China Science

Dahl,SL; Rhim,C; Song,YC; Niklason,LE

Abstract With the goal of mimicking the mechanical properties of a given nativetissue, tissue engineers seek to culture replacement tissues with compositions similar to those ofnative tissues. In this report, differences between the mechanical properties of engineered arteriesand native arteries were correlated with differences in tissue composition. Engineered arteriesfailed to match the strengths or compliances of native tissues. (more…)

Alvarez-Barreto,JF; Linehan,SM; Shambaugh,RL; Sikavitsas,VI

Abstract Engineered bone grafts have been generated in static and dynamic systems byseeding and culturing osteoblastic cells on 3-D scaffolds. Seeding determines initial cellularityand cell spatial distribution throughout the scaffold, and affects cell-matrix interactions. Staticseeding often yields low seeding efficiencies and poor cell distributions; (more…)

Tummala,SR; Hall,CL

Abstract Coating surfaces of implanted devices with anticoagulants can reducethrombosis and studies using a recombinant form of endogenous tissue factor pathway inhibitor(rTFPI) are promising. The anticoagulant function of immobilized rTFPI is thought to occur primarilyby its inhibition of plasma clotting factor Xa (FXa); (more…)

Deserranno,D; Kassemi,M; Thomas,JD

Abstract The success and usefulness of lumped cardiovascular models are directlydependent on the physiological fidelity of their formulation. In most existing lumped formulationsfor the heart, the compliance of the chamber is modeled based on its electrical analog, thecapacitor. This has traditionally resulted in the use of a pre-described time-varying stiffnessmodulus for simulating the cardiac contractions. Unfortunately, such a time-varying stiffness doesnot include any physiological contractile machinery and thus no dependency on fiber sarcomere lengthand intracellular calcium concentrations, key mechanisms responsible for proper cardiac function.In this paper a lumped cardiovascular model is presented that is based on the incorporation ofdetailed myofilament activation for simulating the ventricular calcium binding and cross-bridgingmechanism. Upon validation against experimental data, it is shown that the new myofilamentactivation-based model considerably increases the physiological validity andinternal consistency ofthe cardiovascular simulations in comparison to the traditional variable compliance-based models. Itis also shown, through specific case studies, that the present model can serve as a quick responsetool for testing various hypotheses concerning the impact of the calcium binding and crossbridgekinetics on the overall performance of the cardiovascular system.

Keywords Actins; Heart; Microfilaments; Models, Biological

Annals of Biomedical Engineering
0090-6964, Volume 35, Issue 3, 2007, Pages 3-336

Lu,X; Kassab,GS

Abstract The vasoactivity of blood vessel is impaired by cardiovascular disease. Theex-vivo measurements of vasoactivity (wire and pressure myographs) have some inherent difficultiesin the characterization of pharmacodynamics and biomechanics. Here, we introduce a novel isovolumicmyograph which allows simultaneous measurement of both dynamic pressure and dimensional changesduring vasoconstriction or vasodilation. (more…)

Maner,WL; Garfield,RE

Abstract OBJECTIVE: To use artificial neural networks (ANNs) on uterineelectromyography (EMG) data to classify term/preterm labor/non-labor pregnant patients. MATERIALSAND METHODS: A total of 134 term and 51 preterm women (all ultimately delivered spontaneously) wereincluded. Uterine EMG was measured trans-abdominally using surface electrodes. (more…)

Dixon,JB; Gashev,AA; Zawieja,DC; Moore-JE,Jr; Cote,GL

Abstract Efforts have recently been made to estimate wall shear stress throughout thecontractile cycle of mesenteric rat lymphatics with a high speed video microscopy system. This wasprompted by reports in the literature that lymphatic pumping is related to wall shear stress. Whileone can estimate wall shear stress by tracking lymphocyte velocity, it is prohibitively tedious tomanually track particles over a reasonable time frame for a good number of experiments. (more…)

Abstract In biology, specific cell adhesion is mediated by receptor-ligandinteractions. Consequently, its strength correlates with the strength of single receptor-ligandbonds that can be measured with a variety of techniques. However, whether single receptor-ligandbonds are truly present in an experiment is often a concern. In this paper, we present a Monte Carlosimulation of the adhesion between a microvillus-bearing cell and a ligand-coated substrate. (more…)