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Safar M E - - 2010
Physiologically, macro- and microcirculation differ markedly as macrocirculation deals with pulsatile pressure and flow and microcirculation with steady pressure and flow. Various such haemodynamic aspects correspond to a large heterogeneity in the structure and function of the vascular tree. In the past, diseases such as hypertension and diabetes mellitus were ...
Kawasaki Ryo - - 2009
To describe the prospective relationship of retinal vessel diameters with risk of hypertension in a multiethnic population-based cohort. The Multi-Ethnic Study of Atherosclerosis is a population-based study of subclinical cardiovascular disease among white, African-American, Hispanic, and Chinese American adults aged 45-84 years. Retinal vessel diameters were measured using a standardized ...
Sharif-Naeini Reza - - 2009
Autosomal-dominant polycystic kidney disease, the most frequent monogenic cause of kidney failure, is induced by mutations in the PKD1 or PKD2 genes, encoding polycystins TRPP1 and TRPP2, respectively. Polycystins are proposed to form a flow-sensitive ion channel complex in the primary cilium of both epithelial and endothelial cells. However, how ...
Lawrence Amanda R - - 2009
Arterial axial strains, present in the in vivo environment, often become reduced due to either bypass grafting or the normal aging process. Since the prevalence of hypertension increases with aging, arteries are often exposed to both decreased axial stretch and increased transmural pressure. The combined effects of these mechanical stimuli ...
Sidorov V A - - 2009
We synthesized tetragonal α-FeSe by melting a powder mixture of iron and selenium at high pressure. Subsequent annealing at normal pressure results in removing traces of hexagonal β-FeSe, formation of a rather sharp transition to a superconducting state at T(c)∼7 K, and the appearance of a magnetic transition near T(M) = ...
Zhang Ye - - 2009
BACKGROUND: To realize atraumatic vessel occlusion, a new hemostatic clamp using superelastic shape memory alloy (SMA) as a pressure control limiter has been proposed. It was designed taking advantage of a unique mechanical property of SMA. The ability to control pressure with the newly designed SMA clamp was investigated. The ...
Guan Zhengrong Z Department of Physiology, Medical College of Georgia, Augusta, GA 30912, - - 2009
The mechanotransduction mechanism underlying the myogenic response is poorly understood, but evidence implicates participation of epithelial sodium channel (ENaC)-like proteins. Therefore, the role of ENaC on the afferent arteriolar myogenic response was investigated in vitro using the blood-perfused juxtamedullary nephron technique. Papillectomy was used to isolate myogenic influences by eliminating ...
Jeganathan V Swetha E - - 2009
Blood pressure has a significant effect on retinal arterioles. There are few data on whether this effect varies by race/ethnicity. We examined the relationship of blood pressure and retinal vascular caliber in a multi-ethnic Asian population. The study is population-based and cross sectional in design. A total of 3749 Chinese, ...
Xiao DaLiao D Center for Perinatal Biology, Department of Physiology and Pharmacology, Loma Linda University School of Medicine, Loma Linda, CA 92350, - - 2009
Cocaine abuse is a significant problem among pregnant women. The present study tested the hypothesis that prenatal cocaine exposure impairs myogenic reactivity of coronary arteries in adult offspring. Pregnant rats received cocaine (30 mg kg(-1) day(-1)) or saline from days 15 to 21 of gestational age, and experiments were conducted ...
Wagenseil Jessica E JE Department of Biomedical Engineering, Saint Louis University, Washington University School of Medicine, St. Louis, Missouri 63110, - - 2009
An important factor in the transition from an open to a closed circulatory system was a change in vessel wall structure and composition that enabled the large arteries to store and release energy during the cardiac cycle. The component of the arterial wall in vertebrates that accounts for these properties ...
Xie Hui H Department of Neonatology, Children's Research Institute, Children's National Medical Center, The George Washington University, Washington, DC, - - 2010
Hypoxia/reoxygenation (H/R) associated with extracorporeal membrane oxygenation disrupts cerebral autoregulation. However, the underlying mechanisms remain poorly understood. The present study was designed to investigate the role of sensory C-fibers in myogenic responsiveness of cerebral arteries. Arterial diameter and intraluminal pressure were simultaneously measured in vitro on rat posterior cerebral arteries. ...
VanLandingham Lauren G - - 2009
Recent studies suggest certain epithelial Na(+) channel (ENaC) proteins may be components of mechanosensitive ion channel complexes in vascular smooth muscle cells that contribute to pressure-induced constriction in middle cerebral arteries (MCA). However, the role of a specific ENaC protein, betaENaC, in pressure-induced constriction of MCAs has not been determined. ...
Hill Michael A MA Dalton Cardiovascular Research Center and Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, MO 65211, USA. - - 2009
The arteriolar myogenic response, which is defined as vasoconstriction to increases in intraluminal pressure and, conversely, dilation to a reduction in pressure, is key in the setting of vascular resistance, local control of microvascular blood flow through autoregulation, and in the control of capillary hydrostatic pressure. Although considerable progress has ...
Zamir Mair - - 2009
The dynamics of blood supply to a vascular bed depend on lumped mechanical properties of that bed, namely the compliance (C), resistance (R), viscoelasticity (K), and inertance (L). While the study of regulatory mechanisms has so far placed the emphasis largely on R, it is not known how the remaining ...
Agabiti-Rosei Enrico - - 2009
Although it is recognized that the cause of hypertension can be various, once blood pressure has become established structural changes emerge in the systemic vasculature. In medium- and large-sized vessels, as in the left ventricle, there is clear histological evidence of hypertrophy of the medial smooth muscle layers but, downstream ...
Truslow James G JG Department of Biomedical Engineering, Boston University, 44 Cummington Street, Boston, MA 02215, - - 2009
This computational study analyzes how to design a drainage system for porous scaffolds so that the scaffolds can be vascularized and perfused without collapse of the vessel lumens. We postulate that vascular transmural pressure--the difference between lumenal and interstitial pressures--must exceed a threshold value to avoid collapse. Model geometries consisted ...
Pemp Berthold - - 2009
OBJECTIVE Flicker-induced vasodilatation is reduced in patients with vascular-related diseases, which has at least partially been attributed to endothelial dysfunction of retinal vessels. Currently, the standard method to assess endothelial function in vivo is flow-mediated vasodilatation (FMD). Thus, the present study was performed to investigate whether a correlation exists between ...
Lawrence Amanda R - - 2009
Physiological axial strains range between 40 and 60% in arteries, resulting in stresses comparable to those due to normal blood pressure or flow. To investigate the contribution of axial strain to arterial remodeling and function, porcine carotid arteries were cultured for 9 days at physiological and reduced axial stretch ratios ...
Withers S B - - 2009
Pregnancy-induced changes in uterine artery function play a critical role in ensuring adequate placental perfusion. Responses of these vessels to pressure (myogenic responsiveness) may contribute to this. The overall myogenic properties of uterine arteries may depend upon the integration of a number of different factors, including effects of pre-constrictor stimuli, ...
Rachev Alexander - - 2009
This study proposes a mathematical model for studying stability of arteries subjected to a longitudinal extension and a periodic pressure. An artery was considered as a straight composite beam comprised of an external thick-walled tube and a fluid core. The dynamic criterion for stability was used, based on analyzing the ...
Tschan C A - - 2009
BACKGROUND: Waterjet dissection represents a useful technique for many surgical procedures. In this experimental study, the technical features and dissection qualities of the new Erbejet 2 with its new pump and nozzle applicator system are evaluated for its neurosurgical use compared to the established Helix Hydro-Jet. METHODS: One hundred twenty-six ...
Kölegård Roger - - 2009
Displacement of blood to the lower portion of the body that follows a postural transition from recumbent to erect is augmented by a prolonged period of recumbency (bedrest). Information is scarce as to what extent this augmented blood-volume shift to dependent veins is attributable to increased distensibility of the veins. ...
Neuschmelting Volker - - 2009
BACKGROUND: Vasopressor-induced hypertension is routinely indicated for prevention and treatment of cerebral vasospasm (CVS) after subarachnoid haemorrhage (SAH). Mechanisms underlying patients' clinical improvement during vasopressor-induced hypertension remain incompletely understood. The aim of this study was to evaluate angiographic effects of normovolaemic Norepinephrine (NE)-induced hypertension therapy on the rabbit basilar artery ...
Dhar S K - - 2009
We report magnetization, heat capacity and electrical resistivity measurements on CePtZn, which crystallizes in the orthorhombic TiNiSi type structure. Magnetization and electrical resistivity on the iso-structural series of compounds Ce(1-x)La(x)PtZn (x = 0.1, 0.2 0.5 and 1) were also carried out. The electrical resistivity of CePtZn was also measured in ...
Izzard Ashley S - - 2009
BACKGROUND: Although, it is accepted that there is an excess of cardiovascular mortality in acromegaly, it is uncertain whether this is due to the direct effects of growth hormone-induced-cardiomyopathy or is a consequence of atherosclerosis secondary to the metabolic syndrome often observed in this condition. Direct comparison of a mouse ...
Valentín A - - 2009
Arteries exhibit a remarkable ability to adapt to sustained alterations in biomechanical loading, probably via mechanisms that are similarly involved in many arterial pathologies and responses to treatment. Of particular note, diverse data suggest that cell and matrix turnover within vasoaltered states enables arteries to adapt to sustained changes in ...
Umeda Hisashi - - 2009
OBJECTIVES: Percutaneous coronary interventions for very small vessels are common in clinical practice despite an unavailability of the 2.25-mm sirolimus-eluting stent (SES) in some countries. We sought to evaluate the clinical and angiographic outcomes of 2.5-mm SES implantation at lower deployment pressures in very small coronary arteries. METHODS: Between June ...
Kölegård Roger - - 2009
AIM: The purpose was to study the effects of moderately to markedly increased local intravascular pressures on the flow characteristics in human limb veins. METHODS: The subject was either seated inside a pressure chamber with one arm slipped through a hole in the chamber door (n = 7) or positioned ...
Christman Mairgareth A - - 2009
* Eudicot angiosperms with greater vulnerability to xylem cavitation tend to have vessels with greater total area of inter-vessel pits, which inspired the 'rare pit' hypothesis: the more pits per vessel, by chance the leakier will be the vessel's single air-seeding pit and the lower the air-seeding threshold for cavitation ...
Luzar Bostjan - - 2009
Hemorrhagic blisters have rarely been described developing in the background of either genital or extragenital lichen sclerosus and have invariably been designated clinically as telangiectatic, hemorrhagic or bullous lichen sclerosus. We describe three patients with extragenital and genital lichen sclerosus, who presented clinically with hemorrhagic plaques and/or papules. In addition ...
Pantovic Suzana - - 2009
In this study we postulated that during acute renal failure induced by gentamicin the transient or dynamic response of blood vessels could be affected, and that antioxidants can prevent the changes in dynamic responses of blood vessels. The new approach to ex vivo blood vessel experiments in which not only ...
Chamberlain Janet - - 2009
BACKGROUND: Atherosclerosis is an inflammatory process that develops in individuals with known risk factors that include hypertension and hyperlipidaemia, influenced by diet. However, the interplay between diet, inflammatory mechanisms and vascular risk factors requires further research. We hypothesised that interleukin-1 (IL-1) signaling in the vessel wall would raise arterial blood ...
Christman Mairgareth A - - 2009
Eudicot angiosperms with greater vulnerability to xylem cavitation tend to have vessels with greater total area of inter-vessel pits, which inspired the 'rare pit' hypothesis: the more pits per vessel, by chance the leakier will be the vessel's single air-seeding pit and the lower the air-seeding threshold for cavitation to ...
Qian Jie-Sheng - - 2009
Arterial smooth muscle cell proliferation is a key event in the development of hypertension associated vascular disease. Although previous studies have found that pressure itself can promote cell proliferation and DNA synthesis in vascular smooth muscle cells, the mechanisms are not clear. Recent accumulating evidence indicate that volume-regulated chloride channel ...
Frank Jennifer - - 2009
Resistant hypertension, defined as failure to achieve target blood pressure despite the use of optimal or maximum doses of at least 3 agents, one of which is a diuretic, or requiring 4 or more medications to achieve blood pressure goal, is likely to affect up to 20% of all patients ...
Hardy Brian S - - 2009
Poly(dimethylsiloxane) (PDMS) microchannels are commonly used microfluidic structures that have a wide variety of biological testing applications, including the simulation of blood vessels to study the mechanics of vascular disease. In these studies in particular, the deformation of the channel due to the pressure inside is a critical parameter. We ...
Elbers Paul W G - - 2009
It has become possible to image the human microcirculation at the bedside using sidestream dark field (SDF) imaging. This may help the clinician when correlation between global and microvascular hemodynamics may not be straightforward. Ketanserin, a serotonin and alpha-1 adrenoceptor antagonist, is used in some countries to treat elevated blood ...
Mor Amir - - 2008
Hyperbaric environments over 1.1 MPa induce in mammals and humans the high pressure neurological syndrome (HPNS). HPNS is characterized by cognitive and motor decrements associated with sleep disorders, EEG changes, tremor, and convulsions. Previously, it was proposed that augmented responses of the glutamatergic N-methyl-D-aspartate receptor (NMDAR) may be involved. Recently, ...
Linfante Italo - - 2008
OBJECTIVE: Nicardipine has been used to treat cerebral vasospasm in patients with aneurysmal subarachnoid hemorrhage. Intra-arterial (IA) infusion of high concentrations of nicardipine decreases procedure time, but it may affect hemodynamic parameters. In addition, a quantitative measurement of improvement of vessel diameter on the angiograms has not been performed. METHODS: ...
Davis Michael J - - 2009
We tested the hypothesis that lymphatics would exhibit myogenic constrictions and dilations to intraluminal pressure changes. Collecting lymphatic vessels were isolated from rat mesentery, cannulated, and pressurized for in vitro study. The lymphatic diameter responses to controlled intraluminal pressure steps of different magnitudes were tested in the absence and presence ...
Sooriakumaran Prasanna - - 2009
OBJECTIVE: To assess risk factors and predictors of failure of the Hem-o-lok(TM) vascular clip (Weck Closure Systems, Research Triangle Park, NC, USA) using vessels harvested from a porcine model. MATERIALS AND METHODS: Vessels of various diameters were harvested from a porcine model, clipped at 90 degrees or 45 degrees using ...
Lott Mary E J ME Penn State Heart and Vascular Institute, Pennsylvania State University College of Medicine, Hershey, PA 17033, - - 2009
The purpose of this study was to examine upper and lower limb vasoconstrictor responses to changes in transmural pressure in humans. Brachial and femoral blood mean blood velocity (MBV) and vessel diameter (Doppler ultrasound) were measured in 20 supine healthy subjects (10 men and 10 women; 27 +/- 1 yr; ...
Birla Ravi K - - 2009
We have previously described a model to implant dissociated cells into a cylindrical, vascularized bed in vivo to promote the formation of functional cardiac muscle constructs. We now investigate the cellular organization and the ability of the constructs to generate intra-luminal pressure. Primary cardiac cells were isolated from hearts of ...
Giannattasio Cristina - - 2008
Use of local arterial distensibility measurements by change in carotid artery diameter divided by pulse pressure has limitations because blood pressure is often taken in a vessel distant or at a time different from where and when change in diameter is taken. In 92 subjects (23 to 91 years of ...
Hendlin Kari - - 2008
PURPOSE: The dynamics of percutaneous balloon expansion may differ with increasing extrinsic compressive forces and increasing inflation pressures. This study compares the ability of percutaneous balloons to expand under different radial constrictive forces. MATERIALS AND METHODS: Three 30F nephrostomy balloons were tested: Bard X-Force, Boston Scientific Microvasive Amplatz Tractmaster, and ...
Liew Gerald - - 2008
OBJECTIVE: Fractals represent a type of derived geometric pattern that permits the characterization of the branching pattern of retinal vessels. We examined a new semiautomated method to measure retinal vessel fractals. DESIGN: Methodology study. PARTICIPANTS: Three hundred randomly selected participants from the population-based Blue Mountains Eye Study. METHODS: We developed ...
Bruner Emiliano - - 2008
Although research today ranges from molecular to universe scale, many issues regarding gross anatomy remain totally neglected. Within the framework of the endocranial morphogenesis and evolution, understanding the role and variation of the middle meningeal artery relies upon the very limited, scattered, and descriptive information available. The meninges are supplied ...
Salzer Deborah A - - 2008
The purpose of this investigation was to assess the interactive influence of sympathetic activation and supplemental nitric oxide (NO) on brachial artery distensibility vs. its diameter. It was hypothesized that 1) sympathetic activation and NO competitively impact muscular conduit artery (brachial artery) mechanics, and 2) neurogenic constrictor input affects conduit ...
Eiken Ola - - 2008
We hypothesized that exposure to prolonged recumbency (bedrest), and thus reductions of intravascular pressure gradients, increases pressure distension in arteries/arterioles in the legs. Ten subjects underwent 5 wk of horizontal bedrest. Pressure distension was investigated in arteries and arterioles before and after the bedrest, with the subject seated or supine ...
Wallwiener Christian W - - 2008
Bipolar vessel sealing is pivotal in laparoscopic hemostasis. However, major coaptive desiccation parameters have yet to be investigated in detail. The current investigation aims to study the impact of compressive pressure, thermal conduction, and electrical current effects on seal quality in a randomized, controlled experimental trial in an in vitro ...
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