24 research outputs found
Expression Profiling of Major Histocompatibility and Natural Killer Complex Genes Reveals Candidates for Controlling Risk of Graft versus Host Disease
Background: The major histocompatibility complex (MHC) is the most important genomic region that contributes to the risk of graft versus host disease (GVHD) after haematopoietic stem cell transplantation. Matching of MHC class I and II genes is essential for the success of transplantation. However, the MHC contains additional genes that also contribute to the risk of developing acute GVHD. It is difficult to identify these genes by genetic association studies alone due to linkage disequilibrium in this region. Therefore, we aimed to identify MHC genes and other genes involved in the pathophysiology of GVHD by mRNA expression profiling. Methodology/Principal Findings: To reduce the complexity of the task, we used genetically well-defined rat inbred strains and a rat skin explant assay, an in-vitro-model of the graft versus host reaction (GVHR), to analyze the expression of MHC, natural killer complex (NKC), and other genes in cutaneous GVHR. We observed a statistically significant and strong up or down regulation of 11 MHC, 6 NKC, and 168 genes encoded in other genomic regions, i.e. 4.9%, 14.0%, and 2.6% of the tested genes respectively. The regulation of 7 selected MHC and 3 NKC genes was confirmed by quantitative real-time PCR and in independent skin explant assays. In addition, similar regulations of most of the selected genes were observed in GVHD-affected skin lesions of transplanted rats and in human skin explant assays. Conclusions/Significance: We identified rat and human MHC and NKC genes that are regulated during GVHR in skin explant assays and could therefore serve as biomarkers for GVHD. Several of the respective human genes, including HLA-DMB, C2, AIF1, SPR1, UBD, and OLR1, are polymorphic. These candidates may therefore contribute to the genetic risk of GVHD in patients
Avaliação de rugosidade, dureza e superfĂcie dos cimentos de ionĂ´mero de vidro apĂłs diferentes sistemas de acabamento e polimento
Resumo Introdução A rugosidade de superfĂcie Ă© uma limitação que interfere nos desempenhos mecânico e estĂ©tico do cimento de ionĂ´mero de vidro (CIV), sendo necessária a utilização de procedimentos para acabamento e polimento adequados Ă s propriedades desse material. Objetivo Avaliar o efeito de diferentes sistemas de acabamento e polimento na rugosidade, dureza e superfĂcie de restaurações realizadas com dois tipos de CIV. Material e mĂ©todo Foram utilizados 100 corpos de prova (CP), divididos em 10 grupos, de acordo com o tipo de CIV (convencional e modificado por resina) e o sistema de acabamento e polimento empregado [C-tira de poliĂ©ster (controle); PD-ponta diamantada; DA-discos abrasivos; PE-ponta Enhance; BM-broca multilaminada]. ApĂłs sete dias em água destilada, os CP foram avaliados em MicroscĂłpio EletrĂ´nico de Varredura (MEV) e submetidos aos testes de rugosidade de superfĂcie e microdureza Vickers. A análise estatĂstica foi realizada com ANOVA dois fatores e pĂłs-Teste de Tukey. Resultado A análise por MEV indicou superfĂcie mais lisa no grupo BM em ambos os tipos de CIV. Quanto Ă rugosidade, observou-se diferença estatisticamente significante (p<0,05) entre grupos do CIV convencional, mas nĂŁo houve diferença entre os tipos de CIV. Com relação Ă dureza, o CIV convencional apresentou melhores resultados que o modificado por resina. No fator materiais de acabamento e polimento, nĂŁo se verificou diferença estatisticamente significativa, independentemente do tipo de CIV. ConclusĂŁo os grupos BM apresentaram melhores resultados ao MEV; o tipo de CIV nĂŁo influenciou os valores de rugosidade; o tipo de polimento nĂŁo influenciou a dureza
Evaluation of radioinduced damage and repair capacity in blood lymphocytes of breast cancer patients
Genetic damage caused by ionizing radiation and repair capacity of blood lymphocytes from 3 breast cancer patients and 3 healthy donors were investigated using the comet assay. The comets were analyzed by two parameters: comet tail length and visual classification. Blood samples from the donors were irradiated in vitro with a 60Co source at a dose rate of 0.722 Gy/min, with a dose range of 0.2 to 4.0 Gy and analyzed immediately after the procedure and 3 and 24 h later. The basal level of damage and the radioinduced damage were higher in lymphocytes from breast cancer patients than in lymphocytes from healthy donors. The radioinduced damage showed that the two groups had a similar response when analyzed immediately after the irradiations. Therefore, while the healthy donors presented a considerable reduction of damage after 3 h, the patients had a higher residual damage even 24 h after exposure. The repair capacity of blood lymphocytes from the patients was slower than that of lymphocytes from healthy donors. The possible influence of age, disease stage and mutations in the BRCA1 and BRCA2 genes are discussed. Both parameters adopted proved to be sensitive and reproducible: the dose-response curves for DNA migration can be used not only for the analysis of cellular response but also for monitoring therapeutic interventions. Lymphocytes from the breast cancer patients presented an initial radiosensitivity similar to that of healthy subjects but a deficient repair mechanism made them more vulnerable to the genotoxic action of ionizing radiation. However, since lymphocytes from only 3 patients and 3 normal subjects were analyzed in the present paper, additional donors will be necessary for a more accurate evaluation