301 research outputs found

    Minor and Unsystematic Cortical Topographic Changes of Attention Correlates between Modalities

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    In this study we analyzed the topography of induced cortical oscillations in 20 healthy individuals performing simple attention tasks. We were interested in qualitatively replicating our recent findings on the localization of attention-induced beta bands during a visual task [1], and verifying whether significant topographic changes would follow the change of attention to the auditory modality. We computed corrected latency averaging of each induced frequency bands, and modeled their generators by current density reconstruction with Lp-norm minimization. We quantified topographic similarity between conditions by an analysis of correlations, whereas the inter-modality significant differences in attention correlates were illustrated in each individual case. We replicated the qualitative result of highly idiosyncratic topography of attention-related activity to individuals, manifested both in the beta bands, and previously studied slow potential distributions [2]. Visual inspection of both scalp potentials and distribution of cortical currents showed minor changes in attention-related bands with respect to modality, as compared to the theta and delta bands, known to be major contributors to the sensory-related potentials. Quantitative results agreed with visual inspection, supporting to the conclusion that attention-related activity does not change much between modalities, and whatever individual changes do occur, they are not systematic in cortical localization across subjects. We discuss our results, combined with results from other studies that present individual data, with respect to the function of cortical association areas

    Mild Joint Symptoms Are Associated with Lower Risk of Falls than Asymptomatic Individuals with Radiological Evidence of Osteoarthritis

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    Osteoarthritis (OA) exacerbates skeletal muscle functioning, leading to postural instability and increased falls risk. However, the link between impaired physical function, OA and falls have not been elucidated. We investigated the role of impaired physical function as a potential mediator in the association between OA and falls. This study included 389 participants [229 fallers (≥2 falls or one injurious fall in the past 12 months), 160 non-fallers (no history of falls)], age (≥65 years) from a randomized controlled trial, the Malaysian Falls Assessment and Intervention Trial (MyFAIT). Physical function was assessed using Timed Up and Go (TUG) and Functional Reach (FR) tests. Knee and hip OA were diagnosed using three methods: Clinical, Radiological and Self-report. OA symptom severity was assessed using the Western Ontario and McMaster Universities Arthritis Index (WOMAC). The total WOMAC score was categorized to asymptomatic, mild, moderate and severe symptoms. Individuals with radiological OA and ‘mild’ overall symptoms on the WOMAC score had reduced risk of falls compared to asymptomatic OA [OR: 0.402(0.172–0.940), p = 0.042]. Individuals with clinical OA and ‘severe’ overall symptoms had increased risk of falls compared to those with ‘mild’ OA [OR: 4.487(1.883–10.693), p = 0.005]. In individuals with radiological OA, mild symptoms appear protective of falls while those with clinical OA and severe symptoms have increased falls risk compared to those with mild symptoms. Both relationships between OA and falls were not mediated by physical limitations. Larger prospective studies are needed for further evaluation

    Clinical effects of Garcinia kola in knee osteoarthritis

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    <p>Abstract</p> <p>Objectives</p> <p>Over the past years, there has been a growing number of knee osteoarthritis (KOA) patients who are not willing to comply with long-term non-steroidal anti-inflammatory drugs (NSAID) treatment and wish to use herbal anti- rheumatic medicine. This study assessed the clinical effects of <it>Garcinia kola </it>(GK) in KOA patients.</p> <p>Patients and methods</p> <p>Prospective randomized, placebo controlled, double blind, clinical trial approved by the institutional medical ethics review board and written informed consent obtained from each patient. All KOA patients presenting at the Obafemi Awolowo University Teaching Hospital complex were recruited into the study. The patients were grouped into four (A = Placebo, B = Naproxen, C = <it>Garcinia kola</it>, D = Celebrex). The drugs and placebo were given twice a day per oral route. Each dose consisted of 200 mg of <it>G. kola</it>, Naproxen (500 mg), Celebrex (200 mg) and Ascorbic acid (100 mg). The primary outcome measure over six weeks study period was the change in mean WOMAC pain visual analogue scales (VAS). Secondary outcome measures included the mean change in joint stiffness and physical function (mobility/walking).</p> <p>Results</p> <p>143 patients were recruited, 84 (58.7%, males – 24, females – 60) satisfied the selection criteria and completed the study. The effect of knee osteoarthritis bilateralism among the subjects was not significant on their outcome (p > 0.05). The change in the mean WOMAC pain VAS after six weeks of <it>G. kola </it>was significantly reduced compared to the placebo (p < 0.001). Multiple comparisons of the mean VAS pain change of <it>G. kola </it>group was not lowered significantly against the naproxen and celebrex groups (p > 0.05). The onset of <it>G. kola </it>symptomatic pain relief was faster than the placebo (p < 0.001). However, it was slower than the active comparators (p > 0.05). The duration of therapeutic effect of <it>Garcinia kola </it>was longer than the placebo (p > 0.001). <it>G. kola </it>period of effect was less than naproxen and celebrex (p < 0.001). <it>G. kola </it>subjects had improved mean change mobility/walking after six weeks better than the control group(p < 0.001). The mean change in mobility of the <it>G. kola </it>group when compared to the active comparators was not significantly better (p < 0.05). The mean change of knee joint stiffness (p < 0.001) and the change of mean WOMAC score (p < 0.001) were improved on <it>Garcinia kola </it>as compared to the placebo. The mid term outcome of eleven <it>Garcinia kola </it>subjects after cessation of use had a mean pain relief period of 17.27 +/- 5.15 days (range: 9–26 days). There was no significant cardiovascular, renal or drug induced adverse reaction to <it>Garcinia kola</it>.</p> <p>Conclusion</p> <p><it>Garcinia kola </it>appeared to have clinically significant analgesic/anti-inflammatory effects in knee osteoarthritis patients. <it>Garcinia kola </it>is a potential osteoarthritis disease activity modifier with good mid term outcome. Further studies are required for standardization of dosages and to determine long-term effects.</p

    HTLV-1 Tax Mediated Downregulation of miRNAs Associated with Chromatin Remodeling Factors in T Cells with Stably Integrated Viral Promoter

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    RNA interference (RNAi) is a natural cellular mechanism to silence gene expression and is predominantly mediated by microRNAs (miRNAs) that target messenger RNA. Viruses can manipulate the cellular processes necessary for their replication by targeting the host RNAi machinery. This study explores the effect of human T-cell leukemia virus type 1 (HTLV-1) transactivating protein Tax on the RNAi pathway in the context of a chromosomally integrated viral long terminal repeat (LTR) using a CD4+ T-cell line, Jurkat. Transcription factor profiling of the HTLV-1 LTR stably integrated T-cell clone transfected with Tax demonstrates increased activation of substrates and factors associated with chromatin remodeling complexes. Using a miRNA microarray and bioinformatics experimental approach, Tax was also shown to downregulate the expression of miRNAs associated with the translational regulation of factors required for chromatin remodeling. These observations were validated with selected miRNAs and an HTLV-1 infected T cells line, MT-2. miR-149 and miR-873 were found to be capable of directly targeting p300 and p/CAF, chromatin remodeling factors known to play critical role in HTLV-1 pathogenesis. Overall, these results are first in line establishing HTLV-1/Tax-miRNA-chromatin concept and open new avenues toward understanding retroviral latency and/or replication in a given cell type

    Cerebellar Asymmetry and Cortical Connectivity in Monozygotic Twins with Discordant Handedness

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    Handedness differentiates patterns of neural asymmetry and interhemispheric connectivity in cortical systems that underpin manual and language functions. Contemporary models of cerebellar function incorporate complex motor behaviour and higher-order cognition, expanding upon earlier, traditional associations between the cerebellum and motor control. Structural MRI defined cerebellar volume asymmetries and correlations with corpus callosum (CC) size were compared in 19 pairs of adult female monozygotic twins strongly discordant for handedness (MZHd). Volume and asymmetry of cerebellar lobules were obtained using automated parcellation.CC area and regional widths were obtained from midsagittal planimetric measurements. Within the cerebellum and CC, neurofunctional distinctions were drawn between motor and higher-order cognitive systems. Relationships amongst regional cerebellar asymmetry and cortical connectivity (as indicated by CC widths) were investigated. Interactions between hemisphere and handedness in the anterior cerebellum were due to a larger right-greater-than-left hemispheric asymmetry in right-handed (RH) compared to left-handed (LH) twins. In LH twins only, anterior cerebellar lobule volumes (IV, V) for motor control were associated with CC size, particularly in callosal regions associated with motor cortex connectivity. Superior posterior cerebellar lobule volumes (VI, Crus I, Crus II, VIIb) showed no correlation with CC size in either handedness group. These novel results reflected distinct patterns of cerebellar-cortical relationships delineated by specific CC regions and an anterior-posterior cerebellar topographical mapping. Hence, anterior cerebellar asymmetry may contribute to the greater degree of bilateral cortical organisation of frontal motor function in LH individuals

    Rescue of Photoreceptor Degeneration by Curcumin in Transgenic Rats with P23H Rhodopsin Mutation

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    The P23H mutation in the rhodopsin gene causes rhodopsin misfolding, altered trafficking and formation of insoluble aggregates leading to photoreceptor degeneration and autosomal dominant retinitis pigmentosa (RP). There are no effective therapies to treat this condition. Compounds that enhance dissociation of protein aggregates may be of value in developing new treatments for such diseases. Anti-protein aggregating activity of curcumin has been reported earlier. In this study we present that treatment of COS-7 cells expressing mutant rhodopsin with curcumin results in dissociation of mutant protein aggregates and decreases endoplasmic reticulum stress. Furthermore we demonstrate that administration of curcumin to P23H-rhodopsin transgenic rats improves retinal morphology, physiology, gene expression and localization of rhodopsin. Our findings indicate that supplementation of curcumin improves retinal structure and function in P23H-rhodopsin transgenic rats. This data also suggest that curcumin may serve as a potential therapeutic agent in treating RP due to the P23H rhodopsin mutation and perhaps other degenerative diseases caused by protein trafficking defects

    Effect of Audiovisual Training on Monaural Spatial Hearing in Horizontal Plane

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    The article aims to test the hypothesis that audiovisual integration can improve spatial hearing in monaural conditions when interaural difference cues are not available. We trained one group of subjects with an audiovisual task, where a flash was presented in parallel with the sound and another group in an auditory task, where only sound from different spatial locations was presented. To check whether the observed audiovisual effect was similar to feedback, the third group was trained using the visual feedback paradigm. Training sessions were administered once per day, for 5 days. The performance level in each group was compared for auditory only stimulation on the first and the last day of practice. Improvement after audiovisual training was several times higher than after auditory practice. The group trained with visual feedback demonstrated a different effect of training with the improvement smaller than the group with audiovisual training. We conclude that cross-modal facilitation is highly important to improve spatial hearing in monaural conditions and may be applied to the rehabilitation of patients with unilateral deafness and after unilateral cochlear implantation

    Increased peri-ductal collagen micro-organization may contribute to raised mammographic density

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    BACKGROUND: High mammographic density is a therapeutically modifiable risk factor for breast cancer. Although mammographic density is correlated with the relative abundance of collagen-rich fibroglandular tissue, the causative mechanisms, associated structural remodelling and mechanical consequences remain poorly defined. In this study we have developed a new collaborative bedside-to-bench workflow to determine the relationship between mammographic density, collagen abundance and alignment, tissue stiffness and the expression of extracellular matrix organising proteins. METHODS: Mammographic density was assessed in 22 post-menopausal women (aged 54–66 y). A radiologist and a pathologist identified and excised regions of elevated non-cancerous X-ray density prior to laboratory characterization. Collagen abundance was determined by both Masson’s trichrome and Picrosirius red staining (which enhances collagen birefringence when viewed under polarised light). The structural specificity of these collagen visualisation methods was determined by comparing the relative birefringence and ultrastructure (visualised by atomic force microscopy) of unaligned collagen I fibrils in reconstituted gels with the highly aligned collagen fibrils in rat tail tendon. Localised collagen fibril organisation and stiffness was also evaluated in tissue sections by atomic force microscopy/spectroscopy and the abundance of key extracellular proteins was assessed using mass spectrometry. RESULTS: Mammographic density was positively correlated with the abundance of aligned periductal fibrils rather than with the abundance of amorphous collagen. Compared with matched tissue resected from the breasts of low mammographic density patients, the highly birefringent tissue in mammographically dense breasts was both significantly stiffer and characterised by large (>80 μm long) fibrillar collagen bundles. Subsequent proteomic analyses not only confirmed the absence of collagen fibrosis in high mammographic density tissue, but additionally identified the up-regulation of periostin and collagen XVI (regulators of collagen fibril structure and architecture) as potential mediators of localised mechanical stiffness. CONCLUSIONS: These preliminary data suggest that remodelling, and hence stiffening, of the existing stromal collagen microarchitecture promotes high mammographic density within the breast. In turn, this aberrant mechanical environment may trigger neoplasia-associated mechanotransduction pathways within the epithelial cell population. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s13058-015-0664-2) contains supplementary material, which is available to authorized users

    Blast resilience of composite sandwich panels with hybrid glass-fibre and carbon-fibre skins

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    The development of composite materials through hybridisation is receiving a lot of interest; due to the multiple benefits, this may bring to many industries. These benefits include decreased brittle behaviour, which is an inherent weakness for composite materials, and the enhancement of mechanical properties due to the hybrid effect, such as tensile and flexural strength. The effect of implementing hybrid composites as skins on composite sandwich panels is not well understood under high strain rate loading, including blast loading. This paper investigates the blast resilience of two types of hybrid composite sandwich panel against a full-scale explosive charge. Two hybrid composite sandwich panels were mounted at a 15 m stand-off distance from a 100 kg nitromethane charge. The samples were designed to reveal whether the fabric layup order of the skins influences blast response. Deflection of the sandwich panels was recorded using high-speed 3D digital image correlation (DIC) during the blast. It was concluded that the combination of glass-fibre reinforced polymer (GFRP) and carbon-fibre reinforced polymer (CFRP) layers in hybrid laminate skins of sandwich panels decreases the normalised deflection compared to both GFRP and CFRP panels by up to 41 and 23%, respectively. The position of the glass-fibre and carbon-fibre layers does not appear to affect the sandwich panel deflection and strain. A finite element model has successfully been developed to predict the elastic response of a hybrid panel under air blast loading. The difference between the maximum central displacement of the experimental data and numerical simulation was ca. 5% for the hybrid panel evaluated
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