217 research outputs found

    Influence of the Location of the Internal Temperature Control Loop on the Performance of the Dual Temperature Control for Feed Temperature Disturbance

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    A control strategy with distributed corrective action for distillation has been proposed and consists of a conventional dual temperature control combined with an additional column tray. In this work, we evaluated the influence of the location of this internal loop as part of the new proposal, compared to a conventional system. Tests were carried out in a 13-column tray distillation equipment and feed temperature was disturbed. Two different column trays from the stripping section were used (11 and 12) for internal decentralized temperature control, each one separately, plus the dual control of top and bottom temperatures. The results demonstrated that this proposed control approach with distributed corrective action is faster than the conventional one, regardless of the column tray in use. It was also determined that the internal loop close to the feed (disturbance) is more interesting as a way to minimize transients

    DNA resection in eukaryotes: deciding how to fix the break

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    DNA double-strand breaks are repaired by different mechanisms, including homologous recombination and nonhomologous end-joining. DNA-end resection, the first step in recombination, is a key step that contributes to the choice of DSB repair. Resection, an evolutionarily conserved process that generates single-stranded DNA, is linked to checkpoint activation and is critical for survival. Failure to regulate and execute this process results in defective recombination and can contribute to human disease. Here, I review recent findings on the mechanisms of resection in eukaryotes, from yeast to vertebrates, provide insights into the regulatory strategies that control it, and highlight the consequences of both its impairment and its deregulation

    Mycophenolic acid in the treatment of birdshot chorioretinopathy: long-term follow-up

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    Aim: To assess the long-term efficacy and tolerability of both derivatives of mycophenolic acid, mycophenolate mofetil (MMF) and mycophenolate sodium (MPS), in the therapy of patients with birdshot chorioretinopathy (BSCR). Methods: Retrospective analysis of 24 patients (48 eyes) with BSCR, treated with MMF or MPS with a follow-up of at least 1 year. The main outcome measures included control of inflammation, steroid-sparing potential and side effects. Secondary outcome measure was the development of retinal function during the therapy measured by best-corrected visual acuity (BCVA), visual field and/or electroretinography (ERG). Results: Twelve patients (50%) were treated with MMF and 12 patients (50%) with MPS. Control of intraocular inflammation, defined as complete lack of clinical and angiographic signs of inflammatory activity, was achieved in 16 of 24 patients (67%). The angiographic signs of activity were significantly reduced during the follow-up (p0.05). In 20 out of 21 patients (95%) who received systemic corticosteroids, the corticosteroids could be tapered to a daily dose of ≤10 mg (rate 0.26/patient-year). Drug-related side effects occurred in 12 patients (50%, rate 0.16/patient-year). In four patients (17%), a therapy switch from MMF to MPS was undertaken due to gastrointestinal discomfort. Conclusions: Derivatives of mycophenolic acid are effective and safe drugs for the treatment of BSCR. In cases with gastrointestinal side effects, a therapy switch from MMF to MPS should be considered

    DNA Resection at Chromosome Breaks Promotes Genome Stability by Constraining Non-Allelic Homologous Recombination

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    DNA double-strand breaks impact genome stability by triggering many of the large-scale genome rearrangements associated with evolution and cancer. One of the first steps in repairing this damage is 5′→3′ resection beginning at the break site. Recently, tools have become available to study the consequences of not extensively resecting double-strand breaks. Here we examine the role of Sgs1- and Exo1-dependent resection on genome stability using a non-selective assay that we previously developed using diploid yeast. We find that Saccharomyces cerevisiae lacking Sgs1 and Exo1 retains a very efficient repair process that is highly mutagenic to genome structure. Specifically, 51% of cells lacking Sgs1 and Exo1 repair a double-strand break using repetitive sequences 12–48 kb distal from the initial break site, thereby generating a genome rearrangement. These Sgs1- and Exo1-independent rearrangements depend partially upon a Rad51-mediated homologous recombination pathway. Furthermore, without resection a robust cell cycle arrest is not activated, allowing a cell with a single double-strand break to divide before repair, potentially yielding multiple progeny each with a different rearrangement. This profusion of rearranged genomes suggests that cells tolerate any dangers associated with extensive resection to inhibit mutagenic pathways such as break-distal recombination. The activation of break-distal recipient repeats and amplification of broken chromosomes when resection is limited raise the possibility that genome regions that are difficult to resect may be hotspots for rearrangements. These results may also explain why mutations in resection machinery are associated with cancer

    Development of a Core Outcome Set for Clinical Trials in Non-infectious Uveitis of the Posterior Segment

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    Purpose: To develop an agreed upon set of outcomes known as a “core outcome set” (COS) for noninfectious uveitis of the posterior segment (NIU-PS) clinical trials. Design: Mixed-methods study design comprising a systematic review and qualitative study followed by a 2-round Delphi exercise and face-to-face consensus meeting. Participants: Key stakeholders including patients diagnosed with NIU-PS, their caregivers, and healthcare professionals involved in decision-making for patients with NIU-PS, including ophthalmologists, nurse practitioners, and policymakers/commissioners. Methods: A long list of outcomes was developed based on the results of (1) a systematic review of clinical trials of NIU-PS and (2) a qualitative study of key stakeholders including focus groups and interviews. The long list was used to generate a 2-round Delphi exercise of stakeholders rating the importance of outcomes on a 9-point Likert scale. The proportion of respondents rating each item was calculated, leading to recommendations of “include,” “exclude,” or “for discussion” that were taken to a face-to-face consensus meeting of key stakeholders at which they agreed on the final COS. Main Outcome Measure: Items recommended for inclusion in the COS for NIU-PS. Results: A total of 57 outcomes grouped in 11 outcome domains were presented for evaluation in the Delphi exercise, resulting in 9 outcomes directly qualifying for inclusion and 15 outcomes being carried forward to the consensus meeting, of which 7 of 15 were agreed on for inclusion. The final COS contained 16 outcomes organized into 4 outcome domains comprising visual function, health-related quality of life, treatment side effects, and disease control. Conclusions: This study builds on international work across the clinical trials community and our qualitative research to construct the world's first COS for NIU-PS. The COS provides a list of outcomes that represent the priorities of key stakeholders and provides a minimum set of outcomes for use in all future NIU-PS clinical trials. Adoption of this COS can improve the value of future uveitis clinical trials and reduce noninformative research. Some of the outcomes identified do not yet have internationally agreed upon methods for measurement and should be the subject of future international consensus development

    Long-Term Safety and Efficacy of Adalimumab in Patients with Noninfectious Intermediate Uveitis, Posterior Uveitis, or Panuveitis

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    Purpose: To evaluate long-term efficacy and safety of extended treatment with adalimumab in patients with noninfectious intermediate, posterior, or panuveitis. Design: Open-label, multicenter, phase 3 extension study (VISUAL III). Participants: Adults who had completed a randomized, placebo-controlled phase 3 parent trial (VISUAL I or II) without treatment failure (inactive uveitis) or who discontinued the study after meeting treatment failure criteria (active uveitis). Methods: Patients received subcutaneous adalimumab 40 mg every other week. Data were collected for ≤ 362 weeks. Adverse events (AEs) were recorded until 70 days after the last dose. Main Outcome Measures: Long-term safety and quiescence; other efficacy variables included inflammatory lesions, anterior chamber cell and vitreous haze grade, macular edema, visual acuity, and dose of uveitis-related systemic corticosteroids. Results: At study entry, 67% of patients (283/424) showed active uveitis and 33% (141/424) showed inactive uveitis; 60 patients subsequently met exclusion criteria, and 364 were included in the intention-to-treat analysis. Efficacy variables were analyzed through week 150, when approximately 50% of patients (214/424) remained in the study. Patients showing quiescence increased from 34% (122/364) at week 0 to 85% (153/180) at week 150. Corticosteroid-free quiescence was achieved by 54% (66/123) and 89% (51/57) of patients with active or inactive uveitis at study entry. Mean daily dose of systemic corticosteroids was reduced from 9.4 ± 17.1 mg/day at week 0 (n = 359) to 1.5 ± 3.9 mg/day at week 150 (n = 181). The percentage of patients who achieved other efficacy variables increased over time for those with active uveitis at study entry and was maintained for those with inactive uveitis. The most frequently reported treatment-emergent AEs of special interest were infections (n = 275; 79 events/100 patient-years [PY]); AEs and serious AEs occurred at a rate of 396 events/100 PY and 15 events/100 PY, respectively. Conclusions: Long-term treatment with adalimumab led to quiescence and reduced corticosteroid use for patients who entered VISUAL III with active uveitis and led to maintenance of quiescence for those with inactive uveitis. AEs were comparable with those reported in the parent trials and consistent with the known safety profile of adalimumab

    The effect of renal denervation on T cells in patients with resistant hypertension

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    (1) BACKGROUND: Sympathetic overactivity is a major contributor to resistant hypertension (RH). According to animal studies, sympathetic overactivity increases immune responses, thereby aggravating hypertension and cardiovascular outcomes. Renal denervation (RDN) reduces sympathetic nerve activity in RH. Here, we investigate the effect of RDN on T-cell signatures in RH. (2) METHODS: Systemic inflammation and T-cell subsets were analyzed in 17 healthy individuals and 30 patients with RH at baseline and 6 months after RDN. (3) RESULTS: The patients with RH demonstrated higher levels of pro-inflammatory cytokines and higher frequencies of CD4+ effector memory (TEM), CD4+ effector memory residential (TEMRA) and CD8+ central memory (TCM) cells than the controls. After RDN, systolic automated office blood pressure (BP) decreased by -17.6 ± 18.9 mmHg. Greater BP reductions were associated with higher CD4+ TEM (r -0.421, p = 0.02) and CD8+ TCM (r -0.424, p = 0.02) frequencies at baseline. The RDN responders, that is, the patients with ≥10mmHg systolic BP reduction, showed reduced pro-inflammatory cytokine levels, whereas the non-responders had unchanged inflammatory activity and higher CD8+ TEMRA frequencies with increased cellular cytokine production. (4) CONCLUSIONS: The pro-inflammatory state of patients with RH is characterized by altered T-cell signatures, especially in non-responders. A detailed analysis of T cells might be useful in selecting patients for RDN

    A genome-wide screening uncovers the role of CCAR2 as an antagonist of DNA end resection

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    There are two major and alternative pathways to repair DNA double-strand breaks: non-homologous end-joining and homologous recombination. Here we identify and characterize novel factors involved in choosing between these pathways; in this study we took advantage of the SeeSaw Reporter, in which the repair of double-strand breaks by homology-independent or -dependent mechanisms is distinguished by the accumulation of green or red fluorescence, respectively. Using a genome-wide human esiRNA (endoribonuclease- prepared siRNA) library, we isolate genes that control the recombination/endjoining ratio. Here we report that two distinct sets of genes are involved in the control of the balance between NHEJ and HR: those that are required to facilitate recombination and those that favour NHEJ. This last category includes CCAR2/DBC1, which we show inhibits recombination by limiting the initiation and the extent of DNA end resection, thereby acting as an antagonist of CtIP

    Shelterin-Like Proteins and Yku Inhibit Nucleolytic Processing of Saccharomyces cerevisiae Telomeres

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    Eukaryotic cells distinguish their chromosome ends from accidental DNA double-strand breaks (DSBs) by packaging them into protective structures called telomeres that prevent DNA repair/recombination activities. Here we investigate the role of key telomeric proteins in protecting budding yeast telomeres from degradation. We show that the Saccharomyces cerevisiae shelterin-like proteins Rif1, Rif2, and Rap1 inhibit nucleolytic processing at both de novo and native telomeres during G1 and G2 cell cycle phases, with Rif2 and Rap1 showing the strongest effects. Also Yku prevents telomere resection in G1, independently of its role in non-homologous end joining. Yku and the shelterin-like proteins have additive effects in inhibiting DNA degradation at G1 de novo telomeres, where Yku plays the major role in preventing initiation, whereas Rif1, Rif2, and Rap1 act primarily by limiting extensive resection. In fact, exonucleolytic degradation of a de novo telomere is more efficient in yku70Δ than in rif2Δ G1 cells, but generation of ssDNA in Yku-lacking cells is limited to DNA regions close to the telomere tip. This limited processing is due to the inhibitory action of Rap1, Rif1, and Rif2, as their inactivation allows extensive telomere resection not only in wild-type but also in yku70Δ G1 cells. Finally, Rap1 and Rif2 prevent telomere degradation by inhibiting MRX access to telomeres, which are also protected from the Exo1 nuclease by Yku. Thus, chromosome end degradation is controlled by telomeric proteins that specifically inhibit the action of different nucleases
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