Sleep is beneficial to learning, but the underlying mechanisms remain controversial. The synaptic homeostasis hypothesis (SHY) proposes that the cognitive function of sleep is related to a generalized rescaling of synaptic weights to intermediate levels, due to a passive downregulation of plasticity mechanisms. A competing hypothesis proposes that the active upscaling and downscaling of synaptic weights during sleep embosses memories in circuits respectively activated or deactivated during prior waking experience, leading to memory changes beyond rescaling.
View Article and Find Full Text PDFIn this study, we investigated the associations between single-nucleotide polymorphisms in GAB2 (rs2373115), GSK3B (rs6438552) and SORL1 (rs641120) and Alzheimer's disease (AD), both alone and in combination with the APOE*4 allele.
View Article and Find Full Text PDFElectroconvulsive therapy (ECT) is a well-established psychiatric treatment for severe depression. Despite its clinical utility, post-ECT memory deficits are a common side effect. Neuronal plasticity and memory consolidation are intimately related to the expression of immediate early genes (IEG), such as Egr1, Fos and Arc.
View Article and Find Full Text PDFObjective: Epidermal growth factor receptor is involved in the pathogenesis of non-small cell lung cancer and has recently emerged as an important target for molecular therapeutics. The KRAS oncogene also plays an important role in the development of lung cancer. The aim of this study was to evaluate the frequency of epidermal growth factor receptor and KRAS mutations in a population of Brazilian patients with non-small cell lung cancer.
View Article and Find Full Text PDFThe frequency distribution of SNPs and haplotypes in the ABCB1, SLCO1B1 and SLCO1B3 genes varies largely among continental populations. This variation can lead to biases in pharmacogenetic studies conducted in admixed populations such as those from Brazil and other Latin American countries. The aim of this study was to evaluate the influence of self-reported colour, geographical origin and genomic ancestry on distributions of the ABCB1, SLCO1B1 and SLCO1B3 polymorphisms and derived haplotypes in admixed Brazilian populations.
View Article and Find Full Text PDFAim: Polymorphisms in the CYP3A5 and ABCB1 genes have been investigated as modulators of the pharmacokinetics and clinical effects of cyclosporine (CSA) and tacrolimus (TAC) in European, North American and Asian populations, with controversial results. The extensive variation in worldwide frequency distribution of CYP3A5 and ABCB1 polymorphisms is a caveat against the extrapolation of these data to the heterogeneous and admixed Brazilian population. We investigated the effect of CYP3A5 and ABCB1 polymorphisms on CSA and TAC dose-adjusted trough concentration (C₀/dose) in Brazilian renal transplant recipients, during the first 3 months post-transplantation.
View Article and Find Full Text PDFBased on pre-DNA racial/color methodology, clinical and pharmacological trials have traditionally considered the different geographical regions of Brazil as being very heterogeneous. We wished to ascertain how such diversity of regional color categories correlated with ancestry. Using a panel of 40 validated ancestry-informative insertion-deletion DNA polymorphisms we estimated individually the European, African and Amerindian ancestry components of 934 self-categorized White, Brown or Black Brazilians from the four most populous regions of the Country.
View Article and Find Full Text PDFThere is a considerable interindividual variation in L-thyroxine [3,5,3',5'-tetraiodo-l-thyronine (T4)] dose required for thyrotropin (thyroid-stimulating hormone) suppression in patients with differentiated thyroid cancer. To investigate whether uridine diphosphate-glucuronosyl transferase 1A1 (UGT1A1)-mediated T4 glucuronidation in liver affects T4 dose, we genotyped 101 patients for the common UGT1A1-53(TA)n polymorphism and compared T4 doses among patients having zero (5/6 and 6/6 genotypes), one (6/7 genotype), or two (7/7 and 7/8 genotypes) copies of the low-expression (TA)7 and (TA)8 alleles. A significant trend for decreasing T4 dose with increasing number of copies of (TA)7 and (TA)8 (P=0.
View Article and Find Full Text PDFThe activation of inflammatory cascades has been consistently demonstrated in the pathophysiology of Alzheimer's disease (AD). Among several putative neuroinflammatory mechanisms, the tumor necrosis factor α (TNF-α) signaling system has a central role in this process. Recent evidence indicates that the abnormal production of inflammatory factors may accompany the progression from mild cognitive impairment (MCI) to dementia.
View Article and Find Full Text PDFAims: The heterogeneity of the Brazilian population renders the extrapolation of pharmacogenomic data derived from well-defined ethnic groups inappropriate. We investigated the influence of self-reported 'race/color', geographical origin and genetic ancestry on the distribution of four VKORC1 SNPs and haplotypes in Brazilians. Comparative data were obtained from two major ancestral roots of Brazilians: Portuguese and Africans from former Portuguese colonies.
View Article and Find Full Text PDFObjective: The 21-gene expression assay may support the decision regarding use of chemotherapy in early breast cancer. We sought to investigate the potential impact of incorporating the 21-gene expression assay into private practice in Brazil, from the perspective of third party payers.
Methods: We conducted a web-based survey with 30 (of a total of approximately 700) Brazilian medical oncologists, who were stratified by State according to the proportion of patients with breast cancer and private health insurance.
Objectives: Abnormalities in neurotrophic systems have been reported in Alzheimer's disease (AD), as shown by decreased serum brain-derived neurotrophic factor (BDNF) levels and association with BDNF genetic polymorphisms. In this study, we investigate whether these findings can be detected in patients with mild cognitive impairment (MCI), which is recognized as a high risk condition for AD. We also address the impact of these variables on the progression of cognitive deficits within the MCI-AD continuum.
View Article and Find Full Text PDFObjective: To identify predictors of the progression from pre-dementia stages of cognitive impairment in Alzheimer's disease is relevant to clinical management and to substantiate the decision of prescribing antidementia drugs.
Method: Longitudinal study of a cohort of elderly adults with amnestic mild cognitive impairment and healthy controls, carried out to estimate the risk and characterize predictors of the progression to Alzheimer's disease.
Results: Patients with amnestic mild cognitive impairment had a higher risk to develop Alzheimer's disease during follow-up (odds ratio = 4.
Apolipoprotein E (APOE) has been extensively studied as a risk factor for sporadic and late onset Alzheimer's Disease (AD). APOE allele (∗)3, the most frequent variant, is not associated to cognitive dysfunction (CD) or to increased AD risk. Differently, the (∗)4 allele is a well-established risk factor for CD, while the (∗)2 allele is associated with survival and longevity.
View Article and Find Full Text PDFSclerosing extramedullary hematopoietic tumor has been described as a rare manifestation of chronic myeloproliferative neoplasm. The lack of knowledge about this entity has caused it to be mistaken for many types of nonhematopoietic and hematopoietic tumors. We present the case of a 71-year-old lady with a long history of primary myelofibrosis, which developed multiple abdominal sclerosing extramedullary hematopoietic tumors with good clinical evolution.
View Article and Find Full Text PDFBackground/aims: Abnormal inflammatory response has been associated to the pathogenesis of Alzheimer's disease (AD) and may be a marker of an ongoing neurodegenerative process. The aim of this study was to evaluate the serum levels of interleukin-1beta (IL-1beta) in patients with mild cognitive impairment (MCI) and AD.
Methods: One hundred and sixty-three older adults (58 with mild to moderate AD, 74 with MCI and 31 healthy controls) were recruited for this study.
The aim of the present study was to evaluate the clinicopathological, immunohistochemical, and molecular genetic features of gastrointestinal stromal tumors in Brazil and compare them with cases from other countries. Five hundred and thirteen cases were retrospectively analyzed. HE-stained sections and clinical information were reviewed and the immunohistochemical expression of CD117, CD34, smooth-muscle actin, S-100 protein, desmin, CD44v3 adhesion molecule, p53 protein, epidermal growth factor receptor, and Ki-67 antigen was studied using tissue microarrays.
View Article and Find Full Text PDFThe Nogo gene maps to 2p14-p13, a region consistently associated with schizophrenia and bipolar disorder. The association of a polymorphism in Nogo was previously investigated by two groups, with divergent results. In this report, using an alternative approach, we evaluated this same polymorphism in 725 individuals, including patients with schizophrenia, bipolar disorder, normal controls and non-human primate samples.
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