219 resultados para Transplant Candidates
Resumo:
Migraineurs experience significant decline in functioning and productivity, which in turn translates into diminished quality of life and a major economic burden on society at large [1]. Although current research has better elucidated the pathophysiology underlying migraine, the exact etiology remains to be defined. Biochemical factors that could potentially disrupt the vascular endothelial function, leading to cortical spreading depression that can activate and affect the trigeminovascular system, are primary candidates for involvement in migraine pathophysiology [2]. The current mechanisms explaining the pathogenesis behind migraine continue to evolve, but theories of variability in cortical excitability, neuronal dysregulation and neurotransmitter/receptor activation are all important and potentially amenable to nutraceutical manipulation [3]. As our knowledge about migraine pathogenesis expands, our current understanding of the complex relationships between pharmacological doses, cofactor and hormone interactions, and neural and pain pathway activities will also advance, creating new avenues for research and migraine treatment development [3].
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Background Selection of candidates for clinical psychology programmes is arguably the most important decision made in determining the clinical psychology workforce. However, there are few models to inform the development of selection tools to support selection procedures. The study, using a factor analytic structure, has operationalised the model predicting applicants' capabilities. Method Eighty-eight clinical applicants for entry into a postgraduate clinical psychology programme were assessed on a series of tasks measuring eight capabilities: guided reflection, communication skills, ethical decision making, writing, conceptual reasoning, empathy, and awareness of mind and self-observation. Results Factor analysis revealed three capabilities: labelled “awareness” accounting for 35.71% of variance; “reflection” accounting for 20.56%; and “reasoning” accounting for 18.24% of variance. Fourth year grade point average (GPA) did not correlate with performance on any of the selection capabilities other than a weak correlation with performance on the ethics capability. Conclusions Eight selection capabilities are identified for the selection of candidates independent of GPA. While the model is tentative, it is hoped that the findings will stimulate the development and validation of assessment procedures with good predictive validity which will benefit the training of clinical psychologists and, ultimately, effective service delivery.
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Objective: To perform a 1-stage meta-analysis of genome-wide association studies (GWAS) of multiple sclerosis (MS) susceptibility and to explore functional consequences of new susceptibility loci. Methods: We synthesized 7 MS GWAS. Each data set was imputed using HapMap phase II, and a per single nucleotide polymorphism (SNP) meta-analysis was performed across the 7 data sets. We explored RNA expression data using a quantitative trait analysis in peripheral blood mononuclear cells (PBMCs) of 228 subjects with demyelinating disease. Results: We meta-analyzed 2,529,394 unique SNPs in 5,545 cases and 12,153 controls. We identified 3 novel susceptibility alleles: rs170934T at 3p24.1 (odds ratio [OR], 1.17; p ¼ 1.6 � 10�8) near EOMES, rs2150702G in the second intron of MLANA on chromosome 9p24.1 (OR, 1.16; p ¼ 3.3 � 10�8), and rs6718520A in an intergenic region on chromosome 2p21, with THADA as the nearest flanking gene (OR, 1.17; p ¼ 3.4 � 10�8). The 3 new loci do not have a strong cis effect on RNA expression in PBMCs. Ten other susceptibility loci had a suggestive p < 1 � 10�6, some of these loci have evidence of association in other inflammatory diseases (ie, IL12B, TAGAP, PLEK, and ZMIZ1). Interpretation: We have performed a meta-analysis of GWAS in MS that more than doubles the size of previous gene discovery efforts and highlights 3 novel MS susceptibility loci. These and additional loci with suggestive evidence of association are excellent candidates for further investigations to refine and validate their role in the genetic architecture of MS.
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Background Loss of heterozygosity (LOH) is an important marker for one of the 'two-hits' required for tumor suppressor gene inactivation. Traditional methods for mapping LOH regions require the comparison of both tumor and patient-matched normal DNA samples. However, for many archival samples, patient-matched normal DNA is not available leading to the under-utilization of this important resource in LOH studies. Here we describe a new method for LOH analysis that relies on the genome-wide comparison of heterozygosity of single nucleotide polymorphisms (SNPs) between cohorts of cases and un-matched healthy control samples. Regions of LOH are defined by consistent decreases in heterozygosity across a genetic region in the case cohort compared to the control cohort. Methods DNA was collected from 20 Follicular Lymphoma (FL) tumor samples, 20 Diffuse Large B-cell Lymphoma (DLBCL) tumor samples, neoplastic B-cells of 10 B-cell Chronic Lymphocytic Leukemia (B-CLL) patients and Buccal cell samples matched to 4 of these B-CLL patients. The cohort heterozygosity comparison method was developed and validated using LOH derived in a small cohort of B-CLL by traditional comparisons of tumor and normal DNA samples, and compared to the only alternative method for LOH analysis without patient matched controls. LOH candidate regions were then generated for enlarged cohorts of B-CLL, FL and DLBCL samples using our cohort heterozygosity comparison method in order to evaluate potential LOH candidate regions in these non-Hodgkin's lymphoma tumor subtypes. Results Using a small cohort of B-CLL samples with patient-matched normal DNA we have validated the utility of this method and shown that it displays more accuracy and sensitivity in detecting LOH candidate regions compared to the only alternative method, the Hidden Markov Model (HMM) method. Subsequently, using B-CLL, FL and DLBCL tumor samples we have utilised cohort heterozygosity comparisons to localise LOH candidate regions in these subtypes of non-Hodgkin's lymphoma. Detected LOH regions included both previously described regions of LOH as well as novel genomic candidate regions. Conclusions We have proven the efficacy of the use of cohort heterozygosity comparisons for genome-wide mapping of LOH and shown it to be in many ways superior to the HMM method. Additionally, the use of this method to analyse SNP microarray data from 3 common forms of non-Hodgkin's lymphoma yielded interesting tumor suppressor gene candidates, including the ETV3 gene that was highlighted in both B-CLL and FL.
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Background Glutamate is the principal excitatory neurotransmitter in the central nervous system which acts by the activation of either ionotropic (AMPA, NMDA and kainate receptors) or G-protein coupled metabotropic receptors. Glutamate is widely accepted to play a major role in the path physiology of migraine as implicated by data from animal and human studies. Genes involved in synthesis, metabolism and regulation of both glutamate and its receptors could be, therefore, considered as potential candidates for causing/predisposing to migraine when mutated. Methods The association of polymorphic variants of GRIA1-GRIA4 genes which encode for the four subunits (GluR1-GluR4) of the alpha-amino-3- hydroxy-5-methyl-4-isoxazole-propionic acid (AMPA) receptor for glutamate was tested in migraineurs with and without aura (MA and MO) and healthy controls. Results Two variants in the regulative regions of GRIA1 (rs2195450) and GRIA3 (rs3761555) genes resulted strongly associated with MA (P = 0.00002 and P = 0.0001, respectively), but not associated with MO, suggesting their role in cortical spreading depression. Whereas the rs548294 variant in GRIA1 gene showed association primarily with MO phenotype, supporting the hypothesis that MA and MO phenotypes could be genetically related. These variants modify binding sites for transcription factors altering the expression of GRIA1 and GRIA3 genes in different conditions. Conclusions This study represents the first genetic evidence of a link between glutamate receptors and migraine.
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Postgraduate candidates in the creative arts encounter unique challenges when writing an exegesis (the written document that accompanies creative work as a thesis). As a practitioner-researcher, they must adopt a dual perspective–looking out towards an established field of research, exemplars and theories, as well as inwards towards their experiential creative processes and practice. This dual orientation provides clear benefits, for it enables them to situate the research within its field and make objective claims for the research methodologies and outcomes while maintaining an intimate, voiced relationship with the practice. However, a dual orientation introduces considerable complexities in the writing. It requires a reconciliation of multi-perspectival subject positions: the disinterested academic posture of the observer/ethnographer/analyst/theorist at times; and the invested, subjective stance the practitioner/producer at others. It requires the author to negotiate a range of writing styles and speech genres–from the formal, polemical style of the theorist to the personal, questioning and emotive voice of reflexivity. Moreover, these multi-variant orientations, subject positions, styles and voices must be integrated into a unified and coherent text. In this chapter I offer a conceptual framework and strategies for approaching this relatively new genre of thesis. I begin by summarizing the characteristics of what has begun to emerge as the predominant model of exegesis (the dual-oriented ‘Connective’ exegesis). Framing it against theoretical and philosophical understandings of polyvocality and matrixicality, I go on to point to recent textual models that provide precedents for connecting differently oriented perspectives, subjectivities and voices. I then turn to emergent archives of practice-led research to explain how the challenge of writing a ‘Connective’ exegesis has so far been resolved by higher degree research (HDR) candidates. Exemplars illustrate a range of strategies they have used to compose a multi-perspectival text, reconcile the divergent subject positions of the practitioner researcher, and harmonize the speech genres of a ployvocal text.
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The cancer stem cell hypothesis states that tumours arise from cells with the ability to self-renew and differentiate into multiple cell types, and that these cells persist in tumors as a distinct population that can cause disease relapse and hence metastasis. The crux of this hypothesis is that these cells are the only cells capable of, by themselves, giving rise to new tumours. What proportion of a tumour consists of these stem cells, where are they localised, how are they regulated, and how can we identify them? The stromal cells embedded within the extracellular matrix (ECM) not only provide a scaffold but also produce ECM constituents for use by stem cells. Heparan sulfate proteoglycans (HSPGs) are ubiquitous to this cell niche and interact with a large number of ligands including growth factors, their receptors, and ECM structural components. It is still unclear whether ECM degradation and subsequent metastasis is a result of proteases produced by the tumour cells themselves or by cells within the stromal compartment. The identification of the cellular origin of cancer stem cells along with microenvironmental changes involved in the initiation, progression and the malignant conversion of all cancers is critical to the development of targeted therapeutics. As ubiquitous members of the ECM microenvironment and hence the cancer cell niche, HSPGs are candidates for a central role in these processes.
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This article covers lymphoproliferative disorders in patients with primary or acquired immunodeficiencies. Primary immunodeficiences include Ataxia Telangiectasia and X-linked disorders such as Wiskott-Aldrich syndrome. Acquired immunodeficiencies predominantly occur in the setting of infection with the Human Immunodeficiency Virus or arise following immunosuppressive therapy administered after organ transplantation. The rising incidence of HIV throughout the world and the dramatic increase in transplant surgery since the 1990's suggest that these lymphomas will remain an important health problem. Evidence for lymphoma developing as a result of treatment with methotrexate or Tumour Necrosis Factor Antagonists for autoimmune entities will also be reviewed. The lymphoproliferations that occur with immunodeficiency are extremely heterogenous. In part this reflects the diversity of the causal immune defect. The most striking clinical characteristic is the high frequency of extranodal disease. Frequently, these lymphomas are driven by viruses such as Epstein-Barr virus (EBV), although the lack of EBV in a proportion indicates that alternate pathways must also be involved in the pathogenesis. Lastly, discussion will centre on mechanisms utilized by lymphomas in the immunodeficient as these may have applications to lymphomas in the "immunocompetent", by serving as a paradigm for the altered immunoregulatory environment present in many lymphoma sub-types.
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Multiple sclerosis (MS) is a serious neurological disorder affecting young Caucasian individuals, usually with an age of onset at 18 to 40 years old. Females account for approximately 60x of MS cases and the manifestation and course of the disease is highly variable from patient to patient. The disorder is characterised by the development of plaques within the central nervous system (CNS). Many gene expression studies have been undertaken to look at the specific patterns of gene transcript levels in MS. Human tissues and experimental mice were used in these gene-profiling studies and a very valuable and interesting set of data has resulted from these various expression studies. In general, genes showing variable expression include mainly immunological and inflammatory genes, stress and antioxidant genes, as well as metabolic and central nervous system markers. Of particular interest are a number of genes localised to susceptible loci previously shown to be in linkage with MS. However due to the clinical complexity of the disease, the heterogeneity of the tissues used in expression studies, as well as the variable DNA chips/membranes used for the gene profiling, it is difficult to interpret the available information. Although this information is essential for the understanding of the pathogenesis of MS, it is difficult to decipher and define the gene pathways involved in the disorder. Experiments in gene expression profiling in MS have been numerous and lists of candidates are now available for analysis. Researchers have investigated gene expression in peripheral mononuclear white blood cells (PBMCs), in MS animal models Experimental Allergic Encephalomyelitis (EAE) and post mortem MS brain tissues. This review will focus on the results of these studies.
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OBJECTIVE: To investigate the role of the dopamine receptor genes, DRD1, DRD3, and DRD5 in the pathogenesis of migraine. BACKGROUND: Migraine is a chronic debilitating disorder affecting approximately 12% of the white population. The disease shows strong familial aggregation and presumably has a genetic basis, but at present, the type and number of genes involved is unclear. The study of candidate genes can prove useful in the identification of genes involved in complex diseases such as migraine, especially if the contribution of the gene to phenotypic expression is minor. Genes coding for proteins involved in dopamine metabolism have been implicated in a number of neurologic conditions and may play a contributory role in migraine. Hence, genes that code for enzymes and receptors modulating dopaminergic activity are good candidates for investigation of the molecular genetic basis of migraine. METHODS: We tested 275 migraineurs and 275 age- and sex-matched individuals free of migraine. Genotypic results were determined by restriction endonuclease digestion of polymerase chain reaction products to detect DRD1 and DRD3 alleles and by Genescan analysis after polymerase chain reaction using fluorescently labelled oligonucleotide primers for the DRD5 marker. RESULTS: Results of chi-square statistical analyses indicated that the allele distribution for migraine cases compared to controls was not significantly different for any of the three tested gene markers (chi2 = 0.1, P =.74 for DRD1; chi2 = 1.8, P =.18 for DRD3; and chi2 = 20.3, P =.08 for DRD5). CONCLUSIONS: These findings offer no evidence for allelic association between the tested dopamine receptor gene polymorphisms and the more prevalent forms of migraine and, therefore, do not support a role for these genes in the pathogenesis of the disorder.
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Nitric oxide synthase and renal kallikrein are both involved in blood pressure regulation. Genes for these enzymes may, therefore, be considered candidates for hypertension pathogenesis. 2. In the present study, genotypes for nitric oxide synthase and renal kallikrein microsatellite markers were determined in a cross-sectional association analysis of hypertensive patients and normotensive control subjects. 3. Results from this study did not indicate an association of either of the candidate gene polymorphisms with essential hypertension. Hence, findings for this study do not support a role for these genes in human hypertension.
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Right heart dysfunction is one of the most serious complications following implantation of a left ventricular assist device (LVAD), often leading to the requirement for short or long term right ventricular support (RVAD). The inflow cannulation site induces major haemodynamic changes and so there is a need to optimize the site used depending on the patient's condition. Therefore, this study evaluated and compared the haemodynamic influence of right atrial (RAC) and right ventricular (RVC) inflow cannulation sites. An in-vitro, variable heart failure, mock circulation loop was used to compare RAC and RVC in mild and severe biventricular heart failure (BHF) conditions. In the severe BHF condition, higher ventricular ejection fraction (RAC: 13.6%, RVC: 32.7%) and thus improved heart chamber and RVAD washout was observed with RVC, which suggested this strategy might be preferable for long term support (ie. bridge to transplant or destination therapy) to reduce the risk of thrombus formation. In the mild BHF condition, higher pulmonary valve flow (RAC: 3.33 L/min, RVC: 1.97 L/min) and lower right ventricular stroke work (RAC: 0.10 W, RVC: 0.13 W) and volumes were recorded with RAC. These results indicate an improved potential for myocardial recovery, thus RAC should be chosen in this condition. This in-vitro study suggests that RVAD inflow cannulation site should be chosen on a patient-specific basis with a view to the support strategy to promote myocardial recovery or reduce the risk of long-term complications.
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The synthesis of organic semiconducting materials based on silver and copper-TCNQ (TCNQ = 7,7,8,8-tetracyanoquinodimethane) and their fluorinated analogues has received a significant amount of attention due to their potential use in organic electronic applications. However, there is a scarcity in the identification of different applications for which these interesting materials may be suitable candidates. In this work, we address this by investigating the catalytic properties of such materials for the electron transfer reaction between ferricyanide and thiosulphate ions in aqueous solution, which to date has been almost solely limited to metallic nanomaterials. Significantly it was found that all the materials investigated, namely CuTCNQ, AgTCNQ, CuTCNQF4 and AgTCNQF4, were catalytically active and, interestingly, the fluorinated analogues were superior. AgTCNQF4 demonstrated the highest activity and was tested for its stability and re-usability for up to 50 cycles without degradation in performance. The catalytic reaction was monitored via UV-vis spectroscopy and open circuit potential versus time measurements, as well as an investigation of the transport properties of the films via electrochemical impedance spectroscopy. It is suggested that morphology and bulk conductivity are not the limiting factors, but rather the balance between the accumulated surface charge from electron injection via thiosulphate ions on the catalyst surface and transfer to the ferricyanide ions which controls the reaction rate. The facile fabrication of re-usable surface confined organic materials that are catalytically active may have important uses for many more electron transfer reactions.
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Upgrading old buildings with the evolution of building requirements, this project investigates new approaches that can be applied to strengthen our own heritage buildings using historical and comparative analysis of heritage building restorations locally and abroad. Within the newly developing field of Heritage Engineering, it evaluates the innovative Concrete Overlay technique adapted to building restoration of the Brisbane City Hall. This study aims to extend the application of Concrete Overlay techniques and determine its compatibility specifically to heritage buildings. Concrete overlay involves drilling new reinforcement and placing concrete on top of the existing structure. It is akin to a bone transplant or bone grafting in the case of a human being and has been used by engineers to strengthen newer bridges.
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The development of hydrogels tailored for cartilage tissue engineering has been a research and clinical goal for over a decade. Directing cells towards a chondrogenic phenotype and promoting new matrix formation are significant challenges that must be overcome for the successful application of hydrogels in cartilage tissue therapies. Gelatin-methacrylamide (Gel-MA) hydrogels have shown promise for the repair of some tissues, but they have not been extensively investigated for cartilage tissue engineering. We encapsulated human chondrocytes in gel-MA based hydrogels, and show that with the incorporation of small quantities of photo-crosslinkable hyaluronic acid methacrylate (HA-MA), and to a lesser extent chondroitin sulfate methacrylate (CS-MA), chondrogenesis and mechanical properties can be enhanced. The addition of HA-MA to Gel-MA constructs resulted in more rounded cell morphologies, enhanced chondrogenesis as assessed by gene expression and immunofluorescence, and increased quantity and distribution of the newly synthesised ECM throughout the construct. Consequently, while the compressive moduli of control Gel-MA constructs increased by 26 kPa after 8 weeks culture, constructs with HA-MA and CS-MA increased by 96 kPa. The enhanced chondrogenic differentiation, distribution of ECM, and improved mechanical properties make these materials potential candidates for cartilage tissue engineering applications.