We sought to determine the relationship between changes in natriuretic peptides and symptoms as a consequence of introducing beta-blocker therapy, in patients with chronic heart failure (CHF) and ...persistent atrial fibrillation (AF).
In a randomised, double-blind, placebo-controlled study involving 47 patients with CHF and persistent AF (mean age 68 years and 62% men), we analysed the individual change (Δ) in B-type natriuretic peptide (BNP) level to the introduction of carvedilol (titrated to a target dose of 25 mg twice daily, group A) or placebo (group B) in addition to background treatment with digoxin. Symptoms score, 6-min walk distance, New York Heart Association (NYHA) class, left ventricular ejection fraction (LVEF), heart rate (24-hour ECG) and BNP were measured at baseline and at 4 months.
LVEF (Δ median +5 vs. +0.4, p = 0.048), symptoms score (Δ median -4 vs. 0, p = 0.04), NYHA class (Δ median -33% vs. +3% in NYHA class 3-4, p = 0.046) and heart rate Δ median 24-hour ventricular rate (VR) -19 vs. -2, p < 0.0001 improved with combination therapy of digoxin and carvedilol compared to digoxin alone, but BNP (Δ median +28 vs. -6 , p = 0.11) trended in the opposite direction. There was no relationship between the degree of symptomatic improvement or VR control and BNP response.
After the introduction of carvedilol, clinical outcome appears unrelated to BNP changes in patients with CHF and AF. Changes in BNP cannot be used as a marker of clinical response in terms of symptoms or cardiac function in this setting.
Cardiovascular magnetic resonance (CMR) image acquisition techniques during exercise typically requires either transient cessation of exercise or complex post-processing, potentially compromising ...clinical utility. We evaluated the feasibility and reproducibility of a navigated image acquisition method for ventricular volumes assessment during continuous physical exercise.
Ten healthy volunteers underwent supine cycle ergometer (Lode) exercise CMR on two separate occasions using a free-breathing, multi-shot, navigated, balanced steady-state free precession cine pulse sequence. Images were acquired at 3-stages, baseline and during steady-state exercise at 55% and 75% maximal heart rate (HR
), based on a prior supine cardiopulmonary exercise test. Intra-and inter-observer variability and inter-scan reproducibility were derived. Clinical feasibility was tested in a separate cohort of patients with severe mitral regurgitation (n=6).
End-diastolic volume (EDV) of both LV and RV decreased during exercise at 55% and 75% HR
, although a reduction in RVEDV index was only observed at 75% HR
. Ejection fractions (EF) for both ventricles were significantly higher at 75% HR
compared to their respective baselines (LVEF 68%±3%
58%±5%, P=0.001; RVEF 66%±4%
58%±7%, P=0.02). Intra-observer and inter-observer reproducibility of LV parameters was excellent at all 3-stages. Although measurements of RVESV were more variable during exercise, the reproducibility of both RVEF and RV cardiac index was excellent (CV <10%). Inter-scan LV and RV ejection fraction were highly reproducible at all 3 stages, although inter-scan reproducibility of indexed RVESV was only moderate. The protocol was well tolerated by all patients.
Exercise CMR using a free-breathing, multi-shot, navigated cine imaging method allows simultaneous assessment of left and right ventricular volumes during
exercise. Intra- and inter-observer reproducibility were excellent. Inter-scan LV and RV ejection fraction were also highly reproducible.
IMPORTANCE: Unrecognized obstructive sleep apnea increases cardiovascular risks in the general population, but whether obstructive sleep apnea poses a similar risk in the perioperative period remains ...uncertain. OBJECTIVES: To determine the association between obstructive sleep apnea and 30-day risk of cardiovascular complications after major noncardiac surgery. DESIGN, SETTING, AND PARTICIPANTS: Prospective cohort study involving adult at-risk patients without prior diagnosis of sleep apnea and undergoing major noncardiac surgery from 8 hospitals in 5 countries between January 2012 and July 2017, with follow-up until August 2017. Postoperative monitoring included nocturnal pulse oximetry and measurement of cardiac troponin concentrations. EXPOSURES: Obstructive sleep apnea was classified as mild (respiratory event index REI 5-14.9 events/h), moderate (REI 15-30), and severe (REI >30), based on preoperative portable sleep monitoring. MAIN OUTCOMES AND MEASURES: The primary outcome was a composite of myocardial injury, cardiac death, heart failure, thromboembolism, atrial fibrillation, and stroke within 30 days of surgery. Proportional-hazards analysis was used to determine the association between obstructive sleep apnea and postoperative cardiovascular complications. RESULTS: Among a total of 1364 patients recruited for the study, 1218 patients (mean age, 67 SD, 9 years; 40.2% women) were included in the analyses. At 30 days after surgery, rates of the primary outcome were 30.1% (41/136) for patients with severe OSA, 22.1% (52/235) for patients with moderate OSA, 19.0% (86/452) for patients with mild OSA, and 14.2% (56/395) for patients with no OSA. OSA was associated with higher risk for the primary outcome (adjusted hazard ratio HR, 1.49 95% CI, 1.19-2.01; P = .01); however, the association was significant only among patients with severe OSA (adjusted HR, 2.23 95% CI, 1.49-3.34; P = .001) and not among those with moderate OSA (adjusted HR, 1.47 95% CI, 0.98-2.09; P = .07) or mild OSA (adjusted HR, 1.36 95% CI, 0.97-1.91; P = .08) (P = .01 for interaction). The mean cumulative duration of oxyhemoglobin desaturation less than 80% during the first 3 postoperative nights in patients with cardiovascular complications (23.1 95% CI, 15.5-27.7 minutes) was longer than in those without (10.2 95% CI, 7.8-10.9 minutes) (P < .001). No significant interaction effects on perioperative outcomes were observed with type of anesthesia, use of postoperative opioids, and supplemental oxygen therapy. CONCLUSIONS AND RELEVANCE: Among at-risk adults undergoing major noncardiac surgery, unrecognized severe obstructive sleep apnea was significantly associated with increased risk of 30-day postoperative cardiovascular complications. Further research would be needed to assess whether interventions can modify this risk.
This study aimed to explore changes in psychological responses (perceived stress, traumatic stress, stigma, coping) over time in residents, as well as their predictors. The level of perceived stress, ...traumatic stress, stigma, and coping responses were assessed using the Perceived Stress Scale, Impact of Event-Revised, Healthcare Workers Stigma Scale, and Brief Coping Orientation to Problems Experienced (COPE) Inventory, respectively. We collected responses from 274 residents at baseline and 221 residents at 3 months follow-up (timepoint 2) from the National Healthcare Group (NHG) residency programs in Singapore. All residents reported lower perceived stress and lower perceived stigma compared to baseline. Use of avoidance coping was associated with all three psychological responses (perceived stress, traumatic stress, and stigma) across the two timepoints. Compared to baseline, specific factors associated with perceived stress and traumatic stress at timepoint 2 were living alone, less problem solving, and seeking social support. Residency programs should encourage active coping strategies (e.g., seeking social support, positive thinking, problem solving) among residents, and proactively identify residents who may be at higher risk of psychological sequelae due to circumstances that contribute to isolation.
Genomes are organized into high-level three-dimensional structures, and DNA elements separated by long genomic distances can in principle interact functionally. Many transcription factors bind to ...regulatory DNA elements distant from gene promoters. Although distal binding sites have been shown to regulate transcription by long-range chromatin interactions at a few loci, chromatin interactions and their impact on transcription regulation have not been investigated in a genome-wide manner. Here we describe the development of a new strategy, chromatin interaction analysis by paired-end tag sequencing (ChIA-PET) for the de novo detection of global chromatin interactions, with which we have comprehensively mapped the chromatin interaction network bound by oestrogen receptor alpha (ER-alpha) in the human genome. We found that most high-confidence remote ER-alpha-binding sites are anchored at gene promoters through long-range chromatin interactions, suggesting that ER-alpha functions by extensive chromatin looping to bring genes together for coordinated transcriptional regulation. We propose that chromatin interactions constitute a primary mechanism for regulating transcription in mammalian genomes.
Celotno besedilo
Dostopno za:
DOBA, IJS, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
COVID-19 pathogenesis is associated with an exaggerated immune response. However, the specific cellular mediators and inflammatory components driving diverse clinical disease outcomes remain poorly ...understood. We undertook longitudinal immune profiling on both whole blood and peripheral blood mononuclear cells (PBMCs) of hospitalized patients during the peak of the COVID-19 pandemic in the UK. Here, we report key immune signatures present shortly after hospital admission that were associated with the severity of COVID-19. Immune signatures were related to shifts in neutrophil to T cell ratio, elevated serum IL-6, MCP-1 and IP-10, and most strikingly, modulation of CD14
monocyte phenotype and function. Modified features of CD14
monocytes included poor induction of the prostaglandin-producing enzyme, COX-2, as well as enhanced expression of the cell cycle marker K
-67. Longitudinal analysis revealed reversion of some immune features back to the healthy median level in patients with a good eventual outcome. These findings identify previously unappreciated alterations in the innate immune compartment of COVID-19 patients and lend support to the idea that therapeutic strategies targeting release of myeloid cells from bone marrow should be considered in this disease. Moreover, they demonstrate that features of an exaggerated immune response are present early after hospital admission suggesting immune-modulating therapies would be most beneficial at early timepoints.
•A method to produce the dengue methyltransferase without a bound SAM is presented.•The enzyme retains enzymatic activity.•The high-resolution crystal structure of the free MTase shows there is no ...conformational change on SAM binding.•This allows rational drug discovery of compounds that compete with SAM binding.•This is demonstrated by solving the crystal structure of DENV MTase bound to Sinefungin.
Flavivirus methyltransferase is a genetically-validated antiviral target. Crystal structures of almost all available flavivirus methyltransferases contain S-adenosyl-L-methionine (SAM), the methyl donor molecule that co-purifies with the enzymes. This raises a possibility that SAM is an integral structural component required for the folding of dengue virus (DENV) methyltransferase. Here we exclude this possibility by solving the crystal structure of DENV methyltransferase without SAM. The SAM ligand was removed from the enzyme through a urea-mediated denaturation-and-renaturation protocol. The crystal structure of the SAM-depleted enzyme exhibits a vacant SAM-binding pocket, with a conformation identical to that of the SAM-enzyme co-crystal structure. Functionally, equivalent enzymatic activities (N-7 methylation, 2′-O methylation, and GMP-enzyme complex formation) were detected for the SAM-depleted and SAM-containing recombinant proteins. These results clearly indicate that the SAM molecule is not an essential component for the correct folding of DENV methyltransferase. Furthermore, the results imply a potential antiviral approach to search for inhibitors that can bind to the SAM-binding pocket and compete against SAM binding. To demonstrate this potential, we have soaked crystals of DENV methyltransferase without a bound SAM with the natural product Sinefungin and show that preformed crystals are capable of binding ligands in this pocket.
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