Wangping Duan^∗, Lei Wei^†, Juntao Zhang^∗, Yongzhuang Hao^∗, Chunjiang Li^∗, Hao Li^∗, Qi Li^∗, Quanyou Zhang^‡, Weiyi Chen^‡, Xiaochun Wei^∗,§

Molecular & Cellular Biomechanics, Vol.8, No.4, pp. 253-274, 2011, DOI:10.3970/mcb.2011.008.253

Abstract The cytoskeleton network is believed to play an important role in the biomechanical properties of the chondrocyte. Ours and other laboratories have demonstrated that chondrocytes exhibit a viscoelastic solid creep behavior in vitro and that viscoelastic properties decrease in osteoarthritic chondrocytes. In this study, we aimed to understand whether the alteration of viscoelastic properties is associated with changes in cytoskeleton components of ageing chondrocytes from rabbit knee articular cartilage. Three age groups were used for this study: young (2-months-old, N=23), adult (8-months-old, N=23), and old (31-months-old, N=23) rabbit groups. Cartilage structure and proteoglycan and type II collagen content were determined… More >

Rami K Korhonen^∗,†, Sang-Kuy Han^‡, Walter Herzog^‡

Molecular & Cellular Biomechanics, Vol.7, No.3, pp. 125-134, 2010, DOI:10.3970/mcb.2010.007.125

Abstract Changes in the osmotic environment cause changes in volume of isolated cells and cells in tissue explants, and the osmotic environment becomes hypotonic in cartilage diseases such as osteoarthritis (OA). However, it is not known how cells respond to a hypotonic osmotic challenge when situated in the fully intact articular cartilage.
A confocal laser scanning microscope was used to image chondrocytes of intact rabbit patellae in an isotonic (300 mOsm) and hypotonic (172 mOsm) immersion medium. Cell volumes were calculated before and 5, 15, 60, 120 and 240 minutes after the change in saline concentration. Local tissue strains and swelling… More >

Yequan Wang^*, Li Yang^*, Jin Zhang^*, Ruyue Xue^*, Zhenyu Tang^*, Wei Huang^†, Dianming Jiang^†, Xinyan Tang^*, Peter Chen^‡, KL Paul Sung^{∗,‡,§,¶}

Molecular & Cellular Biomechanics, Vol.7, No.2, pp. 105-114, 2010, DOI:10.3970/mcb.2010.007.105

Abstract The anterior cruciate ligament, posterior cruciate ligament, cartilage and meniscus in human knee joint have poor healing ability. Accumulation of MMPs in the joint fluids due to knee injury has been considered as the main reason. Our previous experiments showed that synovium may be the major regulator of MMPs in joint cavity after injury. In this paper, we used human synoviocytes harvested from synovium to determine whether mechanical injury and inflammatory factors will induce MMP-2 production in synoviocytes. With zymography, we found that mechanical compression increased the MMP-2 production by 23% under 6% compressions, 61% under 12% compression and 109%… More >

Sangho Kim^∗,†, Peng Kai Ong^*, Paul C. Johnson^‡

Molecular & Cellular Biomechanics, Vol.6, No.2, pp. 83-92, 2009, DOI:10.3970/mcb.2009.006.083

Abstract Recently, we reported that collision efficiency (fraction of total collisions that result in the formation of aggregates) between red blood cells was an important factor in the formation of aggregates in postcapillary venules. In the present study, we focus on how high molecular weight dextran influences the overall radial migration trend of red blood cells in the postcapillary venule along a longitudinal distance of 50 μm from the bifurcation which would in turn affect collision behavior of these cells. A radial migration index, which defines the extent of radial migration of individual cells relative to the vessel center, was found… More >

Chun Yang^∗,†, Dalin Tang^∗,‡, Shunichi Kobayashi^§, Jie Zheng^¶, Pamela K. Woodard^§, Zhongzhao Teng^*, Richard Bach^||, David N. Ku^∗∗

Molecular & Cellular Biomechanics, Vol.5, No.4, pp. 259-274, 2008, DOI:10.3970/mcb.2008.005.259

Abstract Many acute cardiovascular syndromes such as heart attack and stroke are caused by atherosclerotic plaque ruptures which often happen without warning. MRI-based models with fluid-structure interactions (FSI) have been introduced to perform flow and stress/strain analysis for atherosclerotic plaques and identify possible mechanical and morphological indices for accurate plaque vulnerability assessment. In this paper, cyclic bending was added to 3D FSI coronary plaque models for more accurate mechanical predictions. Curvature variation was prescribed using the data of a human left anterior descending (LAD) coronary artery. Five computational models were constructed based on ex vivo MRI human coronary plaque data to… More >

Gretchen J. McAuliffe^*, Jung Yun Chang^†, Raymond P. Glahn^‡, Michael L. Shuler^§

Molecular & Cellular Biomechanics, Vol.5, No.2, pp. 119-132, 2008, DOI:10.3970/mcb.2008.005.119

Abstract Microscale cell culture analogs (μCCAs) are used to study the metabolism and toxicity of a chemical or drug. These in vitro devices are physical replicas of physiologically based pharmacokinetic models that combine microfabrication and cell culture. The goal of this project is to add an independent GI tract μCCA to a multi-chamber chip μCCA representing the primary circulation. The GI tract μCCA consists of two chambers separated by a microporous membrane on which intestinal epithelial cells are cultured. Compounds of interest are pumped through the top chamber, allowing drug to be absorbed through the epithelial layer and circulated into the… More >

Geert W. Schmid-Schönbein^*

Molecular & Cellular Biomechanics, Vol.5, No.2, pp. 83-96, 2008, DOI:10.3970/mcb.2008.005.083

Abstract Increasing evidence suggests that most cardiovascular diseases, tumors and other ailments are associated with an inflammatory cascade. The inflammation is accompanied by activation of cells in the circulation and fundamental changes in the mechanics of the microcirculation, expression of pro-inflammatory genes and downregulation of anti-inflammatory genes, attachment of leukocytes to the endothelium, elevated permeability of the endothelium, and many other events. The evidence has opened great opportunities for medicine to develop new anti-inflammatory interventions. But it also raises a fundamental question: What is the origin of inflammation? I will discuss a basic series of studies that was designed to explore… More >

Meghan H. Hoskins^*, Cheng Dong^∗,†

Molecular & Cellular Biomechanics, Vol.3, No.2, pp. 79-88, 2006, DOI:10.3970/mcb.2006.003.079

Abstract It has been determined previously that polymorphonuclear leukocytes, or PMNs, can facilitate melanoma cell extravasation through the endothelium under shear conditions [1,2]. The interactions between melanoma cells and PMNs are mediated by the β₂-integrins expressed by PMNs and intercellular adhesion molecules (ICAM-1) expressed on melanoma cells. In this study, the kinetics of these interactions was studied using a parallel plate flow chamber. The dissociation rates were calculated under low force conditions for ICAM-1 interactions with both β₂-integrins, LFA-1 (CD11a/CD18) and Mac-1 (CD11b/CD18), together and separately by using functional blocking antibodies on PMNs. The kinetics of PMNs stimulated with IL-8 was… 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 DNA can be well… 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 the EC, subsequent PMN capture… More >