1,721,024 research outputs found
[A multimedia echocardiographic archive]
No full textThe widespread diffusion of echocardiography requires to rationalize clinical examination archives; the recent improvement in computer processing speed and the addition of image processing capabilities on standard personal computer by using multimedia technology provide a low-cost solution to improve video digital acquisition and base management. Furthermore, the diffusion of computer networks supports the possibility of sending images in digital format from a work station to another. In this study we describe the setting-up of a system for echocardiographic image acquisition, storage, base management and analysis based on a standard multimedia Macintosh personal computer using readily available not-dedicated software. We tested the overall efficiency of this system in terms of time required to perform hardware and software procedures, storage capacity of the archive and possibility to exchange information with other wire-linked computer work-stations or via modem. This system has proven to require an acceptable time to perform all the procedures showing a high level of connectivity with other standard personal computer work-stations; however, some limitations with regard to time required in sending via modem long movie files need to be pointed out. In conclusion, in our experience new multimedia personal computer could offer to every physician with a minimum informatic knowledge the well known advantages of digital-video, at a reasonable cost
Targeting hypertensive myocardial fibrosis
No full textIn normal myocardium, myocytes represent only one-third of all cells, with the remaining two-thirds including fibroblasts and small cellular populations. While several weeks post partum the myocyte count stops increasing, the connective tissue cell count does not. In the early phases of arterial hypertension, adaptive left ventricular (LV) hypertrophy (LVH) is characterised by the growth of cardiac myocytes, which may or may not be accompanied by other alterations in tissue structure. In hypertensive heart disease, however, complex changes in myocardial composition occur, with a disproportionate involvement of noncardiomyocyte cells accounting for a pathological remodelling of tissue structure (pathological hypertrophy). Myocardial fibrosis is the result of both haemodynamic and nonhaemodynamic factors playing a synergistic role and reflects the loss of the physiological reciprocal regulation between stimulatory and inhibitory factors acting on the turnover of fibrillar collagen. Cardiac biopsy is the gold standard for assessing myocardial fibrosis; in the last decades different non-invasive approaches have been developed and validated to detect and follow-up cardiac fibrosis, including biochemical markers of collagen synthesis and degradation, cardiac hormones and ultrasonographic procedures. Due to the clinical implications of myocardial fibrosis and pathological LVH, it is of great interest to ascertain the effect of antihypertensive agents on cardiac structure: the optimal treatment of hypertensive patients should target a parallel decrease in cardiac mass and fibrosis. Preliminary evidence suggests that not all antihypertensive drugs affect fibrosis to the same extent: angiotensin-converting enzyme inhibitors and angiotensin II receptor blockers (ARBs) appear particularly effective, in contrast to β-blockers and diuretics. Finally, the impact of fibrosis and its regression on subsequent cardiovascular events when compared with LV mass and its reduction remain to be investigated
Validazione istologica della tecnica di caratterizzazione tissutale ultrasonica delle lesioni aterosclerotiche.
No full text
Experimental animal models of myocardinal damage in regenerative medicine studies involving adult bone marrow derived stem cells: ethical and methodological implication
No full textCardiac performance after myocardial infarction is compromised by ventricular remodeling, which represents a major cause of late infarct-related chronic heart failure and death. In recent years, the scientists' interest has focused on the hypothesis that the administration of bone marrow progenitors, following myocardial infarction, could ameliorate left ventricular remodeling by continuing to differentiate along the haematopoietic lineage. This approach has been developed minding to the consolidated use of transfusions to restore lost or depleted blood components and, therefore, as an enriched dose of various progenitors, generally autologous, injected peripherally or directly in the infarcted area. Since the safety of this therapy was not yet established, for ethical reasons pioneering researchers involved in these studies used animal models as surrogate of the human biologic system. Herein this hypothesis of therapy resulted in an increased use of living animals and in the reappraisal of models of myocardial damage with limited discussion on the theoretical basis of animal models applied to cell-based therapies. Recently, the European Union and its commission for surveillance of laboratory animals advanced a new proposal to restrict the use of living animals. This review will focus on the history of models utilization in biomedicine, with particular attention to animal models, and delineate an operative comparison between the two best known models of myocardial injury, namely coronary ligation and cryodamage, in the perspective of adult stem cell research applied to cardiovascular regenerative medicine
Coronary blood flow and myocardial ischaemia in hypertension
Full text linkThe aim of this investigation was to study the coronary pressure-flow relationship in 60 patients with chronic arterial hypertension of diverse aetiologies and in 14 normotensive subjects (control group). The hypertensive cohort included 6 patients with isolated systolic hypertension (ISH), 7 renovascular hypertensive patients with abnormally elevated angiotensin II plasma levels but without electrocardiographic and/or echocardiographic evidence of left ventricular hypertrophy (LVH) and 47 subjects with essential hypertension (EH), 21 of whom had LVH by electrocardiogram and/or echocardiogram. In the hypertensive cohort a Frank-Starling-like curve was found to describe the coronary pressure-flow relationship when the baseline values for coronary sinus blood flow (CBF, intravascular Doppler technique) were plotted against mean aortic pressure (intra-arterial blood pressure). In particular, the descending limb of such a curve represented a critical region where CBF was "inappropriately" low with respect to perfusion pressure. It was thus concluded that this inability of the heart to adapt CBF to its needs might account for the higher propensity to develop myocardial ischaemia encountered in severe essential hypertensive subjects with concomitant LVH and renovascular hypertensive patients
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