Myocardial Deformation Imaging Meta-Analysis in Two Cohorts of Patients from UAE and Heart Hospital Hamadmedical Corporation: A Potential Role in Assessment of Coronary Artery Disease Severity and Myocardial Viability

Introduction: The increasing prevalence of heart failure (HF) in coronary artery disease (CAD) urgently requires the establishment of new imaging techniques for early diagnosis and also to guide treatment of patients presented with acute coronary syndromes (ACS). Conventional echocardiography (CE) and electrocardiogram (ECG) are the gold standard methods in assessing myocardial ischemia (MI) and the function of the heart in patients with coronary artery disease (CAD). The lack of ST elevation by ECG and regional wall motion abnormalities by CE in non-ST segment elevation myocardial infarction (NSTEACS) in ACS patients reflect limited sensitivity of ECG and CE in identifying patients with acute coronary occlusion (ACO) and proper assessment of myocardial viability. Aim of this study: This study now evaluates the ability of strain parameters in grading the severity of CAD to detect myocardial viability in ACS through a comparative meta-analysis in two cohorts of patients living in the UAE and Qatar. The study investigates the diagnostic accuracy of left ventricular longitudinal systolic strain function (GLS) by 2D-speckle tracking echocardiography (2D-STE), Territorial Longitudinal Strain (TLS) analysis and post systolic strain (PSS) in ACS patients admitted at the emergency departments. All the patients had acute chest pain which is highly suggestive of NSTEACS along with coronary angiography (CA). Methods: The study recruited two groups, comprising of 347 patients, who were presented with acute coronary syndrome (NSTEACS) at the emergency department. The first group had 214 consecutive patients who had acute chest pain and high-risk profile and they were admitted to the emergency department at Eastern Emirates Hospitals, El-Fujairah-Dibba (EEEH), UAE. The second group consisted of 133 from emergency department at Heart Hospital- Hamad Medical Corporation (HHHMC), Qatar. In both groups, 85% of the patients were men with ages from 32 to 65 years (mean ± SD: 49.4 ± 9.5 years). Significant CAD was defined as having at least one epicardial vessel with ≥ 70% or left main>50% stenosis. All patients enrolled in this study underwent basic echocardiography, speckle tracking analysis, and coronary angiography. In 70 patients, PSS was calculated and myocardial perfusion imaging (MPI) was utilized as gold standards for the assessment of myocardial viability in patients with documented NSTEACS. The sensitivity, specificity, positive and negative predictive values of peak longitudinal systolic strain (2D-STE) and PSS were calculated. Left ventricular systolic strain was displayed as bull’s eye plot and territorial longitudinal strain (TLS) in the territory of the infarct-related artery. They were obtained within 24 hours from admission. Coronary angiography (CA) was performed within 24 hours from admission and used as a reference tests to assess the severity of CAD. Results: Echocardiogram obtained from the patients showed any no wall motion abnormalities at rest, although speckle tracking analysis was abnormal in 167 patients. In the first group of patients from the UAE, GLS showed a high sensitivity of 80% and a very high specificity of 93% for detection of significant CAD. In addition, PSS demonstrated a high sensitivity of 80% with an average specificity of 57%. The combination of GLS and PSS showed a further increase in sensitivity, specificity with positive and negative predictive values of 98%, 91%, 99% and 97%, respectively. Therefore, a very high correlation of GLS and PSS with coronary angiography was demonstrated: =0.90, p<0.0001 and R=0.88, p<0.0001, respectively. Furthermore, PSS showed a very high concordance with MPI scan (stress-rest-re injection studies) in detection of ischemic viable myocardium with very high sensitivity of 85%, r=0.79. In the Qatari (HHHMC) patients, a multi-vessel disease or left main disease (MV) was documented in 53.6%, and those with single vessel disease (SV) in 46.4%. LAD, circumflex and RCA lesions were found in 65, 50 and 39 patients, respectively. A control group of 129 cases was selected from outpatients referred to the echocardiography unit. The results showed that in comparison to CA, GLS sensitivity and specificity were 84% and 70%, respectively in all the patients. The sensitivity of GLS was 87% in MV and 80% in SV. Territorial strain sensitivity was 50%, 74% and 84.6% for the left anterior descending artery (LAD), circumflex and right coronary artery (RCA), respectively compared to specificity values of 64%, 65% and 61.7%, respectively. Conclusion: It is concluded that GLS by speckle tracking analysis is definitely an accurate method in early diagnosis of the severity of CAD in patients presenting with NSTE ACS. The combined use of GLS and PSS showed very high diagnostic accuracy for the identification of significant CAD in these patients. Strain imaging by STE may be applied to diagnose the severity of myocardial ischemia by showing reduction in peak systolic strain. Moreover, it is equally important to demonstrate post-systolic shortening which is a characteristic feature of ischemic viable myocardium after ACS requiring revascularization

Science Models as Value-Added Services for Scholarly Information Systems

The paper introduces scholarly Information Retrieval (IR) as a further dimension that should be considered in the science modeling debate. The IR use case is seen as a validation model of the adequacy of science models in representing and predicting structure and dynamics in science. Particular conceptualizations of scholarly activity and structures in science are used as value-added search services to improve retrieval quality: a co-word model depicting the cognitive structure of a field (used for query expansion), the Bradford law of information concentration, and a model of co-authorship networks (both used for re-ranking search results). An evaluation of the retrieval quality when science model driven services are used turned out that the models proposed actually provide beneficial effects to retrieval quality. From an IR perspective, the models studied are therefore verified as expressive conceptualizations of central phenomena in science. Thus, it could be shown that the IR perspective can significantly contribute to a better understanding of scholarly structures and activities.Comment: 26 pages, to appear in Scientometric

Brain immune cells undergo cGAS-STING-dependent apoptosis during herpes simplex virus type 1 infection

Protection of the brain from viral infections involves the type I interferon (IFN-I) system, defects in which renders humans susceptible to herpes simplex encephalitis (HSE). However, excessive cerebral IFN-I levels leads to pathologies, suggesting the need for tight regulation of responses. Based on data from mouse models, human HSE cases, and primary cell culture systems, we here show that microglia and other immune cells undergo apoptosis in the HSV-1-infected brain through a mechanism dependent on the cyclic GMP-AMP synthase (cGAS) - stimulator of interferon genes (STING) pathway, but independent of IFN-I. HSV-1 infection of microglia induced cGAS-dependent apoptosis at high viral doses, while lower viral doses led to IFN-I responses. Importantly, inhibition of caspase activity prevented microglial cell death and augmented IFN-I responses. Accordingly, HSV-1-infected organotypic brain slices, or mice treated with caspase inhibitor, exhibited lower viral load and improved outcome of infection. Collectively, we identify an activation-induced apoptosis program in brain immune cells which down-modulates local immune responses

Efficient Analysis of High Dimensional Data in Tensor Formats

In this article we introduce new methods for the analysis of high dimensional data in tensor formats, where the underling data come from the stochastic elliptic boundary value problem. After discretisation of the deterministic operator as well as the presented random fields via KLE and PCE, the obtained high dimensional operator can be approximated via sums of elementary tensors. This tensors representation can be effectively used for computing different values of interest, such as maximum norm, level sets and cumulative distribution function. The basic concept of the data analysis in high dimensions is discussed on tensors represented in the canonical format, however the approach can be easily used in other tensor formats. As an intermediate step we describe efficient iterative algorithms for computing the characteristic and sign functions as well as pointwise inverse in the canonical tensor format. Since during majority of algebraic operations as well as during iteration steps the representation rank grows up, we use lower-rank approximation and inexact recursive iteration schemes

Opposition and dissidence: two modes of resistance against international rule

Rule is commonly conceptualized with reference to the compliance it invokes. In this article, we propose a conception of rule via the practice of resistance instead. In contrast to liberal approaches, we stress the possibility of illegitimate rule, and, as opposed to critical approaches, the possibility of legitimate authority. In the international realm, forms of rule and the changes they undergo can thus be reconstructed in terms of the resistance they provoke. To this end, we distinguish between two types of resistance - opposition and dissidence - in order to demonstrate how resistance and rule imply each other. We draw on two case studies of resistance in and to international institutions to illustrate the relationship between rule and resistance and close with a discussion of the normative implications of such a conceptualization

Institutional legacies and HRM: similarities and differences in HRM practices in Portugal and Mozambique

This is a study of institutional change and continuity, comparing the trajectories followed by Mozambique and its formal colonial power Portugal in HRM, based on two surveys of firm level practices. The colonial power sought to extend the institutions of the metropole in the closing years of its rule, and despite all the adjustments and shocks that have accompanied Mozambique’s post-independence years, the country continues to retain institutional features and associated practices from the past. This suggests that there is a post-colonial impact on human resource management. The implications for HRM theory are that ambitious attempts at institutional substitution may have less dramatic effects than is commonly assumed. Indeed, we encountered remarkable similarities between the two countries in HRM practices, implying that features of supposedly fluid or less mature institutional frameworks (whether in Africa or the Mediterranean world) may be sustained for protracted periods of time, pressures to reform notwithstanding. This highlights the complexities of continuities which transcend formal rules; as post-colonial theories alert us, informal conventions and embedded discourse may result in the persistence of informal power and subordination, despite political and legal changes

Siderophore-Mediated Zinc Acquisition Enhances Enterobacterial Colonization of the Inflamed Gut

Zinc is an essential cofactor for bacterial metabolism, and many Enterobacteriaceae express the zinc transporters ZnuABC and ZupT to acquire this metal in the host. However, the probiotic bacterium Escherichia coli Nissle 1917 (or “Nissle”) exhibits appreciable growth in zinc-limited media even when these transporters are deleted. Here, we show that Nissle utilizes the siderophore yersiniabactin as a zincophore, enabling Nissle to grow in zinc-limited media, to tolerate calprotectin-mediated zinc sequestration, and to thrive in the inflamed gut. We also show that yersiniabactin’s affinity for iron or zinc changes in a pH-dependent manner, with increased relative zinc binding as the pH increases. Thus, our results indicate that siderophore metal affinity can be influenced by the local environment and reveal a mechanism of zinc acquisition available to commensal and pathogenic Enterobacteriaceae