• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 403
  • 73
  • 44
  • 33
  • 32
  • 31
  • 24
  • 22
  • 8
  • 5
  • 5
  • 2
  • 2
  • 2
  • 1
  • Tagged with
  • 997
  • 997
  • 725
  • 144
  • 111
  • 107
  • 106
  • 106
  • 101
  • 100
  • 91
  • 90
  • 74
  • 70
  • 65
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
131

Effects of Subconcussive Head Injury on Anxiety

Erb, Paige Madeline January 2015 (has links)
No description available.
132

Traumatic brain injury caregivers experiences : an exploratory study in the Western Cape

Broodryk, Mandi 12 1900 (has links)
Thesis (MA)-- Stellenbosch University, 2014. / ENGLISH ABSTRACT: Family caregivers play a large role in the lives of traumatic brain injury (TBI) survivors. This study explored the experiences of family members who care for TBI survivors in the Western Cape. Emphasis was placed on the challenges and resources that were associated with the caregiving role. A qualitative exploratory research design was implemented, whereby thematic analysis was utilised to examine the semi-structured interviews that were conducted with 12 female family caregivers of TBI survivors. Several challenges emerged, namely trauma, consequences of a TBI, responsibilities, lack of support, unawareness, financial burden, emotional challenges and coping. Several resources were also identified, namely the road to recovery, social support, financial resource and coping. These findings suggest that although caregivers who care for a family member who sustained a TBI face several challenges through the caregiving task, these individuals have a number of resources that help them to cope. Interventions that focus on psycho-education have been identified as an important need amongst the participants of this study. In addition, the need for support groups were highlighted as an important way in which many of the challenges that these caregivers experience could be addressed. Caregivers also expressed a need for more active involvement of health care professionals with regard to the provision of guidance, empathy and information. It seems as if the caregivers view the relationship between themselves and the health care professionals involved in the treatment of their family member who sustained a TBI as very important. It was however evident from the findings of this study that the caregivers are generally not satisfied with the quality of the interaction between the health care professionals and themselves. This study’s findings serve as a basis for future research studies on the experiences of family caregivers of TBI survivors in the Western Cape. / AFRIKAANSE OPSOMMING: Gesinsversorgers speel ’n groot rol in die lewens van oorlewendes van traumatiese breinbeserings (TBB). Hierdie studie het die ervaringe van gesinsversorgers van TBB-oorlewendes in die Wes-Kaap verken. Die fokus is op die uitdagings en hulpbronne wat geassosieer word met die versorgingsrol. ’n Kwalitatiewe ontwerp is geïmplementeer, waarby tematiese analise gebruik is om die semigestruktureerde onderhoude van 12 vroulike gesinsversorgers van TBB-oorlewendes te bestudeer. Verskeie uitdagings het na vore gekom, naamlik trauma, gevolge van TBB, verantwoordelikhede, gebrek aan ondersteuning, onbewustheid, finansiële las, emosionele uitdagings en hantering. Die hulpbronne wat geïdentifiseer is, het die pad na herstel, sosiale ondersteuning, finansiële hulpbron en hantering ingesluit. Intervensies wat fokus op psigo-opvoeding is geïndentifiseer as ’n belangrike behoefte onder die deelnemers aan die studie. Hierbenewens is ook ’n behoefte aan ondersteuningsgroepe uitgelig as ’n belangrike wyse om die vele uitdagings wat hierdie versorgers ervaar aan te pak. Die versorgers het ook ’n behoefte ervaar aan meer aktiewe betrokkenheid van gesondheidskundiges ten opsigte van die voorsiening van leiding, empatie en inligting. Dit blyk dat versorgers die verhouding tussen hulself en die gesondheidskundiges betrokke by hul gesinslid met die TBB as belangrik beskou. Desnietemin blyk dit duidelik uit die bevindinge van hierdie studie dat versorgers oor die algemeen nie tevrede is met die kwaliteit van die interaksie tussen die gesondheidskundiges en hulself nie. Die bevindinge van hierdie studie dien as basis vir toekomstige navorsing oor die ervaringe van gesinsversorgers van TBB-oorlewendes in the Wes-Kaap.
133

Trajectories of care and changing relationships : the experiences of adults with acquired brain injuries and their families

Dodson, Elizabeth Anne January 2003 (has links)
This PhD thesis explores issues around acquired brain injury, focusing particularly on changing relationships between patients and carers and the trajectories they follow from the point of injury or diagnosis as a reconstructed life unfolds. Patients are identified as having strategies of adaptation and carers as taking on levels of agency, both of which shift according to time, context and other complex interactions. Each impacts on the other to produce an internal dynamic, the functionality of which is explored. Issues of care delivery are also raised, including the effects of mismatched expectations and of sharing or restricting information. This research is qualitative and based on the principles of grounded theory. 62 interviews were conducted involving 82 people (52 patients and 30 carers) and additional evidence was gathered from professional records, media reports and personal diaries. Themes were developed that can be linked together to form a trajectory of care, inside of which there is a finely balanced ecology. It is proposed that this trajectory although developed around data from people with brain injury is also applicable to other chronic conditions.
134

Rod microglia: elongation, alignment, and coupling to form trains across the somatosensory cortex after experimental diffuse brain injury

Ziebell, Jenna, Taylor, Samuel, Cao, Tuoxin, Harrison, Jordan, Lifshitz, Jonathan January 2012 (has links)
BACKGROUND:Since their discovery, the morphology of microglia has been interpreted to mirror their function, with ramified microglia constantly surveying the micro-environment and rapidly activating when changes occur. In 1899, Franz Nissl discovered what we now recognize as a distinct microglial activation state, microglial rod cells (Stabchenzellen), which he observed adjacent to neurons. These rod-shaped microglia are typically found in human autopsy cases of paralysis of the insane, a disease of the pre-penicillin era, and best known today from HIV-1-infected brains. Microglial rod cells have been implicated in cortical 'synaptic stripping' but their exact role has remained unclear. This is due at least in part to a scarcity of experimental models. Now we have noted these rod microglia after experimental diffuse brain injury in brain regions that have an associated sensory sensitivity. Here, we describe the time course, location, and surrounding architecture associated with rod microglia following experimental diffuse traumatic brain injury (TBI).METHODS:Rats were subjected to a moderate midline fluid percussion injury (mFPI), which resulted in transient suppression of their righting reflex (6 to 10 min). Multiple immunohistochemistry protocols targeting microglia with Iba1 and other known microglia markers were undertaken to identify the morphological activation of microglia. Additionally, labeling with Iba1 and cell markers for neurons and astrocytes identified the architecture that surrounds these rod cells.RESULTS:We identified an abundance of Iba1-positive microglia with rod morphology in the primary sensory barrel fields (S1BF). Although present for at least 4 weeks post mFPI, they developed over the first week, peaking at 7 days post-injury. In the absence of contusion, Iba1-positive microglia appear to elongate with their processes extending from the apical and basal ends. These cells then abut one another and lay adjacent to cytoarchitecture of dendrites and axons, with no alignment with astrocytes and oligodendrocytes. Iba1-positive rod microglial cells differentially express other known markers for reactive microglia including OX-6 and CD68.CONCLUSION:Diffuse traumatic brain injury induces a distinct rod microglia morphology, unique phenotype, and novel association between cells / these observations entice further investigation for impact on neurological outcome.
135

Activation of the kynurenine pathway and increased production of the excitotoxin quinolinic acid following traumatic brain injury in humans

Yan, Edwin B., Frugier, Tony, Lim, Chai K., Heng, Benjamin, Sundaram, Gayathri, Tan, May, Rosenfeld, Jeffrey V., Walker, David W., Guillemin, Gilles J., Morganti-Kossmann, Maria C. January 2015 (has links)
ABSTRACT: During inflammation, the kynurenine pathway (KP) metabolises the essential amino acid tryptophan (TRP) potentially contributing to excitotoxicity via the release of quinolinic acid (QUIN) and 3-hydroxykynurenine (3HK). Despite the importance of excitotoxicity in the development of secondary brain damage, investigations on the KP in TBI are scarce. In this study, we comprehensively characterised changes in KP activation by measuring numerous metabolites in cerebrospinal fluid (CSF) from TBI patients and assessing the expression of key KP enzymes in brain tissue from TBI victims. Acute QUIN levels were further correlated with outcome scores to explore its prognostic value in TBI recovery. METHODS: Twenty-eight patients with severe TBI (GCS ≤ 8, three patients had initial GCS = 9-10, but rapidly deteriorated to ≤8) were recruited. CSF was collected from admission to day 5 post-injury. TRP, kynurenine (KYN), kynurenic acid (KYNA), QUIN, anthranilic acid (AA) and 3-hydroxyanthranilic acid (3HAA) were measured in CSF. The Glasgow Outcome Scale Extended (GOSE) score was assessed at 6 months post-TBI. Post-mortem brains were obtained from the Australian Neurotrauma Tissue and Fluid Bank and used in qPCR for quantitating expression of KP enzymes (indoleamine 2,3-dioxygenase-1 (IDO1), kynurenase (KYNase), kynurenine amino transferase-II (KAT-II), kynurenine 3-monooxygenase (KMO), 3-hydroxyanthranilic acid oxygenase (3HAO) and quinolinic acid phosphoribosyl transferase (QPRTase) and IDO1 immunohistochemistry. RESULTS: In CSF, KYN, KYNA and QUIN were elevated whereas TRP, AA and 3HAA remained unchanged. The ratios of QUIN:KYN, QUIN:KYNA, KYNA:KYN and 3HAA:AA revealed that QUIN levels were significantly higher than KYN and KYNA, supporting increased neurotoxicity. Amplified IDO1 and KYNase mRNA expression was demonstrated on post-mortem brains, and enhanced IDO1 protein coincided with overt tissue damage. QUIN levels in CSF were significantly higher in patients with unfavourable outcome and inversely correlated with GOSE scores. CONCLUSION: TBI induced a striking activation of the KP pathway with sustained increase of QUIN. The exceeding production of QUIN together with increased IDO1 activation and mRNA expression in brain-injured areas suggests that TBI selectively induces a robust stimulation of the neurotoxic branch of the KP pathway. QUIN's detrimental roles are supported by its association to adverse outcome potentially becoming an early prognostic factor post-TBI.
136

Associations between TBI, facial emotion recognition, impulse control and aggression in delinquent and vulnerable young people

Tanskanen, Sanna-Leena January 2015 (has links)
Objectives: There is evidence that childhood traumatic brain injury (TBI) is associated with increased risk of offending and violent crime. This study aimed to explore associations between TBI in a group of delinquent and vulnerable young people (VYP) at risk of offending, and facial emotion recognition (FER) abilities, inhibition control (Stop-IT) and self-reported reactive-proactive aggression (RPQ). Methods: There were two studies. The first study used a cross sectional between group design to compare 45 VYP (with and without TBI) and a control group of 59 students on FER task measuring emotion recognition accuracy of six basic emotions. The second study examined differences between TBI and non-TBI groups in the VYP sample (N=21) on a Stop-IT task, FER accuracy and self-reported reactive-proactive aggression. Results: A history of TBI was reported by 60% of the VYP group (48.9% with loss of consciousness [LoC]), whereas 30% of the control group reported a history of TBI (25.4% with LoC). The VYP group (with and without TBI) demonstrated a similar pattern of reduced overall FER accuracy that was significantly different to the control group. Compared to the control group, The VYP groups (with and without TBI) were less accurate on recognising anger, disgust, sadness and surprise, but not happy and fear. There were no significant differences between the TBI- and non-TBI groups. The second study did not find any significant differences between the TBI and non-TBI groups on overall FER accuracy, Stop-IT performance, and RPQ scores. There were also no significant associations between these measures. Conclusions: Future research requires larger samples that enable investigating the association between different severity of TBI, FER and inhibition control ability. Better and more youth-friendly measures are also needed.
137

Traumatic brain injury with particular reference to diffuse traumatic axonal injury subpopulations

Al-Hasani, Omer Hussain January 2011 (has links)
Traumatic brain injury (TBI) remains an important cause of morbidity and mortality within society. TBI may result in both focal and diffuse brain injury. Diffuse traumatic axonal injury (TAI) is an important pathological substrate of TBI, and can be associated with a range of clinical states, ranging from concussion through to death, the clinical severity being associated with a number of factors related to the injury. A retrospective study was conducted using 406 cases with TBI, from the archive of the Academic Department of Pathology (Neuropathology) University of Edinburgh, during the period from1982 and 2005. This cohort was sequential and provided a unique description of the range of pathologies associated with fatal TBI within the Edinburgh catchment area. All the data was collected on a proforma and analysed to provide a description of the incidence in the injury patterns among the Edinburgh cohort. This cohort was then used to provide cases to try and critically assess the mechanisms of axonal injury in TBI. A study was undertaken to investigate TAI in an experimental model of non-impact head injury in a gyrencephalic mammalian model (piglet model) and in human autopsy materials using immunohistochemical analysis of a range of antibodies, and to define the distribution of axonal injury with flow and neurofilament markers in TAI. A further objective was to examine the expression of β-APP as an indicator of impaired axonal transport, three neurofilament markers targeting NF-160, NF-200, and the phosphorylated form of the neurofilament heavy chain (NFH), in different anatomical regions of piglet and human brains. The double immunofluorescence labelling method was then employed to investigate the hypothesis of co-localisation between β-APP and each one of the previous neurofilament markers. The animal studies showed significant differences in NF-160 between sham and injured 3-5 days old piglet cases (6 hour survival) and between 3-5 days sham and injured, when stained with SMI-34 antibody. In 4 weeks old piglet cases (6 hour survival), immunoreactivity of β-APP was significantly higher in injured than control. No other significant differences for any of the antibodies were noted, based on age, velocity, and survival time. Human results suggested that the brainstem had a higher level of β-APP and NF-160 than the corpus callosum and internal capsule. Co-localisation of β-APP with NFs was not a consistent feature of TAI in piglet and human brains, suggesting that markers of impaired axonal transport and neurofilament accumulation are sensitive to TAI, but may highlight different populations involved in the evolution of TAI.
138

Re-Expression of Thrombospondin-1 in the Thalamocortical Whisker Circuit after Experimental Diffuse Traumatic Brain Injury: Potential Role in Mediating Synaptogenesis?

Ogle, Sarah January 2016 (has links)
Introduction: Annually, an estimated 2.5 million traumatic brain injuries (TBI) occur in the United States, of which, over 50,000 result in deaths. Currently, 5.3 million Americans are living with neurological dysfunction secondary to TBIs leading to a $60 billion dollar cost in medical expenses and productivity losses. To date, there are limited treatments available to cure or ease the morbidity of TBI. Despite preventative efforts, traumatic brain injuries (TBI) occur at a staggering rate and it is estimated that 15-20% of survivors develop persistent post-traumatic neurological impairment. The purposed source of neurological dysfunction is a result of circuit reorganization when the brain rebuilds itself. After diffuse TBI, rodents have been shown to develop a late-onset, gain-of-function sensory sensitivity to whisker stimulation; similar to phonophobia and photophobia experienced by human TBI survivors. This morbidity coincides with evidence of post-TBI circuit reorganization, however the etiology of post-traumatic neurological impairment remains largely unknown. Thrombospondin-1 (TSP-1) and thrombospondin-2 (TSP-2) are heavily expressed during pediatric neuronal synapse development. Expression of TSPs, however declines with age. Mechanistically during development, TSP mediates synaptogenesis via bindingα2δ-1 subunit of the voltage-gated calcium channel receptor (α2δ-1). After neurological insult, re-expression of TSPs has been demonstrated and experimental modulation of the TSP/α2δ-1 interaction has led to changes in morbidity. We therefore hypothesize that experimental diffuse TBI will result in re-expression of TSPs, which will be synchronous with increases in synaptic markers in the thalamocortical whisker circuit. Methods: Adult male Sprague-Dawley rats underwent sham or moderate midline fluid percussion brain injury. At multiple time points over 2-months post-injury, expression of TSPs and synaptic markers were quantified from thalamocortical circuit (ventroposterior medial thalamus (VPM), primary somatosensory barrel fields (S1BF)) biopsies using qPCR and automated capillary westerns, respectively. Results: TSP-1 gene expression and protein levels increase in the VPM during the first week after injury. Gene expression of TSP-1 did not significantly change over time in the S1BF, however, there was a significant increase in protein levels in the first and second weeks after injury. No significant changes were demonstrated in synaptic markers in the VPM over the time course. TSP-1 protein levels demonstrated a similar multimodal response to synaptic markers in the S1BF.Conclusion: Re-expression of TSP-1 and synchronous changes in synaptic marker supports a role for TSP-1 mediated synaptogenesis after experimental diffuse TBI in the S1BF. These data positions us for future investigation of pharmacological inhibition of TSP-mediated synaptogenesis after TBI; which may represent a prophylactic strategy against circuit reorganization and neurological dysfunction after TBI.
139

Diffuse traumatic brain injury induces prolonged immune dysregulation and potentiates hyperalgesia following a peripheral immune challenge

Rowe, R. K., Ellis, G. I., Harrison, J. L., Bachstetter, A. D., Corder, G. F., Van Eldik, L. J., Taylor, B. K., Marti, F., Lifshitz, J. 13 May 2016 (has links)
Background: Nociceptive and neuropathic pain occurs as part of the disease process after traumatic brain injury (TBI) in humans. Central and peripheral inflammation, a major secondary injury process initiated by the traumatic brain injury event, has been implicated in the potentiation of peripheral nociceptive pain. We hypothesized that the inflammatory response to diffuse traumatic brain injury potentiates persistent pain through prolonged immune dysregulation. Results: To test this, adult, male C57BL/6 mice were subjected to midline fluid percussion brain injury or to sham procedure. One cohort of mice was analyzed for inflammation-related cytokine levels in cortical biopsies and serum along an acute time course. In a second cohort, peripheral inflammation was induced seven days after surgery/injury with an intraplantar injection of carrageenan. This was followed by measurement of mechanical hyperalgesia, glial fibrillary acidic protein and Iba1 immunohistochemical analysis of neuroinflammation in the brain, and flow cytometric analysis of T-cell differentiation in mucosal lymph. Traumatic brain injury increased interleukin-6 and chemokine ligand 1 levels in the cortex and serum that peaked within 1-9 h and then resolved. Intraplantar carrageenan produced mechanical hyperalgesia that was potentiated by traumatic brain injury. Further, mucosal T cells from brain-injured mice showed a distinct deficiency in the ability to differentiate into inflammation-suppressing regulatory T cells (Tregs). Conclusions: We conclude that traumatic brain injury increased the inflammatory pain associated with cutaneous inflammation by contributing to systemic immune dysregulation. Regulatory T cells are immune suppressors and failure of T cells to differentiate into regulatory T cells leads to unregulated cytokine production which may contribute to the potentiation of peripheral pain through the excitation of peripheral sensory neurons. In addition, regulatory T cells are identified as a potential target for therapeutic rebalancing of peripheral immune homeostasis to improve functional outcome and decrease the incidence of peripheral inflammatory pain following traumatic brain injury.
140

Inhibition of Calpains by Calpastatin: Implications for Cellular and Functional Damage Following Traumatic Brain Injury

Schoch, Kathleen M. 01 January 2013 (has links)
Traumatic brain injury (TBI) is a devastating health problem based on its high incidence, economic burden, and lack of effective pharmacological treatment. Individuals who suffer an injury often experience lifelong disability. TBI results in abrupt, initial cell damage leading to delayed neuronal death. The calcium-activated proteases, calpains, are known to contribute to this secondary neurodegenerative cascade. Prolonged activation of calpains results in proteolysis of numerous cellular substrates including cytoskeletal components, membrane receptors, and cytosolic proteins, contributing to cell demise despite coincident expression of calpastatin, the specific inhibitor of calpains. A comprehensive analysis using two separate calpastatin transgenic mouse lines was performed to test the hypothesis that calpastatin overexpression will reduce posttraumatic calpain activity affording neuroprotection and behavioral efficacy. Increased calpastatin expression was achieved using transgenic mice that overexpress the human calpastatin (hCAST) construct under control of a neuron-specific calcium-calmodulin dependent kinase II alpha or a ubiquitous prion protein promoter. Both transgenic lines exhibited enhanced calpastatin expression within the brain, extending into peripheral tissues under the prion protein promoter. hCAST overexpression significantly reduced protease activity confirmed by reductions in acute calpain-mediated substrate proteolysis in the cortex and hippocampus following controlled cortical impact brain injury. Aspects of posttraumatic motor and cognitive behavioral deficits were also lessened in hCAST transgenic mice compared to their wildtype littermates. However, volumetric analyses of neocortical contusion revealed no histological neuroprotection at either acute or long-term time points in either transgenic line. Partial hippocampal neuroprotection observed at a moderate injury severity in neuron-specific calpastatin overexpressing transgenic mice was lost after severe TBI. Greater levels of calpastatin under the prion protein promoter line failed to protect against hippocampal cell loss after severe brain injury. This study underscores the effectiveness of calpastatin overexpression in reducing calpain-mediated proteolysis and behavioral impairment after TBI, supporting the therapeutic potential for calpain inhibition. However, the reduction in proteolysis without accompanied neocortical neuroprotection suggests the involvement of other factors that are critical for neuronal survival after contusion brain injury. Augmenting calpastatin levels may be an effective method for calpain inhibition and may have efficacy in reducing behavioral morbidity after TBI and neurodegenerative disorders.

Page generated in 0.0267 seconds