3,546 research outputs found

    HIV vaccine trial safety and retention among 18-20 year olds in the HVTN 503/Phambili study support the inclusion of adolescents in future trials

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    Worldwide, many adolescents, especially women, acquire HIV before age 18. Yet to date, no HIV vaccine trials have enrolled adolescents. Reasons for excluding adolescents from these trials include regulations protecting vulnerable subjects and concerns regarding informed consent, social harms, adverse events, and loss to follow-up

    Islet isolation assessment in man and large animals

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    Recent progress in islet isolation from the pancreas of large mammals including man, accentuated the need for the development of precise and reproducible techniques to assess islet yield. In this report both quantitative and qualitative criteria for islet isolation assessment were discussed, the main topics being the determination of number, volume, purity, morphologic integrity and in vitro and in vivo function tests of the final islet preparations. It has been recommended that dithizone should be used as a specific stain for immediate detection of islet tissue making it possible to estimate both the total number of islets (dividing them into classes of 50 μ diameter range increments) and the purity of the final preparation. Appropriate morphological assessment should include confirmation of islet identification, assessment of the morphological integrity and of the purity of the islet preparation. The use of fluorometric inclusion and exclusion dyes together have been suggested as a viability assay to simultaneously quantitate the proportion of cells that are intact or damaged. Perifusion of islets with glucose provides a dynamic profile of glucose-mediated insulin release and of the ability of the cells to down regulate insulin secretion after the glycemic challenge is interrupted. Although perifusion data provides a useful guide to islet viability the quantity and kinetics of insulin release do not necessarily predict islet performance after implantation. Therefore, the ultimate test of islet viability is their function after transplantation into a diabetic recipient. For this reason, in vivo models of transplantation of an aliquot of the final islet preparation into diabetic nude (athymic) rodents have been suggested. We hope that these general guidelines will be of assistance to standardize the assessment of islet isolations, making it possible to better interpret and compare procedures from different centers. © 1990 Casa Editrice il Ponte

    The Nature of Surface Oxides on Corrosion-Resistant Nickel Alloy Covered by Alkaline Water

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    A nickel alloy with high chrome and molybdenum content was found to form a highly resistive and passive oxide layer. The donor density and mobility of ions in the oxide layer has been determined as a function of the electrical potential when alkaline water layers are on the alloy surface in order to account for the relative inertness of the nickel alloy in corrosive environments

    Ethnic inequalities and pathways to care in psychosis in England: a systematic review and meta-analysis

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    © The Author(s). 2018Background: As part of a national programme to tackle ethnic inequalities, we conducted a systematic review and meta-analysis of research on ethnic inequalities in pathways to care for adults with psychosis living in England and/or Wales. Methods: Nine databases were searched from inception to 03.07.17 for previous systematic reviews, including forward and backward citation tracking and a PROSPERO search to identify ongoing reviews. We then carried forward relevant primary studies from included reviews (with the latest meta-analyses reporting on research up to 2012), supplemented by a search on 18.10.17 in MEDLINE, Embase, PsycINFO and CINAHL for primary studies between 2012 and 2017 that had not been covered by previous meta-analyses. Results: Forty studies, all conducted in England, were included for our updated meta-analyses on pathways to care. Relative to the White reference group, elevated rates of civil detentions were found for Black Caribbean (OR = 3.43, 95% CI = 2.68 to 4.40, n = 18), Black African (OR = 3.11, 95% CI = 2.40 to 4.02, n = 6), and South Asian patients (OR = 1.50, 95% CI 1.07 to 2.12, n = 10). Analyses of each Mental Health Act section revealed significantly higher rates for Black people under (civil) Section 2 (OR = 1.53, 95% CI = 1.11 to 2.11, n = 3). Rates in repeat admissions were significantly higher than in first admission for South Asian patients (between-group difference p < 0.01). Some ethnic groups had more police contact (Black African OR = 3.60, 95% CI = 2.15 to 6.05, n = 2; Black Caribbean OR = 2.64, 95% CI = 1.88 to 3.72, n = 8) and criminal justice system involvement (Black Caribbean OR = 2.76, 95% CI = 2.02 to 3.78, n = 5; Black African OR = 1.92, 95% CI = 1.32 to 2.78, n = 3). The White Other patients also showed greater police and criminal justice system involvement than White British patients (OR = 1.49, 95% CI = 1.03 to 2.15, n = 4). General practitioner involvement was less likely for Black than the White reference group. No significant variations over time were found across all the main outcomes. Conclusions: Our updated meta-analyses reveal persisting but not significantly worsening patterns of ethnic inequalities in pathways to psychiatric care, particularly affecting Black groups. This provides a comprehensive evidence base from which to inform policy and practice amidst a prospective Mental Health Act reform. Trial registration: CRD42017071663Peer reviewedFinal Published versio

    Chromosome assignment of two cloned DNA probes hybridizing predominantly to human sex chromosomes

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    In situ hybridization experiments were carried out with two clones, YACG 35 and 2.8, which had been selected from two genomic libraries strongly enriched for the human Y chromosome. Besides the human Y chromosome, both sequences strongly hybridized to the human X chromosome, with few minor binding sites on autosomes. In particular, on the X chromosome DNA from clone YACG 35 hybridized to the centromeric region and the distal part of the short arm (Xp2.2). On the Y chromosome, the sequence was assigned to one site situated in the border region between Yq1.1 and Yq1.2. DNA from clone 2.8 also hybridized to the centromeric region of the X and the distal part of the short arm (Xq2.2). On the Y, however, two binding sites were observed (Yp1.1 and Yq1.2). The findings indicate that sex chromosomal sequences may be localized in homologous regions (as suggested from meiotic pairing) but also at ectopic sites

    Antisense DNA parameters derived from next-nearest-neighbor analysis of experimental data

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    <p>Abstract</p> <p>Background</p> <p>The enumeration of tetrameric and other sequence motifs that are positively or negatively correlated with <it>in vivo </it>antisense DNA effects has been a useful addition to the arsenal of information needed to predict effective targets for antisense DNA control of gene expression. Such retrospective information derived from <it>in vivo </it>cellular experiments characterizes aspects of the sequence dependence of antisense inhibition that are not predicted by nearest-neighbor (NN) thermodynamic parameters derived from <it>in vitro </it>experiments. However, quantitation of the antisense contributions of motifs is problematic, since individual motifs are not isolated from the effects of neighboring nucleotides, and motifs may be overlapping. These problems are circumvented by a next-nearest-neighbor (NNN) analysis of antisense DNA effects in which the overlapping nature of nearest-neighbors is taken into account.</p> <p>Results</p> <p>Next-nearest-neighbor triplet combinations of nucleotides are the simplest that include overlapping sequence effects and therefore can encompass interactions beyond those of nearest neighbors. We used singular value decomposition (SVD) to fit experimental data from our laboratory in which phosphorothioate-modified antisense DNAs (S-DNAs) 20 nucleotides long were used to inhibit cellular protein expression in 112 experiments involving four gene targets and two cell lines. Data were fitted using a NNN model, neglecting end effects, to derive NNN inhibition parameters that could be combined to give parameters for a set of 49 sequences that represents the inhibitory effects of all possible overlapping triplet interactions in the cellular targets of these antisense S-DNAs. We also show that parameters to describe subsets of the data, such as the mRNAs being targeted and the cell lines used, can be included in such a derivation. While NNN triplet parameters provided an adequate model to fit our data, NN doublet parameters did not.</p> <p>Conclusions</p> <p>The methodology presented illustrates how NNN antisense inhibitory information can be derived from <it>in vivo </it>cellular experiments. Subsequent calculations of the antisense inhibitory parameters for any mRNA target sequence automatically take into account the effects of all possible overlapping combinations of nearest-neighbors in the sequence. This procedure is more robust than the tallying of tetrameric motifs that have positive or negative antisense effects. The specific parameters derived in this work are limited in their applicability by the relatively small database of experiments that was used in their derivation.</p

    Mutual information rate and bounds for it

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    The amount of information exchanged per unit of time between two nodes in a dynamical network or between two data sets is a powerful concept for analysing complex systems. This quantity, known as the mutual information rate (MIR), is calculated from the mutual information, which is rigorously defined only for random systems. Moreover, the definition of mutual information is based on probabilities of significant events. This work offers a simple alternative way to calculate the MIR in dynamical (deterministic) networks or between two data sets (not fully deterministic), and to calculate its upper and lower bounds without having to calculate probabilities, but rather in terms of well known and well defined quantities in dynamical systems. As possible applications of our bounds, we study the relationship between synchronisation and the exchange of information in a system of two coupled maps and in experimental networks of coupled oscillators

    Ablative therapy for people with localised prostate cancer: a systematic review and economic evaluation

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    © Queen’s Printer and Controller of HMSO 2015.Background People diagnosed with cancer of the prostate, a sex gland in the pelvis, have a choice of treatment options depending on the severity of disease. For people whose cancer is at medium and low risk of spread, the main options are surgical removal of the prostate, radical prostatectomy (RP), use of external beam radiotherapy (EBRT) to destroy the cancer or delaying treatment until there are signs that the cancer is getting worse [active surveillance (AS)]. RP and radiotherapy are effective at curing the cancer but may also cause long-term urinary incontinence and sexual problems. AS, on the other hand, may be quite difficult for people to cope with as they know that the cancer is still present. Newer treatments aim to target the disease more precisely so that surrounding normal tissues can be preserved, reducing the risk of side effects but still effectively destroying the cancer. These more targeted ablative therapies include cryotherapy, high-intensity focused ultrasound (HIFU), brachytherapy, photodynamic therapy (PDT), radiofrequency interstitial tumour ablation (RITA) and laser therapy, among others. Aims This study aimed to develop clinical care pathways relevant to a UK NHS context review systematically the evidence of the clinical effectiveness and safety of each newer ablative therapy concerning primary and salvage treatment of localised prostate cancer• determine which therapies are most likely to be cost-effective for implementation in the UK NHS identify and prioritise future research needs. Methods Clinical effectiveness review We conducted two discrete systematic reviews: (a) primary ablative treatment of localised prostate cancer compared with AS, RP or EBRT (b) salvage ablative treatment for local prostate cancer relapse after primary EBRT compared with salvage RP. MEDLINE, MEDLINE In-Process & Other Non-Indexed Citations, EMBASE, Bioscience Information Service (BIOSIS), Science Citation Index, Cochrane Central Register of Controlled Trials (CENTRAL), Cochrane Database of Systematic Reviews (CDSR), Database of Abstracts of Reviews of Effects (DARE) and the Health Technology Assessment (HTA) databases were searched to the end of March 2013. Reference lists of all included studies were scanned and experts on our advisory panel were contacted for details of additional reports. Evidence came from randomised controlled trials (RCTs), non-randomised comparative studies (NRCSs) (if no RCT evidence was identified) and single-arm cohort studies (case series) with greater than 10 participants for the ablative procedures only. Conference abstracts or non-English-language reports were excluded. For the primary therapy systematic review, the ablative therapies considered were cryotherapy, HIFU, PDT, RITA, laser ablation and brachytherapy. The comparators were AS, RP and EBRT. For the salvage therapy systematic review, the ablative therapies considered were cryotherapy and HIFU. The comparator was RP. Outcomes were cancer related, adverse effects (functional and procedural) and quality of life. Two reviewers extracted data and carried out quality assessment. For meta-analysis, a Bayesian indirect mixed-treatment comparison was used. Cost-effectiveness The cost-effectiveness of the different treatments and their subsequent care pathways was assessed using a modified Markov individual simulation model, applied to a UK NHS setting. The perspective for the model was a health services perspective. Parameter estimates were derived from the systematic review of clinical effectiveness, a micro-costing exercise, other literature, the expert advisory group and other UK sources. The outputs of the model were costs and quality-adjusted life-years (QALYs) for each procedure, incremental costs and QALYs and incremental cost per QALY over the remaining lifetime. Both costs and QALYs were discounted at 3.5%. An elasticity analysis, together with probabilistic and deterministic sensitivity analyses, were performed to explore the uncertainty surrounding parameter estimates. Results Clinical effectiveness Cryotherapy Data from 3995 patients who received cryotherapy across 19 studies (1 RCT, 4 NRCSs and 14 case series) were included, with most studies considered to be at high risk of bias. In the short term, there was conflicting evidence relating to cancer-specific outcomes when cryotherapy was compared with either EBRT or surgery. The only finding that reached statistical significance was 1-year disease-free survival, which was worse for cryotherapy than for either EBRT or RP. However, none of the other cancer-specific outcomes, such as biochemical failure or overall survival, showed any significant differences between them. The findings in relation to cancer-specific outcomes are best regarded as inconclusive. There was evidence that the rate of urinary incontinence at 1 year was lower for people undergoing cryotherapy than for those undergoing RP [3% vs. 66%; odds ratio (OR) 0.02, 95% credible interval (CrI) < 0.01 to 0.34], but the size of the difference decreased with longer follow-up. There was a general trend for cryotherapy to have fewer procedural complications, apart from urinary retention. The only difference that reached statistical significance was for urethral stricture, which was less frequent after cryotherapy than after RP (1% vs. 8%; OR 0.24, 95% CrI 0.09 to 0.54). High-intensity focused ultrasound Data from 4000 patients who received HIFU across 21 studies (1 NRCS and 20 case series) were included, with all studies considered to be at high risk of bias. There was some evidence that biochemical failure rates were higher at 1 year when using HIFU than when using EBRT, and this was statistically significant. However, the difference was no longer statistically significant at 5 years. Similar findings were observed with regard to disease-free survival at 1 year, with worse outcomes for HIFU than for EBRT, which were statistically significant. The differences were no longer significant at 3 years. The biochemical result was in contrast to overall survival at 4 years, which was higher when using HIFU. There were insufficient data on any urinary incontinence, erectile dysfunction or bowel problems to draw any robust conclusions, although at 1 year HIFU had lower incontinence rates than RP (10% vs. 66%; OR 0.06, 95% CrI 0.01 to 0.48). The safety profile for HIFU was generally good, apart from a potential numerical increase in rates of urinary retention and dysuria. However, HIFU appeared to have a slightly higher incidence of urethral stricture than EBRT, and the difference was statistically significant (8% vs. 1%; OR 5.8, 95% CrI 1.2 to 24.5). Brachytherapy This review considered data from 26,129 patients who received brachytherapy across 40 studies (2 RCTs and 38 NRCSs), with most studies considered to be at high risk of bias. The data for brachytherapy were generally more robust than for other ablative therapies. In the short term, there was some evidence at 5-year follow-up that the rate of biochemical failure was lower for brachytherapy (7%) than for EBRT (13%; OR 0.46, 95% CrI 0.32 to 0.67) or RP (11%; OR 0.35, 95% CrI 0.21 to 0.56). There was also some evidence that disease-free survival was better for brachytherapy at 3-year follow-up. There was evidence that the rate of urinary incontinence up to 5 years after treatment was lower for people undergoing brachytherapy than for RP, but the size of the difference decreased with longer follow-up. There was also a trend towards lower erectile dysfunction rates for brachytherapy than for EBRT or RP and this reached statistical significance at 3 years after treatment (60% vs. 81% for EBRT and 88% for RP). There were insufficient data to draw any conclusions on bowel problems. The findings regarding procedural complications were mixed. Dysuria rates were higher for brachytherapy and this reached statistical significance when compared with RP. Urinary retention was also statistically significantly higher for brachytherapy than for EBRT. Stricture rates for brachytherapy were higher than those for EBRT, but lower than those for RP. The differences for stricture reached statistical significance when compared with RP. For rectal pain, there was evidence that rates were significantly lower for brachytherapy than for EBRT. Acute genitourinary toxicity, though rare, had statistically higher rates for brachytherapy than for EBRT, but acute gastrointestinal toxicity was lower for brachytherapy. Other ablative therapies Only two other ablative therapies were identified in the review: focal laser ablative therapy and PDT. Data were too scarce (a total of 35 participants for these two procedures) for any conclusions. Salvage therapy Data from 400 participants who were treated with salvage therapy following primary EBRT across nine case series were included. Six studies involved salvage RP, two involved salvage cryotherapy and one involved salvage HIFU. In six studies, data were not collected prospectively, and only short-term outcomes were reported. As such, all of the studies were considered as having a high risk of bias. There was no robust evidence that mortality or other cancer-specific outcomes differed between salvage cryotherapy and salvage RP in the short term. There were no data on cancer-specific outcomes for salvage HIFU. In regard to functional and quality of life outcomes, lack of data prevented any conclusions. In terms of adverse event outcomes, salvage cryotherapy had numerically fewer periprocedural complications (especially for bladder neck stenosis) than salvage HIFU or salvage RP, but there was a high level of uncertainty with this observation. Focal ablation Descriptive subgroup assessment within studies reporting the use of focal ablation was limited, but suggested that cancer-specific outcomes were at least comparable with those seen in full-gland therapy studies. Urinary incontinence rates may be lower following focal ablation, but the evidence is weak in light of the poor quality and quantity of the data. Active surveillance Lack of outcome data prevented comparison of the efficacy of ablative therapies with a programme of AS, apart from the rate of erectile dysfunction at 12 months, where there was no statistically significant difference. Cost-effectiveness Assuming equal recurrence in line with the lack of statistical differences from the effectiveness review, EBRT was the least costly (£19,363 per patient) and least effective (3.63 QALYs), whereas HIFU was more costly (£19,860 per patient) and more effective (3.86 QALYs). HIFU was more effective and less costly than the other newer ablative interventions. The lifetime incremental cost per QALY for HIFU compared with EBRT was £2915. There was a 75% chance that HIFU would be considered cost-effective at a £30,000-per-QALY threshold. In a plausible best-and-worst-case analysis, the probability that HIFU would be considered cost-effective varied between 60% and 70%. Strengths and limitations The main strength of the study was the systematic approach taken to review the literature and the inclusion of a relatively large quantity of studies, giving a high total number of participants. The main limitations were the low quantity and poor quality of the data available on cancer-related outcomes and long-term adverse events of urinary incontinence, sexual and bowel dysfunction, and the changing technology over the review period. Many published studies were poorly reported or lacked sufficient detail. Inconsistency in outcome definition, measurement and reporting was also a significant problem, and much of the information available was unsuitable for meta-analysis. Another major limitation resulted from the majority of comparisons being made using case series, with few head-to-head comparisons of ablative therapies against current practice. The estimates were therefore generated using indirect comparisons. Like all analyses, they require assumptions to be made that may or may not be reasonable. Accordingly, the results should be interpreted with a large degree of caution. Despite the considerable efforts to construct a model and seek the best data available, the lack of effectiveness data had implications for the economic evaluation. The limited data meant that there was insufficient evidence to assume that there was any difference between interventions for a number of parameters, a particular issue for biochemical recurrence, which was a key parameter in the evaluation. The impact of these assumptions was explored in sensitivity analyses. Conclusions Implications for health care For primary ablative therapy, neither cryotherapy nor HIFU had sufficiently robust data to enable any definitive conclusions to be made. The effectiveness data on brachytherapy were more robust and there was some evidence that cancer-specific outcomes in the short term were either better or equivalent to either EBRT or RP, with comparable adverse effect profiles apart from a possible increased risk of dysuria and urinary retention. The findings on focal ablative therapy were mostly derived from data on focal cryotherapy, which suggested that cancer-specific outcomes were at least comparable with those of full-gland cryotherapy, and there was a suggestion that the urinary incontinence outcome may be better following focal cryotherapy than whole-gland cryotherapy. The cost-effectiveness analysis confirmed the uncertainty from the clinical review and that there is no technology which appears superior, on the basis of current evidence, in terms of average cost-effectiveness. The probabilistic sensitivity analyses suggest that a number of ablative techniques are worthy of further research. For salvage ablative therapy following primary EBRT, a lack of reliable and robust data prevented any meaningful conclusions from being made, in comparison with salvage RP. The findings from the review indicate that there is insufficient evidence to help inform recommendations on the use of ablative therapies in the UK NHS. Need for further research The main gaps in the evidence base are the lack of direct comparative studies of ablative therapies; the consequent lack of robust data to inform calculations of cost-effectiveness and the role of focal ablative therapies; and the lack of longer-term data on cancer control, such as overall and cancer-specific mortality. The key research recommendations, in order of importance, are as follows: 1. HIFU and brachytherapy seem the most promising newer interventions but they lack high-quality evaluation. Such evaluation should ideally be by multicentre RCT with long-term follow-up, and would include predefined assessment of cancer-specific, dysfunction and health-related quality-of-life measures. Such studies should incorporate economic evaluations and also inform economic modelling

    Risk factors for severe outcomes in patients with systemic vasculitis & COVID‐19: a bi‐national registry‐based cohort study

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    OBJECTIVE: COVID-19 is a novel infectious disease with a broad spectrum of clinical severity. Patients with systemic vasculitis have an increased risk of serious infections and so may be at risk of severe outcomes following COVID-19. It is important to establish the risk factors for severe COVID-19 outcomes in these patients, including the impact of immunosuppressive therapies. METHODS: A multi-centre cohort was developed through the participation of centres affiliated with national UK and Ireland vasculitis registries. Clinical characteristics and outcomes were described. Logistic regression was used to evaluate associations between potential risk factors and severe COVID-19 outcome, defined as a requirement for advanced oxygen therapy, invasive ventilation, or death. RESULTS: Sixty-five cases of patients with systemic vasculitis who developed COVID-19 were reported (median age 70 years, 49% female) of whom 25 (38%) experienced a severe outcome. Most cases (55/65, 85%) had ANCA-associated vasculitis (AAV). Almost all patients required hospitalization (59/65, 91%), 7 patients (11%) were admitted to intensive care and 18 patients (28%) died. Background glucocorticoid therapy was associated with severe outcome (adjusted odds ratio [aOR] 3.7 (1.1-14.9, p=0.047)) as was comorbid respiratory disease (aOR 7.5 (1.9-38.2, p=0.006)). Vasculitis disease activity and non-glucocorticoid immunosuppression were not associated with severe outcome. CONCLUSION: In patients with systemic vasculitis, glucocorticoid use at presentation and comorbid respiratory disease were associated with severe outcomes in COVID-19. These data can inform clinical decision making relating to risk of severe COVID-19 in this vulnerable patient group
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