Search Results
Results 551 - 600 of 1823
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Arita R - - 2007
By means of a combination of the local density approximation and dynamical mean field theory (LDA + DMFT), we study the possibility of making a d(1) analogue of d(9) cuprates on the basis of Sr(2)VO(4). We calculate the electronic structure of Sr(2)VO(4) under pressure, and show that while the material ...
Matsumoto Naoki - - 2007
High-pressure structures of Ar(H(2))(2) are studied with possible molecular dissociation and metallization using density functional theory in the local density approximation (LDA) and generalized gradient approximation (GGA) for the exchange-correlation energy. We have estimated the transition pressure from the low-pressure MgZn(2)-type structure to the high-pressure AlB(2)-type structure to be around ...
Howitt Lauren - - 2007
Snoring-associated vibration energy transmission from the upper airway to the carotid artery has been hypothesized as a potential atherosclerotic plaque initiating/rupturing event that may provide a pathogenic mechanism linking snoring and embolic stroke. We examined transmission of oscillatory pressure waves from the pharyngeal lumen to the common carotid artery wall ...
Dahan Albert - - 2007
Human breathing is regulated by feedback and feed-forward control mechanisms, allowing a strict matching between metabolic needs and the uptake of oxygen in the lungs. The most important control mechanism, the metabolic ventilatory control system, is fine-tuned by two sets of chemoreceptors, the peripheral chemoreceptors in the carotid bodies (located ...
Muldoon Matthew F - - 2007
BACKGROUND AND PURPOSE: Central nervous system serotonergic neurotransmission appears to play a role in mood disorders, eating habits, and sleep, and also modulates blood pressure and metabolism. This investigation tested a hypothesized association between central serotonergic functioning and preclinical atherosclerosis. METHODS: Subjects were 244 adults 30 to 55 years of ...
Aleksic M - - 2007
BACKGROUND: Induced hypertension is widely recommended as a protective measure in carotid endarterectomy (CEA) to prevent shunt insertion. In this study changes of systemic blood pressure were evaluated in relation to the shunt rate when CEA was performed under local anaesthesia. MATERIALS AND METHODS: In 930 CEAs performed for a ...
Melenovsky Vojtech - - 2007
BACKGROUND: Peripheral wave reflection augments central blood pressure and contributes to cardiac load. This pressure augmentation is not quantifiable from brachial cuff pressure but can be determined from carotid pulsations using the augmentation index (AI). However, carotid tonometry is technically challenging and difficult to standardize in practice. We tested whether ...
Ristagno Giuseppe - - 2007
OBJECTIVES: Coincident with "agonal" gasping during cardiac arrest, there are prominent increases in stroke volumes even in the absence of chest compression. In the present study, we tested the hypothesis that gasps also increase carotid blood flow (CBF) during untreated cardiac arrest. MATERIALS AND METHODS: The tracheas of nine domestic ...
Gmitrov Juraj - - 2007
Increasing evidence suggests that time-varying and static magnetic fields in the environment might affect the cardiovascular system. To explore the underlying physiology, the effect of static magnetic fields (SMFs) on the carotid baroreflex control of microcirculation was studied. Twenty-four hemodynamic monitorings were performed in rabbits sedated by pentobarbital infusion (5 ...
Tang T Y - - 2007
OBJECTIVES: Local anaesthetic infiltration into the carotid sinus during carotid endarterectomy (CEA) has been recommended to minimise blood pressure fluctuations but its use remains controversial. The aim of this meta-analysis was to determine whether intra-operative administration of local anaesthetic reduces the incidence of haemodynamic instability following CEA. MATERIALS AND METHODS: ...
Kolachalama Vijaya B - - 2007
A diagnostic technique is proposed to identify patients with carotid stenosis who could most benefit from angioplasty followed by stent implantation. This methodology involves performing a parametric study to investigate the haemodynamic behavior due to alterations in the stenosis shapes in the internal carotid artery (ICA). A pulsatile 1-D Navier-Stokes ...
Eguchi Kazuo - - 2007
The authors investigated the associations between target organ damage and individual components of the metabolic syndrome (MS) compared with the MS itself. Carotid intima-media thickness (IMT), carotid plaque, and left ventricular mass index (LVMI) were assessed by ultrasonography in 356 participants who were free of overt cardiovascular disease. Participants with ...
Augst A D - - 2007
BACKGROUND: Previous clinical studies have observed relationships between increased intima-media thickness (IMT) in the carotid artery, elevated blood pressure, and low wall shear stress (WSS) calculated from the Poiseuille equation. This study used numerical methods to more accurately determine WSS in the carotid artery and to investigate possible determinants of ...
Bud'ko S L - - 2007
We report measurements of thermal expansion on a number of polycrystalline Cu(x)TiSe(2) samples corresponding to the parts of x-T phase diagram with different ground states, as well as the pressure dependence of the superconducting transition temperature, T(c), for samples with three different values of Cu doping. Thermal expansion data suggest ...
Yang Xiao-zheng - - 2007
BACKGROUND: Atherosclerosis as a cardiovascular disease was found to begin even in the fetal period. However, information about risk factors of pre-clinical atherosclerosis in childhood has been limited. Hence, this study was aimed to find out the risk factors of atherosclerosis by measuring the carotid artery intima-media thickness in children. ...
van Houwelingen Marc J - - 2007
The blood pressure waveform carries information about the cardiac contraction and the impedance characteristics of the vascular bed. Here, we demonstrate that the start of isovolumic ventricular contraction is persistently reflected as an inflection point in the pressure wave as recorded in the aortic root (TP(IC)) as well as in ...
Marfella Raffaele - - 2007
Whether morning blood pressure surge influences the molecular mechanisms of plaque progression toward instability is not known. Recently, we have demonstrated enhanced activity of the ubiquitin-proteasome system in human plaques and evidenced that it is associated with inflammatory-induced plaque rupture. We evaluated the inflammatory infiltration and ubiquitin-proteasome activity in asymptomatic ...
Toorop R J - - 2007
The carotid sinus syndrome (CSS) is characterized by repetitive syncope due to prolonged heart rate slowing or a profound drop in systolic blood pressure. CSS is due to an inappropriate response of a hypersensitive carotid sinus following pressure on or stretching of the neck. We report on a patient with ...
Arima H - - 2007
In order to examine the pressure-induced structural change of liquid silver iodide (AgI), high-pressure and high-temperature in situ x-ray absorption fine structure (XAFS) and x-ray diffraction (XRD) studies have been carried out up to 1200 K and 6 GPa. The modifications in the x-ray absorption near edge structure (XANES) spectra and x-ray ...
Hara Azusa - - 2007
OBJECTIVE: To investigate carotid atherosclerosis in individuals with masked hypertension (MHT) and white-coat hypertension (WCHT) in a general population. METHODS: Self-measurement of blood pressure at home (HBP) and casual blood pressure (CBP) measurements were recorded in 812 individuals aged at least 55 years (mean 66.4 years) from the general Japanese ...
Lin David - - 2007
BACKGROUND: Inappropriate sinus tachycardia (IST) is characterized by heart rate (HR) increase out of proportion to stress level. Radiofrequency (RF) modification of the sinus node (SN) is an accepted treatment modality for medically refractory IST. We describe a new technique using noncontact mapping and a saline irrigated catheter for SN ...
Sugawara Jun - - 2007
OBJECTIVE: Increased aortic and carotid arterial augmentation index (AI) has been directly linked with cardiovascular disease risk, mortality and morbidity. The aim of this study was to examine whether AI obtained directly from radial artery pressure waveforms (radial AI) can provide information comparable with carotid arterial AI measurements. METHODS: In ...
Hans Sachinder Singh - - 2007
This study attempted to correlate neurologic changes in awake patients undergoing carotid endarterectomy (CEA) under cervical block anesthesia (CBA) with electroencephalography (EEG) and measurement of carotid artery stump pressure (SP). Continuous EEG and SP monitoring was measured prospectively in 314 consecutive patients undergoing CEA between April 1, 2003, and July ...
Duarte D P F - - 2007
The aim of this study was to elucidate the role of the baroreflex in blood pressure control in sloths, Bradypus variegatus, since these animals show labile levels in this parameter. Unanesthetized cannulated sloths were positioned in an experimental chair and the arterial catheter was coupled to a strain gauge pressure ...
Cooper Victoria L - - 2007
Variability of blood pressure is limited by arterial baroreceptors, yet blood pressure still shows circadian changes. This study was undertaken to examine if the responses to the carotid baroreflex also change throughout the day. Responses of cardiac interval (RR), mean arterial pressure (MAP) and vascular resistance (VR) to carotid baroreflex ...
Kahraman Goksel - - 2007
BACKGROUND: Although different populations were examined for the incidence of aspirin resistance, the frequency and related risk factors for aspirin resistance in patients with metabolic syndrome have not been reported yet. This study aimed to determine the frequency of aspirin resistance and its risk factors in patients with metabolic syndrome. ...
Cooper V L - - 2007
Obstructive events during sleep in patients with obstructive sleep apnoea (OSA) cause large alterations in blood pressure, and this may lead to changes in baroreflex function with implications for long-term blood pressure control. This study examined the daytime variations in the responses to carotid baroreceptor stimulation in OSA patients. We ...
Turk A S - - 2007
BACKGROUND AND PURPOSE: Noninvasive assessment of the hemodynamic significance of carotid stenosis is often performed with MR angiography and supplemented with carotid Doppler sonography. Phase contrast with vastly undersampled isotropic projection reconstruction (PC-VIPR), a novel MR imaging technique, accelerates phase-contrast MR flow imaging and provides both images of the vessels ...
Chen Xiaoxiao X Department of Electrical and Computer Engineering, Michigan State University, East Lansing, MI 48824, USA. - - 2007
We have previously proposed a technique for estimating the static gain values and impulse response of the arterial and cardiopulmonary total peripheral resistance (TPR) baroreflex by mathematical analysis of beat-to-beat fluctuations in arterial blood pressure, cardiac output, and stroke volume. In this study, we evaluated the technique with respect to ...
Kato K - - 2006
PURPOSE: To evaluate the correlation of stump pressure during balloon occlusion test and relative cerebral blood flow (relative CBF) as measured by 99mTc-hexamethylpropyleneamine oxime (99mTc-HMPAO) single-photon emission computed tomography (SPECT) after test occlusion. MATERIAL AND METHODS: Balloon occlusion test of the internal carotid artery (ICA) was performed in 25 patients. ...
Illig Karl A - - 2006
A large number of patients have hypertension that is resistant to currently available pharmacologic therapy. Electrical stimulation of the carotid sinus baroreflex system has been shown to produce significant chronic blood pressure decreases in animals. The phase II Rheos Feasibility Trial was performed to assess the response of patients with ...
Pugovkin A P - - 2006
The type and degree of blood pressure changes in cats were studied in acute experiments under conditions of acute hypoxic hypoxia (40% decrease in oxygen partial pressure). During hypoxia, blood pressure increased in cats with pressor type of the carotid sinus reflex and decreased in animals with depressor type of ...
Morgan Andrew J - - 2007
The calculation of impedance for a vascular network is a common method used in circulation studies. Impedance indices (the ratios of the harmonics of pressure to the harmonics of flow) provide the investigator with a measure of the opposition to blood flow in a pulsatile system and are a proven ...
Honzikova Natasa - - 2006
We investigated whether body mass index and blood pressure have an additive influence on the carotid intima-media thickness (IMT). In 27 patients treated for hypertension (47.2+/-8.7 years) and 23 normotensive subjects (44.1+/-8.1 years), 24-h recording of blood pressure was performed. The carotid IMT was determined by ultrasonography and baroreflex sensitivity ...
Agostinucci James - - 2006
The purposes of this study were to investigate the effects of circumferential pressure on flexor carpi radialis (FCR) H-reflex in subjects without neuromuscular deficits and to evaluate the skin's contribution to this effect. FCR H-reflex was assessed in 43 subjects by measuring the peak-to-peak amplitude change before, during, and after ...
Filippone J D - - 2006
Hypertension is a major cause of morbidity and mortality worldwide. Despite a myriad of oral agents, many patients fail to reach their target blood pressure. Electrical stimulation of the carotid sinus, an old therapeutic concept, lowers blood pressure by initiating the baroreflex and reducing sympathetic tone. Recent evidence suggests that ...
Levenson Jaime - - 2007
BACKGROUND: Enhanced external counterpulsation (EECP) is a noninvasive method previously shown to improve measures of myocardial ischemia in patients with coronary artery disease. However, the concomitant effects of EECP on large and small arterial properties have been poorly examined. In a randomized controlled study, we investigated whether arterial stiffness and ...
Keller David M DM Institute for Exercise and Environmental Medicine, 7232 Greenville Avenue, Dallas, TX 75231, - - 2006
Prior studies investigating carotid baroreflex control of the cutaneous vasculature have yielded mixed findings. However, previously used methodological and analytical techniques may limit the ability to detect carotid baroreflex-mediated changes in cutaneous vascular conductance (CVC). The aim of this study was to test the hypothesis that dynamic carotid baroreceptor stimulation ...
Haubrich C - - 2007
BACKGROUND: As a sensitive and convenient means for the cerebral hemodynamic monitoring, dynamic cerebral autoregulation testing could be especially useful in medical conditions where less invasive diagnostics and therapies are preferred. This study analysed the effect of carotid stenting on dynamic autoregulation in elderly patients focussing on the relation between ...
Sun Liling - - 2006
Silane (SiH(4)) has been studied in a diamond anvil cell from 7-210 GPa by using optical reflection and absorption techniques at 300 K. The reflectivity and transmission measurements showed a dramatic change in the neighbourhood of 100 GPa. On the basis of reflectivity and absorption experimental data, the pressure dependence of the refractive ...
Tafil-Klawe M - - 2006
The aim of this study was to evaluate the cardiovascular response to the activation of arterial chemoreceptors during voluntary apnea in snoring subjects. Fifty five men were enrolled in the study: 33 snorers and 22 non-snorers (control group). The majority of snorers were overweight and hypertensive. The experimental session consisted ...
Goodman Len S - - 2006
INTRODUCTION: The push-pull maneuver (PPM) is defined as a reduction in G-tolerance when positive acceleration (+Gz) immediately follows negative acceleration (-Gz) exposure, with the carotid baroreceptors presumably playing a dominant role in the ensuing BP (SBP) responses. The objective of this study was to determine whether application of neck pressure ...
Koike Marcia K - - 2006
1. In chronic hypertension, the baroreceptors reset to hypertensive levels with a decrease in gain sensitivity, but only a few studies have evaluated baroreceptor resetting during chronic hypotension and, under these conditions, no consistent information is available concerning changes in baroreceptor gain sensitivity. Therefore, in the present study, the aortic ...
Jastrzebski Marek - - 2006
INTRODUCTION: Inflammatory markers have been reported to be elevated in hypertension. AIM: We compared levels of inflammatory markers between hypertensives (HT) with target organ damage (TOD) but without associated clinical conditions (ACC), n=55, HT with ACC, n=42, HT without TOD/ACC, n=22 and normotensive controls, n=41. METHODS: Serum levels of CRP, ...
Adji Audrey - - 2006
OBJECTIVE: To evaluate the clinical use of radial and carotid artery applanation tonometry as an independent supplement to cuff sphygmomanometry. METHODS: In 44 patients, radial and carotid tonometric pressure recordings were taken at short intervals apart by two persons who had prolonged experience with both. Comparisons were made between directly ...
Yasuda Naohiko - - 2006
The piezoelectric properties of a Pb[(Mg(1/3)Nb(2/3))(0.68)]Ti(0.32)O(3) binary system single crystal poled along the [001] direction in the rhombohedral phase were investigated under pressures up to 400 MPa at 25 °C. For the transverse electromechanical property, the difference Δf between the resonance f(r) and antiresonance frequencies f(a), the Δf/f(r) and the electromechanical coupling ...
Wang Li - - 2006
Using molecular dynamics simulation with the embedded atom method, the structural properties of liquid NiAl in a pressure range of 0-20 GPa are investigated with a quenching rate of 2 K ps(-1). Not only is vitrification of liquid at low temperature detected, but also crystallization by change of average atomic volume as a ...
Yang Minghao - - 2006
The characteristics of baroreceptor firing patterns were recognized in experiment, and their dynamics revealed in theoretical analysis. During blood pressure elevation, baroreceptors gradually exhibited bursting, continuous firing, and paradoxical bursting patterns. The bursting was generated through the repeated bifurcations between rest and spiking, the continuous firing was maintained without bifurcation, ...
Murase Yosuke - - 2006
This study evaluated the compliance and stiffness of decellularized canine common carotid artery as well as decellularized canine ureter and compared it with that of polytetrafluoroethylene, elastin gel combined with polylactic acid tube, and canine common carotid artery. To calculate the compliance and stiffness, internal diameters and cross-sectional areas were ...
Mitchell Graham - - 2006
Using a mechanical model of the giraffe neck and head circulation consisting of a rigid, ascending, 'carotid' limb, a 'cranial' circulation that could be rigid or collapsible, and a descending, 'jugular' limb that also could be rigid or collapsible, we have analyzed the origin of the high arterial and venous ...
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