Browsing by Author "BECKER, MI"

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    DEVELOPMENT OF ANTI-HUMAN-B BLOOD GROUP MONOCLONAL-ANTIBODIES SUITABLE AS A BLOOD TYPING REAGENT
    (1994) BECKER, MI; JUICA, F; JAMETT, A; TZICHINOVSKY, S; BARROS, S; AGUAYO, J; DEIOANNES, AE
    An improved procedure for the generation of high-avidity anti-human B blood group monoclonal antibodies (MAbs) was developed. One of them, termed 7A1-2, showed excellent qualities of titer, avidity, and intensity required For use as human B blood typing reagent. Hemagglutination inhibition studies with monosaccharides and oligosaccharides were carried out to determine the specificity of the MAb 7A1-2. These studies indicate that the antibody reacts with the immunodominant region of the antigen which is known to confer the serologic specificity of this blood group.
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    DEVELOPMENT OF HIGHLY SPECIFIC MONOCLONAL-ANTIBODIES FOR THE DIAGNOSIS OF VIBRIO-CHOLERAE-01
    (1995) CASTILLO, L; CASTILLO, D; SILVA, W; ZAPATA, L; REID, M; ULLOA, MT; SEOANE, M; MALDONADO, A; VALENZUELA, ME; BUSTOS, R; TAMPLIN, ML; MARTINEZ, MA; DEIOANNES, AE; JAMETT, A; YUDELEVICH, A; BECKER, MI
    We report here the development of two monoclonal antibodies, termed 5G8 and 5C12, belonging to the IgM and IgG(1) class, respectively, suitable for the identification of Vibrio cholerae 01 in clinical and environmental samples. The specificities of the monoclonals were evaluated by ELISA and indirect immunofluorescent microscopy of microorganisms normally present in stool samples and with two bacterial panels. One panel included 72 potentially antigenically related bacterial strains and the second panel included 20 pathogenic bacterial strains involved in diarrhea cases. The results of these extensive analyses indicate that monoclonal antibodies 5G8 and 5C12 are highly specific and suitable for the clinical diagnosis of Vibrio cholerae 01 inhuman stool samples by indirect immunofluorescent microscopy. Although the antigenic sites recognized by these antibodies were not identified in this study, the observation of Western blot patterns suggested that 5G8 and 5C12 monoclonal antibodies bind to LPS epitopes, a good structural marker for the detection of V. cholerae 01 because it is present in all bacterial cell walls.
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    TOXIC EFFECT OF A PHOTOINDUCED TRYPTOPHAN-RIBOFLAVIN ADDUCT ON F9-TERATOCARCINOMA CELLS AND PREIMPLANTATION MOUSE EMBRYOS
    (1988) SILVA, E; SALIMHANNA, M; BECKER, MI; DEIOANNES, A
    Solutions containing L-tryptophan and riboflavin exposed to visible light, under N2 atmosphere, yield a tryptophan-riboflavin adduct, able to inhibit the growth of cultured F9 teratocarcinoma cells. This same effect was found in the presence of a mixture of the tryptophan photooxidation products and the adduct, when using solutions previously irradiated with visible light in an O2 atmosphere. A cytotoxic effect was also observed with embryos incubated in the presence of a tryptophan-riboflavin adduct, in the latter case necrosis and embryo development arrest occured.
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    VISIBLE-LIGHT EFFECTS ON TUMORAL CELLS IN A CULTURE-MEDIUM ENRICHED WITH TRYPTOPHAN AND RIBOFLAVIN
    (1994) EDWARDS, AM; SILVA, E; JOFRE, B; BECKER, MI; DEIOANNES, AE
    When NSO/2 myeloid cell line and teratocarcinoma F9 cells were irradiated in Dulbecco's modified Eagle medium enriched with tryptophan and riboflavin, toxic photoproducts for these tumoral cells were generated. The active participation of O-1(2) and .OH was established using specific scavengers and quenchers. A cytotoxic effect was also observed when unirradiated tumoral cells were incubated in a previously irradiated culture medium enriched with tryptophan and riboflavin. When irradiated medium was used alone, enriched only with tryptophan or only with riboflavin, no toxic effect was observed. The relevance of charge transfer processes between triplet riboflavin and tryptophan in the generation of cytotoxic photoproducts is discussed.