Advances in Electrocardiograms

Electrocardiograms have become one of the most important, and widely used medical tools for diagnosing diseases such as cardiac arrhythmias, conduction disorders, electrolyte imbalances, hypertension, coronary artery disease and myocardial infarction. This book reviews recent advancements in electrocardiography. The four sections of this volume, Cardiac Arrhythmias, Myocardial Infarction, Autonomic Dysregulation and Cardiotoxicology, provide comprehensive reviews of advancements in the clinical applications of electrocardiograms. This book is replete with diagrams, recordings, flow diagrams and algorithms which demonstrate the possible future direction for applying electrocardiography to evaluating the development and progression of cardiac diseases. The chapters in this book describe a number of unique features of electrocardiograms in adult and pediatric patient populations with predilections for cardiac arrhythmias and other electrical abnormalities associated with hypertension, coronary artery disease, myocardial infarction, sleep apnea syndromes, pericarditides, cardiomyopathies and cardiotoxicities, as well as innovative interpretations of electrocardiograms during exercise testing and electrical pacing

Toward a Grammar of the Blogosphere: Rhetoric and Attention in the Networked Imaginary

This dissertation explores the rhetorical imaginary of internetworked societies by examining three cases where actors in the blogosphere shaped public deliberation. In each case, I analyze a trope that emerged organically as bloggers theorized their own rhetorical interventions, and argue that these tropes signal shifts in how citizens of networked societies imagine their relations. The first case study, on the blogosphere's reaction to Trent Lott's 2002 toast to Strom Thurmond, examines how bloggers "flooded the zone" by relentlessly interpreting the event and finding evidence that eventually turned the tide of public opinion against Lott. Flooding the zone signifies the inventional possibilities of blogging through the production of copious public argument. The second case study, focusing on the 2003 blogging of the Salam Pax, an English-speaking Iraqi living in Iraq on the precipice of war, develops the idea of "ambient intimacy" which is produced through the affective economy of blogging. The ambient intimacy produced through blogging illustrates the blurring of traditional public/private distinctions in contemporary public culture. The third case study, on the group science blog RealClimate, identifies how blogs have become sites for translating scientific controversies into ordinary language through a process of "shallow quotation." The diffusion of expertise enabled by the interactive format of blogging provides new avenues to close the gap between public and technical reasoning. The dissertation concludes by examining the advent and implications of "hyperpublicity" produced by ubiquitous recording devices and digital modes of circulation

Identification and characterisation of the post-translational modifications that regulate the Hypoxia Inducible Factors, HIF-1α and HIF-2α.

Eukaryotic organisms, including human, require molecular oxygen (O2) to survive. During periods of low O2 availability (hypoxia), a family of protein transcription factors become stabilised (Hypoxia Inducible Factors, HIF) and allow the adaption to hypoxia by regulating gene expression. Hypoxic adaption is required for cellular survival and is considered a hallmark of cancer. HIF is a heterodimeric protein consisting of a stable beta subunit (HIF1β) and an O2 labile alpha subunits (HIF-1α or HIF-2α). The two HIFα isoforms share ~50% sequence homology, yet have different target genes, O2 sensitivity and sub-nuclear localisation. The O2-dependent stability of HIFα subunits is due to an O2 dependent, proline hydroxylation post translational modification (PTM) resulting in degradation. The current understanding of post-translational regulation beyond the O2 dependent hydroxylation are poorly understood. Previous published studies aiming to identify HIF PTMs did it using a targeted/biased approach and failed to compare isoforms. Therefore, the primary aim of this work was to expand the understanding of the regulatory network of HIFα proteins, by obtaining an unbiased identification of PTMs and binding partners using a proteomics approach. We have performed an in-depth analysis of PTMs across ~90% of the total protein sequence for HIF-1α and HIF-2α in response to hypoxia, with a specific focus on phosphorylation. In total, ~50 different PTMs were confidently identified (~25 of which were phosphorylation) for each HIFα proteins, with the majority of these PTM sites being novel. Identified PTM sites were investigated through a combination of hypoxia regulation, evolutionary analysis, domain localisation and crystal structure modelling to identify potentially interesting sites to prioritise functional characterisation. This led to the discovery of HIF-1α Serine 31 phosphorylation, a previously superficially investigated site, as a potentially important mechanism to fully abolish HIF-1α-mediated transcription by preventing its binding to DNA. In addition, HIFα binding partners in response to hypoxia were identified. We demonstrated that many more proteins interact with HIFα proteins than currently known. The binding partner profiles were hypoxia-dependent, especially for HIF-2α which had >10 fold more binding partners confidently identified in hypoxia than normoxia. Combined with Gene ontology (GO) analysis, the binding partners identified strongly suggest a role for HIFα with mitochondria. Whilst we have discovered many novel data, this project has opened many avenues for further investigation. Overall, it is clear that the current understanding of HIF mediated hypoxia signalling is incomplete, and that the signalling pathways at play are orders of magnitude more complex than the current understandin

2022, UMaine News Press Releases

This is a catalog of press releases put out by the University of Maine Division of Marketing and Communications between January 3, 2022 and October 17, 2022