2,044 research outputs found

    Optical Coherence Tomography Artifacts Are Associated With Adaptive Optics Scanning Light Ophthalmoscopy Success in Achromatopsia

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    Purpose: To determine whether artifacts in optical coherence tomography (OCT) images are associated with the success or failure of adaptive optics scanning light ophthalmoscopy (AOSLO) imaging in subjects with achromatopsia (ACHM). / Methods: Previously acquired OCT and non-confocal, split-detector AOSLO images from one eye of 66 subjects with genetically confirmed achromatopsia (15 CNGA3 and 51 CNGB3) were reviewed along with best-corrected visual acuity (BCVA) and axial length. OCT artifacts in interpolated vertical volumes from CIRRUS macular cubes were divided into four categories: (1) none or minimal, (2) clear and low frequency, (3) low amplitude and high frequency, and (4) high amplitude and high frequency. Each vertical volume was assessed once by two observers. AOSLO success was defined as sufficient image quality in split-detector images at the fovea to assess cone quantity. / Results: There was excellent agreement between the two observers for assessing OCT artifact severity category (weighted kappa = 0.88). Overall, AOSLO success was 47%. For subjects with OCT artifact severity category 1, AOSLO success was 65%; for category 2, 47%; for category 3, 11%; and for category 4, 0%. There was a significant association between OCT artifact severity category and AOSLO success (P = 0.0002). Neither BCVA nor axial length was associated with AOSLO success (P = 0.07 and P = 0.75, respectively). / Conclusions: Artifacts in OCT volumes are associated with AOSLO success in ACHM. Subjects with less severe OCT artifacts are more likely to be good candidates for AOSLO imaging, whereas AOSLO was successful in only 7% of subjects with category 3 or 4 OCT artifacts. These results may be useful in guiding patient selection for AOSLO imaging. / Translational Relevance: Using OCT to prescreen patients could be a valuable tool for clinical trials that utilize AOSLO to reduce costs and decrease patient testing burden

    Assessing the organizational context for EBP implementation: the development and validity testing of the Implementation Climate Scale (ICS)

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    BACKGROUND: Although the importance of the organizational environment for implementing evidence-based practices (EBP) has been widely recognized, there are limited options for measuring implementation climate in public sector health settings. The goal of this research was to develop and test a measure of EBP implementation climate that would both capture a broad range of issues important for effective EBP implementation and be of practical use to researchers and managers seeking to understand and improve the implementation of EBPs. METHODS: Participants were 630 clinicians working in 128 work groups in 32 US-based mental health agencies. Items to measure climate for EBP implementation were developed based on past literature on implementation climate and other strategic climates and in consultation with experts on the implementation of EBPs in mental health settings. The sample was randomly split at the work group level of analysis; half of the sample was used for exploratory factor analysis (EFA), and the other half was used for confirmatory factor analysis (CFA). The entire sample was utilized for additional analyses assessing the reliability, support for level of aggregation, and construct-based evidence of validity. RESULTS: The EFA resulted in a final factor structure of six dimensions for the Implementation Climate Scale (ICS): 1) focus on EBP, 2) educational support for EBP, 3) recognition for EBP, 4) rewards for EBP, 5) selection for EBP, and 6) selection for openness. This structure was supported in the other half of the sample using CFA. Additional analyses supported the reliability and construct-based evidence of validity for the ICS, as well as the aggregation of the measure to the work group level. CONCLUSIONS: The ICS is a very brief (18 item) and pragmatic measure of a strategic climate for EBP implementation. It captures six dimensions of the organizational context that indicate to employees the extent to which their organization prioritizes and values the successful implementation of EBPs. The ICS can be used by researchers to better understand the role of the organizational context on implementation outcomes and by organizations to evaluate their current climate as they consider how to improve the likelihood of implementation success. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s13012-014-0157-1) contains supplementary material, which is available to authorized users

    Interocular Symmetry of Foveal Cone Topography in Congenital Achromatopsia

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    PURPOSE: To determine interocular symmetry of foveal cone topography in achromatopsia (ACHM) using non-confocal split-detection adaptive optics scanning light ophthalmoscopy (AOSLO). METHODS: Split-detector AOSLO images of the foveal cone mosaic were acquired from both eyes of 26 subjects (mean age 24.3 years; range 8 - 44 years, 14 females) with genetically confirmed CNGA3- or CNGB3-associated ACHM. Cones were identified within a manually delineated rod-free zone. Peak cone density (PCD) was determined using an 80 × 80 μm sampling window within the rod-free zone. The mean and standard deviation (SD) of intercell distance (ICD) were calculated to derive the coefficient of variation (CV). Cone density difference maps were generated to compare cone topography between eyes. RESULTS: PCD (mean ± SD) was 17,530 ± 9,614 cones/mm2 and 17,638 ± 9,753 cones/mm2 for right and left eyes, respectively (p = 0.677, Wilcoxon test). The mean (± SD) for ICD was 9.05 ± 2.55 µm and 9.24 ± 2.55 µm for right and left eyes, respectively (p = 0.410, paired t test). The mean (± SD) for CV of ICD was 0.16 ± 0.03 µm and 0.16 ± 0.04 µm for right and left eyes, respectively (p = 0.562, paired t test). Cone density maps demonstrated that cone topography of the ACHM fovea is non-uniform with local variations in cone density between eyes. CONCLUSIONS: These results demonstrate interocular symmetry of the foveal cone mosaic (both density and packing) in ACHM. As cone topography can differ between eyes of a subject, PCD does not completely describe the foveal cone mosaic in ACHM. Nonetheless, these findings are of value in longitudinal monitoring of patients during treatment trials and further suggest that both eyes of a given subject may have similar therapeutic potential and non-study eye can be used as a control

    Accuracy and repeatability of wrist joint angles in boxing using an electromagnetic tracking system

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    © 2019, The Author(s). The hand-wrist region is reported as the most common injury site in boxing. Boxers are at risk due to the amount of wrist motions when impacting training equipment or their opponents, yet we know relatively little about these motions. This paper describes a new method for quantifying wrist motion in boxing using an electromagnetic tracking system. Surrogate testing procedure utilising a polyamide hand and forearm shape, and in vivo testing procedure utilising 29 elite boxers, were used to assess the accuracy and repeatability of the system. 2D kinematic analysis was used to calculate wrist angles using photogrammetry, whilst the data from the electromagnetic tracking system was processed with visual 3D software. The electromagnetic tracking system agreed with the video-based system (paired t tests) in both the surrogate ( 0.9). In the punch testing, for both repeated jab and hook shots, the electromagnetic tracking system showed good reliability (ICCs > 0.8) and substantial reliability (ICCs > 0.6) for flexion–extension and radial-ulnar deviation angles, respectively. The results indicate that wrist kinematics during punching activities can be measured using an electromagnetic tracking system

    Repeatability and Longitudinal Assessment of Foveal Cone Structure in Cngb3-associated Achromatopsia

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    PURPOSE: Congenital achromatopsia is an autosomal recessive disease causing substantial reduction or complete absence of cone function. Although believed to be a relatively stationary disorder, questions remain regarding the stability of cone structure over time. In this study, the authors sought to assess the repeatability of and examine longitudinal changes in measurements of central cone structure in patients with achromatopsia. METHODS: Forty-one subjects with CNGB3-associated achromatopsia were imaged over a period of between 6 and 26 months using optical coherence tomography and adaptive optics scanning light ophthalmoscopy. Outer nuclear layer (ONL) thickness, ellipsoid zone (EZ) disruption, and peak foveal cone density were assessed. RESULTS: ONL thickness increased slightly compared with baseline (0.184 μm/month, P = 0.02). The EZ grade remained unchanged for 34/41 subjects. Peak foveal cone density did not significantly change over time (mean change 1% per 6 months, P = 0.126). CONCLUSION: Foveal cone structure showed little or no change in this group of subjects with CNGB3-associated achromatopsia. Over the time scales investigated (6–26 months), achromatopsia seems to be a structurally stable condition, although longer-term follow-up is needed. These data will be useful in assessing foveal cone structure after therapeutic intervention

    A Genealogical Interpretation of Principal Components Analysis

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    Principal components analysis, PCA, is a statistical method commonly used in population genetics to identify structure in the distribution of genetic variation across geographical location and ethnic background. However, while the method is often used to inform about historical demographic processes, little is known about the relationship between fundamental demographic parameters and the projection of samples onto the primary axes. Here I show that for SNP data the projection of samples onto the principal components can be obtained directly from considering the average coalescent times between pairs of haploid genomes. The result provides a framework for interpreting PCA projections in terms of underlying processes, including migration, geographical isolation, and admixture. I also demonstrate a link between PCA and Wright's fst and show that SNP ascertainment has a largely simple and predictable effect on the projection of samples. Using examples from human genetics, I discuss the application of these results to empirical data and the implications for inference

    Residual Foveal Cone Structure in CNGB3-Associated Achromatopsia

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    PURPOSE: Congenital achromatopsia (ACHM) is an autosomal recessive disorder in which cone function is absent or severely reduced. Gene therapy in animal models of ACHM have shown restoration of cone function, though translation of these results to humans relies, in part, on the presence of viable cone photoreceptors at the time of treatment. Here, we characterized residual cone structure in subjects with CNGB3-associated ACHM. METHODS: High-resolution imaging (optical coherence tomography [OCT] and adaptive optics scanning light ophthalmoscopy [AOSLO]) was performed in 51 subjects with CNGB3-associated ACHM. Peak cone density and inter-cone spacing at the fovea was measured using split-detection AOSLO. Foveal outer nuclear layer thickness was measured in OCT images, and the integrity of the photoreceptor layer was assessed using a previously published OCT grading scheme RESULTS: Analyzable images of the foveal cones were obtained in 26 of 51 subjects, with nystagmus representing the major obstacle to obtaining high-quality images. Peak foveal cone density ranged from 7,273 to 53,554 cones/mm2, significantly lower than normal (range, 84,733–234,391 cones/mm2), with the remnant cones being either contiguously or sparsely arranged. Peak cone density was correlated with OCT integrity grade; however, there was overlap of the density ranges between OCT grades. CONCLUSIONS: The degree of residual foveal cone structure varies greatly among subjects with CNGB3-associated ACHM. Such measurements may be useful in estimating the therapeutic potential of a given retina, providing affected individuals and physicians with valuable information to more accurately assess the risk-benefit ratio as they consider enrolling in experimental gene therapy trials. (www.clinicaltrials.gov, NCT01846052.

    Dio-sensimedia: a novel culture medium for rapid detection of extended spectrum β-lactamases

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    BACKGROUND: Resistance to contemporary broad-spectrum β-lactams, mediated by extended-spectrum β-lactamases (ESBL), is an increasing problem worldwide. Many of the emerging antimicrobial resistance problems of this decade have been characterized by difficulty in the recognition of resistance in the laboratory, particularly by rapid susceptibility test methods. The plasmid-encoded ESBL represent such a resistance phenomenon that is difficult to recognize. We compared Dio-Sensimedia-ES (DSM-ES; Diomed, Istanbul, Turkey) and Mueller-Hinton (MH) agar in the double-disk synergy test (DDST) as a novel rapid system for detecting ESBL directly from bacterial culture. METHODS: Sixty ESBL-producing Klebsiella pneumoniae isolates cultured from blood (30), endotracheal aspirates (20), urine (5) and pus (5), as well as 40 Escherichia coli isolates cultured from endotracheal aspirates (15), urine (10), blood (8) and pus (7) were studied. Isolates positive for ESBL by the combined disk tests were tested with the DDST using MH and DSM-ES agar to detect ESBL-mediated resistance in K. pneumoniae and E. coli. DSM-ES agar was also used to determine the susceptibility of Enterobacteriaceae and staphylococci. RESULTS: Among 60 ESBL-producing K. pneumoniae isolates, 59 (98.3%) were identified as ESBL-positive by the DDST using MH, and 58 (96.6%), using DSM-ES agar. Of 40 ESBL-producing E. coli isolates, 38 (95%) were ESBL-positive by the DDST on MH agar, and 37 (92.5%), on DSM-ES agar. The average incubation period required for ESBL detection by the DDST on DSM-ES agar was 4 hours. CONCLUSIONS: Since the DDST results were available within 4 hours when DSM-ES agar was used, the use of this media may significantly lower the length of hospital stay, the total cost for patient care and even the mortality rate by fascilitating early treatment against ESBL-producing organisms

    Lack of MEF2A Δ7aa mutation in Irish families with early onset ischaemic heart disease, a family based study

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    BACKGROUND: Ischaemic heart disease (IHD) is a complex disease due to the combination of environmental and genetic factors. Mutations in the MEF2A gene have recently been reported in patients with IHD. In particular, a 21 base pair deletion (Δ7aa) in the MEF2A gene was identified in a family with an autosomal dominant pattern of inheritance of IHD. We investigated this region of the MEF2A gene using an Irish family-based study, where affected individuals had early-onset IHD. METHODS: A total of 1494 individuals from 580 families were included (800 discordant sib-pairs and 64 parent-child trios). The Δ7aa region of the MEF2A gene was investigated based on amplicon size. RESULTS: The Δ7aa mutation was not detected in any individual. Variation in the number of CAG (glutamate) and CCG (proline) residues was detected in a nearby region. However, this was not found to be associated with IHD. CONCLUSION: The Δ7aa mutation was not detected in any individual within the study population and is unlikely to play a significant role in the development of IHD in Ireland. Using family-based tests of association the number of tri-nucleotide repeats in a nearby region of the MEF2A gene was not associated with IHD in our study group

    Racial/Ethnic Disparities in Exercise and Dietary Behaviors of Middle-Aged and Older Adults

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    BackgroundDifferences in health behaviors may be important contributors to racial/ethnic disparities in the health status of adults. Studies to date have not compared whether there are health behavior differences in exercise and dietary behaviors among middle-age and older adults in the four largest racial/ethnic categories.ObjectiveTo investigate racial/ethnic differences in exercise and dietary behaviors of middle-aged and older adults.DesignWe used data from the 2007 California Health Interview Survey. Multivariable logistic regression was used to examine interactions between age and race/ethnicity in predicting two categories of health behaviors. Analyses were conducted adjusting for sociodemographic characteristics, health insurance status, and healthcare utilization.ParticipantsA population-based sample of 33,189 California adults 45 years old and older: 26,522 non-Hispanic whites, 1,686 African American/blacks, 2,565 Asian/Pacific Islanders (1,741 English-proficient; 824 limited English-proficient), and 2,416 Latinos (1,538 English-proficient; 878 limited English-proficient).Main measuresSelf-report leisure-time physical activity (moderate and vigorous) and daily consumption of fruits and vegetables.Key resultsRacial/ethnic minorities generally engaged in less healthy exercise and dietary behaviors than whites, with differences more pronounced in middle adulthood. The disparities were the greatest among English-proficient minorities. Specifically, among middle-aged respondents, all racial/ethnic minorities engaged in less vigorous physical activity than whites (ORs range = 0.28 to 0.73; 95% CI range = 0.16-1.00). Additionally, middle-aged, English-proficient minorities engaged in less moderate physical activity compared to whites (ORs range =0.57 to 0.67; 95% CI range = 0.45-0.79). Furthermore, middle-aged, English-proficient Latinos had a poorer diet than whites (OR = 0.54; 0.39-0.75). Few significant racial/ethnic differences emerged in the exercise and dietary behaviors of older adults.ConclusionsRacial/ethnic disparities in exercise and dietary behaviors are most notable among middle-aged, acculturated minorities. Results highlight the need to promote positive exercise and dietary behaviors during critical preventive ages, when racial/ethnic disparities are large and the potential to prevent chronic disease is great
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