1,720,956 research outputs found
Innovating indwelling catheter design to counteract urinary tract infection
No full textBackground and objective: bacteriuria is anticipated in long-term indwelling catheter (IDC) use, and urinary tract infections (UTIs) and related issues are common. Defence mechanisms against infection are undermined by the presence of a Foley catheter, and adjustments to design could influence UTI risk.Methods: we reviewed the various aspects of IDCs and ureteric stent designs to discuss potential impact on UTI risk.Key findings and limitations: design adaptations have focussed on reducing the sump of undrained urine, potential urinary tract trauma, and bacterial adherence. Experimental and computational studies on ureteral stents found an interplay between urine flow, bacterial microcolony formation, and accumulation of encrusting particles. The most critical regions for biofilm and crystal accumulation are associated with low shear stress. The full drainage system is the functioning unit, not just the IDC in isolation. This means reliably keeping the drainage system closed and considering whether a valve is preferred to a collection bag. Other developments may include one-way valves, obstacles to “bacterial swimming”, and ultrasound techniques. Preventing or clearing IDC blockage can exploit access via the lumen or retaining balloon. Progress in computational fluid dynamics, energy delivery, and soft robotics may increase future options. Clinical data on the effectiveness of IDC design features are lacking, which is partly due to reliance on proxy measures and the challenges of undertaking trials.Conclusions and clinical implications: design changes are legitimate lines of development, but are only indirect for UTI prevention. Modifications may be advantageous, but might potentially bring problems in other ways. Education of health care professionals can improve UTIs and should be prioritised.Patient summary: catheters used to help bladder drainage can cause urinary infections, and improvements in design might reduce the risk. Several approaches are described in this review. However, proving that these approaches work is a challenge. Training professionals in the key aspects of catheter care is important
Novel insights into the Proteus mirabilis crystalline biofilm using real-time imaging
No full textThe long-term use of indwelling catheters results in a high risk from urinary tract infections (UTI) and blockage. Blockages often occur from crystalline deposits, formed as the pH rises due to the action of urease-producing bacteria; the most commonly found species being Proteus mirabilis. These crystalline biofilms have been found to develop on all catheter materials with P. mirabilis attaching to all surfaces and forming encrustations. Previous studies have mainly relied on electron microscopy to describe this process but there remains a lack of understanding into the stages of biofilm formation. Using an advanced light microscopy technique, episcopic differential interference contrast (EDIC) microscopy combined with epifluorescence (EF), we describe a non-destructive, non-contact, real-time imaging method used to track all stages of biofilm development from initial single cell attachment to complex crystalline biofilm formation. Using a simple six-well plate system, attachment of P. mirabilis (in artificial urine) to sections of silicone and hydrogel latex catheters was tracked over time (up to 24 days). Using EDIC and EF we show how initial attachment occurred in less than 1 h following exposure to P. mirabilis. This was rapidly followed by an accumulation of an additional material (indicated to be carbohydrate based using lectin staining) and the presence of highly elongated, motile cells. After 24 h exposure, a layer developed above this conditioning film and within 4 days the entire surface (of both catheter materials) was covered with diffuse crystalline deposits with defined crystals embedded. Using three-dimensional image reconstruction software, cells of P. mirabilis were seen covering the crystal surfaces. EDIC microscopy could resolve these four components of the complex crystalline biofilm and the close relationship between P. mirabilis and the crystals. This real-time imaging technique permits study of this complex biofilm development with no risk of artefacts due to sample manipulation. A full understanding of the stages and components involved in crystalline encrustation formation will aid in the development of new protocols to manage and ultimately prevent catheter blockage
Intermittent catheterisation for long-term bladder management (abridged Cochrane Review)
No full textAims: to review the evidence on strategies to reduce UTI, other complications or improve satisfaction in intermittent catheter (IC) users by comparing: (1) one catheter design, material or technique versus another; (2) sterile technique versus clean; or (3) single-use (sterile) or multiple-use (clean) catheters.Methods: we searched Cochrane Incontinence Group Specialised Trials Register, MEDLINE, EMBASE, CINAHL, ERIC, reference lists, and conference proceedings to November 2013. We contacted other investigators for unpublished data or clarification. Trial screening, assessment and data abstraction were all in accordance with the Cochrane handbook.Results: thirty one trials (13 RCTs and 18 randomized crossover trials), addressed the inclusion criteria comparing method or design and UTI/bacteriuria, other complications or participant assessed outcomes. Studies varied widely in follow-up, UTI definition and attrition; in some, data could not be combined. Where there were data, confidence intervals were wide and hence clinically important differences could neither be reliably identified nor ruled out.Conclusions: current research evidence is weak and design issues are significant. It has not yet been established whether incidence of UTI, other complications such as haematuria, or user satisfaction are affected by sterile or clean technique, coated or uncoated catheters, single or multiple-use catheters or by any other strategy. For people using IC, choice of catheter will depend on personal preference, cost, portability, and ease of use. Individuals should discuss the catheter options with their healthcare practitioner. Cost-effectiveness analysis and use of the standard definition of UTI are essential in any proposed clinical tria
Development and psychometric evaluation of the ICIQ-LTCqol: a self-report quality of life questionnaire for long-term indwelling catheter users
Full text linkAims: Long-term indwelling catheterisation may affect health related quality of life, but clinical assessment and monitoring of people with indwelling catheters is poorly recorded because there are no validated measures to capture these criteria. In this paper, we describe the development of the ICIQ-Long Term Catheter quality of life (ICIQ-LTCqol), one of the modules of the ICIQ series, an international project to standardise assessment of lower pelvic dysfunction: www.iciq.net.Methods: In-depth interviews were conducted with 27 catheter-users and 4 informal carers and cognitive debriefing with a further 31 catheter-users and clinical experts to evaluate clarity and comprehensiveness. The draft 44 item questionnaire was then sent by post to 893 long-term catheter-users; the 370 completed questionnaires were used to test content validity, test re-test reliability and internal consistency (Cronbach ? coefficient). Factor analysis alongside expert opinion was used to formulate the final questionnaire of 16 items. This was then sent by post to another 438 long-term catheter-users to evaluate domain scores.Results: The final questionnaire consists of two scored domains: catheter function and concern (9 items) and lifestyle impact (3 items) and four standalone items, relating to pads, pain, sexual activity and bladder spasm. Levels of missing data are good (mean 3.6%) with moderate to good agreement and acceptable internal consistency (Cronbach's alpha 0.76 and 0.74 for each domain respectively), suggesting acceptability and stability of the questionnaire.Conclusion: The ICIQ-LTCqol is a psychometrically robust self-report questionnaire for the clinical assessment and evaluation of health related quality of life for long-term catheter users. Neurourol. Urodynam. 9999:XX–XX, 2015. © 2015 Wiley Periodicals, Inc
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
- …
