May
24
2009
0

Berberine reduces the hypoxic-ischemic insult in rat pup brain.

Berberine, an isoquinoline alkaloid extracted from medicinal herbs, has been used as antipyretic, antidiarrheal, bactericide and anti-inflammatory agent. In this study, berberine effects on neuronal damage have been examined. The right carotid artery of seven-day-old rat pups was ligated (ischemic insult), then berberine solution (0.2, 0.5, 1 or 2 mg/kg) was injected intra-peritoneally, and 30 minutes later pups were passed through hypoxic condition with breathing in air containing 10% oxygen and 90% nitrogen(hypoxic insult). The day after that the brains of pups were enucleated for pathologic assessment. Pathologic review of the samples obtained from rats treated with different doses of berberine in comparison with samples from pups treated by normal saline showed that there was a significant reduction of brain injury and edema in the rats treated with berberine. Our study also demonstrates that berberine reduces brain ischemic-hypoxic injury dose-dependently. Therefore, beberine may be considered as useful anti-stroke agent.

Written by admin in: Brain Damage |
May
24
2009
0

Mitochondrial cholesterol loading exacerbates amyloid beta peptide-induced inflammation and neurotoxicity.

The role of cholesterol in Alzheimer’s disease (AD) has been linked to the generation of toxic amyloid beta peptides (Abeta). Using genetic mouse models of cholesterol loading, we examined whether mitochondrial cholesterol regulates Abeta neurotoxicity and AD pathology. Isolated mitochondria from brain or cortical neurons of transgenic mice overexpressing SREBP-2 (sterol regulatory element binding protein 2) or NPC1 (Niemann-Pick type C1) knock-out mice exhibited mitochondrial cholesterol accumulation, mitochondrial glutathione (mGSH) depletion and increased susceptibility to Abeta1-42-induced oxidative stress and release of apoptogenic proteins. Similar findings were observed in pharmacologically GSH-restricted rat brain mitochondria, while selective mGSH depletion sensitized human neuronal and glial cell lines to Abeta1-42-mediated cell death. Intracerebroventricular human Abeta delivery colocalized with mitochondria resulting in oxidative stress, neuroinflammation and neuronal damage that were enhanced in Tg-SREBP-2 mice and prevented upon mGSH recovery by GSH ethyl ester coinfusion, with a similar protection observed by intraperitoneal administration of GSH ethyl ester. Finally, APP/PS1 (amyloid precursor protein/presenilin 1) mice, a transgenic AD mouse model, exhibited mitochondrial cholesterol loading and mGSH depletion. Thus, mitochondrial cholesterol accumulation emerges as a novel pathogenic factor in AD by modulating Abeta toxicity via mGSH regulation; strategies boosting the particular pool of mGSH may be of relevance to slow down disease progression.

Written by admin in: Brain Damage |
May
24
2009
0

Neuroendocrine Function following Traumatic Brain Injury and Subsequent Intensive Care Treatment: A Prospective Longitudinal Evaluation.

Abstract Neuroendocrine dysfunction following traumatic brain injury (TBI) has been described extensively. However, few studies are longitudinal and most lack subtle radiological, clinical, and repetitive endocrine assessment in the acute phase. Accordingly, we prospectively assessed neuroendocrine function in 71 patients after TBI. Injury was documented by a computed tomography (CT). During the first week, critical clinical data (Glasgow Coma Score, APACHE score), treatment variables such as duration of analgosedation for mechanical ventilation, were related to basal pituitary function. More than 2 years later, a subgroup of patients was re-evaluated using dynamic testing with ACTH and GHRH-arginine tests. The Pearson's correlation analysis and Mann-Whitney rank sum test for group differences were used for statistical analysis. None of the CT findings predicted neuroendocrine dysfunction following TBI. The adaptive response to critical illness with significantly elevated cortisol levels on admission and decreased levels thereafter in patients ventilated for more than 24 h (p < 0.05) was attenuated following severe TBI (p < 0.05). However, the coincidence of low serum cortisol and increased urinary excretion of glucocorticoid metabolites in about 80% of patients challenges the relevance of basal hormone measurements. In ventilated patients, total T3 and free T4 were decreased (p < 0.05), TSH was low on day 3 (p < 0.05), and a gonadotropic insufficiency was present (p < 0.05). The thyrotropic and gonadotropic system recovered completely within the follow-up period. With regard to the somatotropic system, neither brain injury severity nor mechanical ventilation was associated with an insufficiency during the acute phase post-injury. However, initially low GH levels predicted a persistent deficiency (r = 0.731, p < 0.001). We conclude that both severe TBI and prolonged mechanical ventilation result in hormonal disturbances early after injury, suggesting a pathophysiological response to brain injury and subsequent intensive care treatment rather than morphological damage.

Written by admin in: Brain Damage |
May
24
2009
0

Adiponectin protects hippocampal neurons against kainic acid-induced excitotoxicity.

Neuronal damage after seizure is correlated with blood-brain barrier (BBB) leakage. Adiponectin (Ad) has shown protective effects on endothelial function. In this study, we investigated the effects of Ad on cell survival and BBB integrity in the mouse hippocampus after kainic acid (KA) treatment. Twenty four hours after intracerebroventricular injection of recombinant Ad, mice were treated with KA, and then sacrificed 48 hrs later. Decreased serum Ad and increased hippocampal Ad receptor 1 in the hippocampus of KA-treated mice were prevented by Ad pretreatment. Using cresyl violet staining, TUNEL analysis, and immunostaining for caspase-3, histological evaluation revealed that the marked cell death noted in the hippocampus of KA-treated mice was not observed in KA-treated mice pretreated with Ad. Impairment of the BBB, which was demonstrated by the presence of IgG, was inhibited by Ad pretreatment. Immunohistochemical analysis indicated that KA caused up-regulation of hippocampal VEGF, eNOS, and NF-kappaB levels, all of which were reduced in animals that received Ad pretreatment. These data indicate that Ad preserves the integrity of the BBB and has neuroprotective effects in an animal model of seizures.

Written by admin in: Brain Damage |
May
24
2009
0

Defining Meyer’s loop-temporal lobe resections, visual field deficits and diffusion tensor tractography.

Anterior temporal lobe resection is often complicated by superior quadrantic visual field deficits (VFDs). In some cases this can be severe enough to prohibit driving, even if a patient is free of seizures. These deficits are caused by damage to Meyer’s loop of the optic radiation, which shows considerable heterogeneity in its anterior extent. This structure cannot be distinguished using clinical magnetic resonance imaging sequences. Diffusion tensor tractography is an advanced magnetic resonance imaging technique that enables the parcellation of white matter. Using seed voxels antero-lateral to the lateral geniculate nucleus, we applied this technique to 20 control subjects, and 21 postoperative patients. All patients had visual fields assessed with Goldmann perimetry at least three months after surgery. We measured the distance from the tip of Meyer’s loop to the temporal pole and horn in all subjects. In addition, we measured the size of temporal lobe resection using postoperative T(1)-weighted images, and quantified VFDs. Nine patients suffered VFDs ranging from 22% to 87% of the contralateral superior quadrant. In patients, the range of distance from the tip of Meyer’s loop to the temporal pole was 24-43 mm (mean 34 mm), and the range of distance from the tip of Meyer’s loop to the temporal horn was -15 to +9 mm (mean 0 mm). In controls the range of distance from the tip of Meyer’s loop to the temporal pole was 24-47 mm (mean 35 mm), and the range of distance from the tip of Meyer’s loop to the temporal horn was -11 to +9 mm (mean 0 mm). Both quantitative and qualitative results were in accord with recent dissections of cadaveric brains, and analysis of postoperative VFDs and resection volumes. By applying a linear regression analysis we showed that both distance from the tip of Meyer’s loop to the temporal pole and the size of resection were significant predictors of the postoperative VFDs. We conclude that there is considerable variation in the anterior extent of Meyer’s loop. In view of this, diffusion tensor tractography of the optic radiation is a potentially useful method to assess an individual patient’s risk of postoperative VFDs following anterior temporal lobe resection.

Written by admin in: Brain Damage |
May
24
2009
0

Improvement After Constraint-Induced Movement Therapy Is Independent of Infarct Location in Chronic Stroke Patients.

BACKGROUND AND PURPOSE: Disruption of the corticospinal tract at various locations in the brain has been shown to predict worse spontaneous motor recovery after stroke. However, the anatomic specificity of previous findings was limited by the categorical classification of infarct locations. Here we used computational methods to more precisely determine the specific anatomic locations associated with impaired motor ability. More important, however, our study also used these techniques to evaluate whether infarct location could influence motor outcomes after Constraint-Induced Movement therapy (CI therapy), a specific and controlled form of physical therapy. METHODS: Quantitative voxel-based analyses were used to determine whether infarct location could predict either initial motor ability or clinical improvement after CI therapy in chronic stroke patients. RESULTS: Although corona radiata infarcts were associated with worse in-laboratory motor ability at pretreatment, infarct location did not predict improvement in either the laboratory or the life situation after CI therapy. CONCLUSIONS: The extent of improvement from CI therapy does not depend on the location of neurological damage, despite there being a pretreatment relationship between infarct location and in-laboratory motor ability. This dissociation could be explained by brain plasticity induced by CI therapy.

Written by admin in: Brain Damage |
May
24
2009
0

Location of the Mandibular Canal and the Topography of Its Neurovascular Structures.

The major complication in dental implant surgery is loss of sensation due to damage to the inferior alveolar nerve resulting from poor characterization of the location of the mandibular canal and the traveling course of the inferior alveolar nerve, artery, and vein therein. The purposes of this study were to determine the buccolingual location of the mandibular canal and to verify the topography of the inferior alveolar nerve, artery, and vein therein by three-dimensional reconstruction of these structures. Sixty-two mandible sides were used for this study. The buccolingual location of the mandibular canal was classified into 3 types: type 1 (70%), where the canal follows the lingual cortical plate at the mandibular ramus and body; type 2 (15%), where the canal follows the middle of the ramus behind the second molar and the lingual plate passing through the second and first molars; and type 3 (15%), where the canal follows the middle or the lingual one third of the mandible from the ramus to the body. Three-dimensional reconstruction of the mandibular canal revealed that the inferior alveolar vessel traveled above the inferior alveolar nerve in 8 cases (80%), with the inferior alveolar artery being lingual to the inferior alveolar vein, and in 2 cases (20%) where the inferior alveolar vessel was buccal to the nerve.

Written by admin in: Brain Damage |
May
24
2009
0

Factors affecting leisure participation after a traumatic brain injury: an exploratory study.

OBJECTIVE: To explore leisure participation by people with traumatic brain injury (TBI) and reasons underlying changes after the trauma. PARTICIPANTS: Twenty-six individuals with mild to severe TBI. MAIN MEASURE: Leisure Profile, a semi-structured questionnaire measuring involvement in leisure activities before and after TBI (frequency of activities, degree of interest, and desire to modify one’s leisure activities), attitudes toward leisure, and difficulties that might influence leisure activities (impairments and environmental obstacles). RESULTS: Leisure participation was greatly disrupted after TBI, with 92% of the participants reporting a reduction posttrauma. Less severe injuries, more time since the injury, and the presence of social obstacles in the environment were positively correlated with leisure participation. Motor impairments had a negative impact on leisure participation. CONCLUSION: TBI has a significant negative effect on leisure participation. Leisure activities should be evaluated and included in a therapy program designed to promote reintegration into society and work.

Written by admin in: Brain Damage |
May
24
2009
0

OmpA Is the Critical Component for Escherichia coli Invasion-Induced Astrocyte Activation.

Escherichia coli is the major Gram-negative bacterial pathogen in neonatal meningitis. Outer membrane protein A (OmpA) is a conserved major protein in the E. coli outer membrane and is involved in several host-cell interactions. To characterize the role of OmpA in the invasion of astrocytes by E. coli, we investigated OmpA-positive and OmpA-negative E. coli strains. Outer membrane protein A E44, E105, and E109 strains adhered to and invaded C6 glioma cells 10- to 15-fold more efficiently than OmpA-negative strains. Actin rearrangement, protein tyrosine kinase, and phosphoinositide 3-kinase activation were required for OmpA-mediated invasion by E. coli. In vitro infection of C6 cells and intracerebral injection into mice of the E44 strain induced expression of the astrocyte differentiation marker glial fibrillary acidic protein and the inflammatory mediators cyclooxygenase 2 and nitric oxide synthase 2. After intracerebral infection with E44, all C57BL/6 mice died within 36hours, whereas 80% of mice injected with E44 premixed with recombinant OmpA protein survived. Astrocyte activation and neutrophil infiltration were reduced in brain tissue sections in the mice given OmpA. Taken together, these data suggest that OmpA-mediated invasion plays an important role in the early stage of E.coli-induced brain damage, and that it may have therapeutic use in E. coli meningitis.

Written by admin in: Brain Damage |
May
21
2009
0

Skull bone flap fixation–comparative experimental study to assess the reliability of a new grip-like titanium device (Skull Grip) versus traditional sutures: technical note.

INTRODUCTION: After completing a craniotomy, whenever possible, it is crucial to replace and fix the removed bone flap to the cranium; this in order to keep the brain’s protection as well as for cosmetic purposes. Visible skull defects might cause patients psychosocial problems and, most importantly, expose the brain to accidental damage. A fixation device should not only provide optimal attachment of the flap to the skull but also allow fast bony healing to avoid possible pseudoarthrosis and/or osteolytic changes. METHODS: After performing 12 different craniotomies on 4 human cadaver heads the skull flaps were replaced using traditional sutures and a new skull fixation device; for each fixation technique a load-bearing test was performed and the results compared. RESULTS: Bone flaps fixed with the “Skull Grip” showed a strong fixation with optimal plastic deformation when compared to flaps held by sutures that showed less resistance to pressure and could be easily dislocated. CONCLUSION: The “Skull Grip” has shown to be a reliable, effective, and stronger bone flap fixation superior to suturing technique.

Written by admin in: Brain Damage |

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