1,720,979 research outputs found
Application of a fluorescent dual stain to assess decontamination of tissue protein and prion amyloid from surgical stainless steel during simulated washer-disinfector cycles
No full textCurrent World Health Organization guidelines pertaining to the reprocessing of surgical instruments in the face of potential iatrogenic transmission of Creutzfeldt-Jakob disease (iCJD) are incompatible for the vast majority of devices. This has led to the advent of a range of new decontamination measures. Even without the implementation of these new procedures, the incidence of proven iCJD through surgery remains low. In this study, existing decontamination processes in sterile service departments have been evaluated using simulated washer-disinfector cycles on surgical grade stainless steel wires inoculated with ME7 scrapie homogenate. The consequence of varying the soil drying times and choice of cycle pre-treatment on prion removal were evaluated. Assessment of residual contamination at each cycle phase was carried out with the application of a sensitive fluorescent staining procedure to identify both total protein and prion-associated amyloid. The study confirmed that immediate reprocessing following contamination was beneficial during the pre-treatment phase with either an enzymatic or pre-soak wetting agent. Final total protein levels at the end of the cycles, were not significantly different from those where the soil was allowed to dry. In addition, cycles involving a pre-treatment with either an enzymatic cleaner or pre-soak, whether the soil was allowed to dry or not, showed complete removal of detectable prion amyloid. The results suggest that current decontamination procedures, combined with immediate processing of surgical instruments, have the potential to be highly effective alone at reducing the risk of surgical transmission of CJ
Efficacy of humidity retention bags for the reduced adsorption and improved cleaning of tissue proteins including prion-associated amyloid to surgical stainless steel surfaces
No full textIncreasing drying time adversely affects attachment of tissue proteins and prion-associated amyloid to surgical stainless steel, and reduces the efficacy of commercial cleaning chemistries. This study tested the efficacy of commercial humidity retention bags to reduce biofouling on surgical stainless steel and to improve subsequent cleaning. Surgical stainless steel surfaces were contaminated with ME7-infected brain homogenates and left to dry for 15 to 1,440 min either in air, in dry polythene bags or within humidity retention bags. Residual contamination pre/post cleaning was analysed using Thioflavin T/SYPRO Ruby dual staining and microscope analysis. An increase in biofouling was observed with increased drying time in air or in sealed dry bags. Humidity retention bags kept both protein and prion-associated amyloid minimal across the drying times both pre- and post-cleaning. Therefore, humidity bags demonstrate a cheap, easy to implement solution to improve surgical instrument reprocessing and to potentially reduce associated hospital acquired infections
Sensitive microscopic quantification of surface-bound prion infectivity for the assessment of surgical instrument decontamination procedures
No full textBackground: pathogenic prions (PrPSc) are amyloid-rich hydrophobic proteins which bind avidly to surgical surfaces and represent some of the most difficult targets during the reprocessing of reusable surgical instruments. In-vitro methods to amplify and detect the presence of otherwise undetectable prion contamination are available, but they do not measure associated infectivity. Most of these methods rely on the use of proteinase K, however this can lead to the loss of a substantial portion of PrPSc, potentially producing false negatives. Aim: to develop a sensitive in-situ method without proteinase treatment for the dynamic quantification of amyloid accumulation in N2a #58 cells following 22L-prion infection from infected tissues and spiked stainless-steel surfaces. Methods: we spiked cultures of N2a #58 cells with the 22L prion strain in solution or dried on stainless-steel wires and directly measured the accumulation of prion amyloid aggregates over several passages using highly sensitive fluorescence microscopy.Findings: we demonstrated a 10-log dynamic range using our method to test residual prion infectivity, that was validated to show variable decontamination efficacy against prions from commercially available cleaning chemistries.Conclusions: the new cell-based infectivity method presented here avoids partial or possibly total proteinase K digestion of PrPSc in samples for greater sensitivity, in addition to low cost, no ethical concerns, and adaptability to detect different prion strains. This method can be used to test cleaning chemistries' efficacy with greater sensitivity than measuring total residual proteins, which may not correlate with residual prion infectivity.</p
Erratum to Acquisition of proteinaceous contamination through the handling of surgical instruments by hospital staff in sterile service departments (Journal of Infection Prevention, (2009), 10, (106-111), 10.1177/1757177409105073)
No full textAcquisition of proteinaceous contamination through the handling of surgical instruments by hospital staff in sterile service departments
No full textUsing Episcopic Differential Interference Contrast (EDIC) microscopy, this study has investigated the potential reapplication of proteinaceous contamination onto surgical instruments following a washer-disinfector cycle through the handling of staff within the clean room. The deposition of 0.51 ng/mm2 of protein onto surgical grade stainless steel by one finger print alone has been demonstrated. Moreover, using a previously described contamination index, a 5 to 10-fold increase in protein present on surgical instruments was noted following handling by clean-room staff under current departmental practices, relative to instruments handled by staff wearing gloves. While unlikely to pose a direct risk to patient health, subsequent sterilisation will fix protein to an instrument surface thereby decreasing the effectiveness of further decontamination cycles. Current guidelines make no recommendations surrounding the use of gloves by staff working within the clean room. However it is clear that this matter must be reviewed to limit the unnecessary transference of protein to surgical instruments
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
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