BACKGROUND The Bramwell-Hill model describes the relation between vascular wall stiffness expressed in aortic distensibility and the pulse wave velocity (PWV), which is the propagation speed of the systolic pressure wave through the aorta. The main objective of this study was to test the validity of this model locally in the aorta by using PWV-assessments based on in-plane velocity-encoded card...

In dogs anesthetized with chloralose, innervated loops of intestine were isolated so as to permit periodic interruptions of blood flow to record pressure-volume diagrams from the venous bed. Pressor reflexes were found to produce alterations in the venous distensibility diagrams which, on the basis of comparison with distensibility changes produced by constrictor drugs, are interpreted as direc...

IN clinical ophthalmology the intra-ocular pressure can rarely be determined directly, and reliance must be placed on measurements of the tension of the coats of the eye. The instruments used for the estimation of ocular tension (tonometers) measure the depth of indentation of the, globe produced by a known weight. The depth of indentation depends on several factors, the most important of which...

BACKGROUND AND OBJECTIVES This study aimed to evaluate the transverse and longitudinal distensibility of the posterior human lumbar dura mater. Results are compared with previous literature on biomechanical property studies. Possible clinical implications were also examined. METHODS Samples of human dural sac were obtained from autopsy studies in three adult male cadavers. Dural sac samples w...

We characterized the in vivo mechanical properties of segments of upper descending thoracic aorta (UDTA) in terms of volume distensibility, which was derived from measurements of pulsatile intravascular pressure, inner wall radius, and length changes. Data for this analysis were obtained from six dogs at rest and during moderate treadmill exercise (8% grade, 4.5 miles/hr). Volume distensibility...

The purpose of this study was to determine the effect of dietary Mg deficiency (80 mg/kg versus control diet: 960 mg/kg) on blood pressure and mechanical properties of the rat common carotid artery. The internal diameter and intra-arterial pressure of carotid artery were measured continuously with an echo-tracking device. At 19 weeks, systolic, diastolic, and mean blood pressures were higher in...

Almitrine improves blood gas values in patients with COPD, primarily through better ventilation-perfusion matching. The improvement comes largely from a vasomotor effect of the drug. The vasomotor mechanism is unknown. We suspected that decreased distensibility of the large pulmonary arteries was one probable effect of the drug. If present, reduced distensibility would explain many of the hemod...

Arterial function and wall mechanical properties are important determinants of hemodynamics in the circulation. However, their non-invasive determination is not widely available. Therefore, aim this work to present a novel approach for vessel’s distensibility elastic modulus. Simultaneous measurements Diameter (D) flow velocity (U) were recorded determine local wave speed (nC) flexible tubes ca...

Abstract Chronic kidney disease (CKD) is characterized by clustered age-independent concentric LV geometry, geometry-independent systolic dysfunction, and age heart rate-independent diastolic dysfunction. Concentric geometry always associated with echocardiographic markers of abnormal relaxation increased myocardial stiffness, two hallmarks Non hemodynamic mechanisms such as metabolic electroly...

BACKGROUND AND PURPOSE Arterial stiffening is associated with hypertension, stroke, and cognitive decline; however, the effects of aging and cardiovascular disease risk factors on carotid artery stiffening have not been assessed prospectively in a large multiethnic longitudinal study. METHODS Distensibility coefficient and the Young's elastic modulus (YEM) of the right common carotid artery w...