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Herein, we explore the generation and characterization of the radical cations of glycylphenylalanylglycine, or [GFG]•+, formed via dissociative electron-transfer reaction from the tripeptide to copper(II) within a ternary complex. A comprehensive investigation employing isotopic labeling, infrared multiple-photon dissociation (IRMPD) spectroscopy, and density functional theory (DFT) calculations elucidated the details and energetics in formation of the peptide radical cations as well as their dissociation products. Unlike conventional aromatic-containing peptide radical cations that primarily form canonical π-radicals, our findings reveal that 75% of the population of the experimentally produced [GFG]•+ precursors are [GFα•G]+, where the radical resides on the middle α-carbon of the phenylalanyl residue. This unexpected isomeric ion has an enthalpy of 6.8 kcal/mol above the global minimum, which has an N-terminal captodative structure, [Gα•FG]+, comprising 25% of the population. The [b₂-H]•+ product ions are also present in a ratio of 75/25 from [GFα•G]+/ [Gα•FG]+, the results of which are obtained from matches between the IRMPD action spectrum and predicted IR absorption spectra of the [b₂-H]•+ candidate structures, as well as from IRMPD isomer population analyses., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2024 Li et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Sinorhizobium meliloti is a model alpha-proteobacterium for investigating microbe-host interactions, in particular nitrogen-fixing rhizobium-legume symbioses. Successful infection requires complex coordination between compatible host and endosymbiont, including bacterial production of succinoglycan, also known as exopolysaccharide-I (EPS-I). In S. meliloti EPS-I production is controlled by the conserved ExoS-ChvI two-component system. Periplasmic ExoR associates with the ExoS histidine kinase and negatively regulates ChvI-dependent expression of exo genes, necessary for EPS-I synthesis. We show that two extracytoplasmic proteins, LppA (a lipoprotein) and JspA (a lipoprotein and a metalloprotease), jointly influence EPS-I synthesis by modulating the ExoR-ExoS-ChvI pathway and expression of genes in the ChvI regulon. Deletions of jspA and lppA led to lower EPS-I production and competitive disadvantage during host colonization, for both S. meliloti with Medicago sativa and S. medicae with M. truncatula. Overexpression of jspA reduced steady-state levels of ExoR, suggesting that the JspA protease participates in ExoR degradation. This reduction in ExoR levels is dependent on LppA and can be replicated with ExoR, JspA, and LppA expressed exogenously in Caulobacter crescentus and Escherichia coli. Akin to signaling pathways that sense extracytoplasmic stress in other bacteria, JspA and LppA may monitor periplasmic conditions during interaction with the plant host to adjust accordingly expression of genes that contribute to efficient symbiosis. The molecular mechanisms underlying host colonization in our model system may have parallels in related alpha-proteobacteria., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2023 Bustamante et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Discordance between angiography-based anatomical assessment of coronary stenosis severity and fractional flow reserve (FFR) has been attributed to several factors including lesion length and irregularity, and the myocardial territory supplied by the target vessel. We sought to examine if coronary arterial distensibility is an independent contributor to this discordance. There were two parts to this study. The first consisted of "in silico" models of 26 human coronary arteries. Computational fluid dynamics-derived FFR was calculated for fully rigid, partially distensible and fully distensible models of the 26 arteries. The second part of the study consisted of 104 patients who underwent coronary angiography and FFR measurement. Distensibility at the lesion site (DistensibilityMLA) and for the reference vessel (DistensibilityRef) was determined by analysing three-dimensional angiography images during end-systole and end-diastole. Computational fluid dynamics-derived FFR was 0.67±0.19, 0.70±0.18 and 0.75±0.17 (P<0.001) in the fully rigid, partially distensible and fully distensible models respectively. FFR correlated with both DistensibilityMLA (r = 0.36, P<0.001) and DistensibilityRef (r = 0.44, P<0.001). Two-way ANCOVA analysis revealed that DistensibilityMLA (F (1, 100) = 4.17, p = 0.031) and percentage diameter stenosis (F (1, 100) = 60.30, p < 0.01) were both independent predictors of FFR. Coronary arterial distensibility is a novel, independent determinant of FFR, and an important factor contributing to the discordance between anatomical and functional assessment of stenosis severity.

Background: Pulmonary embolism continues to be a significant cause of death. The aim was to derive and validate a risk prediction model for in-hospital death after acute pulmonary embolism to identify low risk patients suitable for outpatient management., Methods: A confirmed acute pulmonary embolism database of 1,426 consecutive patients admitted to a tertiary-center (2000-2012) was analyzed, with odd and even years as derivation and validation cohorts respectively. Risk stratification for in-hospital death was performed using multivariable logistic-regression modelling. Models were compared using receiver-operating characteristic-curve and decision curve analyses., Results: In-hospital mortality was 3.6% in the derivation cohort (n = 693). Adding day-1 sodium and bicarbonate to simplified Pulmonary Embolism Severity Index (sPESI) significantly increased the C-statistic for predicting in-hospital death (0.71 to 0.86, P = 0.001). The validation cohort yielded similar results (n = 733, C-statistic 0.85). The new model was associated with a net reclassification improvement of 0.613, and an integrated discrimination improvement of 0.067. The new model also increased the C-statistic for predicting 30-day mortality compared to sPESI alone (0.74 to 0.83, P = 0.002). Decision curve analysis demonstrated superior clinical benefit with the use of the new model to guide admission for pulmonary embolism, resulting in 43 fewer admissions per 100 presentations based on a risk threshold for admission of 2%., Conclusions: A risk model incorporating sodium, bicarbonate, and the sPESI provides accurate risk prediction of acute in-hospital mortality after pulmonary embolism. Our novel model identifies patients with pulmonary embolism who are at low risk and who may be suitable for outpatient management.

Background: Acute pulmonary embolism (PE) carries an increased risk of death. Using transthoracic echocardiography (TTE) to assist diagnosis and risk stratification is recommended in current guidelines. However, its utilization in real-world clinical practice is unknown. We conducted a retrospective observational study to delineate the prevalence of inpatient TTE use following confirmed acute PE, identify predictors for its use and its impact on patient's outcome., Methods: Clinical details of consecutive patients (2000 to 2012) from two tertiary-referral hospitals were retrieved from dedicated PE databases. All-cause and cause-specific mortality was tracked from a state-wide death registry., Results: In total, 2306 patients were admitted with confirmed PE, of whom 687 (29.8%) had inpatient TTE (39.3% vs 14.4% between sites, P<0.001). Site to which patient presented, older age, cardiac failure, atrial fibrillation and diabetes were independent predictors for inpatient TTE use, while malignancy was a negative predictor. Overall mortality was 41.4% (mean follow-up 66.5±49.5months). Though inpatient TTE use was not an independent predictor for all-cause or cardiovascular mortality in multivariable analysis, in the inpatient TTE subgroup, right ventricle-right atrial pressure gradient (hazard ratio [HR] 1.02 per-1mmHg increase, 95% confidence interval [CI] 1.01-1.03) and moderate/severe aortic stenosis (HR 2.26, 95% CI 1.20-4.27) independently predicted all-cause mortality., Conclusions: Inpatient TTE is used infrequently in real-world clinical settings following acute PE despite its usefulness in risk stratification, prognostication and assessing comorbid cardiac pathologies. Identifying patients that will benefit most from a TTE assessment following an acute PE episode and reducing barriers in accessing TTE should be explored., Competing Interests: The authors have declared that no competing interests exist.

Background: Symptomatic pulmonary embolism (PE) is a major cause of cardiovascular death and morbidity. Estimated prevalence and incidence of atrial fibrillation (AF) in developed countries are between 388-661 per 100,000, and 90-123 per 100,000 person-years respectively. However, the prevalence and incidence of AF in patients presenting with an acute PE and its predictors are not clear., Methods: Individual patient clinical details were retrieved from a database containing all confirmed acute PE presentations to a tertiary institution from 2001-2012. Prevalence and incidence of AF was tracked from a population registry by systematically searching for AF during any hospital admission (2000-2013) based on International Classification of Disease (ICD-10) code., Results: Of the 1,142 patients included in this study, 935 (81.9%) had no AF during index PE admission whilst 207 patients had documented baseline AF (prevalence rate 18,126 per 100,000; age-adjusted 4,672 per 100,000). Of the 935 patients without AF, 126 developed AF post-PE (incidence rate 2,778 per 100,000 person-years; age-adjusted 984 per 100,000 person-years). Mean time from PE to subsequent AF was 3.4 ± 2.9 years. Total mortality (mean follow-up 5.0 ± 3.7 years) was 42% (n = 478): 35% (n = 283), 59% (n = 119) and 60% (n = 76) in the no AF, baseline AF and subsequent AF cohorts respectively. Independent predictors for subsequent AF after acute PE include age (hazard ratio [HR] 1.06, 95% confidence interval [CI] 1.04-1.08, p<0.001), history of congestive cardiac failure (HR 1.88, 95% CI 1.12-3.16, p = 0.02), diabetes (HR 1.72, 95% CI 1.07-2.77, p = 0.02), obstructive sleep apnea (HR 4.83, 1.48-15.8, p = 0.009) and day-1 serum sodium level during index PE admission (HR 0.94, 95% CI 0.90-0.98, p = 0.002)., Conclusions: Patients presenting with acute PE have a markedly increased age-adjusted prevalence and subsequent incidence of AF. Screening for AF may be of importance post-PE.

We contrasted the neuroanatomical substrates of sub-acute and chronic visuospatial deficits associated with different aspects of unilateral neglect using computed tomography scans acquired as part of routine clinical diagnosis. Voxel-wise statistical analyses were conducted on a group of 160 stroke patients scanned at a sub-acute stage. Lesion-deficit relationships were assessed across the whole brain, separately for grey and white matter. We assessed lesions that were associated with behavioural performance (i) at a sub-acute stage (within 3 months of the stroke) and (ii) at a chronic stage (after 9 months post stroke). Allocentric and egocentric neglect symptoms at the sub-acute stage were associated with lesions to dissociated regions within the frontal lobe, amongst other regions. However the frontal lesions were not associated with neglect at the chronic stage. On the other hand, lesions in the angular gyrus were associated with persistent allocentric neglect. In contrast, lesions within the superior temporal gyrus extending into the supramarginal gyrus, as well as lesions within the basal ganglia and insula, were associated with persistent egocentric neglect. Damage within the temporo-parietal junction was associated with both types of neglect at the sub-acute stage and 9 months later. Furthermore, white matter disconnections resulting from damage along the superior longitudinal fasciculus were associated with both types of neglect and critically related to both sub-acute and chronic deficits. Finally, there was a significant difference in the lesion volume between patients who recovered from neglect and patients with chronic deficits. The findings presented provide evidence that (i) the lesion location and lesion size can be used to successfully predict the outcome of neglect based on clinical CT scans, (ii) lesion location alone can serve as a critical predictor for persistent neglect symptoms, (iii) wide spread lesions are associated with neglect symptoms at the sub-acute stage but only some of these are critical for predicting whether neglect will become a chronic disorder and (iv) the severity of behavioural symptoms can be a useful predictor of recovery in the absence of neuroimaging findings on clinical scans. We discuss the implications for understanding the symptoms of the neglect syndrome, the recovery of function and the use of clinical scans to predict outcome.

Background: Small cell lung cancer (SCLC) is characterized by rapid progression and low survival rates. Therefore, novel therapeutic agents are urgently needed for this disease. Capsaicin, the active ingredient of chilli peppers, displays anti-proliferative activity in prostate and epidermoid cancer in vitro. However, the anti-proliferative activity of capsaicin has not been studied in human SCLCs. The present manuscript fills this void of knowledge and explores the anti-proliferative effect of capsaicin in SCLC in vitro and in vivo., Methodology/principal Findings: BrdU assays and PCNA ELISAs showed that capsaicin displays robust anti-proliferative activity in four human SCLC cell lines. Furthermore, capsaicin potently suppressed the growth of H69 human SCLC tumors in vivo as ascertained by CAM assays and nude mice models. The second part of our study attempted to provide insight into molecular mechanisms underlying the anti-proliferative activity of capsaicin. We found that the anti-proliferative activity of capsaicin is correlated with a decrease in the expression of E2F-responsive proliferative genes like cyclin E, thymidylate synthase, cdc25A and cdc6, both at mRNA and protein levels. The transcription factor E2F4 mediated the anti-proliferative activity of capsaicin. Ablation of E2F4 levels by siRNA methodology suppressed capsaicin-induced G1 arrest. ChIP assays demonstrated that capsaicin caused the recruitment of E2F4 and p130 on E2F-responsive proliferative promoters, thereby inhibiting cell proliferation., Conclusions/significance: Our findings suggest that the anti-proliferative effects of capsaicin could be useful in the therapy of human SCLCs.