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Coronary Vasculature (coronary + vasculature)
Selected AbstractsLipoprotein(a) Is Related to the Extent of Lesions in the Coronary Vasculature and to Unstable Coronary SyndromesCLINICAL CARDIOLOGY, Issue 12 2000B.Sc., John D. Zampoulakis M.D. Abstract Background: Lp(a) is a highly atherogenic particle with a prothrombotic effect. Until now its relation to the extent and severity of the atheromatic lesions had not been established by standard procedures. Hypothesis: This study examined the correlation of Lp(a) to the extent and severity of coronary artery disease (CAD) and its relation to unstable clinical events (not including sudden death). Methods: In 202 patients undergoing coronary angiography, plasma lipids were measured with the usual procedures and Lp(a) with the enzyme-linked immunosorbent assay. The extent of CAD was expressed in the number of diseased vessels and its severity in terms of the severity coefficient and the obstruction coefficient. Results: A very strong relationship between LP(a) and the number of diseased vessels (p = 0.0007) signifying diffuse atherosclerosis, but no relation with the severity of the lesions, was found. However, it was the only lipid that correlated significantly with the number of totally occluded vessels (p = 0.0003). The thrombogenic ability of Lp(a) was manifested by increased incidence of myocardial infarction and unstable angina episodes in patients with elevated Lp(a) (p = 0.0157). Conclusion: Elevated Lp(a) predisposes to the extent of CAD and total occlusions but not to the severity of lesions. Patients with increased Lp(a) levels and unstable angina are at increased danger of suffering myocardial infarction. Thus, Lp(a) may predispose to plaque destabilization and thrombosis of noncritical lesions. [source] Development of the proepicardium in Xenopus laevisDEVELOPMENTAL DYNAMICS, Issue 10 2008Maike Jahr Abstract The proepicardium (PE) is an embryonic progenitor cell population, which provides the epicardium, the majority of the cardiac interstitium, the coronary vasculature and possibly some cardiomyocytes. Recent studies have documented (1) the presence of bilaterally paired PE anlagen in several vertebrates, and (2) species-specific differences in the fate of the left and right PE anlagen. Here, we document PE development in Xenopus laevis (stages 37,46). The PE appears at stage 41 in the form of a cone-shaped accumulation of mesothelial cells covering the pericardial surface of the right horn of the sinus venosus. No such structure appears on the left sinus horn. At the end of stage 41, the tip of the PE establishes a firm contact with the developing ventricle. A secondary tissue bridge is established facilitating the transfer of PE cells to the heart. During stages 41,46, this tissue bridge is visible in vivo through the transparent body wall. Corresponding to the morphological data, the PE marker gene Tbx18 is expressed only on the right sinus horn suggesting a right-sided origin of the PE. Left,right lineage tracing has confirmed this idea. These results show that Xenopus PE development proceeds in a bilaterally asymmetric pattern as previously observed in chicks. We speculate that asymmetric PE development is controlled by signals from left,right signaling pathways and that the PE is an indicator for right-sidedness in Xenopus embryos. Xenopus might be a good model to uncover the role of left,right signaling pathways in the control of asymmetric PE development. Developmental Dynamics 237:3088,3096, 2008. © 2008 Wiley-Liss, Inc. [source] Platelet-derived growth factors in the developing avian heart and maturating coronary vasculatureDEVELOPMENTAL DYNAMICS, Issue 4 2005Nynke M.S. Abstract Platelet-derived growth factors (PDGFs) are important in embryonic development. To elucidate their role in avian heart and coronary development, we investigated protein expression patterns of PDGF-A, PDGF-B, and the receptors PDGFR-, and PDGFR-, using immunohistochemistry on sections of pro-epicardial quail,chicken chimeras of Hamburger and Hamilton (HH) 28,HH35. PDGF-A and PDGFR-, were expressed in the atrial septum, sinus venosus, and throughout the myocardium, with PDGFR-, retreating to the trabeculae at later stages. Additionally, PDGF-A and PDGFR-, were present in outflow tract cushion mesenchyme and myocardium, respectively. Small cardiac nerves and (sub)epicardial cells expressed PDGF-B and PDGFR-,. Furthermore, endothelial cells expressed PDGF-B, while vascular smooth muscle cells and interstitial epicardium-derived cells expressed PDGFR-,, indicating a role in coronary maturation. PDGF-B is also present in ventricular septal development, in the absence of any PDGFR. Epicardium-derived cells in the atrioventricular cushions expressed PDGFR-,. We conclude that all four proteins are involved in myocardial development, whereas PDGF-B and PDGFR-, are specifically important in coronary maturation. Developmental Dynamics 233:1579,1588, 2005. © 2005 Wiley-Liss, Inc. [source] Pharmacology of the Selective 5-HT1B/1D Agonist FrovatriptanHEADACHE, Issue 2002M.B. Comer BSc Objective.,To determine the pharmacological profile of frovatriptan. Background.,Frovatriptan is a new 5-HT1B/1D agonist developed for the treatment of migraine. Methods.,Pharmacological studies were performed using in vitro and in vivo techniques. Results.,Radioligand-binding studies showed that frovatriptan has a high affinity for 5-HT1B and 5-HT1D receptors, and moderate affinity for 5-HT1A, 5-HT1F, and 5-HT7 receptors. In vitro, frovatriptan acts as a potent full agonist at human cloned 5-HT1B and 5-HT1D receptors, and as a moderately potent full agonist at 5-HT7 receptors. Studies of frovatriptan in isolated human arteries demonstrated a lower threshold for constriction of cerebral than coronary vasculature and a bell-shaped dose-response curve was apparent in the coronary arteries. In anesthetized dogs, frovatriptan administration produced no measurable effect on cardiac function or on blood pressure. Frovatriptan had no effects on coronary blood flow following transient coronary artery occlusion, whereas sumatriptan produced a prolonged and significant decrease in coronary blood flow. Conclusion.,The pharmacology of frovatriptan suggests that it should be an effective agent for the acute treatment of migraine, with a low potential for undesirable peripheral effects. [source] Peripheral Atherectomy: A Critical ReviewJOURNAL OF INTERVENTIONAL CARDIOLOGY, Issue 6 2007TROY A. BUNTING M.D. Atherectomy is experiencing increased interest from endovascular specialists as a therapeutic treatment in the peripheral arteries. Long studied in the coronary vasculature, atherectomy has several theoretical advantages that make it uniquely suited for the peripheral circulation. In particular, infra-inguinal peripheral arterial disease experiences physiologic stresses and forces that have made traditional percutaneous coronary treatments such as angioplasty and stenting not as successful. Restenosis has been a major problem for angioplasty and stenting alone. The SilverHawk atherectomy device has favorable short-term data but important longer-term data are limited and need further study. Laser atherectomy also has favorable applications in niche patients but the number of studies is limited. Unfortunately, athero-ablative technologies for peripheral arterial disease require more definitive objective data regarding 12-month and longer-term outcomes in order to obtain widespread scientific acceptance. [source] The Role of Myocardial KATP -Channel Blockade in the Protective Effects of Glibenclamide against Ischaemia in the Rat HeartBASIC AND CLINICAL PHARMACOLOGY & TOXICOLOGY, Issue 2 2002Roger J. Legtenberg This study addresses the possible involvement of KATP channels in this beneficial action of glibenclamide. We hypothesized that if glibenclamide improved postischaemic cardiac function by blocking of KATP channels, opening of these KATP channels should result in the opposite, namely detrimental effects on postischaemic heart function. Postischaemic functional loss and coronary blood flow were recorded during treatment with glibenclamide (4 ,mol.l,1; n=5), the KATP channel openers pinacidil (1 ,mol.l,1; n=5) and diazoxide (30 ,mol.l,1; n=5), the combination of glibenclamide with pinacidil (n=5) and glibenclamide with diazoxide (n=5), and vehicle (n=8). Both pinacidil and diazoxide significantly increased coronary blood flow 2,3 times, which was abolished by glibenclamide pre- and postischaemically. This confirms that under both flow conditions glibenclamide significantly blocks KATP channels in the coronary vasculature. The 12 min. global ischaemic incident resulted in a cardiac functional loss of 22.2±2.9% during vehicle. Glibenclamide reduced the cardiac functional loss to 4.3±1.2% (P<0.01). Interestingly, both pinacidil and diazoxide reduced the cardiac functional loss to 4.0±1.5% (P<0.01) and 2.9±1.4% (P<0.001), respectively. The combination pinacidil+glibenclamide resulted in additional protection compared with the individual components (0.6±0.1 versus 4.0±1.5%, P<0.05). Thus, in contrast to its effect on coronary vascular tone, the glibenclamide-induced improvement of postischaemic cardiac function may not be mediated through blockade of the KATP channel. Alternative mechanisms may be operative, such as uncoupling of the mitochondrial respiratory chain, thereby preconditioning the hearts against stunning. [source] The clinical anatomy of the coronary collateral circulationCLINICAL ANATOMY, Issue 1 2009Marios Loukas Abstract Although the structure and function of the coronary vasculature has been exhaustively studied, it still holds significant elements of mystery for the researcher and clinician. This is particularly true regarding the structure and function of the human collateral coronary circulation. Controversy still exists concerning the pathways of collateral vessels as well as their function. Controversies also exist relative to the methods used to delineate the pathways, these being additionally compounded by the lack of standardization of the studies and measurements. In this review, we summarize our current knowledge of this functionally significant vascular network. Clin. Anat. 22:146,160, 2009. © 2008 Wiley-Liss, Inc. [source] Development of the coronary vasculature and its implications for coronary abnormalities in general and specifically in pulmonary atresia without ventricular septal defectACTA PAEDIATRICA, Issue 2004AC Gittenberger-de Groot Aim: Coronary vascular anomalies are an important factor in congenital heart disease in the neonate. However, our knowledge of the pathomorphogenesis is still defective. Material and methods: 1) Study of coronary anomaly variations in congenital heart disease using specimens and 2) study of the role of epicardium-derived cells (EPDC) and neural crest cells in coronary vascular formation using quail-chicken chimeras. Results: The clinical and pathological data revealed the existence of ventriculo-coronary arterial communications during fetal life before pulmonary atresia was established. This supported a primary coronary developmental anomaly as the origin of some cases of pulmonary atresia as opposed to other cases in which the pulmonary orifice atresia was the primary anomaly. Our experimental work showed the high relevance of the development of the epicardium and epicardium-derived cells for the formation of the coronary vasculature, and showed the coronary vascular ingrowth into the myocardium and subsequently into the aorta and the right atrium. The absence of epicardium-derived cells leads to embryonic death, while delayed outgrowth could result in the absence of the main coronary arteries to pinpoint orifice formation. In these cases, the circulation was maintained through ventriculocoronary arterial communications. Neural crest cells were important for the patterning of the coronary vasculature. We have extended this knowledge to a number of other heart malformations. Conclusions: Coronary vascular anomalies are highly linked to the development of extracardiac contributors like the epicardium and the neural crest. A proper interaction between these cell types and the myocardium and aortic arterial wall are important for normal vascular development. [source] | |||||||||||||