Kyle Kurpinski^1,2,3, Jennifer Park^1,2,3, Rahul G. Thakar^1,2,3, Song Li^1,2

Molecular & Cellular Biomechanics, Vol.3, No.1, pp. 21-34, 2006, DOI:10.3970/mcb.2006.003.021

Abstract Vascular smooth muscle cells (SMCs) populate in the media of the blood vessel, and play an important role in the control of vasoactivity and the remodeling of the vessel wall. Blood vessels are constantly subjected to hemodynamic stresses, and the pulsatile nature of the blood flow results in a cyclic mechanical strain in the vessel walls. Accumulating evidence in the past two decades indicates that mechanical strain regulates vascular SMC phenotype, function and matrix remodeling. Bone marrow mesenchymal stem cell (MSC) is a potential cell source for vascular regeneration therapy, and may be used to More >

Jizeng Wang^1,2, Xiaojun Fan², Huajian Gao²

Molecular & Cellular Biomechanics, Vol.3, No.1, pp. 13-20, 2006, DOI:10.3970/mcb.2006.003.013

Abstract This paper is aimed at a combined theoretical and numerical study of the force-extension relation of a short DNA molecule stretched in an electrolyte. A theoretical formula based on a recent discrete wormlike chain (WLC) model of Kierfeld et al. (Eur. Phys. J. E, Vol. 14, pp.17-34, 2004) and the classical OSF mean-field theory on electrostatic stiffening of a charged polymer is numerically verified by a set of Brownian dynamics simulations based on a generalized bead-rod (GBR) model incorporating long-ranged electrostatic interactions via the Debye-Hueckel potential (DH). The analysis indicates that the stretching of a short More >

E. Takai¹, R. Landesberg², R.W. Katz², C.T. Hung³, X.E Guo^1,4

Molecular & Cellular Biomechanics, Vol.3, No.1, pp. 1-12, 2006, DOI:10.3970/mcb.2006.003.001

Abstract Osteoblast interactions with extracellular matrix (ECM) proteins are known to influence many cell functions, which may ultimately affect osseointegration of implants with the host bone tissue. Some adhesion-mediated events include activation of focal adhesion kinase, and subsequent changes in the cytoskeleton and cell morphology, which may lead to changes in adhesion strength and cell responsiveness to mechanical stimuli. In this study we examined focal adhesion kinase activation (FAK), F-actin cytoskeleton reorganization, adhesion strength, and osteoblast responsiveness to fluid shear when adhered to type I collagen (ColI), glass, poly-L-lysine (PLL), fibronectin (FN), vitronectin (VN), and serum… More >

Dhanjoo N. Ghista^1,2, Liang Zhong², Leok P.Chua², Eddie Y-K Ng², Soo T.Lim³, Ru S. Tan³, TerranceS-J Chua³

Molecular & Cellular Biomechanics, Vol.2, No.4, pp. 217-234, 2005, DOI:10.3970/mcb.2005.002.217

Abstract Background: In this paper, the left ventricle (LV) is modeled as a cylinder with myocardial fibers located helically within its wall. A fiber is modeled into myocardial structural units (MSUs); the core entity of each MSU is the sarcomeric contractile element. The relationship between the sarcomere unit's contractile force and shortening velocity is expressed in terms of the LV model's wall stress and deformation, and hence in terms of the monitored LV pressure and volume. Then, the LV systolic performance is investigated in terms of a mechatronic (excitation-contraction) model of the sarcomere unit located within the… More >

S. Deguchi^1,2, T. Ohashi², M. Sato²

Molecular & Cellular Biomechanics, Vol.2, No.4, pp. 205-216, 2005, DOI:10.3970/mcb.2005.002.205

Abstract Intracellular stress transmission through subcellular structural components has been proposed to affect activation of localized mechano-sensing sites such as focal adhesions in adherent cells. Previous studies reported that physiological extracellular forces produced heterogeneous spatial distributions of cytoplasmic strain. However, mechanical signaling pathway involved in intracellular force transmission through basal actin stress fibers (SFs), a mechano-responsive cytoskeletal structure, remains elusive. In the present study, we investigated force balance within the basal SFs of cultured smooth muscle cells and endothelial cells by (i) removing the cell membrane and cytoplasmic constituents except for materials physically attaching to the… More >

Morakot Likhitpanichkul¹, X. Edward Guo², Van C. Mow^1,3

Molecular & Cellular Biomechanics, Vol.2, No.4, pp. 191-204, 2005, DOI:10.3970/mcb.2005.002.191

Abstract Thorough analyses of the mechano-electrochemical interaction between articular cartilage matrix and the chondrocytes are crucial to understanding of the signal transduction mechanisms that modulate the cell metabolic activities and biosynthesis. Attempts have been made to model the chondrocytes embedded in the collagen-proteoglycan extracellular matrix to determine the distribution of local stress-strain field, fluid pressure and the time-dependent deformation of the cell. To date, these models still have not taken into account a remarkable characteristic of the cartilage extracellular matrix given rise from organization of the collagen fiber architecture, now known as the tension-compression nonlinearity (TCN)… More >

Muhammad H. Zaman¹

Molecular & Cellular Biomechanics, Vol.2, No.4, pp. 179-190, 2005, DOI:10.3970/mcb.2005.002.179

Abstract We report the results of longest to date simulation on misfolding of monomeric human prion protein (HuPrP). By comparing our simulation of a partially unfolded protein to the simulation of the native protein, we observe that the native protein as well as native regions in the partially unfolded protein remain in the native state, and the unfolded regions fold back with increased extended (sheet and PP-II) conformations. The misfolded regions show increased basin hopping from non-helical basins while the amino acids locked in the helical conformation tend to stay locked in that conformation. Our results More >

Shouqin Lü¹, Mian Long^1,2

Molecular & Cellular Biomechanics, Vol.2, No.4, pp. 161-178, 2005, DOI:10.3970/mcb.2005.002.161

Abstract Selectin-ligand interactions are crucial to such biological processes as inflammatory cascade or tumor metastasis. How transient formation and dissociation of selectin-ligand bonds in blood flow are coupled to molecular conformation at atomic level, however, has not been well understood. In this study, steered molecular dynamics (SMD) simulations were used to elucidate the intramolecular and intermolecular conformational evolutions involved in forced dissociation of three selectin-ligand systems: the construct consisting of P-selectin lectin (Lec) and epidermal growth factor (EGF)-like domains (P-LE) interacting with synthesized sulfoglycopeptide or SGP-3, P-LE with sialyl Lewis X (sLe^X), and E-LE with sLe^X. SMD… More >

Cheng Dong^1,2,3, Margaret J. Slattery^2,3, Shile Liang³, Hsin-Hsin Peng²

Molecular & Cellular Biomechanics, Vol.2, No.3, pp. 145-160, 2005, DOI:10.3970/mcb.2005.002.145

Abstract Attachment of tumor cells to the endothelium (EC) under flow conditions is critical for the migration of tumor cells out of the vascular system to establish metastases. Innate immune system processes can potentially promote tumor progression through inflammation dependant mechanisms.\nobreakspace {} White blood cells, neutrophils (PMN) in particular, are being studied to better understand how the host immune system affects cancer cell adhesion and subsequent migration and metastasis. Melanoma cell interaction with the EC is distinct from PMN-EC adhesion in the circulation. We found PMN increased melanoma cell extravasation, which involved initial PMN tethering on… More >

A.L. Brock, D.E. Ingber¹

Molecular & Cellular Biomechanics, Vol.2, No.3, pp. 135-144, 2005, DOI:10.3970/mcb.2005.002.135

Abstract The direction in which cells extend new motile processes, such as lamellipodia and filopodia, can be controlled by altering the geometry of extracellular matrix adhesive islands on which individual cells are cultured, thereby altering mechanical interactions between cells and the adhesive substrate [Parker (2002)]. Here we specifically investigate the intracellular molecular signals that mediate the mechanism by which cells selectively extend these processes from the corners of polygonal-shaped adhesive islands. Constitutive activation of the small GTPase Rac within cells cultured on square-shaped islands of fibronectin resulted in the elimination of preferential extension from corners. This… More >