagglutinin, concanavalin A, pokeweed mitogen and jacalin). T and B cells were counted by the rosette technique. We also evaluated serum immunoglobulins and C3 and C4 levels by radial immunoprecipitation and specific antibodies for the etiological agent by direct agglutination, hemagglutination and indirect immunofluorescence. Urinary antibodies were assessed by the antibody-coated bacteria test (ACB). Some patients were retested for cellular immune function after cure. No significant alteration of immunoglobulin levels was detected, except for two patients who showed elevated IgM levels. C3 and C4 were elevated in one and in five cases, respectively. Specific serum antibodies for the etiological agent were present in all patients but their levels did not differ from those of normal controls. In only five patients were urinary antibodies detected by the ACB test. Patients' peripheral blood lymphocyte reactivity was depressed during infection for most of the microbial antigens and mitogens tested and returned to normal levels after cure. T and B cell numbers were within the normal range.

Adolescent↗
PubMed1978

Bacteriophage specificity in the identification of Yersinia pestis as compared with other enterobacteria.

Bacteriophage typing of Yersinia pestis and the specificity of the phage among Enterobacteriaceae were investigated. The bacteriophage used for rapid identification of Y. pestis reacted with representative strains of all recognized species of Shigella as well as with Salmonella cholerae-suis. Reactive Shigella serotypes were Sh. dysenteriae 1 and 9, Sh. flexneri 2a, Sh. boydii 1 and 6, and Sh. sonnei. Patterns consisting of isolated plaques (two cases) or absence of plaques were observed when the routine test dilution (RTD) of the phage was used. Results were independent of the incubation temperature (20, 28 or 37 degrees C). Representative strains of Escherichia, Proteus, Providencia and Klebsiella were resistant to the bacteriophage even at 1000 X the RTD established for Y. pestis.

Bacteriophage Typing↗