Papers by fernando vargas
Genetic Testing and Molecular Biomarkers, 2015
and the Brazilian Embryonic Tumor Group** Aim: Embryonic tumors are associated with an interrupti... more and the Brazilian Embryonic Tumor Group** Aim: Embryonic tumors are associated with an interruption during normal organ development; they may be related to disturbances in the folate pathway involved in DNA synthesis, methylation, and repair. Prenatal supplementation with folic acid is associated with a decreased risk of neuroblastoma, brain tumors, retinoblastoma, and nephroblastoma. The aim of this study was to investigate the association between MTHFR rs1801133 (C677T) and RFC-1 rs1051266 (G80A) genotypes with the risk of developing nephroblastoma and neuroblastoma. Materials and Methods: Case-mother/control-mother dyad study. Samples from Brazilian children with nephroblastoma (n = 80), neuroblastoma (n = 66), healthy controls (n = 453), and their mothers (case n = 93; control n = 75) were analyzed. Genomic DNA was isolated from peripheral blood cells and/or buccal cells and genotyped to identify MTHFR C677T and RFC-1 G80A polymorphisms. Differences in genotype distribution between patients and controls were tested by multiple logistic regression analysis. Results: Risk for nephroblastoma and neuroblastoma was two-to fourfold increased among children with RFC-1 polymorphisms. An increased four-to eightfold risk for neuroblastoma and nephroblastoma was seen when the child and maternal genotypes were combined. Conclusion: Our results suggest that mother and child RFC-1 G80A genotypes play a role on the risk of neuroblastoma and nephroblastoma since this polymorphism may impair the intracellular levels of folate, through carrying fewer folate molecules to the cell interior, and thus, the intracellular concentration is not enough to maintain regular DNA synthesis and methylation pathways.
Materials Letters, 2001
Modified for crystals quantum-chemical computational approach and the periodic LUC (Large Unit Ce... more Modified for crystals quantum-chemical computational approach and the periodic LUC (Large Unit Cell) model is used for calculating structural, electronic and optical properties of F centers (two electrons trapped by an oxygen vacancy). The automated geometry optimization is carried out for the ground state of defect in both cubic and tetragonal crystalline lattices of SrTiO 3. The wave functions of two extra electrons extend over the two vacancy-closest Ti atoms and over other nearby atoms. The absorption energies are calculated using the ∆SCF scheme after the performance of system's geometry optimization. The obtained results are discussed in a comparative manner for two different crystallographic phases.
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Papers by fernando vargas