Analysis of Proteoglycan Content and Biomechanical Properties in Arthritic and Arthritis-Free Menisci

Studies on osteoarthritis of the knee have examined isolated aspects of the meniscus biomechanically and histologically, but not the difference between instantaneous modulus (IM) in healthy and diseased samples. The aim of this study is to investigate the difference in the biomechanical behavior and proteoglycan content between arthritic and arthritis-free menisci. In addition, the relationship between the biomechanical behavior and proteoglycan content should be investigated. A novel indentation-based method was used, which allows the mapping of the entire meniscus, without damaging it for histological examinations. A total of 26 arthritic and 14 arthritis-free samples were examined in the present study. A Mach-1 Model V500css test machine was used for biomechanical testing. A position grid was placed over each sample allowing all measurements (indentation test and thickness measurements) to be taken at the same position. All sections were then graded for Safranin O staining intensity for proteoglycan content. The maximum applied load of our arthritic samples above the posterior horn was statistically significantly higher (p = 0.01) at 0.02 ± 0.02 N than the maximum applied load of the arthritis-free samples at 0.01 ± 0.01 N. The proteoglycan content of the meniscus, evaluated by the Safranin O score, correlated statistically significantly with the maximum applied load over the entire meniscus (p = 0.04, 95% CI: 0.06–0.71). The present study showed that in the final stage of gonarthritis, the attenuation behavior of the meniscus was significantly lower compared to the arthritis-free knee. The mapping of IM and histological examination of the meniscus showed a direct correlation between changes in proteoglycan content and altered mechanical properties of the meniscus in gonarthritis.

Download Full-text

Strength of side-to-side and step-cut repairs in tendon transfers: biomechanical testing of porcine flexor tendons

Journal of Hand Surgery (European Volume) ◽

10.1177/1753193420939068 ◽

2020 ◽

Vol 45 (10) ◽

pp. 1061-1065

Author(s):

Eivind Strandenes ◽

Peter Ellison ◽

Anders O. Mølster ◽

Nils R. Gjerdet ◽

Irene O. Moldestad ◽

...

Keyword(s):

Tensile Properties ◽

Testing Machine ◽

Biomechanical Testing ◽

Maximum Load ◽

Side Group ◽

Tendon Transfers ◽

Flexor Tendons ◽

Active Mobilization ◽

The Difference

The aim of the study was to compare side-to-side with step-cut repairs to determine how much of the width it is possible to remove and still keep the repair strong enough to start active mobilization. Porcine flexor tendons were used to create side-to-side, one-third step-cut and half step-cut repairs. There were 15 repairs in each group. The tensile properties of the constructs were measured in a biomechanical testing machine. All repairs failed by the sutures splitting the tendon longitudinally. The maximum load and stiffness were highest in the side-to-side group. Our findings suggest that the half step-cut repair can withstand the forces exerted during active unrestricted movement of the digits in tendons of this size. The advantage of the step-cut repair is reduced bulkiness and less friction, which might compensate for the difference in strength.

Download Full-text

DNA repair proteins may differentiate papillary thyroid cancer from chronic lymphocytic thyroiditis and nodular colloidal goiter

Scientific Reports ◽

10.1038/s41598-021-89403-0 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Bahri Evren ◽

Sami Yılmaz ◽

Neşe Karadağ ◽

Ayşe Çıkım Sertkaya ◽

Ömercan Topaloğlu ◽

...

Keyword(s):

Dna Repair ◽

Thyroid Cancer ◽

Papillary Carcinoma ◽

Staining Intensity ◽

Follicular Cell ◽

Papillary Thyroid ◽

Chronic Thyroiditis ◽

Dna Repair Proteins ◽

The Difference ◽

Repair Genes

AbstractMalignant thyroid lesions are the most common malignancy of the endocrine glands with increasing rates in the last two decades. Papillary thyroid cancer is the most common thyroid malignancy. In our study, we aimed to quantitatively evaluate the levels of DNA repair proteins MSH2, MLH1, MGMT, which are representative blocks of patients diagnosed with papillary carcinoma, chronic thyroiditis, or colloidal goiter. Total or subtotal thyroidectomy material of 90 patients diagnosed with papillary carcinoma, nodular colloidal goiter, or chronic thyroiditis between 2009 and 2012 were retrospectively evaluated. Tissue samples obtained from paraffin blocks were stained with MGMT, MSH2, MLH1 proteins and their immunohistochemistry was evaluated. Prepared sections were examined qualitatively by an impartial pathologist and a clinician, taking into account the staining method under the trinocular light microscope. Although there was no statistically significant difference in MGMT, MSH2, MLH1, follicular cell positivity, staining intensity, and immunoreactivity values, papillary carcinoma cases showed a higher rate of follicular cell positivity, and this difference was more pronounced between papillary carcinoma and colloidal goiter. In the MSH2 follicular cell positivity evaluation, the difference between chronic thyroiditis and colloidal goiter was significant (p = 0.023). The difference between chronic thyroiditis and colloidal goiter was significant in the MSH2 staining intensity evaluation (p = 0.001). The difference between chronic thyroiditis and colloidal goiter was significant in MLH1 immunoreactivity evaluation (p = 0.012). Papillary carcinoma cases were demonstrated by nuclear staining only for MSH2 and MLH1 proteins as opposed to hyperplastic nodules. The higher levels of expression of DNA repair genes in malignant tumors compared to benign tumors are attributed to the functional activation of DNA repair genes. Further studies are needed for DNA repair proteins to be a potential test in the development and progression of thyroid cancer.

Download Full-text

Influence of different concentrations of fibrinogen on the properties of a fibrin matrix for vascular tissue engineering

I P Pavlov Russian Medical Biological Herald ◽

10.23888/pavlovj202129121-34 ◽

2021 ◽

Vol 29 (1) ◽

pp. 21-34

Author(s):

Vera G. Matveeva ◽

Mariam Yu. Khanova ◽

Tatyana V. Glushkova ◽

Larisa V. Antonova

Keyword(s):

Mechanical Properties ◽

Tissue Engineering ◽

Metabolic Activity ◽

Vascular Tissue ◽

Physical And Mechanical Properties ◽

Vascular Tissue Engineering ◽

Test Machine ◽

Fibrin Matrix ◽

Before And After ◽

The Difference

Aim. To evaluate the potential utility of fibrin matrices containing 10, 20, and 25 mg/ml of fibrinogen (fibrin-10, fibrin-20, and fibrin-30, respectively) in vascular tissue engineering (VTE). Materials and Methods. Fibrinogen was isolated using the method of ethanol cryoprecipitation and polymerized using a solution of thrombin and CaCl2. The fibrin structure was studied in a scanning electron microscope, and the physical and mechanical properties of the material were tested on a Zwick/Roell test machine. The metabolic activity of endothelial cells (EC) on the fibrin surface was evaluated by the MTT assay, and the viability of fibroblasts in the thickness of fibrin and possibility for migration by in fluorescent and light microscopy. Percent of fibrin shrinkage was determined from the difference in the sample volumes before and after removal of moisture. Results. The fiber diameter did not differ among all fibrin samples, but the pore diameter in fibrin-30 was smaller than those in fibrin-10 and fibrin-20. A possibility for migration of fibroblasts into the depth of the fibrin matrix and preservation of 97-100% viability of cells at a depth 5 mm was confirmed. The metabolic activity of EC on the surface of fibrin-20 and fibrin-30 exceeded that on collagen, fibronectin, and fibrin-10. All fibrin samples shrank in volume to 95.5-99.5%, and the highest shrinkage was seen in fibrin-10. The physical and mechanical properties of fibrin were inferior to those of human A. mammaria by a factor of 10. Conclusion. Fibrin with fibrinogen concentrations of 20 and 30 mg/ml maintains a high metabolic and proliferative activity of EC on the surface and also a high viability of fibroblasts in the matrix. Its availability, ease of preparation, and a number of other favorable properties make fibrin a promising material for VTE. However, the problem of insufficient strength requires further investigations.

Download Full-text

Changes in Matrix Components in the Developing Human Meniscus

The American Journal of Sports Medicine ◽

10.1177/0363546520972418 ◽

2020 ◽

Vol 49 (1) ◽

pp. 207-214

Author(s):

William Fedje-Johnston ◽

Ferenc Tóth ◽

Melissa Albersheim ◽

Cathy S. Carlson ◽

Kevin G. Shea ◽

...

Keyword(s):

Blood Vessels ◽

Cell Density ◽

Skeletal Maturity ◽

Skeletal Development ◽

Collagen Type I ◽

Type I ◽

Cellular Density ◽

Meniscal Healing ◽

Proteoglycan Content ◽

Safranin O

Background: Treatment of meniscal tears is necessary to maintain the long-term health of the knee joint. Morphological elements, particularly vascularity, that play an important role in meniscal healing are known to change during skeletal development. Purpose: To quantitatively evaluate meniscal vascularity, cellularity, collagen, and proteoglycan content by age and location during skeletal development. Study Design: Descriptive laboratory study. Methods: Medial and lateral menisci from 14 male and 7 female cadavers aged 1 month to 11 years were collected and evaluated. For each meniscus, histologic and immunohistologic techniques were used to establish the ratio of the area of proteoglycan (safranin O) positivity to the total area (proteoglycan ratio), collagen type I and type II immunostaining positivity, number of blood vessels, and cell density. These features were evaluated over the entire meniscus and also separately in 5 circumferential segments: anterior root, anterior horn, body, posterior horn, and posterior root. Additionally, cell density and number of blood vessels were examined in 3 radial regions: inner, middle, and periphery. Results: Age was associated with a decrease in meniscal vessel count and cell density, while the proteoglycan ratio increased with skeletal maturity. Differences in vessel counts, cellular density, and proteoglycan ratio in different anatomic segments as well as in the inner, middle, and peripheral regions of the developing menisci were also observed. Collagen immunostaining results were inconsistent and not analyzed. Conclusion: The cellularity and vascularity of the developing meniscus decrease with age and the proteoglycan content increases with age. All of these parameters are influenced by location within the meniscus. Clinical Relevance: Age and location differences in meniscal morphology, particularly in the number of blood vessels, are expected to influence meniscal healing.

Download Full-text

Analysis of Mandibular Test Specimens Used to Assess a Bone Fixation System

Craniomaxillofacial Trauma & Reconstruction ◽

10.1055/s-0034-1393732 ◽

2015 ◽

Vol 8 (3) ◽

pp. 171-178 ◽

Cited By ~ 1

Author(s):

LeandroStocco Baccarin ◽

Renato Correa Viana Casarin ◽

JorgeVicente Lopes-da-Silva ◽

LuisAugusto Passeri

Keyword(s):

Biomechanical Testing ◽

Load Resistance ◽

Fixation Method ◽

Sagittal Split Ramus Osteotomy ◽

Biomechanical Behavior ◽

Synthetic Materials ◽

Group A ◽

Materials Used ◽

Group B

The aim of this study was to assess through biomechanical testing if different synthetic materials used to fabricate test specimens have a different biomechanical behavior in comparison with other materials when simulating in vitro load resistance of a fixation method established for sagittal split ramus osteotomy (SSRO). Thirty synthetic and standardized human hemimandible replicas with SSRO were divided into three groups of 10 samples each. Group A—ABS plastic; Group B—polyamide; and Group C—polyurethane. These were fixated with three bicortical position screws (16 mm in length, 2.0-mm system) in an inverted L pattern using perforation guide and 5-mm advancement. Each sample was submitted to linear vertical load, and load strength values were recorded at 1, 3, 5, 7, and 10 mm of displacement. The means and standard deviation were compared using the analysis of variance ( p < 0.05) and the Tukey test. A tendency for lower values was observed in Group B in comparison with Groups A and C. At 3 and 5 mm of displacement, a difference between Groups A and C was found in comparison with Group B ( p < 0.05). At 7 and 10 mm of displacement, a difference was found among the three groups, in which Group C showed the highest values and Group B the lowest ( p < 0.05). Taking into consideration the results obtained and the behavior of each material used as a substrate, significant differences occurred among the materials when compared among them.

Download Full-text

Investigation of the Cracking Behaviors by Indentation Based on an In Situ Observation

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.627.361 ◽

2014 ◽

Vol 627 ◽

pp. 361-364 ◽

Cited By ~ 1

Author(s):

Yasuhiro Yamazaki

Keyword(s):

Indentation Test ◽

Crack Size ◽

Indentation Load ◽

In Situ Measurement ◽

Observation System ◽

In Situ Observation ◽

Test Machine ◽

Transparent Ceramics ◽

The Relationship

In this paper, an in-situ measurement of crack size as a function of applied indentation load during indentation test was conducted. To perform the in-situ measurement, an instrumented indentation test machine with the in-situ observation system was developed and used. The joints of transparent ceramics by diffusion bonding were prepared as the specimen used in this study. The indentations were performed at the interface of the joints, and in the monolithic transparent ceramics by means of the instrumented indenter with the in-situ observation system. The relationship between crack shape and indentation load, as well as, the effect of the indenter shape on it were discussed.

Download Full-text

Biomechanical Behavior of the Temporomandibular Joint Disc

Critical Reviews in Oral Biology & Medicine ◽

10.1177/154411130301400207 ◽

2003 ◽

Vol 14 (2) ◽

pp. 138-150 ◽

Cited By ~ 138

Author(s):

Eiji Tanaka ◽

Theo van Eijden

Keyword(s):

Temporomandibular Joint ◽

Viscoelastic Behavior ◽

Collagen Fibers ◽

Extrinsic Factors ◽

Temporomandibular Joint Disc ◽

Applied Loading ◽

Biomechanical Behavior ◽

Flow Through ◽

The Difference ◽

Fiber Mesh

The temporomandibular joint (TMJ) disc consists mainly of collagen fibers and proteoglycans constrained in the interstices of the collagen fiber mesh. This construction results in a viscoelastic response of the disc to loading and enables the disc to play an important role as a stress absorber during function. The viscoelastic properties depend on the direction (tension, compression, and shear) and the type of the applied loading (static and dynamic). The compressive elastic modulus of the disc is smaller than its tensile one because the elasticity of the disc is more dependent on the collagen fibers than on the proteoglycans. When dynamic loading occurs, the disc is likely to behave less stiffly than under static loading because of the difference of fluid flow through and out of the disc during loading. In addition, the mechanical properties change as a result of various intrinsic and extrinsic factors in life such as aging, trauma, and pathology. Information about the viscoelastic behavior of the disc is required for its function to be understood and, for instance, for a suitable TMJ replacement device to be constructed. In this review, the biomechanical behavior of the disc in response to different loading conditions is discussed.

Download Full-text

Experimental Study of Thermal Effects in Tilting-Pad Journal Bearings at High Operating Speeds

Journal of Tribology ◽

10.1115/1.2831570 ◽

1996 ◽

Vol 118 (3) ◽

pp. 532-538 ◽

Cited By ~ 10

Author(s):

C. Bouchoule ◽

M. Fillon ◽

D. Nicolas ◽

F. Barresi

Keyword(s):

Thermal Effects ◽

Applied Load ◽

Journal Bearings ◽

Test Machine ◽

Power Losses ◽

Test Bed ◽

Tilting Pad ◽

Oil Flow ◽

Bearing Design ◽

Tilting Pad Journal Bearings

In this work, a test machine, experimental results and the comparison between theoretical TEHD results and experimental data are presented. The tested bearings are located in two speed increasing and reduction gearboxes (back-to-back test bed). The shaft is driven by a 1 MW motor. The bearing diameter and the bearing length are equal to 160 mm. The rotational speed varies from 2700 rpm (22 m/s) to 11,880 rpm (100 m/s). The applied load is up to 88,000 N. Temperatures in the bearing (film/pad interface, oil, pad and housing), power losses and oil flow are measured. The influence of the bearing design and of the pivot position on the pad is analyzed.

Download Full-text

Nondestructive Assessment of Articular Cartilage Electromechanical Properties after Osteochondral Autologous and Allogeneic Transplantation in a Goat Model

Cartilage ◽

10.1177/1947603518786543 ◽

2018 ◽

Vol 11 (3) ◽

pp. 348-357

Author(s):

Tomas Mickevicius ◽

Alius Pockevicius ◽

Audrius Kucinskas ◽

Rimtautas Gudas ◽

Justinas Maciulaitis ◽

...

Keyword(s):

Articular Cartilage ◽

Platelet Rich Plasma ◽

Allogeneic Transplantation ◽

Staining Intensity ◽

Quality Parameters ◽

Electromechanical Properties ◽

Diagnostic Device ◽

Safranin O ◽

Femoral Condyles

Objective To determine the applicability of a minimally invasive diagnostic device to evaluate the quality of articular cartilage following autologous (OAT) and allogeneic (OCA) osteochondral graft transplantation in goat model. Design OAT grafts were harvested from lateral femoral condyles (LFCs) and transplanted into osteochondral defects created in medial femoral condyles (MFCs) of contralateral knees. OCA grafts were transplanted into MFC condyles after in vitro storage. Autologous platelet-rich plasma (PRP) was administered intraarticularly after the surgery and at 1 and 2 months postoperatively. OAT and OCA grafts were evaluated macroscopically (Oswestry arthroscopy score [OAS]), electromechanically (quantitative parameter, QP), and histologically (O’Driscoll score, safranin O staining intensity) at 3 and 6 months after transplantation. Results were compared with preoperative graft evaluation. Results Transplanted cartilage deteriorated within 6 months in all groups. Cartilage quality was better retained in OAT group compared with a decline in OCA group. QP and OAS scores were comparable in OAT and OCA groups at 3 months, but superior in OAT group at 6 months, according to all the methods applied. PRP injections significantly improved QP and OAS score at 6 months compared with 3 months in OAT group. QP moderately correlated with OAS, O’Driscoll score, and safranin O staining intensity. Conclusions Grafts did not retain preoperative quality parameters at 6 months follow-up; however, OAT were superior to OCA grafts. PRP may have a beneficial effect on macroscopic and electromechanical properties of cartilage; however, histological improvement is yet to be proved. Electromechanical diagnostic device enables reliable assessment of transplanted cartilage.

Download Full-text

Use of Indentation Test to Determine the Proteoglycan Content of Articular Cartilage

Advances in Bioengineering ◽

10.1115/imece2002-32619 ◽

2002 ◽

Author(s):

Xin Lu ◽

Daniel D. Sun ◽

X. Edward Guo ◽

Hui Chen ◽

W. Michael Lai ◽

...

Keyword(s):

Mechanical Properties ◽

Articular Cartilage ◽

Indentation Test ◽

Solid Matrix ◽

Interstitial Fluid Flow ◽

Fibrous Network ◽

Indentation Experiment ◽

Proteoglycan Content ◽

Creep And Stress Relaxation ◽

First Time

The indentation experiment has been widely used to determine mechanical properties of articular cartilage [e.g., 1–3]. This method does not disrupt the fibrous network of the tissue nor does it require removing the tissue from the underlying bone. The biphasic indentation theory has been successfully used to determine the effect of interstitial fluid flow and pressurization (load support) on the creep and stress-relaxation behaviors of articular cartilage, and to determine its apparent mechanical properties (i.e., the elastic moduli of the extracellular solid matrix and its permeability) [1, 3]. However, due to its proteoglycan content, articular cartilage is a charged tissue with a high fixed charge density (FCD) [4]. Proteoglycan and collagen contents, water, etc, vary with age or with orthteoarthritis [4, 5]. The FCD plays important physicochemical roles in load support and mechano-electrochemial behaviors of the tissue and also regulates chondrocyte biosynthetic activities [4–7]. It is therefore important to develop an effective technique to determine not only the mechanical properties but also the electrochemical property (e.g., FCD) of the tissue, simultaneously and at the same location. The purpose of the current study is to determine, for the first time, both the mechanical properties and FCD of the extracellular matrix using an indentation test.

Download Full-text