Effects of Implantable Cardioverter-Defibrillator Leads on the Tricuspid Valve and Right Ventricle: A Randomized Trial.

BACKGROUND: There are no randomized data to inform the extent to which transvenous cardiac leads cause tricuspid regurgitation (TR). OBJECTIVES: This study sought to determine the effect of a transvenous implantable cardioverter-defibrillator (TV-ICD) on TR severity, and secondarily, on right ventricular (RV) size and function. METHODS: We evaluated TR severity before and 6 months after implantable cardioverter-defibrillator insertion in a post hoc analysis of adults randomized to receive a transvenous (n = 252) or subcutaneous implantable cardioverter-defibrillator (S-ICD) (n = 251) device. TR and RV size and systolic function were assessed by echocardiographic images analyzed in a core laboratory. RESULTS: At baseline, at least mild TR was present in 30% of individuals. At 6 months, the proportion of participants with any TR in the TV-ICD group was 42% vs 19% in the S-ICD group (P < 0.001). The proportion with moderate or severe TR was 7% in the TV-ICD group vs 2% in the S-ICD group (P = 0.021). At 6 months, the OR of at least 1 grade worsening of TR in the TV-ICD group as compared with the S-ICD group was 7.2 (95% CI: 3.3-15.8; P < 0.001). There were no differences between groups with respect to RV size or systolic function. CONCLUSIONS: Six months following TV-ICD insertion, there was a 7-fold increase in the risk of at least 1 grade worsening of TR, with 7% of individuals having TR that was moderate or severe. There was no detectable difference in RV size or function; however, longer follow-up is needed.

Caging Bioactive Triarylimidazoles: An Approach to Create Visible Light-Activatable Drugs.

Imidazoles are crucial structural components in a variety of small-molecule inhibitors designed to target different kinases in anticancer treatment. However, the effectiveness of such inhibitors is often hampered by nonspecific effects and the development of resistance. Photopharmacology provides a compelling solution by enabling external control over drug activity with spatiotemporal precision. Herein, we introduce a novel strategy for caging bioactive triarylimidazole-based drug molecules. This approach involves introducing a dialkylamino group as a photoremovable group on the carbon atom of the imidazole ring, which intrinsically modulates the core structure from planar imidazole to tetrahedral 2H-imidazole, enabling the caged compound to be selectively uncaged upon visible light exposure. We applied this innovative caging technique to SB431542, a triarylimidazole-based small-molecule inhibitor that targets the pivotal TGF-ß signaling pathway, the dysregulation of which is linked to several human diseases, including cancer. Our results demonstrated the selective inhibition of human breast cancer cell migration in vitro upon light activation, highlighting the potential of our approach to transform triarylimidazole-based drug molecules into visible light-activatable drugs, thereby facilitating spatiotemporal regulation of their pharmacological activity.

Pseudo-Luciferase Activity of the SARS-CoV-2 Spike Protein for Cypridina Luciferin.

Enzymatic reactions that involve a luminescent substrate (luciferin) and enzyme (luciferase) from luminous organisms enable a luminescence detection of target proteins and cells with high specificity, albeit that conventional assay design requires a prelabeling of target molecules with luciferase. Here, we report a luciferase-independent luminescence assay in which the target protein directly catalyzes the oxidative luminescence reaction of luciferin. The SARS-CoV-2 antigen (spike) protein catalyzes the light emission of Cypridina luciferin, whereas no such catalytic function was observed for salivary proteins. This selective luminescence reaction is due to the enzymatic recognition of the 3-(1-guanidino)propyl group in luciferin at the interfaces between the units of the spike protein, allowing a specific detection of the spike protein in human saliva without sample pretreatment. This method offers a novel platform to detect virus antigens simply and rapidly without genetic manipulation or antibodies.

Chaperonin GroEL hydrolyses ortho-nitrophenyl ß-galactoside.

We serendipitously found that chaperonin GroEL can hydrolyze ortho-nitrophenyl ß-galactoside (ONPG), a well-known substrate of the enzyme ß-galactosidase. The ONPG hydrolysis by GroEL follows typical enzyme kinetics. Our experiments and molecular docking studies suggest ONPG binding at the ATP binding site of GroEL.

Global Variations in Heart Failure Etiology, Management, and Outcomes.

Importance: Most epidemiological studies of heart failure (HF) have been conducted in high-income countries with limited comparable data from middle- or low-income countries. Objective: To examine differences in HF etiology, treatment, and outcomes between groups of countries at different levels of economic development. Design, Setting, and Participants: Multinational HF registry of 23 341 participants in 40 high-income, upper-middle-income, lower-middle-income, and low-income countries, followed up for a median period of 2.0 years. Main Outcomes and Measures: HF cause, HF medication use, hospitalization, and death. Results: Mean (SD) age of participants was 63.1 (14.9) years, and 9119 (39.1%) were female. The most common cause of HF was ischemic heart disease (38.1%) followed by hypertension (20.2%). The proportion of participants with HF with reduced ejection fraction taking the combination of a ß-blocker, renin-angiotensin system inhibitor, and mineralocorticoid receptor antagonist was highest in upper-middle-income (61.9%) and high-income countries (51.1%), and it was lowest in low-income (45.7%) and lower-middle-income countries (39.5%) (P < .001). The age- and sex- standardized mortality rate per 100 person-years was lowest in high-income countries (7.8 [95% CI, 7.5-8.2]), 9.3 (95% CI, 8.8-9.9) in upper-middle-income countries, 15.7 (95% CI, 15.0-16.4) in lower-middle-income countries, and it was highest in low-income countries (19.1 [95% CI, 17.6-20.7]). Hospitalization rates were more frequent than death rates in high-income countries (ratio = 3.8) and in upper-middle-income countries (ratio = 2.4), similar in lower-middle-income countries (ratio = 1.1), and less frequent in low-income countries (ratio = 0.6). The 30-day case-fatality rate after first hospital admission was lowest in high-income countries (6.7%), followed by upper-middle-income countries (9.7%), then lower-middle-income countries (21.1%), and highest in low-income countries (31.6%). The proportional risk of death within 30 days of a first hospital admission was 3- to 5-fold higher in lower-middle-income countries and low-income countries compared with high-income countries after adjusting for patient characteristics and use of long-term HF therapies. Conclusions and Relevance: This study of HF patients from 40 different countries and derived from 4 different economic levels demonstrated differences in HF etiologies, management, and outcomes. These data may be useful in planning approaches to improve HF prevention and treatment globally.

Structural effects of spike protein D614G mutation in SARS-CoV-2.

A single mutation from aspartate to glycine at position 614 has dominated all circulating variants of the severe acute respiratory syndrome coronavirus 2. D614G mutation induces structural changes in the spike (S) protein that strengthen the virus infectivity. Here, we use molecular dynamics simulations to dissect the effects of mutation and 630-loop rigidification on S-protein structure. The introduction of the mutation orders the 630-loop structure and thereby induces global structural changes toward the cryoelectron microscopy structure of the D614G S-protein. The ordered 630-loop weakens local interactions between the 614th residue and others in contrast to disordered structures in the wild-type protein. The mutation allosterically alters global interactions between receptor-binding domains, forming an asymmetric and mobile down conformation and facilitating transitions toward up conformation. The loss of salt bridge between D614 and K854 upon the mutation generally stabilizes S-protein protomer, including the fusion peptide proximal region that mediates membrane fusion. Understanding the molecular basis of D614G mutation is crucial as it dominates in all variants of concern, including Delta and Omicron.

Influenza vaccine to reduce adverse vascular events in patients with heart failure: a multinational randomised, double-blind, placebo-controlled trial.

BACKGROUND: Influenza increases the risk of cardiovascular events and deaths. We aimed to see whether influenza vaccination reduces death and vascular events in patients with heart failure. METHODS: We did a pragmatic, randomised, double-blind, placebo-controlled trial in 30 centres (mostly hospitals affliated with universities or a research institute) in ten countries in Asia, the Middle East, and Africa (7 in India, 4 in Philippines, 4 in Nigeria, 6 in China, 1 in Zambia, 2 in Mozambique, 3 in Saudi Arabia, 1 in Kenya, 1 in Uganda, and 1 in Zambia). Participants (aged ≥18 years; 52·1% female; not disaggregated by race or ethnicity) with heart failure (New York Heart Association class II, III, or IV) were randomly assigned (1:1) by a centralised web-based system with block randomisation stratified by site, to receive 0·5 ml intramuscularly once a year for up to 3 years of either inactivated standard dose influenza vaccine or placebo (saline). We excluded people who had received influenza vaccine in 2 of the previous 3 years, and those likely to require valve repair or replacement. Those who administered assigned treatments were not masked and had no further role in the study. Investigators, study coordinators, outcome adjudicators, and participants were masked to group assignment. The first of two co-primary outcomes was a first-event composite for cardiovascular death, non-fatal myocardial infarction, and non-fatal stroke, and the second was a recurrent-events composite for cardiovascular death, non-fatal myocardial infarction, non-fatal stroke, and hospitalisation for heart failure. Outcomes were assessed every 6 months in the intention-to-treat population. Secondary outcomes were all-cause death, cardiovascular death, non-fatal myocardial infarction, non-fatal stroke, all-cause hospitalisation, hospitalisation for heart failure, and pneumonia, both overall and during periods of peak influenza exposure. This study is registered with ClinicalTrials.gov, NCT02762851. FINDINGS: Between June 2, 2015, and Nov 21, 2021, we enrolled 5129 participants and randomly assigned (1:1) 2560 (50·0%) to influenza vaccine and 2569 (50·0%) to placebo. The first co-primary outcome occurred in 380 (14·8%) of 2560 participants in the vaccine group and 410 (16·0%) of 2569 participants in the placebo group (hazard ratio [HR] 0·93 [95% CI 0·81-1·07]; p=0·30). The second co-primary outcome occurred in 754 (29·5%) of 2560 participants in the vaccine group and 819 (31·9%) of 2569 participants in the placebo group; HR 0·92 [95% CI 0·84-1·02]; p=0·12). The secondary outcomes of all-cause hospitalisations (HR 0·84 [95% CI 0·74-0·97]; p=0·013) and pneumonia (HR 0·58 [0·42-0·80]; p=0·0006) were significantly reduced in the vaccine group compared with in the placebo group but there was no significant difference between groups for all-cause death, cardiovascular death, non-fatal myocardial infarction, non-fatal stroke, and hospitalisation for heart failure. In a prespecified analysis, in which events were limited to periods of peak influenza circulation, the first co-primary outcome, and the secondary outcomes of all-cause death, cardiovasular death, and pneumonia were significantly lower in the vaccinated group than in the placebo group, whereas the second co-primary outcome and the secondary outcomes of non-fatal myocardial infarction, non-fatal stroke, all-cause hospitalisation, and hospitalisation for heart failure were not significantly lower. INTERPRETATION: Although the prespecified co-primary outcomes during the entire period of observation were not statistically significant, the reduction during the peak influenza circulating period suggests that there is likely to be a clinical benefit of giving influenza vaccine, given the clear reduction in pneumonia, a moderate reduction in hospitalisations, and a reduction in cardiovascular events and deaths during periods of peak circulation of influenza. Taken in conjunction with previous trials and the observational studies, the collective data suggest benefit. FUNDING: UK Joint Global Health Trials Scheme and Canadian Institutes for Health Research Foundation.

Modified Protein-Water Interactions in CHARMM36m for Thermodynamics and Kinetics of Proteins in Dilute and Crowded Solutions.

Proper balance between protein-protein and protein-water interactions is vital for atomistic molecular dynamics (MD) simulations of globular proteins as well as intrinsically disordered proteins (IDPs). The overestimation of protein-protein interactions tends to make IDPs more compact than those in experiments. Likewise, multiple proteins in crowded solutions are aggregated with each other too strongly. To optimize the balance, Lennard-Jones (LJ) interactions between protein and water are often increased about 10% (with a scaling parameter, λ = 1.1) from the existing force fields. Here, we explore the optimal scaling parameter of protein-water LJ interactions for CHARMM36m in conjunction with the modified TIP3P water model, by performing enhanced sampling MD simulations of several peptides in dilute solutions and conventional MD simulations of globular proteins in dilute and crowded solutions. In our simulations, 10% increase of protein-water LJ interaction for the CHARMM36m cannot maintain stability of a small helical peptide, (AAQAA)3 in a dilute solution and only a small modification of protein-water LJ interaction up to the 3% increase (λ = 1.03) is allowed. The modified protein-water interactions are applicable to other peptides and globular proteins in dilute solutions without changing thermodynamic properties from the original CHARMM36m. However, it has a great impact on the diffusive properties of proteins in crowded solutions, avoiding the formation of too sticky protein-protein interactions.

The inherent flexibility of receptor binding domains in SARS-CoV-2 spike protein.

Spike (S) protein is the primary antigenic target for neutralization and vaccine development for the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). It decorates the virus surface and undergoes large motions of its receptor binding domains (RBDs) to enter the host cell. Here, we observe Down, one-Up, one-Open, and two-Up-like structures in enhanced molecular dynamics simulations, and characterize the transition pathways via inter-domain interactions. Transient salt-bridges between RBDA and RBDC and the interaction with glycan at N343B support RBDA motions from Down to one-Up. Reduced interactions between RBDA and RBDB in one-Up induce RBDB motions toward two-Up. The simulations overall agree with cryo-electron microscopy structure distributions and FRET experiments and provide hidden functional structures, namely, intermediates along Down-to-one-Up transition with druggable cryptic pockets as well as one-Open with a maximum exposed RBD. The inherent flexibility of S-protein thus provides essential information for antiviral drug rational design or vaccine development.

Clinical Profiles and Outcomes of Heart Failure in Five African Countries: Results from INTER-CHF Study.

Background: A wide knowledge gap exists on the clinical profiles and outcomes of heart failure (HF) in sub-Saharan Africa. Objectives: To determine the clinical profiles and outcomes of HF patients from five African countries. Methods: The INTERnational Congestive Heart Failure Study (INTER-CHF) is a prospective, multicenter cohort study. A total of 1,294 HF patients were consecutively recruited from Nigeria (383 patients), South Africa (169 patients), Sudan (501 patients), Uganda (151patients), and Mozambique (90 patients). HF was defined according to the Boston criteria for diagnosis. Cognitive function was assessed using the Montreal Cognitive Assessment (MoCA) score. Results: Of the 1294 patients, 51.4% were recruited as out-patients, 53.7% had HF with reduced ejection fraction (EF), 30.1% had HF with mid-range EF and 16.2% had HF with preserved EF (16.2%). The commonest etiologies of HF were hypertensive heart disease (35%) and ischemic heart disease (20%). The mean MoCA score was highest in Uganda (24.3 ± 1.1) and lowest in Sudan (13.6 ± 0.3). Prescriptions for guideline-recommended HF therapies were poor; only 1.2% of South African patients received an Implantable Cardioverter Defibrillator, and none of the patients received Cardiac Resynchronised Therapy. The composite outcome of death or HF hospitalization at one year among the patients was highest in Sudan (59.7%) and lowest in Mozambique (21.1%). Six variables were associated with higher mortality risk, while digoxin use (adjusted hazard ratio [aHR]: 0.69; 95% confidence interval [CI]: 0.49-0.97; p = 0.034) and 10mmHg unit increase in systolic blood pressure (aHR 0.86; 95%CI 0.81-0.93; p < 0.001) were associated with lower risk for mortality. Conclusions: This is the largest HF study in Africa that included in- and out-patients from the West, East, North, Central and South African sub-regions. Clinically relevant differences, including cognitive functional impairment, were found between the involved countries.

Health-Related Quality of Life and Mortality in Heart Failure: The Global Congestive Heart Failure Study of 23 000 Patients From 40 Countries.

BACKGROUND: Poor health-related quality of life (HRQL) is common in heart failure (HF), but there are few data on HRQL in HF and the association between HRQL and mortality outside Western countries. METHODS: We used the Kansas City Cardiomyopathy Questionnaire-12 (KCCQ-12) to record HRQL in 23 291 patients with HF from 40 countries in 8 different world regions in the G-CHF study (Global Congestive Heart Failure). We compared standardized KCCQ-12 summary scores (adjusted for age, sex, and markers of HF severity) among regions (scores range from 0 to 100, with higher score indicating better HRQL). We used multivariable Cox regression with adjustment for 15 variables to assess the association between KCCQ-12 summary scores and the composite of all-cause death, HF hospitalization, and each component over a median follow-up of 1.6 years. RESULTS: The mean age of participants was 65 years; 61% were men; 40% had New York Heart Association class III or IV symptoms; and 46% had left ventricular ejection fraction ≥40%. Average HRQL differed between regions (lowest in Africa [mean± SE, 39.5±0.3], highest in Western Europe [62.5±0.4]). There were 4460 (19%) deaths, 3885 (17%) HF hospitalizations, and 6949 (30%) instances of either event. Lower KCCQ-12 summary score was associated with higher risk of all outcomes; the adjusted hazard ratio (HR) for each 10-unit KCCQ-12 summary score decrement was 1.18 (95% CI, 1.17-1.20) for death. Although this association was observed in all regions, it was less marked in South Asia, South America, and Africa (weakest association in South Asia: HR, 1.08 [95% CI, 1.03-1.14]; strongest association in Eastern Europe: HR, 1.31 [95% CI, 1.21-1.42]; interaction P<0.0001). Lower HRQL predicted death in patients with New York Heart Association class I or II and III or IV symptoms (HR, 1.17 [95% CI, 1.14-1.19] and HR, 1.14 [95% CI, 1.12-1.17]; interaction P=0.13) and was a stronger predictor for the composite outcome in New York Heart Association class I or II versus class III or IV (HR 1.15 [95% CI, 1.13-1.17] versus 1.09 [95% CI, [1.07-1.11]; interaction P<0.0001). HR for death was greater in ejection fraction ≥40 versus <40% (HR, 1.23 [95% CI, 1.20-1.26] and HR, 1.15 [95% CI, 1.13-1.17]; interaction P<0.0001). CONCLUSION: HRQL is a strong and independent predictor of all-cause death and HF hospitalization across all geographic regions, in mildly and severe symptomatic HF, and among patients with preserved and reduced ejection fraction. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT03078166.

Unraveling the Coupling between Conformational Changes and Ligand Binding in Ribose Binding Protein Using Multiscale Molecular Dynamics and Free-Energy Calculations.

Conformational changes of proteins upon ligand binding are usually explained in terms of several mechanisms including the induced fit, conformational selection, or their mixtures. Due to the slow time scales, conventional molecular dynamics (cMD) simulations based on the atomistic models cannot easily simulate the open-to-closed conformational transition in proteins. In our previous study, we have developed an enhanced sampling scheme (generalized replica exchange with solute tempering selected surface charged residues: gREST_SSCR) for multidomain proteins and applied it to ligand-mediated conformational changes in the G134R mutant of ribose-binding protein (RBPG134R) in solution. The free-energy landscape (FEL) of RBPG134R in the presence of a ribose at the binding site included the open and closed states and two intermediates, open-like and closed-like forms. Only the open and open-like forms existed in the FEL without a ribose. In the current study, the coupling between the conformational changes and ligand binding is further investigated using coarse-grained MD, multiple atomistic cMD, and free-energy calculations. The ribose is easily dissociated from the binding site of wild-type RBP and RBPG134R in the cMD simulations starting from the open and open-like forms. In contrast, it is stable at the binding site in the simulations from the closed and closed-like forms. The free-energy calculations provide the binding affinities of different structures, supporting the results of cMD simulations. Importantly, cMD simulations from the closed-like structures reveal transitions toward the closed one in the presence of a bound ribose. On the basis of the computational results, we propose a molecular mechanism in which conformational selection and induced fit happen in the first and second halves of the open-to-closed transition in RBP, respectively.

Elucidation of interactions regulating conformational stability and dynamics of SARS-CoV-2 S-protein.

The ongoing COVID-19 pandemic caused by the new coronavirus, SARS-CoV-2, calls for urgent developments of vaccines and antiviral drugs. The spike protein of SARS-CoV-2 (S-protein), which consists of trimeric polypeptide chains with glycosylated residues on the surface, triggers the virus entry into a host cell. Extensive structural and functional studies on this protein have rapidly advanced our understanding of the S-protein structure at atomic resolutions, although most of these structural studies overlook the effect of glycans attached to the S-protein on the conformational stability and functional motions between the inactive down and active up forms. Here, we performed all-atom molecular dynamics simulations of both down and up forms of a fully glycosylated S-protein in solution as well as targeted molecular dynamics simulations between them to elucidate key interdomain interactions for stabilizing each form and inducing the large-scale conformational transitions. The residue-level interaction analysis of the simulation trajectories detects distinct amino acid residues and N-glycans as determinants on conformational stability of each form. During the conformational transitions between them, interdomain interactions mediated by glycosylated residues are switched to play key roles on the stabilization of another form. Electrostatic interactions, as well as hydrogen bonds between the three receptor binding domains, work as driving forces to initiate the conformational transitions toward the active form. This study sheds light on the mechanisms underlying conformational stability and functional motions of the S-protein, which are relevant for vaccine and antiviral drug developments.

A multinational registry to study the characteristics and outcomes of heart failure patients: The global congestive heart failure (G-CHF) registry.

The goal of the global congestive heart failure (G-CHF) registry is to collect comparative international data on heart failure characteristics, management, and outcomes and to better understand the determinants that impact the clinical course of heart failure. METHODS: G-CHF is a multicenter, prospective cohort study of adult patients with a new or prior clinical diagnosis of heart failure. We have enrolled 23,047 participants from 257 centers in 40 countries from 8 major geographic regions of the world, with recruitment ongoing. Approximately 4,000 participants will also participate in substudies to assess frailty, comorbidity, diet, barriers to care, biomarkers, and planned detailed echocardiographic analyses. Follow-up is planned for a period of 5 years. The primary outcome is cause-specific mortality. Key secondary outcomes include hospitalizations, quality of life, and major cardiovascular and noncardiovascular outcomes. A total of 31.9% of participants were enrolled as inpatients. Thus far, mean age of the cohort at baseline is 63.1 years, and 60.8% are male. Participants most commonly have heart failure with reduced ejection fraction (53.6%) followed by preserved ejection fraction (24.2%) and midrange ejection fraction (20.6%). The most common causes of heart failure are ischemic (37.8%) followed by hypertensive (20.0%), idiopathic (15.1%), and valvular disease (8.8%). CONCLUSION: G-CHF will provide a greater understanding of the characteristics of the global heart failure population, variations in its management, clinical outcomes, and what continues to impact morbidity and mortality in this high-risk population.

Exploring Large Domain Motions in Proteins Using Atomistic Molecular Dynamics with Enhanced Conformational Sampling.

Conformational transitions in multidomain proteins are essential for biological functions. The Apo conformations are typically open and flexible, while the Holo states form more compact conformations stabilized by protein-ligand interactions. Unfortunately, the atomically detailed mechanisms for such open-closed conformational changes are difficult to be accessed experimentally as well as computationally. To simulate the transitions using atomistic molecular dynamics (MD) simulations, efficient conformational sampling algorithms are required. In this work, we propose a new approach based on generalized replica-exchange with solute tempering (gREST) for exploring the open-closed conformational changes in multidomain proteins. Wherein, selected surface charged residues in a target protein are defined as the solute region in gREST simulation and the solute temperatures are different in replicas and exchanged between them to enhance the domain motions. This approach is called gREST selected surface charged residues (gREST_SSCR) and is applied to the Apo and Holo states of ribose binding protein (RBP) in solution. The conformational spaces sampled with gREST_SSCR are much wider than those with the conventional MD, sampling open-closed conformational changes while maintaining RBP domains' stability. The free-energy landscapes of RBP in the Apo and Holo states are drawn along with twist and hinge angles of the two moving domains. The inter-domain salt-bridges that are not observed in the experimental structures are also important in the intermediate states during the conformational changes.

Randomized controlled trial of influenza vaccine in patients with heart failure to reduce adverse vascular events (IVVE): Rationale and design.

BACKGROUND: Influenza is associated with an increase in the risk of cardiac and other vascular events. Observational data and small randomized trials suggest that influenza vaccination may reduce such adverse vascular events. RESEARCH DESIGN AND METHODS: In a randomized controlled trial patients with heart failure are randomized to receive either inactivated influenza vaccine or placebo annually for 3 years. Patients aged ≥18 years with a clinical diagnosis of heart failure and NYHA functional class II, III and IV are eligible. Five thousand patients from 10 countries where influenza vaccination is not common (Asia, the Middle East, and Africa) have been enrolled. The primary outcome is a composite of the following: cardiovascular death, non-fatal myocardial infarction, non-fatal stroke and hospitalizations for heart failure using standardized criteria. Analyses will be based on comparing event rates between influenza vaccine and control groups and will include time to event, rate comparisons using Poisson methods, and logistic regression. The analysis will be conducted by intention to treat i.e. patients will be analyzed in the group in which they were assigned. Multivariable secondary analyses to assess whether variables such as age, sex, seasonality modify the benefits of vaccination are also planned for the primary outcome. CONCLUSION: This is the largest randomized trial to test if influenza vaccine compared to control reduces adverse vascular events in high risk individuals. TRIAL REGISTRATION NUMBER: Clinicaltrials.govNCT02762851.

Prospective Study of Tricuspid Regurgitation Associated With Permanent Leads After Cardiac Rhythm Device Implantation.

BACKGROUND: Tricuspid regurgitation (TR) has been associated with cardiac rhythm device (CRD) implantation with intracardiac lead insertion. However, data on the incidence of postdevice TR are limited and largely from retrospective studies. We hypothesized that permanent lead implantation would be associated with an increase in TR. METHODS: We prospectively included consecutive patients with a clinical indication for CRD. Patients underwent transthoracic echocardiography 1 month before and 1 year after CRD implantation. RESULTS: A total of 328 patients were prospectively enrolled (69 ± 15 years, 38% female). Echocardiograms before and 1 year after CRD were available in 290 patients (15 died, 23 lost to follow-up). Compared with baseline, there was a significant change in TR grade 1 year after CRD insertion (no/trivial TR: 66% vs 29%; mild TR: 29% vs 61%; moderate TR: 3% vs 8%; severe TR 2% vs 2%; P < 0.001 for an increase in TR by at least 1 grade). Compared with baseline, there was a higher prevalence of moderate or severe TR in the 247 patients with CRD without cardiac resynchronization therapy (4% vs 10%, P = 0.004), but no progression in the 43 patients who received cardiac resynchronization therapy (14% vs 11%, P = 1). Multivariable analysis in the patients with less than moderate TR at baseline (n = 274) showed that only a history of atrial fibrillation was independently associated with progression to moderate or severe TR after correction for baseline TR grade (P = 0.013). CONCLUSIONS: One year after endocardial lead insertion, there was a 5% increase in the prevalence of moderate or severe TR, which may be clinically relevant.

Similarities and Differences between Thymine(6-4)Thymine/Cytosine DNA Lesion Repairs by Photolyases.

Photolyases are ancient enzymes that harvest sunlight to repair DNA pyrimidine lesions such as pyrimidine(6-4)pyrimidone and cyclobutane dimers. Particularly, (6-4) photolyase ((6-4)PHR) plays an important role in maintaining genetic integrity by repairing thymine(6-4)thymine (T(6-4)T) and thymine(6-4)cytosine (T(6-4)C) photolesions. The majority of (6-4)PHR studies have been performed on the basis of the former's activity and assuming the equivalence of the two repair mechanisms, although the latter's activity remains poorly studied. Here, we describe investigations of the repair process of the T(6-4)C dimer using several computational methods from molecular dynamics (MD) simulations to large quantum mechanical/molecular mechanical approaches. Two possible mechanisms, the historically proposed azetidine four-member ring intermediate and the free NH3 formation pathways, were considered. The MD results predicted that important active site histidine residues employed for the repair of the T(6-4)C dimer have protonation states similar to those seen in the (6-4)PHR/T(6-4)T complex. More importantly, despite chemical differences between the two substrates, a similar repair mechanism was identified: His365 protonates NH2, resulting in formation/activation mechanism of a free NH3, inducing NH2 transfer to the 5' base, and ultimately leading to pyrimidine restoration. This reaction is thermodynamically favorable with a rate-limiting barrier of 20.4 kcal mol-1. In contrast, the azetidine intermediate is unfeasible, possessing an energy barrier of 60 kcal mol-1; this barrier is similar to that predicted for the oxetane intermediate in T(6-4)T repair. Although both substrates are repaired with comparable quantum yields, the reactive complex in T(6-4)C was shown to be a 3' base radical with a lower driving force for back electron transfer combined with higher energy barrier for catalysis. These results showed the similarity in the general repair mechanisms between the two substrates while emphasizing differences in the electron dynamics in the repair cycle.