Estado antioxidante do sangue como indicador da eficiência do treinamento em nadadores / Blood antioxidant status: a parameter to stablish the swimmer perfomance

A prática regular de exercícios deve levar à regulaçäo da atividade das enzimas antioxidante do músculo esquelético e os oxidantes atuariam como indutores de tal efeito. O principal objetivo deste estudo foi determinar respostas metabólicas adaptativas ao estresse oxidativo em nadadores antes e após um período de treinamento. O estudo foi realizado com doze atletas da equipe de nataçäo do Yara Clube de Marília, submetidos a um período de trinta dias de treinamento, seis vezes por semana. Os resultados demonstraram que exercícios de intensidade variável foram associados com reduçäo na capacidade antioxidante do plasma e respostas adaptativas no sistema da GSH juntamente com a regulaçäo positiva da atividade da SOD eritrocítica. Portanto, concluímos que o exercício físico prolongado em atletasmoderadamente treinados, desenvolve uma resposta do sistema antioxidante numa tentativa de suplantar a geraçäo de radicais livres advindos do metabolismo oxidativo e que o estado antioxidante intraeritrocítico e do plasma säo eficientes indicadores do estresse oxidativo.

Polyclonal B-cell activation by Neisseria meningitidis capsular polysaccharides elicit antibodies protective against Trypanosoma cruzi infection in vitro.

A hyperimmune rabbit antiserum against group C Neisseria meningitidis agglutinated and lysed Trypanosoma cruzi metacyclic trypomastigotes in a complement-mediated reaction. Immunization of rabbits with the purified polysaccharide C from N. meningitidis and of human volunteers with the AC-polysaccharide vaccine against meningitis also resulted in antibody production cross-reactive with T. cruzi infective forms. The rabbit antibodies bound to parasites, lysed metacyclic forms, and recognized several components from lysates of cell-derived trypomastigotes. The sera from six human volunteers reacted with cell-cultured trypomastigotes in vitro, lysed these forms, and recognized glycoconjugates migrating diffusely on the top of immunoblots. One serum also reacted with the isolated mucin-like glycoconjugate carrying the Ssp-3 epitope from cell-derived trypomastigotes, but treatment with sialidase did not abolish this reactivity. The anti-AC human antiserum also protected against HeLa cell infection and markedly decreased the number of parasites liberated after cell burst. The polyclonal response that resulted from human immunization with N. meningitidis polysaccharides A and C comprised trypanolytic antibodies that recognized nonsialylated epitopes expressed on infective forms of the parasite. It is suggested that human AC vaccination could be potentially helpful as an adjuvant to a specific immunotherapy of Chagas disease, developed with native or recombinant antigens of the parasite.

Complement-mediated lysis of Trypanosoma cruzi trypomastigotes by human anti-alpha-galactosyl antibodies.

Antibodies that lyse trypomastigotes in a complement-mediated reaction are believed to be the main participants in the protection against virulent Trypanosoma cruzi. Antibodies with a specificity for alpha-galactosyl-containing determinants--generally called antiGal--were studied to determine their role in the lysis of trypomastigote forms. The titers of antiGal markedly increase in Chagas's disease. In the present study we demonstrate binding of this antibody to T. cruzi and the complement-mediated lysis of trypomastigotes by antiGal. Lysis of metacyclic trypomastigotes by whole Chagasic (Ch) serum or isolated antiGal fractions was equally inhibited by alpha- but not by beta-galactosides. Most of the lytic power of the Ch antiGal as well as of the whole Ch serum was removed by absorption on Synsorb-linked Gal alpha 1, 3Gal beta 1, 4GlcNAc followed by rabbit erythrocyte absorption. The Ch antiGal had a lower affinity for melibiose bound to agarose than for the trisaccharide linked to Synsorb, and was several times more effective in the immunolysis of trypomastigotes than the corresponding antiGal from normal human serum. Lytic antibodies were partly absorbed by Serratia marcescens but not by Escherichia coli O111. A human volunteer immunized with an S. marcescens vaccine elicited a specific antiGal response that was lytic to trypomastigotes (70% lysis). We suggest that in vivo high-affinity antiGal antibody clones, as occur in Ch patients, may significantly contribute to the destruction of the parasite, whereas low-affinity antiGal clones are much less effective in the protection against T. cruzi infection.

Isolation and characterization of the localized adherence factor of enteropathogenic Escherichia coli.

The binding factor of enteropathogenic Escherichia coli O111:H- responsible for localized adherence (LA) on HeLa cells was investigated. Inhibition of LA by carbohydrates and lectins showed that the reactive epitope on HeLa cells contains N-acetylgalactosamine units. Treatment of bacteria with EDTA for extraction of lipopolysaccharides eliminated these polymers as binding factors. Such treatment also caused a marked increase in adhesion suggesting steric hindrance by lipopolysaccharides of the LA factor binding capacity. Immunoblotting with rabbit antibodies showed a strong reaction with two components with approximate molecular sizes of 29 and 32 kilodaltons (kDa) present in the outer membrane preparations of bacteria. Both the absorbed rabbit immune serum and the outer membrane preparation of the bacteria inhibited bacterial adhesion by 100%. Outer membrane components were isolated from an N-acetylgalactosamine-agarose column by elution with KSCN, labeled with 125I, and immunoprecipitated with absorbed rabbit hyperimmune antiserum. The only component precipitated was the protein doublet at 29 to 32 kDa corresponding to the components detected by immunoblotting. The predominant component was always the 32-kDa polypeptide. We conclude that this component of the outer membrane is the best candidate for the LA factor in enteropathogenic E. coli.

Anti-alpha-galactosyl antibodies in chagasic patients. Possible biological significance.

1. Antibodies from Chagasic patients (Ch), bound to a column of immobilized purified glycoprotein 25-kDa antigen of Trypanosoma cruzi epimastigotes (gp25), were partially lytic (70% lysis at 50 micrograms/ml) to cultured metacyclic trypomastigotes (Y strain) in a complement-mediated reaction (alternative pathway). 2. Antibodies (Ch) eluted with galactose from a melibiose-Agarose column reacted in ELISA titration plates with gp25, whole cells of metacyclic trypomastigotes (Y strain), and less intensely with aqueous extracts of either T. cruzi (CL-14 strain) or Herpetomonas muscarum. 3. Agglutination of rabbit erythrocytes by anti-Gal antibodies from Chagasic patients or normal human sera (NHS) was inhibited by galactose and alpha-but not beta-anomeric galactosides. 4. Anti-Gal antibodies (Ch or NHS) were lytic to metacyclic trypomastigotes in complement-mediated reactions. 5. Agglutination of rabbit red cells by a serum sample from a T. cruzi-infected Rhesus monkey was inhibited by laminin. This serum was also lytic to metacyclic forms of T. cruzi (Y strain) involving the alternative complement pathway (70% lysis at 1:20 final dilution). 6. These results open the possibility of using anti-Gal antibodies for protection against infection by virulent T. cruzi.

Anti-galactosyl antibodies in chagasic patients: possible biological significance

Antibodies from Chagasic patients (Ch), bound to a column of immobilized purified glycoprotein 25-kDa antigen of Trypanosoma cruzi epimastigotes (gp25), were partially lytic (70% lysis at 50 microng/ml) to cultured metacyclic trypomastigotes (Y strain) in a complement-mediated reaction (alternative pathway). Antibodies (Ch) eluted with galactose from a melibiose-Agarose column reacted in ELISA titration plates with gp25, whole cells of metacyclic trypomastigotes (Y strain), and less intensely with aqueous extracts of either T. cruzi (CL- 14 strain) or Herpetomonas muscarum. Agglutination of rabbit erythrocytes by anti-Gal antibodies from Chagasic patients or normal human sera (NHS) was inhibited by galactose and alfa- but not ß- anomeric galactosides. Anti-Gal antibodies (Ch or NHS) were lytic to metacyclic trypomastigotes in complement-mediated reactions. Agglutination of rabbit red cells by a serum sample from a T. cruzi-infected Rhesus monkey was inhibited by laminin. This serum was also lytic to metacyclic forms of T. cruzi (Y strain) involving the alternative complement pathway (70% lysis at 1:20 final dilution). These results open the possibility of using anti-Gal antibodies for protection against infection by virulent T. cruzi