3,130 research outputs found
Validating archetypes for the Multiple Sclerosis Functional Composite
Background Numerous information models for electronic health records, such as
openEHR archetypes are available. The quality of such clinical models is
important to guarantee standardised semantics and to facilitate their
interoperability. However, validation aspects are not regarded sufficiently
yet. The objective of this report is to investigate the feasibility of
archetype development and its community-based validation process, presuming
that this review process is a practical way to ensure high-quality information
models amending the formal reference model definitions. Methods A standard
archetype development approach was applied on a case set of three clinical
tests for multiple sclerosis assessment: After an analysis of the tests, the
obtained data elements were organised and structured. The appropriate
archetype class was selected and the data elements were implemented in an
iterative refinement process. Clinical and information modelling experts
validated the models in a structured review process. Results Four new
archetypes were developed and publicly deployed in the openEHR Clinical
Knowledge Manager, an online platform provided by the openEHR Foundation.
Afterwards, these four archetypes were validated by domain experts in a team
review. The review was a formalised process, organised in the Clinical
Knowledge Manager. Both, development and review process turned out to be time-
consuming tasks, mostly due to difficult selection processes between
alternative modelling approaches. The archetype review was a straightforward
team process with the goal to validate archetypes pragmatically. Conclusions
The quality of medical information models is crucial to guarantee standardised
semantic representation in order to improve interoperability. The validation
process is a practical way to better harmonise models that diverge due to
necessary flexibility left open by the underlying formal reference model
definitions. This case study provides evidence that both community- and tool-
enabled review processes, structured in the Clinical Knowledge Manager, ensure
archetype quality. It offers a pragmatic but feasible way to reduce variation
in the representation of clinical information models towards a more unified
and interoperable model
Validating archetypes for the Multiple Sclerosis Functional Composite
Background Numerous information models for electronic health records, such as
openEHR archetypes are available. The quality of such clinical models is
important to guarantee standardised semantics and to facilitate their
interoperability. However, validation aspects are not regarded sufficiently
yet. The objective of this report is to investigate the feasibility of
archetype development and its community-based validation process, presuming
that this review process is a practical way to ensure high-quality information
models amending the formal reference model definitions. Methods A standard
archetype development approach was applied on a case set of three clinical
tests for multiple sclerosis assessment: After an analysis of the tests, the
obtained data elements were organised and structured. The appropriate
archetype class was selected and the data elements were implemented in an
iterative refinement process. Clinical and information modelling experts
validated the models in a structured review process. Results Four new
archetypes were developed and publicly deployed in the openEHR Clinical
Knowledge Manager, an online platform provided by the openEHR Foundation.
Afterwards, these four archetypes were validated by domain experts in a team
review. The review was a formalised process, organised in the Clinical
Knowledge Manager. Both, development and review process turned out to be time-
consuming tasks, mostly due to difficult selection processes between
alternative modelling approaches. The archetype review was a straightforward
team process with the goal to validate archetypes pragmatically. Conclusions
The quality of medical information models is crucial to guarantee standardised
semantic representation in order to improve interoperability. The validation
process is a practical way to better harmonise models that diverge due to
necessary flexibility left open by the underlying formal reference model
definitions. This case study provides evidence that both community- and tool-
enabled review processes, structured in the Clinical Knowledge Manager, ensure
archetype quality. It offers a pragmatic but feasible way to reduce variation
in the representation of clinical information models towards a more unified
and interoperable model
Vitamin D and Disease Severity in Multiple Sclerosis-Baseline Data From the Randomized Controlled Trial (EVIDIMS)
Objective: To investigate the associations between hypovitaminosis D and disease activity in a cohort of relapsing remitting multiple sclerosis (RRMS) and clinically isolated syndrome (CIS) patients.
Methods: In 51 RRMS and 2 CIS patients on stable interferon-β-1b (IFN-β-1b) treatment recruited to the EVIDIMS study (Efficacy of Vitamin D Supplementation in Multiple Sclerosis (NCT01440062) baseline serum vitamin D levels were evaluated. Patients were dichotomized based on the definition of vitamin D deficiency which is reflected by a < 30 vs. ≥ 30 ng/ml level of 25-hydroxyvitamin D (25(OH)D). Possible associations between vitamin D deficiency and both clinical and MRI features of the disease were analyzed.
Results: Median (25, 75% quartiles, Q) 25(OH)D level was 18 ng/ml (12, 24). Forty eight out of 53 (91%) patients had 25(OH)D levels < 30 ng/ml (p < 0.001). Patients with 25(OH)D ≥ 30 ng/ml had lower median (25, 75% Q) T2-weighted lesion counts [25 (24, 33)] compared to patients with 25(OH)D < 30 ng/ml [60 (36, 84), p = 0.03; adjusted for age, gender and disease duration: p < 0.001]. Expanded disability status scale (EDSS) score was negatively associated with serum 25(OH)D levels in a multiple linear regression, including age, sex, and disease duration (adjusted: p < 0.001).
Interpretation: Most patients recruited in the EVIDIMS study were vitamin D deficient. Higher 25(OH)D levels were associated with reduced T2 weighted lesion count and lower EDSS scores
Normative Data and Minimally Detectable Change for Inner Retinal Layer Thicknesses Using a Semi-automated OCT Image Segmentation Pipeline
Neurodegenerative and neuroinflammatory diseases regularly cause optic nerve and
retinal damage. Evaluating retinal changes using optical coherence tomography (OCT)
in diseases like multiple sclerosis has thus become increasingly relevant. However,
intraretinal segmentation, a necessary step for interpreting retinal changes in the context
of these diseases, is not standardized and often requires manual correction. Here
we present a semi-automatic intraretinal layer segmentation pipeline and establish
normative values for retinal layer thicknesses at the macula, including dependencies on
age, sex, and refractive error. Spectral domain OCT macular 3D volume scans were
obtained from healthy participants using a Heidelberg Engineering Spectralis OCT. A
semi-automated segmentation tool (SAMIRIX) based on an interchangeable third-party
segmentation algorithm was developed and employed for segmentation, correction, and
thickness computation of intraretinal layers. Normative data is reported froma 6mmEarly
Treatment Diabetic Retinopathy Study (ETDRS) circle around the fovea. An interactive
toolbox for the normative database allows surveying for additional normative data. We
cross-sectionally evaluated data from218 healthy volunteers (144 females/74males, age
36.5 ± 12.3 years, range 18–69 years). Average macular thickness (MT) was 313.70 ±
12.02 μm, macular retinal nerve fiber layer thickness (mRNFL) 39.53 ± 3.57 μm, ganglion
cell and inner plexiform layer thickness (GCIPL) 70.81 ± 4.87 μm, and inner nuclear layer
thickness (INL) 35.93 ± 2.34 μm. All retinal layer thicknesses decreased with age. MT
and GCIPL were associated with sex, with males showing higher thicknesses. Layer
thicknesses were also positively associated with each other. Repeated-measurement
reliability for the manual correction of automatic intraretinal segmentation results was excellent, with an intra-class correlation coefficient >0.99 for all layers. The SAMIRIX
toolbox can simplify intraretinal segmentation in research applications, and the normative
data application may serve as an expandable reference for studies, in which normative
data cannot be otherwise obtained
Supersolar metal abundances and the Broad Line Region of Narrow-line Seyfert 1 galaxies
Narrow-line Seyfert 1 galaxies (NLSy1) are intriguing due to their extreme
continuum and emission line properties which are not yet well understood. This
paper is motivated by the recent suggestion that NLSy1 galaxies might be young
active galactic nuclei (AGNs) and that they may have supersolar metal
abundances. We have examined the stability of broad emission line region (BLR)
clouds under isobaric perturbation and its dependence on gas metal abundances.
We show that supersolar metallicity increases the range where multiple phases
in pressure balance may exist. This is particularly important for NLSy1s with
steep X-ray spectra where it delays the trend of hindrance of a multi-phase
equilibrium. Finally, the role of warm absorbers in the context of this
scenario is assessed.Comment: A&A, in press (6 pages, 3 figures); preprint and related papers also
available at http://www.xray.mpe.mpg.de/~skomossa
Instrumental Assessment of Stepping in Place Captures Clinically Relevant Motor Symptoms of Parkinson’s Disease
Fluctuations of motor symptoms make clinical assessment in Parkinson's disease a complex task. New technologies aim to quantify motor symptoms, and their remote application holds potential for a closer monitoring of treatment effects. The focus of this study was to explore the potential of a stepping in place task using RGB-Depth (RGBD) camera technology to assess motor symptoms of people with Parkinson's disease. In total, 25 persons performed a 40 s stepping in place task in front of a single RGBD camera (Kinect for Xbox One) in up to two different therapeutic states. Eight kinematic parameters were derived from knee movements to describe features of hypokinesia, asymmetry, and arrhythmicity of stepping. To explore their potential clinical utility, these parameters were analyzed for their Spearman's Rho rank correlation to clinical ratings, and for intraindividual changes between treatment conditions using standard response mean and paired t-test. Test performance not only differed between ON and OFF treatment conditions, but showed moderate correlations to clinical ratings, specifically ratings of postural instability (pull test). Furthermore, the test elicited freezing in some subjects. Results suggest that this single standardized motor task is a promising candidate to assess an array of relevant motor symptoms of Parkinson's disease. The simple technical test setup would allow future use by patients themselves
Foveal changes in aquaporin‐4 antibody seropositive neuromyelitis optica spectrum disorder are independent of optic neuritis and not overtly progressive
Background and purpose: Foveal changes were reported in aquaporin-4 antibody (AQP4-Ab) seropositive neuromyelitis optica spectrum disorder (NMOSD) patients; however, it is unclear whether they are independent of optic neuritis (ON), stem from subclinical ON or crossover from ON in fellow eyes. Fovea morphometry and a statistical classification approach were used to investigate if foveal changes in NMOSD are independent of ON and progressive.
Methods: This was a retrospective longitudinal study of 27 AQP4-IgG + NMOSD patients (49 eyes; 15 ON eyes and 34 eyes without a history of ON [NON eyes]), follow-up median (first and third quartile) 2.32 (1.33-3.28), and 38 healthy controls (HCs) (76 eyes), follow-up median (first and third quartile) 1.95 (1.83-2.54). The peripapillary retinal nerve fibre layer thickness and the volume of combined ganglion cell and inner plexiform layer as measures of neuroaxonal damage from ON were determined by optical coherence tomography. Nineteen foveal morphometry parameters were extracted from macular optical coherence tomography volume scans. Data were analysed using orthogonal partial least squares discriminant analysis and linear mixed effects models.
Results: At baseline, foveal shape was significantly altered in ON eyes and NON eyes compared to HCs. Discriminatory analysis showed 81% accuracy distinguishing ON vs. HCs and 68% accuracy in NON vs. HCs. NON eyes were distinguished from HCs by foveal shape parameters indicating widening. Orthogonal partial least squares discriminant analysis discriminated ON vs. NON with 76% accuracy. In a follow-up of 2.4 (20.85) years, no significant time-dependent foveal changes were found.
Conclusion: The parafoveal area is altered in AQP4-Ab seropositive NMOSD patients suggesting independent neuroaxonal damage from subclinical ON. Longer follow-ups are needed to confirm the stability of the parafoveal structure over time
CEDAR, an online resource for the reporting and exploration of complexome profiling data
Complexome profiling is an emerging ‘omics’ approach that systematically interrogates the composition of protein complexes (the complexome) of a sample, by combining biochemical separation of native protein complexes with mass-spectrometry based quantitation proteomics. The resulting fractionation profiles hold comprehensive information on the abundance and composition of the complexome, and have a high potential for reuse by experimental and computational researchers. However, the lack of a central resource that provides access to these data, reported with adequate descriptions and an analysis tool, has limited their reuse. Therefore, we established the ComplexomE profiling DAta Resource (CEDAR, www3.cmbi.umcn.nl/cedar/), an openly accessible database for depositing and exploring mass spectrometry data from complexome profiling studies. Compatibility and reusability of the data is ensured by a standardized data and reporting format containing the “minimum information required for a complexome profiling experiment” (MIACE). The data can be accessed through a user-friendly web interface, as well as programmatically using the REST API portal. Additionally, all complexome profiles available on CEDAR can be inspected directly on the website with the profile viewer tool that allows the detection of correlated profiles and inference of potential complexes. In conclusion, CEDAR is a unique, growing and invaluable resource for the study of protein complex composition and dynamics across biological systems
The HELLAS2XMM survey: VI. X-ray absorption in the 1dfAGN sample through a spectral analysis
The spectroscopic analysis of 117 serendipitous sources in the HELLAS2XMM 1df
(1 degree field) survey is described. Of these, 106 sources, of which 86% have
a spectroscopic redshift, are used to evaluate the fraction of X-ray absorbed
(log NH>22) Active Galactic Nuclei (AGN) in the 2--10 keV flux range 0.8-20E-14
erg/cm2/s. This fraction turns out lower than what is predicted by two well
known Cosmic X-Ray Background synthesis models, and the discrepancy is
significant at the 99.999% level. This result consolidates the findings
recently obtained by other authors. In the flux interval explored, the data are
consistent with an intrinsic distribution of the absorbing columns (flat per
decade above logNH>21) independent of luminosity and redshift, together with an
AGN luminosity function evolving purely in luminosity. It is shown that, on the
other hand, extrapolation to lower fluxes fails to reproduce the results
inferred from the Chandra Deep Field North survey. It is found that about 40%
of the high luminosity sources in our sample have best fit logNH>22, and the
surface density of these X-ray obscured QSOs can then be estimated at about 48
per square degree, at the flux limit of ~1E-14} erg/cm2/s of the HELLAS2XMM 1df
survey. As a side issue, 5 or 6 out of 60 sources, that is about 10%,
identified with broad line AGN, turn out to be affected by logNH>22 absorption.Comment: A&A in pres
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