730 research outputs found
Validation of methods for converting the original Disease Activity Score (DAS) to the DAS28
© The Author(s) 2018.The Disease Activity Score (DAS) is integral in tailoring the clinical management of rheumatoid arthritis (RA) patients and is an important measure in clinical research. Different versions have been developed over the years to improve reliability and ease of use. Combining the original DAS and the newer DAS28 data in both contemporary and historical studies is important for both primary and secondary data analyses. As such, a methodologically robust means of converting the old DAS to the new DAS28 measure would be invaluable. Using data from The Early RA Study (ERAS), a sub-sample of patients with both DAS and DAS28 data were used to develop new regression imputation formulas using the total DAS score (univariate), and using the separate components of the DAS score (multivariate). DAS were transformed to DAS28 using an existing formula quoted in the literature, and the newly developed formulas. Bland and Altman plots were used to compare the transformed DAS with the recorded DAS28 to ascertain levels of agreement. The current transformation formula tended to overestimate the true DAS28 score, particularly at the higher end of the scale. A formula which uses all separate components of the DAS was found to estimate the scores with a higher level of precision. A new formula is proposed that can be used by other early RA cohorts to convert the original DAS to DAS28.Peer reviewedFinal Published versio
The human DNA glycosylases NEIL1 and NEIL3 excise psoralen-induced DNA-DNA cross-links in a four-stranded DNA structure
Interstrand cross-links (ICLs) are highly cytotoxic DNA lesions that block DNA replication and transcription by preventing strand separation. Previously, we demonstrated that the bacterial and
human DNA glycosylases Nei and NEIL1 excise unhooked psoralen-derived ICLs in three-stranded DNA via hydrolysis of the glycosidic bond between the crosslinked base and deoxyribose sugar. Furthermore, NEIL3 from Xenopus laevis has been shown to cleave psoralen- and abasic site-induced ICLs in Xenopus
egg extracts. Here we report that human NEIL3 cleaves psoralen-induced DNA-DNA cross-links in three-stranded and four-stranded DNA substrates to generate unhooked DNA fragments containing
either an abasic site or a psoralen-thymine monoadduct. Furthermore, while Nei and NEIL1 also cleave a psoralen-induced four-stranded DNA substrate to generate two unhooked DNA duplexes with a nick, NEIL3 targets both DNA strands in the ICL without generating single-strand breaks. The DNA substrate specificities of these Nei-like enzymes imply the occurrence of long uninterrupted three- and four-stranded crosslinked DNA-DNA structures that may originate in vivo from DNA replication fork
bypass of an ICL. In conclusion, the Nei-like DNA glycosylases unhook psoralen-derived ICLs in various DNA structures via a genuine repair mechanism in which complex DNA lesions can be removed without generation of highly toxic double-strand breaks
Magnetic resonance imaging in the diagnosis of white matter signal abnormalities.
Background White matter abnormalities (WMAs) pose a diagnostic challenge when trying to establish etiologic diagnoses. During childhood and adult years, genetic disorders, metabolic disorders and acquired conditions are included in differential diagnoses. To assist clinicians and radiologists, a structured algorithm using cranial magnetic resonance imaging (MRI) has been recommended to aid in establishing working diagnoses that facilitate appropriate biochemical and genetic investigations. This retrospective pilot study investigated the validity and diagnostic utility of this algorithm when applied to white matter signal abnormalities (WMSAs) reported on imaging studies of patients seen in our clinics. Methods The MRI algorithm was applied to 31 patients selected from patients attending the neurometabolic/neurogenetic/metabolic/neurology clinics at a tertiary care hospital. These patients varied in age from 5 months to 79 years old, and were reported to have WMSAs on cranial MRI scans. Twenty-one patients had confirmed WMA diagnoses and 10 patients had non-specific WMA diagnoses (etiology unknown). Two radiologists, blinded to confirmed diagnoses, used clinical abstracts and the WMSAs present on patient MRI scans to classify possible WMA diagnoses utilizing the algorithm. Results The MRI algorithm displayed a sensitivity of 100%, a specificity of 30.0% and a positive predicted value of 74.1%. Cohen\u27s kappa statistic for inter-radiologist agreement was 0.733, suggesting good agreement between radiologists. Conclusions Although a high diagnostic utility was not observed, results suggest that this MRI algorithm has promise as a clinical tool for clinicians and radiologists. We discuss the benefits and limitations of this approach
Mechanism of cell death resulting from DNA interstrand cross-linking in mammalian cells
DNA interstrand cross-links (ICLs) are critical cytotoxic lesions produced by cancer chemotherapeutic agents such as the nitrogen mustards and platinum drugs; however, the exact mechanism of ICL-induced cell death is unclear. Here, we show a novel mechanism of p53-independent apoptotic cell death involving prolonged cell-cycle (G2) arrest, ICL repair involving HR, transient mitosis, incomplete cytokinesis, and gross chromosomal abnormalities resulting from ICLs in mammalian cells. This characteristic ‘giant' cell death, observed by using time-lapse video microscopy, was reduced in ICL repair ERCC1- and XRCC3-deficient cells. Collectively, the results illustrate the coordination of ICL-induced cellular responses, including cell-cycle arrest, DNA damage repair, and cell death
Quality of systematic reviews: an example of studies comparing artificial disc replacement with fusion in the cervical spine.
Cervical artificial disc replacement (C-ADR) is now an alternative to anterior cervical discectomy and fusion (ACDF). Many studies have evaluated the efficacy of C-ADR compared with ACDF. This led to a series of systematic reviews and meta-analyses to evaluate the evidence of the superiority of one intervention against the other. The aim of the study presented here was to evaluate the quality of these reviews and meta-analyses. Medline via Ovid, Embase, and Cochrane Library were searched using the keywords: (total disk replacement, prosthesis, implantation, discectomy, and arthroplasty) AND (cervical vertebrae, cervical spine, and spine) AND (systematic reviews, reviews, and meta-analysis). Screening and data extraction were conducted by two reviewers independently. Two reviewers then assessed the quality of the selected reviews and meta-analysis using 11-item AMSTAR score which is a validated measurement tool to assess the methodological quality of systematic reviews. Screening of full reports of 46 relevant abstracts resulted in the selection of 15 systematic reviews and/or meta-analyses as eligible for this study. The two reviewers' inter-rater agreement level was high as indicated by kappa of >0.72. The AMSTAR score of the reviews ranged from 3 to 11. Only one study (a Cochrane review) scored 100% (AMSTAR 11). Five studies scored below (AMSTAR 5) indicating low-quality reviews. The most significant drawbacks of reviews of a score below 5 were not using an extensive search strategy, failure to use the scientific quality of the included studies appropriately in formulating a conclusion, not assessing publication bias, and not reporting the excluded studies. With a significant exception of a Cochrane review, the methodological quality of systematic reviews evaluating the evidence of C-ADR versus ACDF has to be improved
Identifying models of delivery, care domains and quality indicators relevant to palliative day services: a scoping review protoco
Abstract Background With an ageing population and increasing numbers of people with life-limiting illness, there is a growing demand for palliative day services. There is a need to measure and demonstrate the quality of these services, but there is currently little agreement on which aspects of care should be used to do this. The aim of the scoping review will be to map the extent, range and nature of the evidence around models of delivery, care domains and existing quality indicators used to evaluate palliative day services. Methods Electronic databases (MEDLINE, EMBASE, CINAHL, PsycINFO, Cochrane Central Register of Controlled Trials) will be searched for evidence using consensus development methods; randomised or quasi-randomised controlled trials; mixed methods; and prospective, longitudinal or retrospective case-control studies to develop or test quality indicators for evaluating palliative care within non-residential settings, including day hospices and community or primary care settings. At least two researchers will independently conduct all searches, study selection and data abstraction procedures. Meta-analyses and statistical methods of synthesis are not planned as part of the review. Results will be reported using numerical counts, including number of indicators in each care domain and by using qualitative approach to describe important indicator characteristics. A conceptual model will also be developed to summarise the impact of different aspects of quality in a palliative day service context. Methodological quality relating to indicator development will be assessed using the Appraisal of Indicators through Research and Evaluation (AIRE) tool. Overall strength of evidence will be assessed using the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) system. Final decisions on quality assessment will be made via consensus between review authors. Discussion Identifying, developing and implementing evidence-based quality indicators is critical to the evaluation and continued improvement of palliative care. Review findings will be used to support clinicians and policymakers make decisions on which quality indicators are most appropriate for evaluating day services at the patient and service level, and to identify areas for further research
Linking evapotranspiration seasonal cycles to the water balance of headwater catchments with contrasting land uses
Land use affects evapotranspiration rates and is a primary driver of the catchment water balance. The water balance of two catchments in southeastern Australia dominated by either grazed pasture or blue gum (Eucalyptus globulus) plantation was studied, focusing on the patterns of evapotranspiration (ET) throughout the year. Rainfall, streamflow, and groundwater levels measured between 2015 and 2019 were combined to estimate annual ET using a water balance equation. In the pasture, eddy covariance was used to measure ET from the catchment. Sap flow measurements were used to estimate tree transpiration in May 2017–May 2018 and Feb 2019–Feb 2021 in two different plots within the plantation. The tree transpiration rates were added to interception, estimated as a percentage of annual rainfall, to calculate ET from the plantation catchment. ET in the pasture showed strong seasonal cycles with very low ET rates in summer and ET rates in spring that were larger than the transpiration rates in the plantation, where trees transpired consistently throughout the year. The estimated annual ET from the water balance equation was comparable to ET estimated from other measurements. In the pasture, ET on average accounted for 88% of annual rainfall, while ET in the plantation was on average 93% of rainfall, exceeding it in the years with annual rainfall lower than about 500 mm. The difference between the ET rates in the plantation and the pasture was approximately 30–50 mm y−1. The larger ET rates in the plantation were reflected in a gradual decrease in the groundwater storage. The larger ET rates were enough to cause a decrease in groundwater storage in the plantation but not in the pasture, where groundwater levels remained stable
A Systematic Approach to Multiple Breath Nitrogen Washout Test Quality
Background: Accurate estimates of multiple breath washout (MBW) outcomes require correct operation of the device, appropriate distraction of the subject to ensure they breathe in a manner representative of their relaxed tidal breathing pattern, and appropriate interpretation of the acquired data. Based on available recommendations for an acceptable MBW test, we aimed to develop a protocol to systematically evaluate MBW measurements based on these criteria. Methods: 50MBWtest occasions were systematically reviewed for technical elements and whether the breathing pattern was representative of relaxed tidal breathing by an experienced MBW operator. The impact of qualitative and quantitative criteria on inter-observer agreement was assessed across eight MBW operators (n = 20 test occasions, compared using a Kappa statistic). Results: Using qualitative criteria, 46/168 trials were rejected: 16.6%were technically unacceptable and 10.7% were excluded due to inappropriate breathing pattern. Reviewer agreement was good using qualitative criteria and further improved with quantitative criteria from (κ = 0.53– 0.83%) to (κ 0.73–0.97%), but at the cost of exclusion of further test occasions in this retrospective data analysis. Conclusions: The application of the systematic review improved inter-observer agreement but did not affect reported MBW outcomes
Prevalence of adult ADHD in an all-female prison unit.
There is increasing evidence suggesting a link between ADHD and criminality, including a strong association between ADHD symptoms and the likelihood of being on probation or in prison. Most studies investigating the prevalence of ADHD in prison populations have focused on adult male offenders. In the current study, 69 female prisoners were screened for both childhood and adult ADHD symptoms using the Barkley Adult ADHD Rating Scale-IV. The results indicate that 41 % of the prisoners met the diagnostic criteria for ADHD in childhood and continued to meet criteria for ADHD as adults. More importantly, young female prisoners (aged 18-25) were significantly more likely to report symptoms of ADHD than older prisoners. Prisoners who reported symptoms of ADHD also reported high levels of impairment associated with these symptoms. A better understanding of the prevalence of ADHD in female prison units can highlight specific areas for intervention during rehabilitation, as well as the management of serious incidents within prison
Mobile tablet-based therapies following stroke: a systematic scoping review protocol of attempted interventions and the challenges encountered
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