35 research outputs found

    Bispecific FpFs: a versatile tool for preclinical antibody development

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    We previously described FpFs [1 with combining low line] (Fab–PEG–Fab) as binding mimetics of IgGs. FpFs are prepared with di(bis-sulfone) conjugation reagents [3 with combining low line] that undergo disulfide rebridging conjugation with the accessible disulfide of each Fab (Scheme 1). We have now prepared bispecific FpFs [2 with combining low line] (bsFpF and Fab1–PEG–Fab2) as potential bispecific antibody mimetics with the intent that bsFpFs could be used in preclinical antibody development since sourcing bispecific antibodies may be challenging during preclinical research. The di(bis-sulfone) reagent [3 with combining low line] was first used to prepare a bsFpF [2 with combining low line] by the sequential conjugation of a first Fab and then a second Fab to another target (Scheme 2). Seeking to improve bsFpF synthesis, the asymmetric conjugation reagent, bis-sulfone bis-sulfide [1 with combining low line][6 with combining low line], with different thiol conjugation reactivities at each terminus (Scheme 4) was examined and the bsFpFs appeared to be formed at similar conversion to the di(bis-sulfone) reagent [3 with combining low line]. To explore the advantages of using common intermediates in the preparation of bsFpF families, we investigated bsFpF synthesis with a protein conjugation–ligation approach (Scheme 5). Reagents with a bis-sulfone moiety for conjugation on one PEG terminus and a ligation moiety on the other terminus were examined. Bis-sulfone PEG trans-cyclooctene (TCO) [2 with combining low line][8 with combining low line] and bis-sulfone PEG tetrazine (Tz) [3 with combining low line][0 with combining low line] were used to prepare several bsFpFs targeting various therapeutic targets (TNF-α, IL6R, IL17, and VEGF) and tissue affinity targets (hyaluronic acid and collagen II). Surface plasmon resonance (SPR) binding studies indicated that there was little difference between the dissociation rate constant (kd) for the unmodified Fab, mono-conjugated PEG–Fab and the corresponding Fab in a bsFpF. The Fab association rate (ka) in the bsFpF was slower than for PEG–Fab, which may be because of mass differences that influence SPR results. These observations suggest that each Fab will bind to its target independently of the other Fab and that bsFpF binding profiles can be estimated using the corresponding PEG–Fab conjugates

    The preparation of HEMA-MPC films for ocular drug delivery

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    There is a need to prolong drug residence time using a biocompatible formulation in the subconjunctival space after surgery to treat glaucoma. Drug releasing discs were prepared with 2-(hydroxyethyl)methacrylate (HEMA) and 2-methacryloyl-oxyethyl phosphorylcholine (MPC). The ratio of bound water (Wb) to free water (Wf) ratio increased from 1:0.3 to 1:6.8 with increasing MPC (0 to 50%, w/w). The optimal balance between water content, SR and mechanical strength were obtained with 10% MPC (w/w) hydrogels. Water-alcohol mixtures were examined to facilitate loading of poorly soluble drugs, and they showed greater hydrogel swelling than either water or alcohol alone. The SR was 1.2 ± 0.02 and 3.3 ± 0.1 for water and water:ethanol (1:1) respectively. HEMA-MPC (10%) discs were loaded with dexamethasone using either water:ethanol (1:1) or methanol alone. Drug release was examined in an outflow rig model that mimics the subconjunctival space in the eye. Dexamethasone loading increased from 0.3 to 1.9 mg/disc when the solvent was changed from water:ethanol (1:1) to methanol with the dexamethasone half-life (t½) increasing from 1.9 to 9.7 days respectively. These encouraging results indicate that HEMA-MPC hydrogels have the potential to sustain the residence time of a drug in the subconjunctival space of the eye

    Genome-wide association and Mendelian randomisation analysis provide insights into the pathogenesis of heart failure

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    Heart failure (HF) is a leading cause of morbidity and mortality worldwide. A small proportion of HF cases are attributable to monogenic cardiomyopathies and existing genome-wide association studies (GWAS) have yielded only limited insights, leaving the observed heritability of HF largely unexplained. We report results from a GWAS meta-analysis of HF comprising 47,309 cases and 930,014 controls. Twelve independent variants at 11 genomic loci are associated with HF, all of which demonstrate one or more associations with coronary artery disease (CAD), atrial fibrillation, or reduced left ventricular function, suggesting shared genetic aetiology. Functional analysis of non-CAD-associated loci implicate genes involved in cardiac development (MYOZ1, SYNPO2L), protein homoeostasis (BAG3), and cellular senescence (CDKN1A). Mendelian randomisation analysis supports causal roles for several HF risk factors, and demonstrates CAD-independent effects for atrial fibrillation, body mass index, and hypertension. These findings extend our knowledge of the pathways underlying HF and may inform new therapeutic strategies

    Measurement of the Positive Muon Anomalous Magnetic Moment to 0.46 ppm

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    We present the first results of the Fermilab Muon g-2 Experiment for the positive muon magnetic anomaly aμ(gμ2)/2a_\mu \equiv (g_\mu-2)/2. The anomaly is determined from the precision measurements of two angular frequencies. Intensity variation of high-energy positrons from muon decays directly encodes the difference frequency ωa\omega_a between the spin-precession and cyclotron frequencies for polarized muons in a magnetic storage ring. The storage ring magnetic field is measured using nuclear magnetic resonance probes calibrated in terms of the equivalent proton spin precession frequency ω~p{\tilde{\omega}'^{}_p} in a spherical water sample at 34.7^{\circ}C. The ratio ωa/ω~p\omega_a / {\tilde{\omega}'^{}_p}, together with known fundamental constants, determines aμ(FNAL)=116592040(54)×1011a_\mu({\rm FNAL}) = 116\,592\,040(54)\times 10^{-11} (0.46\,ppm). The result is 3.3 standard deviations greater than the standard model prediction and is in excellent agreement with the previous Brookhaven National Laboratory (BNL) E821 measurement. After combination with previous measurements of both μ+\mu^+ and μ\mu^-, the new experimental average of aμ(Exp)=116592061(41)×1011a_\mu({\rm Exp}) = 116\,592\,061(41)\times 10^{-11} (0.35\,ppm) increases the tension between experiment and theory to 4.2 standard deviationsComment: 10 pages; 4 figure

    Multi-trait genome-wide association study identifies new loci associated with optic disc parameters

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    A new avenue of mining published genome-wide association studies includes the joint analysis of related traits. The power of this approach depends on the genetic correlation of traits, which reflects the number of pleiotropic loci, i.e. genetic loci influencing multiple traits. Here, we applied new meta-analyses of optic nerve head (ONH) related traits implicated in primary open-angle glaucoma (POAG); intraocular pressure and central corneal thickness using Haplotype reference consortium imputations. We performed a multi-trait analysis of ONH parameters cup area, disc area and vertical cup-disc ratio. We uncover new variants; rs11158547 in PPP1R36-PLEKHG3 and rs1028727 near SERPINE3 at genome-wide significance that replicate in independent Asian cohorts imputed to 1000 Genomes. At this point, validation of these variants in POAG cohorts is hampered by the high degree of heterogeneity. Our results show that multi-trait analysis is a valid approach to identify novel pleiotropic variants for ONH

    Rising rural body-mass index is the main driver of the global obesity epidemic in adults

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    Body-mass index (BMI) has increased steadily in most countries in parallel with a rise in the proportion of the population who live in cities 1,2 . This has led to a widely reported view that urbanization is one of the most important drivers of the global rise in obesity 3�6 . Here we use 2,009 population-based studies, with measurements of height and weight in more than 112 million adults, to report national, regional and global trends in mean BMI segregated by place of residence (a rural or urban area) from 1985 to 2017. We show that, contrary to the dominant paradigm, more than 55 of the global rise in mean BMI from 1985 to 2017�and more than 80 in some low- and middle-income regions�was due to increases in BMI in rural areas. This large contribution stems from the fact that, with the exception of women in sub-Saharan Africa, BMI is increasing at the same rate or faster in rural areas than in cities in low- and middle-income regions. These trends have in turn resulted in a closing�and in some countries reversal�of the gap in BMI between urban and rural areas in low- and middle-income countries, especially for women. In high-income and industrialized countries, we noted a persistently higher rural BMI, especially for women. There is an urgent need for an integrated approach to rural nutrition that enhances financial and physical access to healthy foods, to avoid replacing the rural undernutrition disadvantage in poor countries with a more general malnutrition disadvantage that entails excessive consumption of low-quality calories. © 2019, The Author(s)

    The effects of growth factors and antiproliferative agents on ocular fibroblasts and wound healing after glaucoma filtration surgery

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    SIGLEAvailable from British Library Document Supply Centre-DSC:DX195836 / BLDSC - British Library Document Supply CentreGBUnited Kingdo

    Dynamic protrusive cell behaviour generates force and drives early matrix contraction by fibroblasts

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    We investigated the cellular mechanisms underlying force generation and matrix contraction, using human corneal, Tenon's and scleral fibroblasts in a standard collagen matrix. We used timelapse light and confocal reflection microscopy to analyse concomitantly cell behaviour and matrix remodeling during contraction and devised a novel index to quantify dynamic cell behaviour in 3D. Based on the previously described culture force monitor, a novel simultaneous imaging and micro-culture force monitor system (SIM–CFM) was developed to measure the mechanical strain generated during matrix contraction whilst simultaneously recording cell and matrix behaviour. Ocular fibroblasts show marked differences in macroscopic matrix contraction profiles, with corneal fibroblasts inducing the strongest, and scleral the weakest, contraction. We identified four factors that determine the early matrix contraction profile: 1) cell size, 2) intrinsic cellular force, 3) dynamic cell protrusive activity and 4) net pericellular matrix displacement. Intrinsic cellular force and dynamic activity appear to be independent unique characteristics of each cell type and might serve as predictors of matrix contraction. The identification of these factors raises the fundamental new possibilities of predicting the ability of tissues to contract and scar and of modulating tissue contraction by targeting intracellular pathways linked to protrusive activity and force generation
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