157 research outputs found

    An MCMC study of general squark flavour mixing in the MSSM

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    We present an extensive study of non-minimally flavour violating (NMFV) terms in the Lagrangian of the Minimal Supersymmetric Standard Model (MSSM). We impose a variety of theoretical and experimental constraints and perform a detailed scan of the parameter space by means of a Markov Chain Monte-Carlo (MCMC) setup. This represents the first study of several non-zero flavour-violating elements within the MSSM. We present the results of the MCMC scan with a special focus on the flavour-violating parameters. Based on these results, we define benchmark scenarios for future studies of NMFV effects at the LHC.Comment: 8 pages, 3 figures. To appear in the proceedings of the European Physical Society Conference on High Energy Physics 2015 (EPS-HEP 2015), Vienna, Austria, 22nd to 29th of July 201

    A cohort study of low birth weight and health outcomes in the first year of life, Ghana.

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    OBJECTIVE: To investigate the effect of birth weight on infant mortality, illness and care seeking in rural Ghana. METHODS: Using randomized controlled trial data, we compared infants weighing 2.00-2.49, 1.50-1.99 and < 1.50 kg with non-low-birth-weight infants. We generated adjusted mortality hazard ratios (aHR), adjusted illness rate ratios (aRR) and adjusted odds ratios (aOR) for health-facility admissions and absence of care seeking for four time periods: infancy, the neonatal period, early infancy and late infancy - represented by ages of 0-364, 0-27, 28-182 and 183-364 days, respectively. FINDINGS: Among 22 906 infants, compared with non-low-birth-weight infants: (i) infants weighing 2.00-2.49, 1.50-1.99 and < 1.50 kg were about two (aHR: 2.13; 95% confidence interval, CI: 1.76-2.59), eight (aHR: 8.21; 95% CI: 6.26-10.76) and 25 (aHR: 25.38; 95% CI: 18.36-35.10) times more likely to die in infancy, respectively; (ii) those born weighing < 1.50 kg were about 48 (aHR: 48.45; 95% CI: 32.81-71.55) and eight (aHR: 8.42; 95% CI: 3.09-22.92) times more likely to die in the neonatal period and late infancy, respectively; (iii) those born weighing 1.50-1.99 kg (aRR: 1.57; 95% CI: 1.27-1.95) or < 1.50 kg (aRR: 1.58; 95% CI: 1.13-2.21) had higher neonatal illness rates; and (iv) for those born weighing 1.50-1.99 kg, care was less likely to be sought in the neonatal period (aOR: 3.30; 95% CI: 1.98-5.48) and early infancy (aOR : 1.74; 95% CI: 1.26-2.39). CONCLUSION: For low-birth-weight infants in Ghana, strategies to minimize mortality and improve care seeking are needed

    Neonatal vaccination of low birthweight infants in Ghana.

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    OBJECTIVES: Global vaccination policy advocates for identifying and targeting groups who are underserved by vaccination to increase equity and uptake. We investigated whether birth weight and other factors are determinants of neonatal BCG vaccination in order to identify infants underserved by vaccination. METHODS: We used logistic regression to calculate adjusted ORs (AORs) for the association between birth weight (categorised as non-low birth weight (NLBW) (≥2.50 kg) and low birth weight (LBW) (2-2.49 kg, 1.50-1.99 kg and 0.19). Facility-born infants were vaccinated at a mean of 6 days, suggesting that they were not vaccinated in the facility at birth but were referred for vaccination. CONCLUSIONS: LBW is a risk factor for neonatal under-vaccination, even for facility-born infants. Ensuring vaccination at facility births would substantively improve timing and equitable BCG vaccination

    Comparison of miRNA expression patterns using total RNA extracted from matched samples of formalin-fixed paraffin-embedded (FFPE) cells and snap frozen cells

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    <p>Abstract</p> <p>Background</p> <p>Archival formalin-fixed paraffin-embedded (FFPE) tissues have limited utility in applications involving analysis of gene expression due to mRNA degradation and modification during fixation and processing. This study analyzed 160 miRNAs in paired snap frozen and FFPE cells to investigate if miRNAs may be successfully detected in archival specimens.</p> <p>Results</p> <p>Our results show that miRNA extracted from FFPE blocks was successfully amplified using Q-RT-PCR. The levels of expression of miRNA detected in total RNA extracted from FFPE were higher than that extracted from snap frozen cells when the quantity of total RNA was identical. This phenomenon is most likely explained by the fact that larger numbers of FFPE cells were required to generate equivalent quantities of total RNA than their snap frozen counterparts.</p> <p>Conclusion</p> <p>We hypothesise that methylol cross-links between RNA and protein which occur during tissue processing inhibit the yield of total RNA. However, small RNA molecules appear to be less affected by this process and are recovered more easily in the extraction process. In general miRNAs demonstrated reliable expression levels in FFPE compared with snap frozen paired samples, suggesting these molecules might prove to be robust targets amenable to detection in archival material in the molecular pathology setting.</p

    Neurotrophins Regulate Bone Marrow Stromal Cell IL-6 Expression through the MAPK Pathway

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    The host's response to infection is characterized by altered levels of neurotrophins and an influx of inflammatory cells to sites of injured tissue. Progenitor cells that give rise to the differentiated cellular mediators of inflammation are derived from bone marrow progenitor cells where their development is regulated, in part, by cues from bone marrow stromal cells (BMSC). As such, alteration of BMSC function in response to elevated systemic mediators has the potential to alter their function in biologically relevant ways, including downstream alteration of cytokine production that influences hematopoietic development.In the current study we investigated BMSC neurotrophin receptor expression by flow cytometric analysis to determine differences in expression as well as potential to respond to NGF or BDNF. Intracellular signaling subsequent to neurotrophin stimulation of BMSC was analyzed by western blot, microarray analysis, confocal microscopy and real-time PCR. Analysis of BMSC Interleukin-6 (IL-6) expression was completed using ELISA and real-time PCR.BMSC established from different individuals had distinct expression profiles of the neurotrophin receptors, TrkA, TrkB, TrkC, and p75(NTR). These receptors were functional, demonstrated by an increase in Akt-phosphorylation following BMSC exposure to recombinant NGF or BDNF. Neurotrophin stimulation of BMSC resulted in increased IL-6 gene and protein expression which required activation of ERK and p38 MAPK signaling, but was not mediated by the NFkappaB pathway. BMSC response to neurotrophins, including the up-regulation of IL-6, may alter their support of hematopoiesis and regulate the availability of inflammatory cells for migration to sites of injury or infection. As such, these studies are relevant to the growing appreciation of the interplay between neurotropic mediators and the regulation of hematopoiesis

    Effect of BRAF(V600E )mutation on transcription and post-transcriptional regulation in a papillary thyroid carcinoma model

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    BACKGROUND: microRNAs (miRNAs) are a group of non-coding single stranded RNAs measuring approximately 22 nucleotides in length that have been found to control cell growth, differentiation and apoptosis. They negatively regulate target genes and have recently been implicated in tumourigenesis. Furthermore, miRNA expression profiling correlates with various cancers, with these genes thought to act as both tumour suppressors and oncogenes. Recently, a point mutation in the BRAF gene leading to a V600E substitution has been identified as the most common genetic change in papillary thyroid carcinoma (PTC) occurring in 29–69% of cases. This mutation leads to aberrant MAPK activation that is implicated in tumourigenesis. AIM: The aim of this study was to identify the effect that BRAF oncogene has on post-transcriptional regulation in PTC by using microRNA analysis. RESULTS: A unique miRNA expression signature differentiated between PTC cell lines with BRAF mutations and a normal thyroid cell line. 15 miRNAs were found to be upregulated and 23 miRNAs were downregulated. Several of these up/down regulated miRNAs may be involved in PTC pathogenesis. miRNA profiling will assist in the elucidation of disease pathogenesis and identification biomarkers and targets

    Improved RNA quality and TaqMan® Pre-amplification method (PreAmp) to enhance expression analysis from formalin fixed paraffin embedded (FFPE) materials

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    <p>Abstract</p> <p>Background</p> <p>Archival formalin-fixed paraffin-embedded (FFPE) tissues represent an abundant source of clinical specimens; however their use is limited in applications involving analysis of gene expression due to RNA degradation and modification during fixation and processing. This study improved the quality of RNA extracted from FFPE by introducing a heating step into the selected extraction protocols. Further, it evaluated a novel pre-amplification system (PreAmp) designed to enhance expression analysis from tissue samples using assays with a range of amplicon size (62–164 bp).</p> <p>Results</p> <p>Results from the Bioanalyzer and TaqMan<sup>® </sup>data showed improvement of RNA quality extracted using the modified protocols from FFPE. Incubation at 70°C for 20 minutes was determined to be the best condition of those tested to disrupt cross-links while not compromising RNA integrity. TaqMan<sup>® </sup>detection was influenced by master mix, amplicon size and the incorporation of a pre-amplification step. TaqMan<sup>® </sup>PreAmp consistently achieved decreased C<sub>T </sub>values in both snap frozen and FFPE aliquots compared with no pre-amplification.</p> <p>Conclusion</p> <p>Modification to extraction protocols has facilitated procurement of RNA that may be successfully amplified using QRT-PCR. TaqMan<sup>® </sup>PreAmp system is a robust and practical solution to limited quantities of RNA from FFPE extracts.</p

    Implementing Outcomes-Based Managed Entry Agreements for Rare Disease Treatments:Nusinersen and Tisagenlecleucel

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    Enthusiasm for the use of outcomes-based managed entry agreements (OBMEAs) to manage uncertainties apparent at the time of appraisal/pricing and reimbursement of new medicines has waned over the past decade, as challenges in establishment, implementation and re-appraisal have been identified. With the recent advent of innovative treatments for rare diseases that have uncertainties in the clinical evidence base, but which could meet a high unmet need, there has been renewed interest in the potential of OBMEAs. The objective of this research was to review the implementation of OBMEAs for two case studies across countries in the European Union, Australia and Canada, to identify good practices that could inform development of tools to support implementation of OBMEAs. To investigate how OBMEAs are being implemented with rare disease treatments, we collected information from health technology assessment/payer experts in countries that had implemented OBMEAs for either nusinersen in spinal muscular atrophy or tisagenlecleucel in two cancer indications. Operational characteristics of the OBMEAs that were publicly available were documented. Then, the experts discussed issues in implementing these OBMEAs and specific approaches taken to overcome challenges. The OBMEAs identified were based on individual outcomes to ensure appropriate use, manage continuation of treatment and in two cases linked to payment schedules, or they were population based, coverage with evidence development. For nusinersen, population-based OBMEAs are documented in Belgium, England and the Netherlands and individual-based schemes in Bulgaria, Ireland, Italy and Lithuania. For tisagenlecleucel, there were population-based schemes in Australia, Belgium, England and France and individual-based schemes in Italy and Spain. Comparison of the OBMEA constructs showed some clear published frameworks and clarity of the uncertainties to be addressed that were similar across countries. Agreements were generally made between the marketing authorisation holder and the payer with involvement of expert physicians. Only England and the Netherlands involved patients. Italy used its long-established, national, web-based, treatment-specific data collection system linked to reimbursement and Spain has just developed such a national treatment registry system. Other countries relied on a variety of data collection systems (including clinical registries) and administrative data. Durations of agreements varied for these treatments as did processes for interim reporting. The processes to ensure data quality, completeness and sufficiency for re-analysis after coverage with evidence development were not always clear, neither were analysis plans. These case studies have shown that important information about the constructs of OBMEAs for rare disease treatments are publicly available, and for some jurisdictions, interim reports of progress. Outcomes-based managed entry agreements can play an important role not only in reimbursement, but also in treatment optimisation. However, they are complex to implement and should be the exception and not the rule. More recent OBMEAs have developed document covenants among stakeholders or electronic systems to provide assurances about data sufficiency. For coverage with evidence development, there is an opportunity for greater collaboration among jurisdictions to share processes, develop common data collection agreements, and share interim and final reports. The establishment of an international public portal to host such reports would be particularly valuable for rare disease treatments

    Effect of ret/PTC 1 rearrangement on transcription and post-transcriptional regulation in a papillary thyroid carcinoma model

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    BACKGROUND: microRNAs (miRNAs) are a group of non-coding single stranded RNAs measuring approximately 22 nt in length that have been found to control cell growth, differentiation and apoptosis. miRNAs negatively regulate their target genes and recently have been implicated in tumourigenesis. Furthermore, miRNA expression profiling correlates with various cancers, with these genes thought to act as both tumour suppressors and oncogenes. ret/PTC 1 is an oncogene with constitutive kinase activity implicated in the development of papillary thyroid carcinoma (PTC). This rearrangement leads to aberrant MAPK activation that is implicated in PTC tumourigenesis. AIM: The aim of this study was to identify the effect that ret/PTC 1 has on transcription and post-transcriptional regulation in PTC by using DNA microarray and microRNA analysis. RESULTS: DNA microarray analysis revealed a group of genes differentially expressed between normal thyroid cell lines and those harbouring a ret/PTC 1 rearrangement. Furthermore, a unique miRNA expression signature differentiated between PTC cell lines with ret/PTC 1 and a normal thyroid cell line. 21 miRNAs showed significant overexpression and 14 miRNAs showed underexpression in these cell lines when compared to normal thyroid. Several of these up/down regulated miRNAs may be involved in PTC pathogenesis
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