The Dynamic Structure of Thrombin in Solution

AbstractThe backbone dynamics of human α-thrombin inhibited at the active site serine were analyzed using R1, R2, and heteronuclear NOE experiments, variable temperature TROSY 2D [1H-15N] correlation spectra, and Rex measurements. The N-terminus of the heavy chain, which is formed upon zymogen activation and inserts into the protein core, is highly ordered, as is much of the double beta-barrel core. Some of the surface loops, by contrast, remain very dynamic with order parameters as low as 0.5 indicating significant motions on the ps-ns timescale. Regions of the protein that were thought to be dynamic in the zymogen and to become rigid upon activation, in particular the γ-loop, the 180s loop, and the Na+ binding site have order parameters below 0.8. Significant Rex was observed in most of the γ-loop, in regions proximal to the light chain, and in the β-sheet core. Accelerated molecular dynamics simulations yielded a molecular ensemble consistent with measured residual dipolar couplings that revealed dynamic motions up to milliseconds. Several regions, including the light chain and two proximal loops, did not appear highly dynamic on the ps-ns timescale, but had significant motions on slower timescales

Peripheral artery disease causes consistent gait irregularities regardless of the location of leg claudication pain

Highlights Peripheral artery disease (PAD) is a multi-level disease. PAD diffusely impairs the performance of leg muscles. PAD causes similar irregularities in gait biomechanics regardless of where claudication pain is located in the leg. Abstract Background The most common symptom of peripheral artery disease (PAD) is intermittent claudication that involves the calf, thigh, and/or buttock muscles. How the specific location of this leg pain is related to altered gait, however, is unknown. Objectives We hypothesized that because the location of claudication symptoms uniquely affects different leg muscle groups in people with PAD, this would produce distinctive walking patterns. Methods A total of 105 participants with PAD and 35 age-matched older volunteers without PAD (CTRL) were recruited. Participants completed walking impairment questionnaires (WIQ), Gardner-Skinner progressive treadmill tests, the six-minute walk test, and we performed an advanced evaluation of the biomechanics of their overground walking. Participants with PAD were categorized into 4 groups according to their stated pain location(s): calf only (C, n = 43); thigh and calf (TC, n = 18); buttock and calf (BC, n = 15); or buttock, thigh, and calf (BTC, n = 29). Outcomes were compared between CTRL, C, TC, BC and BTC groups using a one-way ANOVA with post-hoc comparisons to identify and assess statistically significant differences. Results There were no significant differences between CTRL, C, TC, BC and BTC groups in distances walked or walking speed when either pain-free or experiencing claudication pain. Each participant with PAD had significantly dysfunctional biomechanical gait parameters, even when pain-free, when compared to CTRL (pain-free) walking data. During pain-free walking, out of the 18 gait parameters evaluated, we only identified significant differences in hip power generation during push-off (in C and TC groups) and in knee power absorption during weight acceptance (in TC and BC groups). There were no between-group differences in gait parameters while people with PAD were walking with claudication pain. Conclusions Our data demonstrate that PAD affects the ischemic lower extremities in a diffuse manner irrespective of the location of claudication symptoms. Database Registration ClinicalTrials.gov NCT01970332

Fueling the flames of colon cancer – does CRP play a direct pro-inflammatory role?

Background: Systemic inflammation, diagnostically ascribed by measuring serum levels of the acute phase reactant C-reactive protein (CRP), has consistently been correlated with poor outcomes across cancer types. CRP exists in two structurally and functionally distinct isoforms, circulating pentameric CRP (pCRP) and the highly pro-inflammatory monomeric isoform (mCRP). The aim of this pilot study was to map the pattern of mCRP distribution in a previously immunologically well-defined colon cancer (CC) cohort and explore possible functional roles of mCRP within the tumor microenvironment (TME). Methods: Formalin-fixed, paraffin-embedded (FFPE) tissue samples from 43 stage II and III CC patients, including 20 patients with serum CRP 0-1 mg/L and 23 patients with serum CRP >30 mg/L were immunohistochemically (IHC) stained with a conformation-specific mCRP antibody and selected immune and stromal markers. A digital analysis algorithm was developed for evaluating mCRP distribution within the primary tumors and adjacent normal colon mucosa. Results: mCRP was abundantly present within tumors from patients with high serum CRP (>30 mg/L) diagnostically interpreted as being systemically inflamed, whereas patients with CRP 0-1 mg/L exhibited only modest mCRP positivity (median mCRP per area 5.07‰ (95%CI:1.32-6.85) vs. 0.02‰ (95%CI:0.01-0.04), p<0.001). Similarly, tissue-expressed mCRP correlated strongly with circulating pCRP (Spearman correlation 0.81, p<0.001). Importantly, mCRP was detected exclusively within tumors, whereas adjacent normal colon mucosa showed no mCRP expression. Double IHC staining revealed colocalization of mCRP with endothelial cells and neutrophils. Intriguingly, some tumor cells also colocalized with mCRP, suggesting a direct interaction or mCRP expression by the tumor itself. Conclusion: Our data show that the pro-inflammatory mCRP isoform is expressed in the TME of CC, primarily in patients with high systemic pCRP values. This strengthens the hypothesis that CRP might not only be an inflammatory marker but also an active mediator within tumors.publishedVersio

Choline supplementation in children with fetal alcohol spectrum disorders: a randomized, double-blind, placebo-controlled trial

Background: Fetal alcohol spectrum disorders (FASDs) are conditions characterized by physical anomalies, neurodevelopmental abnormalities, and neurocognitive deficits, including intellectual, executive, and memory deficits. There are no specific biological treatments for FASDs, but rodent models have shown that prenatal or postnatal choline supplementation reduces cognitive and behavioral deficits. Potential mechanisms include phospholipid production for axonal growth and myelination, acetylcholine enhancement, and epigenetic effects

When and how favour rendering ameliorates workplace ostracism over time: Moderating effect of self‐monitoring and mediating effect of popularity enhancement

Despite increasing scholarly attention to workplace ostracism, victims receive little guidance regarding how to break its negative spiral over time. Drawing on a multi‐motive model of rejection‐related experiences and the cybernetic model of impression management, this study examines how and why ostracized employees might ameliorate workplace ostracism through impression management efforts to enhance their popularity. Specifically, an ostracized worker may employ favour rendering tactics to enhance her or his popularity, as reported by peers, which can help reduce ostracism. In addition, ostracized employees with strong self‐monitoring tendencies may be more likely to employ favour rendering tactics and use them more effectively to enhance their popularity and thus reduce ostracism. Data collected from 277 employee–coworker pairs in a three‐wave, time‐lagged design over 2 years confirm the proposed hypotheses, tested in a two‐stage moderated mediation model. These findings have theoretical implications for ostracism research, as well as practical implications to help employees and organizations overcome ostracism

A multi-site collaborative study of the hostile priming effect

Data Accessibility Statement: See Table 1.Supplementary data: Peer Review History - docx file - available online at: https://online.ucpress.edu/collabra/article/7/1/18738/116070/A-Multi-Site-Collaborative-Study-of-the-Hostile#supplementary-data .In a now-classic study by Srull and Wyer (1979), people who were exposed to phrases with hostile content subsequently judged a man as being more hostile. And this “hostile priming effect” has had a significant influence on the field of social cognition over the subsequent decades. However, a recent multi-lab collaborative study (McCarthy et al., 2018) that closely followed the methods described by Srull and Wyer (1979) found a hostile priming effect that was nearly zero, which casts doubt on whether these methods reliably produce an effect. To address some limitations with McCarthy et al. (2018), the current multi-site collaborative study included data collected from 29 labs. Each lab conducted a close replication (total N = 2,123) and a conceptual replication (total N = 2,579) of Srull and Wyer’s methods. The hostile priming effect for both the close replication (d = 0.09, 95% CI [-0.04, 0.22], z = 1.34, p = .16) and the conceptual replication (d = 0.05, 95% CI [-0.04, 0.15], z = 1.15, p = .58) were not significantly different from zero and, if the true effects are non-zero, were smaller than what most labs could feasibly and routinely detect. Despite our best efforts to produce favorable conditions for the effect to emerge, we did not detect a hostile priming effect. We suggest that researchers should not invest more resources into trying to detect a hostile priming effect using methods like those described in Srull and Wyer (1979).We have no funding to declare for this project

A Multisite Preregistered Paradigmatic Test of the Ego-Depletion Effect

We conducted a preregistered multilaboratory project (k = 36; N = 3,531) to assess the size and robustness of ego-depletion effects using a novel replication method, termed the paradigmatic replication approach. Each laboratory implemented one of two procedures that was intended to manipulate self-control and tested performance on a subsequent measure of self-control. Confirmatory tests found a nonsignificant result (d = 0.06). Confirmatory Bayesian meta-analyses using an informed-prior hypothesis (δ = 0.30, SD = 0.15) found that the data were 4 times more likely under the null than the alternative hypothesis. Hence, preregistered analyses did not find evidence for a depletion effect. Exploratory analyses on the full sample (i.e., ignoring exclusion criteria) found a statistically significant effect (d = 0.08); Bayesian analyses showed that the data were about equally likely under the null and informed-prior hypotheses. Exploratory moderator tests suggested that the depletion effect was larger for participants who reported more fatigue but was not moderated by trait self-control, willpower beliefs, or action orientation.</p

A Multisite Preregistered Paradigmatic Test of the Ego-Depletion Effect

We conducted a preregistered multilaboratory project (k = 36; N = 3,531) to assess the size and robustness of ego-depletion effects using a novel replication method, termed the paradigmatic replication approach. Each laboratory implemented one of two procedures that was intended to manipulate self-control and tested performance on a subsequent measure of self-control. Confirmatory tests found a nonsignificant result (d = 0.06). Confirmatory Bayesian meta-analyses using an informed-prior hypothesis (δ = 0.30, SD = 0.15) found that the data were 4 times more likely under the null than the alternative hypothesis. Hence, preregistered analyses did not find evidence for a depletion effect. Exploratory analyses on the full sample (i.e., ignoring exclusion criteria) found a statistically significant effect (d = 0.08); Bayesian analyses showed that the data were about equally likely under the null and informed-prior hypotheses. Exploratory moderator tests suggested that the depletion effect was larger for participants who reported more fatigue but was not moderated by trait self-control, willpower beliefs, or action orientation