106 research outputs found

    Structure-activity relationships in a series of antiplasmodial thieno[2,3-b]pyridines.

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    BACKGROUND: Malaria is one of the most prevalent tropical infectious diseases. Since recently cases of artemisinin resistance were reported, novel anti-malarial drugs are required which differ from artemisinins in structure and biological target. The plasmodial glycogen synthase kinase-3 (PfGSK-3) was suggested as a new anti-malarial drug target. 4-Phenylthieno[2,3-b]pyridines were previously identified as selective PfGSK-3 inhibitors with antiplasmodial activity. The present study aims at identifying a molecular position on this scaffold for the attachment of side chains in order to improve solubility and antiplasmodial activity. Furthermore, the role of axial chirality in the compound class for antiplasmodial activity and PfGSK-3 inhibition was investigated. METHODS:4-Phenylthieno[2,3-b]pyridines with substituents in 4-position of the phenyl ring were docked into the ATP binding site of PfGSK-3. The compounds were synthesized employing a Thorpe reaction as final step. The enantiomers of one congener were separated by chiral HPLC. All derivatives were tested for inhibition of asexual erythrocytic stages of transgenic NF54-luc Plasmodium falciparum. Selected compounds with promising antiplasmodial activity were further evaluated for inhibition of HEK293 cells as well as inhibition of isolated PfGSK-3 and HsGSK-3. The kinetic aqueous solubility was assessed by laser nephelometry. RESULTS:The para position at the 4-phenyl ring of the title compounds was identified as a suitable point for the attachment of side chains. While alkoxy substituents in this position led to decreased antiplasmodial activity, alkylamino groups retained antiparasitic potency. The most promising of these congeners (4h) was investigated in detail. This compound is a selective PfGSK-3 inhibitor (versus the human GSK-3 orthologue), and exhibits improved antiplasmodial activity in vitro as well as better solubility in aqueous media than its unsubstituted parent structure. The derivative 4b was separated into the atropisomers, and it was shown that the (+)-enantiomer acts as eutomer. CONCLUSIONS:The attachment of alkylamino side chains leads to the improvement of antiplasmodial activity and aqueous solubility of selective PfGSK-inhibitors belonging to the class of 4-phenylthieno[2,3-b]pyridines. These molecules show axial chirality, a feature of high impact for biological activity. The findings can be exploited for the development of improved selective PfGSK-3 inhibitors

    Enhanced feedback interventions to promote evidence-based blood transfusion guidance and reduce unnecessary use of blood components:The AFFINITIE research programme including two cluster factorial RCTs

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    Background: Blood transfusion is a common but costly treatment. Repeated national audits in the UK suggest that up to one-fifth of transfusions are unnecessary when judged against recommendations for good clinical practice. Audit and feedback seeks to improve patient care and outcomes by comparing clinical care against explicit standards. It is widely used internationally in quality improvement. Audit and feedback generally has modest but variable effects on patient care. A considerable scope exists to improve the impact that audit and feedback has, particularly through head-to-head trials comparing different ways of delivering feedback. Objectives: The AFFINITIE (Development & Evaluation of Audit and Feedback INterventions to Increase evidence-based Transfusion practIcE) programme aimed to design and evaluate enhanced feedback interventions, within a national blood transfusion audit programme, to promote evidence-based guidance and reduce the unnecessary use of blood components. We developed, piloted and refined two feedback interventions, ‘enhanced content’ and ‘enhanced follow-on’ (workstream 1), evaluated the effectiveness and cost-effectiveness of the two feedback interventions compared with standard feedback practice (workstream 2), examined intervention fidelity and contextual influences (workstream 3) and developed general implementation recommendations and tools for other audit and feedback programmes (workstream 4). Design: Interviews, observations and documentary analysis in four purposively sampled hospitals explored contemporary practice and opportunities for strengthening feedback. We developed two interventions: ‘enhanced content’, to improve the clarity and utility of feedback reports, and ‘enhanced follow-on’, to help hospital staff with action-planning (workstream 1). We conducted two linked 2 × 2 factorial cross-sectional cluster-randomised trials within transfusion audits for major surgery and haematological oncology, respectively (workstream 2). We randomised hospital clusters (the organisational level at which hospital transfusion teams operate) to enhanced or standard content or enhanced or standard follow-on. Outcome assessment was masked to assignment. Decision-analytic modelling evaluated the costs, benefits and cost-effectiveness of the feedback interventions in both trials from the perspective of the NHS. A parallel process evaluation used semistructured interviews, documentary analyses and web analytics to assess the fidelity of delivery, receipt and enactment and to identify contextual influences (workstream 3). We explored ways of improving the impact of national audits with their representatives (workstream 4). Setting and participants: All NHS hospital trusts and health boards participating in the National Comparative Audit of Blood Transfusions were invited to take part. Among 189 hospital trusts and health boards screened, 152 hospital clusters participated in the surgical audit. Among 187 hospital trusts and health boards screened, 141 hospital clusters participated in the haematology audit. Interventions: ‘Enhanced content’ aimed to ensure that the content and format of feedback reports were consistent with behaviour change theory and evidence. ‘Enhanced follow-on’ comprised a web-based toolkit and telephone support to facilitate local dissemination, planning and response to feedback. Main outcome measures: Proportions of acceptable transfusions, based on existing evidence and guidance and algorithmically derived from national audit data. Data sources: Trial primary outcomes were derived from manually collected, patient-level audit data. Secondary outcomes included routinely collected data for blood transfusion. Results: With regard to the transfusions in the major surgery audit, 135 (89%) hospital clusters participated from 152 invited. We randomised 69 and 66 clusters to enhanced and standard content, respectively, and 68 and 67 clusters to enhanced and standard follow-on, respectively. We analysed a total of 2222 patient outcomes at 12 months in 54 and 58 (enhanced and standard content, respectively) and 54 and 58 (enhanced and standard follow-on, respectively) hospital clusters. With regard to the haematology audit, 134 hospital clusters (95%) participated from 141 invited. We randomised 66 and 68 clusters to enhanced and standard content, respectively, and 67 clusters to both enhanced and standard follow-on. We analysed a total of 3859 patient outcomes at 12 months in 61 and 61 (enhanced and standard content, respectively) and 63 and 59 (enhanced and standard follow-on) hospital clusters. We found no effect of either of the enhanced feedback interventions in either trial across all outcomes. Incremental enhanced intervention costs ranged from £18 to £248 per site. The enhanced feedback interventions were dominated by the standard intervention in cost-effectiveness analyses. The interventions were delivered as designed and intended, but subsequent local engagement was low. Although the enhancements were generally acceptable, doubts about the credibility of the blood transfusion audits undermined the case for change. Limitations: Limitations included the number of participating clusters; loss to follow-up of trial clusters, reducing statistical power and validity; incomplete audit and cost data contributing to outcome measures; participant self-selection; reporting; missing data related to additional staff activity generated in response to receiving feedback; and recall biases in the process evaluation interviews. Conclusions: The enhanced feedback interventions were acceptable to recipients but were more costly and no more effective than standard feedback in reducing unnecessary use of blood components, and, therefore, should not be recommended on economic grounds. Future work: We have demonstrated the feasibility of embedding ambitious large-scale rigorous research within national audit programmes. Further head-to-head comparisons of different feedback interventions are needed in these programmes to identify cost-effective ways of increasing the impact of the interventions

    Mapping and functional analysis of heterochromatin protein 1 phosphorylation in the malaria parasite Plasmodium falciparum

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    Previous studies in model eukaryotes have demonstrated that phosphorylation of heterochromatin protein 1 (HP1) is important for dynamically regulating its various functions. However, in the malaria parasite Plasmodium falciparum both the function of HP1 phosphorylation and the identity of the protein kinases targeting HP1 are still elusive. In order to functionally analyze phosphorylation of P. falciparum HP1 (PfHP1), we first mapped PfHP1 phosphorylation sites by liquid chromatography tandem mass spectrometry (LC-MS/MS) analysis of native PfHP1, which identified motifs from which potential kinases could be predicted; in particular, several phosphorylated residues were embedded in motifs rich in acidic residues, reminiscent of targets for P. falciparum casein kinase 2 (PfCK2). Secondly, we tested recombinant PfCK2 and a number of additional protein kinases for their ability to phosphorylate PfHP1 in in vitro kinase assays. These experiments validated our prediction that PfHP1 acts as a substrate for PfCK2. Furthermore, LC-MS/MS analysis showed that PfCK2 phosphorylates three clustered serine residues in an acidic motif within the central hinge region of PfHP1. To study the role of PfHP1 phosphorylation in live parasites we used CRISPR/Cas9-mediated genome editing to generate a number of conditional PfHP1 phosphomutants based on the DiCre/LoxP system. Our studies revealed that neither PfCK2-dependent phosphorylation of PfHP1, nor phosphorylation of the hinge domain in general, affect PfHP1's ability to localize to heterochromatin, and that PfHP1 phosphorylation in this region is dispensable for the proliferation of P. falciparum blood stage parasites

    Inhibition of resistance-refractory P. falciparum kinase PKG delivers prophylactic, blood stage, and transmission-blocking antiplasmodial activity

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    The search for antimalarial chemotypes with modes of action unrelated to existing drugs has intensified with the recent failure of first-line therapies across Southeast Asia. Here, we show that the trisubstituted imidazole MMV030084 potently inhibits hepatocyte invasion by Plasmodium sporozoites, merozoite egress from asexual blood stage schizonts, and male gamete exflagellation. Metabolomic, phosphoproteomic, and chemoproteomic studies, validated with conditional knockdown parasites, molecular docking, and recombinant kinase assays, identified cGMP-dependent protein kinase (PKG) as the primary target of MMV030084. PKG is known to play essential roles in Plasmodium invasion of and egress from host cells, matching MMV030084's activity profile. Resistance selections and gene editing identified tyrosine kinase-like protein 3 as a low-level resistance mediator for PKG inhibitors, while PKG itself never mutated under pressure. These studies highlight PKG as a resistance-refractory antimalarial target throughout the Plasmodium life cycle and promote MMV030084 as a promising Plasmodium PKG-targeting chemotype

    What Affects Social Attention? Social Presence, Eye Contact and Autistic Traits

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    Social understanding is facilitated by effectively attending to other people and the subtle social cues they generate. In order to more fully appreciate the nature of social attention and what drives people to attend to social aspects of the world, one must investigate the factors that influence social attention. This is especially important when attempting to create models of disordered social attention, e.g. a model of social attention in autism. Here we analysed participants' viewing behaviour during one-to-one social interactions with an experimenter. Interactions were conducted either live or via video (social presence manipulation). The participant was asked and then required to answer questions. Experimenter eye-contact was either direct or averted. Additionally, the influence of participant self-reported autistic traits was also investigated. We found that regardless of whether the interaction was conducted live or via a video, participants frequently looked at the experimenter's face, and they did this more often when being asked a question than when answering. Critical differences in social attention between the live and video interactions were also observed. Modifications of experimenter eye contact influenced participants' eye movements in the live interaction only; and increased autistic traits were associated with less looking at the experimenter for video interactions only. We conclude that analysing patterns of eye-movements in response to strictly controlled video stimuli and natural real-world stimuli furthers the field's understanding of the factors that influence social attention

    Rare coding variants in PLCG2, ABI3, and TREM2 implicate microglial-mediated innate immunity in Alzheimer's disease

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    We identified rare coding variants associated with Alzheimer’s disease (AD) in a 3-stage case-control study of 85,133 subjects. In stage 1, 34,174 samples were genotyped using a whole-exome microarray. In stage 2, we tested associated variants (P<1×10-4) in 35,962 independent samples using de novo genotyping and imputed genotypes. In stage 3, an additional 14,997 samples were used to test the most significant stage 2 associations (P<5×10-8) using imputed genotypes. We observed 3 novel genome-wide significant (GWS) AD associated non-synonymous variants; a protective variant in PLCG2 (rs72824905/p.P522R, P=5.38×10-10, OR=0.68, MAFcases=0.0059, MAFcontrols=0.0093), a risk variant in ABI3 (rs616338/p.S209F, P=4.56×10-10, OR=1.43, MAFcases=0.011, MAFcontrols=0.008), and a novel GWS variant in TREM2 (rs143332484/p.R62H, P=1.55×10-14, OR=1.67, MAFcases=0.0143, MAFcontrols=0.0089), a known AD susceptibility gene. These protein-coding changes are in genes highly expressed in microglia and highlight an immune-related protein-protein interaction network enriched for previously identified AD risk genes. These genetic findings provide additional evidence that the microglia-mediated innate immune response contributes directly to AD development

    Finishing the euchromatic sequence of the human genome

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    The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

    Impact of opioid-free analgesia on pain severity and patient satisfaction after discharge from surgery: multispecialty, prospective cohort study in 25 countries

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    Background: Balancing opioid stewardship and the need for adequate analgesia following discharge after surgery is challenging. This study aimed to compare the outcomes for patients discharged with opioid versus opioid-free analgesia after common surgical procedures.Methods: This international, multicentre, prospective cohort study collected data from patients undergoing common acute and elective general surgical, urological, gynaecological, and orthopaedic procedures. The primary outcomes were patient-reported time in severe pain measured on a numerical analogue scale from 0 to 100% and patient-reported satisfaction with pain relief during the first week following discharge. Data were collected by in-hospital chart review and patient telephone interview 1 week after discharge.Results: The study recruited 4273 patients from 144 centres in 25 countries; 1311 patients (30.7%) were prescribed opioid analgesia at discharge. Patients reported being in severe pain for 10 (i.q.r. 1-30)% of the first week after discharge and rated satisfaction with analgesia as 90 (i.q.r. 80-100) of 100. After adjustment for confounders, opioid analgesia on discharge was independently associated with increased pain severity (risk ratio 1.52, 95% c.i. 1.31 to 1.76; P &lt; 0.001) and re-presentation to healthcare providers owing to side-effects of medication (OR 2.38, 95% c.i. 1.36 to 4.17; P = 0.004), but not with satisfaction with analgesia (beta coefficient 0.92, 95% c.i. -1.52 to 3.36; P = 0.468) compared with opioid-free analgesia. Although opioid prescribing varied greatly between high-income and low- and middle-income countries, patient-reported outcomes did not.Conclusion: Opioid analgesia prescription on surgical discharge is associated with a higher risk of re-presentation owing to side-effects of medication and increased patient-reported pain, but not with changes in patient-reported satisfaction. Opioid-free discharge analgesia should be adopted routinely

    Brf1 loss and not overexpression disrupts tissues homeostasis in the intestine, liver and pancreas

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    RNA polymerase III (Pol-III) transcribes tRNAs and other small RNAs essential for protein synthesis and cell growth. Pol-III is deregulated during carcinogenesis; however, its role in vivo has not been studied. To address this issue, we manipulated levels of Brf1, a Pol-III transcription factor that is essential for recruitment of Pol-III holoenzyme at tRNA genes in vivo. Knockout of Brf1 led to embryonic lethality at blastocyst stage. In contrast, heterozygous Brf1 mice were viable, fertile and of a normal size. Conditional deletion of Brf1 in gastrointestinal epithelial tissues, intestine, liver and pancreas, was incompatible with organ homeostasis. Deletion of Brf1 in adult intestine and liver induced apoptosis. However, Brf1 heterozygosity neither had gross effects in these epithelia nor did it modify tumorigenesis in the intestine or pancreas. Overexpression of BRF1 rescued the phenotypes of Brf1 deletion in intestine and liver but was unable to initiate tumorigenesis. Thus, Brf1 and Pol-III activity are absolutely essential for normal homeostasis during development and in adult epithelia. However, Brf1 overexpression or heterozygosity are unable to modify tumorigenesis, suggesting a permissive, but not driving role for Brf1 in the development of epithelial cancers of the pancreas and gut
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