OBJECTIVES: To assess the distribution of dementia subtypes in Brazil using a population-based clinicopathological study. METHOD: Brains from deceased individuals aged ≥50 years old were collected after the next of kin signed an informed consent form and provided information through standardized questionnaires. Post-mortem clinical diagnoses were established in consensus meetings, and only cases with moderate or severe dementia or without cognitive impairment were included in the analysis. Immunohistochemical neuropathological examinations were performed following the universally accepted guidelines. A diagnosis of Alzheimer's disease was made when there were at least both a moderate density of neuritic plaques (Consortium to Establish a Register for Alzheimer's disease B or C) and Braak stage III for neurofibrillary tangle distribution. For the diagnosis of vascular dementia, at least three zones or strategic areas had to be affected by infarcts, lacunae, or microinfarcts. RESULTS: From 1,291 subjects, 113 cases were classified as having moderate or severe dementia, and 972 cases were free of cognitive impairment. The neuropathological diagnoses of the dementia sub-group were Alzheimer's disease (35.4%), vascular dementia (21.2%), Alzheimer's disease plus vascular dementia (13.3%), and other causes of dementia (30.1%). Small-vessel disease, which alone was not considered sufficient for a vascular dementia diagnosis, was present in 38.9% of all of the dementia cases and in 16.8% of the group without cognitive impairment (odds ratio = 2.91; 95% confidence interval, 1.53-5.51), adjusted for age, sex, and education. CONCLUSIONS: The relatively high frequencies of vascular dementia and small-vessel disease in the dementia sub-group constitute relevant findings for public health initiatives because control of vascular risk factors could decrease the prevalence of dementia in developing countries.

RNAs não codificadores (ncRNAs) têm sido recentemente objeto de atenção muito maior devido aos avanços técnicos no sequenciamento que expandiram a caracterização dos transcritomas em diferentes organismos. ncRNAs possuem diferentes comprimentos (22 nt a >1.000 nt) e mecanismos de ação que essencialmente compreendem uma sofisticada rede de regulação de expressão gênica. A publicação recente dos genomas e transcritomas dos esquistossomos aumentou a descrição e caracterização de um grande número de genes do parasita. Aqui nós revisamos o número de genes preditos e a cobertura das bases do genoma em face dos ESTs públicos disponíveis, incluindo uma avaliação crítica da evidência e caracterização de ncRNAs em esquistossomos. Nós mostramos dados de expressão de ncRNAs em Schistosoma mansoni. Nós analisamos três conjuntos diferentes de dados de experimentos com microarranjos: (1) medidas de expressão em larga escala de vermes adultos; (2) genes diferencialmente expressos de S. mansoni regulados por uma citocina humana (TNF-α) no parasita em cultura; e (3) expressão estágio-especifica de ncRNAs. Todos estes dados apontam para ncRNAs envolvidos em diferentes processos biológicos e respostas fisiológicas que sugerem funcionalidade destes novos personagens na biologia do parasita. Explorar este mundo é um desafio para os cientistas sob uma nova perspectiva molecular da interação parasita-hospedeiro e do desenvolvimento do parasita.

Non-coding RNAs (ncRNAs) were recently given much higher attention due to technical advances in sequencing which expanded the characterization of transcriptomes in different organisms. ncRNAs have different lengths (22 nt to >1, 000 nt) and mechanisms of action that essentially comprise a sophisticated gene expression regulation network. Recent publication of schistosome genomes and transcriptomes has increased the description and characterization of a large number of parasite genes. Here we review the number of predicted genes and the coverage of genomic bases in face of the public ESTs dataset available, including a critical appraisal of the evidence and characterization of ncRNAs in schistosomes. We show expression data for ncRNAs in Schistosoma mansoni. We analyze three different microarray experiment datasets: (1) adult worms' large-scale expression measurements; (2) differentially expressed S. mansoni genes regulated by a human cytokine (TNF-α) in a parasite culture; and (3) a stage-specific expression of ncRNAs. All these data point to ncRNAs involved in different biological processes and physiological responses that suggest functionality of these new players in the parasite's biology. Exploring this world is a challenge for the scientists under a new molecular perspective of host-parasite interactions and parasite development.

Resumo Os modelos de estadiamento neuropatológico da doença de Alzheimer (DA) têm sido desenvolvidos nos últimos 20 anos. Entretanto, têm sido quase exclusivamente testados em caucasianos de ascendência norte-européia ou em asiáticos. Objetivos: verificar quais dos critérios neuropatológicos discrimina melhor entre a DA e o envelhecimento normal em uma casuística clinicopatológica brasileira bem caracterizada. Métodos: uma amostra aleatória de 89 casos do Banco Brasileiro de Encéfalos do Estudo de Envelhecimento Cerebral foi submetida à avaliação neuropatológica completa com imunohistoquímica. As condições clínicas e funcionais foram avaliadas mediante entrevista com informante confiável. Os escores na Clinical Dementia Rating Scale (CDR) foram comparados com os escores dos estágios de Braak e Braak, do CERAD (Consortium to Establish a Registry for Alzheimer's Disease) e do consórcio NIA-Reagan (National Institute of Aging-Reagan Institute). Casos com diagnósticos neuropatológicos diferentes de DA foram excluídos (n=27). Resultados: Os 62 casos foram classificados em: CDR0=39, CDR0,5=9, CDR³1=14. Não havia diferenças quanto a idade, gênero e escolaridade entre os grupos. Os escores no CERAD correlacionaram-se melhor com os do CDR (r=0,5303; p<0,001). Os escores nos estágios de Braak e Braak foram significativamente mais elevados nos casos com CDR mais altos. A correlação do CDR com os escores dos critérios NIA-Reagan foi parcialmente rompida porque grande proporção de casos não se enquadrava em nenhuma das categorias diagnósticas destes critérios. Conclusões: Nesta casuística, os critérios do CERAD correlacionam-se melhor com os do CDR. Como observado por outros estudos, alguns casos de indivíduos cognitivamente normais, preencheram critérios neuropatológicos para o diagnóstico de DA.

Abstract The current neuropathological staging models of Alzheimer's disease (AD) have been developed within the last 20 years. Nevertheless, they were mostly tested on Caucasians of Northern European ancestry or on Asians. Objective: To verify which of the accepted neuropathologic criteria best discriminates AD from normal aging in a well characterized Brazilian clinicopathological series. Methods: A random sample consisting of 89 subjects belonging to the Brazilian Brain Bank of the Aging Brain Study were clinically and neuropathologically fully assessed using immunohistochemistry. Clinical and functional statuses were assessed by interviewing a reliable informant. The Clinical dementia rating scale (CDR) was compared to Braak and Braak stage, the consortium to establish a registry for Alzheimer's disease (CERAD) score and NIA-Reagan (National Institute of Aging - Reagan Institute) score. Subjects with a neuropathologic diagnosis other then AD were excluded (n=27). Results: The CDR score distribution for the 62 selected subjects was as follows: CDR0=39, CDR0.5=9, CDR³1=14. There were no differences regarding age, gender and education among the groups. CDR score correlated best with the CERAD score (r=0.5303; p<0.001) . Braak and Braak stage was significantly higher in subjects with higher CDR. Correlation of the NIA-Reagan criteria was partially disrupted because a large proportion of subjects did not fit any of its categories. Conclusions: In this series, CERAD criteria better correlated with the CDR groups. Consistent with earlier studies, some cognitively normal subjects have AD neuropathological diagnosis.