1,064 research outputs found

    Growth cone behavior and production of traction force.

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    Tension and compression in the cytoskeleton of PC 12 neurites.

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    Is it possible to separate the graft-versus-leukemia (GVL) effect against B cell acute lymphoblastic leukemia from graft-versus-host disease (GVHD) after hematopoietic cell transplant?

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    Hematopoietic cell transplant is a curative therapy for many pediatric patients with high risk acute lymphoblastic leukemia. Its therapeutic mechanism is primarily based on the generation of an alloreactive graft-versus-leukemia effect that can eliminate residual leukemia cells thus preventing relapse. However its efficacy is diminished by the concurrent emergence of harmful graft-versus-host disease disease which affects healthly tissue leading to significant morbidity and mortality. The purpose of this review is to describe the interventions that have been trialed in order to augment the beneficial graft-versus leukemia effect post-hematopoietic cell transplant while limiting the harmful consequences of graft-versus-host disease. This includes many emerging and promising strategies such a

    Highly conserved molecular pathways, including Wnt signaling, promote functional recovery from spinal cord injury in lampreys

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    © The Author(s), 2018. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Scientific Reports 8 (2018): 742, doi:10.1038/s41598-017-18757-1.In mammals, spinal cord injury (SCI) leads to dramatic losses in neurons and synaptic connections, and consequently function. Unlike mammals, lampreys are vertebrates that undergo spontaneous regeneration and achieve functional recovery after SCI. Therefore our goal was to determine the complete transcriptional responses that occur after SCI in lampreys and to identify deeply conserved pathways that promote regeneration. We performed RNA-Seq on lamprey spinal cord and brain throughout the course of functional recovery. We describe complex transcriptional responses in the injured spinal cord, and somewhat surprisingly, also in the brain. Transcriptional responses to SCI in lampreys included transcription factor networks that promote peripheral nerve regeneration in mammals such as Atf3 and Jun. Furthermore, a number of highly conserved axon guidance, extracellular matrix, and proliferation genes were also differentially expressed after SCI in lampreys. Strikingly, ~3% of differentially expressed transcripts belonged to the Wnt pathways. These included members of the Wnt and Frizzled gene families, and genes involved in downstream signaling. Pharmacological inhibition of Wnt signaling inhibited functional recovery, confirming a critical role for this pathway. These data indicate that molecular signals present in mammals are also involved in regeneration in lampreys, supporting translational relevance of the model.We gratefully acknowledge support from the National Institutes of Health (R03NS078519 to OB; R01GM104123 to JJS; R01NS078165 to JRM), The Feinstein Institute for Medical Research and The Marine Biological Laboratory, including the Charles Evans Foundation Research Award, the Albert and Ellen Grass Foundation Faculty Research Award, and The Eugene and Millicent Bell Fellowship Fund in Tissue Engineering

    Challenges and support needs of parents and children when a parent is at end of life: A systematic review

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    Background: Preparing children for the death of a parent is challenging. Parents are often uncertain if and how to communicate and support their children. Many parents feel it is protecting their children by not telling them about the prognosis. Children less prepared for parental death from a terminal illness are more susceptive to later adversities. To facilitate coping and moderate for such adversities, there is a need to gain insight and understand the experience and challenges confronted by families. Aim: This review synthesised evidence on the experiences of parents and children when a parent is at end of life to discern their challenges, support needs and factors that facilitated good practice. Design: Mixed-methods systematic review. Data sources: Four electronic databases (CINAHL, PubMed, PsycINFO and Ovid MEDLINE) using MeSH terms and word searches in October 2018. Studies were not limited by year of publication, language or country. Grey literature searches were also completed on Google Scholar and OpenGrey. Results: In all, 7829 records were identified; 27 qualitative and 0 quantitative studies met the inclusion criteria. Eight descriptive themes were identified, further categorised into two broad themes: (1) barriers and facilitators in sharing the news that a parent is dying and (2) strategies to manage the changing situation. Conclusion: Lack of understanding in relation to the parent’s prognosis, denial and feeling ill-equipped were suggested as barriers for parents to share the news with their children. Engagement with social networks, including extended family relatives and peers, and maintaining routines such as attending school were suggested supportive by parents and children. Findings are limited primarily to White, middle-class two-parent families. A number of areas for future research are identified.</p

    Apraxia and motor dysfunction in corticobasal syndrome

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    Background: Corticobasal syndrome (CBS) is characterized by multifaceted motor system dysfunction and cognitive disturbance; distinctive clinical features include limb apraxia and visuospatial dysfunction. Transcranial magnetic stimulation (TMS) has been used to study motor system dysfunction in CBS, but the relationship of TMS parameters to clinical features has not been studied. The present study explored several hypotheses; firstly, that limb apraxia may be partly due to visuospatial impairment in CBS. Secondly, that motor system dysfunction can be demonstrated in CBS, using threshold-tracking TMS, and is linked to limb apraxia. Finally, that atrophy of the primary motor cortex, studied using voxel-based morphometry analysis (VBM), is associated with motor system dysfunction and limb apraxia in CBS.   Methods: Imitation of meaningful and meaningless hand gestures was graded to assess limb apraxia, while cognitive performance was assessed using the Addenbrooke's Cognitive Examination - Revised (ACE-R), with particular emphasis placed on the visuospatial subtask. Patients underwent TMS, to assess cortical function, and VBM.   Results: In total, 17 patients with CBS (7 male, 10 female; mean age 64.4+/2 6.6 years) were studied and compared to 17 matched control subjects. Of the CBS patients, 23.5% had a relatively inexcitable motor cortex, with evidence of cortical dysfunction in the remaining 76.5% patients. Reduced resting motor threshold, and visuospatial performance, correlated with limb apraxia. Patients with a resting motor threshold <50% performed significantly worse on the visuospatial sub-task of the ACE-R than other CBS patients. Cortical function correlated with atrophy of the primary and pre-motor cortices, and the thalamus, while apraxia correlated with atrophy of the pre-motor and parietal cortices.   Conclusions: Cortical dysfunction appears to underlie the core clinical features of CBS, and is associated with atrophy of the primary motor and pre-motor cortices, as well as the thalamus, while apraxia correlates with pre-motor and parietal atrophy

    Evolutionary autonomous agents and the nature of apraxia

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    BACKGROUND: Evolutionary autonomous agents are robots or robot simulations whose controller is a dynamical neural network and whose evolution occurs autonomously under the guidance of a fitness function without the detailed or explicit direction of an external programmer. They are embodied agents with a simple neural network controller and as such they provide the optimal forum by which sensorimotor interactions in a specified environment can be studied without the computational assumptions inherent in standard neuroscience. METHODS: Evolutionary autonomous agents were evolved that were able to perform identical movements under two different contexts, one which represented an automatic movement and one which had a symbolic context. In an attempt to model the automatic-voluntary dissociation frequently seen in ideomotor apraxia, lesions were introduced into the neural network controllers resulting in a behavioral dissociation with loss of the ability to perform the movement which had a symbolic context and preservation of the simpler, automatic movement. RESULTS: Analysis of the changes in the hierarchical organization of the networks in the apractic EAAs demonstrated consistent changes in the network dynamics across all agents with loss of longer duration time scales in the network dynamics. CONCLUSION: The concepts of determinate motor programs and perceptual representations that are implicit in the present day understanding of ideomotor apraxia are assumptions inherent in the computational understanding of brain function. The strength of the present study using EAAs to model one aspect of ideomotor apraxia is the absence of these assumptions and a grounding of all sensorimotor interactions in an embodied, autonomous agent. The consistency of the hierarchical changes in the network dynamics across all apractic agents demonstrates that this technique is tenable and will be a valuable adjunct to a computational formalism in the understanding of the physical basis of neurological disorders
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