Search

Your search keyword '"VISCOELASTICITY"' showing total 4 results
Start Over Descriptor "VISCOELASTICITY" Topic biological tissue Topic chemical properties Publication Year Range Last 50 years
4 results on '"VISCOELASTICITY"'

1. Viscoelastic parameters as discriminators of breast masses: Initial human study results.

Author

Kumar, Viksit, Denis, Max, Gregory, Adriana, Bayat, Mahdi, Mehrmohammadi, Mohammad, Fazzio, Robert, Fatemi, Mostafa, and Alizad, Azra

Subjects
*SHEAR waves, *ELASTOGRAPHY, *BREAST cancer diagnosis, *SOFT tissue tumors, *VISCOELASTICITY
Abstract

Shear wave elastography is emerging as a clinically valuable diagnostic tool to differentiate between benign and malignant breast masses. Elastography techniques assume that soft tissue can be modelled as a purely elastic medium. However, this assumption is often violated as soft tissue exhibits viscoelastic properties. In order to explore the role of viscoelastic parameters in suspicious breast masses, a study was conducted on a group of patients using shear wave dispersion ultrasound vibrometry in the frequency range of 50–400 Hz. A total of 43 female patients with suspicious breast masses were recruited before their scheduled biopsy. Of those, 15 patients did not meet the data selection criteria. Voigt model based shear elasticity showed a significantly (p = 7.88x10-6) higher median value for the 13 malignant masses (16.76±13.10 kPa) compared to 15 benign masses (1.40±1.12 kPa). Voigt model based shear viscosity was significantly different (p = 4.13x10-5) between malignant (8.22±3.36 Pa-s) and benign masses (2.83±1.47 Pa-s). Moreover, the estimated time constant from the Voigt model, which is dependent on both shear elasticity and viscosity, differed significantly (p = 6.13x10-5) between malignant (0.68±0.33 ms) and benign masses (3.05±1.95 ms). Results suggest that besides elasticity, viscosity based parameters like shear viscosity and time constant can also be used to differentiate between malignant and benign breast masses. [ABSTRACT FROM AUTHOR]

Published
2018
Full Text
View/download PDF

2. Platelet Rich Plasma and Hyaluronic Acid Blend for the Treatment of Osteoarthritis: Rheological and Biological Evaluation.

Author

Russo, Fabrizio, D’Este, Matteo, Vadalà, Gianluca, Cattani, Caterina, Papalia, Rocco, Alini, Mauro, and Denaro, Vincenzo

Subjects
*HYALURONIC acid, *OSTEOARTHRITIS treatment, *ECOLOGICAL assessment, *CARTILAGE, *VISCOELASTICITY
Abstract

Introduction: Osteoarthritis (OA) is the most common musculoskeletal disease. Current treatments for OA are mainly symptomatic and inadequate since none results in restoration of fully functional cartilage. Hyaluronic Acid (HA) intra-articular injections are widely accepted for the treatment of pain associated to OA. The goal of HA viscosupplementation is to reduce pain and improve viscoelasticity of synovial fluid. Platelet-rich plasma (PRP) has been also employed to treat OA to possibly induce cartilage regeneration. The combination of HA and PRP could supply many advantages for tissue repair. Indeed, it conjugates HA viscosupplementation with PRP regenerative properties. The aim of this study was to evaluate the rheological and biological properties of different HA compositions in combination with PRP in order to identify (i) the viscoelastic features of the HA-PRP blends, (ii) their biological effect on osteoarthritic chondrocytes and (iii) HA formulations suitable for use in combination with PRP. Materials and Methods: HA/PRP blends have been obtained mixing human PRP and three different HA at different concentrations: 1) Sinovial, 0.8% (SN); 2) Sinovial Forte 1.6% (SF); 3) Sinovial HL 3.2% (HL); 4) Hyalubrix 1.5% (HX). Combinations of phosphate buffered saline (PBS) and the four HA types were used as control. Rheological measurements were performed on an Anton PaarMCR-302 rheometer. Amplitude sweep, frequency sweep and rotational measurements were performed and viscoelastic properties were evaluated. The rheological data were validated performing the tests in presence of Bovine Serum Albumin (BSA) up to ultra-physiological concentration (7%). Primary osteoarthritic chondrocytes were cultured in vitro with the HA and PRP blends in the culture medium for one week. Cell viability, proliferation and glycosaminoglycan (GAG) content were assessed. Results: PRP addition to HA leads to a decrease of viscoelastic shear moduli and increase of the crossover point, due to a pure dilution effect. For viscosupplements with HA concentration below 1% the viscoelasticity is mostly lost. Results were validated also in presence of proteins, which in synovial fluid are more abundant than HA. Chondrocytes proliferated overtime in all different culture conditions. The proliferation rate was higher in chondrocytes cultured in the media containing PRP compared to the cultures with different HA alone. GAG content was significantly higher in chondrocytes cultured in PRP and HL blend. Discussion: We investigated the rheological and biological properties of four different HA concentrations when combined with PRP giving insights on viscoelastic and biological properties of a promising approach for future OA therapy. Our data demonstrate that PRP addition is not detrimental to the viscosupplementation effect of HA. Viscosupplements containing low HA concentration are not indicated for combination with PRP, as the viscoelastic properties are lost. Although having the same rheological behavior of SF and HX, HL was superior in stimulating extracellular matrix production in vitro. [ABSTRACT FROM AUTHOR]

Published
2016
Full Text
View/download PDF

3. Frictional characterization of injectable hyaluronic acids is more predictive of clinical outcomes than traditional rheological or viscoelastic characterization

Author

Edward D. Bonnevie, Cynthia Secchieri, Devis Galesso, and Lawrence J. Bonassar

Subjects
Tribology, 02 engineering and technology, Physical Chemistry, chemistry.chemical_compound, Viscosity, 0302 clinical medicine, Skeletal Joints, Materials Physics, Lubrication, Hyaluronic acid, Medicine and Health Sciences, Clinical efficacy, Hyaluronic Acid, Musculoskeletal System, Multidisciplinary, Physics, 021001 nanoscience & nanotechnology, Chemistry, Treatment Outcome, Connective Tissue, Physical Sciences, Engineering and Technology, Medicine, Anatomy, Rheology, 0210 nano-technology, Research Article, Materials science, Friction, Drug Compounding, Science, Materials Science, Material Properties, Viscoelasticity, Injections, 03 medical and health sciences, Rheumatology, Humans, Mechanical Properties, 030203 arthritis & rheumatology, Rheometry, Arthritis, Mechanical Engineering, Biology and Life Sciences, Elasticity, Biological Tissue, Cartilage, Chemical Properties, chemistry, Arthritis therapy, Viscosupplementation, Biomedical engineering
Abstract

Hyaluronic acid injections have been a mainstay of arthritis treatment for decades. However, much controversy remains about their clinical efficacy and their potential mechanism of action. This approach to arthritis therapy is often called viscosupplementation, a term which is rooted in the elevated viscosity of the injected solutions. This terminology also suggests a mechanical pathway of action and further implies that their efficacy is dependent on viscosity. Notably, previous studies of the relationship between viscous properties of hyaluronic acid solutions and their clinical efficacy have not been definitive. Recently we developed an experimental and analytical framework for studying cartilage lubrication that captures the Stribeck-like behavior of cartilage in an elastoviscous transition curve. Here we apply this framework to study the lubricating behavior of six hyaluronan products currently used for injectable arthritis therapy in the US. Despite the fact that the source and chemical modifications endow these products with a range of lubricating properties, we show that the lubricating effect of all of these materials can be described by this Stribeck-like elastoviscous transition. Fitting this data to the elastoviscous transition model enables the calculation of effective lubricating viscosities for each material, which differ substantially from the viscosities measured using standard rheometry. Further we show that while data from standard rheometry are poor predictors of clinical performance of these materials, measurements of friction coefficient and effective lubricating viscosity correlate well (R2 = 0.77; p < 0.005) with assessments of improved clinical function reported previously. This approach offers both a novel method that can be used to evaluate potential clinical efficacy of hyaluronic acid formulations and provide new insight on their mode of action.

Published
2019

4. Viscoelastic parameters as discriminators of breast masses: Initial human study results

Author

Adriana Gregory, Max Denis, Azra Alizad, Mostafa Fatemi, Mohammad Mehrmohammadi, Viksit Kumar, Mahdi Bayat, and Robert T. Fazzio

Subjects
Biopsy, Velocity, lcsh:Medicine, Physical Chemistry, 01 natural sciences, 030218 nuclear medicine & medical imaging, Breast Diseases, 0302 clinical medicine, Nuclear magnetic resonance, Materials Physics, Medicine and Health Sciences, Breast, lcsh:Science, 010301 acoustics, Ultrasonography, Physics, Multidisciplinary, medicine.diagnostic_test, Viscosity, Ultrasound, Classical Mechanics, Soft tissue, Middle Aged, Chemistry, Kelvin–Voigt material, Physical Sciences, Elasticity Imaging Techniques, Female, Elastography, Anatomy, Research Article, Soft Tissues, Materials Science, Material Properties, Surgical and Invasive Medical Procedures, Breast Neoplasms, Human study, Vibration, Viscoelasticity, Diagnosis, Differential, Motion, 03 medical and health sciences, 0103 physical sciences, medicine, Mechanical Properties, Humans, Elasticity (economics), business.industry, lcsh:R, Reproductive System, Biology and Life Sciences, Acoustics, Elasticity, Biological Tissue, Chemical Properties, lcsh:Q, business, Breast Tissue
Abstract

Shear wave elastography is emerging as a clinically valuable diagnostic tool to differentiate between benign and malignant breast masses. Elastography techniques assume that soft tissue can be modelled as a purely elastic medium. However, this assumption is often violated as soft tissue exhibits viscoelastic properties. In order to explore the role of viscoelastic parameters in suspicious breast masses, a study was conducted on a group of patients using shear wave dispersion ultrasound vibrometry in the frequency range of 50-400 Hz. A total of 43 female patients with suspicious breast masses were recruited before their scheduled biopsy. Of those, 15 patients did not meet the data selection criteria. Voigt model based shear elasticity showed a significantly (p = 7.88x10(-6)) higher median value for the 13 malignant masses (16.76±13.10 kPa) compared to 15 benign masses (1.40±1.12 kPa). Voigt model based shear viscosity was significantly different (p = 4.13x10(-5)) between malignant (8.22±3.36 Pa-s) and benign masses (2.83±1.47 Pa-s). Moreover, the estimated time constant from the Voigt model, which is dependent on both shear elasticity and viscosity, differed significantly (p = 6.13x10(-5)) between malignant (0.68±0.33 ms) and benign masses (3.05±1.95 ms). Results suggest that besides elasticity, viscosity based parameters like shear viscosity and time constant can also be used to differentiate between malignant and benign breast masses.

Published
2018

Catalog

Books, media, physical & digital resources
See catalog results