277 research outputs found
Clinical meaning of intermittent left bundle branch block and T-wave alterations (in normally conduced beats) in subjects with no sign of cardiopathy
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Stunned and hibernating myocardium: possibility of intervention.
No full textThere are several potential outcomes of myocardial ischemia. When ischemia is severe and prolonged, irreversible damage occurs and there is no recovery of contractile function. When myocardial ischemia is less severe but still prolonged, myocytes may remain viable but exhibit depressed contractile function. Under these conditions, reperfusion restores complete contractile performance. This type of ischemia, leading to a reversible, chronic left ventricular dysfunction, has been termed hibernating myocardium. The difference between this condition and that described before, i.e., prolonged ischemia, which results in further damage on reperfusion, is, most likely, related to residual coronary flow. In the hibernating myocardium, which is always supplied by a narrow coronary artery, blood flow is not low enough to cause progression toward tissue necrosis, but it is low enough to cause pH changes that, in turn, are responsible for the downregulation of myocardial contractility. The level of underperfusion is sufficient to maintain aerobic metabolism of the quiescient myocardium as demonstrated by the absence of lactate and creatine phosphokinase release. There are no doubts that revascularization is essential for hibernated myocardium, and the clinical goal to achieve is the possibility of accurately distinguishing viable from infarcted tissue. A third possible outcome of myocardial ischemia is a postischemic ventricular dysfunction or myocardial stunning. This term describes a transient mechanical dysfunction that persists on reperfusion after a short period of ischemia, despite the absence of irreversible damage. There are numerous clinical conditions in which stunning might manifest.(ABSTRACT TRUNCATED AT 250 WORDS
Canna tandilensis Ciciar. (Cannaceae-Zingiberales), a new species from Argentina.
No full textCanna tandilensis es el nombre que se propone para designar una especie nueva para la ciencia que crece en colonias silvestres densas, terrestres, en roquedales, siempre expuesta a la radiación solar. Sus individuos de tamaño pequeño a mediano producen inflorescencias reducidas y paucifloras. Las flores son grandes, con estaminodios angostos reflejos de color anaranjado brillante. Los labelos y estaminodios son conspicuos y presentan guías de néctar en forma de líneas gruesas amarillas sobre fondo anaranjado. El epíteto específico hace referencia a la ciudad de Tandil en el sur de la Provincia de Buenos Aires de donde procede el holotipo. Se presenta una descripción detallada de la especie y un estudio de caracteres vegetativos y florales, que se compararon con los de otras dos especies C. lineata y C. glauca. De acuerdo a estas nuevas evidencias se sugiere la presencia de dos grupos de especies afines en el género. El número de especies relevadas hasta el momento en Argentina es de 16.Canna tandilensis is proposed as a species new to science. Plants grow wild terrestrial, in rocky places exposed to solar radiation forming dense colonies whose individuals of small to medium length, produce reduced inflorescences with large and few yellow to bright orange flowers and narrow and reflexed staminodes. The specific epithet refers to the city of Tandil at the south of Buenos Aires Province where the holotype comes from. It is related to other species having reduced inflorescences, narrow leaves and staminodes, and nectar guides in androecium pieces such as C. lineata. A detailed description of the new species is given, along with a study of the morphological vegetative and floral characters. These characters were compared with those from two other species C. glauca and C. lineata. According to these new evidences two groups of similar species of the genus are suggested. The number of species surveyed until now in Argentina rises to sixteen
Echocardiography during infusion of dobutamine for identification of reversibly dysfunction in patients with chronic coronary artery disease.
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Le alterazioni dell’onda T nel blocco di branca sinistra intermittente, patogenesi e significato clinico
No full textEarly ultrastructural changes of articular cartilage and synovial membrane in experimental vitamin A induced osteoarthritis
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