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Atrial fibrillation (AF) is associated with extracellular matrix (ECM) remodelling and often coexists with myocardial fibrosis (MF); however, the causality of these conditions is not well established. We aim to corroborate AF to MF causality by quantifying left atrial (LA) fibrosis in cardiac magnetic resonance (CMR) images after persistent rapid ventricular pacing and subsequent AF using a canine model and histopathological validation. Twelve canines (9 experimental, 3 control) underwent baseline 3D LGE-CMR imaging at 3T followed by insertion of a pacing device and 5 weeks of rapid ventricular pacing to induce AF (experimental) or no pacing (control). Following the 5 weeks, pacing devices were removed to permit CMR imaging followed by excision of the hearts and histopathological imaging. LA myocardial segmentation was performed manually at baseline and post-pacing to permit volumetric %MF quantification using the image intensity ratio (IIR) technique, wherein fibrosis was defined as pixels > mean LA myocardium intensity + 2SD. Volumetric %MF increased by an average of 2.11 ± 0.88% post-pacing in 7 of 9 experimental dogs. While there was a significant difference between paired %MF measurements from baseline to post-pacing in experimental dogs (P = 0.019), there was no significant change in control dogs (P = 0.019 and P = 0.5, Wilcoxon signed rank tests). The median %MF for paced animals was significantly greater than that of non-paced dogs at the 5-week post-insertion time point (P = 0.009, Mann Whitney U test). Histopathological imaging yielded an average %MF of 19.42 ± 4.80% (mean ± SD) for paced dogs compared to 1.85% in one control dog. Persistent rapid ventricular pacing and subsequent AF leads to an increase in LA fibrosis volumes measured by the IIR technique; however, quantification is limited by inherent image acquisition parameters and observer variability.

BackgroundAfter myocardial infarction, fibrosis and an ongoing dysregulated inflammatory response have been shown to lead to adverse cardiac remodeling. FDG PET is an imaging modality sensitive to inflammation as long as suppression protocols are observed while gadolinium enhanced MRI can be used to determine extracellular volume (ECV), a measure of fibrosis. In patients, glucose suppression is achieved variously through a high fat diet, fasting and injection of heparin. To emulate this process in canines, a heparin injection and lipid infusion are used, leading to similar fatty acids in the blood. The aim of this study was to examine the effect of glucose suppression on the uptake of FDG in the infarcted myocardial tissue and also on the determination of ECV in both the infarcted tissue and in the myocardium remote to the zone of infarction during a long constant infusion of FDG and Gd-DTPA.ResultsExtracellular volume was affected neither by suppression nor the length of the constant infusion in remote and infarcted tissue. Metabolic rate of glucose in infarcted tissue decreased during and after suppression of glucose uptake by lipid infusion and heparin injection. An increase in fibrosis and inflammatory cells was found in the center of the infarct as compared to remote tissue.ConclusionThe decrease in the metabolic rate of glucose in the infarcted tissue suggests that inflammatory cells may be affected by glucose suppression through heparin injection and lipid infusion.

Background: After myocardial infarction (MI), fibrosis and an ongoing dysregulated inflammatory response are associated with adverse cardiac remodeling. Fluorodeoxyglucose (FDG) positron emission tomography (PET) is sensitive to inflammation provided suppression protocols are implemented to restrict the uptake of glucose in myocytes. Magnetic resonance imaging can be used to determine extracellular volume, a surrogate measure of fibrosis. In some cases, patients present with markedly reduced flow in the setting of a large infarct, i.e. microvascular obstruction, restricting the delivery of FDG and contrast agents. To overcome this problem, a constant infusion was explored as an alternative to the clinical standard bolus injection. This led to three objectives: a) comparison of the constant infusion to the bolus injection in healthy canines, b) investigation of the potential of the constant infusion to discriminate post-MI tissue types, and c) determination of the efficacy of the suppression protocol and its effect on extracellular volume. Methods: All imaging was done with a hybrid PET/MRI scanner. MRI images were used to determine the regions of interest: remote, injured and obstructed myocardium. PET images were used to determine inflammation. To compare the injection strategies, five healthy canines were examined with all three. Subsequently, eight animals were imaged at baseline and days 3, 7, 14, 21, and 42 post-MI using a 60-min infusion. Lastly, seven animals were imaged at baseline and day 5 post-MI using a 150-min infusion. Forty minutes into the infusion, suppression of glucose uptake in myocytes was started. Results: No significant differences in terms of glucose metabolism and extracellular volume were seen in healthy myocardium between the three injection strategies: bolus injection, constant infusion and bolus followed by constant infusion, showing that a strategy involving the constant infusion produced similar results as to those obtained with a bolus injection. Following MI, a significant increase in extracellular volume was seen in remote tissue on days 14 and 21, suggesting an inflammatory response. During the 150-min infusion, suppression of myocardial glucose uptake had the unexpected result of reducing FDG uptake in inflammatory cells within the infarcted area. Conclusion: This research showed the possibility of using a constant infusion of Gd-DTPA and FDG to investigate inflammation within the entire myocardium. The finding that suppression affected inflammatory cells highlights the need for tracers which do not rely on myocardial glucose suppression.

We characterise from first principles the structure and bonding in 2D heterosystems made of bilayers or trilayers of graphene and graphene-like-materials (GLMs), stacked on top of each other, and functionalized using hydrogen. The effects of electron band gap opening and tuning, as well as formation of strongly bonded multilayers have been predicted. The linear and nonlinear optical and vibrational spectra were modelled for hydrogenated alternating graphene monolayers with insulating hexagonal boron nitride (h-BN) films. Here we focus mostly on the structural aspect of the 2D heterosystems. The simulated atomic and related electron structures indicate that submonolayer hydrogenation of the outer surfaces of multilayer systems induces covalent interlayer bonds and enables electron gap engineering in otherwise gapless graphene or wide-band gap h-BN. Calculated structural, vibrational, electronic and optical properties of the systems of interest aim to enabling in-situ noninvasive characterization of graphene based multilayers.

This dissertation uses a variety of approaches to examine the causative role of feeding practices during infancy and childhood in the development of early childhood caries.

Declaring that the primary question each advertising manager must ask himself now is, \"How can advertising generally, and my advertising in particular. contribute to winning the war?\" G. D. Crain, Jr., publisher of \"Advertising Age,\" told the Cleveland Advertising Club recently that \"advertising can function in the national interest more effectively now than at any other time.\"

It is very often true that men who urgently need insurance for the protection of their dependents do not carry as much as they can and should. Such men may be uneasy under the sharp pressure of duty unfulfilled. But they endure that rather than forego the transitory satisfactions into which they stubbornly put money which would safeguard their dependents from dire trouble, if not complete disaster.

Suggestions for determining the housing needs of a community of workers and preparing to supply them

Deciding when to return to sport after injury is complex and multifactorial—an exercise in risk management. Return to sport decisions are made every day by clinicians, athletes and coaches, ideally in a collaborative way. The purpose of this consensus statement was to present and synthesise current evidence to make recommendations for return to sport decision-making, clinical practice and future research directions related to returning athletes to sport. A half day meeting was held in Bern, Switzerland, after the First World Congress in Sports Physical Therapy. 17 expert clinicians participated. 4 main sections were initially agreed upon, then participants elected to join 1 of the 4 groups—each group focused on 1 section of the consensus statement. Participants in each group discussed and summarised the key issues for their section before the 17-member group met again for discussion to reach consensus on the content of the 4 sections. Return to sport is not a decision taken in isolation at the end of the recovery and rehabilitation process. Instead, return to sport should be viewed as a continuum, paralleled with recovery and rehabilitation. Biopsychosocial models may help the clinician make sense of individual factors that may influence the athlete's return to sport, and the Strategic Assessment of Risk and Risk Tolerance framework may help decision-makers synthesise information to make an optimal return to sport decision. Research evidence to support return to sport decisions in clinical practice is scarce. Future research should focus on a standardised approach to defining, measuring and reporting return to sport outcomes, and identifying valuable prognostic factors for returning to sport.

Genome-wide association studies (GWAS) have identified thousands of genetic variants linked to the risk of human disease. However, GWAS have so far remained largely underpowered in relation to identifying associations in the rare and low-frequency allelic spectrum and have lacked the resolution to trace causal mechanisms to underlying genes 1 . Here we combined whole-exome sequencing in 392,814 UK Biobank participants with imputed genotypes from 260,405 FinnGen participants (653,219 total individuals) to conduct association meta-analyses for 744 disease endpoints across the protein-coding allelic frequency spectrum, bridging the gap between common and rare variant studies. We identified 975 associations, with more than one-third being previously unreported. We demonstrate population-level relevance for mutations previously ascribed to causing single-gene disorders, map GWAS associations to likely causal genes, explain disease mechanisms, and systematically relate disease associations to levels of 117 biomarkers and clinical-stage drug targets. Combining sequencing and genotyping in two population biobanks enabled us to benefit from increased power to detect and explain disease associations, validate findings through replication and propose medical actionability for rare genetic variants. Our study provides a compendium of protein-coding variant associations for future insights into disease biology and drug discovery. A meta-analysis combining whole-exome sequencing data from UK Biobank participants and imputed genotypes from FinnGen participants enables identification of genetic associations with human disease in the rare and low-frequency allelic spectrum