11 research outputs found

    Roquin Paralogs 1 and 2 Redundantly Repress the Icos and Ox40 Costimulator mRNAs and Control Follicular Helper T Cell Differentiation

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    SummaryThe Roquin-1 protein binds to messenger RNAs (mRNAs) and regulates gene expression posttranscriptionally. A single point mutation in Roquin-1, but not gene ablation, increases follicular helper T (Tfh) cell numbers and causes lupus-like autoimmune disease in mice. In T cells, we did not identify a unique role for the much lower expressed paralog Roquin-2. However, combined ablation of both genes induced accumulation of T cells with an effector and follicular helper phenotype. We showed that Roquin-1 and Roquin-2 proteins redundantly repressed the mRNA of inducible costimulator (Icos) and identified the Ox40 costimulatory receptor as another shared mRNA target. Combined acute deletion increased Ox40 signaling, as well as Irf4 expression, and imposed Tfh differentiation on CD4+ T cells. These data imply that both proteins maintain tolerance by preventing inappropriate T cell activation and Tfh cell differentiation, and that Roquin-2 compensates in the absence of Roquin-1, but not in the presence of its mutated form

    Robust estimation of bacterial cell count from optical density

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    Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data

    Redesigning the market for volunteers: A donor registry

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    This paper addresses volunteer labor markets where the lack of price signals, nonpecuniary motivations to supply labor, and limited fungibility of supply lead to market failure. To address the causes of the market failure, we conduct a field experiment with volunteer whole blood donors where we introduce a market-clearing mechanism (henceforth: the Registry). Our intention-to-treat estimates suggest that subjects invited to the Registry, regardless of joining, are 66% more responsive to critical shortage appeals than control subjects. While the Registry increases supply during a critical shortage episode, it does not increase supply when there is no shortage; thus, the Registry significantly improves coordination between volunteer donors and collection centers, thereby improving market outcomes. We find evidence that the Registry’s effectiveness stems from crowding-in volunteers with purely altruistic motives and volunteers with a preference for commitment

    Reinduction therapy with everolimus in combination with dexamethasone, high-dose cytarabin and cisplatinum in patients with relapsed or refractory classical Hodgkin lymphoma: an experimental phase I/II multicentre trial of the German Hodgkin Study Group (GHSG HD-R3i)

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    Reinduction chemotherapy followed by high-dose chemotherapy and autologous stem cell transplant (HDCT + ASCT) is second-line standard of care for transplant-eligible patients with relapsed/refractory classical Hodgkin lymphoma (r/r cHL) but has a high failure rate. Because response to reinduction is predictive of the outcome after HDCT + ASCT, we aimed to improve the standard dexamethasone, high-dose cytarabine and cisplatinum (DHAP) reinduction regimen by addition of the oral mammalian target of rapamycin inhibitor everolimus (everDHAP). Transplant-eligible patients aged 18-60 years with histologically confirmed r/r cHL were included in this experimental phase I/II trial. Everolimus (10 mg/day, determined in phase-I-part) was administered on day 0-13 of each DHAP cycle. From July 2014 to March 2018, 50 patients were recruited to the phase II everDHAP group; two were not evaluable, three discontinued due to toxicity. Randomization to a placebo group stopped in October 2015 due to poor recruitment after nine patients. The primary end-point of computed tomography (CT)-based complete remission (CR) after two cycles of everDHAP was expected to be >= 40%. With a CT-based CR rate of 27% (n = 12/45) after two cycles of everDHAP the trial did not meet the primary end-point. Adding everolimus to DHAP is thus feasible; however, the everDHAP regimen failed to show an improved efficacy

    Pimozide Augmentation of Clozapine Inpatients with Schizophrenia and Schizoaffective Disorder Unresponsive to Clozapine Monotherapy

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    Despite its superior efficacy, clozapine is helpful in only a subset of patients with schizophrenia unresponsive to other antipsychotics. This lack of complete success has prompted the frequent use of various clozapine combination strategies despite a paucity of evidence from randomized controlled trials supporting their efficacy. Pimozide, a diphenylbutylpiperidine, possesses pharmacological and clinical properties distinct from other typical antipsychotics. An open-label trial of pimozide adjunctive treatment to clozapine provided promising pilot data in support of a larger controlled trial. Therefore, we conducted a double-blind, placebo-controlled, parallel-designed 12-week trial of pimozide adjunctive treatment added to ongoing optimal clozapine treatment in 53 patients with schizophrenia and schizoaffective disorder partially or completely unresponsive to clozapine monotherapy. An average dose of 6.48 mg/day of pimozide was found to be no better than placebo in combination with clozapine at reducing Positive and Negative Syndrome Scale total, positive, negative, and general psychopathology scores. There is no suggestion from this rigorously conducted trial to suggest that pimozide is an effective augmenting agent if an optimal clozapine trial is ineffective. However, given the lack of evidence to guide clinicians and patients when clozapine does not work well, more controlled trials of innovative strategies are warranted

    Evolution of genes and genomes on the Drosophila phylogeny

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    Comparative analysis of multiple genomes in a phylogenetic framework dramatically improves the precision and sensitivity of evolutionary inference, producing more robust results than single-genome analyses can provide. The genomes of 12 Drosophila species, ten of which are presented here for the first time (sechellia, simulans, yakuba, erecta, ananassae, persimilis, willistoni, mojavensis, virilis and grimshawi), illustrate how rates and patterns of sequence divergence across taxa can illuminate evolutionary processes on a genomic scale. These genome sequences augment the formidable genetic tools that have made Drosophila melanogaster a pre-eminent model for animal genetics, and will further catalyse fundamental research on mechanisms of development, cell biology, genetics, disease, neurobiology, behaviour, physiology and evolution. Despite remarkable similarities among these Drosophila species, we identified many putatively non-neutral changes in protein-coding genes, non-coding RNA genes, and cis-regulatory regions. These may prove to underlie differences in the ecology and behaviour of these diverse species
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