School of Psychology, University of New South Wales, Sydney, NSW 2052, Australia. Now at: School of Psychology, University of Exeter, Washington Singer Building, Perry Road, Exeter EX4 4QG, UK. Acknowledgements The research reported in this manuscript was supported by a UK MRC Grant (G0701456) held by Lee Hogarth whilst at the University of Nottingham UK. The Author would like to thank Amy Inma...

With DSC-MRI, contrast agent leakage effects in brain tumors can either be leveraged for percent signal recovery (PSR) measurements or be adequately resolved for accurate relative cerebral blood volume (rCBV) measurements. Leakage effects can be dimished by administration of a preload dose before imaging and/or specific postprocessing steps. This study compares the consistency of both PSR and r...

Splanchnic nerve stimulation (SNS) mobilizes up to 25% of the total blood volume from the splanchnic venous bed, constricts the splanchnic arterioles, and releases catecholamines and renin. This study examines the effects of these changes on cardiac preload, afterload, and output in cats anesthetized with chloralose. Before adrenalectomy, SNS caused increases in right atrial and arterial pressu...

The objectives of this study were to obtain linearized stiffness matrices, and assess the linearity and hysteresis of the motion segments of the human lumbar spine under physiological conditions of axial preload and fluid environment. Also, the stiffness matrices were expressed in the form of an 'equivalent' structure that would give insights into the structural behavior of the spine. Mechanica...

Dong, Sheng-Jing, Paul S. Hees, Wen-Mei Huang, Sam A. Buffer, Jr., James L. Weiss, and Edward P. Shapiro. Independent effects of preload, afterload, and contractility on left ventricular torsion. Am. J. Physiol. 277 (Heart Circ. Physiol. 46): H1053–H1060, 1999.—Shortening of oblique left ventricular (LV) fibers results in torsion. A unique relationship between volume and torsion is therefore ex...

BACKGROUND Left ventricular contractility in atrial fibrillation is known to change in a beat to beat fashion, but there is no gold standard for contractility indices in atrial fibrillation, especially those measured non-invasively. OBJECTIVE To determine whether the non-invasive index of contractility "preload-adjusted PWR(max)" (maximal ventricular power divided by the square of end diastol...

The effects of acute volume loading were examined on indices of left ventricular (LV) function in conscious, unrestrained and intact, tranquilized baboons. Experiments were conducted 1-3 mo after implantation of ultrasonic transducers to measure LV internal diameter and wall thickness, and miniature LV pressure gauges and aortic and left atrial catheters. In 10 intact, tranquilized baboons, rap...

BACKGROUND To determine how the tissues that surround the heart affect diastolic and systolic function during the perinatal period, we studied the pressure-diameter relation of the left ventricle in partially delivered fetal lambs. METHODS AND RESULTS We anesthetized (1.5-2.0% halothane, balance O2) and ventilated six pregnant ewes (142-144 days of gestation) and then partially delivered each...

Abstract Background Hemodynamic instability is a frequent complication of continuous renal replacement therapy (CRRT). Postural tests (i.e., passive leg raising in the supine position or Trendelenburg maneuver prone position) combined with measurement cardiac output are highly reliable to identify preload-dependence and may provide new insights into mechanisms involved hemodynamic related CRRT ...