RESUMO
A computational challenge raised by chromosome conformation capture (3C) experiments is to reconstruct spatial distances and three-dimensional genome structures from observed contacts between genomic loci. We propose a two-step algorithm, ShRec3D, and assess its accuracy using both in silico data and human genome-wide 3C (Hi-C) data. This algorithm avoids convergence issues, accommodates sparse and noisy contact maps, and is orders of magnitude faster than existing methods.
Assuntos
Cromossomos Fúngicos , Cromossomos Humanos , Simulação por Computador , Genoma Fúngico , Genoma Humano , Imageamento Tridimensional/métodos , Leveduras/genética , Algoritmos , Humanos , Conformação de Ácido Nucleico , SoftwareRESUMO
OBJECTIVE: This paper reviews the magnetic resonance imaging (MRI) literature on the effects of prenatal alcohol exposure on the developing human brain. METHOD: A literature search was conducted through the following databases: PubMed, PsycINFO and Google Scholar. Combinations of the following search terms and keywords were used to identify relevant studies: 'alcohol', 'fetal alcohol spectrum disorders', 'fetal alcohol syndrome', 'FAS', 'FASD', 'MRI', 'DTI', 'MRS', 'neuroimaging', 'children' and 'infants'. RESULTS: A total of 64 relevant articles were identified across all modalities. Overall, studies reported smaller total brain volume as well as smaller volume of both the white and grey matter in specific cortical regions. The most consistently reported structural MRI findings were alterations in the shape and volume of the corpus callosum, as well as smaller volume in the basal ganglia and hippocampi. The most consistent finding from diffusion tensor imaging studies was lower fractional anisotropy in the corpus callosum. Proton magnetic resonance spectroscopy studies are few to date, but showed altered neurometabolic profiles in the frontal and parietal cortex, thalamus and dentate nuclei. Resting-state functional MRI studies reported reduced functional connectivity between cortical and deep grey matter structures. Discussion There is a critical gap in the literature of MRI studies in alcohol-exposed children under 5 years of age across all MRI modalities. The dynamic nature of brain maturation and appreciation of the effects of alcohol exposure on the developing trajectory of the structural and functional network argue for the prioritisation of studies that include a longitudinal approach to understanding this spectrum of effects and potential therapeutic time points.
Assuntos
Consumo de Bebidas Alcoólicas/efeitos adversos , Encéfalo/efeitos dos fármacos , Encéfalo/crescimento & desenvolvimento , Transtornos do Espectro Alcoólico Fetal/patologia , Neuroimagem/métodos , Efeitos Tardios da Exposição Pré-Natal/patologia , Adolescente , Encéfalo/embriologia , Encéfalo/patologia , Criança , Imagem de Difusão por Ressonância Magnética/métodos , Imagem de Tensor de Difusão , Feminino , Humanos , Processamento de Imagem Assistida por Computador , Lactente , Imageamento por Ressonância Magnética/métodos , Gravidez , Efeitos Tardios da Exposição Pré-Natal/etiologia , Transtornos Relacionados ao Uso de Substâncias/patologia , Transtornos Relacionados ao Uso de Substâncias/psicologiaRESUMO
Paul Roger argues that the structure for debating and endorsing new policy decisions at BVA is not fit for purpose, and that this should be reviewed and adapted so that it can meet today's demands.