164 research outputs found

    Consolidated standards of reporting trials (CONSORT) and the completeness of reporting of randomised controlled trials (RCTs) published inmedical journals (Review)

    Get PDF
    Background: An overwhelming body of evidence stating that the completeness of reporting of randomised controlled trials (RCTs) is not optimal has accrued over time. In the mid-1990s, in response to these concerns, an international group of clinical trialists, statisticians, epidemiologists, and biomedical journal editors developed the CONsolidated Standards Of Reporting Trials (CONSORT) Statement. The CONSORT Statement, most recently updated in March 2010, is an evidence-based minimum set of recommendations including a checklist and flow diagram for reporting RCTs and is intended to facilitate the complete and transparent reporting of trials and aid their critical appraisal and interpretation. In 2006, a systematic review of eight studies evaluating the “effectiveness of CONSORT in improving reporting quality in journals” was published. Objectives: To update the earlier systematic review assessing whether journal endorsement of the 1996 and 2001 CONSORT checklists influences the completeness of reporting of RCTs published in medical journals. Search methods: We conducted electronic searches, known item searching, and reference list scans to identify reports of evaluations assessing the completeness of reporting of RCTs. The electronic search strategy was developed inMEDLINE and tailored to EMBASE.We searched the Cochrane Methodology Register and the Cochrane Database of Systematic Reviews using the Wiley interface. We searched the Science Citation Index, Social Science Citation Index, and Arts and Humanities Citation Index through the ISI Web of Knowledge interface. We conducted all searches to identify reports published between January 2005 and March 2010, inclusive. Selection criteria: In addition to studies identified in the original systematic review on this topic, comparative studies evaluating the completeness of reporting of RCTs in any of the following comparison groups were eligible for inclusion in this review: 1) Completeness of reporting of RCTs published in journals that have and have not endorsed the CONSORT Statement; 2) Completeness of reporting of RCTs published in CONSORT-endorsing journals before and after endorsement; or 3) Completeness of reporting of RCTs before and after the publication of the CONSORT Statement (1996 or 2001). We used a broad definition of CONSORT endorsement that includes any of the following: (a) requirement or recommendation in journal’s ’Instructions to Authors’ to follow CONSORT guidelines; (b) journal editorial statement endorsing the CONSORT Statement; or (c) editorial requirement for authors to submit a CONSORT checklist and/or flow diagram with their manuscript. We contacted authors of evaluations reporting data that could be included in any comparison group(s), but not presented as such in the published report and asked them to provide additional data in order to determine eligibility of their evaluation. Evaluations were not excluded due to language of publication or validity assessment. Data collection and analysis: We completed screening and data extraction using standardised electronic forms, where conflicts, reasons for exclusion, and level of agreement were all automatically and centrally managed in web-based management software, DistillerSR¼. One of two authors extracted general characteristics of included evaluations and all data were verified by a second author. Data describing completeness of reporting were extracted by one author using a pre-specified form; a 10%random sample of evaluations was verified by a second author. Any discrepancies were discussed by both authors; we made no modifications to the extracted data. Validity assessments of included evaluations were conducted by one author and independently verified by one of three authors. We resolved all conflicts by consensus. For each comparison we collected data on 27 outcomes: 22 items of the CONSORT 2001 checklist, plus four items relating to the reporting of blinding, and one item of aggregate CONSORT scores. Where reported, we extracted and qualitatively synthesised data on the methodological quality of RCTs, by scale or score. Main results: Fifty-three publications reporting 50 evaluations were included. The total number of RCTs assessed within evaluations was 16,604 (median per evaluation 123 (interquartile range (IQR) 77 to 226) published in a median of six (IQR 3 to 26) journals. Characteristics of the included RCT populations were variable, resulting in heterogeneity between included evaluations. Validity assessments of included studies resulted in largely unclear judgements. The included evaluations are not RCTs and less than 8% (4/53) of the evaluations reported adjusting for potential confounding factors. Twenty-five of 27 outcomes assessing completeness of reporting in RCTs appeared to favour CONSORT-endorsing journals over non-endorsers, of which five were statistically significant. ’Allocation concealment’ resulted in the largest effect, with risk ratio (RR) 1.81 (99% confidence interval (CI) 1.25 to 2.61), suggesting that 81% more RCTs published in CONSORT-endorsing journals adequately describe allocation concealment compared to those published in non-endorsing journals. Allocation concealment was reported adequately in 45% (393/876) of RCTs in CONSORT-endorsing journals and in 22% (329/1520) of RCTs in non-endorsing journals. Other outcomes with results that were significant include: scientific rationale and background in the ’Introduction’ (RR 1.07, 99% CI 1.01 to 1.14); ’sample size’ (RR 1.61, 99% CI 1.13 to 2.29); method used for ’sequence generation’ (RR 1.59, 99% CI 1.38 to 1.84); and an aggregate score over reported CONSORT items, ’total sum score’ (standardised mean difference (SMD) 0.68 (99% CI 0.38 to 0.98)). Authors’ conclusions: Evidence has accumulated to suggest that the reporting of RCTs remains sub-optimal. This review updates a previous systematic review of eight evaluations. The findings of this review are similar to those from the original review and demonstrate that, despite the general inadequacies of reporting of RCTs, journal endorsement of the CONSORT Statement may beneficially influence the completeness of reporting of trials published in medical journals. Future prospective studies are needed to explore the influenc

    Analysis of Qa-1bPeptide Binding Specificity and the Capacity of Cd94/Nkg2a to Discriminate between Qa-1–Peptide Complexes

    Get PDF
    The major histocompatibility complex class Ib protein, Qa-1b, serves as a ligand for murine CD94/NKG2A natural killer (NK) cell inhibitory receptors. The Qa-1b peptide-binding site is predominantly occupied by a single nonameric peptide, Qa-1 determinant modifier (Qdm), derived from the leader sequence of H-2D and L molecules. Five anchor residues were identified in this study by measuring the peptide-binding affinities of substituted Qdm peptides in experiments with purified recombinant Qa-1b. A candidate peptide-binding motif was determined by sequence analysis of peptides eluted from Qa-1 that had been folded in the presence of random peptide libraries or pools of Qdm derivatives randomized at specific anchor positions. The results indicate that Qa-1b can bind a diverse repertoire of peptides but that Qdm has an optimal primary structure for binding Qa-1b. Flow cytometry experiments with Qa-1b tetramers and NK target cell lysis assays demonstrated that CD94/NKG2A discriminates between Qa-1b complexes containing peptides with substitutions at nonanchor positions P4, P5, or P8. Our findings suggest that it may be difficult for viruses to generate decoy peptides that mimic Qdm and raise the possibility that competitive replacement of Qdm with other peptides may provide a novel mechanism for activation of NK cells

    A Single-Blind randomized controlled trial to evaluate the effect of extended counseling on uptake of pre-antiretroviral care in eastern uganda

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>Many newly screened people living with HIV (PLHIV) in Sub-Saharan Africa do not understand the importance of regular pre-antiretroviral (ARV) care because most of them have been counseled by staff who lack basic counseling skills. This results in low uptake of pre-ARV care and late treatment initiation in resource-poor settings. The effect of providing post-test counseling by staff equipped with basic counseling skills, combined with home visits by community support agents on uptake of pre-ARV care for newly diagnosed PLHIV was evaluated through a randomized intervention trial in Uganda.</p> <p>Methods</p> <p>An intervention trial was performed consisting of post-test counseling by trained counselors, combined with monthly home visits by community support agents for continued counseling to newly screened PLHIV in Iganga district, Uganda between July 2009 and June 2010, Participants (N = 400) from three public recruitment centres were randomized to receive either the intervention, or the standard care (the existing post-test counseling by ARV clinic staff who lack basic training in counseling skills), the control arm. The outcome measure was the proportion of newly screened and counseled PLHIV in either arm who had been to their nearest health center for clinical check-up in the subsequent three months +2 months. Treatment was randomly assigned using computer-generated random numbers. The statistical significance of differences between the two study arms was assessed using chi-square and t-tests for categorical and quantitative data respectively. Risk ratios and 95% confidence intervals were used to assess the effect of the intervention.</p> <p>Results</p> <p>Participants in the intervention arm were 80% more likely to accept (take up) pre-ARV care compared to those in the control arm (RR 1.8, 95% CI 1.4-2.1). No adverse events were reported.</p> <p>Conclusions</p> <p>Provision of post-test counseling by staff trained in basic counseling skills, combined with home visits by community support agents had a significant effect on uptake of pre-ARV care and appears to be a cost-effective way to increase the prerequisites for timely ARV initiation.</p> <p>Trial registration</p> <p>The trial was registered by Current Controlled Trials Ltd C/OBioMed Central Ltd as <a href="http://www.controlled-trials.com/ISRCTN94133652">ISRCTN94133652</a> and received financial support from Sida and logistical support from the European Commission.</p

    High aboveground carbon stock of African tropical montane forests

    Get PDF
    Tropical forests store 40-50 per cent of terrestrial vegetation carbon(1). However, spatial variations in aboveground live tree biomass carbon (AGC) stocks remain poorly understood, in particular in tropical montane forests(2). Owing to climatic and soil changes with increasing elevation(3), AGC stocks are lower in tropical montane forests compared with lowland forests(2). Here we assemble and analyse a dataset of structurally intact old-growth forests (AfriMont) spanning 44 montane sites in 12 African countries. We find that montane sites in the AfriMont plot network have a mean AGC stock of 149.4 megagrams of carbon per hectare (95% confidence interval 137.1-164.2), which is comparable to lowland forests in the African Tropical Rainforest Observation Network(4) and about 70 per cent and 32 per cent higher than averages from plot networks in montane(2,5,6) and lowland(7) forests in the Neotropics, respectively. Notably, our results are two-thirds higher than the Intergovernmental Panel on Climate Change default values for these forests in Africa(8). We find that the low stem density and high abundance of large trees of African lowland forests(4) is mirrored in the montane forests sampled. This carbon store is endangered: we estimate that 0.8 million hectares of old-growth African montane forest have been lost since 2000. We provide country-specific montane forest AGC stock estimates modelled from our plot network to help to guide forest conservation and reforestation interventions. Our findings highlight the need for conserving these biodiverse(9,10) and carbon-rich ecosystems. The aboveground carbon stock of a montane African forest network is comparable to that of a lowland African forest network and two-thirds higher than default values for these montane forests.Peer reviewe

    Maintaining Integrity Under Stress:Envelope Stress Response Regulation of Pathogenesis in Gram-Negative Bacteria

    Get PDF
    The Gram-negative bacterial envelope is an essential interface between the intracellular and harsh extracellular environment. Envelope stress responses (ESRs) are crucial to the maintenance of this barrier and function to detect and respond to perturbations in the envelope, caused by environmental stresses. Pathogenic bacteria are exposed to an array of challenging and stressful conditions during their lifecycle and, in particular, during infection of a host. As such, maintenance of envelope homeostasis is essential to their ability to successfully cause infection. This review will discuss our current understanding of the σE- and Cpx-regulated ESRs, with a specific focus on their role in the virulence of a number of model pathogens
    • 

    corecore