RESUMO
Brain development during childhood and early adolescence is characterized by global changes in brain architecture. Neuroimaging studies have revealed overall decreases in cortical thickness (CT) and increases in fractional anisotropy (FA). Furthermore, previous studies have shown that certain cortical regions display coordinated growth during development. However, there is significant heterogeneity in the timing and speed of these developmental transformations, and it is still unclear whether white and grey matter changes are co-localized. In this multimodal neuroimaging study, we investigated the relationship between grey and white matter developmental changes and asynchronous maturation within brain regions in 249 normally developing children between the ages 7-14. We used structural magnetic resonance imaging (MRI) and diffusion tensor imaging (DTI) to analyze CT and FA, respectively, as well as their covariance across development. Consistent with previous studies, we observed overall cortical thinning with age, which was accompanied by increased FA. We then compared the coordinated development of grey and white matter as indexed by covariance measures. Covariance between grey matter regions and the microstructure of white matter tracts connecting those regions were highly similar, suggesting that coordinated changes in the cortex were mirrored by coordinated changes in their respective tracts. Examining within-brain divergent trajectories, we found significant structural decoupling (decreased covariance) between several brain regions and tracts in the 9- to 11-year-old group, particularly involving the forceps minor and the regions that it connects to. We argue that this decoupling could reflect a developmental pattern within the prefrontal region in 9- and 11-year-old children, possibly related to the significant changes in cognitive control observed at this age.
Assuntos
Encéfalo/diagnóstico por imagem , Encéfalo/crescimento & desenvolvimento , Substância Cinzenta/diagnóstico por imagem , Substância Cinzenta/crescimento & desenvolvimento , Substância Branca/diagnóstico por imagem , Substância Branca/crescimento & desenvolvimento , Adolescente , Criança , Estudos Transversais , Imagem de Difusão por Ressonância Magnética , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Imagem Multimodal , Tamanho do ÓrgãoRESUMO
BACKGROUND: Neurodevelopmental alterations have been described inconsistently in psychosis probably because of lack of standardization among studies. The aim of this study was to conduct the first longitudinal and population-based magnetic resonance imaging (MRI) evaluation of the presence and size of the cavum septum pellucidum (CSP) and adhesio interthalamica (AI) in a large sample of patients with first-episode psychosis (FEP). METHOD: FEP patients (n=122) were subdivided into schizophrenia (n=62), mood disorders (n=46) and other psychosis (n=14) groups and compared to 94 healthy next-door neighbour controls. After 13 months, 80 FEP patients and 52 controls underwent a second MRI examination. RESULTS: We found significant reductions in the AI length in schizophrenia FEP in comparison with the mood disorders and control subgroups (longer length) at the baseline assessment, and no differences in any measure of the CSP. By contrast, there was a diagnosis×time interaction for the CSP length, with a more prominent increase for this measure in the psychosis group. There was an involution of the AI length over time for all groups but no diagnosis×time interaction. CONCLUSIONS: Our findings suggest that the CSP per se may not be linked to the neurobiology of emerging psychotic disorders, although it might be related to the progression of the disease. However, the fact that the AI length was shown to be shorter at the onset of the disorder supports the neurodevelopmental model of schizophrenia and indicates that an alteration in this grey matter junction may be a risk factor for developing psychosis.
Assuntos
Interpretação de Imagem Assistida por Computador , Imageamento por Ressonância Magnética , Transtornos do Humor/diagnóstico , Transtornos Psicóticos/diagnóstico , Esquizofrenia/diagnóstico , Septo Pelúcido/anormalidades , Septo Pelúcido/patologia , Tálamo/anormalidades , Tálamo/patologia , Adulto , Brasil , Estudos Transversais , Progressão da Doença , Feminino , Humanos , Incidência , Estudos Longitudinais , Masculino , Transtornos do Humor/epidemiologia , Tamanho do Órgão , Transtornos Psicóticos/epidemiologia , Valores de Referência , Fatores de Risco , Esquizofrenia/epidemiologia , Fatores Sexuais , Adulto JovemRESUMO
BACKGROUND: Some neuroimaging studies have supported the hypothesis of progressive brain changes after a first episode of psychosis. We aimed to determine whether (i) first-episode psychosis patients would exhibit more pronounced brain volumetric changes than controls over time and (ii) illness course/treatment would relate to those changes. METHOD: Longitudinal regional grey matter volume and ventricle:brain ratio differences between 39 patients with first-episode psychosis (including schizophrenia and schizophreniform disorder) and 52 non-psychotic controls enrolled in a population-based case-control study. RESULTS: While there was no longitudinal difference in ventricle:brain ratios between first-episode psychosis subjects and controls, patients exhibited grey matter volume changes, indicating a reversible course in the superior temporal cortex and hippocampus compared with controls. A remitting course was related to reversal of baseline temporal grey matter deficits. CONCLUSIONS: Our findings do not support the hypothesis of brain changes indicating a progressive course in the initial phase of psychosis. Rather, some brain volume abnormalities may be reversible, possibly associated with a better illness course.
Assuntos
Encéfalo/patologia , Transtornos Psicóticos/patologia , Adulto , Estudos de Casos e Controles , Progressão da Doença , Feminino , Humanos , Estudos Longitudinais , Imageamento por Ressonância Magnética , Masculino , Esquizofrenia/patologia , Fatores SocioeconômicosRESUMO
Panic disorder is thought to involve dysfunction in the septohippocampal system, and the presence of a cavum septum pellucidum might indicate the aberrant development of this system. We compared the prevalence and size of cavum septum pellucidum in 21 patients with panic disorder and in 21 healthy controls by magnetic resonance imaging. The length of the cavum septum pellucidum was measured by counting the number of consecutive 1-mm coronal slices in which it appeared. A cavum septum pellucidum of >6 mm in length was rated as large. There was no significant difference in the proportion of patients (16 of 21 or 76.2%) and controls (18 of 21 or 85.7%) with a cavum septum pellucidum (P=0.35, Fisher's exact test, one-tailed), and no members of either group had a large cavum septum pellucidum. The mean cavum septum pellucidum rating in the patient and control groups was 1.81 (SD=1.50) and 2.09 (SD=1.51), respectively. There were also no significant differences between groups when we analyzed cavum septum pellucidum ratings as a continuous variable (U=196.5; P=0.54). Across all subjects there was a trend towards a higher prevalence of cavum septum pellucidum in males (100%, 10 of 10) than females (75%, 24 of 32; P=0.09, Fisher's exact test, one-tailed). Thus, we conclude that, while panic disorder may involve septo-hippocampal dysfunction, it is not associated with an increased prevalence or size of the cavum septum pellucidum.
Assuntos
Transtorno de Pânico/patologia , Septo Pelúcido/anormalidades , Adulto , Estudos de Casos e Controles , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Prevalência , Septo Pelúcido/patologiaRESUMO
Panic disorder is thought to involve dysfunction in the septohippocampal system, and the presence of a cavum septum pellucidum might indicate the aberrant development of this system. We compared the prevalence and size of cavum septum pellucidum in 21 patients with panic disorder and in 21 healthy controls by magnetic resonance imaging. The length of the cavum septum pellucidum was measured by counting the number of consecutive 1-mm coronal slices in which it appeared. A cavum septum pellucidum of >6 mm in length was rated as large. There was no significant difference in the proportion of patients (16 of 21 or 76.2 percent) and controls (18 of 21 or 85.7 percent) with a cavum septum pellucidum (P = 0.35, Fisher's exact test, one-tailed), and no members of either group had a large cavum septum pellucidum. The mean cavum septum pellucidum rating in the patient and control groups was 1.81 (SD = 1.50) and 2.09 (SD = 1.51), respectively. There were also no significant differences between groups when we analyzed cavum septum pellucidum ratings as a continuous variable (U = 196.5; P = 0.54). Across all subjects there was a trend towards a higher prevalence of cavum septum pellucidum in males (100 percent, 10 of 10) than females (75 percent, 24 of 32; P = 0.09, Fisher's exact test, one-tailed). Thus, we conclude that, while panic disorder may involve septo-hippocampal dysfunction, it is not associated with an increased prevalence or size of the cavum septum pellucidum.
Assuntos
Humanos , Masculino , Feminino , Transtorno de Pânico , Septo Pelúcido , Estudos de Casos e Controles , Imageamento por Ressonância Magnética , PrevalênciaRESUMO
OBJECTIVE: Recent epidemiological and clinical data suggest that obsessive-compulsive disorder (OCD) may be subtyped according the age of onset of obsessive-compulsive symptoms. The regional cerebral blood flow (rCBF) single photon emission computed tomography (SPECT) technique was used to investigate whether the pathophysiology of OCD differs between early- and late-onset OCD subjects. METHOD: Resting rCBF was measured in 13 early-onset (<10 years) and 13 late-onset (>12 years) adult OCD subjects and in 22 healthy controls. Voxel-based rCBF comparisons were performed with statistical parametric mapping. RESULTS: Early-onset OCD cases showed decreased rCBF in the right thalamus, left anterior cingulate cortex, and bilateral inferior prefrontal cortex relative to late-onset subjects (p < .0005, uncorrected for multiple comparisons). Relative to controls, early-onset cases had decreased left anterior cingulate and right orbitofrontal rCBF, and increased rCBF in the right cerebellum, whereas late-onset subjects showed reduced right orbitofrontal rCBF and increased rCBF in the left precuneus. In early-onset subjects only, severity of obsessive-compulsive symptoms correlated positively with left orbitofrontal rCBF. CONCLUSIONS: rCBF differences in frontal-subcortical circuits between early-onset and late-onset OCD subjects were found, both in location and direction of changes. These results provide preliminary evidence that brain mechanisms in OCD may differ depending on the age at which symptoms are first expressed.
Assuntos
Encéfalo/irrigação sanguínea , Transtorno Obsessivo-Compulsivo/patologia , Adolescente , Adulto , Idade de Início , Encéfalo/diagnóstico por imagem , Encéfalo/patologia , Estudos de Casos e Controles , Criança , Feminino , Humanos , Masculino , Transtorno Obsessivo-Compulsivo/diagnóstico por imagem , Fluxo Sanguíneo Regional , Tomografia Computadorizada de Emissão de Fóton ÚnicoRESUMO
Several functional imaging studies have reported abnormalities of the orbitofrontal and anterior cingulate cortices, striatum and thalamus in obsessive-compulsive disorder (OCD). These studies have often been limited by small patient samples and image analysis methods that rely on region-of-interest (ROI) approaches. We have assessed resting regional cerebral blood flow with 99mTc-ECD SPECT in 26 unmedicated OCD patients and 22 healthy control subjects using the voxel-based Statistical Parametric Mapping method for data analysis. We found a significantly reduced ECD uptake in OCD patients relative to the control subjects in the right lateral orbitofrontal cortex, and in the left dorsal anterior cingulate cortex (P<0.001 two-tailed, uncorrected for multiple comparisons). There were significant positive correlations in the OCD group between the ECD uptake in the left lateral orbitofrontal cortex and ratings for obsessive-compulsive symptoms (OCS), and between the ECD uptake in the right medial orbitofrontal cortex and the ratings for both OCS and depressive symptoms. There were also unpredicted significant ECD uptake increases in the cerebellum in OCD patients, as well as a negative correlation between posterior cingulate ECD uptake and OCS severity (P<0.05, corrected for multiple testing). These results implicate specific subregions of the orbitofrontal and anterior cingulate cortices in the pathophysiology of OCD, as well as suggesting the involvement of other areas not usually included in ROI-based imaging studies. With the incorporation of voxel-based methods and the use of large patient samples, rCBF-SPECT studies may continue to provide valuable information about the functional anatomy of OCD.
Assuntos
Encéfalo/irrigação sanguínea , Encéfalo/diagnóstico por imagem , Transtorno Obsessivo-Compulsivo/diagnóstico , Tomografia Computadorizada de Emissão de Fóton Único , Adulto , Feminino , Humanos , Masculino , Fluxo Sanguíneo Regional/fisiologiaRESUMO
To resolve the population genetic structure and phylogeography of the West Indian manatee (Trichechus manatus), mitochondrial (mt) DNA control region sequences were compared among eight locations across the western Atlantic region. Fifteen haplotypes were identified among 86 individuals from Florida, Puerto Rico, the Dominican Republic, Mexico, Columbia, Venezuela, Guyana and Brazil. Despite the manatee's ability to move thousands of kilometers along continental margins, strong population separations between most locations were demonstrated with significant haplotype frequency shifts. These findings are consistent with tagging studies which indicate that stretches of open water and unsuitable coastal habitats constitute substantial barriers to gene flow and colonization. Low levels of genetic diversity within Florida and Brazilian samples might be explained by recent colonization into high latitudes or bottleneck effects. Three distinctive mtDNA lineages were observed in an intraspecific phylogeny of T. manatus, corresponding approximately to: (i) Florida and the West Indies; (ii) the Gulf of Mexico to the Caribbean rivers of South America; and (iii) the northeast Atlantic coast of South America. These lineages, which are not concordant with previous subspecies designations, are separated by sequence divergence estimates of d = 0.04-0.07, approximately the same level of divergence observed between T. manatus and the Amazonian manatee (T. inunguis, n = 16). Three individuals from Guyana, identified as T. manatus, had mtDNA haplotypes which are affiliated with the endemic Amazon form T. inunguis. The three primary T. manatus lineages and the T. inunguis lineage may represent relatively deep phylogeographic partitions which have been bridged recently due to changes in habitat availability (after the Wisconsin glacial period, 10 000 B P), natural colonization, and human-mediated transplantation.
Assuntos
DNA Mitocondrial/química , Geografia , Mamíferos/classificação , Filogenia , Animais , Sequência de Bases , Brasil , Região do Caribe , Bovinos , Primers do DNA/química , DNA Mitocondrial/sangue , Florida , Haplótipos/genética , Região de Controle de Locus Gênico , Mamíferos/genética , Camundongos , Dados de Sequência Molecular , Reação em Cadeia da Polimerase , Dinâmica Populacional , Alinhamento de Sequência , Análise de Sequência de DNA , Homologia de Sequência do Ácido NucleicoRESUMO
This is an interval analysis of the 2-year prospective multicenter Childrens Cancer Study Group study of 1,141 chronic venous access devices in 1,019 children with cancer. Device type was external catheter (EC) 72%, totally implantable (TID) 28%, and did not differ for diagnosis or age except more double-lumen devices in bone marrow transplant protocols (77%) and more TIDs in children less than 1 year old (17.7%). Insertion characteristics evaluated in 1,078 (95%) were: operating room placement 99%; general anesthesia 98%; cutdown 67%; percutaneous 33%; atrial position 50%, caval position 50%; and perioperative antibiotics 48%. Vein entry was the external jugular 33%, internal jugular 22%, subclavian 35%, cephalic 7%, and saphenous 3%. Insertion was difficult or very difficult in only 10% and operative complications occurred in only 0.7%. Degree of difficulty bore no relationship to device type or patient age. The reasons for removal in 736 devices (67%) were due to complications in 39%, of which infections were the most frequent. There was some variance between centers ranging from 8.5% to 31% for infection; 2.8% to 24% for dislodgment; and 0% to 13% for occlusion. ECs had a higher risk of dislodgment; elective removals were more frequent in TIDs; there was no difference in infection as a cause for removal between ECs and TIDs. Dislodgment was associated with the shortest distance of the cuff to the skin exit (mean, 4 cm): less than or equal to 2 cm, 49%; greater than 2 cm, 28% (P = .009) and occurred most frequently in the younger patient (18.9%, 0 to 1 years; 0.5%, greater than 8 years.