1,881 research outputs found
African-American Parents: A New Partnership with Higher Education
A close association of African- American parents and universities can benefit the parents, the universities, and African-American students
A screen for Plasmodium falciparum sporozoite surface protein binding to human hepatocyte surface receptors identifies novel host–pathogen interactions
Background: Sporozoite invasion of hepatocytes is an essential step in the Plasmodium life-cycle and has similarities, at the cellular level, to merozoite invasion of erythrocytes. In the case of the Plasmodium blood-stage, efforts to identify host–pathogen protein–protein interactions have yielded important insights including vaccine candidates. In the case of sporozoite-hepatocyte invasion, the host–pathogen protein–protein interactions involved are poorly understood. Methods: To gain a better understanding of the protein–protein interaction between the sporozoite ligands and host receptors, a systematic screen was performed. The previous Plasmodium falciparum and human surface protein ectodomain libraries were substantially extended, resulting in the creation of new libraries comprising 88 P. falciparum sporozoite protein coding sequences and 182 sequences encoding human hepatocyte surface proteins. Having expressed recombinant proteins from these sequences, a plate-based assay was used, capable of detecting low affinity interactions between recombinant proteins, modified for enhanced throughput, to screen the proteins for interactions. The novel interactions identified in the screen were characterized biochemically, and their essential role in parasite invasion was further elucidated using antibodies and genetically manipulated Plasmodium parasites. Results: A total of 7540 sporozoite-hepatocyte protein pairs were tested under conditions capable of detecting interactions of at least 1.2 µM KD. An interaction between the human fibroblast growth factor receptor 4 (FGFR4) and the P. falciparum protein Pf34 is identified and reported here, characterizing its affinity and demonstrating the blockade of the interaction by reagents, including a monoclonal antibody. Furthermore, further interactions between Pf34 and a second P. falciparum rhoptry neck protein, PfRON6, and between human low-density lipoprotein receptor (LDLR) and the P. falciparum protein PIESP15 are identified. Conditional genetic deletion confirmed the essentiality of PfRON6 in the blood-stage, consistent with the important role of this protein in parasite lifecycle. Pf34 was refractory to attempted genetic modification. Antibodies to Pf34 abrogated the interaction and had a modest effect upon sporozoite invasion into primary human hepatocytes. Conclusion: Pf34 and PfRON6 may be members of a functionally important invasion complex which could be a target for future interventions. The modified interaction screening assay, protein expression libraries and P. falciparum mutant parasites reported here may be a useful tool for protein interaction discovery and antigen candidate screening which could be of wider value to the scientific community
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The AViKA (Adding Value in Knee Arthroplasty) postoperative care navigation trial: rationale and design features
Background: Utilization of total knee arthroplasty is increasing rapidly. A substantial number of total knee arthroplasty recipients have persistent pain after surgery. Our objective was to design a randomized controlled trial to establish the efficacy of a motivational-interviewing-based telephone intervention aimed at improving patient outcomes and satisfaction following total knee arthroplasty. Methods/Design The study was conducted at Brigham and Women’s Hospital in Boston, Massachusetts. The study focused on individuals 40 years or older with a primary diagnosis of osteoarthritis who were scheduled for total knee arthroplasty. The study compared two management strategies over the first six months postoperatively: 1) enhanced postoperative care with frequent follow-up by a care navigator; 2) usual postoperative care. Those who were randomized into the enhanced postoperative care arm received ten calls from a trained non-clinician care navigator over the first six postoperative months. The navigator used motivational interviewing techniques to engage patients in discussions related to their rehabilitation goals, including patient’s plans for and confidence in achieving those goals. Patients in the usual care arm received standard postoperative management and received no navigator phone calls. Patients in both arms were assessed at baseline, three months, and six months postoperatively. Discussion The primary outcome of the study was improvement in function as measured by the difference in Western Ontario and McMaster Universities Osteoarthritis Index function score between preoperative (baseline) status and six months postoperatively. Data were collected to identify factors that may be related to total knee arthroplasty outcomes, including preoperative pain, pain catastrophizing, self-efficacy, and depression. A formal economic analysis is also planned to determine the cost-effectiveness of the care navigator as a component of total knee arthroplasty care. Trial registration ClinicalTrials.gov NCT0154085
British Lung Foundation/United Kingdom primary immunodeficiency network consensus statement on the definition, diagnosis, and management of granulomatous-lymphocytic interstitial lung disease in common variable immunodeficiency disorders
A proportion of people living with common variable immunodeficiency disorders develop granulomatous-lymphocytic interstitial lung disease (GLILD). We aimed to develop a consensus statement on the definition, diagnosis, and management of GLILD. All UK specialist centers were contacted and relevant physicians were invited to take part in a 3-round online Delphi process. Responses were graded as Strongly Agree, Tend to Agree, Neither Agree nor Disagree, Tend to Disagree, and Strongly Disagree, scored +1, +0.5, 0, −0.5, and −1, respectively. Agreement was defined as greater than or equal to 80% consensus. Scores are reported as mean ± SD. There was 100% agreement (score, 0.92 ± 0.19) for the following definition: “GLILD is a distinct clinico-radio-pathological ILD occurring in patients with [common variable immunodeficiency disorders], associated with a lymphocytic infiltrate and/or granuloma in the lung, and in whom other conditions have been considered and where possible excluded.” There was consensus that the workup of suspected GLILD requires chest computed tomography (CT) (0.98 ± 0.01), lung function tests (eg, gas transfer, 0.94 ± 0.17), bronchoscopy to exclude infection (0.63 ± 0.50), and lung biopsy (0.58 ± 0.40). There was no consensus on whether expectant management following optimization of immunoglobulin therapy was acceptable: 67% agreed, 25% disagreed, score 0.38 ± 0.59; 90% agreed that when treatment was required, first-line treatment should be with corticosteroids alone (score, 0.55 ± 0.51)
Functional comparison of blood-stage Plasmodium falciparum malaria vaccine candidate antigens
The malaria genome encodes over 5,000 proteins and many of these have also been proposed to be potential vaccine candidates, although few of these have been tested clinically. RH5 is one of the leading blood-stage Plasmodium falciparum malaria vaccine antigens and Phase I/II clinical trials of vaccines containing this antigen are currently underway. Its likely mechanism of action is to elicit antibodies that can neutralize merozoites by blocking their invasion of red blood cells (RBC). However, many other antigens could also elicit neutralizing antibodies against the merozoite, and most of these have never been compared directly to RH5. The objective of this study was to compare a range of blood-stage antigens to RH5, to identify any antigens that outperform or synergize with anti-RH5 antibodies. We selected 55 gene products, covering 15 candidate antigens that have been described in the literature and 40 genes selected on the basis of bioinformatics functional prediction. We were able to make 20 protein-in-adjuvant vaccines from the original selection. Of these, S-antigen and CyRPA robustly elicited antibodies with neutralizing properties. Anti-CyRPA IgG generally showed additive GIA with anti-RH5 IgG, although high levels of anti-CyRPA-specific rabbit polyclonal IgG were required to achieve 50% GIA. Our data suggest that further vaccine antigen screening efforts are required to identify a second merozoite target with similar antibody-susceptibility to RH5
Parent-of-origin-specific allelic associations among 106 genomic loci for age at menarche.
Age at menarche is a marker of timing of puberty in females. It varies widely between individuals, is a heritable trait and is associated with risks for obesity, type 2 diabetes, cardiovascular disease, breast cancer and all-cause mortality. Studies of rare human disorders of puberty and animal models point to a complex hypothalamic-pituitary-hormonal regulation, but the mechanisms that determine pubertal timing and underlie its links to disease risk remain unclear. Here, using genome-wide and custom-genotyping arrays in up to 182,416 women of European descent from 57 studies, we found robust evidence (P < 5 × 10(-8)) for 123 signals at 106 genomic loci associated with age at menarche. Many loci were associated with other pubertal traits in both sexes, and there was substantial overlap with genes implicated in body mass index and various diseases, including rare disorders of puberty. Menarche signals were enriched in imprinted regions, with three loci (DLK1-WDR25, MKRN3-MAGEL2 and KCNK9) demonstrating parent-of-origin-specific associations concordant with known parental expression patterns. Pathway analyses implicated nuclear hormone receptors, particularly retinoic acid and γ-aminobutyric acid-B2 receptor signalling, among novel mechanisms that regulate pubertal timing in humans. Our findings suggest a genetic architecture involving at least hundreds of common variants in the coordinated timing of the pubertal transition
Extended self-knowledge
We aim to move the externalism and self-knowledge debate forward by exploring two novel sceptical challenges to the prospects of self-knowledge of a paradigmatic sort, both of which result from ways in which our thought content, cognitive processes and cognitive successes depend crucially on our external environments. In particular, it is shown how arguments from extended cognition (e.g., Clark A, Chalmers D. Analysis 58:7–19 (1998); Clark A. Supersizing the mind: Embodiment, action, and cognitive extension. Oxford: Oxford University Press (2008)) and situationism (e.g., Alfano M. The Philosophical Quarterly 62:223–249 (2012), Alfano M. Expanding the situationist challenge to reliabilism about inference. In Fairweather A (ed) Virtue epistemology naturalized, Springer, Dordrecht, pp 103–122 (2014); Doris JM. Noûs 32:504–530 (1998), Doris JM. Lack of character: Personality and moral behavior. Cambridge University Press, Cambridge (2002); Harman G. Proceedings of the Aristotelian Society. 99:315–331 (1999), Harman G. Proceedings of the Aristotelian Society 100:223–226 (2000)) pose hitherto unexplored challenges to the prospects of self-knowledge as it is traditionally conceived. It is shown, however, that, suitably understood, these apparent challenges in fact only demonstrate two ways in which our cognitive lives can be dependent on our environment. As such, rather than undermining our prospects for attaining self-knowledge, they instead illustrate how self-knowledge can be extended and expanded
Human Antibodies that Slow Erythrocyte Invasion Potentiate Malaria-Neutralizing Antibodies.
The Plasmodium falciparum reticulocyte-binding protein homolog 5 (PfRH5) is the leading target for next-generation vaccines against the disease-causing blood-stage of malaria. However, little is known about how human antibodies confer functional immunity against this antigen. We isolated a panel of human monoclonal antibodies (mAbs) against PfRH5 from peripheral blood B cells from vaccinees in the first clinical trial of a PfRH5-based vaccine. We identified a subset of mAbs with neutralizing activity that bind to three distinct sites and another subset of mAbs that are non-functional, or even antagonistic to neutralizing antibodies. We also identify the epitope of a novel group of non-neutralizing antibodies that significantly reduce the speed of red blood cell invasion by the merozoite, thereby potentiating the effect of all neutralizing PfRH5 antibodies as well as synergizing with antibodies targeting other malaria invasion proteins. Our results provide a roadmap for structure-guided vaccine development to maximize antibody efficacy against blood-stage malaria. Copyright © 2019 The Author(s). Published by Elsevier Inc. All rights reserved
The AViKA (Adding Value in Knee Arthroplasty) postoperative care navigation trial: rationale and design features
Analysis of the diverse antigenic landscape of the malaria protein RH5 identifies a potent vaccine-induced human public antibody clonotype
The highly conserved and essential Plasmodium falciparum reticulocyte-binding protein homolog 5 (PfRH5) has emerged as the leading target for vaccines against the disease-causing blood stage of malaria. However, the features of the human vaccine-induced antibody response that confer highly potent inhibition of malaria parasite invasion into red blood cells are not well defined. Here, we characterize 236 human IgG monoclonal antibodies, derived from 15 donors, induced by the most advanced PfRH5 vaccine. We define the antigenic landscape of this molecule and establish that epitope specificity, antibody association rate, and intra-PfRH5 antibody interactions are key determinants of functional anti-parasitic potency. In addition, we identify a germline IgG gene combination that results in an exceptionally potent class of antibody and demonstrate its prophylactic potential to protect against P. falciparum parasite challenge in vivo. This comprehensive dataset provides a framework to guide rational design of next-generation vaccines and prophylactic antibodies to protect against blood-stage malaria
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