Animal Models of Dyssynchrony

Cardiac resynchronization therapy (CRT) is an important therapy for patients with heart failure and conduction pathology, but the benefits are heterogeneous between patients and approximately a third of patients do not show signs of clinical or echocardiographic response. This calls for a better understanding of the underlying conduction disease and resynchronization. In this review, we discuss to what extent established and novel animal models can help to better understand the pathophysiology of dyssynchrony and the benefits of CRT

Power Relations, Preservation and Voice: Introducing the Special Issue on Writing Histories of Education with Autobiographical Materials

As an introduction to the Special Issue ‘Power relations, preservation and voice. Writing histories of education with autobiographical materials,’ this article reviews the state of the art of autobiographical work in history of education research. Moreover, it argues that although writing histories of education with autobiographical materials is not a ‘new’ phenomenon, incorporating yet unknown or overlooked sources can bring fresh insights and perspectives to the field. This arises from the potential of autobiographical materials to complement reigning understandings of the past with alternate narratives. Yet, this introduction also points to challenges in working with such materials – particularly when we consider their work in constructing, presenting and performing a particular self. In this introduction, we start by discussing the term ‘autobiographical materials’ and tracing the development of using these kinds of materials in research. We then go on to explore various theoretical and methodological issues around working with autobiographical materials, in relation to production, preservation, access and the intellectual frameworks that we as researchers choose to employ. Finally, we introduce the articles that comprise this Special Issue. As a whole, this Issue offers a careful and considered re-visitation of the challenges and potentials inherent to working with autobiographical materials, further enriching the ongoing debate over power relations, preservation and voice when writing histories of education

A review of scientific research trends within ASPA No. 126 Byers Peninsula, South Shetland Islands, Antarctica

Byers Peninsula, Livingston Island, was one of the first sites in Antarctica designated for environmental conservation and scientific protection. Research on Byers Peninsula has been predominantly international, with 88 indexed publications (93% of them published during last 20 years) from 209 authors affiliated to 110 institutions from 22 nations, all of which are signatories to the Antarctic Treaty. Palaeontological research represented 20% of the published articles. The variety of freshwater bodies within the area has made Byers Peninsula a reference site for limnological studies (24% of papers). The site also contains numerous outcrops and periglacial features relevant to geology, stratigraphy and geomorphology (29%). Terrestrial biodiversity is extraordinarily high for lichens, bryophytes and invertebrates (15% of articles). Only 5% of the publications concern research on human activities, including both archaeology and impact monitoring. Glaciology, meteorology and climatology studies represent only 7% of papers. This work highlights the international and multidisciplinary nature of science conducted on Byers Peninsula in order to promote international cooperation and to provide information relevant for environmental management and conservation

Beta-1 adrenergic receptor signalling during early and late hypertensive cardiac remodelling

Abstract Funding Acknowledgements Type of funding sources: Foundation. Main funding source(s): BioTechMed Graz Objective Chronic activation of β1-adrenergic receptors (β1AR) in response to hypertension is consistently linked to maladaptive remodelling in the heart, however, the underlying mechanisms are not well understood. Here, our aim was to determine the subcellular profile and extent of β1AR expression at baseline and upon acute β-adrenergic stimulation in cardiac myocytes during early- and late-stage cardiac remodelling due to systemic hypertension. Methods Male Dahl salt-sensitive rats were fed a high-salt diet (HSD; 8% NaCl) for either five or ten weeks to induce early or late hypertensive cardiac remodelling, respectively. Age-, sex- and weight-matched Dahl salt-sensitive rats on a low-salt diet (LSD; 0.3% NaCl) served as controls. To test the effect of conventional anti-hypertensive treatment, a subset of HSD-fed animals received daily doses of the angiotensin-converting-enzyme-inhibitor Imidapril (ACE-I; 1mg/kg/day) starting two weeks after the feeding protocol was switched to HSD. Isolated ventricular myocytes were stimulated either under control conditions or in the presence of β-adrenergic agonist isoprenaline (ISO; 100nM; 1h). Confocal imaging of single cardiomyocytes allowed detailed quantification of β1AR in different cellular compartments. Finally, immunoblotting and microarray analyses were applied to quantify β1AR in the left ventricles of the corresponding groups of animals. Results In control rats, β1AR was found in a striated pattern throughout the cell typical for T-tubular network and in the perinuclear regions, while its expression significantly dropped upon ISO treatment. During early remodelling, basal β1AR expression was unchanged, but increased on the T-tubules and perinuclear regions upon acute stimulation with ISO. In contrast, late remodelling was marked by reduced β1AR expression at baseline, and significantly blunted increase in response to ISO compared to early time point. Interestingly, daily ACE-I treatment resulted in even more adverse phenotype as compared to untreated HSD-fed rats in early remodelling, but favourable control-like characteristics at late remodelling stage. Immunoblotting and microarrays from left ventricular tissue confirmed the data, where applicable. Conclusion Taken together, we showed that early hypertensive remodelling is marked by altered β1AR responsiveness upon β-adrenergic stimulation, whereas late remodelling also exhibits altered β1AR expression. ACE-I treatment seemed to interfere with early adaptive mechanisms, thereby worsening the phenotype as compared to untreated HSD-fed animals. However, upon prolonged application, it showed a clear protective effect from pathological molecular alterations at late remodelling. Further experiments involving downstream targets of β1AR signalling are required to fully understand the molecular sequence of events leading to early and late alterations in molecular composition of cardiomyocytes in the hypertensive heart. </jats:sec