Biomedical subjects

Claudio C de Castro

Publications and source records attributed to Claudio C de Castro.

4 recordsLinked to original sources

PubMed2006

Volumetric reduction of the corpus callosum in Alzheimer's disease in vivo as assessed with voxel-based morphometry.

Several recent magnetic resonance imaging studies have employed voxel-based morphometry (VBM) to detect regional gray matter volume abnormalities in Alzheimer's disease (AD). However, investigations of corpus callosum (CC) abnormalities in AD using this automated methodology have been scarce, and no VBM study investigated correlations between regional CC atrophy and cognitive measurements in AD subjects at mild disease stages. We used VBM to compare the topography of CC volume differences between 14 AD subjects (MMSE 14-25) and 14 healthy volunteers. Images were acquired using a 1.5-Telsa scanner, and were spatially normalized and segmented using optimized VBM. Statistical comparisons were performed using the general linear model. Significant CC atrophy was detected in the antero-superior portion of the splenium, the isthmus, the anterior and posterior portions of the CC body, and the rostral portion of the genu. Voxels showing peak statistical difference were all left-sided (P<0.001, uncorrected for multiple comparisons). A cluster of significant positive correlation with MMSE scores was seen on the left anterior CC body. Our results confirm previous findings of diffuse volumetric CC reductions early in the course of AD, and warrant further evaluation of the relevance of atrophic changes in anterior CC portions to the cognitive impairments that characterize the disorder.

Aged↗

PubMed2006

A 1HMRS study of the anterior cingulate gyrus in euthymic bipolar patients.

INTRODUCTION: The anterior cingulate region has been implicated in the pathophysiology of mood disorders. Studies have reported anatomical and functional abnormalities in this region in bipolar disorder patients. Few neurochemical studies have evaluated this region, especially on medicated bipolar patients. Lithium has been reported to increase NAA levels but not by all studies. We used proton magnetic spectroscopy ((1)HMRS) to measure the levels of N-acetyl-L-aspartate (NAA) and choline (Cho) relative to creatine (Cr) in the anterior cingulate of euthymic medicated bipolar subjects. METHODS: (1)HMRS was performed using a GE Signa 1.5 Tesla scanner in 13 euthymic bipolar patients who were taking lithium for at least four weeks before the scan and in 15 normal controls. The (1)HMRS signal was collected from an 8 cm(3) voxel placed in the anterior cingulate. Data analysis was performed with the automated PROBE/SV quantification tool. RESULTS: NAA/Cr and Cho/Cr ratios were not significantly different between patients and controls (NAA/Cr: 1.60 +/- 0.34 in patients, 1.68 +/- 0.34 in controls; Cho/Cr: 1.13 +/- 0.13 in patients, 1.11 +/- 0.20 in controls). CONCLUSIONS: We did not find a significant difference in the NAA/Cr and Cho/Cr ratio between bipolar patients and healthy controls. Chronic administration of psychotropic drugs could have had an effect on NAA/Cr levels of bipolar patients.

Adult↗

PubMed2004

Widespread electrical cortical dysfunction in schizophrenia.

The purpose of this study was to compare slow cortical electrical activity between healthy and schizophrenic individuals using 123-channel EEG and current density reconstruction (CDR). Twenty-nine healthy subjects and 14 drug-free patients performed three visual paired-associate tasks (verbal, pictorial and spatial). We modeled the generators of the slow potentials (SPs) at their peak amplitude by Lp-norm minimization using individual MRIs to model the volume conductor and source. Activity in each architectonic area of Brodmann was scored with respect to individual maximum current by a percentile method. Resulting scores by cortical area were analyzed by multivariate analysis of variance (MANOVA) with planned comparisons, to search for differences among levels. Results showed a multifocal pattern of current density foci comprising the SP generators, including frontal and posterior cortices in all subjects. A few cortical areas, not exclusively frontal, were observed to significantly differ between groups. Moreover, changes in patients' frontal activity were not exclusively to lower scores or 'hipofrontality': overall effects (all tasks collapsed) included increased electrical activity in right area 10, left 38 and 47 bilaterally, and decreased activity in right area 6 and left areas 39, 21 and 19. A few additional areas showed significantly altered activity only in particular tasks. We conclude that the present method, by preserving individual anatomical and functional information, indicates bidirectional patterns of altered electrical activity in specific cortical association areas in schizophrenia, which are not compatible with the exclusive 'hipofrontality' hypothesis. Our results agree with the hypothesis of schizophrenia as a syndrome resulting from abnormalities in multiple encephalic foci.

Adult↗

PubMedDate not supplied

Gadolinium-enhanced three-dimensional MR angiography of Takayasu arteritis.

Takayasu arteritis is a form of large vessel vasculitis with a possible autoimmune origin that may cause stenosis of the aorta and its major branches. Six types of Takayasu arteritis are recognized; the type depends on whether the ascending aorta, descending thoracic aorta, abdominal aorta, aortic cervicobrachial branches, or renal arteries are affected. The coronary and pulmonary arteries are also sometimes involved. Clinical features of the disease include diminished or absent pulses, claudication, hypertension, and mesenteric angina. Conventional angiography has been the standard imaging tool for diagnosis and evaluation of Takayasu arteritis, although it demonstrates only the lumen of the vessel. Less invasive cross-sectional methods such as computed tomographic angiography and, more recently, three-dimensional magnetic resonance (MR) angiography can effectively demonstrate thickening of the vessel wall, which may be the earliest manifestation of the disease, occurring before stenosis and dilatation. MR imaging in particular allows better soft-tissue differentiation and can show other signs of inflammation, including mural edema and increased mural vascularity. Other advantages of MR imaging are the lack of iodinated contrast material or ionizing radiation.

Adolescent↗