RESUMO
The m.3243A>G mutation is the most common pathogenic mutation in mitochondrial DNA. It leads to defective oxidative phosphorylation, decreased oxygen consumption and increased glucose utilization and lactate production in vitro. However, oxygen and glucose metabolism has not been studied in the brain of patients harbouring the m.3243A>G mutation. Therefore, 14 patients with the m.3243A>G mutation, not experiencing acute stroke-like episodes and 14 age-matched controls underwent positron emission tomography using 2-[(18)F]fluoro-2-deoxyglucose, [(15)O]H(2)O and [(15)O]O(2) as the tracers during normoglycaemia. The metabolic rate of oxygen and glucose were determined using a quantitative region of interest analysis. Metabolites in unaffected periventricular tissue were measured using magnetic resonance spectroscopy. We found that the cerebral metabolic rate of oxygen was decreased by 26% (range 18%-29%) in the grey as well as the white matter of patients with the m.3243A>G mutation. A decrease in the metabolic rate of glucose was found with predilection to the posterior part of the brain. No major changes were detected in cerebral blood flow or the number of white matter lesions. Our results show that the m.3243A>G mutation leads to a global decrease in oxygen consumption in the grey matter including areas where no other signs of disease were present.
Assuntos
Encefalopatias Metabólicas/genética , Encefalopatias Metabólicas/metabolismo , Metabolismo Energético/genética , Doenças Mitocondriais/genética , Doenças Mitocondriais/metabolismo , Mutação/genética , Adulto , Encéfalo/metabolismo , Encéfalo/fisiopatologia , Encefalopatias Metabólicas/diagnóstico por imagem , Córtex Cerebral/metabolismo , Córtex Cerebral/fisiopatologia , Análise Mutacional de DNA , Feminino , Predisposição Genética para Doença/genética , Testes Genéticos , Glucose/metabolismo , Humanos , Hipóxia Encefálica/diagnóstico por imagem , Hipóxia Encefálica/genética , Hipóxia Encefálica/metabolismo , Espectroscopia de Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Doenças Mitocondriais/diagnóstico por imagem , Proteínas Mitocondriais/genética , Consumo de Oxigênio/genética , Tomografia por Emissão de PósitronsRESUMO
The formation of vortices by topological phase engineering has been realized experimentally to create the first two- and four-quantum vortices in dilute atomic Bose-Einstein condensates. We consider a similar system, but in addition to the Ioffe-Pritchard magnetic trap we employ an additional hexapole field. By controlling cyclically the strengths of these magnetic fields, we show that a fixed amount of vorticity can be added to the condensate in each cycle. In an adiabatic operation of this vortex pump, the appearance of vortices into the condensate is interpreted as the accumulation of a local Berry phase. Our design can be used as an experimentally realizable vortex source for possible vortex-based applications of dilute Bose-Einstein condensates.
