RESUMO
There have been only few studies of brain magnetic resonance imaging (MRI) in spinocerebellar ataxia (SCA) type 2. We investigated 20 SCA2 patients, from 11 Sicilian families, and 20 age-matched control subjects using MRI. Our data confirm that olivopontocerebellar atrophy (OPCA) is the typical pattern in SCA2. We found no significant correlation between infratentorial atrophy, disease duration, or the number of CAG repeats in our SCA2 patients, but there was supratentorial atrophy in 12 patients, with a significant correlation between supratentorial atrophy and disease duration. OPCA appears to represent the "core" of the SCA2: however, central nervous system involvement is not limited to pontocerebellar structures. We therefore consider central nervous system degeneration in SCA2 as a widespread atrophy. MRI is helpful in diagnosing SCA, but it is not diagnostic in the absence of clinical and molecular studies. We suggest that serial MRI may play a role in evaluating "in vivo" the progressive steps of neurodegeneration in SCA2, for a better comprehension of the pathophysiology of this disorder.
Assuntos
Cerebelo/patologia , Imageamento por Ressonância Magnética , Degenerações Espinocerebelares/diagnóstico , Degenerações Espinocerebelares/patologia , Adulto , Idoso , Atrofia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Atrofias Olivopontocerebelares/diagnóstico , Atrofias Olivopontocerebelares/etiologia , Sequências Repetitivas de Ácido Nucleico , Degenerações Espinocerebelares/complicações , Degenerações Espinocerebelares/genética , Fatores de TempoRESUMO
CO(2) gas exchange, ribulose-1,5-bisphosphate, and electron transport have been measured in leaves of a yellow-green mutant of wheat (Triticum durum var Cappelli) and its wild type strain grown in the field. All these parameters, expressed on leaf area basis, were similar in both genotypes except electron transport which was more than double in the wild type. These results, treated according to a recent photosynthesis model for C(3) plants, seem to indicate that the electron transport rate of mutant leaves is not sufficient to support the carboxylation derived through both the assimilation rate and the in vitro ribulose-1,5-bisphosphate carboxylase activity. It is suggested that under our experimental conditions photosynthetic electron transport is not the sole energy-dependent determinant of ribulose-1,5-bisphosphate regeneration in the mutant.