Search Results
Results 251 - 300 of 1713
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Warnock James N - - 2010
BACKGROUND AND AIM OF THE STUDY: Although the vasoactive agents, angiotensin II (Ang II) and 5-hydroxytryptamine (5-HT) are implicated in aortic heart valve disease, it is unclear how these compounds alter the biomechanical properties of valve leaflet tissue. The study aim was to characterize temporal changes in the elastic modulus ...
Hussain M - - 2010
The Carotid Artery Insufficiency Retinopathy (CAIR) is an uncommon sign of carotid artery obstruction. It is mainly found in patients with complete occlusion or severe obstruction of internal Carotid Artery (ICA). Retinopathy is caused by progressive and chronic hypoxia to ocular tissues. The purpose of the study is to describe ...
Hinson Holly E - - 2010
The use of antithrombotic therapy (anticoagulants and/or antiplatelets) in the setting of traumatic cervical arterial dissection (CAD) for the prevention of stroke remains controversial. This issue is further complicated by the frequent co-existence of intracranial hemorrhage (ICH) and other intracranial injuries, and also the wide variability in treatment due to ...
Javey Golnaz - - 2010
The authors report the management of a ruptured retinal arterial macroaneurysm and associated hemorrhages with intravitreal injections of bevacizumab. A 79-year-old woman presented with a history of systemic arterial hypertension and a ruptured retinal arterial macroaneurysm with pre-retinal, intraretinal, and subretinal hemorrhages extending into the macula. Visual acuity at presentation ...
Biswas Rohan - - 2010
Ultrasonography for the noninvasive assessment of tissue properties has enjoyed widespread success. With the growing emphasis in recent years on arteriovenous fistulae (AVFs) for dialysis vascular access in patients with end-stage renal disease, and on reducing AVF failures, there is increasing interest in ultrasound for the preoperative evaluation of the ...
Misra Sanjay - - 2010
To evaluate the wall shear stress, protein expression of matrix metalloproteinase (MMP)-2 and MMP-9 and tissue inhibitor of matrix metalloproteinase (TIMP)-1 and TIMP-2, and vessel area over time in a porcine model for polytetrafluoroethylene (PTFE) hemodialysis grafts. In 21 pigs, subtotal renal infarction was created, and 28 days later, a ...
Teeter M G MG Department of Clinical Studies, University of Guelph, Ontario, - - 2010
Arterial calcification is found frequently in the pulmonary artery of racehorses, but the aetiology is unknown. Calcification might be associated with increased wall stress due to arterial geometry (shape) and exercise-induced hypertension. High wall stress levels are found in the regions associated with calcified lesion formation, exacerbated as transluminal pressure ...
Brum J J Instituto de Fisica, Facultad de Ciencias, Universidad de la Republica, Igua 4225, Montevideo, Uruguay. - - 2010
The early detection of biomechanical modifications in the arterial wall could be used as a predictor factor for various diseases, for example hypertension or atherosclerosis. In this work a transient elastography technique is used for the in vitro evaluation of the arterial wall elasticity. The obtained Young modulus is compared ...
Zajarevich N N CITEFA, Ministry of Defense, Villa Martelli, Buenos Aires, - - 2010
In this present paper, we showed that wavelet analysis (WA) has the potential for extracting specific features from measured arterial diameter and pressure waveforms. The fifth detail of the Daubechies 4 (Db4) wavelet appears to be the most appropriate level for application, in order to analyze artery waveforms and was ...
Li Ye Y Brunel Institute for Bioengineering, Brunel University, Greater London, UK. - - 2010
Wave speed is one of the key factors describing wave propagation in arteries [1]. Local wave speed is directly related to the arterial wall properties [2]. With aging, arterial wave speed increases due to the stiffening of arterial wall, and also related to arterial disease.
Bernal Miguel M Mayo Clinic College of Medicine, Rochester, MN 55905, USA. - - 2010
Arterial elasticity has gained importance in the past few decades as a predictor of cardiovascular diseases and mortality. Measuring the speed of propagation of the pressure wave traveling in the wall of the arteries has been used for a very long time to estimate the mechanical properties of the artery. ...
Pessana F F Electronic Department, Buenos Aires Regional Faculty, National Technological University, Medrano 951, (C1179AAQ), Ciudad Autónoma de Buenos Aires, Argentina. - - 2010
Wall artery viscoelastic properties (WAVP) are correlated with structural and functional state of the arterial system. An accurate estimation of these properties is achieved measuring wall instantaneous diameter and pressure signals. The aim of this work was to evaluate a new non invasive estimation method of the instantaneous arterial diameter ...
Balay G G Instituto de Fisica, Facultad de Ciencias, UdelaR, Montevideo, Uruguay. - - 2010
In several clinical and experimental circumstances, it is widely necessary to characterize the bio-mechanical changes induced by atherosclerosis to the arterial wall. In this context, the purpose of this paper is twofold. Firstly, to propose a low cost ultrasound setup to improve artery radii determination in elasticity experiments, based on ...
Xu Da D Department of Electrical and Computer Engineering, Michigan State University, East Lansing, MI 48824, USA. - - 2010
Pulse wave velocity (PWV) determined through the foot-to-foot time delay between carotid and femoral artery waveforms is an index of aortic stiffness with proven clinical value. However, handheld transducers, which are often used to non-invasively measure the waveforms, are prone to motion artifact that may limit the full potential of ...
Karmy-Jones Riyad R Riyad Karmy-Jones, Desarom Teso, Nichole Jackson, Division of Cardiac, Thoracic and Vascular Surgery, Southwest Washington Medical Center, Suite 330 400 NE Mother Joseph Place, Vancouver, WA 98664, United - - 2009
Traumatic thoracic aortic injury remains a major cause of death following motor vehicle accidents. Endovascular approaches have begun to supersede open repair, offering the hope of reduced morbidity and mortality. The available endovascular technology is associated with specific anatomic considerations and complications. This paper will review the current status of ...
Lindeman Jan H N - - 2010
An aneurysm of the aorta is a common pathology characterized by segmental weakening of the artery. Although it is generally accepted that the vessel-wall weakening is caused by an impaired collagen metabolism, a clear association has been demonstrated only for rare syndromes such as the vascular type Ehlers-Danlos syndrome. Here ...
Huang Jianbin - - 2010
Loss of fibulin-4 during embryogenesis results in perinatal lethality because of aneurysm rupture, and defective elastic fiber assembly has been proposed as an underlying cause for the aneurysm phenotype. However, aneurysms are never seen in mice deficient for elastin, or for fibulin-5, which absence also leads to compromised elastic fibers. ...
Coutard Michèle - - 2010
BACKGROUND/AIM: The intraluminal thrombus (ILT) is considered to participate in abdominal aortic aneurysm (AAA) evolution. To assess whether this role proceeds via ILT influence on biological activity of the AAA wall, we studied the relationships between the levels of some relevant proteases and microparticles (MP) released by ILT versus wall ...
Georgakarakos E - - 2010
Using finite element analysis, we evaluated if the site of an aortic bleb, known to be prone to rupture, coincides with the location of peak wall stress (PWS) in a patient-specific abdominal aortic aneurysm (AAA) model. PWS was not located at the bleb site, even when stress values were estimated ...
Chung Sangwon - - 2010
Current surgical therapy for diseased vessels less than 6mm in diameter involves bypass grafting with autologous arteries or veins. Although this surgical practice is common, it has significant limitations and complications, such as occlusion, intimal hyperplasia and compliance mismatch. As a result, cardiovascular biomaterials research has been motivated to develop ...
Crapo Peter M - - 2010
Compliance mismatch is a significant challenge to long-term patency in small-diameter bypass grafts because it causes intimal hyperplasia and ultimately graft occlusion. Current engineered grafts are typically stiff with high burst pressure but low compliance and low elastin expression. We postulated that engineering small arteries on elastomeric scaffolds under dynamic ...
Yang Feng-Yi - - 2009
Continuous high-intensity focused ultrasound (HIFU) at various intensities has been shown to induce functional changes in arteries. The objective of the current study was to investigate the functional changes in arteries when pulsed HIFU is used at various acoustic power levels. Sonication was applied at an ultrasound frequency of 1 ...
Han Hai-Chao - - 2009
The stability of blood vessels under the lumen blood pressure is essential to the maintenance of normal arterial function. Buckling equations have been established recently for linear and nonlinear elastic artery models with assumed sinusoidal mode shapes. However, the theoretical base for the assumption is not clear. This study established ...
Souza Joyce G R - - 2009
Angiostrongylus lenzii n. sp. (Nematoda: Metastrongyloidea) is described and illustrated from the pulmonary artery of the wild rodent Akodon montensis Thomas, 1913, collected in the municipality of Teresopólis, Rio de Janeiro State, Brazil. It represents the 17th species of the genus and the 2nd in South America as parasites in ...
Hogan Benjamin M - - 2009
The development of arteries, veins and lymphatics from pre-existing vessels are intimately linked processes controlled by a number of well-studied reiteratively acting signalling pathways. To delineate the mechanisms governing vessel formation in vivo, we performed a forward genetic screen in zebrafish and isolated the mutant expando. Molecular characterisation revealed a ...
Nakamura Ryuji - - 2009
Arterial mechanical impedance is a characteristic of arterial dynamics that is determined by photoplethysmographic amplitude and direct arterial pressure, while mechanical impedance is indicated by stiffness, viscosity, and inertia. We compared the parameters of mechanical impedance and photoplethysmographic amplitude to estimate the magnitude of stress response in patients undergoing general ...
Hernandez-Garcia Luis - - 2009
Cerebral blood flow-dependent phase differences between tagged and control arterial spin labeling images are reported. A biophysical model is presented to explain the vascular origin of this difference. Arterial spin labeling data indicated that the phase difference is largest when the arterial component of the signals is preserved but is ...
Cardamone L - - 2009
The structural protein elastin endows large arteries with unique biological functionality and mechanical integrity, hence its disorganization, fragmentation, or degradation can have important consequences on the progression and treatment of vascular diseases. There is, therefore, a need in arterial mechanics to move from materially uniform, phenomenological, constitutive relations for the ...
Cousin Maud - - 2010
Angiotensin II is a potent growth factor involved in arterial wall homeostasis. In resistance arteries, chronic increases in blood flow induce a rise in diameter associated with arterial wall hypertrophy. Nevertheless, the role of angiotensin II in this remodeling is unknown. We investigated the effect of blocking angiotensin II production ...
van der Giessen Alina G - - 2010
Wall shear stress, the force per area acting on the lumen wall due to the blood flow, is an important biomechanical parameter in the localization and progression of atherosclerosis. To calculate shear stress and relate it to atherosclerosis, a 3D description of the lumen and vessel wall is required. We ...
Krous Henry F HF Department of Pathology, Rady Children's Hospital-San Diego, CA 92123, USA. - - 2009
Previous studies addressing pulmonary artery morphology have compared cases of sudden infant death syndrome (SIDS) to controls but none have compared demographic profiles, exposure to potentially hypoxic risk factors and other pathologic variables in SIDS cases grouped according to pulmonary artery medial smooth muscle thickness. To compare the relative medial ...
Schmid H - - 2010
Recent experimental and computational studies have shown that transmurally heterogeneous material properties through the arterial wall are critical to understanding the heterogeneous expressions of constituent degrading molecules. Given that expression of such molecules is thought to be intimately linked to local magnitudes of stress, modelling the transmural stress distribution is ...
Scuteri Angelo - - 2010
We evaluated whether specific clusters of metabolic syndrome (MetS) components differentially impact on arterial structure and function, and whether the impact is similar in men and in women. Components of the MetS and arterial properties were assessed in 6148 subjects, aged 14-102 in a cluster of four towns in Sardinia, ...
Oda Shinichiro - - 2010
OBJECTIVES: Reliable suture line hemostasis should improve the outcome of aortic surgery. We examined the hemostatic effect and the tissue response of a novel elastomeric surgical sealant. METHODS: Using porcine internal carotid arteries, we performed 16 end-to-end anastomoses with four stitches of simple interrupted sutures under full heparinization. The anastomoses ...
Troidl Kerstin - - 2009
Previous studies showed that targeted eNOS disruption in mice with femoral artery occlusion does not impede - and transgenic eNOS over-expression does not stimulate - collateral artery growth following femoral artery occlusion, suggesting that NO from eNOS does not play a role in arteriogenesis. However, pharmacological NOS inhibition with L-NAME ...
Kanbay Mehmet - - 2010
Patients with end-stage renal disease treated by chronic dialysis have an impressive mortality, which more than half of this mortality is attributable to cardiovascular disease. Despite stratification for sex, race, and the presence of diabetes, cardiovascular disease mortality is 10-30 times higher in dialysis patients compared to general population. In ...
Xu X Y - - 2010
BACKGROUND: Functional imaging using positron emission tomography (PET) showed increased metabolic activities in the aneurysm wall prior to rupture, whereas separate studies using finite element analysis techniques found the presence of high wall stresses in aneurysms that subsequently ruptured. This case series aimed to evaluate the association between wall stress ...
Vriens Dennis - - 2009
For the quantification of dynamic (18)F-FDG PET studies, the arterial plasma time-activity concentration curve (APTAC) needs to be available. This can be obtained using serial sampling of arterial blood or an image-derived input function (IDIF). Arterial sampling is invasive and often not feasible in practice; IDIFs are biased because of ...
Witter Kirsti - - 2010
Tissue glues are used during surgical treatment of acute aorta dissection although some glues release toxic products and thus alter the histological structure of the vessel wall. The aim of our study was to use a porcine experimental model of infrarenal aorta dissection to compare histological changes of the vessel ...
van den Akker Jeroen - - 2010
Blood flow regulation by small arteries and arterioles includes adaptation of both vascular tone and structure. It is becoming clear that tone and remodeling of resistance vessels are highly interrelated. Indeed, concepts pointing to continuous resistance artery adaptation and plasticity are emerging. The purpose of this review is to summarize ...
Klein Andrew J - - 2009
BACKGROUND: The unique physical forces exerted on the femoropopliteal (FP) artery during movement have been implicated in the high rates of restenosis and stent fracture in this artery. Conformational changes in the FP artery during movement are important surrogates of these forces. This study sought to quantify the conformational change ...
Park Ji Kang - - 2009
In this study, we evaluated the wall of saccular cerebral aneurysms (SCAs) using two-dimensional double inversion recovery black-blood sequence (BBDI). We examined 14 patients with an unruptured SCA (USCA). The BBDI was peripheral-pulse gated, and was acquired during the mid-diastolic period. We evaluated whether the aneurysmal wall could be visualized ...
Cohn Jay N - - 2009
Noninvasive evaluation of the health of the vasculature is an increasingly important approach to identifying individuals at risk for cardiovascular morbid events. Vascular health assessment involves functional and structural examination of the large and small arteries. Endothelial dysfunction, which alters small artery function, is a key contributor to progressive structural ...
Matthews Peter B - - 2009
BACKGROUND AND AIM OF THE STUDY: Pulmonary autograft dilation can lead to aortic insufficiency requiring reoperation. Remodeling occurs when the pulmonary root is subjected to systemic pressure. It is unknown whether a regional variability of the material properties exists within the root, resulting in unequally distributed wall stress prior to ...
Yazici Ilker - - 2009
In this article, we present the use of triangulation for end-to-side microvascular arterial anastomosis. The classic end-to-side anastomosis starts by putting 2 sutures 180 degrees apart to the lateral arteriotomy aperture that is parallel to the longitudinal axis. We are performing triangulation in end-to-side microvascular artery anastomoses by putting 3 ...
Wang Chong - - 2009
The stress distribution in the vessel wall has an important bearing on vascular function in health and disease. We studied the relationship between the transmural stress distribution and the opening angle (OA) to determine the stress gradient. The simulation of wall stress was based on transmural measurements of strain and ...
Chen Henry Y - - 2010
Vascular cross-clamping is applied in many cardiovascular surgeries such as coronary bypass, aorta repair and valve procedures. Experimental studies have found that clamping of various degrees caused damage to arteries. This study examines the effects of popular clamps on vessel wall. Models of the aorta and clamp were created in ...
Massey Philip G PG University of Washington, Seattle, WA 98195-7710, - - 2009
Urokinase-type plasminogen activator (uPA) is expressed at increased levels in stenotic, atherosclerotic human arteries. However, the biological roles of uPA in the artery wall are poorly understood. Previous studies associate uPA with both acute vasoconstriction and chronic vascular remodeling and attribute uPA-mediated vasoconstriction to the kringle - not the catalytic ...
Kawasaki Toshihiro - - 2009
OBJECTIVE: The elastic properties of the carotid arterial wall have not been directly characterized in the clinical setting. Strain rate (SR) imaging is a newly developed echocardiographic method developed for imaging the tissue motion of the myocardium. The purpose of this study was to directly estimate the elastic properties of ...
Bjarnegård Niclas - - 2010
The normal aging process of the brachial artery (BA) wall is of specific interest since it is often selected as a model artery in studies of vascular function. With echo-tracking ultrasound, diameter, absolute diameter change, and intima-media thickness (IMT) were registered in 60 healthy subjects, 21-86 yr (30 men), at ...
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