1,284 research outputs found
Radio Polarisation Study of High Rotation Measure AGNs
As radio polarised emission from astrophysical objects traverse through
foreground magnetised plasma, the physical conditions along the lines of sight
are encrypted in the form of Rotation Measure (RM). We performed broadband
spectro-polarimetric observations of high Rotation Measure (|RM| >~ 300 rad
m-2) sources away from the Galactic plane (|b| > 10 deg) selected from the NVSS
RM catalogue. The main goals are to verify the NVSS RM values, which could be
susceptible to n{\pi}-ambiguity, as well as to identify the origin of the
extreme RM values. We show that 40 % of our sample suffer from n{\pi}-ambiguity
in the NVSS RM catalogue. There are also hints of RM variabilities over ~20
years epoch for most of our sources, as revealed by comparing the RM values of
the two studies in the same frequency ranges after correcting for
n{\pi}-ambiguity. At last, we demonstrate the possibility of applying
QU-fitting to study the ambient media of AGNs.Comment: 6 pages, 2 figures; Accepted by MDPI Galaxies; Conference Proceedings
for the Polarised Emission from Astrophysical Jets meeting on June 12-16
2017, Ierapetra, Greec
Results of ASERTAA, a randomized prospective crossover pharmacogenetic study of immediate-release versus extended-release tacrolimus in African American kidney transplant recipients
BACKGROUND: Differences in tacrolimus dosing across ancestries is partly attributable to polymorphisms in CYP3A5 genes that encode tacrolimus-metabolizing cytochrome P450 3A5 enzymes. The CYP3A5*1 allele, preponderant in African Americans, is associated with rapid metabolism, subtherapeutic concentrations, and higher dose requirements for tacrolimus, all contributing to worse outcomes. Little is known about the relationship between CYP3A5 genotype and the tacrolimus pharmacokinetic area under the curve (AUC) profile in African Americans or whether pharmacogenetic differences exist between conventional twice-daily, rapidly absorbed, immediate-release tacrolimus (IR-Tac) and once-daily extended-release tacrolimus (LifeCycle Pharma Tac [LCPT]) with a delayed absorption profile.
STUDY DESIGN: Randomized prospective crossover study.
SETTING & PARTICIPANTS: 50 African American maintenance kidney recipients on stable IR-Tac dosing.
INTERVENTION: Recipients were randomly assigned to continue IR-Tac on days 1 to 7 and then switch to LCPT on day 8 or receive LCPT on days 1 to 7 and then switch to IR-Tac on day 8. The LCPT dose was 85% of the IR-Tac total daily dose.
OUTCOMES: Tacrolimus 24-hour AUC (AUC
MEASUREMENTS: CYP3A5 genotype, 24-hour tacrolimus pharmacokinetic profiles.
RESULTS: ∼80% of participants carried the CYP3A5*1 allele (CYP3A5 expressers). There were no significant differences in AUC
LIMITATIONS: This was primarily a pharmacogenetic study rather than an efficacy study; the follow-up period was too short to capture clinical outcomes.
CONCLUSIONS: Achieving therapeutic tacrolimus trough concentrations with IR-Tac in most African Americans results in significantly higher peak concentrations, potentially magnifying the risk for toxicity and adverse outcomes. This pharmacogenetic effect is attenuated by delayed tacrolimus absorption with LCPT.
TRIAL REGISTRATION: Registered at ClinicalTrials.gov, with study number NCT01962922
The power and process of shifting gender norms: Insights from a randomized controlled trial in South Africa
This Project SOAR report summarizes findings from a randomized controlled trial of Tsima ra rihanyu (“working together for health”), a three-year community mobilization program for treatment as prevention that aimed to address the social barriers to HIV testing and treatment in Mpumalanga Province, South Africa. In this report, the authors explore the types of gender norms that are salient for women and men, how these relate to HIV testing and treatment, and the pathways through which gender norms operate to affect women’s and men’s HIV service use and experience and perpetration of intimate partner violence
Credible knowledge: A pilot evaluation of a modified GRADE method using parent-implemented interventions for children with autism
Abstract
Background
Decision-making in child and youth mental health (CYMH) care requires recommendations that are developed through an efficient and effective method and are based on credible knowledge. Credible knowledge is informed by two sources: scientific evidence, and practice-based evidence, that reflects the "real world" experience of service providers. Current approaches to developing these recommendations in relation to CYMH will typically include evidence from one source or the other but do not have an objective method to combine the two. To this end, a modified version of the Grading Recommendations Assessment, Development and Evaluation (GRADE) approach was pilot-tested, a novel method for the CYMH field.
Methods
GRADE has an explicit methodology that relies on input from scientific evidence as well as a panel of experts. The panel established the quality of evidence and derived detailed recommendations regarding the organization and delivery of mental health care for children and youth or their caregivers. In this study a modified GRADE method was used to provide precise recommendations based on a specific CYMH question (i.e. What is the current credible knowledge concerning the effects of parent-implemented, early intervention with their autistic children?).
Results
Overall, it appeared that early, parent-implemented interventions for autism result in positive effects that outweigh any undesirable effects. However, as opposed to overall recommendations, the heterogeneity of the evidence required that recommendations be specific to particular interventions, based on the questions of whether the benefits of a particular intervention outweighs its harms.
Conclusions
This pilot project provided evidence that a modified GRADE method may be an effective and practical approach to making recommendations in CYMH, based on credible knowledge. Key strengths of the process included separating the assessments of the quality of the evidence and the strength of recommendations, transparency in decision-making, and the objectivity of the methods. Most importantly, this method combined the evidence and clinical experience in a more timely, explicit and simple process as compared to previous approaches. The strengths, limitations and modifications of the approach as they pertain to CYMH, are discussed
Evaluating Approaches for Constructing Polygenic Risk Scores for Prostate Cancer in Men of African and European Ancestry
Genome-wide polygenic risk scores (GW-PRSs) have been reported to have better predictive ability than PRSs based on genome-wide significance thresholds across numerous traits. We compared the predictive ability of several GW-PRS approaches to a recently developed PRS of 269 established prostate cancer-risk variants from multi-ancestry GWASs and fine-mapping studies (PRS269). GW-PRS models were trained with a large and diverse prostate cancer GWAS of 107,247 cases and 127,006 controls that we previously used to develop the multi-ancestry PRS269. Resulting models were independently tested in 1,586 cases and 1,047 controls of African ancestry from the California Uganda Study and 8,046 cases and 191,825 controls of European ancestry from the UK Biobank and further validated in 13,643 cases and 210,214 controls of European ancestry and 6,353 cases and 53,362 controls of African ancestry from the Million Veteran Program. In the testing data, the best performing GW-PRS approach had AUCs of 0.656 (95% CI = 0.635-0.677) in African and 0.844 (95% CI = 0.840-0.848) in European ancestry men and corresponding prostate cancer ORs of 1.83 (95% CI = 1.67-2.00) and 2.19 (95% CI = 2.14-2.25), respectively, for each SD unit increase in the GW-PRS. Compared to the GW-PRS, in African and European ancestry men, the PRS269 had larger or similar AUCs (AUC = 0.679, 95% CI = 0.659-0.700 and AUC = 0.845, 95% CI = 0.841-0.849, respectively) and comparable prostate cancer ORs (OR = 2.05, 95% CI = 1.87-2.26 and OR = 2.21, 95% CI = 2.16-2.26, respectively). Findings were similar in the validation studies. This investigation suggests that current GW-PRS approaches may not improve the ability to predict prostate cancer risk compared to the PRS269 developed from multi-ancestry GWASs and fine-mapping
Trans-ancestry genome-wide association meta-analysis of prostate cancer identifies new susceptibility loci and informs genetic risk prediction.
Prostate cancer is a highly heritable disease with large disparities in incidence rates across ancestry populations. We conducted a multiancestry meta-analysis of prostate cancer genome-wide association studies (107,247 cases and 127,006 controls) and identified 86 new genetic risk variants independently associated with prostate cancer risk, bringing the total to 269 known risk variants. The top genetic risk score (GRS) decile was associated with odds ratios that ranged from 5.06 (95% confidence interval (CI), 4.84-5.29) for men of European ancestry to 3.74 (95% CI, 3.36-4.17) for men of African ancestry. Men of African ancestry were estimated to have a mean GRS that was 2.18-times higher (95% CI, 2.14-2.22), and men of East Asian ancestry 0.73-times lower (95% CI, 0.71-0.76), than men of European ancestry. These findings support the role of germline variation contributing to population differences in prostate cancer risk, with the GRS offering an approach for personalized risk prediction
Characterizing Prostate Cancer Risk Through Multi-Ancestry Genome-Wide Discovery of 187 Novel Risk Variants
The transferability and clinical value of genetic risk scores (GRSs) across populations remain limited due to an imbalance in genetic studies across ancestrally diverse populations. Here we conducted a multi-ancestry genome-wide association study of 156,319 prostate cancer cases and 788,443 controls of European, African, Asian and Hispanic men, reflecting a 57% increase in the number of non-European cases over previous prostate cancer genome-wide association studies. We identified 187 novel risk variants for prostate cancer, increasing the total number of risk variants to 451. An externally replicated multi-ancestry GRS was associated with risk that ranged from 1.8 (per standard deviation) in African ancestry men to 2.2 in European ancestry men. The GRS was associated with a greater risk of aggressive versus non-aggressive disease in men of African ancestry (P = 0.03). Our study presents novel prostate cancer susceptibility loci and a GRS with effective risk stratification across ancestry groups
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