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Coronary physiology

Wilfried Dinh, Barbara Albrecht-Küpper, Mihai Gheorghiade, Adriaan A Voors, Michael van der Laan, Hani N Sabbah
Adenosine exerts a variety of physiological effects by binding to cell surface G-protein-coupled receptor subtypes, namely, A1, A2a, A2b, and A3. The central physiological role of adenosine is to preclude tissue injury and promote repair in response to stress. In the heart, adenosine acts as a cytoprotective modulator, linking cardiac function to metabolic demand predominantly via activation of adenosine A1 receptors (A1Rs), which leads to inhibition of adenylate cyclase activity, modulation of protein kinase C, and opening of ATP-sensitive potassium channels...
October 22, 2016: Handbook of Experimental Pharmacology
Walter H Reinhart
The hematocrit (Hct) determines the oxygen carrying capacity of blood, but also increases blood viscosity and thus flow resistance. From this dual role the concept of an optimum Hct for tissue oxygenation has been derived. Viscometric studies using the ratio Hct/blood viscosity at high shear rate showed an optimum Hct of 50-60% for red blood cell (RBC) suspensions in plasma. For the perfusion of an artificial microvascular network with 5-70μm channels the optimum Hct was 60-70% for high driving pressures. With lower shear rates or driving pressures the optimum Hct shifted towards lower values...
October 21, 2016: Clinical Hemorheology and Microcirculation
Joseph M Blankush, Robbie Freeman, Joy McIlvaine, Trung Tran, Stephen Nassani, I Michael Leitman
Modified Early Warning Scores (MEWS) provide real-time vital sign (VS) trending and reduce ICU admissions in post-operative patients. These early warning calculations classically incorporate oxygen saturation, heart rate, respiratory rate, systolic blood pressure, and temperature but have not previously included end-tidal CO2 (EtCO2), more recently identified as an independent predictor of critical illness. These systems may be subject to failure when physiologic data is incorrectly measured, leading to false alarms and increased workload...
October 20, 2016: Journal of Clinical Monitoring and Computing
Shazia T Hussain, Geraint Morton, Kalpa De Silva, Roy Jogiya, Andreas Schuster, Matthias Paul, Divaka Perera, Eike Nagel
AIMS: This study assesses the relationship between classical anatomical jeopardy scores, functional jeopardy scores (combined anatomical and haemodynamic data), and the extent of ischaemia identified on cardiovascular magnetic resonance (CMR) perfusion imaging. METHODS AND RESULTS: In 42 patients with stable angina and suspected coronary artery disease (CAD), CMR perfusion imaging was performed. Fractional Flow Reserve (FFR) was measured in vessels with ≥50 % stenosis...
October 20, 2016: Clinical Research in Cardiology: Official Journal of the German Cardiac Society
Lois Choy, Jie Ming Yeo, Vivian Tse, Shing Po Chan, Gary Tse
The mouse is the second mammalian species, after the human, in which substantial amount of the genomic information has been analyzed. With advances in transgenic technology, mutagenesis is now much easier to carry out in mice. Consequently, an increasing number of transgenic mouse systems have been generated for the study of cardiac arrhythmias in ion channelopathies and cardiomyopathies. Mouse hearts are also amenable to physical manipulation such as coronary artery ligation and transverse aortic constriction to induce heart failure, radiofrequency ablation of the AV node to model complete AV block and even implantation of a miniature pacemaker to induce cardiac dyssynchrony...
September 2016: IJC Heart & Vasculature
Donghoon Choi
: Atherosclerotic renal artery stenosis is an increasingly recognized medical problem especially in elderly patients. It commonly occurs with systemic manifestations including hypertension (HTN), chronic kidney disease (CKD) or atherosclerotic diseases including coronary or peripheral artery disease. Significant renal artery stenosis may result in HTN, ischemic nephropathy, however it is still in debate about the benefit of revascularization. Although several randomized controlled trials including Angioplasty and Stenting for Renal Artery Lesions (ASTRAL) and Cardiovascular Outcomes in Renal Atherosclerotic Lesions (CORAL) study has failed to reveal a significant benefit of angioplasty, angioplasty with medical therapy is increasingly accepted in some patients with certain clinical conditions...
September 2016: Journal of Hypertension
Karima Ait-Aissa, Joseph Hockenberry, David Gutterman, Aron Geurts, Andreas Beyer
OBJECTIVE: Flow mediated dilation (FMD) is the most physiological relevant form of endothelial-mediated vasodilation. Our laboratory has previously shown that telomerase, a ribo-nucleoprotein that counteracts telomere shortening, has a protective effect on endothelial function under conditions of oxidative stress in the human microcirculation. In the presence of coronary artery disease, decreased telomerase activity contributes to a shift in the mediator of FMD from atheroprotective nitric oxide (NO) to pro-inflammatory and atherogenic hydrogen peroxide (H2O2)...
September 2016: Journal of Hypertension
Masatsugu Horiuchi
Hypertensive patients have greater chances of such cardiovascular events as stroke, coronary heart disease, heart or renal failure, peripheral artery disease, and dementia. It is also well recognized that diabetes increases the cardiovascular risks in concert with hypertension. Therefore, main goals for an innovation of anti-hypertensive therapy would be to achieve further risk reduction by targeting the functional, metabolic, and structural alterations associated with hypertension. Professors Dzau and Braunwald et al proposed the concept of "the cardiovascular disease continuum" in 1991, and that hypertension may trigger the chain of events, leading to end-stage heart disease; however, this concept was quite new at that time, and there was some discussion whether "the cardiovascular disease continuum" is true or not...
September 2016: Journal of Hypertension
Stephen Harrap
Genetic discovery in blood pressure is generally referenced in relation to protein-coding genes, despite the fact that genes less than 2% of the genome. Recent exploration of the DNA sequences between genes, once called "junk" DNA, has revealed a wealth of transcripts for RNA species that do not encode protein. These non-coding RNAs (ncRNAs) have emerged as dynamic managers of the business of the genome, able to coordinate the expression of genes in time and space to achieve the complexities of normal development and growth...
September 2016: Journal of Hypertension
E D'Elia, P Ferrero, C Vittori, A Calabrese, V Duino, S Perlini, M Senni
Athletes may have electrocardiogram (ECG) repolarization abnormalities during stress test suggestive for ischemia in the absence of ischemic coronary artery disease, often in a setting of myocardial septum hypertrophy. Global longitudinal strain (GLS) might be altered in these athletes compared to hypertensive patients with the same degree of septal thickness. About 735 consecutive athletes were screened for mandatory assessment of fitness to participate in competitive sports. At the stress test, 23 (19 M, 4 F) were found to have ECG repolarization abnormalities suggestive for ischemia in the presence of normal coronary vessels...
October 17, 2016: Scandinavian Journal of Medicine & Science in Sports
Omer Akyol, Sumeyya Akyol, Chu-Huang Chen
Endothelial cells (EC) respond to injury by releasing numerous factors, including von Willebrand factor (VWF). High circulating levels of unusually large VWF multimers (UL-VWFM) have strong procoagulant activity and facilitate platelet adhesion and aggregation by interacting with platelets after an acute event superimposed on peripheral arterial disease and coronary artery disease. ADAMTS13-a disintegrin-like metalloproteinase with thrombospondin motif type 1 member 13-regulates a key physiological process of coagulation in the circulation by cleaving VWF multimers into small, inactive fragments...
October 13, 2016: Clinica Chimica Acta; International Journal of Clinical Chemistry
Michinobu Nagao, Yuzo Yamasaki, Takeshi Kamitani, Satoshi Kawanami, Masatoshi Kondo, Hiromichi Sonoda, Taisuke Fujioka, Hiroshi Honda
The purpose of this study is to analyze the geometrical characteristics of aortic root and left ventricular (LV) function in aortic stenosis (AS) using 256-slice coronary-computed tomography angiography (CCTA). Retrospective ECG-gated 256-slice CCTA data from 32 patients with tricuspid AS scheduled for aortic valve replacement, and 11 controls were analyzed. Aortic root geometry was measured using multiplanar reconstruction CT images. CCTA data set was transformed into 100 phases/cycle using motion coherence image processing...
October 13, 2016: Heart and Vessels
Jin-Jin Lu, Bing-Jie Jia, Lin Yang, Wen Zhang, Xin Dong, Ping Li, Jun Chen
It has been proved that the purine metabolic pathway has been implicated in various biological disorders including gout, diabetes, coronary heart diseases, and neurodegenerative diseases. The analysis of the purine metabolic pathway in organisms reveals important alterations under different physiological and pathological conditions, which contributes to the pathological study, diagnosis, and therapy of related diseases. In the present study, an ultra-high performance liquid chromatography with ultraviolet and tandem mass spectrometry (UHPLC-UV-MS/MS) method was developed for conducting the comprehensive analysis of the metabolite profiles of the purine pathway in rat plasma through a single analysis...
September 28, 2016: Journal of Chromatography. B, Analytical Technologies in the Biomedical and Life Sciences
Michael Bennardo, Faisal J Alibhai, Elena V Tsimakouridze, Nirmala Chinnappareddy, Peter Podobed, Cristine J Reitz, W Glen Pyle, Jeremy A Simpson, Tami A Martino
Diurnal or circadian rhythms are fundamentally important for healthy cardiovascular physiology, and play a role in timing of onset and tolerance to myocardial infarction (MI) in patients. Whether time of day of MI triggers different molecular and cellular responses that can influence myocardial remodelling is not known. This study was designed to test whether time of day of MI triggers different gene expression, humoral, and innate inflammatory responses that contribute to cardiac repair after MI. Mice were infarcted by left anterior descending coronary artery ligation (MI model) within a 2 hour time window either shortly after lights on or lights off, and the early remodelling responses at 8 hours post infarction were examined...
October 12, 2016: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology
Giuseppe Tarantini, Francesco Saia, Piera Capranzano, Bernardo Cortese, Marco Mojoli, Giacomo Boccuzzi, Andrea Cuculo, Salvatore Geraci, Alessio Mattesini, Jacopo Oreglia, Francesco Summaria, Luca Testa, Sergio Berti, Giovanni Esposito, Alessio La Manna, Ugo Limbruno, Alfredo Marchese, Ciro Mauro, Fabio Tarantino, Alessandro Salvi, Gennaro Santoro, Ferdinando Varbella, Roberto Violini, Giuseppe Musumeci
Drug-eluting stents (DES) are the current gold standard for percutaneous treatment of coronary artery disease. However, DES are associated with a non-negligible risk of long-term adverse events related to persistence of foreign material in the coronary artery wall. In addition, DES implantation causes permanent caging of the native vessel, thus impairing normal vasomotricity and the possibility of using non-invasive coronary imaging or preforming subsequent bypass surgery. On the contrary, coronary bioresorbable stents (BRS) may provide temporary mechanical support to coronary wall without compromising the subsequent recovery of normal vascular physiology, and have the potential to prevent late adverse events related to permanent elements...
October 2016: Giornale Italiano di Cardiologia
Giuseppe Sangiorgi, Riccardo Colantonio, Gabriele Antonini, Antonio Savino, Massimiliano Sperandio
Erectile dysfunction (ED) is defined as the inability to get and maintain a sufficient erection to ensure an acceptable sexual activity for the subject and the partner. Although ED does not represent per se a serious disease, it carries a notable and severe influence on quality of life, with significant implications on familiar and social relationship; DE may cause depression, shame, impairment of personal esteem and relational problems. Among many possible etiologies of ED, atherosclerotic disease of penile arteries represents one of the most frequent causes, so it should always be looked for in patients with multiple risk factors for cardiovascular disease or an established coronary or peripheral artery disease...
October 2016: Giornale Italiano di Cardiologia
Bin Yang, Ping Yan, Hui Gong, Lin Zuo, Ying Shi, Jian Guo, Rui Guo, Jun Xie, Bao Li
Myocyte apoptosis is a key determinant of cardiac recovery and prognosis of patients with acute myocardial infarction (AMI). Tumor necrosis factor (TNF)-like weak inducer of apoptosis (TWEAK), a member of TNF superfamily, is a pro-inflammatory and pro-angiogenic cytokine implicated in physiological tissue regeneration and wound repair and is closely related to cardiac remodeling, dysfunction and fibrosis. However, the role of TWEAK and its receptor Fn14 in the cardiomyocyte apoptosis is still poorly understood...
2016: American Journal of Translational Research
Kamil J Chodzyński, Simone Gremmo, Omer F Eker, Jacques Lalmand, Adel Aminian, Daniel Ribeiro de Sousa, Karim Zouaoui Boudjeltia, Grégory Coussement
BACKGROUND: Since hemodynamics plays a key role in the development and evolution of cardiovascular pathologies, physician's decision must be based on proper monitoring of relevant physiological flow quantities. METHODS: A numerical analysis of the error introduced by an intravascular Doppler guide wire on the peak velocity measurements has been carried out. The effect of probe misalignment (±10°) with respect to the vessel axis was investigated. Numerical simulations were performed on a realistic 3D geometry, reconstructed from coronary angiography images...
October 10, 2016: Biomedical Engineering Online
Anthony T Gerlach, Danielle M Blais, G Morgan Jones, Pamela K Burcham, Stanislaw P Stawicki, Charles H Cook, Claire V Murphy
BACKGROUND: Dexmedetomidine is commonly used for sedation in the Intensive Care Unit (ICU), and its use may be associated with hypotension. We sought to determine predictors of dexmedetomidine-associated hypotension. METHODS: Retrospective, single-center study of 283 ICU patients in four adults ICUs over a 12 month period. Univariate analyses were performed to determine factors associated with dexmedetomidine-related hypotension. Risk factors significant at the 0...
July 2016: International Journal of Critical Illness and Injury Science
Masashi Tawa, Tomio Okamura
Coronary artery disease is associated with oxidative stress due to the excessive generation of free radicals in the vascular wall. This study investigated the impact of tert-butyl hydroperoxide (t-BuOOH), a peroxyl radical generator, on the redox state of soluble guanylate cyclase (sGC) in isolated monkey coronary arteries. Helically cut strips of endothelium-intact monkey coronary arteries treated with the nitric oxide synthase inhibitor N(G)-nitro-L-arginine (10 μmol/L) were exposed for approximately 60 min to either no drug or t-BuOOH (100 μmol/L) in the presence and absence of α-tocopherol (300 μmol/L)...
October 2016: Pharmacology Research & Perspectives
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