1,307 research outputs found

    4S-Hydroxylation of insulin at ProB28 accelerates hexamer dissociation and delays fibrillation

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    Daily injections of insulin provide lifesaving benefits to millions of diabetics. But currently available prandial insulins are suboptimal: The onset of action is delayed by slow dissociation of the insulin hexamer in the subcutaneous space, and insulin forms amyloid fibrils upon storage in solution. Here we show, through the use of non-canonical amino acid mutagenesis, that replacement of the proline residue at position 28 of the insulin B-chain (ProB28) by (4S)-hydroxyproline (Hzp) yields an active form of insulin that dissociates more rapidly, and fibrillates more slowly, than the wild-type protein. Crystal structures of dimeric and hexameric insulin preparations suggest that a hydrogen bond between the hydroxyl group of Hzp and a backbone amide carbonyl positioned across the dimer interface may be responsible for the altered behavior. The effects of hydroxylation are stereospecific; replacement of ProB28 by (4R)-hydroxyproline (Hyp) causes little change in the rates of fibrillation and hexamer disassociation. These results demonstrate a new approach that fuses the concepts of medicinal chemistry and protein design, and paves the way to further engineering of insulin and other therapeutic proteins

    Nasal airflow and odorant transport modeling in patients with chronic rhinosimusitis

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    Poster presentation at Association for Chemoreception Sciences (ACHEMS) in Sarasota Florida April 25-29, 2007. Introduction: Our on-going clinical project aims to quantify the conductive mechanism contributing toolfactory loss in chronic rhinosinusitis (CRS) patients, in addition to other inflammatory causes(see Yee, et al, 200 and Feng, et al, 203). CRS, a common disease affecting 32 millionAmericans annually, is reportedly associated with at least 15% of all olfactory losses. Airwayconstriction as a result of inflammation or the presence of polyps may limit odor access to thereceptor sites and lead to olfactory dysfunction. As yet, the functional impact of various nasalobstructions as sequelae to CRS and their treatment outcomes have not been successfullyindexed by any existing clinical tools, such as acoustic rhinometry, or rhinomanometry.Computational fluid dynamics (CFD) techniques have shown great promises to simulate nasalairflow and predict odorant delivery rates to the olfactory epithelium based on CT scans. In thisreport, we provide additional support for the hypothesis that the CFD calculation is a betterpredictor of olfactory sensitivity among CRS patients than are conventional methods

    Assessment of smoking status based on cotinine levels in nasal lavage fluid

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    Cotinine is a principal metabolite of nicotine with a substantially longer half-life, and cotinine levels in saliva, urine or serum are widely used to validate self-reported smoking status. The nasal cavity and olfactory system are directly exposed to tobacco smoke in smokers and in non-smokers who live with or work around smokers. However, despite the potential for a direct impact of tobacco smoke on the nasal epithelium and olfactory neurons, no prior studies have assessed cotinine levels in nasal mucus. We sought to determine whether cotinine levels in nasal lavage fluid (NLF) would provide a reasonable estimate of smoke exposure. We assayed cotinine using a competitive immunoassay in NLF from 23 smokers, 10 non-smokers exposed to tobacco smoke (ETS) and 60 non-smokers who did not report smoke exposure. NLF cotinine levels were significantly higher in smokers than in non-smokers, regardless of their exposure to ambient tobacco smoke. Cotinine levels in this small group of exposed non-smokers were not significantly different than those of non-exposed non-smokers. A cutoff of 1 ng/ml provided a sensitivity of 91% and a specificity of 99% for smoking status in this sample. Data were consistent with self-reported smoking status, and a cutoff of 1.0 ng/ml NLF cotinine may be used to classify smoking status. While saliva is the most easily obtained body fluid, NLF can be used to provide an objective and precise indication of smoking status and more directly reflects smoke exposure in the nasal and olfactory mucosa

    Experimental Determination of Salinity, Temperature, Growth, and Metabolic Effects on Shell Isotope Chemistry of Mytilus Edulis Collected from Maine and Greenland

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    To study the effects of temperature, salinity, and life processes (growth rates, size, metabolic effects, and physiological/ genetic effects) on newly precipitated bivalve carbonate, we quantified shell isotopic chemistry of adult and juvenile animals of the intertidal bivalve Mytilus edulis (Blue mussel) collected alive from western Greenland and the central Gulf of Maine and cultured them under controlled conditions. Data for juvenile and adult M. edulis bivalves cultured in this study, and previously by Wanamaker et al. (2006), yielded statistically identical paleotemperature relationships. On the basis of these experiments we have developed a species-specific paleotemperature equation for the bivalve M. edulis [T degrees C = 16.28 (+/- 0.10) -4.57 (+/- 0.15) {delta(18)O(c) VPBD - delta(18)O(w) VSMOW} + 0.06 (+/- 0.06) {delta(18)O(c) VPBD - delta(18)O(w) VSMOW}(2); r(2) = 0.99; N = 323; p \u3c 0.0001]. Compared to the Kim and O\u27Neil (1997) inorganic calcite equation, M. edulis deposits its shell in isotope equilibrium (delta(18)O(calcite)) with ambient water. Carbon isotopes (delta(13)C(calcite)) from sampled shells were substantially more negative than predicted values, indicating an uptake of metabolic carbon into shell carbonate, and delta(13)C(calcite) disequilibrium increased with increasing salinity. Sampled shells of M. edulis showed no significant trends in delta(18)O(calcite) based on size, cultured growth rates, or geographic collection location, suggesting that vital effects do not affect delta(18)O(calcite) in M. edulis. The broad modern and paleogeographic distribution of this bivalve, its abundance during the Holocene, and the lack of an intraspecies physiologic isotope effect demonstrated here make it an ideal nearshore paleoceanographic proxy throughout much of the North Atlantic Ocean

    The Hubble Space Telescope Extragalactic Distance Scale Key Project. X. The Cepheid Distance to NGC 7331

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    The distance to NGC 7331 has been derived from Cepheid variables observed with HST/WFPC2, as part of the Extragalactic Distance Scale Key Project. Multi-epoch exposures in F555W (V) and F814W (I), with photometry derived independently from DoPHOT and DAOPHOT/ALLFRAME programs, were used to detect a total of 13 reliable Cepheids, with periods between 11 and 42 days. The relative distance moduli between NGC 7331 and the LMC, imply an extinction to NGC 7331 of A_V = 0.47+-0.15 mag, and an extinction-corrected distance modulus to NGC 7331 of 30.89+-0.14(random) mag, equivalent to a distance of 15.1 Mpc. There are additional systematic uncertainties in the distance modulus of +-0.12 mag due to the calibration of the Cepheid Period-Luminosity relation, and a systematic offset of +0.05+-0.04 mag if we applied the metallicity correction inferred from the M101 results of Kennicutt et al 1998.Comment: To be published in The Astrophysical Journal, 1998 July 1, v501 note: Figs 1 and 2 (JPEG files) and Fig 7 (multipage .eps file) need to be viewed/printed separatel

    Bridging the Gap Between Practice Guidelines and the Therapy Room: Community-Derived Practice Adaptations for Psychological Services with Transgender and Gender Diverse Adults in the Central United States

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    Individuals who identify as transgender and gender diverse (TGD) are presenting at mental health clinicians’ offices with increasing frequency. Many TGD clients are seeking care related to affirming their gender identity but also may present with anxiety, depression, trauma, substance abuse, or other problems forwhich a clinician may commonly provide services. Some clinicians may hesitate to accept TGD clients into their practice if they have little specialized training to work with this population in an affirming manner, especially in more underserved areas where a generalist practice is the norm. Numerous professional associations and experts have developed guidelines for affirmative behavioral health care for TGDpeople.However, what is needed are community-informed recommendations to bridge from the official guidelines to clinicians’ in-session activities. The Trans Collaborations Practice Adaptations for Psychological Interventions for Transgender and Gender Diverse Adults are derived from iterative interviews with TGD community members and affirming mental health clinicians in the Central United States. The 12 practice adaptations are intended to guide clinicians to adapt their usual treatment approach to be TGD affirming, especially in underserved and rural areas. The practice adaptations cover numerous aspects of practice including the office setting and paperwork, understanding gender identity and incorporating it into the case conceptualization, therapist’s self-awareness, and referrals. The Trans Collaborations Practice Adaptations will help clinicians work confidently and competently with adult TGD clients, regardless of the presenting problem, to ensure TGD communities receive the best interventions for their behavioral health concerns

    System Dynamics modelling to formulate policy interventions to optimise antibiotic prescribing in hospitals

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    © 2020 The Author(s). This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.Multiple strategies have been used in the National Health System (NHS) in England to reduce inappropriate antibiotic prescribing and consumption in order to tackle antimicrobial resistance. These strategies have included, among others, restricting dispensing, introduction of prescribing guidelines, use of clinical audit, and performance reviews as well as strategies aimed at changing the prescribing behaviour of clinicians. However, behavioural interventions have had limited effect in optimising doctors’ antibiotic prescribing practices. This study examines the determinants of decision-making for antibiotic prescribing in hospitals in the NHS. A system dynamics model was constructed to capture structural and behavioural influences to simulate doctors’ prescribing practices. Data from the literature, patient records, healthcare professional interviews and survey responses were used to parameterise the model. The scenario simulation shows maximum improvements in guideline compliance are achieved when compliance among senior staff is increased, combined with fast laboratory turnaround of blood cultures, and microbiologist review. Improving guideline compliance of junior staff alone has limited impact. This first use of system dynamics modelling to study antibiotic prescribing decision-making demonstrates the applicability of the methodology for design and evaluation of future policies and interventions.Peer reviewe
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