226 research outputs found

    Outcomes of primary percutaneous coronary intervention for patients with previous coronary artery bypass grafting presenting with STsegment elevation myocardial infarction

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    BACKGROUND: There are limited data on outcomes of patients with previous coronary artery bypass grafting (CABG) presenting acutely as ST-segment elevation myocardial infarction (STEMI) and undergoing primary percutaneous coronary intervention (PPCI). OBJECTIVES: To compare outcomes in STEMI patients undergoing PPCI with or without previous CABG surgery. METHODS: An all-comer single-centre observational registry from a cardiothoracic centre in UK. All consecutive patients presenting for PPCI between 2007 and 2012 were included. Electronic records were used to extract relevant information. Mortality data were obtained from the Office of National Statistics. Overall median follow-up period was 1.7 years (intraquartile range 0.9-2.5). RESULTS: Complete data were available for 2133 (97%) patients. 47-patients had previous history of CABG. Out of these, the infarct related artery (IRA) was native vessel in 22 and graft in 25 patients. Post re-vascularization TIMI flow was inferior in CABG cohort (<TIMI 3 flow in 17% vs. 10%, p=0.012) and they were less likely to achieve acute reperfusion (TIMI 0 in 9% vs. 3%, p=0012). In-hospital-mortality was not different in both groups (2%vs.4%, p=0.23). 30-day (HR 0.54; 95%CI 0.17-1.73; P=0.301), 1-year-mortality (HR 0.77; 95%CI 0.31-1.87; P=0.56) and over a median follow-up of 1.7 years (HR 1.1; 95%CI 0.54-2.27; P=0.79) were also not different. CONCLUSION: Patients presenting with STEMI to PPCI service with history of CABG are less likely to achieve acute reperfusion and have worse angiographic outcomes. Post PPCI, the prior CABG patients do not seem to have worse shortterm and long-term prognosis

    Structural investigation of MOVPE-Grown GaAs on Ge by X-ray techniques

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    The selection of appropriate characterisation methodologies is vital for analysing and comprehending the sources of defects and their influence on the properties of heteroepitaxially grown III-V layers. In this work we investigate the structural properties of GaAs layers grown by Metal-Organic Vapour Phase Epitaxy (MOVPE) on Ge substrates – (100) with 6⁰ offset towards – under various growth conditions. Synchrotron X-ray topography (SXRT) is employed to investigate the nature of extended linear defects formed in GaAs epilayers. Other X-ray techniques, such as reciprocal space mapping (RSM) and triple axis ω-scans of (00l)-reflections (l = 2, 4, 6) are used to quantify the degree of relaxation and presence of antiphase domains (APDs) in the GaAs crystals. The surface roughness is found to be closely related to the size of APDs formed at the GaAs/Ge heterointerface, as confirmed by X-ray diffraction (XRD), as well as atomic force microscopy (AFM), and transmission electron microscopy (TEM)

    Structural investigation of MOVPE-Grown GaAs on Ge by X-ray techniques

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    The selection of appropriate characterisation methodologies is vital for analysing and comprehending the sources of defects and their influence on the properties of heteroepitaxially grown III-V layers. In this work we investigate the structural properties of GaAs layers grown by Metal-Organic Vapour Phase Epitaxy (MOVPE) on Ge substrates – (100) with 6⁰ offset towards – under various growth conditions. Synchrotron X-ray topography (SXRT) is employed to investigate the nature of extended linear defects formed in GaAs epilayers. Other X-ray techniques, such as reciprocal space mapping (RSM) and triple axis ω-scans of (00l)-reflections (l = 2, 4, 6) are used to quantify the degree of relaxation and presence of antiphase domains (APDs) in the GaAs crystals. The surface roughness is found to be closely related to the size of APDs formed at the GaAs/Ge heterointerface, as confirmed by X-ray diffraction (XRD), as well as atomic force microscopy (AFM), and transmission electron microscopy (TEM)

    Transcriptional analysis of temporal gene expression in germinating Clostridium difficile 630 endospores.

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    Clostridium difficile is the leading cause of hospital acquired diarrhoea in industrialised countries. Under conditions that are not favourable for growth, the pathogen produces metabolically dormant endospores via asymmetric cell division. These are extremely resistant to both chemical and physical stress and provide the mechanism by which C. difficile can evade the potentially fatal consequences of exposure to heat, oxygen, alcohol, and certain disinfectants. Spores are the primary infective agent and must germinate to allow for vegetative cell growth and toxin production. While spore germination in Bacillus is well understood, little is known about C. difficile germination and outgrowth. Here we use genome-wide transcriptional analysis to elucidate the temporal gene expression patterns in C. difficile 630 endospore germination. We have optimized methods for large scale production and purification of spores. The germination characteristics of purified spores have been characterized and RNA extraction protocols have been optimized. Gene expression was highly dynamic during germination and outgrowth, and was found to involve a large number of genes. Using this genome-wide, microarray approach we have identified 511 genes that are significantly up- or down-regulated during C. difficile germination (p≤0.01). A number of functional groups of genes appeared to be co-regulated. These included transport, protein synthesis and secretion, motility and chemotaxis as well as cell wall biogenesis. These data give insight into how C. difficile re-establishes its metabolism, re-builds the basic structures of the vegetative cell and resumes growth

    Donor heart selection: the outcome of "unacceptable" donors

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    BACKGROUND: The decline in the number of suitable donor hearts has led to an increasing interest in the use of previously unacceptable donors. In the United Kingdom, if one centre declines a donor heart on medical grounds it may be offered to other centres. This multi-centre study aimed to evaluate the outcome of recipients of donor hearts considered medically unsuitable for transplantation by one centre that were used in other centres. METHODS: Between April 1998 and March 2003, ninety-three donor hearts (group A) were transplanted, after being considered medically unsuitable for transplantation by another centre. During the same period, 723 hearts (group B) were transplanted in the UK using donors not previously rejected. Data on the donors and recipients was obtained from the UK transplant database. Comparative analysis on the two groups was performed using SPSS 11.5 for Windows. RESULTS: The characteristics of recipients were similar in both groups. The main reasons for refusal of hearts are listed below. In most cases there was more than one reason for refusing the donor heart. We did not find significant differences in the post-operative mortality (up to 30 days), ICU and hospital stay and cardiac cause of death between the two groups. Kaplan-Meier survival curves showed no significant difference in the long-term survival, with Log Rank test = 0.30. CONCLUSION: This study demonstrates that some hearts declined on medical grounds by one centre can safely be transplanted and should be offered out nationally. The use of these hearts was useful to expand the scarce donor pool and there does not seem to be a justification for denying recipients this extra source of organs

    A multidisciplinary systematic review of the use of diagrams as a means of collecting data from research subjects: application, benefits and recommendations

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    BACKGROUND: In research, diagrams are most commonly used in the analysis of data and visual presentation of results. However there has been a substantial growth in the use of diagrams in earlier stages of the research process to collect data. Despite this growth, guidance on this technique is often isolated within disciplines. METHODS: A multidisciplinary systematic review was performed, which included 13 traditional healthcare and non-health-focused indexes, non-indexed searches and contacting experts in the field. English-language articles that used diagrams as a data collection tool and reflected on the process were included in the review, with no restriction on publication date. RESULTS: The search identified 2690 documents, of which 80 were included in the final analysis. The choice to use diagrams for data collection is often determined by requirements of the research topic, such as the need to understand research subjects' knowledge or cognitive structure, to overcome cultural and linguistic differences, or to understand highly complex subject matter. How diagrams were used for data collection varied by the degrees of instruction for, and freedom in, diagram creation, the number of diagrams created or edited and the use of diagrams in conjunction with other data collection methods. Depending on how data collection is structured, a variety of options for qualitative and quantitative analysis are available to the researcher. The review identified a number of benefits to using diagrams in data collection, including the ease with which the method can be adapted to complement other data collection methods and its ability to focus discussion. However it is clear that the benefits and challenges of diagramming depend on the nature of its application and the type of diagrams used. DISCUSSION/CONCLUSION: The results of this multidisciplinary systematic review examine the application of diagrams in data collection and the methods for analyzing the unique datasets elicited. Three recommendations are presented. Firstly, the diagrammatic approach should be chosen based on the type of data needed. Secondly, appropriate instructions will depend on the approach chosen. And thirdly, the final results should present examples of original or recreated diagrams. This review also highlighted the need for a standardized terminology of the method and a supporting theoretical framework

    Priming Picture Naming with a Semantic Task: An fMRI Investigation

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    Prior semantic processing can enhance subsequent picture naming performance, yet the neurocognitive mechanisms underlying this effect and its longevity are unknown. This functional magnetic resonance imaging study examined whether different neurological mechanisms underlie short-term (within minutes) and long-term (within days) facilitation effects from a semantic task in healthy older adults. Both short- and long-term facilitated items were named significantly faster than unfacilitated items, with short-term items significantly faster than long-term items. Region of interest results identified decreased activity for long-term facilitated items compared to unfacilitated and short-term facilitated items in the mid-portion of the middle temporal gyrus, indicating lexical-semantic priming. Additionally, in the whole brain results, increased activity for short-term facilitated items was identified in regions previously linked to episodic memory and object recognition, including the right lingual gyrus (extending to the precuneus region) and the left inferior occipital gyrus (extending to the left fusiform region). These findings suggest that distinct neurocognitive mechanisms underlie short- and long-term facilitation of picture naming by a semantic task, with long-term effects driven by lexical-semantic priming and short-term effects by episodic memory and visual object recognition mechanisms

    Evaluation of an open access echocardiography service in the Netherlands: a mixed methods study of indications, outcomes, patient management and trends

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    Background: In our region (Eastern South Limburg, The Netherlands) an open access echocardiography service started in 2002. It was the first service of this kind in The Netherlands. Our study aims were: (1) to evaluate demand for the service, participation, indications, echocardiography outcomes, and management by the general practitioner (GP); (2) to analyse changes in indications and outcomes over the years. Methods: (1) Data from GP request forms, echocardiography reports and a retrospective GP questionnaire on management (response rate 83%) of 625 consecutive patients (Dec. 2002-March 2007) were analysed cross-sectionally. (2) For the analysis of changes over the years, data from GP request forms and echocardiography reports of the first and last 250 patients that visited the service between Dec. 2002 and Feb. 2008 (n = 1001) were compared. Results: The echocardiography service was used by 81% of the regional GPs. On average, a GP referred one patient per year to the service. Intended indications for the service were dyspnoea (32%), cardiac murmur (59%), and peripheral oedema (17%). Of the other indications (22%), one-third was for evaluation of suspected left ventricular hypertrophy (LVH). Expected outcomes were left ventricular dysfunction (LVD) (43%, predominantly diastolic) and valve disease (25%). We also found a high proportion of LVH (50%). Only 24% of all echocardiograms showed no relevant disease. The GP followed the cardiologist's advice to refer the patient for further evaluation in 71%. In recent patients, more echocardiography requests were done for 'cardiac murmur' and 'other' indications, but less for 'dyspnoea'. The proportions of patients with LVD, LVH and valve disease decreased and the proportion of patients with no relevant disease increased. The number of advices by the cardiologists increased. Conclusion: Overall, GPs used the open access echocardiography service efficiently (i. e. with a high chance of finding relevant pathology), but efficiency decreased slightly over the years. To meet the needs of the GPs, indications might be widened with 'suspicion LVH'. Further specification of the indications for open access echocardiography-by defining a stepwise diagnostic approach including ECG and (NT-pro)BNP-might improve the service
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