256 research outputs found

    Comparison of 8 Physical Barriers Used for Protecting Douglas-Fir Seedlings from Deer Browse

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    The success or failure of forest regeneration efforts in western Oregon and Washington often depends on adequate control of animal damage to young seedlings. Cutover and partially stocked forest lands provide excellent habitat for animals that clip or browse young seedlings. Black and Dimock (1969) estimated that animals were responsible for roughly one out of five reforestation failures. The Cooperative Animal Damage study of coniferous plantations in Oregon and Washington (1963-1975) found that animals damaged an average of 30 percent of all unprotected Douglas-fir seedlings each year on the 165 plots studied (Black et al. 1979). Browsing by deer and elk was by far the most common, accounting for more than two-thirds of the total damage. Animal damage costs the timber industry several million dollars each year in Oregon and Washington. Considering that humans have all but eliminated the key predator to adult deer and elk, the wolf, this situation is not likely to improve

    Amazon Forest Ecosystem Responses to Elevated Atmospheric CO2 and Alterations in Nutrient Availability: Filling the Gaps with Model-Experiment Integration

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    The impacts of elevated CO2 (eCO2) and alterations in nutrient availability on the carbon (C) storage capacity and resilience of the Amazon forest remain highly uncertain. Carbon dynamics are controlled by multiple eco-physiological processes responding to environmental change, but we lack solid experimental evidence, hampering theory development and thus representation in ecosystem models. Here, we present two ecosystem-scale manipulation experiments, to be carried out in the Amazon, that examine tropical ecosystem responses to eCO2 and nutrient addition and thus will elucidate the representation of crucial ecological processes by ecosystem models. We highlight current gaps in our understanding of tropical ecosystem responses to projected global changes in light of the eco-physiological assumptions considered by current ecosystem models. We conclude that a more detailed process-based representation of the spatial (e.g. soil type; plant functional type) and temporal (seasonal and inter-annual variation) diversity of tropical forests is needed to enhance model predictions of ecosystem responses to projected global environmental change

    HIV Care Cascade Among Adolescents in a "Test and Treat" Community-Based Intervention: HPTN 071 (PopART) for Youth Study.

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    PURPOSE: The PopART for Youth (P-ART-Y) study was nested within the HPTN 071 (PopART) trial, a three-arm community randomized trial in 21 communities in Zambia and South Africa. The P-ART-Y study evaluated the acceptability and uptake of a combination HIV prevention package among young people. We report on the HIV care cascade for adolescents aged 10-19 years from 14 communities receiving the full HIV prevention package in Zambia and South Africa. METHODS: Adolescents were offered participation in the PopART intervention, which included universal home-based HIV testing, linkage to care, antiretroviral therapy (ART) adherence, and other services. Data were collected from September 2016 to December 2017, covering the third round (R3) of the intervention. RESULTS: We enumerated (listed) 128,241 adolescents (Zambia: 95,295 and South Africa: 32,946). Of the adolescents offered HIV testing, 81.9% accepted in Zambia and 70.3% in South Africa. Knowledge of HIV status was higher among older adolescents and increased from 31.4% before R3 to 88.3% at the end of R3 in Zambia and from 28.3% to 79.5% in South Africa. Overall, there were 1,710 (1.9%) adolescents identified as living with HIV by the end of R3 (515 new diagnoses and 1,195 self-reported). Of the new diagnoses, 335 (65.0%) were girls aged 15-19 years. The median time to initiate ART was 5 months. ART coverage before and after R3 increased from 61.3% to 78.7% in Zambia and from 65.6% to 87.8% in South Africa, with boys having higher uptake than girls in both countries. CONCLUSIONS: The PopART intervention substantially increased coverage toward the first and second UNAIDS 90-90-90 targets in adolescents

    The D9N, N291S and S447X variants in the lipoprotein lipase (LPL) gene are not associated with Type III Hyperlipidemia

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    <p>Abstract</p> <p>Background</p> <p>Type III hyperlipidemia (Type III HLP) is associated with homozygosity for the ε2 allele of the APOE gene. However only about 10% of ε2 homozygotes develop Type III HLP and it is assumed that additional genetic and/or environmental factors are required for its development. Common variants in the LPL gene have been proposed as likely genetic co-factors.</p> <p>Methods</p> <p>The frequency of the LPL SNPs D9N, N291S and S447X in 100 patients with hyperlipidemia and APOE2/2 genotype has been determined and compared to that in healthy blood donors and patients with hyperlipidemia.</p> <p>Results</p> <p>There were no statistically significant difference in the frequencies of the variants between APOE2/2 patients and controls.</p> <p>Conclusion</p> <p>It is unlikely that the D9N, N291S or S447X variants in the LPL gene play an important role in the development of Type III HLP.</p

    Monitoring Keap1-Nrf2 interactions in single live cells

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    AbstractThe transcription factor NF-E2 p45-related factor 2 (Nrf2) and its negative regulator Kelch-like ECH associated protein 1 (Keap1) control the expression of nearly 500 genes with diverse cytoprotective functions. Keap1, a substrate adaptor protein for Cullin3/Rbx1 ubiquitin ligase, normally continuously targets Nrf2 for degradation, but loses this ability in response to electrophiles and oxidants (termed inducers). Consequently, Nrf2 accumulates and activates transcription of its downstream target genes. Many inducers are phytochemicals, and cruciferous vegetables represent one of the richest sources of inducer activity among the most commonly used edible plants. Here we summarize the discovery of the isothiocyanate sulforaphane as a potent inducer which reacts with cysteine sensors of Keap1, leading to activation of Nrf2. We then describe the development of a quantitative Förster resonance energy transfer (FRET)-based methodology combined with multiphoton fluorescence lifetime imaging microscopy (FLIM) to investigate the interactions between Keap1 and Nrf2 in single live cells, and the effect of sulforaphane, and other cysteine-reactive inducers, on the dynamics of the Keap1–Nrf2 protein complex. We present the experimental evidence for the “cyclic sequential attachment and regeneration” or “conformation cycling” model of Keap1-mediated Nrf2 degradation. Finally, we discuss the implications of this mode of regulation of Nrf2 for achieving a fine balance under normal physiological conditions, and the consequences and mechanisms of disrupting this balance for tumor biology

    A comparison of different community models of antiretroviral therapy delivery with the standard of care among stable HIV+ patients: rationale and design of a non-inferiority cluster randomized trial, nested in the HPTN 071 (PopART) study.

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    BACKGROUND: Following the World Health Organization's (WHO) 2015 guidelines recommending initiation of antiretroviral therapy (ART) irrespective of CD4 count for all people living with HIV (PLHIV), many countries in sub-Saharan Africa have adopted this strategy to reach epidemic control. As the number of PLHIV on ART rises, maintenance of viral suppression on ART for over 90% of PLHIV remains a challenge to government health systems in resource-limited high HIV burden settings. Non facility-based antiretroviral therapy (ART) delivery for stable HIV+ patients may increase sustainable ART coverage in resource-limited settings. Within the HPTN 071 (PopART) trial, two models, home-based delivery (HBD) or adherence clubs (AC), were offered to assess whether they achieved similar viral load suppression (VLS) to standard of care (SoC). In this paper, we describe the trial design and discuss the methodological issues and challenges. METHODS: A three-arm cluster randomized non-inferiority trial, nested in two urban HPTN 071 trial communities in Zambia, randomly allocated 104 zones to SoC (35), HBD (35), or AC (34). ART and adherence support were delivered 3-monthly at home (HBD), adherence clubs (AC), or clinic (SoC). Adult HIV+ patients defined as "stable" on ART were eligible for inclusion. The primary endpoint was the proportion of PLHIV with virological suppression (≤ 1000 copies HIV RNA/ml) at 12 months (± 3months) after study entry across all three arms. Viral load measurement was done at the routine government laboratories in accordance with national guidelines, annually. The study was powered to determine if either of the community-based interventions would yield a viral suppression rate drop compared to SoC of no more than 5% in its absolute value. Both community-based interventions were delivered by community HIV providers (CHiPs). An additional qualitative study using observations, interviews with PLHIV, and FGDs with community HIV providers was nested in this study to complement the quantitative data. DISCUSSION: This trial was designed to provide rigorous randomized evidence of safety and efficacy of non-facility-based delivery of ART for stable PLHIV in high-burden resource-limited settings. This trial will inform policy regarding best practices and what is needed to strengthen scale-up of differentiated models of ART delivery in resource-limited settings. TRIAL REGISTRATION: ClinicalTrials.gov NCT03025165 . Registered on 19 January 2017

    First-line HIV treatment outcomes following the introduction of integrase inhibitors in UK guidelines.

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    OBJECTIVE: To investigate the characteristics and outcomes of people who initiated different antiretroviral therapy (ART) regimens during the era of integrase strand transfer inhibitors (INSTIs). DESIGN: UK-based observational cohort study. METHODS: UK Collaborative HIV Cohort study participants were included if they had started ART between 1 January 2012 and 30 June 2017. Virological failure was defined as the first of two consecutive plasma HIV RNA more than 50 copies/ml, at least 6 months after starting ART. Follow-up was censored at ART discontinuation, class switch or death. The risk of virological failure among those on INSTI, protease inhibitor or nonnucleoside reverse transcriptase inhibitor (NNRTI) regimens was compared using Kaplan-Meier and Cox regression methods. RESULTS: Of 12?585 participants, 45.6% started a NNRTI, 29.0% a protease inhibitor and 25.4% an INSTI regimen. Over a median follow-up of 20.3 months (interquartile range 7.9-38.9), 7.5% of participants experienced virological failure. Compared with those starting an NNRTI regimen, people receiving INSTIs or protease inhibitors were more likely to experience virological failure: INSTI group adjusted hazard ratio 1.52, 95% confidence interval 1.19-1.95, P?=?0.0009; protease inhibitor group adjusted hazard ratio 2.70, 95% confidence interval 2.27-3.21, P less than 0.0001, likelihood ratio test P less than 0.0001. CONCLUSION: First-line INSTI regimens were associated with a lower risk of virological failure than protease inhibitor regimens but both groups were more likely to experience virological failure than those initiating treatment with a NNRTI. There is likely to be residual channelling bias resulting from selected use of INSTIs and protease inhibitors in specific clinical contexts, including in those with a perceived risk of poor adherence

    Effect of Universal Testing and Treatment on HIV Incidence - HPTN 071 (PopART).

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    BACKGROUND: A universal testing and treatment strategy is a potential approach to reduce the incidence of human immunodeficiency virus (HIV) infection, yet previous trial results are inconsistent. METHODS: In the HPTN 071 (PopART) community-randomized trial conducted from 2013 through 2018, we randomly assigned 21 communities in Zambia and South Africa (total population, approximately 1 million) to group A (combination prevention intervention with universal antiretroviral therapy [ART]), group B (the prevention intervention with ART provided according to local guidelines [universal since 2016]), or group C (standard care). The prevention intervention included home-based HIV testing delivered by community workers, who also supported linkage to HIV care and ART adherence. The primary outcome, HIV incidence between months 12 and 36, was measured in a population cohort of approximately 2000 randomly sampled adults (18 to 44 years of age) per community. Viral suppression (<400 copies of HIV RNA per milliliter) was assessed in all HIV-positive participants at 24 months. RESULTS: The population cohort included 48,301 participants. Baseline HIV prevalence was 21% or 22% in each group. Between months 12 and 36, a total of 553 new HIV infections were observed during 39,702 person-years (1.4 per 100 person-years; women, 1.7; men, 0.8). The adjusted rate ratio for group A as compared with group C was 0.93 (95% confidence interval [CI], 0.74 to 1.18; P = 0.51) and for group B as compared with group C was 0.70 (95% CI, 0.55 to 0.88; P = 0.006). The percentage of HIV-positive participants with viral suppression at 24 months was 71.9% in group A, 67.5% in group B, and 60.2% in group C. The estimated percentage of HIV-positive adults in the community who were receiving ART at 36 months was 81% in group A and 80% in group B. CONCLUSIONS: A combination prevention intervention with ART provided according to local guidelines resulted in a 30% lower incidence of HIV infection than standard care. The lack of effect with universal ART was unanticipated and not consistent with the data on viral suppression. In this trial setting, universal testing and treatment reduced the population-level incidence of HIV infection. (Funded by the National Institute of Allergy and Infectious Diseases and others; HPTN 071 [PopArt] ClinicalTrials.gov number, NCT01900977.)
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