2,630 research outputs found

    Functional role of a consensus peptide which is common to α-, β-, and γ-tubulin, to actin and centractin, to phytochrome A, and to the TCP1α chaperonin protein

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    AbstractThe TRiC (TCP1 Ring Complex) chaperonin complex participates in the functional folding of actin, centractin, α-,β-,γ-tubulin, and phytochrome. Each of the cytoskeletal proteins contain a peptide, RK(A,C,T)F/KRAF, located towards the C-terminus, which is homologous to a TCP1α peptide, while the equivalent phytochrome peptide (RLKAF in certain isoforms) is very similar to the KLRAF peptide of TCP1α. We propose that this TCP1α peptide binds to the nascent polypeptides as they emerge from the ribosome, that this binding restricts the folding pathway, and that the TCP1α peptide is subsequently displaced by the synthesis of the consensus peptide. This hypothesis is strongly supported by the crystallographic structure of actin

    Assembly of microtubules with ATP: evidence that only a fraction of the protein is assembly-competent

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    AbstractChick brain microtubule protein can be assembled in vitro with ATP, although the extent of assembly is less than that with GTP. The ATP-induced assembly is not the result of generation of GTP by the co-purifying nucleoside diphosphate kinase. Neither an observed increase in the critical concentration nor the phosphorylation of MAP2 can account for the decreased extent of assembly. However, whereas microtubules are formed with both ATP and GTP, incubation with ATP yields additional filaments and polymorphic aggregates. The results demonstrate that of the total protein which can be assembled into microtubules by GTP, about 25–35% is assembled into other structural forms in the presence of ATP

    Alternative soot detection strategies for application in aero-engine test-beds : assessment of the performance and uncertainties of time-integrated LII

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    We describe a laser induced incandescence (LII) measurement system for 2D mapping of non-volatile particulate matter (soot) in full-scale aero-engine exhausts. Simulation allows us to quantify the sensitivity of the measurement to variation in physical properties such as primary particle size, over a range of laser fluences and as a function of beam diameter. We discuss the implications of our results for optimisation and calibration of soot imaging in exhaust streams

    Enantioselective synthesis of bicyclo[3.n.1]alkanes by chiral phosphoric acid-catalyzed desymmetrizing Michael cyclizations

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    2,2-Disubstituted cyclic 1,3-diketones containing a tethered electron-deficient alkene undergo chiral phosphoric acid-catalyzed desymmetrizing Michael cyclizations to give bridged bicyclic products in high enantioselectivities.</p

    A Joint Fermi-GBM and LIGO/Virgo Analysis of Compact Binary Mergers from the First and Second Gravitational-wave Observing Runs

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    We present results from offline searches of Fermi Gamma-ray Burst Monitor (GBM) data for gamma-ray transients coincident with the compact binary coalescences observed by the gravitational-wave (GW) detectors Advanced LIGO and Advanced Virgo during their first and second observing runs. In particular, we perform follow-up for both confirmed events and low significance candidates reported in the LIGO/Virgo catalog GWTC-1. We search for temporal coincidences between these GW signals and GBM-triggered gamma-ray bursts (GRBs). We also use the GBM Untargeted and Targeted subthreshold searches to find coincident gamma-rays below the onboard triggering threshold. This work implements a refined statistical approach by incorporating GW astrophysical source probabilities and GBM visibilities of LIGO/Virgo sky localizations to search for cumulative signatures of coincident subthreshold gamma-rays. All search methods recover the short gamma-ray burst GRB 170817A occurring ~1.7 s after the binary neutron-star merger GW170817. We also present results from a new search seeking GBM counterparts to LIGO single-interferometer triggers. This search finds a candidate joint event, but given the nature of the GBM signal and localization, as well as the high joint false alarm rate of 1.1 × 10−6 Hz, we do not consider it an astrophysical association. We find no additional coincidences

    Sexual risk reduction interventions for patients attending sexual health clinics: a mixed-methods feasibility study

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    Background: Sexually transmitted infections (STIs) continue to represent a major public health challenge. There is evidence that behavioural interventions to reduce risky sexual behaviours can reduce STI rates in patients attending sexual health (SH) services. However, it is not known if these interventions are effective when implemented at scale in SH settings in England. Objectives: The study had two main objectives: 1. develop and pilot a package of evidence-based sexual risk reduction interventions that can be delivered through SH services; 2. assess the feasibility of conducting a randomised controlled trial (RCT) to determine effectiveness against usual care. Design: The project was a multi-stage mixed methods study, with developmental and pilot RCT phases. Preparatory work included a systematic review; analysis of national surveillance data, and development of a triage algorithm; interviews and surveys with SH staff and patients to identify, select and adapt interventions. A pilot cluster RCT was planned for eight SH clinics; the intervention would be offered in four clinics, with qualitative and process evaluation to assess feasibility and acceptability. Four clinics acted as controls; in all clinics, participants would be consented to a 6-week follow-up STI screen. Setting: SH clinics in England. Participants: Young people (aged 16-25 years old) and men who have sex with men. Intervention: A three-part intervention package: 1. triage tool to score patients as high or low risk of STI infection using routine data; 2. a study-designed webpage with tailored sexual health information for all patients, regardless of risk; 3. a brief one-to-one session based on motivational interviewing for high risk patients. Main outcome measures: The three outcomes were: acceptability of the intervention to patients and SH providers; feasibility of delivering the interventions within existing resources; and feasibility of obtaining follow-up data on STI diagnoses (primary outcome in a full trial). Results: We identified 33 relevant trials from the systematic review, including: videos, peer support, digital, and brief one-to-one sessions. Patients and SH providers showed preferences for one-to-one and digital interventions, and providers indicated these intervention types could feasibly be implemented in their settings. There were no appropriate digital interventions that could be adapted in time for the pilot; therefore, we created a placeholder for the purposes of the pilot. The intervention package was piloted in two SH settings, rather than the planned four. Several barriers were found to intervention implementation, including a lack of trained staff time and clinic space. The intervention package was theoretically acceptable, but we observed poor engagement. We recruited patients from six clinics for the follow-up, rather than eight. The completion rate for follow-up was lower than anticipated (16% versus 46%). Limitations: Fewer clinics were included in the pilot than planned limiting the ability to make strong conclusions on RCT feasibility. Conclusion: We were unable to conclude whether a definitive RCT would be feasible due to challenges in implementation of a pilot, but have laid the groundwork for future research in the area

    Scoring system for renal pathology in Fabry disease: report of the International Study Group of Fabry Nephropathy (ISGFN)

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    Background. In Fabry nephropathy, alpha-galactosidase deficiency leads to accumulation of glycosphingolipids in all kidney cell types, proteinuria and progressive loss of kidney function. Methods. An international working group of nephrologists from 11 Fabry centres identified adult Fabry patients, and pathologists scored histologic changes on renal biopsies. A standardized scoring system was developed with a modified Delphi technique assessing 59 Fabry nephropathy cases. Each case was scored independently of clinical information by at least three pathologists with an average final score reported. Results. We assessed 35 males (mean age 36.4 years) and 24 females (43.9 years) who mostly had clinically mild Fabry nephropathy. The average serum creatinine was 1.3mg/dl (114.9 μmol/l); estimated glomerular filtration rate was 81.7 ml/min/1.73 m2 and urine protein to creatinine ratio was 1.08 g/g (122.0 mg/mmol). Males had greater podocyte vacuolization on light microscopy (mean score) and glycosphingolipid inclusions on semi-thin sections than females. Males also had significantly more proximal tubule, peritubular capillary and vascular intimal inclusions. Arteriolar hyalinosis was similar, but females had significantly more arterial hyalinosis. Chronic kidney disease stage correlated with arterial and glomerular sclerosis scores. Significant changes, including segmental and global sclerosis, and interstitial fibrosis were seen even in patients with stage 1-2 chronic kidney disease with minimal proteinuria. Conclusions. The development of a standardized scoring system of both disease-specific lesions, i.e. lipid deposition related, and general lesions of progression, i.e. fibrosis and sclerosis, showed a spectrum of histologic appearances even in early clinical stage of Fabry nephropathy. These findings support the role of kidney biopsy in the baseline evaluation of Fabry nephropathy, even with mild clinical disease. The scoring system will be useful for longitudinal assessment of prognosis and responses to therapy for Fabry nephropath

    Loneliness, social support and cardiovascular reactivity to laboratory stress

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    Self-reported or explicit loneliness and social support have been inconsistently associated with cardiovascular reactivity (CVR) to stress. The present study aimed to adapt an implicit measure of loneliness, and use it alongside the measures of explicit loneliness and social support, to investigate their correlations with CVR to laboratory stress. Twenty-five female volunteers aged between 18 and 39 years completed self-reported measures of loneliness and social support, and an Implicit Association Test (IAT) of loneliness. The systolic blood pressure (SBP), diastolic blood pressure (DBP) and heart rate (HR) reactivity indices were measured in response to psychosocial stress induced in the laboratory. Functional support indices of social support were significantly correlated with CVR reactivity to stress. Interestingly, implicit, but not explicit, loneliness was significantly correlated with DBP reactivity after one of the stressors. No associations were found between structural support and CVR indices. Results are discussed in terms of validity of implicit versus explicit measures and possible factors that affect physiological outcomes

    Delivering strong 1H nuclear hyperpolarization levels and long magnetic lifetimes through signal amplification by reversible exchange

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    Hyperpolarization turns typically weak NMR and MRI responses into strong signals so that ordinarily impractical measurements become possible. The potential to revolutionize analytical NMR and clinical diagnosis through this approach reflect this area's most compelling outcomes. Methods to optimize the low cost parahydrogen based approach signal amplification by reversible exchange (SABRE) with studies on a series of biologically relevant nicotinamides and methyl nicotinates are detailed. These procedures involve specific 2H-labelling in both the agent and catalyst and achieve polarization lifetimes of ca. 2 minutes with 50% polarization in the case of 4,6-d2-methylnicotinate. As a 1.5 T hospital scanner has an effective 1H polarization level of just 0.0005% this strategy should result in compressed detection times for chemically discerning measurements that probe disease. To demonstrate this techniques generality, we exemplify further studies on a range of pyridazine, pyrimidine, pyrazine and isonicotinamide analogues that feature as building blocks in biochemistry and many disease treating drugs

    Success of an International Learning Health Care System in Hematopoietic Cell Transplantation: The American Society of Blood and Marrow Transplantation Clinical Case Forum

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    The ASBMT Clinical Case Forum (CCF) was launched in 2014 as an online secure tool to enhance interaction and communication among hematopoietic cell transplantation (HCT) professionals worldwide through the discussion of challenging clinical care issues. After 14 months, we reviewed clinical and demographical data on cases posted in the CCF from 1/29/2014 to 3/18/2015. A total of 137 cases were posted during the study period. Ninety-two cases (67%) were allogeneic HCT, 29 (21%) autologous HCT and in 16 (12%) the type of transplant (auto vs. allo) was still under consideration. The diseases most frequently discussed included non-Hodgkin lymphoma (NHL; n = 30, 22%), acute myeloid leukemia (AML; n = 23, 17%) and multiple myeloma (MM; n = 20, 15%). When compared with the US transplant activity reported by the US Department of Health and Human Services, NHL and acute lymphoblastic leukemia cases were overrepresented in the CCF while myeloma was underrepresented (P < 0.001). A total of 259 topics were addressed in the CCF with a median of two topics/case (range 1-6). Particularly common topics included whether transplant was indicated (n = 57, 41%), conditioning regimen choice (n = 44, 32%), and post-HCT complications after day 100 (n = 43, 31%). The ASBMT CCF is a successful tool for collaborative discussion of complex cases in the HCT community worldwide and may allow identification of areas of controversy or unmet need from clinical, educational and research perspectives
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