Short echo time MR spectroscopy of brain tumors: grading of cerebral gliomas by correlation analysis of normalized spectral amplitudes.

PURPOSE: To process single voxel spectra of low- and high-grade gliomas. To propose correlation analysis of the scatter plots of normalized spectral amplitudes as a pattern recognition tool for the classification (grading) of brain tumors. To propose a spectrum processing approach that improves the differentiation of proton spectra with dominating macromolecule and lipid peaks. MATERIALS AND METHODS: LCModel was used to process spectra. Mean metabolite concentrations and mean normalized spectra were obtained for normal white matter and for gliomas. The mean spectra of macromolecules and lipids (ML) in the range 1.4-0.9 ppm, and mean difference spectra (DS) without ML and lactate were computed. Correlation analysis of the scatter plot of the patient and mean normalized spectral amplitudes and dispersion of the scatter plot points were used for classification and grading of tumors. RESULTS: It was found advantageous to perform the classifications using DS spectra. The shape of ML spectrum and concentration of tCr seem to be a good markers for glioma grade. CONCLUSION: Combining a qualitative comparison of the patient and mean DS spectra of the tumors using correlation analysis of normalized spectra amplitudes with a quantitative comparison of metabolite concentrations is a powerful tool in studying brain lesions.

[Deep brain stimulation can break vicious circle in obsessive-compulsive disorder]. / Djup hjärnstimulering kan bryta ond cirkel vid tvångssyndrom.

Obsessive-compulsive disorder (OCD), characterized by repetitive intrusive thoughts and ritualized behaviors, is a highly debilitating disorder with an estimated lifetime prevalence of about 2 %. Approximately 10 % of these patients have severe symptoms despite having received all available treatments, thus considered treatment refractory. Deep brain stimulation (DBS), a reversible, safe and adaptive method widely used for movement disorders, enables specific targeting of deep brain structures of relevance in OCD. About 60% of the patients with treatment refractory OCD show ameliorated symptoms and improved quality of life with DBS. Taking ethical aspects into consideration DBS is a viable option for patients with treatment refractory OCD though further studies are needed to fully understand and individualize this treatment.

Platelet-derived growth factor-BB modulates membrane mobility of beta1 integrins.

Platelet-derived growth factor (PDGF)-BB elicits a migratory response including reorganization of the actin cytoskeleton in different cell types. Here we have investigated the effects of PDGF-BB stimulation on beta(1) integrin containing focal adhesions in human diploid fibroblasts adhered to collagen type I. Stimulation with PDGF-BB dissociated focal adhesions and relocated beta(1) integrins from focal adhesions to the periphery of the cells. These changes were rapid and transient in character. Relocation of beta(1) integrins was prevented by inhibitors of phosphoinositide-3-kinase and protein kinase C. PDGF-BB stimulated fibroblasts exhibited an increased diffusion coefficient of cell surface beta(1) integrins as determined by fluorescence recovery of photobleaching. The cell surface expression of beta(1) integrins was not changed after stimulation with PDGF-BB. Our data suggest that PDGF-BB increases the dynamic properties of cell-surface beta(1) integrins, which most likely are important for the migratory response elicited by PDGF-BB.