963 resultados para BRAIN-REGIONS
Resumo:
Several epidemiological studies have linked particulate matter exposure to numerous adverse health effects on the respiratory, cardiovascular, and reproductive systems (Braga et al., 1999; Zanobetti et al., 2000; Anderson et al., 2001; Farhat et al., 2005). More recently, ambient levels of black carbon were associated to impaired cognitive function in children (Suglia et al., 2008), suggesting that the central nervous system (CNS) may be a target of air pollutants. The present study was conducted to (a) determine whether chronic residual oil fly ash (ROFA) exposure promotes behavioral changes and lipid peroxidation in rat brain areas, and (b) determine whether N-acetylcysteine (NAC), a general antioxidant, prevents these effects. Forty-five-day-old male Wistar rats were exposed or not to ROFA by intranasal instillation and were treated or not with NAC (150 mg/kg) ip for 30 days. One day later, rats were submitted to the open field test to evaluate the motor/exploratory activities and emotionality followed by decapitation. Striatum and cerebellum were dissected to determine lipid peroxidation by the accumulation of thiobarbituric acid-reactive substances (TBARS). ROFA instillation induced an increase in lipid peroxidation level in striatum (p = .033) and cerebellum (p = .030), as compared with the control group. NAC treatment blocked these changes. ROFA promoted a decrease in the frequency of peripheral walking (p = .006) and a decrease in exploration (p = .001), which were not blocked by N-acetylcysteine. The present study provides evidence that toxic particles, administered by the respiratory route, induce oxidative stress in structures of the central nervous system, as well as behavioral alterations. The administration of NAC reduces lipid peroxidation at the striatum and cerebellum levels, but does not influence behavioral disturbances.
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Objective: To compare the volume of the hippocampus and parahippocampal gyrus in elderly individuals with and without depressive disorders, and to determine whether the volumes of these regions correlate with scores on memory tests. Method: Clinical and demographic differences, as well as differences in regional gray matter volumes, were assessed in 48 elderly patients with depressive disorders and 31 control subjects. Brain (structural MRI) scans were processed using statistical parametric mapping and voxel-based morphometry. Cognitive tests were administered to subjects in both groups. Results: There were no between-group gray matter volume differences in the hippocampus or parahippocampal gyrus. In the elderly depressed group only, the volume of the left parahippocampal gyrus correlated with scores on the delayed naming portion of the visual verbal learning test. There were also significant direct correlations in depressed subjects between the volumes of the left hippocampus, right and left parahippocampal gyrus and immediate recall scores on verbal episodic memory tests and visual learning tests. In the control group, there were direct correlations only between overall cognitive performance (as assessed with the MMSE) and the volume of right hippocampus, and between the total score on the visual verbal learning test and the volume of the right and left parahippocampal gyrus. Conclusions: These findings highlight different patterns of relationship between cognitive performance and volumes of medial temporal structures in depressed individuals and healthy elderly subjects. The direct correlation between delayed visual verbal memory recall scores with left parahippocampal volumes specifically in elderly depressed individuals provides support to the view that depression in elderly populations may be a risk factor for dementia. (C) 2009 Elsevier Inc. All rights reserved.
Resumo:
In addition to pain and neurovegetative symptoms, patients with severe forms of complex regional pain syndrome (CRPS) develop a broad range of symptoms, including sensory disturbances, motor impairment and dystonic posturing. While most patients respond to medical therapy, some are considered refractory and become surgical candidates. To date, the most commonly used surgical procedure for CRPS has been spinal cord stimulation. This therapy often leads to important analgesic effects, but no sensory or motor improvements. We report on 2 patients with pain related to CRPS and severe functional deficits treated with motor cortex stimulation (MCS) who not only had significant analgesic effects, but also improvements in sensory and motor symptoms. In the long term (27 and 36 months after surgery), visual analog scale pain scores were improved by 60-70% as compared to baseline. There was also a significant increase in the range of motion in the joints of the affected limbs and an improvement in allodynia, hyperpathia and hypoesthesia. Positron emission tomography scan in both subjects revealed that MCS influenced regions involved in the circuitry of pain. Copyright (C) 2011 S. Karger AG, Basel
Resumo:
Brain-derived neurotrophic factor (BDNF) is the most widely distributed neurotrophin in the CNS, where it plays several pivotal roles in synaptic plasticity and neuronal survival. As a consequence, BDNF has become a key target in the physiopathology of several neurological and psychiatric diseases. Recent studies have consistently reported altered levels of BDNF in the circulation (i.e., serum or plasma) of patients with major depression, bipolar disorder, Alzheimer`s disease, Huntington`s disease and Parkinson`s disease. Correlations between serum BDNF levels and affective, cognitive and motor symptoms have also been described. BDNF appears to be an unspecific biomarker of neuropsychiatric disorders characterized by neurodegenerative changes.
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There is increasing evidence of a reciprocal fronto-limbic network in the pathogenesis of mood disorders. Prior in vivo proton ((1)H) spectroscopy studies provide evidence of abnormal neurochemical levels in the cingulate and dorsolateral prefrontal cortex (DLPFC) of adult subjects with major depressive disorder (MOD). We examined whether similar abnormalities occur in children and adolescents with MDD. We collected two-dimensional multi-voxel in vivo 1H spectroscopy data at 1.5 Tesla to quantify levels of N-acetyl-aspartate (NAA), glycerolphosphocholine plus phosphocholine (GPC + PC), and phosphocreatine plus creatine (PCr + Cr) in the DLPFC, medial prefrontal cortex (MPFC), and anterior cingulate (AC) of children and adolescents aged 8-17 years with MDD (n = 16) compared with healthy control subjects (n = 38). Analysis of covariance with age and gender as covariates was performed. MDD subjects showed significantly lower levels of NAA in the right MPFC and right AC than controls. MDD subjects also had significantly lower levels of GPC + PC in the right AC than control subjects. There were no significant differences in other metabolites in the studied regions. Pediatric patients with MDD exhibit neurochemical alterations in prefrontal cortex regions that are important in the monitoring and regulation of emotional states. (C) 2010 Elsevier Ireland Ltd. All rights reserved.
Resumo:
The microtubule-associated protein Tau promotes the assembly and stability of microtubules in neuronal cells. Six Tau isoforms are expressed in adult human brain. All six isoforms become abnormally hyperphosphorylated and form neurofibrillary tangles in Alzheimer disease (AD) brains. In AD, reduced activity of phospholipase A(2) (PLA(2)), specifically of calcium-dependent cytosolic PLA(2) (cPLA(2)) and calcium-independent intracellular PLA(2) (iPLA(2)), was reported in the cerebral cortex and hippocampus, which positively correlated with the density of neurofibrillary tangles. We previously demonstrated that treatment of cultured neurons with a dual cPLA(2) and iPLA(2) inhibitor, methyl arachidonyl fluorophosphonate (MAFP), decreased total Tau levels and increased Tau phosphorylation at Ser(214) site. The aim of this study was to conduct a preliminary investigation into the effects of in vivo infusion of MAFP into rat brain on PLA(2) activity and total Tau levels in the postmortem frontal cortex and dorsal hippocampus. PLA(2) activity was measured by radioenzymatic assay and Tau levels were determined by Western blotting using the anti-Tau 6 isoforms antibody. MAFP significantly inhibited PLA(2) activity in the frontal cortex and hippocampus. The reactivity to the antibody revealed three Tau protein bands with apparent molecular weight of close to 40, 43 and 46 kDa in both brain areas. MAFP decreased the 46 kDa band intensity in the frontal cortex, and the 43 and 46 kDa band intensities in the hippocampus. The results indicate that in vivo PLA(2) inhibition in rat brain decreases the levels of total (nonphosphorylated plus phosphorylated) Tau protein and corroborate our previous in vitro findings.
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Objectives: The absence of pathophysiologically relevant diagnostic markers of bipolar disorder (BD) leads to its frequent misdiagnosis as unipolar depression (UD). We aimed to determine whether whole brain white matter connectivity differentiated BD from UD depression. Methods: We employed a three-way analysis of covariance, covarying for age, to examine whole brain fractional anisotropy (FA), and corresponding longitudinal and radial diffusivity, in currently depressed adults: 15 with BD-type I (mean age 36.3 years, SD 12.0 years), 16 with recurrent UD (mean age 32.3 years, SD 10.0 years), and 24 healthy control adults (HC) (mean age 29.5 years, SD 9.43 years). Depressed groups did not differ in depression severity, age of illness onset, and illness duration. Results: There was a main effect of group in left superior and inferior longitudinal fasciculi (SLF and ILF) (all F >= 9.8; p <= .05, corrected). Whole brain post hoc analyses (all t >= 4.2; p <= .05, corrected) revealed decreased FA in left SLF in BD, versus UD adults in inferior temporal cortex and, versus HC, in primary sensory cortex (associated with increased radial and decreased longitudinal diffusivity, respectively); and decreased FA in left ILF in UD adults versus HC. A main effect of group in right uncinate fasciculus (in orbitofrontal cortex) just failed to meet significance in all participants but was present in women. Post hoc analyses revealed decreased right uncinate fasciculus FA in all and in women, BD versus HC. Conclusions: White matter FA in left occipitotemporal and primary sensory regions supporting visuospatial and sensory processing differentiates BD from UD depression. Abnormally reduced FA in right fronto-temporal regions supporting mood regulation, might underlie. predisposition to depression in BD. These measures might help differentiate pathophysiologic processes of BD versus UD depression.
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Objectives. Abnormalities in neurotrophic systems have been reported in Alzheimer`s disease (AD), as shown by decreased serum brain-derived neurotrophic factor (BDNF) levels and association with BDNF genetic polymorphisms. In this study, we investigate whether these findings can be detected in patients with mild cognitive impairment (MCI), which is recognized as a high risk condition for AD. We also address the impact of these variables on the progression of cognitive deficits within the MCI-AD continuum. Methods. One hundred and sixty older adults with varying degrees of cognitive impairment (30 patients with AD, 71 with MCI, and 59 healthy controls) were longitudinally assessed for up to 60 months. Baseline serum BDNF levels were determined by sandwich ELISA, and the presence of polymorphisms of BDNF and apolipoprotein E (Val66Met and APOE*E4, respectively) was determined by allelic discrimination analysis on real time PCR. Modifications of cognitive state were ascertained for non-demented subjects. Results. Mean serum BDNF levels were reduced in patients with MCI and AD, as compared to controls (509.2 +/- 210.5; 581.9 +/- 379.4; and 777.5 +/- 467.8 pg/l respectively; P < 0.001). Baseline serum BDNF levels were not associated with the progression of cognitive impairment upon follow-up in patients with MCI (progressive MCI, 750.8 +/- 463.0; stable MCI, 724.0 +/- 343.4; P = 0.8), nor with the conversion to AD. Although Val66Met polymorphisms were not associated with the cross-sectional diagnoses of MCI or AD, the presence of Met-BDNF allele was associated with a higher risk of disease-progression in patients with MCI (OR = 3.0 CI(95%) [1.2-7.8], P = 0.02). We also found a significant interaction between the APOE*E4 and Met-BDNF allele increasing the risk of progression of cognitive impairment in MCI patients (OR = 4.4 CI(95%) [1.6-12.1], P = 0.004). Conclusion. Decreased neurotrophic support, as indicated by a reduced systemic availability of BDNF, may play role in the neurodegenerative processes that underlie the continuum from MCI to AD. The presence of Met-BDNF allele, particularly in association with APOE*E4, may predict a worse cognitive outcome in patients with MCI.
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Objective: We aimed to investigate the efficacy of 20 Hz repetitive transcranial magnetic stimulation (rTMS) of either right or left dorsolateral prefrontal cortex (DLPFC) as compared to sham rTMS for the relief of posttraumatic stress disorder (PTSD)-associated symptoms. Method: In this double-blind, placebo-controlled phase II trial conducted between October 2005 and July 2008, 30 patients with DSM-IV-diagnosed PTSD were randomly assigned to receive 1 of the following treatments: active 20 Hz rTMS of the right DLPFC, active 20 Hz rTMS of the left DLPFC, or sham rTMS. Treatments were administered in 10 daily sessions over 2 weeks. A blinded rater assessed severity of core PTSD symptoms, depression, and anxiety before, during, and after completion of the treatment protocol. In addition, a battery of neuropsychological tests was measured before and after treatment. Results: Results show that both active conditions-20 Hz rTMS of left and right DLPFC induced a significant decrease in PTSD symptoms as indexed by the PTSD Checklist and Treatment Outcome PTSD Scale; however, right rTMS induced a larger effect as compared to left rTMS. In addition, there was a significant improvement of mood after left rTMS and a significant reduction of anxiety following right rTMS. Improvements in PTSD symptoms were long lasting; effects were still significant at the 3-month follow-up. Finally, neuropsychological evaluation showed that active 20 Hz rTMS is not associated with cognitive worsening and is safe for use in patients with PTSD. Conclusions: These results support the notion that modulation of prefrontal cortex can alleviate the core symptoms of PTSD and suggest that high-frequency rTMS of right DLPFC might be the optimal treatment strategy. J an Psychiatry 2010;71(8):992-999 (C) Copyright 2009 Physicians Postgraduate Press, Inc.
Resumo:
Emotional liability and mood dysregulation characterize bipolar disorder (BID), yet no study has examined effective connectivity between parahippocampal gyrus and prefrontal cortical regions in ventromedial and dorsal/lateral neural systems subserving mood regulation in BD. Participants comprised 46 individuals (age range: 18-56 years): 21 with a DSM-IV diagnosis of BID, type I currently remitted; and 25 age- and gender-matched healthy controls (HC). Participants performed an event-related functional magnetic resonance imaging paradigm, viewing mild and intense happy and neutral faces. We employed dynamic causal modeling (I)CM) to identify significant alterations in effective connectivity between BD and HC. Bayes model selection was used to determine the best model. The right parahippocampal gyrus (PHG) and right subgenual cingulate gyrus (sgCG) were included as representative regions of the ventromedial neural system. The right dorsolateral prefrontal cortex (DLPFC) region was included as representative of the dorsal/lateral neural system. Right PHG-sgCG effective connectivity was significantly greater in BD than HC, reflecting more rapid, forward PHG-sgCG signaling in BD than HC. There was no between-group difference in sgCG-DLPFC effective connectivity. In BD, abnormally increased right PHG-sgCG effective connectivity and reduced right PHG activity to emotional stimuli suggest a dysfunctional ventromedial neural system implicated in early stimulus appraisal, encoding and automatic regulation of emotion that may represent a pathophysiological functional neural mechanism for mood dysregulation in BD. (C) 2009 Elsevier Ireland Ltd. All rights reserved.
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INTRODUCTION: Penetrating injury of the skull and brain is relatively uncommon, representing about 0.4% of head injuries. In this paper the Authors describe a case of patient victim of transorbital stab with brain injury with good recovery and review the literature about cranial stab wound. CASE REPORT: A 23-year-old man was involved in an altercation which resulted in the patient sustaining wounds to the head, with penetrating in left transorbital, affecting the eye. At arrival to the first trauma center the patient was conscient and complete responsive with 15 points in Glasgow Coma Scale, and motor deficit grade III. CT scan demonstrated left periventricular brain hematoma and supraorbital fracture. A four-vessel cerebral angiogram demonstrated no anormality. In this evolution patient presented good neurologic outcome. CONCLUSION: In patients conscients with no surgical lesion like our patient, the hospital discharge must occurr after the angiogram have excluded intracranial vascular lesion.