Publications (6)10.83 Total impact
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Article: Insights on blastomere nuclearity
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ABSTRACT: Purpose: To analyze the results of our transferred embryos, especially those that “changed” their blastomere nuclearity from Multinucleated (MN) to Mono-nucleated during development. Methods: Pregnancies where at least one MN embryo was transferred were retrospectively evaluated and categorized in order to record and follow-up on the ones that were implanted. Embryos were classified as normal (when all blastomeres were mono-nucleated on day one and two of development), corrected (multinucleated embryos on day one that became mono-nucleated on day two) and non-corrected (multinucleated either on day one, on day two or both days). Results: There were 633 transfer cycles analyzed. Thirty-three percent (206) had at least one embryo with a MN blastomere at a given stage of development. Pregnancy and implantation rates were 29.0% and 19.0% for the group of exclusively mono-nucleated embryo transfers, and 28.6% and 15.8% for the group with at least one MN embryo transferred. The pregnancy outcome for “corrected” and “non-corrected” embryos could be corroborated unequivocally in only 9 cases, with an outcome of 8 and 4 normal babies, respectively. Conclusions: Because the amount of data analyzed is not satisfactorily large, differences were not significantly different; however, a trend may exist showing that normal at term pregnancies obtained from corrected embryos are more likely to occur than those from non-corrected embryos. Nuclear observation on a daily basis should be one of the strategies used to select the best embryos for transferring, to improve implantation rates and avoid multiple pregnancies.Journal of Assisted Reproduction and Genetics 04/2012; 24(1):17-22. · 1.84 Impact Factor -
Article: Insights on blastomere nuclearity.
[show abstract] [hide abstract]
ABSTRACT: To analyze the results of our transferred embryos, especially those that "changed" their blastomere nuclearity from Multinucleated (MN) to Mono-nucleated during development. Pregnancies where at least one MN embryo was transferred were retrospectively evaluated and categorized in order to record and follow-up on the ones that were implanted. Embryos were classified as normal (when all blastomeres were mono-nucleated on day one and two of development), corrected (multinucleated embryos on day one that became mono-nucleated on day two) and non-corrected (multinucleated either on day one, on day two or both days). There were 633 transfer cycles analyzed. Thirty-three percent (206) had at least one embryo with a MN blastomere at a given stage of development. Pregnancy and implantation rates were 29.0% and 19.0% for the group of exclusively mono-nucleated embryo transfers, and 28.6% and 15.8% for the group with at least one MN embryo transferred. The pregnancy outcome for "corrected" and "non-corrected" embryos could be corroborated unequivocally in only 9 cases, with an outcome of 8 and 4 normal babies, respectively. Because the amount of data analyzed is not satisfactorily large, differences were not significantly different; however, a trend may exist showing that normal at term pregnancies obtained from corrected embryos are more likely to occur than those from non-corrected embryos. Nuclear observation on a daily basis should be one of the strategies used to select the best embryos for transferring, to improve implantation rates and avoid multiple pregnancies.Journal of Assisted Reproduction and Genetics 02/2007; 24(1):17-22. · 1.84 Impact Factor -
Article: Monochorionic triplets after single embryo transfer.
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ABSTRACT: A 40-year-old patient underwent intracytoplasmic sperm injection and assisted hatching, and a single embryo was transferred. Ultrasonography demonstrated a single gestational sac containing monochorionic tri-amniotic pregnancy. Several factors that have been implicated in the aetiology of monozygotic triple pregnancies after IVF appear to be present in this case. To avoid multiple pregnancies after IVF, it is time to have definite predictive factors for the occurrence of monozygotic multiple pregnancies as well as transferring only a single embryo.Reproductive biomedicine online 11/2004; 9(4):370-1. · 2.04 Impact Factor -
Article: Possible role of cAMP in the differentiation of Trypanosoma cruzi
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ABSTRACT: To assess the possible action of cAMP on the cell differentiation of Trypanosoma cruzi, we determined both cAMP levels and cAMP-binding activities of epimastigotes and trypomastigotes of this parasite. Trypomastigotes showed a 4-fold higher cAMP content and a 2.5-fold increase in the specific activity of a cAMP-binding protein with identical properties to that of epimastigotes. The high levels of cAMP present in trypomastigotes strongly suggest a role of this cyclic nucleotide on the differentiation of T. cruzi.Molecular and Biochemical Parasitology 02/1987; · 2.55 Impact Factor -
Article: Trypanosoma cruzi: polypeptide markers of epimastigotes and trypomastigotes
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ABSTRACT: We compared the major polypeptides of epimastigotes and trypomastigotes of T. cruzi., by submitting total parasite lysates to electrophoresis in polyacrylamide gels (SDS-PAGE), protein staining with Coomassie brilliant blue, laser densitometry, or immunoblotting with sera derived from infected individuals (Chagas' disease). Epimastigotes and trypomastigotes displayed extensive homology, the differences being quantitative, except for a trypomastigote-specific band of Mr 75 000 which reacted with chagasic sera. Immunoblotting with chagasic sera confirmed the electrophoretic homology of epimastigotes and trypomastigotes. Upon antigenic dilution, a cluster of antigenic bands in the range of Mr 150 000 to 75 000 prevailed in the trypomastigotes, whereas the epimastigotes displayed more abundance of antigenic bands in the range of Mr 72 000 to 36 000.Molecular and Biochemical Parasitology 08/1986; · 2.55 Impact Factor -
Article: Cloning and sequencing of a 24-kDaTrypanosoma cruzi specific antigen released in association with membrane vesicles and defined by a monoclonal antibody
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ABSTRACT: In the present study we have used the Tcr7 monoclonal antibody (mAb) previously characterized as directed againstTrypanosoma cruzi 24–25-kDa specific antigens, both are immunogenic in man and during experimentalT cruzi infections. We have demonstrated that mAb Tcr7 was able to recognize twoin vitro translation products of molecular weights of 24 and 25 kDa. This suggested the holoproteic nature of these two related antigens bearing at least a common epitope and allowed us to use Tcr7 for an immunoscreening of a lambda ZAPIIT cruzi cDNA library. Indeed, we have obtained several positive clones and completly sequenced the largest one which encoded theoretically for a protein of 23.7 kDa. The sequence analysis revealed a nearly perfect homology between this clone and one already described by other investigators and was shown to express a major flagellar protein ofT cruzi able to bind calcium. Using different overlapping peptides derived from the sequence of the cDNA clone, we have localized the immunoreactivity of mAb Tcr7 mainly on several primary sequences present in the N-terminal part of the sequence, suggesting that the mAb could recognize a discontinuous epitope. Moreover, the immunoelectron microscopy allowed us to show that the antigen(s) carrying the epitope reacting with mAb Tcr7 is (are) released in association with membrane vesicles which protruded from the parasite surface and the flagellar pocket. This new mechanism of antigen shedding is likely to be independent of phospholipase C-mediated release of GPI-anchored molecules.Biology of the Cell.
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1987–2012
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Centro Médico Docente La Trinidad
Caracas, Distrito Capital, Venezuela
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