Identification and characterization of B-cell epitopes of 3FTx and PLA(2) toxins from Micrurus corallinus snake venom.

The main goal of this work was to develop a strategy to identify B-cell epitopes on four different three finger toxins (3FTX) and one phospholipase A2 (PLA2) from Micrurus corallinus snake venom. 3FTx and PLA2 are highly abundant components in Elapidic venoms and are the major responsibles for the toxicity observed in envenomation by coral snakes. Overlapping peptides from the sequence of each toxin were prepared by SPOT method and three different anti-elapidic sera were used to map the epitopes. After immunogenicity analysis of the spot-reactive peptides by EPITOPIA, a computational method, nine sequences from the five toxins were chemically synthesized and antigenically and immunogenically characterized. All the peptides were used together as immunogens in rabbits, delivered with Freund's adjuvant for a first cycle of immunization and Montanide in the second. A good antibody response against individual synthetic peptides and M. corallinus venom was achieved. Anti-peptide IgGs were also cross-reactive against Micrurus frontalis and Micrurus lemniscatus crude venoms. In addition, anti-peptide IgGs inhibits the lethal and phospholipasic activities of M. corallinus crude venom. Our results provide a rational basis to the identification of neutralizing epitopes on coral snake toxins and show that their corresponding synthetic peptides could improve the generation of immuno-therapeutics. The use of synthetic peptide for immunization is a reasonable approach, since it enables poly-specificity, low risk of toxic effects and large scale production.

Stability improvement of the fatty acid binding protein Sm14 from S. mansoni by Cys replacement Structural and functional characterization of a vaccine candidate

The Schistosoma mansoni fatty acid binding protein (FABP), Sm14, is a vaccine candidate against, S. mansoni and F. hepatica. Previously, we demonstrated the importance of a correct fold to achieve protection in immunized animals after cercariae challenge [[10]. C.R.R. Ramos, R.C.R. Figueredo, T.A. Pertinhez, M.M. Vilar, A.L.T.O. Nascimento, M. Tendler, I. Raw, A. Spisni, P.L. Ho, Gene structure and M20T polymorphism of the Schistosoma mansoni Sm14 fatty acid-binding protein: structural, functional and immunoprotection analysis. J. Biol. Chem. 278 (2003) 12745-12751.]. Here we show that the reduction of vaccine efficacy over time is due to protein dimerization and subsequent aggregation. We produced the mutants Sm14-M20(C62S) and Sm14-M20(C62V) that, as expected, did not dimerize in SDS-PAGE. Molecular dynamics calculations and unfolding experiments highlighted a higher structural stability of these mutants with respect to the wild-type. In addition, we found that the mutated proteins, after thermal denaturation, refolded to their active native molecular architecture as proved by the recovery of the fatty acid binding ability. Sm14-M20(C62V) turned out to be the more stable form over time, providing the basis to determine the first 3D solution structure of a Sm14 protein in its apo-form. Overall, Sm14-M20(C62V) possesses an improved structural stability over time, an essential feature to preserve its immunization capability and, in experimentally immunized animals, it exhibits a protection effect against S. mansoni cercariae infections comparable to the one obtained with the wild-type protein. These facts indicate this protein as a good lead molecule for large-scale production and for developing an effective Sm14 based anti-helminthes vaccine.

Infarto agudo de miocardio sin dolor complicando analgesia epidural continua en trauma de tórax / Acute myocardial infarction without pain complicating continuous epidural analgesia in thorax trauma

El objetivo de ésta presentación es describir un caso infrecuente de IAM sin dolor en el curso de traumatismo de tórax mantenido durante un período prolongado con AEC. Los efectos analgésicos de morfina y bupivacaína evitaron el síntoma dolor de isquemia miocárdica y, aunque los anestésicos locales tienen efectos protectores sobre la circulación coronaria, se produjo un evento isquémico severo que puso en riesgo la vida del paciente. Probablemente los pacientes con AEC con alto riesgo de isquemia miocárdica debieran estar monitorizados durante las primeras 36 horas, período en el que se han identificado la mayoría de los eventos isquémicos, que aunque menos frecuentes que con otras formas de analgesia, podría ayudar a identificar a aquellos que están en riesgo elevado de presentar un evento tardío

Infarto agudo de miocardio sin dolor complicando analgesia epidural continua en trauma de tórax / Acute myocardial infarction without pain complicating continuous epidural analgesia in thorax trauma

El objetivo de ésta presentación es describir un caso infrecuente de IAM sin dolor en el curso de traumatismo de tórax mantenido durante un período prolongado con AEC. Los efectos analgésicos de morfina y bupivacaína evitaron el síntoma dolor de isquemia miocárdica y, aunque los anestésicos locales tienen efectos protectores sobre la circulación coronaria, se produjo un evento isquémico severo que puso en riesgo la vida del paciente. Probablemente los pacientes con AEC con alto riesgo de isquemia miocárdica debieran estar monitorizados durante las primeras 36 horas, período en el que se han identificado la mayoría de los eventos isquémicos, que aunque menos frecuentes que con otras formas de analgesia, podría ayudar a identificar a aquellos que están en riesgo elevado de presentar un evento tardío (AU)