Recombinant vaccines and the development of new vaccine strategies

Vaccines were initially developed on an empirical basis, relying mostly on attenuation or inactivation of pathogens. Advances in immunology, molecular biology, biochemistry, genomics, and proteomics have added new perspectives to the vaccinology field. The use of recombinant proteins allows the targeting of immune responses focused against few protective antigens. There are a variety of expression systems with different advantages, allowing the production of large quantities of proteins depending on the required characteristics. Live recombinant bacteria or viral vectors effectively stimulate the immune system as in natural infections and have intrinsic adjuvant properties. DNA vaccines, which consist of non-replicating plasmids, can induce strong long-term cellular immune responses. Prime-boost strategies combine different antigen delivery systems to broaden the immune response. In general, all of these strategies have shown advantages and disadvantages, and their use will depend on the knowledge of the mechanisms of infection of the target pathogen and of the immune response required for protection. In this review, we discuss some of the major breakthroughs that have been achieved using recombinant vaccine technologies, as well as new approaches and strategies for vaccine development, including potential shortcomings and risks.

Enzymatic activation of the carcinogens 2 phenylethylhydrazine and 1,2 dimethylhydrazine to carbon centered radicals

Spin-trapping experiments demonstrate that oxidation of 1,2-dimethylhydrazine and 2-phenylethylgydrazine generates a comparable yield of carbon-centered radicals when catalyzed by horseradish peroxidase-H2O2. Using oxyhemoglobin as the catalyst, 2-phenylethylgydrazine oxidation generates ten times carbon-centered radicals than 1,2-dimethylhidrazine oxidation. This results is in agreement with oxygen consumption studies from which the apparent KM values of 8.0 mM and 72 mM were calculated for the oxyhemoglobin-catalyzed oxidation of 2-phenylethylhydrazine and 1,2-dimethylhydrazine, respectively. These differences in metabolic activation of mono- and disubstituted hydrazines may be of importance regarding the carcinogenic properties of these derivatives

Prevalencia de infeccao chagasica em necropsias no Triangulo Mineiro. / Prevalence of Chagas' infection in necropsies in the Triangulo Mineiro

Analisou-se a prevalencia da infeccao chagasica em 2690 necropsias realizadas no Triangulo Mineiro. Os resultados indicaram que 38,84% dos necropsiados eram chagasicos e que nao houve declinio da infeccao nos ultimos anos. Discutiu-se tais resultados, comparando-os com os de outros Autores que analisaram a questao

Sirenomelia. / Sirenomelia

Relata-se um caso de sirenomelia em crianca do sexo masculino que alem da fusao dos membros inferiores, apresentava displasia dos rins, agenesia vesicoureteral e da genitalia externa, atresia anorretal com anus imperfurado, anomalias dos ossos pelvicos e do segmento sacrococcigeo da coluna, facies de Potter, diverticulo de Meckel e arteria umbilical unica.Confrontam-se tais alteracoes com as referidas na literatura. Descrevem-se os dados etiopatogeneticos mais atuais sobre este raro conjunto de malformacoes, relacionando-o sindrome de regressao caudal