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    Paulo Sallet

    -In recent decades, the high prevalence of obesity in the general population has brought serious concerns in terms of public health. Contrarily to conventional treatment involving dieting and physical exercising, often ineffective in... more
    -In recent decades, the high prevalence of obesity in the general population has brought serious concerns in terms of public health. Contrarily to conventional treatment involving dieting and physical exercising, often ineffective in generating long term results, bariatric opera-tions have been an effective method for sustained weight loss in morbidly obese individuals. The Bariatric Analysis and Reporting Outcome System (BAROS) is an objective and recognized system in the overall evaluation of results after bariatric surgery. - To investigate results concerning a casuistic of morbidly obese patients undergoing bariatric surgery over a 2-year follow-up in terms of weight loss, related medical conditions, safety and changes in quality of life. - A total of 120 obese (17 male and 103 female) patients, who underwent bariatric surgery, were assessed and investigated using the BAROS system after a 2- year follow-up. - Patients obtained a mean excess weight loss of 74.6 (±15.9) % and mean body mass index reduction of 15.6 (±4.4) Kg/m2. Pre-surgical comorbidities were present in 71 (59%) subjects and they were totally (86%) or partially (14%) resolved. Complications resulting specifically from the surgical procedure were observed in 4.2% of cases (two bowel obstructions requiring re-operation, and three stomal stenosis treated with endoscopic dilation). Sixteen subjects (13% of total number of patients) presented minor clinical complications managed through outpatient care. The final scores for the BAROS questionnaire showcased excellent to good results in 99% of cases (excellent 44%, very good 38%, good 23%, acceptable 1%). - According to the BAROS questionnaire, bariatric surgery is a safe and effective method for managing obesity and associated clinical comorbidities, allowing for satisfactory results after a 2-year follow-up. Future studies should address other clinical and psychosocial variables that impact outcome as well as allow for longer follow-ups.
    Structural brain abnormalities in schizophrenia have been repeatedly demonstrated in magnetic resonance imaging (MRI) studies, but it remains unclear whether these are static or progressive in nature. While longitudinal MRI studies have... more
    Structural brain abnormalities in schizophrenia have been repeatedly demonstrated in magnetic resonance imaging (MRI) studies, but it remains unclear whether these are static or progressive in nature. While longitudinal MRI studies have been traditionally used to assess the issue of progression of brain abnormalities in schizophrenia, information from cross-sectional neuroimaging studies directly comparing first-episode and chronic schizophrenia patients to healthy controls may also be useful to further clarify this issue. With the recent interest in multisite mega-analyses combining structural MRI data from multiple centers aiming at increased statistical power, the present multisite voxel-based morphometry (VBM) study was carried out to examine patterns of brain structural changes according to the different stages of illness and to ascertain which (if any) of such structural abnormalities would be specifically correlated to potential clinical moderators, including cumulative exposure to antipsychotics, age of onset, illness duration and overall illness severity. We gathered a large sample of schizophrenia patients (161, being 99 chronic and 62 first-episode) and controls (151) from four previous morphometric MRI studies (1.5 T) carried out in the same geographical region of Brazil. Image processing and analyses were conducted using Statistical Parametric Mapping (SPM8) software with the diffeomorphic anatomical registration through exponentiated Lie algebra (DARTEL) algorithm. Group effects on regional gray matter (GM) volumes were investigated through whole-brain voxel-wise comparisons using General Linear Model Analysis of Co-variance (ANCOVA), always including total GM volume, scan protocol, age and gender as nuisance variables. Finally, correlation analyses were performed between the aforementioned clinical moderators and regional and global brain volumes. First-episode schizophrenia subjects displayed subtle volumetric deficits relative to controls in a circumscribed brain regional network identified only in small volume-corrected (SVC) analyses (p < 0.05, FWE-corrected), including the insula, temporolimbic structures and striatum. Chronic schizophrenia patients, on the other hand, demonstrated an extensive pattern of regional GM volume decreases relative to controls, involving bilateral superior, inferior and orbital frontal cortices, right middle frontal cortex, bilateral anterior cingulate cortices, bilateral insulae and right superior and middle temporal cortices (p < 0.05, FWE-corrected over the whole brain). GM volumes in several of those brain regions were directly correlated with age of disease onset on SVC analyses for conjoined (first-episode and chronic) schizophrenia groups. There were also widespread foci of significant negative correlation between duration of illness and relative GM volumes, but such findings remained significant only for the right dorsolateral prefrontal cortex after accounting for the influence of age of disease onset. Finally, significant negative correlations were detected between life-time cumulative exposure to antipsychotics and total GM and white matter volumes in schizophrenia patients, but no significant relationship was found between indices of antipsychotic usage and relative GM volume in any specific brain region. The above data indicate that brain changes associated with the diagnosis of schizophrenia are more widespread in chronic schizophrenia compared to first-episode patients. Our findings also suggest that relative GM volume deficits may be greater in (presumably more severe) cases with earlier age of onset, as well as varying as a function of illness duration in specific frontal brain regions. Finally, our results highlight the potentially complex effects of the continued use of antipsychotic drugs on structural brain abnormalities in schizophrenia, as we found that cumulative doses of antipsychotics affected brain volumes globally rather than selectively on frontal-temporal regions.
    Background / Purpose: Several theoretical models consider that white matter (WM) abnormalities have a central role in the pathophysiology of schizophrenia, and brain imaging studies have found WM abnormalities in individuals with both... more
    Background / Purpose: Several theoretical models consider that white matter (WM) abnormalities have a central role in the pathophysiology of schizophrenia, and brain imaging studies have found WM abnormalities in individuals with both recent-onset and chronic psychosis. However, no study to date has investigated whether these changes are stable or state-dependent, i.e., varying according to the acute versus remitted phase of the disorder. In this study, we aim to evaluate the WM microstructure using diffusion tensor imaging (DTI) in a group of patients with non-affective first-episode psychosis (FEP) at the acute psychotic state and after symptomatic remission. Main conclusion: Our findings suggest that some WM changes present in the very beginning of FEP could reverse following symptom remission. It may be possible that such changes affecting brain areas related to the integration of perceptual information, could partially underpin the emergence of symptoms in FEP.
    Research Interests:
    An abnormality in neurodevelopment is one of the most robust etiologic hypotheses in schizophrenia (SZ). There is also strong evidence that genetic factors may influence abnormal neurodevelopment in the disease. The present study... more
    An abnormality in neurodevelopment is one of the most robust etiologic hypotheses in schizophrenia (SZ). There is also strong evidence that genetic factors may influence abnormal neurodevelopment in the disease. The present study evaluated in SZ patients, whose brain structural data had been obtained with magnetic resonance imaging (MRI), the possible association between structural brain measures, and 32 DNA polymorphisms,
    RESUMO Os autores discutem os principais achados de neuroimagem envolvendo subtipos diagnósticos da classificação das psicoses endógenas de Karl Leonhard, enfatizando a hipótese de que os aspectos clínicos e nosológicos possam oferecer... more
    RESUMO Os autores discutem os principais achados de neuroimagem envolvendo subtipos diagnósticos da classificação das psicoses endógenas de Karl Leonhard, enfatizando a hipótese de que os aspectos clínicos e nosológicos possam oferecer subtipos mais homogêneos à investigação neurobiológica. Os estudos com tomografia computadorizada (CT - computed tomography) sugerem que as psicoses ciclóides apresentam predomínio de alterações estruturais caracterizadas por alargamento
    Neurobiological, genetic, and psychopharmacological findings in the diagnostic subtypes of Leonhard's classification The classification of endogenous psychoses provides subpopulations of psychoses with more homogeneous clinical and... more
    Neurobiological, genetic, and psychopharmacological findings in the diagnostic subtypes of Leonhard's classification The classification of endogenous psychoses provides subpopulations of psychoses with more homogeneous clinical and prognostic characteristics. The present paper consists in a summarized review of the main neurobiological findings involving diagnostic subtypes according to the Leonhard's classification. The genetic-environmental findings suggest that cycloid psychoses and systematic schizophrenias show
    The aim of this article is to propose an integrated framework for extracting and describing patterns of disorders from medical images using a combination of linear discriminant analysis and active contour models. A multivariate... more
    The aim of this article is to propose an integrated framework for extracting and describing patterns of disorders from medical images using a combination of linear discriminant analysis and active contour models. A multivariate statistical methodology was first used to identify the most discriminating hyperplane separating two groups of images (from healthy controls and patients with schizophrenia) contained in the input data. After this, the present work makes explicit the differences found by the multivariate statistical method by subtracting the discriminant models of controls and patients, weighted by the pooled variance between the two groups. A variational level-set technique was used to segment clusters of these differences. We obtain a label of each anatomical change using the Talairach atlas. In this work all the data was analysed simultaneously rather than assuming a priori regions of interest. As a consequence of this, by using active contour models, we were able to obtai...
    ... still unknown1 . Both genetic (Harrison and Owen, 2003) and environmental factors (including biological - eg, prenatal infection and obstetric complications - and psychosocial factors) appear to play a role in its etiology. These ...
    Although well documented, brain structural abnormalities in schizophrenia are non-specific, and morphometric parameters show significant overlap between patients and healthy controls. Such inconsistencies in neuroimaging findings could... more
    Although well documented, brain structural abnormalities in schizophrenia are non-specific, and morphometric parameters show significant overlap between patients and healthy controls. Such inconsistencies in neuroimaging findings could represent different levels of severity along a single pathogenic process or distinct clinical and etiopathological psychoses within a schizophrenic spectrum. The aim of the present study was the investigation of distinct brain abnormalities in different subtypes of schizophrenia. Forty patients were classified according to DSM-IV and Leonhard's classifications. Psychopathology was assessed by the Positive and Negative Syndrome Scale (PANSS) and the Negative Symptom Rating Scale (NSRS). Patients were compared to 20 healthy volunteers on volumetric measures of cerebral structures (hemisphere, hippocampus and planum temporale) and ventricular-brain ratio (VBR) obtained by magnetic resonance imaging. Patients showed rightward asymmetry of cerebral hemispheres and increased VBR. Rightward asymmetry correlated with severity of negative symptoms and prevailed in the systematic forms of Leonhard, suggesting a distinct pattern of left hemisphere abnormality in this subgroup of psychoses. Increased VBR values showed a single normal distribution in the subgroups, indicating that ventricular enlargement is not restricted to a subgroup but is present to a certain degree in all cases.