328 research outputs found

    Accentuating patient values in shared decision-making:A mixed methods development of an online value clarification tool and communication training in the context of early phase clinical cancer trials

    Get PDF
    Objective: In the shared decision-making (SDM) process for potential early phase clinical cancer trial participation, value clarification is highly recommended. However, exploration and discussion of patient values between patients and oncologists remains limited. This study aims to develop an SDM-supportive intervention, consisting of a preparatory online value clarification tool (OnVaCT) and a communication training. Methods: The OnVaCT intervention was developed and pilot-tested by combining theoretical notions on value clarification, with interview studies with patients and oncologists, focus groups with patient representatives and oncologists, and think aloud sessions with patients, following the Medical Research Council (MRC) framework for complex interventions. These human-centered methodologies enabled a user-centered approach at every step of the development process of the intervention. Results: This study shows relevant patient values and oncologists’ perspectives on value exploration and discussion in daily practice. This has been combined with theoretical considerations into the creation of characters based on real-life experiences of patients in the OnVaCT, and how the tool is combined with a communication training for oncologists to improve SDM

    Impact of analyzing fewer image frames per segment during offline volumetric radiofrequency-based intravascular ultrasound measurements of target lesions prior to percutaneous coronary interventions

    Get PDF
    In the present study, we evaluated the impact of a 50% reduction in number of image frames (every second frame) on the analysis time and variability of offline volumetric radiofrequency-based intravascular ultrasound (RF-IVUS) measurements in target lesions prior to percutaneous coronary interventions (PCI). Volumetric RF-IVUS data of vessel geometry and plaque composition are generally obtained by a semi-automated analysis process that includes time-consuming manual contour editing. A reduction in the number of frames used for volumetric analysis may speed up the analysis, but could increase measurement variability. We repeatedly performed offline volumetric analyses in RF-IVUS image sets of 20 mm-long coronary segments that contained 30 de novo lesions prior to PCI. A 50% reduction in frames decreased the analysis time significantly (from 57.5 ± 7.3 to 35.7 ± 3.7 min; P < 0.0001) while geometric and compositional RF-IVUS measurements did not differ significantly from measurements obtained from all frames. The variability between measurements on the reduced number of frames versus all frames was comparable to the intra-observer measurement variability. In target lesions prior to PCI, offline volumetric RF-IVUS analyses can be performed using a reduced number of image frames (every second frame). This reduces the time of analysis without substantially increasing measurement variability

    Polyclonal and specific antibodies mediate protective immunity against enteric helminth infection

    Get PDF
    Anti-helminth immunity involves CD4+ T cells, yet the precise effector mechanisms responsible for parasite killing or expulsion remain elusive. We now report an essential role for antibodies in mediating immunity against the enteric helminth Heligmosomoides polygyrus (Hp), a natural murine parasite that establishes chronic infection. Polyclonal IgG antibodies, present in naive mice and produced following Hp infection, functioned to limit egg production by adult parasites. Comparatively, affinity-matured parasite-specific IgG and IgA antibodies that developed only after multiple infections were required to prevent adult worm development. These data reveal complementary roles for polyclonal and affinity-matured parasite-specific antibodies in preventing enteric helminth infection by limiting parasite fecundity and providing immune protection against reinfection, respectively. We propose that parasite-induced polyclonal antibodies play a dual role, whereby the parasite is allowed to establish chronicity, while parasite load and spread are limited, likely reflecting the long coevolution of helminth parasites with their hosts

    Mineral Preservatives in the Wood of Stradivari and Guarneri

    Get PDF
    Following the futile efforts of generations to reach the high standard of excellence achieved by the luthiers in Cremona, Italy, by variations of design and plate tuning, current interest is being focused on differences in material properties. The long-standing question whether the wood of Stradivari and Guarneri were treated with wood preservative materials could be answered only by the examination of wood specimens from the precious antique instruments. In a recent communication (Nature, 2006), we reported about the degradation of the wood polymers in instruments of Stradivari and Guarneri, which could be explained only by chemical manipulations, possibly by preservatives. The aim of the current work was to identify the minerals from the small samples of the maple wood which were available to us from the antique instruments. The ashes of wood from one violin and one cello by Stradivari, two violins by Guarneri, one viola by H. Jay, one violin by Gand-Bernardel were analyzed and compared with a variety of commercial tone woods. The methods of analysis were the following: back-scattered electron imaging, X-ray fluorescence maps for individual elements, wave-length dispersive spectroscopy, energy dispersive X-ray spectroscopy and quantitative microprobe analysis. All four Cremonese instruments showed the unmistakable signs of chemical treatments in the form of chemicals which are not present in natural woods, such as BaSO4, CaF2, borate, and ZrSiO4. In addition to these, there were also changes in the common wood minerals. Statistical evaluation of 12 minerals by discriminant analysis revealed: a. a difference among all four Cremona instruments, b. the difference of the Cremonese instruments from the French and English antiques, and c. only the Cremonese instruments differed from all commercial woods. These findings may provide the answer why all attempts to recreate the Stradivarius from natural wood have failed. There are many obvious implications with regard to how the green tone wood should be treated, which chould lead to changes in the practice of violin-making. This research should inspire others to analyze more antique violins for their chemical contents

    Automatic radiographic quantification of hand osteoarthritis; accuracy and sensitivity to change in joint space width in a phantom and cadaver study

    Get PDF
    This is the final version of the article. Available from Springer Verlag via the DOI in this record.OBJECTIVE: To validate a newly developed quantification method that automatically detects and quantifies the joint space width (JSW) in hand radiographs. Repeatability, accuracy and sensitivity to changes in JSW were determined. The influence of joint location and joint shape on the measurements was tested. METHODS: A mechanical micrometer set-up was developed to define and adjust the true JSW in an acrylic phantom joint and in human cadaver-derived phalangeal joints. Radiographic measurements of the JSW were compared to the true JSW. Repeatability, systematic error (accuracy) and sensitivity (defined as the smallest detectable difference (SDD)) were determined. The influence of joint position on the JSW measurement was assessed by varying the location of the acrylic phantom on the X-ray detector with respect to the X-ray beam and the influence of joint shape was determined by using morphologically different human cadaver joints. RESULTS: The mean systematic error was 0.052 mm in the phantom joint and 0.210 mm in the cadaver experiment. In the phantom experiments, the repeatability was high (SDD = 0.028 mm), but differed slightly between joint locations (p = 0.046), and a change in JSW of 0.037 mm could be detected. Dependent of the joint shape in the cadaver hand, a change in JSW between 0.018 and 0.047 mm could be detected. CONCLUSIONS: The automatic quantification method is sensitive to small changes in JSW. Considering the published data of JSW decline in the normal and osteoarthritic population, the first signs of OA progression with this method can be detected within 1 or 2 years.This work was funded by the Dutch Arthritis Association (Reumafonds). The study sponsor had no involvement in study design, data collection, data analysis, or interpretation of the results

    Reproducibility of volumetric intravascular ultrasound radiofrequency-based analysis of coronary plaque composition in vivo

    Get PDF
    Intravascular ultrasound radiofrequency (RF-IVUS) data permit the analysis of coronary plaque composition in vivo and is used as an endpoint of ongoing pharmacological intervention trials. We assessed the reproducibility of volumetric RF-IVUS analyses in mild-to-moderately diseased atherosclerotic human coronary arteries in vivo. A total of 9,212 IVUS analyses on cross-sectional IVUS frames was performed to evaluate the reproducibility of volumetric RF-IVUS measurements in 33 coronary segments with a length of 27 ± 7 mm. For vessel, lumen, and plaque + media volume the relative measurement differences (P = NS for all) were (A = intraobserver comparison, same pullback) −0.40 ± 1.0%; −0.48 ± 1.4%; −0.35 ± 1.6%, (B = intraobserver comparison, repeated pullback) −0.42 ± 1.2%; −0.52 ± 1.8%; −0.43 ± 4.5% (C = interobserver comparison, same pullback) 0.71 ± 1.8%; 0.71 ± 2.2%, and 0.89 ± 5.0%, respectively. For fibrous, fibro-lipidic, calcium, and necrotic-core volumes the relative measurement differences (P = NS for all) were (A) 0.45 ± 2.1%; −1.12 ± 4.9%; −0.84 ± 2.1%; −0.22 ± 1.8%, (B) 1.40 ± 4.1%; 1.26 ± 6.7%; 2.66 ± 7.4%; 0.85 ± 4.4%, and (C) −1.60 ± 4.9%; 3.85 ± 8.2%; 1.66 ± 7.5%, and −1.58 ± 4.7%, respectively. Of note, necrotic-core volume showed on average the lowest measurement variability. Thus, in mild-to-moderate atherosclerotic coronary artery disease the reproducibility of volumetric compositional RF-IVUS measurements from the same pullback is relatively high, but lower than the reproducibility of geometrical IVUS measurements. Measurements from repeated pullbacks and by different observers show acceptable reproducibilities; the volumetric measurement of the necrotic-core shows on average the highest reproducibility of the compositional RF-IVUS measurement
    corecore