Van C. Mow

Bio: Van C. Mow is an academic researcher from Columbia University. The author has contributed to research in topics: Cartilage & Viscoelasticity. The author has an hindex of 104, co-authored 265 publications receiving 37196 citations. Previous affiliations of Van C. Mow include Rensselaer Polytechnic Institute & NewYork–Presbyterian Hospital.

A triphasic theory for the swelling and deformation behaviors of articular cartilage.

Abstract: Swelling of articular cartilage depends on its fixed charge density and distribution, the stiffness of its collagen-proteoglycan matrix, and the ion concentrations in the interstitium. A theory for a tertiary mixture has been developed, including the two fluid-solid phases (biphasic), and an ion phase, representing cation and anion of a single salt, to describe the deformation and stress fields for cartilage under chemical and/or mechanical loads. This triphasic theory combines the physico-chemical theory for ionic and polyionic (proteoglycan) solutions with the biphasic theory for cartilage. The present model assumes the fixed charge groups to remain unchanged, and that the counter-ions are the cations of a single-salt of the bathing solution. The momentum equation for the neutral salt and for the intersitial water are expressed in terms of their chemical potentials whose gradients are the driving forces for their movements. These chemical potentials depend on fluid pressure p, salt concentration c, solid matrix dilatation e and fixed charge density cF. For a uni-uni valent salt such as NaCl, they are given by mu i = mu io + (RT/Mi)ln[gamma 2 +/- c(c + cF)] and mu w = mu wo + [p-RT phi (2c + cF) + Bwe]/pwT, where R, T, Mi, gamma +/-, phi, pwT and Bw are universal gas constant, absolute temperature, molecular weight, mean activity coefficient of salt, osmotic coefficient, true density of water, and a coupling material coefficient, respectively. For infinitesimal strains and material isotropy, the stress-strain relationship for the total mixture stress is sigma = - pI-TcI + lambda s(trE)I + 2 musE, where E is the strain tensor and (lambda s, mu s) are the Lame constants of the elastic solid matrix. The chemical-expansion stress (-Tc) derives from the charge-to-charge repulsive forces within the solid matrix. This theory can be applied to both equilibrium and non-equilibrium problems. For equilibrium free swelling problems, the theory yields the well known Donnan equilibrium ion distribution and osmotic pressure equations, along with an analytical expression for the "pre-stress" in the solid matrix. For the confined-compression swelling problem, it predicts that the applied compressive stress is shared by three load support mechanisms: 1) the Donnan osmotic pressure; 2) the chemical-expansion stress; and 3) the solid matrix elastic stress. Numerical calculations have been made, based on a set of equilibrium free-swelling and confined-compression data, to assess the relative contribution of each mechanism to load support. Our results show that all three mechanisms are important in determining the overall compressive stiffness of cartilage.

3D bioprinting of tissues and organs

Abstract: Additive manufacturing, otherwise known as three-dimensional (3D) printing, is driving major innovations in many areas, such as engineering, manufacturing, art, education and medicine. Recent advances have enabled 3D printing of biocompatible materials, cells and supporting components into complex 3D functional living tissues. 3D bioprinting is being applied to regenerative medicine to address the need for tissues and organs suitable for transplantation. Compared with non-biological printing, 3D bioprinting involves additional complexities, such as the choice of materials, cell types, growth and differentiation factors, and technical challenges related to the sensitivities of living cells and the construction of tissues. Addressing these complexities requires the integration of technologies from the fields of engineering, biomaterials science, cell biology, physics and medicine. 3D bioprinting has already been used for the generation and transplantation of several tissues, including multilayered skin, bone, vascular grafts, tracheal splints, heart tissue and cartilaginous structures. Other applications include developing high-throughput 3D-bioprinted tissue models for research, drug discovery and toxicology.

Osteoarthritis: New Insights Part 1: The Disease and Its Risk Factors

Abstract: Osteoarthritis is the most common form of arthritis, affecting millions of people in the United States. It is a complex disease whose etiology bridges biomechanics and biochemistry. Evidence is growing for the role of systemic factors (such as genetics, dietary intake, estrogen use, and bone density) and of local biomechanical factors (such as muscle weakness, obesity, and joint laxity). These risk factors are particularly important in weightbearing joints, and modifying them may present opportunities for prevention of osteoarthritis-related pain and disability. Major advances in management to reduce pain and disability are yielding a panoply of available treatments ranging from nutriceuticals to chondrocyte transplantation, new oral anti-inflammatory medications, and health education. This article is part 1 of a two-part summary of a National Institutes of Health conference. The conference brought together experts on osteoarthritis from diverse backgrounds and provided a multidisciplinary and comprehensive summary of recent advances in the prevention of osteoarthritis onset, progression, and disability. Part 1 focuses on a new understanding of what osteoarthritis is and on risk factors that predispose to disease occurrence. It concludes with a discussion of the impact of osteoarthritis on disability. Ann Intern Med. 2000;133:635-646. www.annals.org For author affiliations and current addresses, see end of text.

The Outcome and Repair Integrity of Completely Arthroscopically Repaired Large and Massive Rotator Cuff Tears

Abstract: Background: The impact of a recurrent defect on the outcome after rotator cuff repair has been controversial. The purpose of this study was to evaluate the functional and anatomic results after arthroscopic repair of large and massive rotator cuff tears with use of ultrasound as an imaging modality to determine the postoperative integrity of the repair. Methods: Eighteen patients who had complete arthroscopic repair of a tear measuring >2 cm in the transverse dimension were evaluated at a minimum of twelve months after surgery and again at two years after surgery. The evaluation consisted of a standardized history and physical examination as well as calculation of the preoperative and postoperative shoulder scores according to the system of the American Shoulder and Elbow Surgeons. The strength of both shoulders was quantitated postoperatively with use of a portable dynamometer. Ultrasound studies were performed with use of an established and validated protocol at a minimum of twelve months after surgery. Results: Recurrent tears were seen in seventeen of the eighteen patients. Despite the absence of healing at twelve months after surgery, thirteen patients had an American Shoulder and Elbow Surgeons score of ≥90 points. Sixteen patients had an improvement in the functional outcome score, which increased from an average of 48.3 to 84.6 points. Sixteen patients had a decrease in pain, and twelve had no pain. Although eight patients had preoperative forward elevation to <95°, all eighteen regained motion above shoulder level and had an average of 152° of elevation. At the second evaluation, a minimum of twenty-four months after surgery, the average score, according to the system of the American Shoulder and Elbow Surgeons, had decreased to 79.9 points; only nine patients had a score of ≥90 points, and six patients had a score of ≤79 points. The average forward elevation decreased to 142°. Conclusions: Arthroscopic repair of large and massive rotator cuff tears led to a high percentage of recurrent defects. The minimum twelve-month evaluation showed excellent pain relief and improvement in the ability to perform activities of daily living despite the high rate of recurrent defects; however, at a minimum follow-up of two years, the results deteriorated with only twelve patients who had an American Shoulder and Elbow Surgeons score of ≥80. Level of Evidence: Therapeutic study, Level IV (case series [no, or historical, control group]). See Instructions to Authors for a complete description of levels of evidence.