Search Results
Results 251 - 300 of 1558
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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 ...
Ritt Martin - - 2008
OBJECTIVE: Increased wall-to-lumen ratio of small arteries is a predictor of adverse cardiovascular prognosis. We aimed to analyze retinal arteriolar structure in never-treated patients with essential hypertension and to test whether elevated blood pressure is associated with an increased wall-to-lumen ratio of retinal arterioles. METHODS: The study cohort comprised 21 ...
Chan Siu-Lung - - 2008
Moderate consumption of red wine is associated with a lower incidence of cardiovascular disease. Red wine polyphenols (RWP) have been proposed to be beneficial, but there is lack of evidence concerning the cerebrovascular effects of RWP. We studied the effect of local administration of a RWP extract (10(-2) mg/mL) on ...
Rezakhaniha Rana - - 2008
The three-dimensional biomechanical behavior of the vascular wall is best described by means of strain energy functions. Significant effort has been devoted lately in the development of structure-based models of the vascular wall, which account for the individual contribution of each major structural component (elastin, collagen, and vascular smooth muscle). ...
Newcomb William L - - 2009
BACKGROUND: Bipolar electrosurgical devices and ultrasonic devices are routinely used in open and advanced laparoscopic surgery for hemostasis. New electrosurgical and ultrasonic instruments demonstrate improved quality and efficiency in blood vessel sealing. METHODS: The 5-mm laparoscopic Gyrus PKS Cutting Forceps (PK), Gyrus Plasma Trissector (GP), Harmonic Scalpel (HS), EnSeal Tissue ...
Bieger Detlef - - 2008
OBJECTIVE: An increase in transmural pressure reportedly depolarizes myocytes in various arterial blood vessels. We have examined the relationship between transmural pressure and membrane potential (E(m)) in human saphenous veins with a view to determine whether contractile force generation, hence spasmogenesis in vein grafts, involves a similar process of mechanoelectrical ...
Mulvany Michael J - - 2008
Essential hypertension is treated primarily with a view to reducing blood pressure, and not with regard to normalizing the main pathological changes: the peripheral resistance and the cardiovascular structure. The aim of this review is to discuss whether normalization of the latter parameters, in particular resistance vessel structure, may also ...
Kajiya Fumihiko - - 2008
The phase opposition of velocity waveforms between coronary arteries (predominantly diastolic) and veins (systolic) is the most prominent characteristic of coronary hemodynamics. This unique arterial and venous flow patterns indicate the importance of intramyocardial capacitance vessels and variable resistance vessels during a cardiac cycle. It was shown that during diastole ...
Narayanan Nithya - - 2008
Changes in both pial arteriolar resistance (PAR) and simulated arterial-arteriolar bed resistance (SimR) of a physiologically based biomechanical model of cerebrovascular pressure transmission, the dynamic relationship between arterial blood pressure and intracranial pressure, are used to test the hypothesis that hypercapnia disrupts autoregulatory reactivity. To evaluate pressure reactivity, vasopressin-induced acute ...
Lee Sang Jin - - 2008
Numerous scaffolds that possess ideal characteristics for vascular grafts have been fabricated for clinical use. However, many of these scaffolds may not show consistent properties when they are exposed to physiologic vascular environments that include high pressure and flow, and they may eventually fail due to unexpected rapid degradation and ...
Carvalho Helena - - 2008
OBJECTIVES: The aim of this study was to determine longitudinal and radial gradients in oxygen tension (PO(2)) in microvessels of the hamster cheek pouch. METHODS: We measured PO(2) using the phosphorescence-quenching method in two orders of arterioles (45.8 +/- 5.5 and 19.9 +/- 1.8 micro m diameter), capillaries, and two ...
Timm Gerald W - - 2008
OBJECTIVE: To characterize the biomechanics of erectile function, as contrary reports have modelled the penis as an isotropic material and state that only axial buckling tests can effectively predict penile rigidity; that assumption is questioned and an alternative structure proposed and validated. METHODS: Three experimental physical cylindrical models of diameters ...
Comerford L - - 2008
Mammalian small arteries exhibit pressure-dependent myogenic behaviour characterised by an active constriction in response to an increased transmural pressure or an active dilatation in response to a decreased transmural pressure. This study aimed to determine whether pressure-dependent myogenic responses are a functional feature of amphibian arteries. Mesenteric and skeletal muscle ...
Kovar Petr - - 2008
The Czech Metrology Institute performs calibration and verification of noble gases stack monitors in nuclear power plants and nuclear research facilities. Together with Kr-85 and Xe-133, the radionuclide Ar-41 is measured using HPGe detectors and its activity is determined using a gamma-ray peak at 1293keV. The counting efficiency used in ...
Savvatimskiy A I - - 2008
As was shown in Gathers et al (1974 Report UCRL-51644 (Lawrence Livermore Laboratory, September 14)), graphite specimens of low initial densities (heated at gas pressure 2-4 kbar) contract to higher density still in the solid state and then continue further expanding up to the melting line. This effect was included in ...
Feihl François - - 2008
In the present review, microvascular remodelling refers to alterations in the structure of resistance vessels contributing to elevated systemic vascular resistance in hypertension. We start with some historical aspects, underscoring the importance of Folkow's contribution made half a century ago. We then move to some basic concepts on the biomechanics ...
Drummond Heather A - - 2008
Myogenic constriction is a vasoconstriction of blood vessels to increases in perfusion pressure. In renal preglomerular vasculature, it is an established mechanism of renal blood flow autoregulation. Recently, myogenic constriction has been identified as an important protective mechanism, preventing the transmission of systemic pressure to the fragile glomerular vasculature. Although ...
Warriner Renée K - - 2008
The existing computational model studies of pulsatile blood flow in arteries have assumed either rigid wall characteristics or elastic arterial wall behavior with wall movement limited to the radial direction. Recent in vivo studies have identified significant viscoelastic wall properties and longitudinal wall displacements over the cardiac cycle. Determining the ...
Taviani Valentina - - 2008
The mechanical properties of arterial walls have long been recognized to play an essential role in the development and progression of cardiovascular disease (CVD). Early detection of variations in the elastic modulus of arteries would help in monitoring patients at high cardiovascular risk stratifying them according to risk. An in ...
Blum M - - 2008
AIMS: The retina is protected against high blood pressure by the myogenic constriction of arterioles (the Bayliss effect). Hyperglycemia impairs this retinal autoregulation by endothelial dysfunction. The purpose of this prospective pilot study was to test whether improved metabolic control results in a measurable effect on the myogenic response of ...
Ishiguro M - - 2008
Constriction of small (100-200 microm) diameter cerebral arteries in response to increased intravascular pressure plays an important role in the regulation of cerebral blood flow. In arteries from healthy animals, these pressure-induced constrictions arise from depolarization of arterial smooth muscle leading to enhanced activity of L-type voltage-dependent calcium channels. Recently, ...
Jakobsson Lars - - 2008
Angiogenesis is crucial in the progression of a number of pathological conditions, such as diabetic retinopathy, rheumatoid arthritis, psoriasis, and cancer. In contrast to vessels in healthy tissues, the vasculature in these pathologies is highly unstable, constantly dissolving and renewing. Characteristically, vessels in pathologies have discontinuous basement membrane (BM) coverage. ...
Person Benjamin - - 2008
AIM: To compare the safety and efficacy of four energy-based vascular sealing and cutting instruments. METHODS: Blood vessels of various types and diameters were harvested from four pigs using four instruments: Harmonic ACE (Ethicon Endo-Surgery, Cincinnati, OH), LigaSure V and LigaSure Atlas (Valleylab, Inc., Boulder, CO; a division of Tyco ...
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