973 resultados para Células B


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O acidente vascular cerebral isquêmico (AVCi) causa danos celulares por provocar intensa excitotoxicidade e estresse oxidativo após privação de oxigênio e glicose para uma região do encéfalo. Neste trabalho, investigamos o potencial neuroprotetor da planta amazônica Brosimum acutifolium que é rica em flavanas como a 4',7-diidroxi-8-(3,3-dimetilalil)flavana (brosimina b, aqui abreviada como Bb) que apresenta elevado potencial antioxidante. Utilizamos cultura de células retinianas de embrião de galinha submetidas a hipóxia experimental, por privação de oxigênio e glicose, para avaliarmos o potencial antioxidante da Bb através da análise do sequestro do radical 2,2-difenil-1-picril-hidrazil (DPPH). Além disso, avaliamos a viabilidade celular (VC) e o perfil oxidativo e antioxidativo após 3, 6 e 24 horas de hipóxia, pela produção de oxigênio reativo (Ob>2b>-) e atividade antioxidante endógena pela enzima catalase, respectivamente. Nossos resultados demonstram que nosso modelo experimental de hipóxia in vitro provoca redução tempo-dependente da VC, acompanhada por intenso estrese oxidativo, devido à excessiva produção de oxigênio reativo (Ob>2b>-). O tratamento com Bb (10μM) protegeu significativamente a viabilidade celular durante 3 e 6 h de hipóxia experimental em células retiniana cultivadas in vitro, além de favorecer o aumento da atividade da enzima catalase em todos os tempos testados. Desta forma, concluímos que a Bb possui ação antioxidante e neuroprotetor por contribuir na defesa contra o estresse oxidativo induzido em condições de hipóxia, tornando-se como uma droga com potencial uso em tratamentos em casos de AVCi in vivo.

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Pós-graduação em Pesquisa e Desenvolvimento (Biotecnologia Médica) - FMB

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Pós-graduação em Ciências Biológicas (Genética) - IBB

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Pós-graduação em Pesquisa e Desenvolvimento (Biotecnologia Médica) - FMB

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The oral cancer model in hamsters shows many simílarities with developmental oral cancer in humans. The proliferating capacity is one the most characteristics of neoplásica ce/Is and detection of these ce/Is allow us, throughout of its counting, to achieve an estimated tumour growing index, with a consequent repercussion about prognostic and in the treatment of those lesions. 40 golden Syrian hamsters, both genders, aged between two to six mouth and weight 150g in average were used. The left síde of tangue of each animal was painted for eight consecutive weeks, with a solution of DMBA. Tongues were removed, fixed in 10% buffered fonnal solution. The histological slides were stained by AgNOR technique and by PCNA and β-catenin immunohistochemical antibodies. Statistical analyzes were performed by ANOVA one-way test and Tukey test. We may conclude that an association between AgNOR and PCNA might indicate the higher proliferating activity of the analyzed celIs. The experimental carcinogenesis model in hamster tongue is an available methodology for immunohistochemistry study. And finally, PCNA and β-catenin immunohistochemical antibodies may be used to analyze possible premalignant areas in oral leukoplakia

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A Anfotericina B é o fármaco antifúngico referência desde a sua descoberta na década de 50 até os dias atuais para o tratamento de infecções fúngicas sistêmicas. O objetivo do trabalho é realizar uma revisão bibliográfica que forneça os sistemas de liberação comercializados e os que estão em estudo, focando estratégias tecnológicas que possam servir para resolver os problemas da baixa solubilidade em água e da alta nefrotoxicidade da Anfotericina B. A AmB é um fármaco que apresenta inexpressiva solubilidade em meio-aquoso, principalmente na região de pH dos fluídos biológicos (7,4–8,0), sendo administrado atualmente por via endovenosa. Justificando a importância desse estudo para a área farmacêutica, novos sistemas de liberação que usem a via oral, aumentarão a adesão por crianças e idosos, além de aumentar o arsenal terapêutico e diminuir os gastos com hospitalizações. Por ter a sua utilidade clínica limitada em razão de sua alta toxicidade, tem-se buscado direcionar a AmB especificamente para o fungo ou pelo menos para o local da infecção, mantendo-se longe o fármaco das células hospedeiras. Para isso, se busca diferentes veículos que não o desoxicolato (Fungizone). Por fim, as formulações lipídicas mostram-se com maior eficácia e com menor toxicidade comparadas a Anfotericina B-desoxicolato, mas não fazem parte da rotina hospitalar em razão do seu alto custo

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The Kaposi-associated Herpesvirus (KSHV) also known as Human Herpesvirus 8 (HHV-8) is associated with the development of Kaposi’s sarcoma (KS) and others limphoprolipheratives diseases such as Primary Effusion Lymphoma (PEL) and Multicentric Castleman Disease (MCD). Even though the virus is considered lymphotropic, it is able to infect others cell types such as macrophages, dendritic cells, endothelial cells, monocytes and fibroblasts. After infection, KSHV be latent expressing essential viral genes to its maintenance in a infected cell. However, in some circumstances may occur the reactivation of lytic cycle producing new viral particles. K1 protein of KSHV interferes in the cellular signaling inducing proliferation and supporting cellular transformation. K1 is encoded by viral ORF-K1, which shows high variability between different genotypes of KSHV. So far, it is not clear whether different isoforms of K1 have specific immunobiological features. The KSHV latency is maintained under strict control by the immune system supported by an adequate antigen presentation involving Human Leucocyte Antigen (HLA) class I and II. Polymorphisms of HLA class I and II genes confer an enormous variability in molecules that recognize a large amount of antigens, but also can increase the susceptibility to autoimmune diseases. Therefore, the present study aims to genotype HLA class I (A and B) and class II (DR and DQ) from volunteers to identify haplotypes that can provide better response to K1 epitopes of different KSHV genotypes. First of all, 20 volunteers were selected to genotype HLA genes. In our results we observed prevalence of certain HLA class I haplotypes as HLAA1, HLA-A2, HLA-A24, HLA-A26, HLA-B8, HLA-B18 e HLA-B44. After the in silico analysis using BIMAS and SYFPEITHI databases, we observed high scores for epitopes from the B genotype of KSHV, indicating...(Complete abstract click electronic access below)

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This paper proposed a two-dimensional spatial model to describe the adaptive immune response for viral hepatitis B. This model considered six populations: healthy hepatocytes T, infected hepatocytes Y , hepatitis B virus V , innate immune system I, active immune system X and memory cells, X. First, a compartmental model was constructed and its equilibrium solutions and also the threshold values related to the stability of each solution were obtained. Using this model, we was able to reproduce the different trends observed for the disease, which are: individuals that eliminate the infection without forming immune response, patients with acute and chronic carriers. By including dispersion of defense cells of the immune system and virus (spatial model), we analyze two situations: homogeneous model, in which the model parameters are the same at all points of the network, and heterogeneous model, which characterizes cells more permeable and less permeable to virus invasion. For the two spatial models (homogeneous and heterogeneous) the times relatead to the viral erradication and/or virus invasion and persistence becoming smaller in relation to the compartmental model. The results also showed that for the set of values used in the simulations and if the two diffusion rates are different from zero, the model is sensitive to variations in the rate of viral spread and not dependent on the dispersion of memory cells. Finally, the heterogeneous model when compared to the homogeneous model shows that the infection can be spatially limited depending on the type of the cell involved in the infection process

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Bacillus thuringiensis (Bt), is an environmental Gram-positive spore-forming bacterium that produces crystalline parasporal protein (Cry) during sporulation. The inclusions often exhibit strong and specific insecticidal activity, making Bt an agent for agricultural controlling insects pest, mites, protozoa and nematodes. Recent studies reported that some of these Crys do not show cytotoxicity against insects but they are capable to kill some human and animal cancer cells. These proteins were denominated parasporins (PS). However, antitumor activity of Bt parasporin on the development of murine colorectal cancer (CT-26), are not well studies and these are no reports on the in vivo effect of these proteins. Thus, the present study evaluated the in vitro and in vivo anti-tumoral activity of Bt parasporin against the murine colorectal cancer line CT-26. Therefore, Balb/c mice were s.c. inoculated with CT-26 cells and weekly treated with parasporin (i.p.) pre-activated by enzymatic digestion with trypsin or proteinase K. Our results have shown, for the first time, that despite the anti-tumor activity in vitro, parasporin crystals couldn’t combat tumor growth in vivo. Instead, this protein was highly toxic, affecting the liver and spleen, with possible effect on other organs, decreasing the survival of treated animals. The results indicate the need for studies to better detoxification or manipulation of parasporin for therapeutic use and new studies for analysis of toxicological effects of repetitive exposure of farmers to this toxin