Jun
22
2010
0

Impaired mimicry response to angry faces following severe traumatic brain injury.

This study examined whether severe traumatic brain injuries (TBIs) interfere with normal facial mimicry when observing facial expressions. A total of 21 adults with severe TBI and 20 control participants viewed angry and happy facial expressions taken from the Ekman and Friesen (1976) series while facial movement of the corrugator supercilii (brow) and zygomaticus major (cheek) was monitored. Faces were presented both statically and dynamically (gradually morphing from neutral to the final expression). The control group showed increased brow activity to angry expressions and increased cheek activity to happy expressions. This activity was evident as early as 500 ms, consistent with previous research suggesting that facial mimicry commences as an automatic process. The TBI group showed similar activity to happy expressions but no clear response to angry expressions, either early (500-1,000 ms) or over the entire 6-s duration of the displayed image. This was the case for both static and dynamic displays. There was no relationship between facial mimicry and accuracy in identifying (matching) facial expressions for either the TBI or control participants. These results are consistent with the view that ventral frontal structures mediate early responses to angry expressions and that these are frequently compromised as a result of severe TBI. The results did not support the view that simulation (mimicry) facilitates emotion recognition.

Written by admin in: Brain Damage |
Jun
22
2010
0

Hypopituitarism following brain injury: when does it occur and how best to test?

Aim of this review is to highlight how and when Traumatic Brain Injury (TBI) as well as Subarachnoid Haemorrhage (SAH) and primary Brain Tumours (pBT) of the Central Nervous System (CNS) can induce hypopituitarism, an under-diagnosed clinical problem. Moreover, this review aims to clarify, on the basis of the recent evidences, how these patients have to be tested for pituitary-function. Both retrospective and prospective studies recommended that patients with more severe form of Brain Injuries (BI) and in particular, those with fractures of the base of the skull or early diabetes insipidus, have to be closely monitored for signs and symptoms of endocrine dysfunction. Further studies will be crucial to raise awareness and remind physicians on the prevalence of hypopituitarism in patients with BI and to elucidate any incremental benefits these patients may receive from hormone replacement.

Written by admin in: Brain Damage |
Jun
22
2010
0

Time Varying Neonatal Seizure Localization.

Background: A common cause for damage to the neonatal brain is a shortage in the oxygen supply to the brain or asphyxia. Neonatal seizures are the most frequent manifestation of neonatal neurologic disorders. Multichannel EEG recordings allow topographic localization of seizure foci. Objectives: We want to objectively determine the spatial distribution of the seizure on the scalp, the location in time and order the dominant sources in the brain based on their strength. Methods: In this paper we combine a method based on higher order CP-decomposition with subsequent singular value decomposition (SVD). Results: We illustrate the abilities of the method on simulated as well as on real neonatal seizure EEG. Conclusions: The proposed method provides reliable time and spatial information about the seizure, gives a clear overview of what is going on in the EEG and allows easy interpretation.

Written by admin in: Brain Damage |
Jun
22
2010
0

[Disruptive nocturnal behavior in elderly subjects: could it be a parasomnia?]

Parasomnias are sleep-related abnormal behaviors. They are frequent and overlooked causes of nocturnal disruptive behavior in the elderly, especially when patients are cognitively impaired. Confusion and violence can result in sleep disruption, injuries for the patients or their bed partners, caregivers distress, and they can be a motive for institutionalization. Parasomnias include the NonREM sleep disorders of arousal (sleepwalking, sleep terrors, confusional arousals and sleep-related eating disorder), the REM sleep behavior disorder (RBD) and more rarely the parasomnia overlap syndrome, which associates both NREM and REM parasomnias. Patients with NREM sleep parasomnias are confused, eyes open, with a glazed look during their nocturnal behaviors, and they have a post-episode amnesia. They shout and bolt from the bed (night terrors), look about in a confused manner, walk and speak (sleepwalking), and eat peculiar or inedible food (sleep-related eating disorders). These behaviors, which are frequent in young adults, may be triggered by short-half live hypnotics in elderly. During the parasomnia, the brain is partially awake (enough to perform complex motor and verbal action), and partially asleep (without conscious awareness or responsibility). RBD is characterized by a loss of the normal muscle atonia that accompanies REM sleep. Patients have excessive motor activity such as punching, kicking, or crying out in association with dream content. RBD are frequent in Parkinson’s disease and dementia with Lewy bodies and may precede the cognitive or motor symptoms of these diseases by 5 to 10 years. RBD can also be promoted by antidepressants. When combined with thorough clinical interviews, the video-polysomnography is a powerful tool, especially for discriminating the parasomnia from nocturnal frontal lobe epilepsy, sleep apneas and periodic leg movements. Ensuring safety and withdrawing deleterious treatments are useful in patients with violent activities, potential injurious or bothersome to other household members. Clonazepam and melatonin (3-12 mg) are highly effective for treating RBD.

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Jun
22
2010
0

MRI and X-ray scanning images of the brain of 3,6 and 9 months old rats with bilateral neonatal ventral hippocampus lesions.

Rats with bilateral neonatal ventral hippocampus lesions (NVHL) are commonly used for modeling developmental aspects of the pathophysiology of schizophrenia. Given that functional changes become significant only after puberty, NVHL as well as sham operated rats were analyzed at the ages of 21, 42 and 63days (i.e. as pups, adolescents and adults), using MRI to examine the damage caused by surgery over time. Morphometric evaluations were considered and lesions were classified as small, medium and large. The volume of lesions increased regularly with age, to a greater extent than increases in overall brain size. This was relatively linear, corresponding to a gradually shrinking forebrain, and these observations held true for each class of lesions considered. Following the observation that the lesion procedure elicited calcifications in the brain, the same rats were subjected to 3D X-ray scanning the day after each MRI session, allowing precise measurements of skull size to be carried out. The NVHL rats had smaller skulls, however the dimensions of the calcifications did not grow more than the skull size over time. The mechanisms underlying the progressive anatomical changes following surgery are discussed. and we propose this in vivo follow-up method to investigate therapeutic strategies aimed at countering or limiting the post-lesion consequences of a neonatal brain damage. Copyright © 2010. Published by Elsevier Inc.

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Jun
22
2010
0

Decreased expression of spine-associated Rap guanosine triphosphatase-activating protein (SPAR) in glutamate-treated primary hippocampal neurons.

Spine-associated Rap guanosine triphosphatase-activating protein (SPAR) is an important regulator of activity-dependent remodeling of synapses. It is also critically involved in both mature dendritic spine formation and the maintenance of spine maturity. Glutamate is a major neurotransmitter of the brain, and is involved in all aspects of cognitive function, as it is the primary transmitter utilized by the cortical and hippocampal pyramidal neurons. Glutamate has also been associated with neuronal dendritic spine damage. The precise molecular mechanisms underlying dendritic spine damage following glutamate-induced neurotoxicity remain unknown. In the current study, we measured mRNA and protein expression levels of SPAR and serum-inducible kinase (SNK) in primary hippocampal neurons following glutamate treatment. Expression of SPAR and SNK was altered by glutamate treatment, indicating that the SPAR and SNK signaling pathways may be involved in the damage to dendritic spines in hippocampal neurons following excitotoxicity induced by glutamate. Copyright © 2010 Elsevier Ltd. All rights reserved.

Written by admin in: Brain Damage |
Jun
22
2010
0

Efficacy and safety of immunization with phosphorylated-tau against neurofibrillary-tangles in mice.

As an abnormally folded and aggregated protein, tau composed of neurofibrillary-tangles (NFTs) in Alzheimer’s-disease and other tauopathies- seems to be a candidate for immunotherapy. Yet, the encephalitogenicity of full-length tau protein, recently reported by us in immunized mice, demands to carefully and selectively target pathological tau and address both efficacy (anti-NFT effect) and safety (free of encephalitis). We immunized NFT-mice with NFT-related phosphorylated (phos)-tau peptides, using an immunization protocol aimed to predispose a proinflammatory milieu in CNS as a set up to detect biohazard, an approach we used when the neurotoxicity of full length tau was detected [use of complete Freund adjuvant (CFA) with pertussis-toxin (PT)]. A decrease of about 40% in NFT-burden in CNS was demonstrated and was accompanied with an increase in microglial burden. Anti-phos-tau antibodies were detected in serum and blood vessels in the CNS, while no encephalitogenicity (free of clinical neurological deficits, of adverse effects on brain inflammatory cells and of axonal damage) was recorded. The level of the lysosomal proteases, cathepsin D and L, were affected in the immunized mice suggesting the possible involvement of the lysosomal system in the decrease of NFTs. The robust anti-NFT effect and lack of encephalitogenicity in NFT-mice immunized with phos-tau peptides, even-though CFA with PT was included in vaccine, point to their anti-NFT therapeutic potential. Copyright © 2010. Published by Elsevier Inc.

Written by admin in: Brain Damage |
Jun
22
2010
0

An angiotensin II type 1 receptor blocker can preserve endothelial function and attenuate brain ischemic damage in spontaneously hypertensive rats.

Hypertension reduces endothelial nitric oxide synthase (eNOS) expression and leads to endothelial dysfunction. However, few studies have demonstrated the influences of hypertension on eNOS function in the cerebral cortex. The present study investigates the influences of hypertension on endothelial function in the cerebral cortex and the protective effects of antihypertensive agents against brain ischemia through the preservation of endothelial function. Five- and ten-week-old male Wistar rats and spontaneously hypertensive rats (SHR) were used for experiments. Five-week-old SHR received olmesartan, hydralazine, or vehicle for 5 weeks in drinking water. eNOS activation in the cerebral cortex was evaluated by analyzing levels of total and Ser(1177)-phosphorylated eNOS protein by Western blot. Blood pressure of 10-week-old SHR without treatment was clearly high, and the ratio of phospho-eNOS/total eNOS protein was significantly low. Five-week treatment with olmesartan or hydralazine suppressed the elevation of blood pressure and the reduction of phosphorylated eNOS-Ser(1177) in SHR, and olmesartan was more effective in maintaining phosphorylation of eNOS-Ser(1177) than hydralazine. To assess the contribution of eNOS to maintaining cerebral blood flow (CBF), we monitored CBF by laser-Doppler flowmetry after L-N(5)-(1-iminoethyl)ornithine (L-NIO) infusion. CBF response to L-NIO was preserved in olmesartan-treated SHR but not in hydralazine-treated SHR. Furthermore, infarct volume 48 hr after transient focal brain ischemia in olmesartan-treated SHR was significantly reduced compared with vehicle-treated SHR. These findings indicate that chronic prehypertensive treatment with olmesartan could attenuate brain ischemic injury through the maintenance of endothelial function in the cerebral cortex in SHR. (c) 2010 Wiley-Liss, Inc.

Written by admin in: Brain Damage |
Jun
22
2010
0

Chronic caloric restriction reduces tissue damage and improves spatial memory in a rat model of traumatic brain injury.

Although it has been known for some time that chronic caloric or dietary restriction reduces the risk of neurodegenerative disorders and injury following ischemia, the possible role of chronic restriction in improving outcomes after traumatic brain injury (TBI) has not been previously studied. Therefore, 2-month-old male Sprague-Dawley rats were divided into two dietary groups, an ad libitum fed group (AL) and a caloric-restriction group (CR) that was provided with 70% of the food intake of AL rats (n = 10/group). After 4 months, a weight-drop device (300 g) was used to produce a 2-mm bilateral medial frontal cortex contusion following craniotomy. Additional animals in each dietary group (n = 10) were used as sham-operated controls. The CR diet resulted in body weights that were reduced by 30% compared with AL controls. Not only did CR decrease the size of the cortical lesion after injury, there were marked improvements in spatial memory as measured by Morris water maze that included an increase in the number of animals successfully finding the platform as well as significantly reduced time to finding the hidden platform. Western analysis, used to examine the expression of proteins that play a role in neuronal survival, revealed significant increases in brain-derived neurotrophic factor (BDNF) in the cortical region around the site of injury and in the hippocampus in CR rats after injury. These findings suggest that molecular mechanisms involved in cell survival may play a role in reducing tissue damage and improving cognition after TBI and that these mechanisms can be regulated by dietary interventions. (c) 2010 Wiley-Liss, Inc.

Written by admin in: Brain Damage |
Jun
22
2010
0

Folate and cancer: how DNA damage, repair and methylation impact on colon carcinogenesis.

Inappropriate diet may contribute to one third of cancer deaths. Folates, a group of water-soluble B vitamins present in high concentrations in green, leafy vegetables, maintain DNA stability through their ability to donate one-carbon units for cellular metabolism. Folate deficiency has been implicated in the development of several cancers, including cancer of the colorectum, breast, ovary, pancreas, brain, lung and cervix. Generally, data from the majority of human studies suggest that people who habitually consume the highest level of folate, or with the highest blood folate concentrations, have a significantly reduced risk of developing colon polyps or cancer. However, an entirely protective role for folate against carcinogenesis has been questioned, and recent data indicate that an excessive intake of synthetic folic acid (from high-dose supplements or fortified foods) may increase human cancers by accelerating growth of precancerous lesions. Nonetheless, on balance, evidence from the majority of human studies indicates that dietary folate is genoprotective against colon cancer. Suboptimal folate status in humans is widespread. Folate maintains genomic stability by regulating DNA biosynthesis, repair and methylation. Folate deficiency induces and accelerates carcinogenesis by perturbing each of these processes. This review presents recent evidence describing how these mechanisms act, and interact, to modify colon cancer risk.

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