1,230,303 research outputs found

    Safety of opioid patch initiation in Australian residential aged care

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    Explores opioid use by aged care facility residents before and after initiation of transdermal opioid patches. Abstract Objective: To explore opioid use by aged care facility residents before and after initiation of transdermal opioid patches. Design: A cross-sectional cohort study, analysing pharmacy data on individual patient supply between 1 July 2008 and 30 September 2013. Setting: Sixty residential aged care facilities in New South Wales. Participants: Residents receiving an initial opioid patch during the study period Main outcome measure: The proportion of residents who were opioid-naive in the 4 weeks prior to patch initiation was determined. In addition, the patch strength at initiation and the daily dose of transdermal patches and of additional opioids 1 month after initiation were determined. Results: An opioid patch was initiated in 596 of 5297 residents (11.3%: 2.6% fentanyl, 8.7% buprenorphine) in the 60 residential aged care facilities. The mean age at initiation was 87 years, and 74% of the recipients were women. The proportion of recipients who were opioid-naive before patch initiation was 34% for fentanyl and 49% for buprenorphine. Most were initiated at the lowest available patch strength, and the dose was up-titrated after initiation. Around 15% of fentanyl users and 10% of buprenorphine users needed additional regular opioids after patch initiation. Conclusions: The results suggest some inappropriate initiation of opioid patches in Australian residential aged care facilities. Contrary to best practice, a third of residents initiated on fentanyl patches were opioid-naive in the 4 weeks before initiation. &nbsp

    Two RNA-binding motifs in eIF3 direct HCV IRES-dependent translation.

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    The initiation of protein synthesis plays an essential regulatory role in human biology. At the center of the initiation pathway, the 13-subunit eukaryotic translation initiation factor 3 (eIF3) controls access of other initiation factors and mRNA to the ribosome by unknown mechanisms. Using electron microscopy (EM), bioinformatics and biochemical experiments, we identify two highly conserved RNA-binding motifs in eIF3 that direct translation initiation from the hepatitis C virus internal ribosome entry site (HCV IRES) RNA. Mutations in the RNA-binding motif of subunit eIF3a weaken eIF3 binding to the HCV IRES and the 40S ribosomal subunit, thereby suppressing eIF2-dependent recognition of the start codon. Mutations in the eIF3c RNA-binding motif also reduce 40S ribosomal subunit binding to eIF3, and inhibit eIF5B-dependent steps downstream of start codon recognition. These results provide the first connection between the structure of the central translation initiation factor eIF3 and recognition of the HCV genomic RNA start codon, molecular interactions that likely extend to the human transcriptome

    Effectiveness of CenteringPregnancy on Breast-Feeding Initiation Among African Americans: A Systematic Review and Meta-analysis

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    While breastfeeding initiation rates for African American mothers are low, an innovative model of group prenatal care, CenteringPregnancy, holds promise to increase breastfeeding rates. The aim of this systematic review and meta-analysis was to examine the effects of CenteringPregnancy versus individual prenatal care on breastfeeding initiation among African American mothers. Using a systematic approach and PRISMA guidelines, 4 electronic databases were used to search the literature. English-language studies, comparing CenteringPregnancy and individual prenatal care, including African American participants, and specifying breastfeeding initiation as an outcome were screened for inclusion. Study strength and quality were assessed and 7 studies were systematically reviewed and meta-analyzed. Participation in CenteringPregnancy increased the probability of breastfeeding initiation by 53% (95% confidence interval = 29%-81%) (n = 8047). A subgroup analysis of breastfeeding initiationamong only African American participants was performed on 4 studies where data were available. Participation in CenteringPregnancy increased the probability of breastfeeding initiation by 71% (95% confidence interval = 27%-131%) (n = 1458) for African American participants. CenteringPregnancy is an effective intervention to increase breastfeeding initiation for participants, especially for African Americans. To close the racial gap in breastfeeding initiation, high-quality research providing specific outcomes for African American participants in CenteringPregnancy are needed

    Factors associated with antiretroviral treatment initiation amongst HIV-positive individuals linked to care within a universal test and treat programme: early findings of the ANRS 12249 TasP trial in rural South Africa

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    Prompt uptake of antiretroviral treatment (ART) is essential to ensure the success of universal test and treat (UTT) strategies to prevent HIV transmission in high-prevalence settings. We describe ART initiation rates and associated factors within an ongoing UTT cluster-randomized trial in rural South Africa. HIV-positive individuals were offered immediate ART in the intervention arm vs. national guidelines recommended initiation (CD4≤350 cells/mm3) in the control arm. We used data collected up to July 2015 among the ART-eligible individuals linked to TasP clinics before January 2015. ART initiation rates at one (M1), three (M3) and six months (M6) from baseline visit were described by cluster and CD4 count strata (cells/mm3) and other eligibility criteria: ≤100; 100–200; 200–350; CD4>350 with WHO stage 3/4 or pregnancy; CD4>350 without WHO stage 3/4 or pregnancy. A Cox model accounting for covariate effect changes over time was used to assess factors associated with ART initiation. The 514 participants had a median [interquartile range] follow-up duration of 1.08 [0.69; 2.07] months until ART initiation or last visit. ART initiation rates at M1 varied substantially (36.9% in the group CD4>350 without WHO stage 3/4 or pregnancy, and 55.2–71.8% in the three groups with CD4≤350) but less at M6 (from 85.3% in the first group to 96.1–98.3% in the three other groups). Factors associated with lower ART initiation at M1 were a higher CD4 count and attending clinics with both high patient load and higher cluster HIV prevalence. After M1, having a regular partner was the only factor associated with higher likelihood of ART initiation. These findings suggest good ART uptake within a UTT setting, even among individuals with high CD4 count. However, inadequate staffing and healthcare professional practices could result in prioritizing ART initiation in patients with the lowest CD4 counts

    Initiation of HIV therapy

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    In this paper, we numerically show that the dynamics of the HIV system is sensitive to both the initial condition and the system parameters. These phenomena imply that the system is chaotic and exhibits a bifurcation behavior. To control the system, we propose to initiate an HIV therapy based on both the concentration of the HIV-1 viral load and the ratio of the CD4 lymphocyte population to the CD8 lymphocyte population. If the concentration of the HIV-1 viral load is higher than a threshold, then the first type of therapy will be applied. If the concentration of the HIV-1 viral load is lower than or equal to the threshold and the ratio of the CD4 lymphocyte population to the CD8 lymphocyte population is greater than another threshold, then the second type of therapy will be applied. Otherwise, no therapy will be applied. The advantages of the proposed control strategy are that the therapy can be stopped under certain conditions, while the state variables of the overall system is asymptotically stable with fast convergent rate, the concentration of the controlled HIV-1 viral load is monotonic decreasing, as well as the positivity constraint of the system states and that of the dose concentration is guaranteed to be satisfied. Computer numerical simulation results are presented for an illustration

    Single molecule studies on the dynamics of the transcription initiation complex of yeast mitochondria

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    Department of Biomedical EngineeringThe transcription initiation complex in the yeast mitochondria of Saccharomyces cerevisiae comprises the RNA polymerase, Rpo41, the initiation factor, Mtf1, and the DNA including 6 base pair promoter sequence. The Mtf1 is known to recognize and help to open the promoter region during the initiation stage, but its exact role and mechanism still remains unclear. We designed a multi-color single molecule FRET assay to directly measure the dynamics of the complex during transcription initiation. The labels on the DNA report on its opening-closing dynamics, while the label on Mtf1 report on the recruitment, dynamics, and dissociation of the initiation factor. From these measurements, we can correlate the promoter opening dynamics, factor binding/dissociation, and the transition to the elongation phase. Mtf1 is also associated with controlling the production of abortive RNA transcripts. We observed the scrunching motion during transcription by stepping along the DNA template with various combinations of nucleotide substrates. The FRET distribution shifted toward the high FRET region as we stepped further. From these observations, we propose a mechanistic model of the transcription initiation in the yeast mitochondria.ope

    Ribosome recycling, diffusion, and mRNA loop formation in translational regulation

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    We explore and quantify the physical and biochemical mechanisms that may be relevant in the regulation of translation. After elongation and detachment from the 3' termination site of mRNA, parts of the ribosome machinery can diffuse back to the initiation site, especially if it is held nearby, enhancing overall translation rates. The elongation steps of the mRNA-bound ribosomes are modeled using exact and asymptotic results of the totally asymmetric exclusion process (TASEP).Since the ribosome injection rates of the TASEP depend on the local concentrations at the initiation site, a source of ribosomes emanating from the termination end can feed back to the initiation site, leading to a self-consistent set of equations for the steady-state ribosome throughput. Additional mRNA binding factors can also promote loop formation, or cyclization, bringing the initiation and termination sites into close proximity. The probability distribution of the distance between the initiation and termination sites is described using simple noninteracting polymer models. We find that the initiation, or initial ribosome adsorption binding required for maximal throughput can vary dramatically depending on certain values of the bulk ribosome concentration and diffusion constant. If cooperative interactions among the loop-promoting proteins and the initiation/termination sites are considered, the throughput can be further regulated in a nonmonotonic manner. Potential experiments to test the hypothesized physical mechanisms are discussed.Comment: 21 pp, 11 .eps figs, realigned figures and magin
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