To compare the mechanical properties of lower esophageal sphincter (LES) and esophageal circular smooth muscle, force-velocity determinations were made under various physiological conditions. Isotonic and isometric recordings of opossum circular muscle were used to obtain the velocity of shortening and force, respectively, during alterations in: (a) initial muscle length (preload), (b) afterloa...

BACKGROUND AND PURPOSE Contrast extravasation in DSC-MRI potentiates inaccurate and imprecise estimates of glioma rCBV. We tested assertions that preload and postprocessing algorithms minimize this error by comparing Gd-rCBV using permutations of these 2 techniques with criterion standard rCBV using MION, an intravascular agent. MATERIALS AND METHODS We imaged 7 Fisher rats with 9L gliosarcom...

BACKGROUND Prophylactic fluid preloading before spinal anesthesia has been a routine procedure to prevent maternal hypotension during cesarean delivery. Unlike colloid, timing of infusion of crystalloid may be important because of its short stay in intravascular space. We hypothesized that crystalloid loading just after intrathecal injection compared to preload would be more effective in preven...

Vasopeptidase inhibitors are potent new antihypertensive agents. The dual inhibition of ACE and neutral endopeptidase may result in synergistic humoral effects with unique hemodynamic actions. We investigated the hemodynamic and neurohumoral effects of vasopeptidase inhibition in conscious dogs made hypertensive by bilateral renal wrapping and subsequently instrumented for long-term assessment ...

BACKGROUND We have demonstrated that myocardial acceleration during isovolumic contraction (IVA) is a sensitive index of left ventricular contractile function. In this study, we assessed the utility of IVA to measure right ventricular (RV) contractile function. METHODS AND RESULTS We examined 8 pigs by using tissue Doppler imaging of the RV free wall and simultaneous measurements of intravent...

Insufficient energy compensation after a preload (meal, snack, or beverage) has been associated with excess energy intake, but experimental studies have used heterogeneous methodologies, making energy compensation difficult to predict. The aim of this systematic review was to analyze the relative contributions of two key variables, preload physical form and intermeal interval (IMI), to differen...

The effect of pulsatile pulmonary flow after the modified Fontan procedure was examined in a model that simulated the right heart. An inlet overflow tank (preload), axial pulsatile pump, Wind-Kessel model (afterload), and an outlet overflow tank were connected in series. The standard conditions were flow 2.00 l/min with 12 mm Hg preload pressure, 3.0 Wood units resistance, and an outlet overflo...

Umbilical cord clamping at birth has a major impact on an infant's cardiovascular system that varies in significance depending upon whether the infant has commenced breathing. As umbilical venous return is a major source of preload for the left ventricle during fetal life, recent experimental evidence has shown that clamping the umbilical cord severely limits cardiac venous return in the absenc...

This study investigated the relative satiating hierarchy of the four energy-providing macronutrients (fat, carbohydrate (CHO), protein, and alcohol) in lean women. On four separate occasions, the composition of an iso-energetic lunch preload was manipulated in 12 lean (BMI < 25 kg/m2) women. The four treatments comprised a 1-MJ baseline meal and drink (40% fat, 48% CHO, 12% protein) to which wa...

Background. The use of echocardiography in intensive care settings impacts decision making. A prerequisite for the use of echocardiography is relative resistance to changes in volume status and levels of positive pressure ventilation (PPV). Studies on indices of diastolic function report conflicting results with regard to dependence on volume status. Evidence is scarce on PPV. Methods. Ten heal...