Norizadeh Abbariki Tannaz^*,†, Shokrgozar Mohammad Ali^†,‡, Haghighipour Nooshin^*,§, Aghdami Nasser^¶, Mahdian Rezak^II, Amanzadeh Amir^*, Jazayeri Maryam^*,†

Molecular & Cellular Biomechanics, Vol.11, No.1, pp. 19-37, 2014, DOI:10.3970/mcb.2014.011.019

Abstract Background: Environmental factors affect stem cell differentiation. In addition to chemical factors, mechanical signals have been suggested to enhance myogenic differentiation of stem cells. Therefore, this study was undertaken to illustrate and compare the effect of chemical and mechanical stimuli on Myogenin (MyoG) and Myosin heavy chani 2 (Myh2) expression of mouse bone marrowderived mesenchymal stem cells (BMSCs) and embryonic stem cells (ESCs). Methods: After isolation and expansion of BMSCs and generation of embryoid bodies and spontaneous differentiation of ESCs, cells were examined in 4 groups: (1) control group: untreated cells; (2) chemical group: cells incubated in myogenic medium (5-azacythidine… More >

JA. Herzog^∗, TR. Leonard^†, A. Jinha^†, W. Herzog^†,‡

Molecular & Cellular Biomechanics, Vol.11, No.1, pp. 1-17, 2014, DOI:10.3970/mcb.2014.011.001

Abstract Titin is the third most abundant protein in sarcomeres and fulfills a number of mechanical and signaling functions. Specifically, titin is responsible for most of the passive forces in sarcomeres and the passive visco-elastic behaviour of myofibrils and muscles. It has been suggested, based on mechanical testing of isolated titin molecules, that titin is an essentially elastic spring if Ig domain un/refolding is prevented either by working at short titin lengths, prior to any unfolding of Ig domains, or at long sarcomere (and titin) lengths when Ig domain un/refolding is effectively prevented. However, these properties of titin, and by extension… More >

G. Geethanjali^∗, C. Sujatha^†

Molecular & Cellular Biomechanics, Vol.10, No.4, pp. 303-317, 2013, DOI:10.3970/mcb.2013.010.303

Abstract This paper reports a study on the biomechanical response of a human hand-arm model to random vibrations of the steering wheel of a tractor. An anatomically accurate bone-only hand-arm model from TurboSquidTM was used to obtain a finite element (FE) model to understand the Hand-arm vibration syndrome (HAVS), which is a neurological and vascular disorder caused by exposure of the human hand-arm to prolonged vibrations. Modal analysis has been done to find out the first few natural frequencies and mode shapes of the system. Coupling of degrees of freedom (DOF) had to be done in the FE idealization to do… More >

Annette Doyle^*, Steven R. Crosby^†, David R. Burton^*, Francis Lilley^*, Gary Johnston^*, Winder B. Perez^‡, Terri G. Kinzy^‡, Mark F. Murphy^*,†,§

Molecular & Cellular Biomechanics, Vol.10, No.4, pp. 275-288, 2013, DOI:10.3970/mcb.2013.010.275

Abstract Many diseases including cancer are associated with a disorganised cytoskeleton. The process of characterising how cytoskeletal disorganisation affects the mechanical properties of cells offers the potential to develop new drugs and treatment regimes that may exploit mechanical weakness in cells and tissues. This work investigated the role of actin associated proteins, namely tropomyosin 1 (tpm1p) and mitochondrial distribution and morphology protein 20 (mdm20p), on the mechanical and morphological properties of yeast cells. For the first time it was shown that deletion of both the TPM1 and MDM20 genes resulted in a decrease in Young’s modulus when compared to the wild-type… More >

Syed A Jamal^*

Molecular & Cellular Biomechanics, Vol.10, No.4, pp. 267-273, 2013, DOI:10.3970/mcb.2013.010.267

Abstract Human Umbilical Cord Mesenchymal Stem Cells (hUCMSCs) were subjected to in vitro osteogenic differentiation using a novel combination of signaling molecules including BMP-2 and purmorphamine. Differentiation outcomes were assessed by calcein staining and by microscopic examination of the cytoskeleton. Calcein staining showed appreciable degree of calcium mineralization in cell culture, and changes in the morphological attributes of differentiating cells were observed vis-a-vis the actin cytoskeleton. Finally, positive calcein staining, altered cytoskeletal profile, and stress fiber formation in treated cells demonstrated, for the first time, a potentially synergistic interplay between BMP-2 and the hedgehog agonist, purmorphamine. This study lends support to… More >

Marek Jasiński^*

Molecular & Cellular Biomechanics, Vol.10, No.3, pp. 183-199, 2013, DOI:10.3970/mcb.2013.010.183

Abstract In the paper the numerical analysis of thermal processes proceeding in the biological tissue is presented. The tissue is subjected to the external heat flux and 2D problem is taken into account. In order to determine the influence of variations of thermophysical parameters of tissue on the value of Arrhenius injury integral the direct approach of sensitivity analysis is applied. On the basis of tissue damage fraction the thermal injury formation process is analysed. At the stage of numerical realization the boundary element method is used. In the final part of the paper the example of numerical simulation is shown. More >

Yongren Wu^∗, Sarah Cisewski^∗, Barton L. Sachs^†, Hai Yao^∗,†,‡

Molecular & Cellular Biomechanics, Vol.10, No.2, pp. 159-182, 2013, DOI:10.3970/mcb.2013.010.159

Abstract This study examines the effects of cartilage endplate (CEP) calcification and the injection of intervertebral disc (IVD) cells on the nutrition distributions inside the human IVD under physiological loading conditions using multiphasic finite element modeling. The human disc was modeled as an inhomogeneous mixture consisting of a charged elastic solid, water, ions (Na⁺ and Cl⁻), and nutrient solute(oxygen,glucose and lactate) phases. The effect of the endplate calcification was simulated by a reduction of the tissue porosity (i.e., water volume faction) from 0.60 to 0.48. The effect of cell injection was simulated by increasing the cell density in the nucleus pulposus… More >

Marco A.Velasco^∗, Diego A. Garzón-Alvarado^†

Molecular & Cellular Biomechanics, Vol.10, No.2, pp. 137-157, 2013, DOI:10.3970/mcb.2013.010.137

Abstract The design of porous scaffolds for tissue engineering requires methods to generate geometries in order to control the stiffness and the permeability of the implant among others characteristics. This article studied the potential of the reaction-diffusion systems to design porous scaffolds for bone regeneration. We simulate the degradation of the scaffold material and the formation of new bone tissue over canal-like, spherical and ellipsoid structures obtained by this approach. The simulations show that the degradation and growth rates are affected by the form of porous structures. The results have indicated that the proposed method has potential as a tool to… More >

Idalba A. Hidalgo A.^∗, Felipe Sojo^†, Francisco Arvelo^†, Marcos A. Sabino^∗,‡

Molecular & Cellular Biomechanics, Vol.10, No.2, pp. 85-105, 2013, DOI:10.3970/mcb.2013.010.085

Abstract The electrospinning technique is a method used to produce nano and microfibers using the influence of electrostatic forces. Porous three dimensional networks of continuous and interconnected fibers as scaffolds were obtained from a poly (lactic acid) solution. The concentration of the polymeric solution, 12.5% m/w, as well as the conditions of voltage (V=11kV) and tip-metallic collector distance (H=13cm) were established to develop these scaffolds through the electrospinning process. The characteristics of the scaffolds, such as fiber diameter, sintering and the biomimetics of the characteristics of a native extra cellular matrix were verified by Scanning Electron Microscopy (SEM). The orientation induced… More >

S.J. Mousavi^∗, M.H. Doweidar^∗,†, M. Doblaré^∗

Molecular & Cellular Biomechanics, Vol.10, No.1, pp. 1-25, 2013, DOI:10.3970/mcb.2013.010.001

Abstract Although there are several computational models that explain the trajectory that cells take during migration, till now little attention has been paid to the integration of the cell migration in a multi-signaling system. With that aim, a generalized model of cell migration and cell-cell interaction under multisignal environments is presented herein. In this work we investigate the spatio-temporal cell-cell interaction problem induced by mechano-chemo-thermotactic cues. It is assumed that formation of a new focal adhesion generates traction forces proportional to the stresses transmitted by the cell to the extracellular matrix. The cell velocity and polarization direction are calculated based on… More >