Aug
17
2009
0

Stimulation of AT2 receptor exerts beneficial effects in stroke-prone rats: focus on renal damage.

BACKGROUND AND AIM: Angiotensin II acts through two major receptors: AT1-R and AT2-R. It is known that the stimulation of AT1-R mediates vasoconstriction, cell proliferation and fibrosis, aldosterone release and inflammatory response but, although the stimulation of AT2-R is thought to promote vasodilation and anti-inflammatory effects, its real in-vivo functions are still unclear. The aim of this study was to investigate the effects of specific and selective AT2-R stimulation on the pathological events occurring in spontaneously hypertensive stroke-prone rats (SHRSPs). METHODS AND RESULTS: SHRSPs who were fed a high-salt diet underwent long-term treatment with vehicle or compound 21 (C21), a nonpeptide selective AT2-R agonist, at doses of 0.75, 5 and 10 mg/kg per day. The vehicle-treated rats developed brain abnormalities detectable by magnetic resonance imaging after 42.5 +/- 7.5 days, and died 43 +/- 9.5 days after the start of the dietary treatment. The highest C21 dose delayed the occurrence of brain damage (P < 0.001 vs. vehicle-treated SHRSPs) and prolonged survival (P < 0.001) without affecting blood pressure. These beneficial effects of C21 were abolished by the administration of PD123319, an AT2-R antagonist. C21 treatment preserved renal structure by preventing inflammatory cell infiltration, collagen accumulation, and the neo-expression of vimentin; it also prevented the increased plasma renin activity and accumulation of urinary acute-phase proteins observed in the vehicle-treated rats. CONCLUSION: Specific and selective AT2-R stimulation has beneficial effects on the pathological events occurring in SHRSPs. These data indicate a new avenue for the pharmacological treatment of diseases in which modulation of the renin-angiotensin system is required.

Written by admin in: Brain Damage |
Aug
16
2009
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[Evaluation of voluntary movement organization in the late residual stage of cerebral palsy.]

The functional state of agonists and antagonists involving in providing of supporting function of feet and walking in adolescences, aged 13-15 years, with cerebral palsy has been studied using electromyography and polymyography. The electromyographical examination showed infringements of reciprocal innervation and potentials of fasciculation on the curves received from resting muscles of symmetric extremities. Polymyographic curves revealed the elongation of latent time of muscle tension and full period of relaxation against a background of expressed amplitude decay of the dynamometer card. Results obtained are thought to facilitate the more effective implementation of different rehabilitative measures in the late residual disease stage.

Written by admin in: Cerebral Palsy |
Aug
16
2009
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SNAP-II and SNAPPE-II and the Risk of Structural and Functional Brain Disorders in Extremely Low Gestational Age Newborns: The ELGAN Study.

Background: Illness severity measures predict death and illnesses in the newborn. It is unknown how well they predict brain lesions evident on ultrasound scans or neurodevelopmental dysfunctions in preterm infants. Methods: A total of 1,399 inborn infants born before the 28th week of gestation were given Scores for Neonatal Acute Physiology (SNAP-II and SNAPPE-II) based on data collected within the first 12 h of admission to the intensive care unit and had a protocol brain ultrasound scan read independently by 2 sonologists. Of the surviving 1,149 infants, 1,014 (88%) had a neurologic examination at approximately 24 months post-term equivalent, and 975 (85%) had a Bayley Scales of Infant Development assessment. SNAP-II and SNAPPE-II were dichotomized at arbitrary cut-offs (30 for SNAP-II and 45 for SNAPPE-II), using the highest quartile and decile of the week of gestation as a cut-off, and at a Z score of >1 standard deviation from an external mean. Results: After adjustment for gestational age, high SNAP-II and SNAPPE-II scores predicted intraventricular hemorrhage, moderate/severe ventriculomegaly and echodense lesions in cerebral white matter. Only 2 SNAP-II extremes, the highest decile for gestational age and a Z score >1, also predicted echolucent lesions in the white matter. Neither SNAP-II nor SNAPPE-II predicted any statistically significant diagnosis of cerebral palsy. MDI and PDI scores <55 were consistently predicted by both high SNAP-II and SNAPPE-II, whereas scores in the 55-69 range were inconsistently predicted. High SNAP-II and SNAPPE-II inconsistently predicted a positive screen for autism spectrum disorder and small head circumference at 24 months. Conclusion: The physiologic instability in the first 12 post-natal hours identified by illness severity scores conveys information about the risks of brain damage and neurodevelopmental dysfunctions. This risk information might reflect postnatal characteristics in the causal chain. On the other hand, high SNAP scores might be indicators of immaturity and vulnerability. Copyright © 2009 S. Karger AG, Basel.

Written by admin in: Cerebral Palsy |
Aug
16
2009
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The collaborative construction of non-serious episodes of interaction by non-speaking children with cerebral palsy and their peers.

Inequality in communicative resources available to non-speaking children with cerebral palsy in comparison with their ‘naturally’ speaking co-participants has material consequences for the ways in which face-to-face interaction is organized. Analyses of interaction involving non-speaking children with physical disability and speaking adults has often interpreted the patterns of interaction observed as indicative of non-speaking children’s apparent passivity in interaction. Research concerned with these children’s interactions with their peers has shown evidence of non-speaking children’s active engagement in episodes of interaction characterized by, for example, shared laughter and heightened affect. The analysis presented here utilizes the principles and practices of Conversation Analysis (CA) to examine how non-speaking children with cerebral palsy and their peers bring about and organize episodes of non-serious interaction. In so doing the analysis reveals how non-speaking children are demonstrably active in developing the interaction as non-serious, and how both children collaborate in constituting the non-speaking child as playfully naughty.

Written by admin in: Cerebral Palsy |
Aug
16
2009
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Assessment of neuromuscular activation of the upper limbs in children with spastic hemiparetic cerebral palsy during a dynamical task.

This study compared the intensity, co-activity and frequency content of the electromyography (EMG) signals recorded bilaterally from six muscles of the upper limbs in children with spastic hemiparetic cerebral palsy (SHCP) and typically developing (TD) children during a bilateral movement. It was found that children with SHCP executed the bimanual circular movement with higher intensities of mean neuromuscular activity in both arms compared to TD children. Furthermore, the movement was performed with longer phases of concentric and eccentric activity in children with SHCP, indicating more co-activation, especially in the more impaired arm. The EMG signals yielded a higher mean power frequency in all the muscles of the more impaired arm and the wrist and elbow flexors of the less impaired arm, which was interpreted as a relatively higher contribution of type II muscle fibres compared to TD children. These observations suggest that in children with SHCP bimanual coordination requires higher neuromuscular activation in the muscles of both arms. Furthermore, SHCP also seems to involve structural changes to the muscle properties, which differ between arms.

Written by admin in: Cerebral Palsy |
Aug
16
2009
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Most very low birth weight subjects do well as adults.

AIM: To study health, quality of life, educational level and occupation in very low birth weight (VLBW) children in early adulthood and the relationship of the findings to neonatal risk factors and later handicap. METHODS: This is a prospective long-term follow-up study of a regional cohort of 20-year-old VLBW subjects (n = 77) of all surviving VLBW children (n = 86) and 69/86 term controls born in 1987-1988 in the south-east of Sweden. Postal questionnaires were used: 1. A study-specific form, 2. Medical Outcomes Study, Short Form (SF-36), 3. Sense of Coherence. RESULTS: VLBW subjects did not differ significantly from their controls in self-perceived health, use of tobacco, education, occupation and way of living, or scoring on SF-36 and Sense of Coherence. Sixteen had cerebral palsy, attention deficit hyperactivity disorder or isolated mental retardation, and these subjects differed significantly from controls on SF-36 in physical functioning and physical health score, but not on Sense of Coherence. VLBW subjects were significantly lighter and shorter than their controls. Extremely low birth weight (ELBW), bronchopulmonary dysplasia and intraventricular haemorrhage were significantly associated with poorer scores on physical function. CONCLUSION: The 20-year old VLBW subjects reported perceived health and managed transition to adulthood similar to controls. Handicapped subjects had poorer self-perceived physical function. ELBW and severe neonatal complications were associated with poorer self-perceived physical health.

Written by admin in: Cerebral Palsy |
Aug
16
2009
0

Karwinskia humboldtiana (buckthorn) fruit causes central nervous system damage during chronic intoxication in the rat.

Karwinskia humboldtiana fruit (Kh) causes a neurological disorder 3-4 weeks after ingestion, characterized by flaccid, symmetrical, ascending paralysis, similar to the Guillain-Barre syndrome. In this polyneuropathy the lesion (demyelization) in peripheral nerves has been described in several animal species, both in acute and in chronic intoxication. However, no reports exist about the presence of lesions in the Central Nervous System (CNS), in chronic intoxication. We considered it important to evaluate, with histological techniques, the possible presence of lesions in the brain, by using a model of chronic intoxication that reproduces the same stages present in the human intoxication, to better understanding of this pathological process. In our present work we fed the ground Kh fruit to Wistar rats and samples of brain, cerebellum, and pons were embedded in paraffin. Sections were stained with Hematoxylin & Eosin (HE) and special stains for nerve tissue. Histopathological changes were evaluated in the CNS through the different stages of the polyneuropathy and comparison to a control group. With this methodology, we found lesions in the motor pathway. This is the first report about the presence of neuronal damage caused by Kh in the Central Nervous System in chronic intoxication.

Written by admin in: Brain Damage |
Aug
16
2009
0

Oxidative Mechanisms of Brain Dysfunction During Sepsis.

Oxidative stress has drawn a lot of attention in the past few decades, since it has been reported to participate in the mechanism of many diseases. Therefore, it seemed to be a good rationale to aim oxidative stress on therapeutic research. Sepsis is a complex systemic syndrome characterized by an imbalance between pro- and anti-inflammatory responses to a pathogen; its pathophysiology is a dynamic process which involves components of the immune system, the coagulation pathway, parenchymal cells, and the endocrine and metabolic pathways. It is well characterized that oxidative stress plays a crucial role in sepsis development, but the relation between central nervous system dysfunction and oxidative stress during sepsis is not well understood. Thus, we here summarize the current knowledge on the role of free radicals in the development of brain dysfunction in sepsis focusing on oxidative damage and the redox control of brain inflammatory pathways.

Written by admin in: Brain Damage |
Aug
16
2009
0

Nuclear calcium signaling controls expression of a large gene pool: identification of a gene program for acquired neuroprotection induced by synaptic activity.

Synaptic activity can boost neuroprotection through a mechanism that requires synapse-to-nucleus communication and calcium signals in the cell nucleus. Here we show that in hippocampal neurons nuclear calcium is one of the most potent signals in neuronal gene expression. The induction or repression of 185 neuronal activity-regulated genes is dependent upon nuclear calcium signaling. The nuclear calcium-regulated gene pool contains a genomic program that mediates synaptic activity-induced, acquired neuroprotection. The core set of neuroprotective genes consists of 9 principal components, termed Activity-regulated Inhibitor of Death (AID) genes, and includes Atf3, Btg2, GADD45beta, GADD45gamma, Inhibin beta-A, Interferon activated gene 202B, Npas4, Nr4a1, and Serpinb2, which strongly promote survival of cultured hippocampal neurons. Several AID genes provide neuroprotection through a common process that renders mitochondria more resistant to cellular stress and toxic insults. Stereotaxic delivery of AID gene-expressing recombinant adeno-associated viruses to the hippocampus confers protection in vivo against seizure-induced brain damage. Thus, treatments that enhance nuclear calcium signaling or supplement AID genes represent novel therapies to combat neurodegenerative conditions and neuronal cell loss caused by synaptic dysfunction, which may be accompanied by a deregulation of calcium signal initiation and/or propagation to the cell nucleus.

Written by admin in: Brain Damage |
Aug
16
2009
0

Perfusion imaging of the right perisylvian neural network in acute spatial neglect.

Recent studies have suggested a tightly connected perisylvian neural network associated with spatial neglect. Here we investigated whether structural damage in one part of the network typically is accompanied with functional damage in other, structurally intact areas of this network. By combining normalized fluid-attenuated inversion-recovery (FLAIR) imaging, diffusion-weighted imaging (DWI), and perfusion-weighted imaging (PWI) we asked whether or not lesions centering on fronto-temporal regions co-occur with abnormal perfusion in structurally intact parietal cortex. With thresholds applied to delineate behaviourally relevant malperfusion of brain tissue, the analysis of normalized time-to-peak (TTP) and maximal signal reduction (MSR) perfusion maps did not reveal significant changes outside the area of structural damage. In particular, we found no abnormal perfusion in the structurally intact inferior parietal lobule (IPL) and/or the temporo-parietal junction (TPJ). The present results obtained in three consecutively admitted neglect patients with fronto-temporal lesions indicate that structural damage in one part of the right perisylvian network associated with spatial neglect does not necessarily require dysfunction by malperfusion in other, structurally intact parts of the network to provoke spatial neglect. The neural tissue in the fronto-temporal cortex appears to have an original role in processes of spatial orienting and exploration.

Written by admin in: Brain Damage |

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