Imaging of metabolism and autonomic innervation of the heart by positron emission tomography

Positron emission tomography (PET) allows, in combination with multiple radiopharmaceuticals, unique physiological and biochemical tissue characterization. Tracers of blood flow, metabolism and neuronal function have been employed with this technique for research application. More recently, PET has emerged in cardiology as a useful tool for the detection of coronary artery disease and the evaluation of tissue viability. Metabolic tracers such as fluorine-18 deoxyglucose (FDG) permit the specific delineation of ischaemically compromised myocardium. Clinical studies have indicated that the metabolic imaging is helpful in selecting patients for coronary artery bypass surgery or coronary angioplasty. More recent research work has concentrated on the use of carbon-11 acetate as a marker of myocardial oxygen consumption. Together with measurements of left ventricular performance, estimates of cardiac efficiency can be derived from dynamic 11 C-acetate studies. The non-invasive evaluation of the autonomic nervous system of the heart was limited in the past. With the introduction of radiopharmaceuticals which specifically bind to neuronal structures, the regional integrity of the autonomic nervous system of the heart can be evaluated with PET. Numerous tracers for pre- and postsynaptic binding sites have been synthesized. 11 C-hydroxyephedrine represents a new catecholamine analogue which is stored in cardiac presynaptic sympathetic nerve terminals. Initial clinical studies with it suggest a promising role for PET in the study of the sympathetic nervous system in various cardiac diseases such as cardiomyopathy, ischaemic heart disease and diabetes mellitus. The specificity of the radiopharmaceuticals and the quantitative measurements of tissue tracer distribution provided by PET make this technology a very attractive research tool in the cardiovascular sciences with great promise in the area of cardiac metabolism and neurocardiology.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/46833/1/259_2004_Article_BF00177375.pd

Dynamique de réaction des anions Dichlorocarbène au moyen d'un spectromètre de masse à double focalisation.

peer reviewedThe dissociation dynamics of CCl2- anions were studied under various internal energy conditions. This study involved the measurement of daughter-ion spectra and branching ratios and of the amount of kinetic energy released (KER) on the fragments. The competition between C and Cl loss for CCl2- ions created by many of the following sequence of processes: CCl4->CCl2+->(G=Xe, Kr C6H6)->CCl2--> fragments (1); CCl4->(CCl2--+[Cl,Cl]+;CCl2-; CCl2- (Ne)-> Fragments (2); CCl4->(CCl2)2+ (C6H6)->CCl2--> fragments (3) was particularly investigated. For process (1), the amount of fragmentating CCl2- ions is 8-10 times larger with Kr than with Xe or C6H6. The KER for Cl loss is smaller than 0.20 eV with the three target gases used. For the loss of C, the KER is much larger (0.7 eV). This KER is, however, equal to 0.21 eV for the collisionally activated C loss in process (2). For this latter process, the C loss vs Cl loss branching ratio decreases with increasing internal energy. The KERs measured for process (3) are vary similar to those obtained for process (1). It is suggested that repulsive or slightly bound excited states which correlate directly to the Cl2-(X2Sigma+)+C asymptote and which are vibronically coupled to the ground state play an important role in these dissociation processes

Guide de la récupération du déchet-matériau bois au niveau local: Des clés pour aiguiller les projets intégrant un volet récup’ dans leurs pratiques

info:eu-repo/semantics/publishe

Policy brief: Projet Wood in Molenbeek

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Effect of cardiac resynchronization therapy on functional mitral regurgitation in heart failure.

Cardiac resynchronization therapy (CRT) reduces functional mitral regurgitation (MR) at rest. This study assessed exercise-induced changes in MR in patients with heart failure who were helped by CRT. The determinants of these exercise-induced changes in MR were analyzed in asynchronous and resynchronized left ventricles

Identification of cardiac repercussions after intense and prolonged concentric isokinetic exercise in young sedentary people

INTRODUCTION: Cardiopathies are the world's leading cause of mortality and morbidity. Although rare, cardiovascular accidents can occur during intense and infrequent sporting activity, particularly among those who are unaware of their heart condition. The development of cardiospecific biochemical markers has led to a reconsideration of the role of biology in the diagnosis of cardiovascular illnesses. The aim of this study therefore was, through the use of cardiac biomarker assays, to highlight the impact of sustained physical effort in the form of intense and prolonged concentric isokinetic exercise and to research potential cardiovascular risks. MATERIALS AND METHODS: Eighteen subjects participated in a maximal concentric isokinetic exercise involving 30 knee flexion-extensions for each leg. Five blood tests were taken to study the kinetics of the cardiac biomarkers. Haemodynamic parameters were measured continuously using a Portapres, and respiratory parameters were measured using a Sensormedics Vmax 29C. RESULTS: The results showed significant increases in the creatine kinase, myoglobin, homocysteine and haemoglobin cardiac markers. Evolutionary trends were also observed for the following biomarkers: NT-proBNP, myeloperoxydase and C-reactive protein. All the physiological parameters measured presented statistically significant changes. CONCLUSION: Isokinetic effort leads to the release of cardiac markers in the blood, but these do not exceed the reference values in healthy subjects. Maximal concentric isokinetic exercise does not, therefore, lead to an increased risk of cardiovascular pathologies