As a means of assessing ventricular performance, we analyzed the time-varying ratio instantaneous pressure, P(t), to volume, V(t), in canine left ventricle. Intraventricular volume was measured by plethysmography, while right heart totally bypassed. The cardiac nerves were sectioned, and an epinephrine infusion used alter contractile state. pressure-volume defined as E(t) = P(t)/[V(t) - V d ], where is experimentally determined correction factor. We found that (1) all curves thus similar...

We have previously shown in the normally ejecting canine left ventricle that E ( t ), time-varying ratio of instantaneous pressure, P to volume, V is little affected by end-diastolic volume or aortic pressure. The present study on an excised, supported heart preparation indicates thesis ) also valid for either totally isovolumic auxobaric beats. Intraventricular was measured more accurately than it previous a new volumetric system. Regression analysis data showed pressure-volume relationship...

Mechanical energy (ENG) required by a time-varying elastance model of the ventricle was compared with oxygen consumption per beat (VO2) canine left contracting under variety loading conditions. ENG needed for this to increase its during systole is shown be equal sum potential built in plus external mechanical stroke work. This equivalent area (PVA) bounded end-systolic and end-diastolic P-V curves systolic limb loop trajectory plane. There high correlation (r = 0.89) between VO2s documented...

We analyzed the effect of positive inotropic agents on relation between left ventricular oxygen consumption and systolic pressure-volume area. Pressure-volume area is a measure total mechanical energy for contraction, specific in diagram circumscribed by end-systolic end-diastolic curves segment trajectory. Either epinephrine (1 microgram/kg per min, iv) or calcium ion (0.03 mEq/kg was administered to canine excised cross-circulated hearts. These increased an index contractility, Emax, slope...

We scrutinized the recently reported correlation between canine left ventricular systolic pressure-volume area (PVA) and cardiac oxygen consumption rate per beat (Vo2) by use of an improved method Vo2 assessment. PVA is specific in (PV) plane bounded end-systolic end-diastolic PV lines segment loop. Different from previous study which Vo2-PVA data isovolumic ejecting contractions were pooled for analyses, we analyzed two different modes separately to examine whether there was any difference...

Phosphonium salts exhibit great utility in organic synthesis. However, tetraarylphosphonium (TAPS) have found limited use as catalysts. We demonstrate the TAPS-catalyzed carbon dioxide fixation at atmospheric pressure for coupling reaction with epoxides. Five-membered cyclic carbonates were obtained, including enantio-enriched carbonates. Mechanistic studies revealed origin of behavior TAPS to be situ formation an active species by addition epoxides via halohydrin intermediates.

Effects of changes in atrial compliance on cardiac performance were analyzed using a circulatory analog model. The atrium was assumed to be noncontracting chamber with constant compliance. It connected the venous return system, which represented by mean filling pressure and resistance accordance Guyton's concept, ventricle, characterized time-varying elasticity. Atrial increased from near zero value at volume twice ventricular stroke volume, while parameters contractility kept unchanged....

A variable, e(t)=p(t)/v(t), is proposed for formulating the ventricular pumping of blood, as a concept reciprocal compliance, where t=time, p(t)=time course intraventricular pressure and v(t)=that volume. For actual computation, e(t)=p(t)/{v(o)-∫toi(t)dt} v(o)=v(t) at t=o or enddiastolic volume i(t)=aortic blood flow. v(o)=(1-ρ)-1•vs, ρ=residual ratio measured by thermodilution method vs=stroke integral i(t) in cardiac cycle. e(t) calculated areflexive left ventricles dogs under various v(o)...

To gain insight into the pathogenesis of diabetic cardiomyopathy, we investigated cardiac function in terms coupling left ventricular mechanical work and energetics Otsuka Long-Evans Tokushima Fatty rats, which are well known as a model type 2 diabetes mellitus (DM). Neither systolic mean coronary flow nor reserve differed even late DM rats. The amount oxygen required for contraction was unaltered, although myosin isozyme finally transformed from V 1 to 3 . maximum pacing rate decreased 300...

Background The time constant of left ventricular (LV) relaxation derived from a monoexponential model has been widely used as an index LV rate or lusitropism, although this several well-recognized problems. In the present study, we proposed logistic and “logistic” ( T L ) better alternative to conventional “exponential” E ). Methods Results A total 189 beats (147 isovolumic 42 ejecting beats) were investigated in seven canine excised cross–circulated heart preparations. We found that fitted...

We have found the first example of high levels asymmetric induction (97−74% ee) along with diastereoselectivity (>99:1−64:36) in dipole-HOMO-/dipolarophile-LUMO-controlled 1,3-dipolar cycloaddition reactions between fused azomethine imines and 3-acryloyl-2-oxazolidinone using a chiral BINIM−Ni(II) complex as Lewis acid catalyst.

We studied the effects of ventricular end-systolic elastance (Ees) and effective arterial (Ea) on efficiency energy transfer from pressure-volume area (PVA) to external mechanical work (EW) in left ventricle anesthetized closed-chest dogs. PVA represents total generated by contraction, which is an intermediate form between oxygen consumption, input, EW, output. EW were determined pressure volume, continuously measured with a volumetric conductance catheter. Measurements Ees obtained...

A left-ventricular pumping model based on a systolic time-varying pressure/volume ratio e(t) has been proposed the basis of physiological studies indicating that parameter is function time in systole, almost independent from volume and arterial-loading conditions, good index myocardial inotropism. The formulated by following two equations: \begin{equation} p(t) = { v(0)- ∫ <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">t&lt;\sup&gt;₀...

Left ventricle systolic pressure-volume area (PVA) has been found to be highly linearly correlated with cardiac oxygen consumption rate per beat (VO2) in a given canine heart stable inotropic background. PVA is specific the (P-V) diagram that bounded by end-systolic and end-diastolic P-V relationship lines segment of loop, consisting sum external mechanical work what considered elastic potential energy ventricular wall. In this study, we compared VO2's steady state entirely isovolumic...

Left ventricular systolic pressure-volume area (PVA) has been reported to be a reliable predictor of cardiac oxygen consumption rate per beat (VO2) in given heart with stable inotropic background. PVA is the specific (PV) diagram, consisting (EW) within PV loop and (PE) bound by end-systolic end-diastolic lines relaxation segment loop. EW PE correspond external mechanical work elastic potential energy wall, respectively. We determined optimal combination for best prediction VO2, using linear...

Preparation of a range oxazolidinones, including enantioenriched N-aryl-substituted in which tetraarylphosphonium salts (TAPS) catalyze the [3 + 2] coupling reaction isocyanates and epoxides effectively, is described. The key finding Brønsted acid/halide ion bifunctional catalyst that can accelerate epoxide ring opening with high regioselectivity. Mechanistic studies disclosed ylide generated from TAPS, along formation halohydrins, plays crucial role isocyanates.

We have found that significant levels of enantioselectivity are obtained in the 1,3-dipolar cycloadditions 2-benzopyrylium-4-olate using chiral 2,6-bis(oxazolinyl)pyridine (Pybox)-rare earth metal triflate complexes as Lewis acid catalysts. The reactions with benzyloxyacetaldehyde derivatives catalyzed by Sc(III)-Pybox-i-Pr (10 mol %) proceeded to give endo-adducts selectively high (up 93% ee). reaction benzyl pyruvate under similar conditions gave an exo-adduct 87% ee. In...

Recent studies have shown that myocardial oxygen consumption does not proportionally decrease with the deterioration of contractile function in stunned myocardium. To investigate this disproportion, we studied end-systolic pressure-volume relation and between per beat (VO2) systolic area (PVA, a measure total mechanical energy) hearts. In VO2-PVA relation, VO2 can be divided into PVA-dependent PVA-independent fractions. excised cross-circulated dog left ventricles, 15-minute normothermic...

We studied the effects of cardiac cooling by 7 +/- 2 degrees C (SD) from 36 on both contractility index (Emax) and relation between O2 consumption per beat (VO2) systolic pressure-volume area (PVA) left ventricle in excised cross-circulated dog heart preparation. PVA represents total mechanical energy generated a contraction. The VO2-PVA divides measured VO2 into unloaded excess VO2. slope inversely efficiency contractile machinery to convert chemical energy. Cooling is known decrease myosin...