2,257 research outputs found
The regulation of RNA polymerase III transcription by protein kinase CK2
In order for cells to proliferate, a certain size has to be reached, which depends primarily on the rate of translation. RNA polymerase (pol) III plays a key role in protein synthesis by catalysing the production of small, untranslated RNA molecules such as transfer (tRNA) and 5S ribosomal RNA (5S rRNA). Indeed, recent evidence suggests that tRNAiMet production is limiting for translation and proliferation in some cell types. Therefore, the rate of pol III transcription plays a fundamental role in cellular growth and proliferation. Regulation of pol III output is mediated via a number of different mechanisms that can alter the activities of the transcription factors which are responsible for directing pol III transcription. Work presented in this thesis aimed at investigating the mechanisms behind the regulation of pol III transcription by the protein kinase CK2
A proteomic approach to identify endosomal cargoes controlling cancer invasiveness
We have previously shown that Rab17 - a small GTPase associated with epithelial polarity - is specifically suppressed by ERK2 signalling to promote an invasive phenotype. However, the mechanisms through which Rab17 loss permits invasiveness, and the endosomal cargoes that are responsible for mediating this are not known. Using quantitative mass spectrometry-based proteomics, we have found that knockdown of Rab17 leads to highly selective reduction in the cellular levels of a v-SNARE (Vamp8). Moreover, proteomics and immunofluorescence indicate that Vamp-8 is associated with Rab17 at late endosomes. Reduced levels of Vamp8 promote transition between ductal carcinoma in situ (DCIS) and a more invasive phenotype. We developed an unbiased proteomic approach to elucidate the complement of receptors that redistributes between endosomes and the plasma membrane, and have pin-pointed neuropilin-2 (NRP2) as a key pro-invasive cargo of Rab17/Vamp8-regulated trafficking. Indeed, reduced Rab17 or Vamp8 levels lead to increased mobilisation of NRP2-containing late endosomes and upregulated cell surface expression of NRP2. Finally, we show that NRP2 is required for the basement membrane disruption which accompanies transition between DCIS and a more invasive phenotype
Paediatric distal radial fracture manipulation: Multicentre analysis of process times
Background: Children with simple radial fractures requiring manipulation are conventionally admitted for manipulation under general anaesthesia. On the assumption that children (and their parents) wish to spend as little time in hospital as possible, a study was undertaken to explore the experience of children with distal radial fractures admitted for general anaesthesia. Methods: A retrospective analysis was performed of the time taken from arrival at the emergency department (ED) to general anaesthesia and the time taken from arrival at the ED to hospital discharge in three centres in south-west England: the Bristol Children's Hospital, Derriford (Plymouth) Hospital and the Royal Devon & Exeter Hospital. Results: The median wait for general anaesthesia was >8 h and the median wait from ED admission to discharge was >21 h. This compares with a typical arrival to discharge time for paediatric procedural sedation of 4-5 h in the ED of the Royal Devon & Exeter Hospital. Conclusions: Given the assumption that children (and their parents) wish to spend as little time in hospital as possible, there appears to be a role for procedural sedation in the ED for this group of children, with a significantly reduced turnaround time anticipated
Solvent inhibition in the liquid-phase catalytic oxidation of 1,4-butanediol: understanding the catalyst behaviour from NMR relaxation time measurements
Catalytic reaction studies and Nuclear Magnetic Resonance (NMR) relaxation time measurements have been compared to study the influence of competitive adsorption of reactant and solvent on catalytic conversion. The reaction chosen is the aerobic catalytic oxidation of 1,4-butanediol in methanol over different supported-metal catalysts. From the NMR T1/T2 ratio, where T1 is the longitudinal and T2 the transverse spin relaxation time, the relative affinity of reactant and solvent for different catalytic surfaces is determined. The catalysts with the lowest activity show a preferential surface affinity for the solvent compared to the reactant. Conversely, the catalyst with the highest activity shows a preferential surface affinity for the reactant compared to the solvent. Significantly, Ru/SiO2, which is totally inactive for the oxidation of 1,4-butanediol, exhibited a lower T1/T2 ratio (surface affinity) for 1,4-butanediol (reactant) than for a âweakly-interactingâ alkane, indicating a very poor surface affinity for the diol functionality. The results provide direct evidence of the importance of the adsorbate-adsorbent interactions on catalyst activity in liquid-phase oxidations and indicate that the competitive adsorption of the solvent plays an important role in these reactions. This work demonstrates that NMR relaxation time analysis is a powerful method for comparing adsorption of liquids in porous catalysts, providing valuable information on the affinity of different chemical species for a catalyst surface. Moreover, the results demonstrate that NMR relaxation time measurements can be used not only to guide selection of solvent for use with a specific catalyst, but also selection of the catalyst itself. The results suggest that this method may be used to predict catalyst behaviour, enabling improved design and optimisation of heterogeneous catalytic processes
A comparison of a structured home-based rehabilitation programme with conventional supervised pulmonary rehabilitation:A randomised non-inferiority trial
Background: Standardised home-based pulmonary rehabilitation (PR) programmes offer an alternative model to centre-based supervised PR for which uptake is currently poor. We determined if a structured home-based unsupervised PR programme was non-inferior to supervised centre-based PR for participants with COPD.
Methods: A total of 287 participants with COPD who were referred to PR (187 male, mean (SD) age 68 (8.86) years, FEV1% predicted 48.34 (17.92)) were recruited. They were randomised to either centre-based PR or a structured unsupervised home-based PR programme including a hospital visit with a healthcare professional trained in motivational interviewing, a self-management manual and two telephone calls. Fifty-eight (20%) withdrew from the centre-based group and 51 (18%) from the home group. The primary outcome was dyspnoea domain in the chronic respiratory disease questionnaire (Chronic Respiratory Questionnaire Self-Report; CRQ-SR) at 7âweeks. Measures were taken blinded. We undertook a modified intention-to-treat (mITT) complete case analysis, comparing groups according to original random allocation and with complete data at follow-up. The non-inferiority margin was 0.5 units.
Results: There was evidence of significant gains in CRQ-dyspnoea at 7âweeks in both home and centre-based groups. There was inconclusive evidence that home-based PR was non-inferior to PR in dyspnoea (mean group difference, mITT: â0.24, 95%âCI â0.61 to 0.12, p=0.18), favouring the centre group at 7âweeks.
Conclusions: The standardised home-based programme provides benefits in dyspnoea. Further evidence is needed to definitively determine if the health benefits of the standardised home-based programme are non-inferior or equivalent to supervised centre-based rehabilitation
Epstein-Barr virus-encoded EBNA1 enhances RNA polymerase III-dependent EBER expression through induction of EBER-associated cellular transcription factors
Background
Epstein-Barr Virus (EBV)-encoded RNAs (EBERs) are non-polyadenylated RNA molecules transcribed from the EBV genome by RNA polymerase III (pol III). EBERs are the most abundant viral latent gene products, although the precise mechanisms by which EBV is able to achieve such high levels of EBER expression are not fully understood. Previously EBV has been demonstrated to induce transcription factors associated with EBER expression, including pol III transcription factors and ATF-2. We have recently demonstrated that EBV-encoded nuclear antigen-1 (EBNA1) induces cellular transcription factors, and given these findings, we investigated the role of EBNA1 in induction of EBER-associated transcription factors.
Results
Our data confirm that in epithelial cells EBNA1 can enhance cellular pol III transcription. Transient expression of EBNA1 in Ad/AH cells stably expressing the EBERs led to induction of both EBER1 and EBER2 and conversely, expression of a dominant negative EBNA1 led to reduced EBER expression in EBV-infected Ad/AH cells. EBNA1 can induce transcription factors used by EBER genes, including TFIIIC, ATF-2 and c-Myc. A variant chromatin precipitation procedure showed that EBNA1 is associated with the promoters of these genes but not with the promoters of pol III-transcribed genes, including the EBERs themselves. Using shRNA knock-down, we confirm the significance of both ATF-2 and c-Myc in EBER expression. Further, functional induction of a c-Myc fusion protein led to increased EBER expression, providing c-Myc binding sites upstream of EBER1 were intact. In vivo studies confirm elevated levels of the 102 kD subunit of TFIIIC in the tumour cells of EBV-positive nasopharyngeal carcinoma biopsies.
Conclusions
Our findings reveal that EBNA1 is able to enhance EBER expression through induction of cellular transcription factors and add to the repertoire of EBNA1's transcription-regulatory properties
An integrated general practice and pharmacy-based intervention to promote the use of appropriate preventive medications among individuals at high cardiovascular disease risk: protocol for a cluster randomized controlled trial
Background: Cardiovascular diseases (CVD) are responsible for significant morbidity, premature mortality, and economic burden. Despite established evidence that supports the use of preventive medications among patients at high CVD risk, treatment gaps remain. Building on prior evidence and a theoretical framework, a complex intervention has been designed to address these gaps among high-risk, under-treated patients in the Australian primary care setting. This intervention comprises a general practice quality improvement tool incorporating clinical decision support and audit/feedback capabilities; availability of a range of CVD polypills (fixed-dose combinations of two blood pressure lowering agents, a statin ± aspirin) for prescription when appropriate; and access to a pharmacy-based program to support long-term medication adherence and lifestyle modification.
Methods: Following a systematic development process, the intervention will be evaluated in a pragmatic cluster randomized controlled trial including 70 general practices for a median period of 18 months. The 35 general practices in the intervention group will work with a nominated partner pharmacy, whereas those in the control group will provide usual care without access to the intervention tools. The primary outcome is the proportion of patients at high CVD risk who were inadequately treated at baseline who achieve target blood pressure (BP) and low-density lipoprotein cholesterol (LDL-C) levels at the study end. The outcomes will be analyzed using data from electronic medical records, utilizing a validated extraction tool. Detailed process and economic evaluations will also be performed.
Discussion: The study intends to establish evidence about an intervention that combines technological innovation with team collaboration between patients, pharmacists, and general practitioners (GPs) for CVD prevention.
Trial registration: Australian New Zealand Clinical Trials Registry ACTRN1261600023342
Stillbirth is associated with perceived alterations in fetal activity - findings from an international case control study
Background Stillbirth after 28 weeks gestation affects between 1.3â8.8 per 1000 births in high-income countries. The majority of stillbirths in this setting occur in women without established risk factors. Identification of risk factors which could be identified and managed in pregnancy is a priority in stillbirth prevention research. This study aimed to evaluate womenâs experiences of fetal movements and how these relate to stillbirth. Methods An international internet-based caseâcontrol study of women who had a stillbirth â„28 weeksâ gestation within 30 days prior to completing the survey (n = 153) and women with an ongoing pregnancy or a live born child (n = 480). The online questionnaire was developed with parent stakeholder organizations using a mixture of categorical and openâended responses and Likert scales. Univariate and multiple logistic regression was used to determine crude (unadjusted) and adjusted odds ratios (aOR) with 95% confidence intervals (CI). Summative content analysis was used to analyse free text responses. Results Women whose pregnancy ended in stillbirth were less likely to check fetal movements (aOR 0.54, 95% CI 0.35â0.83) and were less likely to be told to do so by a health professional (aOR 0.55, 95% CI 0.36â0.86). Pregnancies ending in stillbirth were more frequently associated with significant abnormalities in fetal movements in the preceding two weeks; this included a significant reduction in fetal activity (aOR 14.1, 95% CI 7.27â27.45) or sudden single episode of excessive fetal activity (aOR 4.30, 95% CI 2.25â8.24). Cases described their perception of changes in fetal activity differently to healthy controls e.g. vigorous activity was described as âfranticâ, âwildâ or âcrazyâ compared to âpowerfulâ or âstrongâ. Conclusions Alterations in fetal activity are associated with increased risk of stillbirth. Pregnant women should be educated about awareness of fetal activity and reporting abnormal activity to health professionals
Context, mechanisms and outcomes in end of life care for people with advanced dementia
yesBackground: The majority of people with dementia in the UK die in care homes. The quality of end of life care in
these environments is often suboptimal. The aim of the present study was to explore the context, mechanisms and
outcomes for providing good palliative care to people with advanced dementia residing in UK care homes from
the perspective of health and social care providers.
Method: The design of the study was qualitative which involved purposive sampling of health care professionals to
undertake interactive interviews within a realist framework. Interviews were completed between September 2012
and October 2013 and were thematically analysed and then conceptualised according to context, mechanisms and
outcomes. The settings were private care homes and services provided by the National Health Service including
memory clinics, mental health and commissioning services in London, United Kingdom. The participants included
14 health and social care professionals including health care assistants, care home managers, commissioners for
older adultsâ services and nursing staff.
Results: Good palliative care for people with advanced dementia is underpinned by the prioritisation of
psychosocial and spiritual care, developing relationships with family carers, addressing physical needs including
symptom management and continuous, integrated care provided by a multidisciplinary team. Contextual factors
that detract from good end of life care included: an emphasis on financial efficiency over person-centred care; a
complex health and social care system, societal and family attitudes towards staff; staff training and experience,
governance and bureaucratisation; complexity of dementia; advance care planning and staff characteristics.
Mechanisms that influence the quality of end of life care include: level of health care professionalsâ confidence,
family uncertainty about end of life care, resources for improving end of life care and supporting families, and
uncertainty about whether dementia specific palliative care is required.
Conclusions: Contextual factors regarding the care home environment may be obdurate and tend to negatively
impact on the quality of end of life dementia care. Local level mechanisms may be more amenable to
improvement. However, systemic changes to the care home environment are necessary to promote consistent,
equitable and sustainable high quality end of life dementia care across the UK care home secto
Linking complex forest fuel structure and fire behaviour at fine scales
Abstract. Improved fire management of savannas and open woodlands requires better understanding of the fundamental connection between fuel heterogeneity, variation in fire behaviour and the influence of fire variation on vegetation feedbacks. In this study, we introduce a novel approach to predicting fire behaviour at the submetre scale, including measurements of forest understorey fuels using ground-based LIDAR (light detection and ranging) coupled with infrared thermography for recording precise fire temperatures. We used ensemble classification and regression trees to examine the relationships between fuel characteristics and fire temperature dynamics. Fire behaviour was best predicted by characterising fuelbed heterogeneity and continuity across multiple plots of similar fire intensity, where impacts from plot-to-plot variation in fuel, fire and weather did not overwhelm the effects of fuels. The individual plot-level results revealed the significance of specific fuel types (e.g. bare soil, pine leaf litter) as well as the spatial configuration of fire. This was the first known study to link the importance of fuelbed continuity and the heterogeneity associated with fuel types to fire behaviour at metre to submetre scales and provides the next step in understanding the complex responses of vegetation to fire behaviour
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