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NMR-assisted crystallography-the integrated application of solid-state NMR, X-ray crystallography, and first-principles computational chemistry-holds significant promise for mechanistic enzymology by providing atomic-resolution characterization of stable intermediates in enzyme active sites, including hydrogen atom locations and tautomeric equilibria, NMR crystallography offers insight into both structure and chemical dynamics. Here, this integrated approach is used to characterize the tryptophan synthase α-aminoacrylate intermediate, a defining species for pyridoxal-5'-phosphate-dependent enzymes that catalyze β-elimination and replacement reactions. For this intermediate, NMR-assisted crystallography is able to identify the protonation states of the ionizable sites on the cofactor, substrate, and catalytic side chains as well as the location and orientation of crystallographic waters within the active site. Most notable is the water molecule immediately adjacent to the substrate β-carbon, which serves as a hydrogen bond donor to the ε-amino group of the acid-base catalytic residue βLys87. From this analysis, a detailed three-dimensional picture of structure and reactivity emerges, highlighting the fate of the L-serine hydroxyl leaving group and the reaction pathway back to the preceding transition state. Reaction of the α-aminoacrylate intermediate with benzimidazole, an isostere of the natural substrate indole, shows benzimidazole bound in the active site and poised for, but unable to initiate, the subsequent bond formation step. selleck products When modeled into the benzimidazole position, indole is positioned with C3 in contact with the α-aminoacrylate Cβ and aligned for nucleophilic attack. Here, the chemically detailed, three-dimensional structure from NMR-assisted crystallography is key to understanding why benzimidazole does not react, while indole does.Lipoprotein-associated phospholipase A2 (Lp-PLA2) associates with low- and high-density lipoproteins in human plasma and specifically hydrolyzes circulating oxidized phospholipids involved in oxidative stress. link2 The association of this enzyme with the lipoprotein's phospholipid monolayer to access its substrate is the most crucial first step in its catalytic cycle. The current study demonstrates unequivocally that a significant movement of a major helical peptide region occurs upon membrane binding, resulting in a large conformational change upon Lp-PLA2 binding to a phospholipid surface. This allosteric regulation of an enzyme's activity by a large membrane-like interface inducing a conformational change in the catalytic site defines a unique dimension of allosterism. The mechanism by which this enzyme associates with phospholipid interfaces to select and extract a single phospholipid substrate molecule and carry out catalysis is key to understanding its physiological functioning. A lipidomics platform was employed to determine the precise substrate specificity of human recombinant Lp-PLA2 and mutants. This study uniquely elucidates the association mechanism of this enzyme with membranes and its resulting conformational change as well as the extraction and binding of specific oxidized and short acyl-chain phospholipid substrates. Deuterium exchange mass spectrometry coupled with molecular dynamics simulations was used to define the precise specificity of the subsite for the oxidized fatty acid at the sn-2 position of the phospholipid backbone. Despite the existence of several crystal structures of this enzyme cocrystallized with inhibitors, little was understood about Lp-PLA2's specificity toward oxidized phospholipids.Invariant stimulus recognition is a challenging pattern-recognition problem that must be dealt with by all sensory systems. Since neural responses evoked by a stimulus are perturbed in a multitude of ways, how can this computational capability be achieved? We examine this issue in the locust olfactory system. We find that locusts trained in an appetitive-conditioning assay robustly recognize the trained odorant independent of variations in stimulus durations, dynamics, or history, or changes in background and ambient conditions. However, individual- and population-level neural responses vary unpredictably with many of these variations. Our results indicate that linear statistical decoding schemes, which assign positive weights to ON neurons and negative weights to OFF neurons, resolve this apparent confound between neural variability and behavioral stability. Furthermore, simplification of the decoder using only ternary weights (+1, 0, -1) (i.e., an "ON-minus-OFF" approach) does not compromise performance, thereby striking a fine balance between simplicity and robustness.This brief report presents the global problem of the shortfall of donor corneal tissue for transplantation, a potential root cause ('ick factor' language), and a potential solution (modification of 'ick factor' language). Specifically, use of the term 'eye donation' is a potential hurdle to ocular tissue donation as it can stimulate the 'ick factor.' Verbiage such as 'ocular (eye tissue)' could be a method of providing terminology that is less emotive than 'eye donor' or 'eye donation.' The field of transplantation has experienced terminology shifts over time; for example, 'cadaver' has been replaced with 'deceased donor,' 'harvest' has been replaced with 'recover,' and 'life support' has been replaced with 'ventilated.' Notably, only a small number of regions worldwide are using 'ocular' terminology, yet it could be an important step to enhancing the informed consent process and improving donation rates, potentially increasing transplant and optimising patient quality of life for those with treatable blindness.

To systematically code and classify longitudinal cigarette consumption trajectories in European countries since 1970.

Blinded duplicate qualitative coding of periods of year-over-year relative increase, plateau, and decrease of national per capita cigarette consumption and categorisation of historical cigarette consumption trajectories based on longitudinal patterns emerging from the data.

41 countries or former countries in the European region for which data are available between 1970 and 2015.

Regional trends in longitudinal consumption patterns identify stable or decreasing consumption throughout Northern, Western and Southern European countries, while Eastern and Southeastern European countries experienced much greater instability. The 11 emergent classes of historical cigarette consumption trajectories were also regionally clustered, including a distinctive inverted U or sine wave pattern repeatedly emerging from former Soviet and Southeastern European countries.

The open-access data produced bionally clustered historical trajectories of cigarette consumption in Europe suggest that the enduring normative frame of a gently sloping downward curve in cigarette consumption can offer a false sense of security among policymakers and can distract from plausible causal mechanisms among researchers. These multilevel and multisectoral causal mechanisms point to the need for a greater understanding of the political economy of regional and global determinants of cigarette consumption.

Glucocorticoids (GC) withdrawal is part of the targets in current recommendations for SLE, but relapse is the most worrying issue. We aimed to investigate the predictors for flare in patients with SLE after GC withdrawal.

We systematically searched PubMed, EMBASE and Cochrane Library as well as Scopus databases up to 9 July 2021 for studies concerning predictive factors of relapses in patients with SLE after GC cessation. Pooled OR and 95% CI were combined using a random-effects or fixed-effects model.

635 patients with SLE with GC discontinuation in 9 publications were eligible for the final analysis. Of them, 99.5% patients were in clinical remission before GC withdrawal. Serologically active yet clinically quiescent (SACQ) was associated with an increased risk of flare after GC withdrawal (OR 1.78, 95% CI (1.00 to 3.15)). Older age and concomitant use of hydroxychloroquine (HCQ) trended towards decreased risk of flare (weighted mean difference (WMD) -2.04, 95% CI (-4.15 to 0.06) for age and OR 0.50, 95% CI (0.23 to 1.07) for HCQ), yet not statistically significant. No significant association was observed regarding gender (pooled OR 1.75; 95% CI (0.59 to 5.20)), disease duration (WMD -11.91, 95% CI (-27.73 to 3.91)), remission duration (WMD -8.55, 95% CI (-33.33 to 16.23)), GC treatment duration (WMD -10.10, 95% CI (-64.09 to 43.88)), concomitant use of immunosuppressant (OR 0.86, 95% CI (0.48 to 1.53)).

Younger age and SACQ were potential risk factors of SLE flare among patients who discontinued GC. HCQ, but not immunosuppressant might prevent flare. GC withdrawal should be done with caution in this subgroup of patients.

Younger age and SACQ were potential risk factors of SLE flare among patients who discontinued GC. HCQ, but not immunosuppressant might prevent flare. GC withdrawal should be done with caution in this subgroup of patients.

Evaluate the impact of pregnancy physiology and medication non-adherence on serum hydroxychloroquine (HCQ) pharmacokinetics (PK) and exposure-response in SLE.

We conducted a PK analysis using data from two observational pregnancy registries. We enrolled pregnant women with SLE taking HCQ at least 3 months prior to, and throughout pregnancy, and excluded those with multiple gestations. Using the PK model, we conducted dosing simulations and imputed 0%/20%/40%/60% non-adherence to evaluate the impact of adherence versus physiological changes on HCQ concentrations. link3 We compared the effect of pregnancy-average non-adherent concentrations (≤100 ng/mL vs >100 ng/mL) on preterm birth using adjusted logistic regression.

We enrolled 56 women who had 61 pregnancies. By the third trimester, mean apparent HCQ clearance increased by 59.6%. At a dosage of 400 mg/day, fully adherent patients are expected to have HCQ concentrations ≤100 ng/mL only 0.3% of the time, compared with 24.2% when 60% of doses are missed. Peion non-adherence had a more pronounced effect on HCQ exposure compared with physiological changes alone. Moreover, pregnant women with non-adherent HCQ concentrations had significantly higher rates of preterm birth. Accordingly, optimising adherence in pregnancy may be more clinically meaningful than adjusting HCQ dosage to account for physiological changes. PK modelling indicates that serum HCQ concentrations ≤100 ng/mL are suggestive of non-adherence regardless of trimester and may help identify pregnancies at risk for poor outcomes.

Treatment failures for lupus nephritis (LN) are high with 10%-30% of patients progressing to end-stage renal disease (ESRD) within 10 years. Interstitial fibrosis/tubular atrophy (IFTA) is a predictor of progression to ESRD. Prior studies suggest that tubulointerstitial injury secondary to proteinuria in LN is mediated by complement activation in the tubules, specifically through the membrane attack complex (MAC). This study aimed to investigate the associations between tubular MAC deposition with IFTA and proteinuria.

In this cross-sectional study, LN kidney biopsies were assessed for MAC deposition by staining for Complement C9, a component of the MAC. Chromogenic immunohistochemistry was performed on paraffin-embedded human renal biopsy sections using unconjugated, murine anti-human Complement C9 (Hycult Biotech, clone X197). Tubular C9 staining intensity was analysed as present versus absent. IFTA was defined as minimal (<10%), mild (10%-24%), moderate (25%-50%) and severe (>50%).

Renal biopsies from 30 patients with LN were studied.