[Brain metabolism alterations in patients with anorexia nervosa observed in 1H-MRS]

Contains fulltext : 48323.pdf (publisher's version ) (Open Access)The causes of metabolic brain changes in patients with anorexia nervosa are still not fully explained. The purpose of this study was to use the 1H-MRS method in investigating metabolic changes in the brain of patients with anorexia nervosa. We studied 10 patients for visible alternations in brain metabolism and compared the results to healthy controls. 1H-MRS was acquired by the method of single voxels in white and grey matter. Proton MRS was performed after image guided localization using stimulated echo acquisition mode (STEAM) sequence with a short echo time of 20 ms. For data evaluation we used standard Siemens software and the additional PC. Choosing of the MRS sequences was related with particular interest in metabolites of short time echo: myoinositol and lipids. Besides this we evaluated peaks of: N-acetylaspartate (NAN), creatine (Cr) and choline (Cho). The results show significant differences in the levels of metabolites connected with fatty metabolism. In white matter we observed the reduction of lip-peak. The data was evaluated approximately and presented as lip:Cr. We did not observe any differences in other metabolites. As far as we know similar results had been reported and our study confirmed significant disorders in metabolism of these chemicals in patients with anorexia nervosa

Mitochondrial potassium channel Kv1.3 mediates Bax-induced apoptosis in lymphocytes

The potassium channel Kv1.3 has recently been located to the inner mitochondrial membrane of lymphocytes. Here, we show that mouse and human cells that are genetically deficient in either Kv1.3 or transfected with siRNA to suppress Kv1.3-expression resisted apoptosis induced by several stimuli, including Bax over-expression. Retransfection of either Kv1.3 or a mitochondrial-targeted Kv1.3 restored cell death. Bax interacted with and functionally inhibited mitochondrial Kv1.3. Incubation of isolated Kv1.3-positive mitochondria with recombinant Bax, t-Bid, or toxins that bind to and inhibit Kv1.3 successively triggered hyperpolarization, formation of reactive oxygen species, release of cytochrome c, and marked depolarization. Kv1.3-deficient mitochondria were resistant to Bax, t-Bid, and the toxins. Mutation of Bax at K128, which corresponds to a conserved lysine in Kv1.3-inhibiting toxins, abrogated its effects on both Kv1.3 and mitochondria. These findings suggest that Bax mediates cytochrome c release and mitochondrial depolarization in lymphocytes, at least in part, via its interaction with mitochondrial Kv1.3