Blood flow dynamics of one cardiac cycle and relationship to mechanotransduction and trabeculation during heart looping.

Analyses of form-function relationships during heart looping are directly related to technological advances. Recent advances in four-dimensional optical coherence tomography (OCT) permit observations of cardiac dynamics at high-speed acquisition rates and high resolution. Real-time observation of the avian stage 13 looping heart reveals that interactions between the endocardial and myocardial compartments are more complex than previously depicted.

Age-related changes in the aortic valve affect leaflet stress distributions: implications for aortic valve degeneration.

Background And Aim Of The Study: The degeneration of aortic valve leaflets occurs primarily due to high mechanical stresses in zones of leaflet flexion. Aging, which has been identified as a risk factor for degenerative aortic stenosis, is associated with reductions in stretch and in compliance, and an increase in tissue thickness of the leaflet and root. The study aim was to investigate the effects of age-related tissue changes on valve opening dynamics and leaflet stress patterns, and its implications for valve degeneration.

Delivery strategies to target therapies to inflammatory tissue.

Background: Inflammation plays a key role in many chronic disease processes as well as an acute role in injury and wound healing. Various cell types are recruited from the bloodstream to the inflamed site through adhesion molecules, cytokines, chemokines and others.

Objectives: This review examines many drug-targeting strategies that make use of these molecules or signaling pathways, and seeks to describe certain commonalities irrespective of the disease process or agent to be delivered.

Prediction of pressure recovery location in aortic valve stenosis: an in-vitro validation study.

Background And Aim Of The Study: Pressure recovery is a source of discrepancy between Doppler-derived and catheter aortic valve pressure drops. Pressure recovery occurs where the stenotic jet reattaches to the aortic wall. An equation to predict the jet reattachment location has been developed based on the density and viscosity of blood, the velocity in the stenotic jet, and the aortic root and valve areas.

Immuno-targeting of nonionic surfactant vesicles to inflammation.

Niosomes composed of sorbitan monostearate (Span 60), polyoxyethylene sorbitan monostearate (Tween 61), cholesterol, and dicetyl phosphate were conjugated with a purified monoclonal antibody to CD44 (IM7) through a cyanuric chloride (CC) linkage on the polyoxyethylene group of the Tween 61 molecule. Inclusion of small amounts of Tween 61 within the surfactant component of niosomes formed using thin film hydration techniques and sonication did not hamper vesicle stability as compared to Span 60 niosomes. Conjugation was verified by UV absorbance of fluorescently tagged IM7 in non-fluorescing niosomes and fluorescent micrographs.

A role for the cytoskeleton in heart looping.

Over the past 10 years, key genes involved in specification of left-right laterality pathways in the embryo have been defined. The read-out for misexpression of laterality genes is usually the direction of heart looping. The question of how dextral looping direction occurred mechanistically and how the heart tube bends remains unknown.

Development of markers of valve stiffness for prediction of hemodynamic progression of aortic stenosis.

Degenerative aortic valve stenosis is a progressive disease with an unpredictable rate of progression. Early changes in the degenerative process include thickening and stiffening of the leaflets, reflected in altered rates of opening and closing. Methods have been proposed to measure this in vivo and relate it to the rate of disease progression.

Ultrasound enhancement of drug release across non ionic surfactant vesicle membranes.

Nonionic surfactant vesicles (niosomes) have potential applications in targeted drug delivery and imaging because of their ability to encapsulate therapeutic agents and their enhanced uptake by physiological membranes. Ultrasound may be used to mediate delivery non-invasively by altering the niosome membrane structure. Niosomes composed of polyoxyethylene sorbitan monostearate (Tween 61), cholesterol, and dicetyl phosphate were synthesized via a thin film hydration technique.

Effects of aging on the diagnostic assessment of valvular heart disease.

The diagnostic assessment of the severity of valvular heart disease in the older population is impacted by the anatomic and physiologic changes that accompany normal aging and by the interposition of diseases prevalent in the elderly. In this paper, the impact of those changes on the assessment of valvular heart disease will be reviewed. Special attention will be paid to the effects of age and disease on the measurement of the pressure drop and orifice area.

Age-related changes in hemodynamics affecting valve performance.

Degenerative processes result in changes in both the aortic and mitral valves. For example, degenerative changes may lead to significant aortic stenosis or myxomatous mitral valves. Flows through each valve are determined not only by the properties of the valve itself, but also by the properties of proximal and distal chambers, which also undergo changes with age and diseases associated with the elderly, such as hypertension and coronary artery disease.

Effect of three-dimensional valve shape on the hemodynamics of aortic stenosis: three-dimensional echocardiographic stereolithography and patient studies.

Objectives: This study tested the hypothesis that the impact of a stenotic aortic valve depends not only on the cross-sectional area of its limiting orifice but also on three-dimensional (3D) valve geometry.

Background: Valve shape can potentially affect the hemodynamic impact of aortic stenosis by altering the ratio of effective to anatomic orifice area (the coefficient of orifice contraction [Cc]). For a given flow rate and anatomic area, a lower Cc increases velocity and pressure gradient.

Pathophysiology of Hypertension in the Elderly.

The onset and progression of hypertension is associated with alterations in structure, function, and hemodynamics of the heart, vascular system, and other major organs. An understanding of the structural and functional changes in the cardiovascular system associated with this process would allow for early detection and the development of treatment strategies. In this paper, we focus on the anatomic alterations that accompany vascular aging and the resulting cardiovascular dynamics.