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Sample records for alters cartilage turnover

  1. The turnover of mineralized growth plate cartilage into bone may be regulated by osteocytes.

    Science.gov (United States)

    Cox, Lieke G E; van Rietbergen, B; van Donkelaar, C C; Ito, K

    2011-06-01

    During endochondral ossification, growth plate cartilage is replaced with bone. Mineralized cartilage matrix is resorbed by osteoclasts, and new bone tissue is formed by osteoblasts. As mineralized cartilage does not contain any cells, it is unclear how this process is regulated. We hypothesize that, in analogy with bone remodeling, osteoclast and osteoblast activity are regulated by osteocytes, in response to mechanical loading. Since the cartilage does not contain osteocytes, this means that cartilage turnover during endochondral ossification would be regulated by the adjacent bone tissue. We investigated this hypothesis with an established computational bone adaptation model. In this model, osteocytes stimulate osteoblastic bone formation in response to the mechanical bone tissue loading. Osteoclasts resorb bone near randomly occurring microcracks that are assumed to block osteocyte signals. We used finite element modeling to evaluate our hypothesis in a 2D-domain representing part of the growth plate and adjacent bone. Cartilage was added at a constant physiological rate to simulate growth. Simulations showed that osteocyte signals from neighboring bone were sufficient for successful cartilage turnover, since equilibrium between cartilage remodeling and growth was obtained. Furthermore, there was good agreement between simulated bone structures and rat tibia histology, and the development of the trabecular architecture resembled that of infant long bones. Additionally, prohibiting osteoclast invasion resulted in thickened mineralized cartilage, similar to observations in a knock-out mouse model. We therefore conclude that it is well possible that osteocytes regulate the turnover of mineralized growth plate cartilage. PMID:21546025

  2. A Novel Approach to Stimulate Cartilage Repair: Targeting Collagen Turnover

    NARCIS (Netherlands)

    Y.M. Bastiaansen-Jenniskens (Yvonne Maria)

    2009-01-01

    textabstractOA is a complex disease of which the ethiopathology is not completely known and therapies to repair cartilage are still under investigation. The increase of collagen type II expression in osteoarthritic cartilage suggests an activated repair mechanism that is however ineffective in repai

  3. A Novel Approach to Stimulate Cartilage Repair: Targeting Collagen Turnover

    OpenAIRE

    Bastiaansen-Jenniskens, Yvonne Maria

    2009-01-01

    textabstractOA is a complex disease of which the ethiopathology is not completely known and therapies to repair cartilage are still under investigation. The increase of collagen type II expression in osteoarthritic cartilage suggests an activated repair mechanism that is however ineffective in repairing or maintaining the ECM homeostasis. We therefore investigated the ability to modulate the formation of a functional collagen type II network that can ultimately contribute to innovation of car...

  4. Cartilage turnover reflected by metabolic processing of type II collagen

    DEFF Research Database (Denmark)

    Gudmann, Karoline Natasja Stæhr; Wang, Jianxia; Hoielt, Sabine;

    2014-01-01

    The aim of this study was to enable measurement of cartilage formation by a novel biomarker of type II collagen formation. The competitive enzyme-linked immunosorbent assay (ELISA) Pro-C2 was developed and characterized for assessment of the beta splice variant of type II procollagen (PIIBNP). This...... our models. To our knowledge this is the first assay, which is able to specifically evaluate PIIBNP excretion. The Pro-C2 assay seems to provide a promising and novel marker of type II collagen formation....

  5. Goserelin, as an ovarian protector during (neoadjuvant breast cancer chemotherapy, prevents long term altered bone turnover

    Directory of Open Access Journals (Sweden)

    Caroline Wilson

    2016-03-01

    Conclusion: Addition of G to CT increases bone turnover during treatment with normalisation after cessation of treatment suggesting G may offer sufficient ovarian protection against CT induced POI to negate longstanding altered bone turnover associated with POI.

  6. Alterations in periarticular bone and cross talk between subchondral bone and articular cartilage in osteoarthritis

    OpenAIRE

    Goldring, Steven R.

    2012-01-01

    The articular cartilage and the subchondral bone form a biocomposite that is uniquely adapted to the transfer of loads across the diarthrodial joint. During the evolution of the osteoarthritic process biomechanical and biological processes result in alterations in the composition, structure and functional properties of these tissues. Given the intimate contact between the cartilage and bone, alterations of either tissue will modulate the properties and function of the other joint component. T...

  7. Alterations in periarticular bone and cross talk between subchondral bone and articular cartilage in osteoarthritis.

    Science.gov (United States)

    Goldring, Steven R

    2012-08-01

    The articular cartilage and the subchondral bone form a biocomposite that is uniquely adapted to the transfer of loads across the diarthrodial joint. During the evolution of the osteoarthritic process biomechanical and biological processes result in alterations in the composition, structure and functional properties of these tissues. Given the intimate contact between the cartilage and bone, alterations of either tissue will modulate the properties and function of the other joint component. The changes in periarticular bone tend to occur very early in the development of OA. Although chondrocytes also have the capacity to modulate their functional state in response to loading, the capacity of these cells to repair and modify their surrounding extracellular matrix is relatively limited in comparison to the adjacent subchondral bone. This differential adaptive capacity likely underlies the more rapid appearance of detectable skeletal changes in OA in comparison to the articular cartilage. The OA changes in periarticular bone include increases in subchondral cortical bone thickness, gradual decreases in subchondral trabeular bone mass, formation of marginal joint osteophytes, development of bone cysts and advancement of the zone of calcified cartilage between the articular cartilage and subchondral bone. The expansion of the zone of calcified cartilage contributes to overall thinning of the articular cartilage. The mechanisms involved in this process include the release of soluble mediators from chondrocytes in the deep zones of the articular cartilage and/or the influences of microcracks that have initiated focal remodeling in the calcified cartilage and subchondral bone in an attempt to repair the microdamage. There is the need for further studies to define the pathophysiological mechanisms involved in the interaction between subchondral bone and articular cartilage and for applying this information to the development of therapeutic interventions to improve the

  8. ASDAS, BASDAI and different treatment responses and their relation to biomarkers of inflammation, cartilage and bone turnover in patients with axial spondyloarthritis treated with TNF{alpha} inhibitors

    DEFF Research Database (Denmark)

    Pedersen, Susanne Juhl; Sørensen, Inge Juul; Garnero, Patrick;

    2011-01-01

    To investigate the relation between ankylosing spondylitis disease activity score (ASDAS), Bath ankylosing spondylitis disease activity index (BASDAI) and treatment response and biomarkers of inflammation (C-reactive protein (CRP), interleukin-6 (IL-6), YKL-40), angiogenesis (vascular endothelial...... growth factor (VEGF)), cartilage (C-terminal crosslinking telopeptide of type II collagen (CTX-II), matrix metalloproteinase-3 (MMP-3), total aggrecan, cartilage oligomeric matrix protein) and bone (C-terminal crosslinking telopeptide of type I collagen, osteocalcin) turnover in 60 patients with axial...

  9. ASDAS, BASDAI and different treatment responses and their relation to biomarkers of inflammation, cartilage and bone turnover in patients with axial spondyloarthritis treated with TNFα inhibitors

    DEFF Research Database (Denmark)

    Pedersen, Susanne Juhl; Sørensen, Inge Juul; Garnero, Patrick;

    2011-01-01

    To investigate the relation between ankylosing spondylitis disease activity score (ASDAS), Bath ankylosing spondylitis disease activity index (BASDAI) and treatment response and biomarkers of inflammation (C-reactive protein (CRP), interleukin-6 (IL-6), YKL-40), angiogenesis (vascular endothelial...... growth factor (VEGF)), cartilage (C-terminal crosslinking telopeptide of type II collagen (CTX-II), matrix metalloproteinase-3 (MMP-3), total aggrecan, cartilage oligomeric matrix protein) and bone (C-terminal crosslinking telopeptide of type I collagen, osteocalcin) turnover in 60 patients with axial...

  10. The response to estrogen deprivation on cartilage collagen degradation markers; CTX-II is unique compared to other markers of collagen turnover

    DEFF Research Database (Denmark)

    Bay-Jensen, Anne-Christine; Tabassi, Nadine; Sondergaard, Lene;

    2009-01-01

    ABSTRACT: INTRODUCTION: The urinary level of type II collagen degradation marker CTX-II is increased in postmenopausal women and in ovariectomized rats, suggesting that estrogen deprivation induces cartilage breakdown. Here we investigate whether this response to estrogen holds true for other type...... II collagen turnover markers known to be affected in osteoarthritis, and whether it relates to its presence in specific areas of cartilage tissue. METHODS: The type II collagen degradation markers CTX-II and Helix-II were measured in body fluids of pre- and postmenopausal women and of ovariectomized...... rats receiving estrogen or not. Levels of PIIANP, a marker of type II collagen synthesis, were also measured in rats. Rat knee cartilage was analyzed for immunoreactivity of CTX-II and PIIANP and for type II collagen expression. RESULTS: As expected, urinary levels of CTX-II are significantly increased...

  11. The collagen turnover profile is altered in patients with inguinal and incisional hernia

    DEFF Research Database (Denmark)

    Henriksen, Nadia A; Mortensen, Joachim H; Sorensen, Lars T;

    2015-01-01

    the interstitial matrix (types I, III, and V collagens) and in the basement membrane (type IV collagen). MATERIAL AND METHODS: Patients with 3 different types of hernias were included: Primary unilateral inguinal hernia (n = 17), multiple hernias defined as ≥3 hernias (n = 21), and incisional hernia...... degradation (C1M, C3M, C5M, and C4M) were measured in serum by validated, solid-phase competitive assays. RESULTS: In inguinal hernia patients, the turnover of the interstitial matrix collagens type III (P < .042) and V (P < .001) was decreased compared with controls, whereas the turnover of the basement...... membrane collagen type IV was increased (P < .001). In incisional hernia patients, the turnover of type V collagen was decreased (P = .048) and the turnover of type IV collagen was increased compared with the hernia-free controls (P < .001). CONCLUSION: Hernia patients demonstrated systemically altered...

  12. Altered swelling and ion fluxes in articular cartilage as a biomarker in osteoarthritis and joint immobilization: a computational analysis

    OpenAIRE

    Manzano, Sara; Manzano, Raquel; Doblaré, Manuel; Doweidar, Mohamed Hamdy

    2015-01-01

    In healthy cartilage, mechano-electrochemical phenomena act together to maintain tissue homeostasis. Osteoarthritis (OA) and degenerative diseases disrupt this biological equilibrium by causing structural deterioration and subsequent dysfunction of the tissue. Swelling and ion flux alteration as well as abnormal ion distribution are proposed as primary indicators of tissue degradation. In this paper, we present an extension of a previous three-dimensional computational model of the cartilage ...

  13. Dysplastic histogenesis of cartilage growth plate by alteration of sulphation pathway: a transgenic model.

    Science.gov (United States)

    Cornaglia, Antonia Icaro; Casasco, Andrea; Casasco, Marco; Riva, Federica; Necchi, Vittorio

    2009-01-01

    Mutations in the diastrophic dysplasia sulphate transporter (dtdst) gene causes different forms of chondrodysplasia in the human. The generation of a knock-in mouse strain with a mutation in dtdst gene provides the basis to study developmental dynamics in the epiphyseal growth plate and long bone growth after impairment of the sulphate pathway. Our microscopical and histochemical data demonstrate that dtdst gene impairment deeply affects tissue organization, matrix structure, and cell differentiation in the epiphyseal growth plate. In mutant animals, the height of the growth plate was significantly reduced, according to a concomitant decrease in cell density and proliferation. Although the pathway of chondrocyte differentiation seemed complete, alteration in cell morphology compared to normal counterparts was detected. In the extracellular matrix, it we observed a dramatic decrease in sulphated proteoglycans, alterations in the organization of type II and type X collagen fibers, and premature onset of mineralization. These data confirm the crucial role of sulphate pathway in proteoglycan biochemistry and suggest that a disarrangement of the extracellular matrix may be responsible for the development of dtdts cartilage dysplasia. Moreover, we corroborated the concept that proteoglycans not only are structural components of the cartilage architecture, but also play a dynamic role in the regulation of chondrocyte growth and differentiation. PMID:19637059

  14. Effect of Age-Related Cartilage Turnover on Serum C-Telopeptide of Collagen Type II and Osteocalcin Levels in Growing Rabbits with and without Surgically Induced Osteoarthritis

    Directory of Open Access Journals (Sweden)

    Chung-Cheng Huang

    2014-01-01

    Full Text Available This study aims to determine the effect of age-related cartilage turnover on the serum C-telopeptide of type II collagen (CTX-II and osteocalcin (OC levels in growing rabbits with and without surgically induced osteoarthritis. Twenty-four New Zealand male 3-month-old rabbits were randomized into three operated groups (n = 6 per group, with surgically induced osteroarthritis in the right knee; after blood sampling, the knees were harvested following euthanization at 2, 3, and 6 months after surgery and a control group (n = 6, blood samples were obtained monthly between 3 and 15 months. Histomorphologically, the medial femoral condyles, particularly the central parts, harbored the most severe osteoarthritic changes among the operated rabbits. The serum levels of CTX-II and OC decreased in the controls from 3 to 11 months and then remained stable. No significant differences in the serum CTX-II and OC levels between the osteoarthritic rabbits and controls were observed. The osteoarthritic-to-normal ratios (ONRs, the ratios of serum CTX-II or OC levels in osteoarthritic rabbits to those of the controls at same ages enabled an overall assessment of osteoarthritis and age-related cartilage turnover. Elevated CTX-II ONRs were observed in rabbits with mild to advanced osteoarthritis. However, the OC ONRs were unhelpful in assessing osteoarthritic growing rabbits.

  15. Transplantation of sheep embrionic stem cells in cartilage lesions: preliminary observations

    OpenAIRE

    Rocca, Stefano; Antuofermo, Elisabetta; Dattena, Maria; Manunta, Maria Lucia Gabriella M.; Pilichi, Susanna; Meloni, Floriana; Leoni, Antonio

    2007-01-01

    Once damaged, joint cartilage never completely regenerates. This is due to absence of vascularisation, slow cellular turnover and impossibility for inflammation mediators to reach the cartilage lesion. Even small lesions involve alteration in joint functionality and can cause invalidating pathologies. Treatment is complex and the surgical techniques used to repair the joint surfaces do not give satisfactory and durable results because the new tissue produced is fibrous cartilage. The...

  16. Glucosamine but not iboprofen alters cartilage turnover in osteoarthritis patients in response to physical training

    DEFF Research Database (Denmark)

    Petersen, S.G.; Saxne, T; Heinegard, D;

    2010-01-01

    treatment with glucosamine, ibuprofen or placebo. DESIGN: A 12-week double blind, placebo controlled, randomized study. METHOD: Thirty-six elderly patients with bilateral tibiofemoral knee OA determined by radiography were randomly assigned to treatment with glucosamine (n=12), ibuprofen (n=12) or placebo...... significant compared to both placebo and ibuprofen; the mean reduction with glucosamine was 13% vs placebo (P=0.0378) and 17% vs ibuprofen (P=0.0122). Urinary CTX-II levels did not change significantly in any of the three experimental groups. CONCLUSION: Serum COMP decreased significantly over the 12-week...

  17. Altered swelling and ion fluxes in articular cartilage as a biomarker in osteoarthritis and joint immobilization: a computational analysis

    Science.gov (United States)

    Manzano, Sara; Manzano, Raquel; Doblaré, Manuel; Doweidar, Mohamed Hamdy

    2015-01-01

    In healthy cartilage, mechano-electrochemical phenomena act together to maintain tissue homeostasis. Osteoarthritis (OA) and degenerative diseases disrupt this biological equilibrium by causing structural deterioration and subsequent dysfunction of the tissue. Swelling and ion flux alteration as well as abnormal ion distribution are proposed as primary indicators of tissue degradation. In this paper, we present an extension of a previous three-dimensional computational model of the cartilage behaviour developed by the authors to simulate the contribution of the main tissue components in its behaviour. The model considers the mechano-electrochemical events as concurrent phenomena in a three-dimensional environment. This model has been extended here to include the effect of repulsion of negative charges attached to proteoglycans. Moreover, we have studied the fluctuation of these charges owning to proteoglycan variations in healthy and pathological articular cartilage. In this sense, standard patterns of healthy and degraded tissue behaviour can be obtained which could be a helpful diagnostic tool. By introducing measured properties of unhealthy cartilage into the computational model, the severity of tissue degeneration can be predicted avoiding complex tissue extraction and subsequent in vitro analysis. In this work, the model has been applied to monitor and analyse cartilage behaviour at different stages of OA and in both short (four, six and eight weeks) and long-term (11 weeks) fully immobilized joints. Simulation results showed marked differences in the corresponding swelling phenomena, in outgoing cation fluxes and in cation distributions. Furthermore, long-term immobilized patients display similar swelling as well as fluxes and distribution of cations to patients in the early stages of OA, thus, preventive treatments are highly recommended to avoid tissue deterioration. PMID:25392400

  18. Stanozolol Decreases Bone Turnover Markers, Increases Mineralization, and Alters Femoral Geometry in Male Rats.

    Science.gov (United States)

    Nebot, E; Aparicio, V A; Camiletti-Moirón, D; Martinez, R; Erben, R G; Kapravelou, G; Sánchez-González, C; De Teresa, C; Porres, J M; López-Jurado, M; Aranda, P; Pietschmann, P

    2016-06-01

    Stanozonol (ST) is a synthetic derivative of testosterone; it has anabolic/androgenic activity, increasing both the turnover of trabecular bone and the endocortical apposition of bone. The present study aimed to examine the effects of ST on bone status in rats by bone mineral content, markers of formation and resorption, bone density, and structural and microarchitectural parameters. Twenty male Wistar rats were randomly distributed into two experimental groups corresponding to placebo or ST administration, which consisted of weekly intramuscular injections of 10 mg/kg body weight of ST. Plasma parameters were analyzed by immunoassay. Bone mineral content was determined by spectrophotometry. Bone mineral density (BMD) and structural parameters were measured by peripheral quantitative computed tomography, and trabecular and cortical microarchitecture by micro-computed tomography. Plasma Ca, Mg, and alkaline phosphatase were higher, and urinary Ca excretion, corticosterone, and testosterone concentrations lower in the ST group. Femur Ca content was higher and P content was lower in the ST, whereas osteocalcin, aminoterminal propeptides of type I procollagen, and C-terminal telopeptides of type I collagen were lower. Total cross-sectional, trabecular, and cortical/subcortical areas were lower in the ST. No differences were observed on BMD and area parameters of the diaphysis as well as on trabecular and cortical microarchitecture. The use of ST increases bone mineralization, ash percentage, and Ca and Mg content in femur. In spite of an absence of changes in BMD, geometric metaphyseal changes were observed. We conclude that ST alters bone geometry, leads to low bone turnover, and thus may impair bone quality. PMID:26801156

  19. Persistent Biomechanical Alterations After ACL Reconstruction Are Associated With Early Cartilage Matrix Changes Detected by Quantitative MR

    Science.gov (United States)

    Amano, Keiko; Pedoia, Valentina; Su, Favian; Souza, Richard B.; Li, Xiaojuan; Ma, C. Benjamin

    2016-01-01

    Background: The effectiveness of anterior cruciate ligament (ACL) reconstruction in preventing early osteoarthritis is debated. Restoring the original biomechanics may potentially prevent degeneration, but apparent pathomechanisms have yet to be described. Newer quantitative magnetic resonance (qMR) imaging techniques, specifically T1ρ and T2, offer novel, noninvasive methods of visualizing and quantifying early cartilage degeneration. Purpose: To determine the tibiofemoral biomechanical alterations before and after ACL reconstruction using magnetic resonance imaging (MRI) and to evaluate the association between biomechanics and cartilage degeneration using T1ρ and T2. Study Design: Cohort study; Level of evidence, 2. Methods: Knee MRIs of 51 individuals (mean age, 29.5 ± 8.4 years) with unilateral ACL injuries were obtained prior to surgery; 19 control subjects (mean age, 30.7 ± 5.3 years) were also scanned. Follow-up MRIs were obtained at 6 months and 1 year. Tibial position (TP), internal tibial rotation (ITR), and T1ρ and T2 were calculated using an in-house Matlab program. Student t tests, repeated measures, and regression models were used to compare differences between injured and uninjured sides, observe longitudinal changes, and evaluate correlations between TP, ITR, and T1ρ and T2. Results: TP was significantly more anterior on the injured side at all time points (P < .001). ITR was significantly increased on the injured side prior to surgery (P = .033). At 1 year, a more anterior TP was associated with elevated T1ρ (P = .002) and T2 (P = .026) in the posterolateral tibia and with decreased T2 in the central lateral femur (P = .048); ITR was associated with increased T1ρ in the posteromedial femur (P = .009). ITR at 6 months was associated with increased T1ρ at 1 year in the posteromedial tibia (P = .029). Conclusion: Persistent biomechanical alterations after ACL reconstruction are related to significant changes in cartilage T1ρ and T2 at 1 year

  20. Studies on the possible role of thyroid hormone in altered muscle protein turnover during sepsis

    International Nuclear Information System (INIS)

    Five days after thyroidectomy (Tx) or sham-Tx in young male Sprague-Dawley rats, sepsis was induced by cecal ligation and puncture (CLP). Control animals underwent laparotomy and manipulation of the cecum without ligation or puncture. Sixteen hours after CLP or laparotomy, protein synthesis and degradation were measured in incubated extensor digitorum longus (EDL) and soleus (SOL) muscles by determining rate of 14C-phenylalanine incorporation into protein and tyrosine release into incubation medium, respectively. Triiodothyronine (T3) was measured in serum and muscle tissue. Protein synthesis was reduced by 39% and 22% in EDL and SOL, respectively, 16 hours after CLP in sham-Tx rats. The response to sepsis of protein synthesis was abolished in Tx rats. Protein breakdown was increased by 113% and 68% in EDL and SOL, respectively, 16 hours after CLP in sham-Tx animals. The increase in muscle proteolysis during sepsis was blunted in hypothyroid animals and was 42% and 49% in EDL and SOL, respectively. T3 in serum was reduced by sepsis, both in Tx and sham-Tx rats. T3 in muscle, however, was maintained or increased during sepsis. Abolished or blunted response of muscle protein turnover after CLP in hypothyroid animals may reflect a role of thyroid hormones in altered muscle protein metabolism during sepsis. Reduced serum levels of T3, but maintained or increased muscle concentrations of the hormone, suggests that increased T3 uptake by muscle may be one mechanism of low T3 syndrome in sepsis, further supporting the concept of a role for thyroid hormone in metabolic alterations in muscle during sepsis

  1. Macrophage phagocytosis alters the MRI signal of ferumoxytol-labeled mesenchymal stromal cells in cartilage defects

    Science.gov (United States)

    Nejadnik, Hossein; Lenkov, Olga; Gassert, Florian; Fretwell, Deborah; Lam, Isaac; Daldrup-Link, Heike E.

    2016-05-01

    Human mesenchymal stem cells (hMSCs) are a promising tool for cartilage regeneration in arthritic joints. hMSC labeling with iron oxide nanoparticles enables non-invasive in vivo monitoring of transplanted cells in cartilage defects with MR imaging. Since graft failure leads to macrophage phagocytosis of apoptotic cells, we evaluated in vitro and in vivo whether nanoparticle-labeled hMSCs show distinct MR signal characteristics before and after phagocytosis by macrophages. We found that apoptotic nanoparticle-labeled hMSCs were phagocytosed by macrophages while viable nanoparticle-labeled hMSCs were not. Serial MRI scans of hMSC transplants in arthritic joints of recipient rats showed that the iron signal of apoptotic, nanoparticle-labeled hMSCs engulfed by macrophages disappeared faster compared to viable hMSCs. This corresponded to poor cartilage repair outcomes of the apoptotic hMSC transplants. Therefore, rapid decline of iron MRI signal at the transplant site can indicate cell death and predict incomplete defect repair weeks later. Currently, hMSC graft failure can be only diagnosed by lack of cartilage defect repair several months after cell transplantation. The described imaging signs can diagnose hMSC transplant failure more readily, which could enable timely re-interventions and avoid unnecessary follow up studies of lost transplants.

  2. Altered turnover and synthesis rates of lung surfactant following thoracic irradiation

    International Nuclear Information System (INIS)

    Between 2-6 weeks after thoracic irradiation with 10 Gy X rays, when levels of surfactant in the alveoli show the greatest increase, there is a reduction in the rate of radioactivity loss from 3H-choline labeled disaturated phosphatidylcholine from the lung. This indicates a reduced turnover of surfactant. Discrepancies between the halving times for specific activity and for total radioactivity of the disaturated phospholipids suggest that at between 2 and 3 weeks post-irradiation, removal and degradation of surfactant almost ceases, but that synthesis continues normally. However, by 3 weeks post-irradiation, choline-3H incorporation into disaturated phosphatidylcholine suggests that surfactant synthesis is increased about two-fold. The reduced number of macrophages recovered from alveolar lavage between about 2 and 6 weeks post-irradiation may indicate a reason for the lengthened turnover times of surfactant over this period. Nevertheless, the stimulated surfactant production that takes place from about 3 weeks onward suggests an additional active response to radiation or to radiation damage by the type II pneumonocytes. These studies confirm that the maximum levels of alveolar surfactant seen at 3 weeks post-irradiation result from a different lung response than that responsible for the increase in surfactant, which occurs within hours of irradiation

  3. Long-term soil transplant simulating climate change with latitude significantly alters microbial temporal turnover.

    Science.gov (United States)

    Liang, Yuting; Jiang, Yuji; Wang, Feng; Wen, Chongqing; Deng, Ye; Xue, Kai; Qin, Yujia; Yang, Yunfeng; Wu, Liyou; Zhou, Jizhong; Sun, Bo

    2015-12-01

    To understand soil microbial community stability and temporal turnover in response to climate change, a long-term soil transplant experiment was conducted in three agricultural experiment stations over large transects from a warm temperate zone (Fengqiu station in central China) to a subtropical zone (Yingtan station in southern China) and a cold temperate zone (Hailun station in northern China). Annual soil samples were collected from these three stations from 2005 to 2011, and microbial communities were analyzed by sequencing microbial 16S ribosomal RNA gene amplicons using Illumina MiSeq technology. Our results revealed a distinctly differential pattern of microbial communities in both northward and southward transplantations, along with an increase in microbial richness with climate cooling and a corresponding decrease with climate warming. The microbial succession rate was estimated by the slope (w value) of linear regression of a log-transformed microbial community similarity with time (time-decay relationship). Compared with the low turnover rate of microbial communities in situ (w=0.046, Pbiodiversity. PMID:25989371

  4. The response to oestrogen deprivation of the cartilage collagen degradation marker, CTX-II, is unique compared with other markers of collagen turnover

    DEFF Research Database (Denmark)

    Bay-Jensen, Anne-Christine; Tabassi, Nadine C B; Sondergaard, Lene V;

    2009-01-01

    The urinary level of the type II collagen degradation marker CTX-II is increased in postmenopausal women and in ovariectomised rats, suggesting that oestrogen deprivation induces cartilage breakdown. Here we investigate whether this response to oestrogen is also true for other type II collagen...

  5. Priming Adipose-Derived Mesenchymal Stem Cells with Hyaluronan Alters Growth Kinetics and Increases Attachment to Articular Cartilage

    Directory of Open Access Journals (Sweden)

    Peter Succar

    2016-01-01

    Full Text Available Background. Biological therapeutics such as adipose-derived mesenchymal stem cell (MSC therapy are gaining acceptance for knee-osteoarthritis (OA treatment. Reports of OA-patients show reductions in cartilage defects and regeneration of hyaline-like-cartilage with MSC-therapy. Suspending MSCs in hyaluronan commonly occurs in animals and humans, usually without supporting data. Objective. To elucidate the effects of different concentrations of hyaluronan on MSC growth kinetics. Methods. Using a range of hyaluronan concentrations, we measured MSC adherence and proliferation on culture plastic surfaces and a novel cartilage-adhesion assay. We employed time-course and dispersion imaging to assess MSC binding to cartilage. Cytokine profiling was also conducted on the MSC-secretome. Results. Hyaluronan had dose-dependent effects on growth kinetics of MSCs at concentrations of entanglement point (1 mg/mL. At higher concentrations, viscosity effects outweighed benefits of additional hyaluronan. The cartilage-adhesion assay highlighted for the first time that hyaluronan-primed MSCs increased cell attachment to cartilage whilst the presence of hyaluronan did not. Our time-course suggested patients undergoing MSC-therapy for OA could benefit from joint-immobilisation for up to 8 hours. Hyaluronan also greatly affected dispersion of MSCs on cartilage. Conclusion. Our results should be considered in future trials with MSC-therapy using hyaluronan as a vehicle, for the treatment of OA.

  6. Regulation of complement by cartilage oligomeric matrix protein allows for a novel molecular diagnostic principle in rheumatoid arthritis

    DEFF Research Database (Denmark)

    Happonen, Kaisa E; Saxne, Tore; Aspberg, Anders;

    2010-01-01

    Cartilage oligomeric matrix protein (COMP) is a structural component of cartilage, where it catalyzes collagen fibrillogenesis. Elevated amounts of COMP are found in serum during increased turnover of cartilage associated with active joint disease, such as rheumatoid arthritis (RA) and osteoarthr......Cartilage oligomeric matrix protein (COMP) is a structural component of cartilage, where it catalyzes collagen fibrillogenesis. Elevated amounts of COMP are found in serum during increased turnover of cartilage associated with active joint disease, such as rheumatoid arthritis (RA) and...

  7. Cartilage Engineering and Microgravity

    Science.gov (United States)

    Toffanin, R.; Bader, A.; Cogoli, A.; Carda, C.; Fantazzini, P.; Garrido, L.; Gomez, S.; Hall, L.; Martin, I.; Murano, E.; Poncelet, D.; Pörtner, R.; Hoffmann, F.; Roekaerts, D.; Ronney, P.; Triebel, W.; Tummers, M.

    2005-06-01

    The complex effects of mechanical forces and growth factors on articular cartilage development still need to be investigated in order to identify optimal conditions for articular cartilage repair. Strictly controlled in vitro studies under modelled or space microgravity conditions can improve our understanding of the fundamental role of gravity in articular cartilage development. The main objective of this Topical Team is to use modelled microgravity as a tool to elucidate the fundamental science of cartilage regeneration. Particular attention is, therefore, given to the effects of physical forces under altered gravitational conditions, applied using controlled bioreactor systems, on cell metabolism, cell differentiation and tissue development. Specific attention is also directed toward the potential advantages of using magnetic resonance methods for the non-destructive characterisation of scaffolds, chondrocytes-polymer constructs and tissue engineered cartilage.

  8. Engineering Cartilage

    Science.gov (United States)

    ... Research Matters NIH Research Matters March 3, 2014 Engineering Cartilage Artistic rendering of human stem cells on ... situations has been a major goal in tissue engineering. Cartilage contains water, collagen, proteoglycans, and chondrocytes. Collagens ...

  9. Psychological stress alters the ultrastructure and increases IL-1β and TNF-α in mandibular condylar cartilage

    Directory of Open Access Journals (Sweden)

    Xin Lv

    2012-10-01

    Full Text Available Psychological factors can be correlated with temporomandibular disorders (TMDs, but the mechanisms are unknown. In the present study, we examined the microstructural changes and expression of proinflammatory cytokines in mandibular condylar cartilage of the temporomandibular joint (TMJ in a psychological stress animal model. Male Sprague-Dawley rats (8 weeks old, 210 ± 10 g were randomly divided into 3 groups: psychological stress (PS, N = 48, foot shock (FS, N = 24, and control (N = 48. After inducing psychological stress using a communication box with the FS rats for 1, 3, or 5 weeks, PS rats were sacrificed and compared to their matched control littermates, which received no stress and were killed at the same times as the PS rats. Body and adrenal gland weight were measured and corticosterone and adrenocorticotropic hormone levels were determined by radioimmunoassay. After hematoxylin-eosin staining for histological observation, the ultrastructure of the TMJ was examined by scanning electron microscopy. Transcription and protein levels of interleukin-1β (IL-1β and tumor necrosis factor-α (TNF-α were evaluated by ELISA and semi-quantitative RT-PCR. The PS group showed a significantly higher adrenal gland weight after 3 weeks of stress and higher hormone levels at weeks 1, 3, and 5. Histopathological changes and thinning cartilage were apparent at weeks 3 and 5. In the PS group, TNF-α increased at 1, 3, and 5 weeks and IL-1β increased significantly after 1 and 3 weeks of stress, and then decreased to normal levels by 5 weeks. Psychological stress increased plasma hormone levels and RT-PCR indicated increased IL-1β and TNF-α expression in the TMJ in a time-dependent manner. These results suggest that cytokine up-regulation was accompanied by stress-induced cartilage degeneration in the mandibular condyle. The proinflammatory cytokines play a potential role in initiating the cartilage destruction that eventually leads to the TMDs.

  10. Psychological stress alters the ultrastructure and increases IL-1β and TNF-α in mandibular condylar cartilage

    Energy Technology Data Exchange (ETDEWEB)

    Lv, Xin; Li, Qiang; Wu, Shun; Sun, Jing; Zhang, Min; Chen, Yong-Jin [Department of General Dentistry and Emergency, School of Stomatology, Fourth Military Medical University, Xi' an, Shaanxi (China)

    2012-06-22

    Psychological factors can be correlated with temporomandibular disorders (TMDs), but the mechanisms are unknown. In the present study, we examined the microstructural changes and expression of proinflammatory cytokines in mandibular condylar cartilage of the temporomandibular joint (TMJ) in a psychological stress animal model. Male Sprague-Dawley rats (8 weeks old, 210 ± 10 g) were randomly divided into 3 groups: psychological stress (PS, N = 48), foot shock (FS, N = 24), and control (N = 48). After inducing psychological stress using a communication box with the FS rats for 1, 3, or 5 weeks, PS rats were sacrificed and compared to their matched control littermates, which received no stress and were killed at the same times as the PS rats. Body and adrenal gland weight were measured and corticosterone and adrenocorticotropic hormone levels were determined by radioimmunoassay. After hematoxylin-eosin staining for histological observation, the ultrastructure of the TMJ was examined by scanning electron microscopy. Transcription and protein levels of interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α) were evaluated by ELISA and semi-quantitative RT-PCR. The PS group showed a significantly higher adrenal gland weight after 3 weeks of stress and higher hormone levels at weeks 1, 3, and 5. Histopathological changes and thinning cartilage were apparent at weeks 3 and 5. In the PS group, TNF-α increased at 1, 3, and 5 weeks and IL-1β increased significantly after 1 and 3 weeks of stress, and then decreased to normal levels by 5 weeks. Psychological stress increased plasma hormone levels and RT-PCR indicated increased IL-1β and TNF-α expression in the TMJ in a time-dependent manner. These results suggest that cytokine up-regulation was accompanied by stress-induced cartilage degeneration in the mandibular condyle. The proinflammatory cytokines play a potential role in initiating the cartilage destruction that eventually leads to the TMDs.

  11. Psychological stress alters the ultrastructure and increases IL-1β and TNF-α in mandibular condylar cartilage

    International Nuclear Information System (INIS)

    Psychological factors can be correlated with temporomandibular disorders (TMDs), but the mechanisms are unknown. In the present study, we examined the microstructural changes and expression of proinflammatory cytokines in mandibular condylar cartilage of the temporomandibular joint (TMJ) in a psychological stress animal model. Male Sprague-Dawley rats (8 weeks old, 210 ± 10 g) were randomly divided into 3 groups: psychological stress (PS, N = 48), foot shock (FS, N = 24), and control (N = 48). After inducing psychological stress using a communication box with the FS rats for 1, 3, or 5 weeks, PS rats were sacrificed and compared to their matched control littermates, which received no stress and were killed at the same times as the PS rats. Body and adrenal gland weight were measured and corticosterone and adrenocorticotropic hormone levels were determined by radioimmunoassay. After hematoxylin-eosin staining for histological observation, the ultrastructure of the TMJ was examined by scanning electron microscopy. Transcription and protein levels of interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α) were evaluated by ELISA and semi-quantitative RT-PCR. The PS group showed a significantly higher adrenal gland weight after 3 weeks of stress and higher hormone levels at weeks 1, 3, and 5. Histopathological changes and thinning cartilage were apparent at weeks 3 and 5. In the PS group, TNF-α increased at 1, 3, and 5 weeks and IL-1β increased significantly after 1 and 3 weeks of stress, and then decreased to normal levels by 5 weeks. Psychological stress increased plasma hormone levels and RT-PCR indicated increased IL-1β and TNF-α expression in the TMJ in a time-dependent manner. These results suggest that cytokine up-regulation was accompanied by stress-induced cartilage degeneration in the mandibular condyle. The proinflammatory cytokines play a potential role in initiating the cartilage destruction that eventually leads to the TMDs

  12. Cathepsin-Mediated Alterations in TGFß-Related Signaling Underlie Disrupted Cartilage and Bone Maturation Associated With Impaired Lysosomal Targeting.

    Science.gov (United States)

    Flanagan-Steet, Heather; Aarnio, Megan; Kwan, Brian; Guihard, Pierre; Petrey, Aaron; Haskins, Mark; Blanchard, Frederic; Steet, Richard

    2016-03-01

    Hypersecretion of acid hydrolases is a hallmark feature of mucolipidosis II (MLII), a lysosomal storage disease caused by loss of carbohydrate-dependent lysosomal targeting. Inappropriate extracellular action of these hydrolases is proposed to contribute to skeletal pathogenesis, but the mechanisms that connect hydrolase activity to the onset of disease phenotypes remain poorly understood. Here we link extracellular cathepsin K activity to abnormal bone and cartilage development in MLII animals by demonstrating that it disrupts the balance of TGFß-related signaling during chondrogenesis. TGFß-like Smad2,3 signals are elevated and BMP-like Smad1,5,8 signals reduced in both feline and zebrafish MLII chondrocytes and osteoblasts, maintaining these cells in an immature state. Reducing either cathepsin K activity or expression of the transcriptional regulator Sox9a in MLII zebrafish significantly improved phenotypes. We further identify components of the large latent TGFß complex as novel targets of cathepsin K at neutral pH, providing a possible mechanism for enhanced Smad2,3 activation in vivo. These findings highlight the complexity of the skeletal disease associated with MLII and bring new insight to the role of secreted cathepsin proteases in cartilage development and growth factor regulation. © 2015 American Society for Bone and Mineral Research. PMID:26404503

  13. Increased bone density and decreased bone turnover, but no evident alteration of fracture susceptibility in elderly women with diabetes mellitus.

    Science.gov (United States)

    Gerdhem, P; Isaksson, A; Akesson, K; Obrant, Karl J

    2005-12-01

    Bone density, bone turnover and fracture susceptibility were evaluated in 1,132 randomly recruited women, all 75 years old. Seventy-four of the women had diabetes, while 1,058 women did not. Areal bone mineral density (aBMD) of the hip and lumbar spine was investigated by dual energy X-ray absorptiometry (DXA), and bone mass of the calcaneus was measured by ultrasound. Urinary deoxypyridinoline/creatinine (U-DPD/Crea) and serum C-terminal cross-linked telopeptide of type 1 collagen (S-CTX) were assessed as markers of bone resorption. Serum bone-specific alkaline phosphatase (S-bone ALP) and serum osteocalcin (S-OC) were assessed as markers of bone formation. Also, serum 25(OH) vitamin D and serum parathyroid hormone (S-PTH) were assessed. Fracture susceptibility was evaluated retrospectively and prospectively for up to 6.5 years. In diabetic women, the aBMD of the femoral neck was 11% higher (pCrea, S-CTX, and S-OC were decreased when compared with non-diabetic women (p=0.001 or less). After correction for covariance of body weight and plasma creatinine, S-CTX (p<0.001) and S-OC (p<0.001) were still lower in the diabetic women. Diabetic patients had hypovitaminosis D (p=0.008), a difference explained by differences in time spent outdoors and body weight. S-PTH did not differ between the groups. Women with diabetes had no more lifetime fractures (52%) than women without diabetic disease (57%), (p=0.31). This study shows that elderly women with diabetes and without severe renal insufficiency have high bone mass and low bone turnover. The high bone mass and low bone turnover is not likely to have a strong influence on fracture susceptibility. PMID:15824889

  14. Splenectomy alters distribution and turnover but not numbers or protective capacity of de novo generated memory CD8 T cells.

    Directory of Open Access Journals (Sweden)

    Marie eKim

    2014-11-01

    Full Text Available The spleen is a highly compartmentalized lymphoid organ that allows for efficient antigen presentation and activation of immune responses. Additionally, the spleen itself functions to remove senescent red blood cells, filter bacteria, and sequester platelets. Splenectomy, commonly performed after blunt force trauma or splenomegaly, has been shown to increase risk of certain bacterial and parasitic infections years after removal of the spleen. Although previous studies report defects in memory B cells and IgM titers in splenectomized patients, the effect of splenectomy on CD8 T cell responses and memory CD8 T cell function remains ill defined. Using TCR-transgenic P14 cells, we demonstrate that homeostatic proliferation and representation of pathogen-specific memory CD8 T cells in the blood are enhanced in splenectomized compared to sham surgery mice. Surprisingly, despite the enhanced turnover, splenectomized mice displayed no changes in total memory CD8 T cell numbers nor impaired protection against lethal dose challenge with Listeria monocytogenes. Thus, our data suggest that memory CD8 T cell maintenance and function remain intact in the absence of the spleen.

  15. Pharmacological PPARα activation markedly alters plasma turnover of the amino acids glycine, serine and arginine in the rat.

    Directory of Open Access Journals (Sweden)

    Anette Ericsson

    Full Text Available The current study extends previously reported PPARα agonist WY 14,643 (30 µmol/kg/day for 4 weeks effects on circulating amino acid concentrations in rats fed a 48% saturated fat diet. Steady-state tracer experiments were used to examine in vivo kinetic mechanisms underlying altered plasma serine, glycine and arginine levels. Urinary urea and creatinine excretion were measured to assess whole-body amino acid catabolism. WY 14,643 treated animals demonstrated reduced efficiency to convert food consumed to body weight gain while liver weight was increased compared to controls. WY 14,643 raised total amino acid concentration (38%, largely explained by glycine, serine and threonine increases. 3H-glycine, 14C-serine and 14C-arginine tracer studies revealed elevated rates of appearance (Ra for glycine (45.5 ± 5.8 versus 17.4 ± 2.7 µmol/kg/min and serine (21.0 ± 1.4 versus 12.0 ± 1.0 in WY 14,643 versus control. Arginine was substantially decreased (-62% in plasma with estimated Ra reduced from 3.1 ± 0.3 to 1.2 ± 0.2 µmol/kg/min in control versus WY 14,643. Nitrogen excretion over 24 hours was unaltered. Hepatic arginase activity was substantially decreased by WY 14,643 treatment. In conclusion, PPARα agonism potently alters metabolism of several specific amino acids in the rat. The changes in circulating levels of serine, glycine and arginine reflected altered fluxes into the plasma rather than changes in clearance or catabolism. This suggests that PPARα has an important role in modulating serine, glycine and arginine de novo synthesis.

  16. Biochemical Markers of Joint Tissue Turnover

    DEFF Research Database (Denmark)

    Bay-Jensen, Anne-Christine; Sondergaard, Bodil Cecilie; Christiansen, Claus;

    2009-01-01

    available for the study of tissue turnover in each of the three compartments of the articular joint, that is the bone, the cartilage, and the synovium. Finally, we provide some perspective to future developments in biomarker discovery and discuss the potential impact such technologies could have on the drug...

  17. Role of Chondrocytes in Cartilage Formation, Progression of Osteoarthritis and Cartilage Regeneration

    Science.gov (United States)

    Akkiraju, Hemanth; Nohe, Anja

    2016-01-01

    Articular cartilage (AC) covers the diarthrodial joints and is responsible for the mechanical distribution of loads across the joints. The majority of its structure and function is controlled by chondrocytes that regulate Extracellular Matrix (ECM) turnover and maintain tissue homeostasis. Imbalance in their function leads to degenerative diseases like Osteoarthritis (OA). OA is characterized by cartilage degradation, osteophyte formation and stiffening of joints. Cartilage degeneration is a consequence of chondrocyte hypertrophy along with the expression of proteolytic enzymes. Matrix Metalloproteinases (MMPs) and A Disintegrin and Metalloproteinase with Thrombospondin Motifs (ADAMTS) are an example of these enzymes that degrade the ECM. Signaling cascades involved in limb patterning and cartilage repair play a role in OA progression. However, the regulation of these remains to be elucidated. Further the role of stem cells and mature chondrocytes in OA progression is unclear. The progress in cell based therapies that utilize Mesenchymal Stem Cell (MSC) infusion for cartilage repair may lead to new therapeutics in the long term. However, many questions are unanswered such as the efficacy of MSCs usage in therapy. This review focuses on the role of chondrocytes in cartilage formation and the progression of OA. Moreover, it summarizes possible alternative therapeutic approaches using MSC infusion for cartilage restoration. PMID:27347486

  18. Turnover Time

    Science.gov (United States)

    Ecosystems contain energy and materials such as carbon, nitrogen, phosphorus, and water, and are open to their flow-through. Turnover time refers to the amount of time required for replacement by flow-through of the energy or substance of interest contained in the system, and is ...

  19. Imaging of articular cartilage

    Directory of Open Access Journals (Sweden)

    Bhawan K Paunipagar

    2014-01-01

    Full Text Available We tried to review the role of magnetic resonance imaging (MRI in understanding microscopic and morphologic structure of the articular cartilage. The optimal protocols and available spin-echo sequences in present day practice are reviewed in context of common pathologies of articular cartilage. The future trends of articular cartilage imaging have been discussed with their appropriateness. In diarthrodial joints of the body, articular cartilage is functionally very important. It is frequently exposed to trauma, degeneration, and repetitive wear and tear. MRI has played a vital role in evaluation of articular cartilage. With the availability of advanced repair surgeries for cartilage lesions, there has been an increased demand for improved cartilage imaging techniques. Recent advances in imaging strategies for native and postoperative articular cartilage open up an entirely new approach in management of cartilage-related pathologies.

  20. Cartilage (Bovine and Shark) (PDQ)

    Science.gov (United States)

    ... Ask about Your Treatment Research Cartilage (Bovine and Shark) (PDQ®)–Patient Version Overview Go to Health Professional ... 8 ). Questions and Answers About Cartilage (Bovine and Shark) What is cartilage? Cartilage is a type of ...

  1. Early detection and monitoring of cartilage alteration in the experimental meniscectomised guinea pig model of osteoarthritis by 99mTc-NTP 15-5 scintigraphy

    International Nuclear Information System (INIS)

    This study in the meniscectomised guinea pig aimed to demonstrate that the radiotracer 99mTc-NTP 15-5 would have pathophysiological validity for in vivo osteoarthritis imaging. The specificity of 99mTc-NTP 15-5 for cartilage was determined in healthy animals (n = 13), by tissue radioactivity counting, joint autoradiography and scintigraphy. 99mTc-NTP 15-5 scintigraphy was performed at 20, 50, 80, 115, 130, 150 and 180 days after medial meniscectomy (n = 10 MNX) or sham operation (n = 5), and scintigraphic ratios (operated/contralateral) were calculated for femoral (F) and tibial (T) areas. F and T ratios were compared with those of 99mTc-MDP bone scintigraphy. At the study end-point, autoradiographic analysis of joint 99mTc-NTP 15-5 distribution and macroscopic scoring of cartilage integrity were performed. The high and specific accumulation of 99mTc-NTP 15-5 in normal cartilage (about 5.5 ± 1.7 % of injected dose/g of tissue), which permitted joint imaging with high contrast, was affected by osteoarthritis. In the MNX group, 99mTc-NTP 15-5 accumulation in cartilage within the operated joint, relative to the contralateral joint, was observed to change in the same animals as pathology progressed. Although F and T ratios were significantly higher in MNX (F = 1.7 ± 0.2; T = 1.6 ± 0.1) than in shams (F = 1.0 ± 0.1; T = 1.0 ± 0.1) at day 50, they were significantly lower in MNX (F = 0.6 ± 0.1; T = 0.7 ± 0.1) than in shams (F = 1.0 ± 0.1; T = 0.9 ± 0.1) at day 180. No change in 99mTc-MDP uptake was observed over 6 months. Macroscopic analysis confirmed features of osteoarthritis only in MNX knees. These results in MNX guinea pigs provide additional support for the use of 99mTc-NTP 15-5 for in vivo imaging of osteoarthritis. (orig.)

  2. Lubricin reduces cartilage--cartilage integration.

    Science.gov (United States)

    Schaefer, Dirk B; Wendt, David; Moretti, Matteo; Jakob, Marcel; Jay, Gregory D; Heberer, Michael; Martin, Ivan

    2004-01-01

    Cartilage integration in vivo does not occur, such that even cartilage fissures do not heal. This could be due not only to the limited access of chondrocytes to the wound, but also to exogenous factors. In this paper, we tested the hypothesis that lubricin, a lubricating protein physiologically present in the synovial fluid, reduces the integrative cartilage repair capacity. Disk/ring composites of bovine articular cartilage were prepared using concentric circular blades and cultured for 6 weeks with or without treatment with 250 microg/ml lubricin applied three times per week. Following culture, the percentage of contact area between the disks and the rings, as assessed by light microscopy, were equal in both groups. The adhesive strength of the integration interface, as assessed by push-out mechanical tests, was markedly and significantly lower in lubricin-treated specimens (2.5 kPa) than in the controls (28.7 kPa). Histological observation of Safranin-O stained cross-sections confirmed the reduced integration in the lubricin treated composites. Our findings suggest that the synovial milieu, by providing lubrication of cartilage surfaces, impairs cartilage--cartilage integration. PMID:15299281

  3. Mammary Carcinogenesis Is Preceded by Altered Epithelial Cell Turnover in Transforming Growth Factor-α and c-myc Transgenic Mice

    OpenAIRE

    Rose-Hellekant, Teresa A; Wentworth, Kristin M.; Nikolai, Sarah; Kundel, Donald W.; Sandgren, Eric P.

    2006-01-01

    Identification of biomarkers that indicate an increased risk of breast cancer or that can be used as surrogates for evaluating treatment efficacy is paramount to successful disease prevention and intervention. An ideal biomarker would be identifiable before lesion development. To test the hypothesis that changes in cell turnover precede mammary carcinogenesis, we evaluated epithelial cell proliferation and apoptosis in mammary glands from transgenic mice engineered to develop mammary cancer d...

  4. Adult-Onset Deficiency in Growth Hormone and Insulin-Like Growth Factor-I Alters Oligodendrocyte Turnover in the Corpus Callosum

    OpenAIRE

    Hua, Kun; Forbes, M. Elizabeth; Lichtenwalner, Robin J.; Sonntag, William E.; Riddle, David R.

    2009-01-01

    Growth hormone (GH) and insulin-like growth factor-I (IGF-I) provide trophic support during development and also appear to influence cell structure, function and replacement in the adult brain. Recent studies demonstrated effects of the GH/IGF-I axis on adult neurogenesis, but it is unclear whether the GH/IGF-I axis influences glial turnover in the normal adult brain. In the current study we used a selective model of adult-onset GH and IGF-I deficiency to evaluate the role of GH and IGF-I in ...

  5. Cartilage conduction hearing.

    Science.gov (United States)

    Shimokura, Ryota; Hosoi, Hiroshi; Nishimura, Tadashi; Yamanaka, Toshiaki; Levitt, Harry

    2014-04-01

    Sound information is known to travel to the cochlea via either air or bone conduction. However, a vibration signal, delivered to the aural cartilage via a transducer, can also produce a clearly audible sound. This type of conduction has been termed "cartilage conduction." The aural cartilage forms the outer ear and is distributed around the exterior half of the external auditory canal. In cartilage conduction, the cartilage and transducer play the roles of a diaphragm and voice coil of a loudspeaker, respectively. There is a large gap between the impedances of cartilage and skull bone, such that cartilage vibrations are not easily transmitted through bone. Thus, these methods of conduction are distinct. In this study, force was used to apply a transducer to aural cartilage, and it was found that the sound in the auditory canal was amplified, especially for frequencies below 2 kHz. This effect was most pronounced at an application force of 1 N, which is low enough to ensure comfort in the design of hearing aids. The possibility of using force adjustments to vary amplification may also have applications for cell phone design. PMID:25234994

  6. Oxygen, nitric oxide and articular cartilage

    Directory of Open Access Journals (Sweden)

    B Fermor

    2007-04-01

    Full Text Available Molecular oxygen is required for the production of nitric oxide (NO, a pro-inflammatory mediator that is associated with osteoarthritis and rheumatoid arthritis. To date there has been little consideration of the role of oxygen tension in the regulation of nitric oxide production associated with arthritis. Oxygen tension may be particularly relevant to articular cartilage since it is avascular and therefore exists at a reduced oxygen tension. The superficial zone exists at approximately 6% O2, while the deep zone exists at less than 1% O2. Furthermore, oxygen tension can alter matrix synthesis, and the material properties of articular cartilage in vitro.The increase in nitric oxide associated with arthritis can be caused by pro-inflammatory cytokines and mechanical stress. Oxygen tension significantly alters endogenous NO production in articular cartilage, as well as the stimulation of NO in response to both mechanical loading and pro-inflammatory cytokines. Mechanical loading and pro-inflammatory cytokines also increase the production of prostaglandin E2 (PGE2. There is a complex interaction between NO and PGE2, and oxygen tension can alter this interaction. These findings suggest that the relatively low levels of oxygen within the joint may have significant influences on the metabolic activity, and inflammatory response of cartilage as compared to ambient levels. A better understanding of the role of oxygen in the production of inflammatory mediators in response to mechanical loading, or pro-inflammatory cytokines, may aid in the development of strategies for therapeutic intervention in arthritis.

  7. MRI of the cartilage

    International Nuclear Information System (INIS)

    With the introduction of fat-suppressed gradient-echo and fast spin-echo (FSE) sequences in clinical routine MR visualization of the hyaline articular cartilage is routinely possible in the larger joints. While 3D gradient-echo with fat suppression allows exact depiction of the thickness and surface of cartilage, FSE outlines the normal and abnormal internal structures of the hyaline cartilage; therefore, both sequences seem to be necessary in a standard MRI protocol for cartilage visualization. In diagnostically ambiguous cases, in which important therapeutic decisions are required, direct MR arthrography is the established imaging standard as an add-on procedure. Despite the social impact and prevalence, until recent years there was a paucity of knowledge about the pathogenesis of cartilage damage. With the introduction of high-resolution MRI with powerful surface coils and fat-suppression techniques, visualization of the articular cartilage is now routinely possible in many joints. After a short summary of the anatomy and physiology of the hyaline cartilage, the different MR imaging methods are discussed and recommended standards are suggested. (orig.)

  8. Global Foreign Exchange Turnover

    OpenAIRE

    Crystal Ossolinski; Andrew Zurawski

    2010-01-01

    The most recent six-monthly data on global foreign exchange turnover show a rebound in activity between April and October 2009 across all markets and major currency pairs. The broad-based increase in turnover is in line with the improvement in global economic and financial conditions since early 2009. Despite the rebound, turnover remains below the peak in early 2008.

  9. Reversible alterations in epithelial cell turnover in digestive gland of winkles (Littorina littorea) exposed to cadmium and their implications for biomarker measurements

    Energy Technology Data Exchange (ETDEWEB)

    Zaldibar, B. [Cell Biology and Histology Laboratory, Zoology and Animal Cell Biology Department, School of Science and Technology, University of the Basque Country, PO Box 644, E-48080 Bilbo, Basque Country (Spain); Cancio, I. [Cell Biology and Histology Laboratory, Zoology and Animal Cell Biology Department, School of Science and Technology, University of the Basque Country, PO Box 644, E-48080 Bilbo, Basque Country (Spain); Marigomez, I. [Cell Biology and Histology Laboratory, Zoology and Animal Cell Biology Department, School of Science and Technology, University of the Basque Country, PO Box 644, E-48080 Bilbo, Basque Country (Spain)]. E-mail: ionan.marigomez@ehu.es

    2007-02-28

    In marine molluscs, the epithelium of the digestive gland is composed of two cell types, namely, digestive and basophilic cells. Under normal physiological conditions digestive cells outnumber basophilic cells, but under different stress situations the composition of the epithelium changes, basophilic cells apparently replace digestive cell. Winkles, Littorina littorea, were exposed to 1.25 mg/l Cd for 20 days to provoke cell type replacement. Then, animals were depurated in clean seawater for 10 days to determine whether cell type replacement was reversible. Digestive glands were fixed in Carnoy and paraffin embedded for histological analysis. The volume densities of basophilic cells (Vv{sub BAS}) and digestive cells (Vv{sub DIG}) were calculated by stereology on hematoxylin-eosin stained sections. Vv{sub BAS} increased and Vv{sub DIG} decreased in Cd-exposed animals. After estimation of cell size and absolute cell numbers, these changes were attributed to digestive cell loss and concomitant basophilic cell hypertrophy but not to increased numbers of basophilic cells. Cell type composition and cell size almost fully returned to normal values after 10-day depuration. Accordingly, PCNA immunohistochemistry demonstrated that proliferating digestive cells were more abundant in winkles exposed to Cd and after 10-day depuration than in control specimens, suggesting that net digestive cell loss was accompanied by increased digestive cell proliferation. Thus, Cd-exposure seems to provoke an enhanced digestive cell turnover in order to cope with Cd detoxification. Intralysosomal accumulation of metals (autometallographied black silver deposits; BSD) was used as a biomarker of exposure to Cd and lysosomal structural changes as an effect biomarker to see whether cell type composition might have any effect on these endpoints. BSD formed around Cd ions, in digestive cell lysosomes of Cd-exposed winkles whereas basophilic cells appeared devoid of them. After depuration, BSD

  10. Distribution of MRI signal alterations of the cartilage endplate in pre-operated patients with special focus on recurrent lumbar disc herniation; Verteilungsmuster von (Modic-)Signalveraenderungen an den vertebralen Endplatten voroperierter Patienten und ihr Bezug zu Rezidivvorfaellen

    Energy Technology Data Exchange (ETDEWEB)

    Becker, G.T.; Liphofer, J.; Koester, O. [Inst. fuer Diagnostische und Interventionelle Radiologie und Nuklearmedizin, St. Josef-Hospital, Bochum (Germany); Willburger, R.E. [Abt. fuer Rheumaorthopaedie, St. Elisabeth-Hospital, Bochum (Germany); Schmid, G. [Klinik fuer Diagnostische und Interventionelle Radiologie, Johanna-Etienne-Krankenhaus, Neuss (Germany)

    2006-01-01

    Purpose: To study the location of (Modic) MR signal alterations (SA) of the cartilage endplate (CEP) in pre- and non-operated segments L3-S1 with special focus on the presence of recurrent lumbar disc herniation (RLDH). Materials and Methods: In a retrospective study the MR images of vertebrae L3-S1 of 65 consecutive patients with a history of microdiscectomy were evaluated. Of the 190 segments studied, 67 were pre-operated. These were divided into a group with recurrent lumbar disc herniation (RLDH) (n=19) and a group without evidence of RLDH (n=48). Non-operated segments (n=123) were also considered as a separate group. In these three groups the prevalence of different Modic types was determined using the sag. T1- and T2-weighted images, and, in particular, the distribution of SA at the upper and lower CEP was examined by evaluating the sag. T2-weighted images. In order to achieve this, each CEP was divided into nine regions. Results: Pre-operated segments showed significantly more frequent (p<0.001) and more expansive (p<0.001) SA than non-operated segments. Non-operated segments showed SA less frequently in the central region of both upper and lower CEP (p=0.056 and p=0.015, respectively). In operated segments without RLDH, the upper CEP had significantly more SA on the operation side than in the mid-sagittal and contra-lateral regions (p=0.016, p=0.037) and significantly more on the operation side of the lower CEP than in the contra-lateral region (p=0.027). Operated segments with RLDH did not show an emphasis of SA on the operation side. In this group SA occurred significantly more often in the central and ventral mid-sagittal regions of the upper CEP than in the preoperated segments without RLDH. (orig.)

  11. Regulatory mechanisms of skeletal muscle protein turnover during exercise

    DEFF Research Database (Denmark)

    Rose, Adam John; Richter, Erik

    2009-01-01

    downstream of changes in intracellular Ca(2+) and energy turnover. In particular, a signaling cascade involving Ca(2+)-calmodulin-eEF2 kinase-eEF2 is implicated. The possible functional significance of altered protein turnover in working skeletal muscle during exercise is discussed. Further work with...... available and new techniques will undoubtedly reveal the functional significance and signaling mechanisms behind changes in skeletal muscle protein turnover during exercise. Key words: Exercise, skeletal muscle, protein metabolism, translation....

  12. Chondroptosis in alkaptonuric cartilage.

    Science.gov (United States)

    Millucci, Lia; Giorgetti, Giovanna; Viti, Cecilia; Ghezzi, Lorenzo; Gambassi, Silvia; Braconi, Daniela; Marzocchi, Barbara; Paffetti, Alessandro; Lupetti, Pietro; Bernardini, Giulia; Orlandini, Maurizio; Santucci, Annalisa

    2015-05-01

    Alkaptonuria (AKU) is a rare genetic disease that affects the entire joint. Current standard of treatment is palliative and little is known about AKU physiopathology. Chondroptosis, a peculiar type of cell death in cartilage, has been so far reported to occur in osteoarthritis, a rheumatic disease that shares some features with AKU. In the present work, we wanted to assess if chondroptosis might also occur in AKU. Electron microscopy was used to detect the morphological changes of chondrocytes in damaged cartilage distinguishing apoptosis from its variant termed chondroptosis. We adopted histological observation together with Scanning Electron Microscopy and Transmission Electron Microscopy to evaluate morphological cell changes in AKU chondrocytes. Lipid peroxidation in AKU cartilage was detected by fluorescence microscopy. Using the above-mentioned techniques, we performed a morphological analysis and assessed that AKU chondrocytes undergo phenotypic changes and lipid oxidation, resulting in a progressive loss of articular cartilage structure and function, showing typical features of chondroptosis. To the best of our knowledge, AKU is the second chronic pathology, following osteoarthritis, where chondroptosis has been documented. Our results indicate that Golgi complex plays an important role in the apoptotic process of AKU chondrocytes and suggest a contribution of chondroptosis in AKU pathogenesis. These findings also confirm a similarity between osteoarthritis and AKU. PMID:25336110

  13. Fracture of articular cartilage.

    Science.gov (United States)

    Chin-Purcell, M V; Lewis, J L

    1996-11-01

    Crack formation and propagation is a significant element of the degeneration process in articular cartilage. In order to understand this process, and separate the relative importance of structural overload and material failure, methods for measuring the fracture toughness of cartilage are needed. In this paper, two such methods are described and used to measure fracture properties of cartilage from the canine patella. A modified single edge notch (MSEN) specimen was used to measure J, and a trouser tear test was used to measure T, both measures of fracture toughness with units of kN/m. A pseudo-elastic modulus was also obtained from the MSEN test. Several potential error sources were examined, and results for the MSEN test compared with another method for measuring the fracture parameter for urethane rubber. Good agreement was found. The two test methods were used to measure properties of cartilage from the patellae of 12 canines: 4-9 specimens from each of 12 patellae, with 5 right-left pairs were tested. Values of J ranged from 0.14-1.2 kN/m. J values correlated with T and were an average of 1.7 times larger than T. A variety of failure responses was seen in the MSEN tests, consequently a grade of 0 to 3 was assigned to each test, where 0 represented a brittle-like crack with minimal opening and 3 represented plastic flow with no crack formation. The initial cracks in 12/82 specimens did not propagate and were assigned to grade 3. The method for reducing data in the MSEN test assumed pseudo-elastic response and could not be used for the grade 3 specimens. Stiffness did not correlate with J. Neither J nor T was statistically different between right-left pairs, but varied between animals. The test methods appear useful for providing a quantitative measure of fracture toughness for cartilage and other soft materials. PMID:8950659

  14. Lubricin is expressed in chondrocytes derived from osteoarthritic cartilage encapsulated in poly(ethylene glycol diacrylate scaffold

    Directory of Open Access Journals (Sweden)

    G. Musumeci

    2011-09-01

    Full Text Available Osteoarthritis (OA is characterized by degenerative changes within joints that involved quantitative and/or qualitative alterations of cartilage and synovial fluid lubricin, a mucinous glycoprotein secreted by synovial fibroblasts and chondrocytes. Modern therapeutic methods, including tissue-engineering techniques, have been used to treat mechanical damage of the articular cartilage but to date there is no specific and effective treatment. This study aimed at investigating lubricin immunohistochemical expression in cartilage explant from normal and OA patients and in cartilage constructions formed by Poly (ethylene glycol (PEG based hydrogels (PEG-DA encapsulated OA chondrocytes. The expression levels of lubricin were studied by immunohistochemistry: i in tissue explanted from OA and normal human cartilage; ii in chondrocytes encapsulated in hydrogel PEGDA from OA and normal human cartilage. Moreover, immunocytochemical and western blot analysis were performed in monolayer cells from OA and normal cartilage. The results showed an increased expression of lubricin in explanted tissue and in monolayer cells from normal cartilage, and a decreased expression of lubricin in OA cartilage. The chondrocytes from OA cartilage after 5 weeks of culture in hydrogels (PEGDA showed an increased expression of lubricin compared with the control cartilage. The present study demonstrated that OA chondrocytes encapsulated in PEGDA, grown in the scaffold and were able to restore lubricin biosynthesis. Thus our results suggest the possibility of applying autologous cell transplantation in conjunction with scaffold materials for repairing cartilage lesions in patients with OA to reduce at least the progression of the disease.

  15. Cartilage analysis by reflection spectroscopy

    Science.gov (United States)

    Laun, T.; Muenzer, M.; Wenzel, U.; Princz, S.; Hessling, M.

    2015-07-01

    A cartilage bioreactor with analytical functions for cartilage quality monitoring is being developed. For determining cartilage composition, reflection spectroscopy in the visible (VIS) and near infrared (NIR) spectral region is evaluated. Main goal is the determination of the most abundant cartilage compounds water, collagen I and collagen II. Therefore VIS and NIR reflection spectra of different cartilage samples of cow, pig and lamb are recorded. Due to missing analytical instrumentation for identifying the cartilage composition of these samples, typical literature concentration values are used for the development of chemometric models. In spite of these limitations the chemometric models provide good cross correlation results for the prediction of collagen I and II and water concentration based on the visible and the NIR reflection spectra.

  16. Articular cartilage stem cell signalling

    OpenAIRE

    Karlsson, Camilla; Lindahl, Anders

    2009-01-01

    The view of articular cartilage as a non-regeneration organ has been challenged in recent years. The articular cartilage consists of distinct zones with different cellular and molecular phenotypes, and the superficial zone has been hypothesized to harbour stem cells. Furthermore, the articular cartilage demonstrates a distinct pattern regarding stem cell markers (that is, Notch-1, Stro-1, and vascular cell adhesion molecule-1). These results, in combination with the positive identification of...

  17. Transcriptomic profiling of cartilage ageing

    OpenAIRE

    Mandy Jayne Peffers; Xuan Liu; Peter David Clegg

    2014-01-01

    The musculoskeletal system is severely affected by the ageing process, with many tissues undergoing changes that lead to loss of function and frailty. Articular cartilage is susceptible to age related diseases, such as osteoarthritis. Applying RNA-Seq to young and old equine cartilage, we identified an over-representation of genes with reduced expression relating to extracellular matrix, degradative proteases, matrix synthetic enzymes, cytokines and growth factors in cartilage from older dono...

  18. Nanoparticles for diagnostics and laser medical treatment of cartilage in orthopaedics

    Science.gov (United States)

    Baum, O. I.; Soshnikova, Yu. M.; Omelchenko, A. I.; Sobol, Emil

    2013-02-01

    Laser reconstruction of intervertebral disc (LRD) is a new technique which uses local, non-destructive laser irradiation for the controlled activation of regenerative processes in a targeted zone of damaged disc cartilage. Despite pronounced advancements of LRD, existing treatments may be substantially improved if laser radiation is absorbed near diseased and/or damaged regions in cartilage so that required thermomechanical stress and strain at chondrocytes may be generated and non-specific injury reduced or eliminated. The aims of the work are to study possibility to use nanoparticles (NPs) to provide spatial specificity for laser regeneration of cartilage. Two types of porcine joint cartilage have been impregnated with magnetite NPs: 1) fresh cartilage; 2) mechanically damaged cartilage. NPs distribution was studied using transition electron microscopy, dynamic light scattering and analytical ultracentrifugation techniques. Laser radiation and magnetic field have been applied to accelerate NPs impregnation. It was shown that NPs penetrate by diffusion into the mechanically damaged cartilage, but do not infiltrate healthy cartilage. Temperature dynamics in cartilage impregnated with NPs have been theoretically calculated and measurements using an IR thermo vision system have been performed. Laser-induced alterations of cartilage structure and cellular surviving have been studied for cartilage impregnated with NPs using histological and histochemical techniques. Results of our study suggest that magnetite NPs might be used to provide spatial specificity of laser regeneration. When damaged, the regions of cartilage impreganted with NPs have higher absorption of laser radiation than that for healthy areas. Regions containing NPs form target sites that can be used to generate laser-induced thermo mechanical stress leading to regeneration of cartilage of hyaline type.

  19. Fe (Plasma Iron Turnover)

    OpenAIRE

    Montanaro, Zac Kime

    2011-01-01

    Fe (Plasma Iron Turnover) is a work, or compilation of interrelating works, endeavoring to generate a custom strategy for conducting experimental information exploration. Beginning with a single event in world news, the explosion of a gas plant in Western Australia in June of 2008, Fe (Plasma Iron Turnover) teases out the physical, contextual, and subtextual cues of the story to develop and articulate a methodology for discovering related events, both backwards and forwards in history, and fo...

  20. Time-of-flight secondary ion mass spectrometry-based molecular distribution distinguishing healthy and osteoarthritic human cartilage

    CERN Document Server

    Cillero-Pastor, Berta; Kiss, Andras; Blanco, Francisco J; Heeren, Ron M A

    2013-01-01

    Osteoarthritis (OA) is a pathology that ultimately causes joint destruction. The cartilage is one of the principal affected tissues. Alterations in the lipid mediators and an imbalance in the metabolism of cells that form the cartilage (chondrocytes) have been described as contributors to the OA development. In this study, we have studied the distribution of lipids and chemical elements in healthy and OA human cartilage. Time of flight-secondary ion mass spectrometry (TOF-SIMS) allows us to study the spatial distribution of molecules at a high resolution on a tissue section. TOF-SIMS revealed a specific peak profile that distinguishes healthy from OA cartilages. The spatial distribution of cholesterol-related peaks exhibited a remarkable difference between healthy and OA cartilages. A distinctive colocalization of cholesterol and other lipids in the superficial area of the cartilage was found. A higher intensity of oleic acid and other fatty acids in the OA cartilages exhibited a similar localization. On the ...

  1. Differences in Bone Quality between High versus Low Turnover Renal Osteodystrophy

    Energy Technology Data Exchange (ETDEWEB)

    Porter, Daniel S. [University of Kentucky, Lexington; Pienkowski, David [University of Kentucky, Lexington; Faugere, Marie-Claude [Albert B. Chandler Medical Center; Malluche, Hartmut H. [Albert B. Chandler Medical Center

    2012-01-01

    Abnormal bone turnover is common in chronic kidney disease (CKD), but its effects on bone quality remain unclear. This study sought to quantify the relationship between abnormal bone turnover and bone quality. Iliac crest bone biopsies were obtained from CKD-5 patients on dialysis with low (n=18) or high (n=17) turnover, and from volunteers (n=12) with normal turnover and normal kidney function. Histomorphometric methods were used to quantify the microstructural parameters; Fourier transform infrared spectroscopy and nanoindentation were used to quantify the material and mechanical properties in bone. Reduced mineral-to-matrix ratio, mineral crystal size, stiffness and hardness were observed in bone with high turnover compared to bone with normal or low turnover. Decreased cancellous bone volume and trabecular thickness were seen in bone with low turnover compared to bone with normal or high turnover. Bone quality, as defined by its microstructural, material, and mechanical properties, is related to bone turnover. These data suggest that turnover related alterations in bone quality may contribute to the known diminished mechanical competence of bone in CKD patients, albeit from different mechanisms for bone with high (material abnormality) vs. low (microstructural alteration) turnover. The present findings suggest that improved treatments for renal osteodystrophy should seek to avoid low or high bone turnover and aim for turnover rates as close to normal as possible.

  2. The pro-inflammatory cytokine 14-3-3ε is a ligand of CD13 in cartilage

    OpenAIRE

    Nefla, Meriam; Sudre, Laure; Denat, Guillaume; Priam, Sabrina; André-Leroux, Gwenaelle; Jacques, Claire

    2015-01-01

    ABSTRACT Osteoarthritis is a whole-joint disease characterized by the progressive destruction of articular cartilage involving abnormal communication between subchondral bone and cartilage. Our team previously identified 14-3-3ε protein as a subchondral bone soluble mediator altering cartilage homeostasis. The aim of this study was to investigate the involvement of CD13 (also known as aminopeptidase N, APN) in the chondrocyte response to 14-3-3ε. After identifying CD13 in chondrocytes, we kno...

  3. Modeling IL-1 induced degradation of articular cartilage.

    Science.gov (United States)

    Kar, Saptarshi; Smith, David W; Gardiner, Bruce S; Li, Yang; Wang, Yang; Grodzinsky, Alan J

    2016-03-15

    In this study, we develop a computational model to simulate the in vitro biochemical degradation of articular cartilage explants sourced from the femoropatellar grooves of bovine calves. Cartilage explants were incubated in culture medium with and without the inflammatory cytokine IL-1α. The spatio-temporal evolution of the cartilage explant's extracellular matrix components is modelled. Key variables in the model include chondrocytes, aggrecan, collagen, aggrecanase, collagenase and IL-1α. The model is first calibrated for aggrecan homeostasis of cartilage in vivo, then for data on (explant) controls, and finally for data on the IL-1α driven proteolysis of aggrecan and collagen over a 4-week period. The model was found to fit the experimental data best when: (i) chondrocytes continue to synthesize aggrecan during the cytokine challenge, (ii) a one to two day delay is introduced between the addition of IL-1α to the culture medium and subsequent aggrecanolysis, (iii) collagen degradation does not commence until the total concentration of aggrecan (i.e. both intact and degraded aggrecan) at any specific location within the explant becomes ≤1.5 mg/ml and (iv) degraded aggrecan formed due to the IL-1α induced proteolysis of intact aggrecan protects the collagen network while collagen degrades in a two-step process which, together, significantly modulate the collagen network degradation. Under simulated in vivo conditions, the model predicts increased aggrecan turnover rates in the presence of synovial IL-1α, consistent with experimental observations. Such models may help to infer the course of events in vivo following traumatic joint injury, and may also prove useful in quantitatively evaluating the efficiency of various therapeutic molecules that could be employed to avoid or modify the course of cartilage disease states. PMID:26874194

  4. Accelerated extracellular matrix turnover during exacerbations of COPD

    DEFF Research Database (Denmark)

    Sand, Jannie M B; Knox, Alan J; Lange, Peter;

    2015-01-01

    BACKGROUND: Exacerbations of chronic obstructive pulmonary disease (COPD) contribute significantly to disease progression. However, the effect on tissue structure and turnover is not well described. There is an urgent clinical need for biomarkers of disease activity associated with disease...... progression. Extracellular matrix (ECM) turnover reflects activity in tissues and consequently assessment of ECM turnover may serve as biomarkers of disease activity. We hypothesized that the turnover of lung ECM proteins were altered during exacerbations of COPD. METHODS: 69 patients with COPD hospitalised...... elevated levels of circulating fragments of structural proteins, which may serve as markers of disease activity. This suggests that patients with COPD have accelerated ECM turnover during exacerbations which may be related to disease progression....

  5. Shear loading of costal cartilage

    CERN Document Server

    Subit, Damien

    2014-01-01

    A series of tests were performed on a single post-mortem human subject at various length scales. First, tabletop tests were performed. Next, the ribs and intercostal muscles were tested with the view to characterize the load transfer between the ribs. Finally, the costal cartilage was tested under shear loading, as it plays an important in the transfer of the load between the ribs and the sternum. This paper reports the results of dynamic shear loading tests performed on three samples of costal cartilage harvested from a single post-mortem human subject, as well as the quantification of the effective Young's modulus estimated from the amount of cartilage calcification.

  6. Effects of cigarette smoke on the Meckel's cartilage of rat fetus: morphologic, morphometric and stereologic study.

    Science.gov (United States)

    Brandini, Daniela Atili; Sala, Miguel Angel; Lopes, Ruberval Armando; Semprini, Marisa; Contrera, Mary Garcia Duarte

    2005-01-01

    The purpose of this study was to investigate the effects of cigarette smoke on the development of the embryo mandible (Meckel's) cartilage in rat fetuses. When inhaled by female Wistar rats between the 9th and the 12th day of pregnancy, cigarette smoke (5 cigarettes a day) caused intrauterine growth retardation, providing smaller fetuses and placentas. In fetuses from the experimental group, the histopathologic examination revealed a poorly developed Meckel's cartilage with smaller chondroblasts showing a scanty cytoplasm with spherical and paler central nuclei, as well as more abundant cartilage matrix. Morphometric analysis revealed that Meckel's cartilage lacunae were smaller in the fetuses from the experimental group, although not showing any remarkable alteration in shape. The results suggested that inhalation of cigarette smoke by pregnant rats during the organogenic period induced growth retardation and delayed cellular differentiation in rat fetal Meckel's cartilage. PMID:16113936

  7. Tibolone inhibits bone resorption without secondary positive effects on cartilage degradation

    Directory of Open Access Journals (Sweden)

    Byrjalsen I

    2008-11-01

    Full Text Available Abstract Background Osteoarthritis is associated with increased bone resorption and increased cartilage degradation in the subchondral bone and joint. The objective of the present study was to determine whether Tibolone, a synthetic steroid with estrogenic, androgenic, and progestogenic properties, would have similar dual actions on both bone and cartilage turnover, as reported previously with some SERMS and HRT. Methods This study was a secondary analysis of ninety-one healthy postmenopausal women aged 52–75 yrs entered a 2-yr double blind, randomized, placebo-controlled study of treatment with either 1.25 mg/day (n = 36, or 2.5 mg/day Tibolone (n = 35, or placebo (n = 20, (J Clin Endocrinol Metab. 1996 Jul;81(7:2419–22 Second void morning urine samples were collected at baseline, and at 3, 6, 12, and 24 months. Urine CrossLaps® ELISA (CTX-I and Urine CartiLaps® ELISA (CTX-II was investigated as markers of bone resorption and cartilage degradation, respectively. Results Tibolone significantly (P Conclusion These data suggest uncoupling of the bone and cartilage effects of the synthetic steroid, Tibolone. Bone resorption was significantly decreased, whereas cartilage degradation was unchanged. These effects are in contrast to those observed some SERMs with effects on both bone and cartilage degradation. These effects may in part be described by the complicated pharmacology of Tibolone on testosterone, estrogen and progesterone receptors.

  8. Electrospun Cartilage-Derived Matrix Scaffolds for Cartilage Tissue Engineering

    OpenAIRE

    Garrigues, N. William; Little, Dianne; Sanchez-Adams, Johannah; David S Ruch; Guilak, Farshid

    2014-01-01

    Macroscale scaffolds created from cartilage-derived matrix (CDM) demonstrate chondroinductive properties, but many fabrication methods do not allow for control of nanoscale architecture. In this regard, electrospun scaffolds have shown significant promise for cartilage tissue engineering. However, nanofibrous materials generally exhibit a relatively small pore size and require techniques such as multi-layering or the inclusion of sacrificial fibers to enhance cellular infiltration. The object...

  9. Engineered cartilage covered ear implants for auricular cartilage reconstruction.

    Science.gov (United States)

    Lee, Sang Jin; Broda, Christopher; Atala, Anthony; Yoo, James J

    2011-02-14

    Cartilage tissues are often required for auricular tissue reconstruction. Currently, alloplastic ear-shaped medical implants composed of silicon and polyethylene are being used clinically. However, the use of these implants is often associated with complications, including inflammation, infection, erosion, and dislodgement. To overcome these limitations, we propose a system in which tissue-engineered cartilage serves as a shell that entirely covers the alloplastic implants. This study investigated whether cartilage tissue, engineered with chondrocytes and a fibrin hydrogel, would provide adequate coverage of a commercially used medical implant. To demonstrate the in vivo stability of cell-fibrin constructs, we tested variations of fibrinogen and thrombin concentration as well as cell density. After implantation, the retrieved engineered cartilage tissue was evaluated by histo- and immunohistochemical, biochemical, and mechanical analyses. Histomorphological evaluations consistently showed cartilage formation over the medical implants with the maintenance of dimensional stability. An initial cell density was determined that is critical for the production of matrix components such as glycosaminoglycans (GAG), elastin, type II collagen, and for mechanical strength. This study shows that engineered cartilage tissues are able to serve as a shell that entirely covers the medical implant, which may minimize the morbidity associated with implant dislodgement. PMID:21182236

  10. Delayed gadolinium-enhanced MRI of cartilage (dGEMRIC) and morphologic MRI of cartilage in the long-term follow-up after Legg–Calvé–Perthes disease (LCPD)

    International Nuclear Information System (INIS)

    The purpose of the present study was to evaluate the feasibility of delayed gadolinium-enhanced magnetic resonance imaging of cartilage (dGEMRIC) in the detection of cartilage changes versus morphologic imaging in the long-term course of Legg–Calvé–Perthes disease (LCPD). A total of 31 hips in 26 patients (mean age, 30.0 years; range, 18–54 years) who were diagnosed with LCPD in childhood were included. Twenty-one radiographically normal contralateral hips served as controls. dGEMRIC indices of femoral and acetabular cartilage in the weight-bearing zone. Cartilage morphology was classified on radial PD-weighted images according to the modified Outerbridge classification. Mean dGEMRIC values of cartilage were significantly lower in hips after LCPD than in the radiographically normal contralateral hips (513 ± 100 ms vs. 579 ± 103 ms; P = 0.026). In 24 out of 31 LCPD hips and in 4 out of 21 radiographically normal contralateral hips, morphological cartilage changes were noted. Analysis of variance analysis revealed a significant influence of Outerbridge grading on decreased T1-values (P = 0.031). Our results suggest that dGEMRIC at 1.5 T is suitable to assess cartilage quality changes in the long-term follow-up after LCPD. The evaluation of biochemical cartilage quality with dGEMRIC may provide additional information about early cartilage changes occurring without visible alterations of cartilage morphology.

  11. The interpretation of results of protein turnover studies

    International Nuclear Information System (INIS)

    This interpretation of the protein turnover studies is made on the basis of modern knowledge of protein synthesis. A theory has been developed which gives a simple interpretation of protein turnover data. As, apparently, no disturbances leading to an endogenous hyper catabolism or hypo catabolism exist, altered protein turnover results with labelled albumin can only be interpreted as follows. Increased loss of protein takes place in the renal system or the intestinal tract. A decreased pool of building blocks are caused by gastro-intestinal diseases or hunger. Finally disturbances in the liver are caused by an acquired liver disease. 2 tabs

  12. Determining Tension-Compression Nonlinear Mechanical Properties of Articular Cartilage from Indentation Testing.

    Science.gov (United States)

    Chen, Xingyu; Zhou, Yilu; Wang, Liyun; Santare, Michael H; Wan, Leo Q; Lu, X Lucas

    2016-04-01

    The indentation test is widely used to determine the in situ biomechanical properties of articular cartilage. The mechanical parameters estimated from the test depend on the constitutive model adopted to analyze the data. Similar to most connective tissues, the solid matrix of cartilage displays different mechanical properties under tension and compression, termed tension-compression nonlinearity (TCN). In this study, cartilage was modeled as a porous elastic material with either a conewise linear elastic matrix with cubic symmetry or a solid matrix reinforced by a continuous fiber distribution. Both models are commonly used to describe the TCN of cartilage. The roles of each mechanical property in determining the indentation response of cartilage were identified by finite element simulation. Under constant loading, the equilibrium deformation of cartilage is mainly dependent on the compressive modulus, while the initial transient creep behavior is largely regulated by the tensile stiffness. More importantly, altering the permeability does not change the shape of the indentation creep curves, but introduces a parallel shift along the horizontal direction on a logarithmic time scale. Based on these findings, a highly efficient curve-fitting algorithm was designed, which can uniquely determine the three major mechanical properties of cartilage (compressive modulus, tensile modulus, and permeability) from a single indentation test. The new technique was tested on adult bovine knee cartilage and compared with results from the classic biphasic linear elastic curve-fitting program. PMID:26240062

  13. Does increased local bone resorption secondary to breast and prostate cancer result in increased cartilage degradation?

    DEFF Research Database (Denmark)

    Leeming, Diana J; Byrjalsen, Inger; Qvist, Per;

    2008-01-01

    BACKGROUND: Breast and prostate cancer patients often develop lesions of locally high bone turnover, when the primary tumor metastasizes to the bone causing an abnormal high bone resorption at this site. The objective of the present study was to determine whether local increased bone turnover in...... breast and prostate cancer patients is associated with an increase in cartilage degradation and to test in vitro whether osteoclasts or cathepsin K alone generate CTXII from human bone. METHODS: The study included 132 breast and prostate cancer patient, where presence of bone metastases was graded...... according to the Soloway score. Total bone resorption (CTXItotal) and cartilage degradation (CTXII) were determined. RESULTS: Breast and prostate cancer patients with bone metastases revealed significant increased levels of CTXItotal at Soloway scores 1 and higher compared to patients without bone...

  14. Protein turnover in sheep

    International Nuclear Information System (INIS)

    Considerable advances have been made in the knowledge of the mechanisms and control of synthesis and degradation of proteins in animal tissues during the last decade. Most of the work on the measurement of synthetic and degradative rates of the mixed protein fraction from tissues has been conducted in the rat. There have, unfortunately, been few publications describing results of protein turnover studies with ruminants. Consideration is given here to the techniques used to measure protein turnover, and some of the results obtained, particularly with sheep, are summarized. No attempt has been made to discuss directly the situation in parasitized animals; rather the aim is to provide background information which complements other work dealing with the effects of parasites on the nitrogen metabolism of ruminants. (author)

  15. Cellular responses of embryonic hyaline cartilage to experimental wounding in vitro.

    Science.gov (United States)

    Walker, E A; Verner, A; Flannery, C R; Archer, C W

    2000-01-01

    It is well established that the reparative potential of many tissues is greatest during embryonic development. Despite the extensive literature documenting repair in nonembryonic cartilage models, there is no comparable wealth of experience relating to embryonic cartilage repair. With the embryonic chick sternum as a model of hyaline cartilage, this paper accounts cellular responses and alterations in extracellular matrix composition in response to experimental wounding in vitro. Creation of an experimental lesion induced a rapid (apoptosis and the expression of alpha5 and alpha6 integrin subunits. PMID:10716275

  16. MR imaging of cartilage repair procedures

    International Nuclear Information System (INIS)

    It is becoming increasingly important for the radiologist to evaluate the appearance and outcome of cartilage repair procedures. MR imaging is currently the best method for such evaluation but it is necessary to use cartilage-specific sequences and to modify those sequences when necessary to minimize artifacts from retained metal within the joint. This article reviews the surgical technique of the more commonly performed cartilage repair procedures, currently recommended techniques for the MR imaging evaluation of articular cartilage and cartilage repair procedures, and the MR imaging appearance of cartilage repair procedures and of the most frequently encountered complications following such procedures. (orig.)

  17. Glycoconjugate expression of chondrocytes and perichondrium during hyaline cartilage development in the rat.

    OpenAIRE

    Zschäbitz, A; Krahn, V; Gabius, H J; Weiser, H; Khaw, A; Biesalski, H. K.; Stofft, E

    1995-01-01

    Alterations in the expression of glycoconjugate structures during cartilage development in the chondrocranium, nasal skeleton, Meckel's cartilage, limb buds, vertebral bodies and ribs were investigated comparatively in 13 to 21-d-old rat embryos. The binding patterns of 24 biotinylated lectins were analysed in serial sections and compared with results obtained using histochemical methods. Proteoglycan distribution, assessed by conventional staining procedures, was not associated with lectin b...

  18. Voluntary turnover, volatility in voluntary turnover, and labor productivity.

    OpenAIRE

    Van Beveren, Ilke; Vanormelingen, Stijn; De Winne, Sophie; Sels, Luc

    2012-01-01

    Voluntary turnover is a frequently studied employee outcome in articles on the relationship between HRM and firm performance. The main assumption underlying these articles is “less voluntary turnover is better”. Recent research questioned this assumption and showed that the relationship between turnover and firm performance might be more complex than assumed thus far in strategic HRM literature. The purpose of this article is to add to the discussion and unravel this complex relationship. Bas...

  19. Biological evaluation of nutraceuticals affecting cartilage metabolism and inflammation

    OpenAIRE

    Hartog, A.

    2010-01-01

    Osteoarthritis is the most common joint disease and an important cause of physical disability. Clinical symptoms are frequently associated with a significant functional impairment and signs and symptoms of inflammation, including pain, stiffness and loss of mobility. In osteoarthritis the balance between cartilage synthesis and degradation is disturbed as a result of an altered mainly autocrine exposure of the chondrocytes to various cytokines and growth factors. RA is a chronic, inflammatory...

  20. Transcriptomic profiling of cartilage ageing.

    Science.gov (United States)

    Peffers, Mandy Jayne; Liu, Xuan; Clegg, Peter David

    2014-12-01

    The musculoskeletal system is severely affected by the ageing process, with many tissues undergoing changes that lead to loss of function and frailty. Articular cartilage is susceptible to age related diseases, such as osteoarthritis. Applying RNA-Seq to young and old equine cartilage, we identified an over-representation of genes with reduced expression relating to extracellular matrix, degradative proteases, matrix synthetic enzymes, cytokines and growth factors in cartilage from older donors. Here we describe the contents and quality controls in detail for the gene expression and related results published by Peffers and colleagues in Arthritis Research and Therapy 2013 associated with the data uploaded to ArrayExpress (E-MTAB-1386). PMID:26484061

  1. Transcriptomic profiling of cartilage ageing

    Directory of Open Access Journals (Sweden)

    Mandy Jayne Peffers

    2014-12-01

    Full Text Available The musculoskeletal system is severely affected by the ageing process, with many tissues undergoing changes that lead to loss of function and frailty. Articular cartilage is susceptible to age related diseases, such as osteoarthritis. Applying RNA-Seq to young and old equine cartilage, we identified an over-representation of genes with reduced expression relating to extracellular matrix, degradative proteases, matrix synthetic enzymes, cytokines and growth factors in cartilage from older donors. Here we describe the contents and quality controls in detail for the gene expression and related results published by Peffers and colleagues in Arthritis Research and Therapy 2013 associated with the data uploaded to ArrayExpress (E-MTAB-1386.

  2. CEO Turnover in Reverse Splits

    OpenAIRE

    Li-Hsun Wang; Chu-Hsiung Lin; Hsien-Ming Chen

    2010-01-01

    This study examines the application of CEO turnover on reverse stock splits firms. Using Taiwanese samples, we find that non-CEO turnover firms receive negative long-term abnormal returns, and their financial performances continue to decline following reverse splits. These findings are consistent with prior studies. Contrarily, neither significantly negative long-term abnormal returns nor changes on financial performance were found for CEO turnover firms. This study concludes that applying CE...

  3. PHOTOCROSSLINKABLE HYDROGELS FOR CARTILAGE TISSUE ENGINEERING

    NARCIS (Netherlands)

    Levett, Peter Andrew

    2015-01-01

    For millions of people, damaged cartilage is a major source of pain and disability. As those people often discover upon seeking medical treatment, once damaged, cartilage is very difficult to repair. Finding better clinical therapies for damaged cartilage has generated a huge amount of research inte

  4. Isolation, identification, and comparison of cartilage stem progenitor/cells from auricular cartilage and perichondrium

    OpenAIRE

    Xue, Ke; Zhang, Xiaodie; Qi, Lin; Zhou, Jia; Liu, Kai

    2016-01-01

    Auricular cartilage loss or defect remains a challenge to plastic surgeons, and cartilage regenerative medicine provides a novel method to solve the problem. However, ideal seeding cells seem to be the key point in the development of cartilage regeneration. Although bone marrow-mesenchymal stem cells were considered as the ideal seeding cells in cartilage regeneration, regenerative cartilage differentiated from bone marrow-mesenchymal stem cells still faces some problems. It is reported that ...

  5. MRI EVALUATION OF KNEE CARTILAGE

    Science.gov (United States)

    Rodrigues, Marcelo Bordalo; Camanho, Gilberto Luís

    2015-01-01

    Through the ability of magnetic resonance imaging (MRI) to characterize soft tissue noninvasively, it has become an excellent method for evaluating cartilage. The development of new and faster methods allowed increased resolution and contrast in evaluating chondral structure, with greater diagnostic accuracy. In addition, physiological techniques for cartilage assessment that can detect early changes before the appearance of cracks and erosion have been developed. In this updating article, the various techniques for chondral assessment using knee MRI will be discussed and demonstrated. PMID:27022562

  6. Enzymatic digestion of articular cartilage results in viscoelasticity changes that are consistent with polymer dynamics mechanisms

    Directory of Open Access Journals (Sweden)

    June Ronald K

    2009-11-01

    Full Text Available Abstract Background Cartilage degeneration via osteoarthritis affects millions of elderly people worldwide, yet the specific contributions of matrix biopolymers toward cartilage viscoelastic properties remain unknown despite 30 years of research. Polymer dynamics theory may enable such an understanding, and predicts that cartilage stress-relaxation will proceed faster when the average polymer length is shortened. Methods This study tested whether the predictions of polymer dynamics were consistent with changes in cartilage mechanics caused by enzymatic digestion of specific cartilage extracellular matrix molecules. Bovine calf cartilage explants were cultured overnight before being immersed in type IV collagenase, bacterial hyaluronidase, or control solutions. Stress-relaxation and cyclical loading tests were performed after 0, 1, and 2 days of incubation. Results Stress-relaxation proceeded faster following enzymatic digestion by collagenase and bacterial hyaluronidase after 1 day of incubation (both p ≤ 0.01. The storage and loss moduli at frequencies of 1 Hz and above were smaller after 1 day of digestion by collagenase and bacterial hyaluronidase (all p ≤ 0.02. Conclusion These results demonstrate that enzymatic digestion alters cartilage viscoelastic properties in a manner consistent with polymer dynamics mechanisms. Future studies may expand the use of polymer dynamics as a microstructural model for understanding the contributions of specific matrix molecules toward tissue-level viscoelastic properties.

  7. T2* mapping for articular cartilage assessment: principles, current applications, and future prospects

    International Nuclear Information System (INIS)

    With advances in joint preservation surgery that are intended to alter the course of osteoarthritis by early intervention, accurate and reliable assessment of the cartilage status is critical. Biochemically sensitive MRI techniques can add robust biomarkers for disease onset and progression, and therefore, could be meaningful assessment tools for the diagnosis and follow-up of cartilage abnormalities. T2* mapping could be a good alternative because it would combine the benefits of biochemical cartilage evaluation with remarkable features including short imaging time and the ability of high-resolution three-dimensional cartilage evaluation - without the need for contrast media administration or special hardware. Several in vitro and in vivo studies, which have elaborated on the potential of cartilage T2* assessment in various cartilage disease patterns and grades of degeneration, have been reported. However, much remains to be understood and certain unresolved questions have become apparent with these studies that are crucial to the further application of this technique. This review summarizes the principles of the technique and current applications of T2* mapping for articular cartilage assessment. Limitations of recent studies are discussed and the potential implications for patient care are presented. (orig.)

  8. Three dimensional patient-specific collagen architecture modulates cartilage responses in the knee joint during gait.

    Science.gov (United States)

    Räsänen, Lasse P; Mononen, Mika E; Lammentausta, Eveliina; Nieminen, Miika T; Jurvelin, Jukka S; Korhonen, Rami K

    2016-08-01

    Site-specific variation of collagen fibril orientations can affect cartilage stresses in knee joints. However, this has not been confirmed by 3-D analyses. Therefore, we present a novel method for evaluation of the effect of patient-specific collagen architecture on time-dependent mechanical responses of knee joint cartilage during gait. 3-D finite element (FE) models of a human knee joint were created with the collagen architectures obtained from T2 mapped MRI (patient-specific model) and from literature (literature model). The effect of accuracy of the implementation of collagen fibril architecture into the model was examined by using a submodel with denser FE mesh. Compared to the literature model, fibril strains and maximum principal stresses were reduced especially in the superficial/middle regions of medial tibial cartilage in the patient-specific model after the loading response of gait (up to -413 and -26%, respectively). Compared to the more coarsely meshed joint model, the patient-specific submodel demonstrated similar strain and stress distributions but increased values particularly in the superficial cartilage regions (especially stresses increased >60%). The results demonstrate that implementation of subject-specific collagen architecture of cartilage in 3-D modulates location- and time-dependent mechanical responses of human knee joint cartilage. Submodeling with more accurate implementation of collagen fibril architecture alters cartilage stresses particularly in the superficial/middle tissue. PMID:26714834

  9. T2* mapping for articular cartilage assessment: principles, current applications, and future prospects

    Energy Technology Data Exchange (ETDEWEB)

    Hesper, Tobias; Bittersohl, Daniela; Krauspe, Ruediger; Zilkens, Christoph [University Duesseldorf, Department of Orthopaedics Medical Faculty, Duesseldorf (Germany); Hosalkar, Harish S. [Center of Hip Preservation and Children' s Orthopaedics, San Diego, CA (United States); Welsch, Goetz H. [Medical University of Vienna, MR Center, Department of Radiology, Vienna (Austria); Bittersohl, Bernd [University Duesseldorf, Department of Orthopaedics Medical Faculty, Duesseldorf (Germany); Heinrich-Heine University, Medical School, Department of Orthopaedics, Duesseldorf (Germany)

    2014-10-15

    With advances in joint preservation surgery that are intended to alter the course of osteoarthritis by early intervention, accurate and reliable assessment of the cartilage status is critical. Biochemically sensitive MRI techniques can add robust biomarkers for disease onset and progression, and therefore, could be meaningful assessment tools for the diagnosis and follow-up of cartilage abnormalities. T2* mapping could be a good alternative because it would combine the benefits of biochemical cartilage evaluation with remarkable features including short imaging time and the ability of high-resolution three-dimensional cartilage evaluation - without the need for contrast media administration or special hardware. Several in vitro and in vivo studies, which have elaborated on the potential of cartilage T2* assessment in various cartilage disease patterns and grades of degeneration, have been reported. However, much remains to be understood and certain unresolved questions have become apparent with these studies that are crucial to the further application of this technique. This review summarizes the principles of the technique and current applications of T2* mapping for articular cartilage assessment. Limitations of recent studies are discussed and the potential implications for patient care are presented. (orig.)

  10. Integrating Turnover Reasons and Shocks with Turnover Decision Processes

    Science.gov (United States)

    Maertz, Carl P., Jr.; Kmitta, Kayla R.

    2012-01-01

    We interviewed and classified 186 quitters from many jobs and organizations via a theoretically-based protocol into five decision process types. We then tested exploratory hypotheses comparing users of these types on their propensity to report certain turnover reasons and turnover shocks. "Impulsive-type quitters," with neither a job offer in hand…

  11. Postnatal development of articular cartilage

    NARCIS (Netherlands)

    Turnhout, van M.C.

    2010-01-01

    Articular cartilage (AC) is the thin layer of tissue that covers the ends of the bones in the synovial joints in mammals. Functional adult AC has depth-dependent mechanical properties that are not yet present at birth. These depth-dependent mechanical properties in adult life are the result of a dep

  12. Compositional and structural studies of the bone-cartilage interface using PIXE and SAXS techniques

    International Nuclear Information System (INIS)

    Micro-proton-induced X-ray emission (μ-PIXE) analysis has been employed in investigating the presence of number of essential anions and cations in thin sections of diseased human articular cartilage affected by osteoarthritis (OA). Distribution maps for Ca, P, K and S in diseased sections show marked alterations in the concentrations of these at the bone-cartilage interface compared to normal tissue. For a decalcified section of human articular cartilage, organisational changes of the collagen network were investigated by small-angle X-ray scattering (SAXS). The established gradual reorientation of collagen fibres from vertical to the surface of the joint to normal to the bone-cartilage interface is observed to be heavily disrupted in OA.

  13. Compositional and structural studies of the bone-cartilage interface using PIXE and SAXS techniques

    Science.gov (United States)

    Kaabar, W.; laklouk, A.; Bunk, O.; Baily, M.; Farquharson, M. J.; Bradley, David

    2010-07-01

    Micro-proton-induced X-ray emission (μ-PIXE) analysis has been employed in investigating the presence of number of essential anions and cations in thin sections of diseased human articular cartilage affected by osteoarthritis (OA). Distribution maps for Ca, P, K and S in diseased sections show marked alterations in the concentrations of these at the bone-cartilage interface compared to normal tissue. For a decalcified section of human articular cartilage, organisational changes of the collagen network were investigated by small-angle X-ray scattering (SAXS). The established gradual reorientation of collagen fibres from vertical to the surface of the joint to normal to the bone-cartilage interface is observed to be heavily disrupted in OA.

  14. Compositional and structural studies of the bone-cartilage interface using PIXE and SAXS techniques

    Energy Technology Data Exchange (ETDEWEB)

    Kaabar, W., E-mail: W.kaabar@surrey.ac.u [Department of Physics, University of Surrey, Guildford, GU2 7XH (United Kingdom); Laklouk, A. [Al-Fateh University, Tripoli-Libya (Libyan Arab Jamahiriya); Bunk, O. [Swiss Light Source, Paul Scherrer Institute, 5232 Villigen (Switzerland); Baily, M. [Department of Medical Physics and Applied Radiation Sciences, McMaster University, 1280 Main Street West, Hamilton, Ontario, Canada, L8S 4K1 (Canada); Farquharson, M.J. [Surrey Ion Beam Centre, University of Surrey, Guildford, GU2 7XH (United Kingdom); Bradley, David [Department of Physics, University of Surrey, Guildford, GU2 7XH (United Kingdom)

    2010-07-21

    Micro-proton-induced X-ray emission ({mu}-PIXE) analysis has been employed in investigating the presence of number of essential anions and cations in thin sections of diseased human articular cartilage affected by osteoarthritis (OA). Distribution maps for Ca, P, K and S in diseased sections show marked alterations in the concentrations of these at the bone-cartilage interface compared to normal tissue. For a decalcified section of human articular cartilage, organisational changes of the collagen network were investigated by small-angle X-ray scattering (SAXS). The established gradual reorientation of collagen fibres from vertical to the surface of the joint to normal to the bone-cartilage interface is observed to be heavily disrupted in OA.

  15. Commitment Profiles and Employee Turnover

    Science.gov (United States)

    Stanley, Laura; Vandenberghe, Christian; Vandenberg, Robert; Bentein, Kathleen

    2013-01-01

    We examined how affective (AC), normative (NC), perceived sacrifice (PS), and few alternatives (FA) commitments combine to form profiles and determine turnover intention and turnover. We theorized that three mechanisms account for how profiles operate, i.e., the degree to which membership is internally regulated, the perceived desirability and…

  16. Occupational stress and employee turnover.

    Science.gov (United States)

    Bridger, Robert S; Day, Andrea J; Morton, Kate

    2013-01-01

    Questionnaire data captured in January-March 2007 were examined in relation to turnover in males and females during the next five years. In general, most of the workplace stressors (such as role conflict or peer support) were not antecedents of turnover in any group. Junior personnel with psychological strain in 2007 had an increased risk of turnover in the next five years. Low commitment to the service in 2007 increased the odds of turnover in male and female juniors and in female officers. Female juniors with less effective skills for coping with stress and who exercised less frequently on a weekly basis were more likely to leave. An incidental finding was that the odds of turnover were three times greater in female officers with children than in female officers with no children. Stress management interventions focusing on effective coping and sports and exercise participation which are targeted appropriately may improve retention. PMID:24047248

  17. How Employee Turnover Affects Productivity

    DEFF Research Database (Denmark)

    Eriksen, Bo

    Research on employee turnover suggests that turnover results in negative organization-level outcomes. This paper provides a firm-level analysis of the impact of the in- and outflows of human resources on productivity and how the presence of organizational slack resources moderates the effects of...... employee turnover. Drawing on a unique longitudinal dataset of 2,926 Danish manufacturing firms that combine individual-level data with firm-level data, the paper shows that job turnover has a substantial negative effect on total productivity but that the firm’s size, its capital intensity, and its age...... moderate this effect so that the negative consequences of employee turnover are less severe for larger, older and capital intensive firms. These moderating variables indicate the presence of slack resources in the firm, and thus that the accumulation of slack reduces the efficiency losses from employee...

  18. Cartilage-selective genes identified in genome-scale analysis of non-cartilage and cartilage gene expression

    Directory of Open Access Journals (Sweden)

    Cohn Zachary A

    2007-06-01

    Full Text Available Abstract Background Cartilage plays a fundamental role in the development of the human skeleton. Early in embryogenesis, mesenchymal cells condense and differentiate into chondrocytes to shape the early skeleton. Subsequently, the cartilage anlagen differentiate to form the growth plates, which are responsible for linear bone growth, and the articular chondrocytes, which facilitate joint function. However, despite the multiplicity of roles of cartilage during human fetal life, surprisingly little is known about its transcriptome. To address this, a whole genome microarray expression profile was generated using RNA isolated from 18–22 week human distal femur fetal cartilage and compared with a database of control normal human tissues aggregated at UCLA, termed Celsius. Results 161 cartilage-selective genes were identified, defined as genes significantly expressed in cartilage with low expression and little variation across a panel of 34 non-cartilage tissues. Among these 161 genes were cartilage-specific genes such as cartilage collagen genes and 25 genes which have been associated with skeletal phenotypes in humans and/or mice. Many of the other cartilage-selective genes do not have established roles in cartilage or are novel, unannotated genes. Quantitative RT-PCR confirmed the unique pattern of gene expression observed by microarray analysis. Conclusion Defining the gene expression pattern for cartilage has identified new genes that may contribute to human skeletogenesis as well as provided further candidate genes for skeletal dysplasias. The data suggest that fetal cartilage is a complex and transcriptionally active tissue and demonstrate that the set of genes selectively expressed in the tissue has been greatly underestimated.

  19. Meta-analysis of the turnover of intestinal epithelia in preclinical animal species and humans.

    Science.gov (United States)

    Darwich, Adam S; Aslam, Umair; Ashcroft, Darren M; Rostami-Hodjegan, Amin

    2014-12-01

    Due to the rapid turnover of the small intestinal epithelia, the rate at which enterocyte renewal occurs plays an important role in determining the level of drug-metabolizing enzymes in the gut wall. Current physiologically based pharmacokinetic (PBPK) models consider enzyme and enterocyte recovery as a lumped first-order rate. An assessment of enterocyte turnover would enable enzyme and enterocyte renewal to be modeled more mechanistically. A literature review together with statistical analysis was employed to establish enterocyte turnover in human and preclinical species. A total of 85 studies was identified reporting enterocyte turnover in 1602 subjects in six species. In mice, the geometric weighted combined mean (WX) enterocyte turnover was 2.81 ± 1.14 days (n = 169). In rats, the weighted arithmetic mean enterocyte turnover was determined to be 2.37 days (n = 501). Humans exhibited a geometric WX enterocyte turnover of 3.48 ± 1.55 days for the gastrointestinal epithelia (n = 265), displaying comparable turnover to that of cytochrome P450 enzymes in vitro (0.96-4.33 days). Statistical analysis indicated humans to display longer enterocyte turnover as compared with preclinical species. Extracted data were too sparse to support regional differences in small intestinal enterocyte turnover in humans despite being indicated in mice. The utilization of enterocyte turnover data, together with in vitro enzyme turnover in PBPK modeling, may improve the predictions of metabolic drug-drug interactions dependent on enzyme turnover (e.g., mechanism-based inhibition and enzyme induction) as well as absorption of nanoparticle delivery systems and intestinal metabolism in special populations exhibiting altered enterocyte turnover. PMID:25233858

  20. Development of artificial articular cartilage.

    Science.gov (United States)

    Oka, M; Ushio, K; Kumar, P; Ikeuchi, K; Hyon, S H; Nakamura, T; Fujita, H

    2000-01-01

    Attempts have been made to develop an artificial articular cartilage on the basis of a new viewpoint of joint biomechanics in which the lubrication and load-bearing mechanisms of natural and artificial joints are compared. Polyvinyl alcohol hydrogel (PVA-H), 'a rubber-like gel', was investigated as an artificial articular cartilage and the mechanical properties of this gel were improved through a new synthetic process. In this article the biocompatibility and various mechanical properties of the new improved PVA-H is reported from the perspective of its usefulness as an artificial articular cartilage. As regards lubrication, the changes in thickness and fluid pressure of the gap formed between a glass plate and the specimen under loading were measured and it was found that PVA-H had a thicker fluid film under higher pressures than polyethylene (PE) did. The momentary stress transmitted through the specimen revealed that PVA-H had a lower peak stress and a longer duration of sustained stress than PE, suggesting a better damping effect. The wear factor of PVA-H was approximately five times that of PE. Histological studies of the articular cartilage and synovial membranes around PVA-H implanted for 8-52 weeks showed neither inflammation nor degenerative changes. The artificial articular cartilage made from PVA-H could be attached to the underlying bone using a composite osteochondral device made from titanium fibre mesh. In the second phase of this work, the damage to the tibial articular surface after replacement of the femoral surface in dogs was studied. Pairs of implants made of alumina, titanium or PVA-H on titanium fibre mesh were inserted into the femoral condyles. The two hard materials caused marked pathological changes in the articular cartilage and menisci, but the hydrogel composite replacement caused minimal damage. The composite osteochondral device became rapidly attached to host bone by ingrowth into the supporting mesh. The clinical implications of

  1. Influence of osteoarthritis grade on molecular signature of human cartilage.

    Science.gov (United States)

    Zhou, Shuanhu; Thornhill, Thomas S; Meng, Fangang; Xie, Li; Wright, John; Glowacki, Julie

    2016-03-01

    Articular chondrocytes maintain cartilage matrix turnover and have the capacity for anabolic and catabolic activities that can be influenced by injury and disease. This study tested the hypothesis that catabolic genes are upregulated with regional osteoarthritis (OA) disease severity within a joint. With IRB approval, specimens of knee cartilage obtained as discarded tissues from subjects undergoing arthroplasty were partitioned for each subject by OA disease severity and evaluated for gene expression by RT-PCR. There was regional OA grade-associated upregulation of expected inflammatory mediators TNF-α, TNF receptors, IFN-γ, and interleukins as well as genes encoding proteolytic enzymes, including Adamts-5 and MMPs. Osteoclast-related genes, cathepsin K, tartrate-resistant acid phosphatase (TRAP), RANKL, RANK, M-CSF, and c-fms, but not osteoprotegerin, were induced in advanced grades. In vitro treatment of normal human chondrocytes with interleukin-1β upregulated similar genes; this provides evidence that chondrocytes per se can be the source of osteoclast-related factors. Immunohistochemical staining showed that RANK- and RANKL-positive cells were abundant in advanced grades, especially in chondrocyte clusters. This suggests a possible autocrine mechanism by which an osteoclast phenotype is induced in articular chondrocytes. In sum, these studies identified gene expression signatures in human OA cartilage based upon regional disease severity within a joint. There was an effect of OA Grade on expression of osteoclastic lytic enzymes and regulatory factors in human articular chondrocytes. Induction of an osteoclast-like phenotype in chondrocytes may be part of OA progression and suggests specific therapeutic approaches. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:454-462, 2016. PMID:26336057

  2. Does increased local bone resorption secondary to breast and prostate cancer result in increased cartilage degradation?

    International Nuclear Information System (INIS)

    Breast and prostate cancer patients often develop lesions of locally high bone turnover, when the primary tumor metastasizes to the bone causing an abnormal high bone resorption at this site. The objective of the present study was to determine whether local increased bone turnover in breast and prostate cancer patients is associated with an increase in cartilage degradation and to test in vitro whether osteoclasts or cathepsin K alone generate CTXII from human bone. The study included 132 breast and prostate cancer patient, where presence of bone metastases was graded according to the Soloway score. Total bone resorption (CTXItotal) and cartilage degradation (CTXII) were determined. Breast and prostate cancer patients with bone metastases revealed significant increased levels of CTXItotal at Soloway scores 1 and higher compared to patients without bone metastases (p < 0.001). CTXII was statistically elevated at score 3 and 4 (p < 0.01). CTXII/CTXItotal significantly decreased at score 3 and 4 (p < 0.001). Levels of CTXItotal, CTXII and CTXII/CTXItotal changed +900%, +130%, and -90%, respectively at Soloway score 4 compared to score 0. The in vitro experiments revealed that osteoclasts released CTXI fragments but not CTXII from bone specimens. The same was observed for cathepsin K. Data suggest that an uncoupling between bone resorption and cartilage degradation occurs in breast and lung cancer patient

  3. How Employee Turnover Affects Productivity

    DEFF Research Database (Denmark)

    Eriksen, Bo

    employee turnover. Drawing on a unique longitudinal dataset of 2,926 Danish manufacturing firms that combine individual-level data with firm-level data, the paper shows that job turnover has a substantial negative effect on total productivity but that the firm’s size, its capital intensity, and its age...... moderate this effect so that the negative consequences of employee turnover are less severe for larger, older and capital intensive firms. These moderating variables indicate the presence of slack resources in the firm, and thus that the accumulation of slack reduces the efficiency losses from employee...

  4. The Executive Turnover Risk Premium

    OpenAIRE

    Peters, Florian S; Wagner, Alexander F

    2012-01-01

    Executive compensation has increased dramatically over the past 15 years, but so has forced CEO turnover. We argue that part of the development of CEO pay can be explained by the adverse consequences that forced turnover implies for a CEO. We ¯nd that for the CEOs of the largest US corporations, a one percentage point increase in exogenous turnover risk is associated with $40,000 to $90,000 more in terms of total compensation. The size of this risk premium is in line with estimates of the imp...

  5. Texture analysis of articular cartilage traumatic changes in the knee calculated from morphological 3.0 T MR imaging

    Energy Technology Data Exchange (ETDEWEB)

    Boutsikou, Konstantina [Department of Medical Radiologic Technology, Technological Educational Institute of Athens, Ag.Spyridonos, Egaleo, Athens 12210 (Greece); Kostopoulos, Spiros; Glotsos, Dimitris; Cavouras, Dionisis [Department of Medical Instruments Technology, Technological Educational Institute of Athens, Ag.Spyridonos, Egaleo, Athens 12210 (Greece); Lavdas, Eleftherios; Oikonomou, Georgia [Department of Medical Radiologic Technology, Technological Educational Institute of Athens, Ag.Spyridonos, Egaleo, Athens 12210 (Greece); Malizos, Konstantinos [Department of Orthopaedic Surgery, University of Thessaly, School of Health Sciences, University Hospital of Larissa, Biopolis, Larissa 41110 (Greece); Fezoulidis, Ioannis V. [Department of Radiology, University of Thessaly, School of Health Sciences, University Hospital of Larissa, Biopolis, Larissa 41110 (Greece); Vlychou, Marianna, E-mail: mvlychou@med.uth.gr [Department of Radiology, University of Thessaly, School of Health Sciences, University Hospital of Larissa, Biopolis, Larissa 41110 (Greece)

    2013-08-15

    Objectives: In the present work, we aim to identify changes in the cartilage texture of the injured knee in young, physically active, patients by computer analysis of MRI images based on 3.0 T morphological sequences. Methods: Fifty-three young patients with training injury or trauma in one knee underwent MRI and arthroscopy. Textural features were computed from the MRI images of the knee-cartilages and two classes were formed of 28 normal and 16 with pathology only in the medial femoral condyle (MFC) cartilage. Results: Textural features with statistically significant differences between the two classes were found only at the MFC and the medial tibial condyle (MTC) areas. Three features-combinations, at the MFC or the MTC, maximized the between classes separation, thus, rendering alterations in cartilage texture due to injury more evident. The MFC cartilage in the pathology class was found more inhomogeneous in the distribution of gray-levels and of lower texture anisotropy and the opposed MTC cartilage, though normal on MRI and arthroscopy, was found to have lower texture anisotropy than cartilage in the normal class. Conclusion: Texture analysis may be used as an adjunct to morphological MR imaging for improving the detection of subtle cartilage changes and contributes to early therapeutic approach.

  6. Texture analysis of articular cartilage traumatic changes in the knee calculated from morphological 3.0 T MR imaging

    International Nuclear Information System (INIS)

    Objectives: In the present work, we aim to identify changes in the cartilage texture of the injured knee in young, physically active, patients by computer analysis of MRI images based on 3.0 T morphological sequences. Methods: Fifty-three young patients with training injury or trauma in one knee underwent MRI and arthroscopy. Textural features were computed from the MRI images of the knee-cartilages and two classes were formed of 28 normal and 16 with pathology only in the medial femoral condyle (MFC) cartilage. Results: Textural features with statistically significant differences between the two classes were found only at the MFC and the medial tibial condyle (MTC) areas. Three features-combinations, at the MFC or the MTC, maximized the between classes separation, thus, rendering alterations in cartilage texture due to injury more evident. The MFC cartilage in the pathology class was found more inhomogeneous in the distribution of gray-levels and of lower texture anisotropy and the opposed MTC cartilage, though normal on MRI and arthroscopy, was found to have lower texture anisotropy than cartilage in the normal class. Conclusion: Texture analysis may be used as an adjunct to morphological MR imaging for improving the detection of subtle cartilage changes and contributes to early therapeutic approach

  7. Preclinical Studies for Cartilage Repair

    OpenAIRE

    Hurtig, Mark B.; Buschmann, Michael D; Fortier, Lisa A; Hoemann, Caroline D; Hunziker, Ernst B.; Jurvelin, Jukka S.; Mainil-Varlet, Pierre; McIlwraith, C. Wayne; Sah, Robert L.; Whiteside, Robert A.

    2011-01-01

    Investigational devices for articular cartilage repair or replacement are considered to be significant risk devices by regulatory bodies. Therefore animal models are needed to provide proof of efficacy and safety prior to clinical testing. The financial commitment and regulatory steps needed to bring a new technology to clinical use can be major obstacles, so the implementation of highly predictive animal models is a pressing issue. Until recently, a reductionist approach using acute chondral...

  8. Diode laser (980nm) cartilage reshaping

    Science.gov (United States)

    El Kharbotly, A.; El Tayeb, T.; Mostafa, Y.; Hesham, I.

    2011-03-01

    Loss of facial or ear cartilage due to trauma or surgery is a major challenge to the otolaryngologists and plastic surgeons as the complicated geometric contours are difficult to be animated. Diode laser (980 nm) has been proven effective in reshaping and maintaining the new geometric shape achieved by laser. This study focused on determining the optimum laser parameters needed for cartilage reshaping with a controlled water cooling system. Harvested animal cartilages were angulated with different degrees and irradiated with different diode laser powers (980nm, 4x8mm spot size). The cartilage specimens were maintained in a deformation angle for two hours after irradiation then released for another two hours. They were serially measured and photographed. High-power Diode laser irradiation with water cooling is a cheep and effective method for reshaping the cartilage needed for reconstruction of difficult situations in otorhinolaryngologic surgery. Key words: cartilage,diode laser (980nm), reshaping.

  9. Multimodal evaluation of tissue-engineered cartilage

    OpenAIRE

    Mansour, Joseph M.; Welter, Jean F.

    2013-01-01

    Tissue engineering (TE) has promise as a biological solution and a disease modifying treatment for arthritis. Although cartilage can be generated by TE, substantial inter- and intra-donor variability makes it impossible to guarantee optimal, reproducible results. TE cartilage must be able to perform the functions of native tissue, thus mechanical and biological properties approaching those of native cartilage are likely a pre-requisite for successful implantation. A quality-control assessment...

  10. Labour Turnover and Firm Performance

    OpenAIRE

    S. Brown; Garino, G.; C. Martin

    2007-01-01

    We explore the impact of labour turnover on firm performance by analysing the predictions of an extension of the efficiency wage model of Salop (1979) developed by Garino and Martin (2007), which separates incumbent and newly hired workers in the production function. Within this theoretical framework, an exogenous increase in the turnover rate can increase profits if firms do not choose wages unilaterally. We test the theoretical predictions of the model using UK cross-section establishment-l...

  11. Employment Turnover and Unemployment Insurance

    OpenAIRE

    Hassler, John; Vicente Rodríguez Mora, José

    1997-01-01

    Two features distinguish European and US labour markets. First, most European countries have a considerably more generous unemployment insurance system. Second, the duration of unemployment and employment spells are substantially higher in Europe – employment turnover is lower. We show that self-insurance, i.e. saving and borrowing, is a good substitute for unemployment insurance when turnover is as high as in the United States. If the insurance system is less than perfectly actuarially fair,...

  12. Macroscopical, Histological, and In Vitro Characterization of Nonosteoarthritic Versus Osteoarthritic Hip Joint Cartilage

    Science.gov (United States)

    Badendick, Jessica; Godkin, Owen; Kohl, Benjamin; Meier, Carola; Jagielski, Michal; Huang, Zhao; Arens, Stephan; Schneider, Tobias; Schulze-Tanzil, Gundula

    2016-01-01

    Osteoarthritis (OA) might affect chondrocyte culture characteristics and complement expression. Therefore, this study addressed the interrelation between macroscopical and microscopical structure, complement expression, and chondrocyte culture characteristics in non-OA and OA cartilage. Femoral head cartilage samples harvested from patients with femoral neck fractures (FNFs) and OA were analyzed for macroscopical alterations using an in-house scoring system, graded histologically (Mankin score), and immunolabeled for complement regulatory proteins (CRPs) and receptors. Morphology of monolayer cultured chondrocytes isolated from a subset of samples was assessed. The macroscopical score distinguished the FNF and OA cartilage samples and correlated significantly with the histological results. Chondrocyte phenotype from FNF or OA cartilage differed. Complement receptor C5aR, CRPs CD55 and CD59, and weakly receptor C3AR were detected in the investigated FNF and OA cartilage, except for CD46, which was detected in only two of the five investigated donors. The in-house score also allows inexperienced observers to distinguish non-OA and OA cartilage for experimental purposes. PMID:27158224

  13. Predicting knee cartilage loss using adaptive partitioning of cartilage thickness maps

    DEFF Research Database (Denmark)

    Jørgensen, Dan R.; Dam, Erik B.; Lillholm, Martin

    2013-01-01

    This study investigates whether measures of knee cartilage thickness can predict future loss of knee cartilage. A slow and a rapid progressor group was determined using longitudinal data, and anatomically aligned cartilage thickness maps were extracted from MRI at baseline. A novel machine learni...

  14. Advances in treatment of articular cartilage injuries

    Directory of Open Access Journals (Sweden)

    Yuan-cheng LI

    2013-05-01

    Full Text Available Cartilage is a kind of terminally differentiated tissue devoid of vessel or nerve, and it is difficult to repair by itself after damage. Many studies for the treatment of cartilage injuries were performed in recent years aiming at repair of the structure and restoration of its function for injured joint. This article reviews the traditional methods of treatment for cartilage injuries, such as joint lavage with the aid of arthroscope, abrasion chondroplasty, laser abrasion and chondroplasty, and drilling of the subchondral bone-marrow space. The research advances in treatment of articular cartilage injuries with tissue engineering were summarized.

  15. Multimodal evaluation of tissue-engineered cartilage.

    Science.gov (United States)

    Mansour, Joseph M; Welter, Jean F

    2013-02-01

    Tissue engineering (TE) has promise as a biological solution and a disease modifying treatment for arthritis. Although cartilage can be generated by TE, substantial inter- and intra-donor variability makes it impossible to guarantee optimal, reproducible results. TE cartilage must be able to perform the functions of native tissue, thus mechanical and biological properties approaching those of native cartilage are likely a pre-requisite for successful implantation. A quality-control assessment of these properties should be part of the implantation release criteria for TE cartilage. Release criteria should certify that selected tissue properties have reached certain target ranges, and should be predictive of the likelihood of success of an implant in vivo. Unfortunately, it is not currently known which properties are needed to establish release criteria, nor how close one has to be to the properties of native cartilage to achieve success. Achieving properties approaching those of native cartilage requires a clear understanding of the target properties and reproducible assessment methodology. Here, we review several main aspects of quality control as it applies to TE cartilage. This includes a look at known mechanical and biological properties of native cartilage, which should be the target in engineered tissues. We also present an overview of the state of the art of tissue assessment, focusing on native articular and TE cartilage. Finally, we review the arguments for developing and validating non-destructive testing methods for assessing TE products. PMID:23606823

  16. Business Ethics & Employee Turnover: CAFE Matrix

    OpenAIRE

    Sapovadia, Vrajlal; Patel, Sweta

    2013-01-01

    Abstract: Business ethics is in discussion for its importance universally, so is the employee turnover in business. Unethical practices are unwanted, so is the high employee turnover. Unethical practices and high employee turnover in business is ubiquitous. No consensus exists on defining ethics. Employee turnover is well defined, but there is no consensus on when employee turnover is disadvantageous for the company. The Golden Rule or ethic of reciprocity, a maxim states that either ...

  17. Immersed Turnovers In Hyperbolic 3-Orbifolds

    OpenAIRE

    Rafalski, Shawn

    2007-01-01

    We show that any immersion, which is not a covering of an embedded 2-orbifold, of a totally geodesic hyperbolic turnover in a complete orientable hyperbolic 3-orbifold is contained in a hyperbolic 3-suborbifold with totally geodesic boundary, called the "turnover core,'' whose volume is bounded from above by a function depending only on the area of the given turnover. Furthermore, we show that, for a given type of turnover, there are only finitely many possibilities for the turnover core. As ...

  18. Government Turnover : Concepts, Measures and Applications

    OpenAIRE

    Horowitz, S; Hoff, K.; Milanovic, B.

    2009-01-01

    While government turnover is often thought of as an adverse source of instability, it may also be viewed as a favourable source of competition and institution-building. To articulate and test such hypotheses, this article describes two main concepts of government turnover: leadership turnover, or change in rulers, and ideological turnover, or change in the rulers' ideology. Refinements involve the mode, outcome and timing of turnover. The article discusses measurement issues that arise when t...

  19. Development of cartilage conduction hearing aid

    Directory of Open Access Journals (Sweden)

    H. Hosoi

    2010-04-01

    Full Text Available Purpose: The potential demand for hearing aids is increasing in accordance with aging of populations in many developed countries. Because certain patients cannot use air conduction hearing aids, they usually use bone conduction hearing aids. However, bone does not transmit sound as efficiently as air, and bone conduction hearing aids require surgery (bone anchored hearing aid or great pressure to the skull. The first purpose of this study is to examine the efficacy of a new sound conduction pathway via the cartilage. The second purpose is to develop a hearing aid with a cartilage conduction transducer for patients who cannot use regular air conduction hearing aids.Design/methodology/approach: We examined the hearing ability of a patient with atresia of both external auditory meatuses via three kinds of conduction pathways (air, bone, and cartilage. After the best position for the cartilage conduction transducer was found, audiometric evaluation was performed for his left ear with an insertion earphone (air conduction, a bone conduction transducer, and a cartilage conduction transducer. Then we made a new hearing aid using cartilage conduction and got subjective data from the patients.Findings: The tragal cartilage was the best position for the cartilage conduction transducer. The patient’s mean hearing levels were 58.3 dBHL, 6.7 dBHL, and 3.3 dBHL for air conduction, bone conduction, and cartilage conduction respectively. The hearing ability of the patients obtained from the cartilage conduction hearing aid was comparable to those from the bone conduction hearing aid.Practical implications: Hearing levels using cartilage conduction are very similar to those via bone conduction. Cartilage conduction hearing aids may overcome the practical disadvantages of bone conduction hearing aids such as pain and the need for surgery.Originality/value: We have clarified the efficacy of the cartilage conduction pathway and developed a prototype ‘cartilage

  20. Elemental and structural studies at the bone-cartilage interface

    International Nuclear Information System (INIS)

    Micro-Proton Induced X-ray Emission (μ-PIXE) and Proton Induced Gamma-ray Emission (PIGE) techniques were employed in the investigation of trace and essential elements distribution in normal and diseased human femoral head sections affected by osteoarthritis (OA). PIGE was exploited in the determination of elements of low atomic number z15 viz Ca, Z, P and S were determined by PIXE. Accumulations of key elements in the bone and cartilage sections were observed, significant S and Na concentrations being found in the cartilage region particularly in normal tissues. Zn showed enhanced concentrations at the bone-cartilage interface. At a synchrotron facility, small angle X-ray scattering (SAXS) was utilized on a decalcified human femoral head section affected by OA, direct measurements being made of spatial alterations of collagen fibres. The SAXS results showed a slight decrease in the axial periodicity between normal collagen type I and that in diseased tissue in various sites, in contrast with the findings of others.

  1. Elemental and structural studies at the bone-cartilage interface

    Science.gov (United States)

    Kaabar, W.; Daar, E.; Bunk, O.; Farquharson, M. J.; Laklouk, A.; Bailey, M.; Jeynes, C.; Gundogdu, O.; Bradley, D. A.

    2011-10-01

    Micro-Proton Induced X-ray Emission (μ-PIXE) and Proton Induced Gamma-ray Emission (PIGE) techniques were employed in the investigation of trace and essential elements distribution in normal and diseased human femoral head sections affected by osteoarthritis (OA). PIGE was exploited in the determination of elements of low atomic number z15 viz Ca, Z, P and S were determined by PIXE. Accumulations of key elements in the bone and cartilage sections were observed, significant S and Na concentrations being found in the cartilage region particularly in normal tissues. Zn showed enhanced concentrations at the bone-cartilage interface. At a synchrotron facility, small angle X-ray scattering (SAXS) was utilized on a decalcified human femoral head section affected by OA, direct measurements being made of spatial alterations of collagen fibres. The SAXS results showed a slight decrease in the axial periodicity between normal collagen type I and that in diseased tissue in various sites, in contrast with the findings of others.

  2. Elemental and structural studies at the bone-cartilage interface

    Energy Technology Data Exchange (ETDEWEB)

    Kaabar, W., E-mail: w.kaabar@surrey.ac.uk [Department of Physics, University of Surrey, Guildford GU2 7XH (United Kingdom); Daar, E. [Department of Physics, University of Surrey, Guildford GU2 7XH (United Kingdom); Bunk, O. [Swiss Light Source, Paul Scherrer Institute, 5232 Villigen (Switzerland); Farquharson, M.J. [Department of Medical Physics and Applied Radiation Sciences, McMaster University, 1280 Main Street West, Hamilton, Ontario, L8S 4K1 (Canada); Laklouk, A. [Al-Fateh University, Tripoli (Libya); Bailey, M.; Jeynes, C. [Surrey Ion Beam Centre, University of Surrey, Guildford GU2 7XH (United Kingdom); Gundogdu, O. [Umuttepe Campus, University of Kocaeli, 41380 Kocaeli (Turkey); Bradley, D.A. [Department of Physics, University of Surrey, Guildford GU2 7XH (United Kingdom)

    2011-10-01

    Micro-Proton Induced X-ray Emission ({mu}-PIXE) and Proton Induced Gamma-ray Emission (PIGE) techniques were employed in the investigation of trace and essential elements distribution in normal and diseased human femoral head sections affected by osteoarthritis (OA). PIGE was exploited in the determination of elements of low atomic number z<15 such as Na and F whereas elements with z>15 viz Ca, Z, P and S were determined by PIXE. Accumulations of key elements in the bone and cartilage sections were observed, significant S and Na concentrations being found in the cartilage region particularly in normal tissues. Zn showed enhanced concentrations at the bone-cartilage interface. At a synchrotron facility, small angle X-ray scattering (SAXS) was utilized on a decalcified human femoral head section affected by OA, direct measurements being made of spatial alterations of collagen fibres. The SAXS results showed a slight decrease in the axial periodicity between normal collagen type I and that in diseased tissue in various sites, in contrast with the findings of others.

  3. The influence of collagen network integrity on the accumulation of gadolinium-based MR contrast agents in articular cartilage

    International Nuclear Information System (INIS)

    Delayed gadolinium-enhanced MR imaging of cartilage is used to quantify the proteoglycan loss in early osteoarthritis. It is assumed that T 1 after Gd-DTPA administration in the near equilibrium state reflects selective proteoglycan loss from cartilage. To investigate the influence of the collagen network integrity on contrast accumulation, the relaxation rates ΔR1 and ΔR2 were compared after Gd-DTPA administration in a well established model of osteoarthritis. Collagen or proteoglycan depletion was induced by the proteolytic enzymes papain and collagenase in healthy bovine patellar cartilage. Using a dedicated MRI sequence, T1 and T2 maps were simultaneously acquired before and 11 h after Gd-DTPA administration. Depth-dependent profiles of ΔR1 and ΔR2 were calculated in healthy, proteoglycan and collagen-depleted articular cartilage and the mean values of different cartilage layers were compared using the Mann-Whitney-U test. In superficial layers (1 mm) there was no significant difference (p > 0.05) in either ΔR1 or ΔR2 between proteoglycan-depleted (16.6 ± 1.2 s-1, 15.9 ± 1.0 s-1) and collagen-depleted articular cartilage (15.3 ± 0.9 s-1, 15.5 ± 0.9 s-1). In deep layers (3 mm) both parameters were significantly higher (p = 0.005, 0.03) in proteoglycan-depleted articular cartilage (12.3 ± 1.1 s-1, 9.8 ± 0.8 s-1) than in collagen-depleted articular cartilage (9.1 ± 1.1 s-1, 8.7 ± 0.7 s-1). Both proteoglycan loss and alterations in the collagen network influence the accumulation of Gd-DTPA in articular cartilage with significant differences between superficial and deep cartilage layers. (orig.)

  4. Animal experimental research on microstructural behavior on the hyaline arthroidal cartilage after immobilization and remobilization

    Science.gov (United States)

    Refior, H. J.

    1980-01-01

    The degeneration of the articular cartilage after a period of immobilization was investigated. The experiment was carried out by the immobilization of the knee joints of rabbits. Even after remobilization there was an increase in the alterations. These changes did not prove to be reversible.

  5. Anatomical study of nasal cartilage in buffalo (Bubalus bubulus

    Directory of Open Access Journals (Sweden)

    Mahdi Yeganehzad

    2011-07-01

    Full Text Available This study used ten heads of adult buffalo taken from slaughterhouse. After transferring the samples to the anatomy hall, a split was carefully created on skin of muzzle and the skin was slowly separated from muscles and hypodermal connective tissue. Place of connection of cartilages to bone, cartilages to each other and shape of the cartilages were specified. In buffalo, nose apex has two nostrils fixed by bone and cartilage. After identifying and separating the cartilages, it was found that nasal cartilages in buffalo consisted of: 1 septum nasal located between two nostrils and reinforces it from inside. 2 dorso-lateral nasal cartilage constituting dorsal and lateral parts of the nostril. 3 ventro-lateral nasal cartilage constituting ventral and lateral parts of the nostril. 4 lateral accessory cartilage constituting lateral and ventral parts of the nostril. 5 medial accessory nasal cartilage located at Alar fold and connected to ventro-lateral nasal cartilage.

  6. Human rheumatoid arthritis tissue production of IL-17A drives matrix and cartilage degradation: synergy with tumour necrosis factor-alpha, Oncostatin M and response to biologic therapies.

    LENUS (Irish Health Repository)

    Moran, Ellen M

    2009-01-01

    INTRODUCTION: The aim of this study was to examine IL-17A in patients, following anti-TNF-alpha therapy and the effect of IL-17A on matrix turnover and cartilage degradation. METHODS: IL-17A expression was examined by ELISA and immunohistology in the rheumatoid arthritis (RA) joints. RA whole synovial tissue explant (RA ST), primary synovial fibroblasts (RASFC), human cartilage and chondrocyte cultures were stimulated with IL-17A +\\/- TNF-alpha and Oncostatin M (OSM). Matrix metalloproteinase (MMP) and tissue inhibitor (TIMP-1) were assessed by ELISA and zymography. Cartilage proteoglycan release was assessed histologically by Safranin-O staining. Clinical parameters, IL-17A, MMP\\/TIMP were assessed in patients pre\\/post biologic therapy. RESULTS: IL-17A levels were higher in RA vs osteoarthritis (OA)\\/normal joints (P < 0.05). IL-17A up-regulated MMP-1, -2, -9, and -13 in RA ST, RASFC, cartilage and chondrocyte cultures (P < 0.05). In combination with TNF-alpha and OSM, IL-17A shifted the MMP:TIMP-1 ratio in favor of matrix degradation (all P < 0.05). Cartilage proteoglycan depletion in response to IL-17A was mild; however, in combination with TNF-alpha or OSM showed almost complete proteoglycan depletion. Serum IL-17A was detected in 28% of patients commencing biologic therapy. IL-17A negative patients demonstrated reductions post therapy in serum MMP1\\/TIMP4, MMP3\\/TIMP1 and MMP3\\/TIMP4 ratios and an increase in CS846 (all P < 0.05). No significant changes were observed in IL-17A positive patients. CONCLUSIONS: IL-17A is produced locally in the inflamed RA joint. IL-17A promotes matrix turnover and cartilage destruction, especially in the presence of other cytokines, mimicking the joint environment. IL-17A levels are modulated in vivo, following anti-TNF therapy, and may reflect changes in matrix turnover.

  7. Dynamics of Adipocyte Turnover in Humans

    Energy Technology Data Exchange (ETDEWEB)

    Spalding, K; Arner, E; Westermark, P; Bernard, S; Buchholz, B; Bergmann, O; Blomqvist, L; Hoffstedt, J; Naslund, E; Britton, T; Concha, H; Hassan, M; Ryden, M; Frisen, J; Arner, P

    2007-07-16

    Obesity is increasing in an epidemic fashion in most countries and constitutes a public health problem by enhancing the risk for cardiovascular disease and metabolic disorders such as type 2 diabetes. Owing to the increase in obesity, life expectancy may start to decrease in developed countries for the first time in recent history. The factors determining fat mass in adult humans are not fully understood, but increased lipid storage in already developed fat cells is thought to be most important. We show that adipocyte number is a major determinant for the fat mass in adults. However, the number of fat cells stays constant in adulthood in lean and obese and even under extreme conditions, indicating that the number of adipocytes is set during childhood and adolescence. To establish the dynamics within the stable population of adipocytes in adults, we have measured adipocyte turnover by analyzing the integration of {sup 14}C derived from nuclear bomb tests in genomic DNA. Approximately 10% of fat cells are renewed annually at all adult ages and levels of body mass index. Neither adipocyte death nor generation rate is altered in obesity, suggesting a tight regulation of fat cell number that is independent of metabolic profile in adulthood. The high turnover of adipocytes establishes a new therapeutic target for pharmacological intervention in obesity.

  8. Abnormal mandibular growth and the condylar cartilage.

    Science.gov (United States)

    Pirttiniemi, Pertti; Peltomäki, Timo; Müller, Lukas; Luder, Hans U

    2009-02-01

    Deviations in the growth of the mandibular condyle can affect both the functional occlusion and the aesthetic appearance of the face. The reasons for these growth deviations are numerous and often entail complex sequences of malfunction at the cellular level. The aim of this review is to summarize recent progress in the understanding of pathological alterations occurring during childhood and adolescence that affect the temporomandibular joint (TMJ) and, hence, result in disorders of mandibular growth. Pathological conditions taken into account are subdivided into (1) congenital malformations with associated growth disorders, (2) primary growth disorders, and (3) acquired diseases or trauma with associated growth disorders. Among the congenital malformations, hemifacial microsomia (HFM) appears to be the principal syndrome entailing severe growth disturbances, whereas growth abnormalities occurring in conjunction with other craniofacial dysplasias seem far less prominent than could be anticipated based on their often disfiguring nature. Hemimandibular hyperplasia and elongation undoubtedly constitute the most obscure conditions that are associated with prominent, often unilateral, abnormalities of condylar, and mandibular growth. Finally, disturbances of mandibular growth as a result of juvenile idiopathic arthritis (JIA) and condylar fractures seem to be direct consequences of inflammatory and/or mechanical damage to the condylar cartilage. PMID:19164410

  9. Knee Joint Kinematics during Walking Influences the Spatial Cartilage Thickness Distribution in the Knee

    OpenAIRE

    Koo, Seungbum; Rylander, Jonathan H.; Andriacchi, Thomas P.

    2011-01-01

    The regional adaptation of knee cartilage morphology to the kinematics of walking has been suggested as an important factor in the evaluation of the consequences of alteration in normal gait leading to osteoarthritis. The purpose of this study was to investigate the association of spatial cartilage thickness distributions of the femur and tibia in the knee to the knee kinematics during walking. Gait data and knee MR images were obtained from 17 healthy volunteers (age 33.2±9.8 years). Cartila...

  10. Anti-Angiogenesis and Anti-Tumor Effect of Shark Cartilage Extract

    Institute of Scientific and Technical Information of China (English)

    王锋; 王漪涛; 谢莉萍; 张荣庆

    2001-01-01

    The effect of shark cartilage extract (SCE), purified in this laboratory, on angiogenesis in chick chorioallantoic membrane (CAM), on the activity of collagenase IV and on human umbilical vein endothelial cell (ECV-304) proliferation and apoptosis was investigated in vitro. The results showed that SCE caused a decline in CAM blood vessels and significantly prevented collagenase-induced collagenolysis. Moreover, SCE produced a dose-dependent decline in ECV-304 proliferation and altered its normal cell cycle. These results suggest that the anti-angiogenesis and anti-tumor effects of shark cartilage may be due to inhibition of endothelial cells as well as collagenolysis.

  11. Cysts of the semilunar cartilage

    International Nuclear Information System (INIS)

    On the basis of the studies listed in the bibliography, this dissertation reports on the pathology, clinical symptoms and radiology of cysts of the semilunar cartilage. The author analyses 118 cases of his own, with special regard to the results of pneumo-arthrographic investigations carried through according to a special technique by Schaefer. In the course of this work, measurements of the meniscal base are for the first time used as radiological criteria indicating the presence of a cyst of the semilunar cartilage. Furthermore the well-known radiological signs of cysts, such as bone defects according to Albert and Keller, light central spot in the meniscal body, as well as Rauber's sign and horizontal rupture, are investigated as to the frequency of their incidence. For that purpose all the X-ray pictures were subjected to a further dose scrutiny. A list of all the 118 cases with their clinical and radiological data is found in the annex, together with the results of the operations and patho-anatomical investigations. (orig.)

  12. Imaging diagnosis of the articular cartilage disorders

    International Nuclear Information System (INIS)

    Objective: To evaluate the diagnosis and differential diagnosis among the chronic osteoarthritis, rheumatoid arthritis and other chronic cartilage lesions on the plain films and MR images. Methods: Eighty-nine cases, including 115 joints, underwent plain film and MRI examination, and enhanced MRI scan was performed on 32 of them, including 44 joints. MRI scan sequences consisted of T1WI, T2WI + PDWI, STIR, and 3D FS SPGR. There were 90 knee joints in this group and each of the articular cartilage was divided into four parts: patella, femoral medial condyle, femoral lateral condyle, and tibia facet on MR images. The cartilage disorders were classified according to the outerbridge method. In addition, 61 cases including 75 joints were observed as a control group on the plain films and MR images. Results: 115 cartilage lesions were found on MR images, in which thinness of the cartilage (58 cases, 50.4%), bone changes under the cartilage (22 cases, 19.7%), medullar edema (22 cases, 19.7%), and synovial hyperplasia (52 cases, 45.2%) were seen. The patella cartilage was the most likely affected part (81/90, 90%). So the patellar cartilage lesions were divided as group 1 (grade I-II) and group 2 (grade III-IV) on MR images, which were compared with the plain film signs. The narrowing of the joint space and saccules under the articular surface were statistically significant with each other, and χ2 values were 9.349 and 9.885, respectively (P=0.002). Conclusion: No constant signs could be seen on the plain films with grade I-II cartilage disorders. While the narrowing joint space and saccules under the joint surface could be seen on them with grade III-IV cartilage disorders, which were mainly correlated with the cartilage disorders and bone changes under the articular cartilages. A combination of the plain films and MR images is the best imaging method for examining the joints and joint cartilages. Enhanced MRI scan is very helpful on the diagnosis and differential

  13. IL-1ß and BMPs - Interactive players of cartilage matrix degradation and regeneration

    Directory of Open Access Journals (Sweden)

    T Aigner

    2006-10-01

    Full Text Available Intact human adult articular cartilage is central for the functioning of the articulating joints. This largely depends on the integrity of its extracellular matrix, given the high loading forces during movements in particular in the weight-bearing joints. Unlike the first impression of a more or less static tissue, articular cartilage shows - albeit in the adult organism a slow - tissue turnover. Thus, one of the most important questions in osteoarthritis research is to understand the balance of catabolic and anabolic factors in articular cartilage as this is the key to understand the biology of cartilage maintenance and degeneration. Anabolic and catabolic pathways are very much intermingled in articular cartilage. The balance between anabolism and catabolism is titrated on numerous levels, starting from the mediator-synthesizing cells which express either catabolic or anabolic factors. Also, on the level of the effector cells (i.e. chondrocytes anabolic and catabolic gene expression compete for a balance of matrix homeostasis, namely the synthesis of matrix components and the expression and activation of matrix-degrading proteases. Also, there are multiple layers of intracellular cross-talks in between the anabolic and catabolic signalling pathways. Maybe the most important lesson from this overview is the notion that the anabolic-catabolic balance as such counts and not so much sufficient net anabolism or limited catabolism alone. Thus, it might be neither the aim of osteoarthritis therapy to foster anabolism nor to knock down catabolism, but the balance of anabolic-catabolic activities as a total might need proper titration and balancing.

  14. Analisis Hubungan Receivable Turnover Ratio, Inventory Turnover Ratio, dan Total Asset Turnover Ratio Dengan Kemampulabaan Perusahaan Pada PTPN III (Persero) Medan

    OpenAIRE

    Panjaitan, Fitry Bertha H.

    2010-01-01

    Tujuan penelitian adalah untuk menganalisis hubungan Receivable Turnover Ratio, Inventory Turnover Ratio, dan Total Asset Turnover Ratio dengan kemampulabaan perusahaan pada PTPN III (Persero) Medan. Penulis menarik hipotesis bahwa Receivable Turnover Ratio, Inventory Turnover Ratio, dan Total Asset Turnover Ratio berhubungan positif dengan kemampulabaan perusahaan pada PTPN III (Persero) Medan. Metode penelitian yang digunakan adalah metode analisis deskriptif dan metode analisis K...

  15. Multi-parametric MRI characterization of enzymatically degraded articular cartilage.

    Science.gov (United States)

    Nissi, Mikko J; Salo, Elli-Noora; Tiitu, Virpi; Liimatainen, Timo; Michaeli, Shalom; Mangia, Silvia; Ellermann, Jutta; Nieminen, Miika T

    2016-07-01

    Several laboratory and rotating frame quantitative MRI parameters were evaluated and compared for detection of changes in articular cartilage following selective enzymatic digestion. Bovine osteochondral specimens were subjected to 44 h incubation in control medium or in collagenase or chondroitinase ABC to induce superficial collagen or proteoglycan (glycosaminoglycan) alterations. The samples were scanned at 9.4 T for T1 , T1 Gd (dGEMRIC), T2 , adiabatic T1 ρ , adiabatic T2 ρ , continuous-wave T1 ρ , TRAFF2 , and T1 sat relaxation times and for magnetization transfer ratio (MTR). For reference, glycosaminoglycan content, collagen fibril orientation and biomechanical properties were determined. Changes primarily in the superficial cartilage were noted after enzymatic degradation. Most of the studied parameters were sensitive to the destruction of collagen network, whereas glycosaminoglycan depletion was detected only by native T1 and T1 Gd relaxation time constants throughout the tissue and by MTR superficially. T1 , adiabatic T1 ρ , adiabatic T2 ρ , continuous-wave T1 ρ , and T1 sat correlated significantly with the biomechanical properties while T1 Gd correlated with glycosaminoglycan staining. The findings indicated that most of the studied MRI parameters were sensitive to both glycosaminoglycan content and collagen network integrity, with changes due to enzymatic treatment detected primarily in the superficial tissue. Strong correlation of T1 , adiabatic T1ρ , adiabatic T2 ρ , continuous-wave T1 ρ , and T1 sat with the altered biomechanical properties, reflects that these parameters were sensitive to critical functional properties of cartilage. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:1111-1120, 2016. PMID:26662555

  16. Regulatory Challenges for Cartilage Repair Technologies.

    Science.gov (United States)

    McGowan, Kevin B; Stiegman, Glenn

    2013-01-01

    In the United States, few Food and Drug Administration (FDA)-approved options exist for the treatment of focal cartilage and osteochondral lesions. Developers of products for cartilage repair face many challenges to obtain marketing approval from the FDA. The objective of this review is to discuss the necessary steps for FDA application and approval for a new cartilage repair product. FDA Guidance Documents, FDA Panel Meetings, scientific organization recommendations, and clinicaltrials.gov were reviewed to demonstrate the current thinking of FDA and the scientific community on the regulatory process for cartilage repair therapies. Cartilage repair therapies can receive market approval from FDA as medical devices, drugs, or biologics, and the specific classification of product can affect the nonclinical, clinical, and regulatory strategy to bring the product to market. Recent FDA guidance gives an outline of the required elements to bring a cartilage repair product to market, although these standards are often very general. As a result, companies have to carefully craft their study patient population, comparator group, and clinical endpoint to best showcase their product's attributes. In addition, regulatory strategy and manufacturing process validation need to be considered early in the clinical study process to allow for timely product approval following the completion of clinical study. Although the path to regulatory approval for a cartilage repair therapy is challenging and time-consuming, proper clinical trial planning and attention to the details can eventually save companies time and money by bringing a product to the market in the most expeditious process possible. PMID:26069647

  17. The bone-cartilage unit in osteoarthritis.

    Science.gov (United States)

    Lories, Rik J; Luyten, Frank P

    2011-01-01

    Osteoarthritis (OA) refers to a group of mechanically-induced joint disorders to which both genetic and acquired factors contribute. Current pathophysiological concepts focus on OA as a disease of the whole joint. Within these models, the functional unit formed by the articular cartilage and the subchondral bone seems to be of particular interest. Cartilage and bone receive and dissipate the stress associated with movement and loading, and are therefore continuously challenged biomechanically. Recent data support the view that cartilage and bone can communicate over the calcified tissue barrier; vessels reach out from bone into the cartilage zone, patches of uncalcified cartilage are in contact with bone, and microcracks and fissures further facilitate transfer of molecules. Several molecular signaling pathways such as bone morphogenetic proteins and Wnts are hypothesized to have a role in OA and can activate cellular and molecular processes in both cartilage and bone cells. In addition, intracellular activation of different kinase cascades seems to be involved in the molecular crosstalk between cartilage and bone cells. Further research is required to integrate these different elements into a comprehensive approach that will increase our understanding of the disease processes in OA, and that could lead to the development of specific therapeutics or treatment strategies. PMID:21135881

  18. Biochemical markers of bone turnover

    International Nuclear Information System (INIS)

    Biochemical markers of bone turnover has received increasing attention over the past few years, because of the need for sensitivity and specific tool in the clinical investigation of osteoporosis. Bone markers should be unique to bone, reflect changes of bone less, and should be correlated with radiocalcium kinetics, histomorphometry, or changes in bone mass. The markers also should be useful in monitoring treatment efficacy. Although no bone marker has been established to meet all these criteria, currently osteocalcin and pyridinium crosslinks are the most efficient markers to assess the level of bone turnover in the menopausal and senile osteoporosis. Recently, N-terminal telopeptide (NTX), C-terminal telopeptide (CTX) and bone specific alkaline phosphatase are considered as new valid markers of bone turnover. Recent data suggest that CTX and free deoxypyridinoline could predict the subsequent risk of hip fracture of elderly women. Treatment of postmenopausal women with estrogen, calcitonin and bisphosphonates demonstrated rapid decrease of the levels of bone markers that correlated with the long-term increase of bone mass. Factors such as circadian rhythms, diet, age, sex, bone mass and renal function affect the results of biochemical markers and should be appropriately adjusted whenever possible. Each biochemical markers of bone turnover may have its own specific advantages and limitations. Recent advances in research will provide more sensitive and specific assays

  19. [Surgical therapeutic possibilities of cartilage damage].

    Science.gov (United States)

    Burkart, A C; Schoettle, P B; Imhoff, A B

    2001-09-01

    Therapy of cartilage damage is a frequent problem, especially in the young and active patient. For the treatment of a cartilage damage we have to consider the size of the defect, age and weight of the patient, meniscal tears, ligament instabilities and varus-/valgus-malalignment. Lavage, shaving and debridement are only sufficient for a short time and have no long term effect. Abrasio and drilling could be useful in eldery people. Microfracturing seems to be an effective alternative for small defects. The restoration of the cartilage surface with the use of autologous chondrocyte transplantation, osteochondral autograft transplantation and posterior condyle transfer seems to be an adequate treatment for younger patients. PMID:11572120

  20. Inter-subject comparison of MRI knee cartilage thickness

    OpenAIRE

    Carballido-Gamio, Julio; Jan S. Bauer; Stahl, Robert; Lee, Keh-Yang; Krause, Stefanie; Link, Thomas M.; Majumdar, Sharmila

    2007-01-01

    In this paper, we present the development and application of current image processing techniques to perform MRI inter-subject comparison of knee cartilage thickness based on the registration of bone structures. Each point in the bone surface which is part of the bone–cartilage interface is assigned a cartilage thickness value. Cartilage and corresponding bone structures are segmented and their shapes interpolated to create isotropic voxels. Cartilage thicknesses are computed for each point in...

  1. Histological comparison of the alar nasal cartilages in unilateral cleft lip

    Directory of Open Access Journals (Sweden)

    Modolin Miguel

    2002-01-01

    Full Text Available Patients with unilateral cleft lip display characteristic nasal changes that are independent of the degree of deformity. Defenders of the intrinsic theory consider these deformities to be due to embryogenic alterations of the alar nasal cartilages. Those that propose the extrinsic theory defend the thesis that the deformity is due to disorganization of the perioral muscles deformed by the cleft. The purpose of this study is to contribute histological evidence to help clarify the issue. PATIENTS AND METHODS: Specimens of the lateral portion of both the healthy and the cleft side of the alar cartilages were obtained from 18 patients. These uniformly cut specimens were stained by hematoxylin and eosin. Samples from 2 patients were excluded due to imperfections. The same pathologist examined all the slides. He was unaware of the origins of the specimens; he counted the number of chondrocytes and quantified the cartilage matrixes. RESULTS: All data was analyzed statistically, and no significant statistical differences were apparent, either in the number of chondrocytes or the cartilage matrix between the healthy side and the cleft side. DISCUSSION: These results apparently support the group that defend the extrinsic theory; nevertheless, the doubt about the composition of the cartilage matrix remains, not only concerning the glycosaminoglycans that compose them, but also regarding elastin and collagen and its linkages that can cause different degrees of collagen consistency.

  2. Holmium laser ablation of cartilage: effects of delivery fiber angle of incidence

    Science.gov (United States)

    Asshauer, Thomas; Oberthur, Thorsten; Jansen, Thomas; Gerber, Bruno E.; Delacretaz, Guy P.

    1996-01-01

    The effects of 2.12 micrometers Cr:Tm:Ho:YAG laser pulses delivered in isotonic saline solution via an optical fiber system on fresh porcine femur patellar groove cartilage were studied in vitro. Various irradiation geometry, corresponding to angles of 0 - 90 degree(s) of the delivering fiber with respect to the cartilage surface, have been investigated. A laser pulse energies of 1.0 J with a pulse duration of 250 microsecond(s) (FWHM) was used. The dynamics of the induced transient vapor bubbles and the ablation process were monitored by time resolved flash videography techniques. Acoustic transients of up to 200 bars induced by bubble collapses were measured by a calibrated piezoelectric needle probe hydrophone. Histological assessment of the irradiated cartilage samples was performed using azan and Safranin-O stains. The extent of the area of altered cartilage cells is larger than the zone of tissue matrix damage. The predominant mechanism of tissue damage is thermal rather than acousto-mechanical. Cartilage treatment at an angle of incidence of 30 degree(s) reduces significantly the overall damage as compared to 60 degree(s) or 90 degree(s) irradiation.

  3. Relating Employee Satisfaction and Voluntary Turnover

    OpenAIRE

    Janika SILLAMAE

    2010-01-01

    Voluntary turnover has been an enduring topic in organizational management theory and a subject of numerous empirical studies due to its great influence on organizations’ efficiency. Currently the goal was to investigate which employee satisfaction issues relate to turnover intentions and do they relate to actual voluntary turnover. The empirical study was conducted in Estonian government office: questionnaire describing employee satisfaction and turnover intentions was carried out twice and ...

  4. Employee Turnover in MFIs: Reasons & Remedies

    OpenAIRE

    Sk. Mahmudul Alam, Mahmud

    2015-01-01

    At present day’s employee turnover is one of the challenging issues in microfinance sector of Bangladesh. Excessive turnover is not only pricey, but it can create a bad reputation in the MFI sector and among the job seekers. Excessive turnover may be harmful to an MFI's productivity if experienced and efficient employees are often departing and the employee encompasses a high percentage of beginners. The impact of turnover has received substantial attention by the senior management and human ...

  5. Migration Turnover Rates in Mountain States Counties

    OpenAIRE

    Israelsen, William J.; Israelsen, L. Dwight; Israelsen, Ryan D.

    2006-01-01

    Studies of migration typically examine migration between countries, or, in the United States, migration between states. Recently, there have been several studies done on the determinants of migration at the county level. The current study introduces a new concept into the migration literature: the migration turnover rate (MTR). The migration turnover rate is similar to an employee turnover rate in that it measures the turnover through in-migration and out-migration of the population of an are...

  6. Migration Turnover Rates in United States Counties

    OpenAIRE

    Israelsen, L. Dwight; Israelsen, Ryan D.; Israelsen, William J.

    2006-01-01

    Studies of migration typically examine migration between countries, or, in the United States, migration between states. Recently, there have been several studies done on the determinants of migration at the county level. The current study introduces a new concept into the migration literature: the migration turnover rate (MTR). The migration turnover rate is similar to an employee turnover rate in that it measures the turnover through in-migration and out-migration of the population of an are...

  7. Using Turnover as a Recruitment Strategy

    Science.gov (United States)

    Duncan, Sandra

    2009-01-01

    Teacher turnover is notoriously high in the field of early childhood education with an estimated 33% of staff exiting the workplace each year. Turnover is costly. Not only do high levels of turnover negatively impact children's growth and development, it also erodes the program's economic stability and wherewithal to provide effective operations…

  8. How Teacher Turnover Harms Student Achievement

    Science.gov (United States)

    Ronfeldt, Matthew; Loeb, Susanna; Wyckoff, James

    2013-01-01

    Researchers and policymakers often assume that teacher turnover harms student achievement, though recent studies suggest this may not be the case. Using a unique identification strategy that employs school-by-grade level turnover and two classes of fixed-effects models, this study estimates the effects of teacher turnover on over 850,000 New York…

  9. Estimating Teacher Turnover Costs: A Case Study

    Science.gov (United States)

    Levy, Abigail Jurist; Joy, Lois; Ellis, Pamela; Jablonski, Erica; Karelitz, Tzur M.

    2012-01-01

    High teacher turnover in large U.S. cities is a critical issue for schools and districts, and the students they serve; but surprisingly little work has been done to develop methodologies and standards that districts and schools can use to make reliable estimates of turnover costs. Even less is known about how to detect variations in turnover costs…

  10. A Spectral Model of Turnover Reduction

    OpenAIRE

    Zura Kakushadze

    2014-01-01

    We give a simple explicit formula for turnover reduction when a large number of alphas are traded on the same execution platform and trades are crossed internally. We model turnover reduction via alpha correlations. Then, for a large number of alphas, turnover reduction is related to the largest eigenvalue and the corresponding eigenvector of the alpha correlation matrix.

  11. Increasing turnover through time in tropical forests

    OpenAIRE

    Phillips, O. L; Gentry, A.H.

    1994-01-01

    Tree turnover rates were assessed at 40 tropical forest sites. Averaged across inventoried forests, turnover, as measured by tree mortality and recruitment, has increased since the 1950's, with an apparent pantropical acceleration since 1980. Among 22 mature forest sites with two or more inventory periods, forest turnover also increased. The trend in forest dynamics may have profound effects on biological diversity.

  12. Chronic Teacher Turnover in Urban Elementary Schools

    Science.gov (United States)

    Guin, Kacey

    2004-01-01

    This study examines the characteristics of elementary schools that experience chronic teacher turnover and the impacts of turnover on a school's working climate and ability to effectively function. Based on evidence from staff climate surveys and case studies, it is clear that high turnover schools face significant organizational challenges.…

  13. Benchmarking of homogeneous electrocatalysts: overpotential, turnover frequency, limiting turnover number.

    Science.gov (United States)

    Costentin, Cyrille; Passard, Guillaume; Savéant, Jean-Michel

    2015-04-29

    In relation to contemporary energy challenges, a number of molecular catalysts for the activation of small molecules, mainly based on transition metal complexes, have been developed. The time has thus come to develop tools allowing the benchmarking of these numerous catalysts. Two main factors of merit are addressed. One involves their intrinsic catalytic performances through the comparison of "catalytic Tafel plots" relating the turnover frequency to the overpotential independently of the characteristics of the electrochemical cell. The other examines the effect of deactivation of the catalyst during the course of electrolysis. It introduces the notion of the limiting turnover number as a second key element of catalyst benchmarking. How these two factors combine with one another to control the course of electrolysis is analyzed in detail, leading to procedures that allow their separate estimation from measurements of the current, the charge passed, and the decay of the catalyst concentration. Illustrative examples from literature data are discussed. PMID:25757058

  14. Controlled-Potential Electromechanical Reshaping of Cartilage.

    Science.gov (United States)

    Hunter, Bryan M; Kallick, Jeremy; Kissel, Jessica; Herzig, Maya; Manuel, Cyrus; Protsenko, Dmitri; Wong, Brian J F; Hill, Michael G

    2016-04-25

    An alternative to conventional "cut-and-sew" cartilage surgery, electromechanical reshaping (EMR) is a molecular-based modality in which an array of needle electrodes is inserted into cartilage held under mechanical deformation by a jig. Brief (ca. 2 min) application of an electrochemical potential at the water-oxidation limit results in permanent reshaping of the specimen. Highly sulfated glycosaminoglycans within the cartilage matrix provide structural rigidity to the tissue through extensive ionic-bonding networks; this matrix is highly permselective for cations. Our studies indicate that EMR results from electrochemical generation of localized, low-pH gradients within the tissue: fixed negative charges in the proteoglycan matrix are protonated, resulting in chemically induced stress relaxation of the tissue. Re-equilibration to physiological pH restores the fixed negative charges, and yields remodeled cartilage that retains a new shape approximated by the geometry of the reshaping jig. PMID:27059655

  15. The structure and function of cartilage proteoglycans

    Directory of Open Access Journals (Sweden)

    P J Roughley

    2006-11-01

    Full Text Available Cartilage contains a variety of proteoglycans that are essential for its normal function. These include aggrecan, decorin, biglycan, fibromodulin and lumican. Each proteoglycan serves several functions that are determined by both its core protein and its glycosaminoglycan chains. This review discusses the structure/function relationships of the cartilage proteoglycans, and the manner in which perturbations in proteoglycan structure or abundance can adversely affect tissue function.

  16. Fibrin for tissue engineering of cartilage

    OpenAIRE

    Eyrich, Daniela

    2006-01-01

    Since the beginning of the 1990s a plethora of research approaches towards cartilage engineering for plastic and reconstructive surgery have been undertaken. However, a general standard method for generation of cartilage tissue equivalent is still lacking. The goal of this thesis is based on the project �Bavarian Research Cooperation for Tissue Engineering and Rapid Prototyping� (ForTEPro) for development of individually customized implants for facial and reconstructive surgery. The main o...

  17. Materials science: Like cartilage, but simpler

    DEFF Research Database (Denmark)

    Skov, Anne Ladegaard

    2015-01-01

    The properties of articular cartilage, which lines bones in joints, depend partlyon repulsion between components of the material. A new synthetic gel that mimics this feature has rare, direction-dependent properties.......The properties of articular cartilage, which lines bones in joints, depend partlyon repulsion between components of the material. A new synthetic gel that mimics this feature has rare, direction-dependent properties....

  18. Partial Genetic Turnover in Neandertals

    DEFF Research Database (Denmark)

    Dalén, Love; Orlando, Ludovic Antoine Alexandre; Shapiro, Beth;

    2012-01-01

    Remarkably little is known about the population-level processes leading up to the extinction of the neandertal. To examine this, we use mtDNA sequences from 13 neandertal individuals, including a novel sequence from northern Spain, to examine neandertal demographic history. Our analyses indicate ...... population. The most parsimonious explanation for these results is that of a population turnover in western Europe during early Marine Isotope Stage 3, predating the arrival of anatomically modern humans in the region....

  19. Firm turnover and inflation dynamics

    OpenAIRE

    Lenno Uusküla

    2015-01-01

    This paper examines the role of firm turnover in explaining inflation dynamics. I augment a New-Keynesian DSGE model with endogenous entry and exogenous stochastic exit and estimate with the Bayesian full information approach for the US economy. Results show that shocks to the entry cost explain more than half of the inflation variance at the business cycle frequencies. When it is cheap to create firms, the number of new firms goes up and inflation increases as labour intensive creation of fi...

  20. Labour Market Turnover and Mobility

    OpenAIRE

    Patrick D’Arcy; Linus Gustafsson; Christine Lewis; Trent Wiltshire

    2012-01-01

    Labour mobility plays a role in allocating workers to suitable jobs and is important in helping the economy adjust to shocks and structural change. But there are also benefits from longer job tenure, and costs associated with workers changing jobs. This article presents some stylised facts about labour market movements and the role that labour mobility has played in facilitating economic adjustment over the past decade. While most worker turnover is associated with the normal process of worke...

  1. Managing employee turnover in China

    OpenAIRE

    Rinne, Tuua

    2013-01-01

    OBJECTIVES OF THE STUDY: Many international companies are facing challenges in retaining their top talent in the Chinese talent war. This single case study provides a description on how voluntary employee turnover is managed in a Chinese subsidiary of a Finnish multinational enterprise. First objective of this study aims at explaining why Chinese employees stay in or leave the company. The second goal is to analyze how multicultural context affect the adoption of different retention pract...

  2. Turnover: strategies for staff retention.

    Science.gov (United States)

    SnowAntle, S

    1990-01-01

    This discussion has focused on a number of areas where organizations may find opportunities for more effectively managing employee retention. Given the multitude of causes and consequences, there is no one quick fix. Effective management of employee retention requires assessment of the entire human resources process, that is, recruitment, selection, job design, compensation, supervision, work conditions, etc. Regular and systematic diagnosis of turnover and implementation of multiple strategies and evaluation are needed (Mobley, 1982). PMID:10106673

  3. Magnetic resonance imaging of articular cartilage at 3 tesla

    International Nuclear Information System (INIS)

    Smooth motor function can be maintained by articular cartilage. When the cartilage is injured, edema occurs, and as degeneration progresses, the cartilage thins and the cartilage matrix decreases. Magnetic resonance (MR) imaging allows noninvasive evaluation of these changes. Fat suppression proton density- and T2-weighted imaging are useful in the morphologic evaluation of articular cartilage. High resolution, 3-tesla MR imaging provides more detailed evaluation. Biochemical information from T2 mapping, T1ρ mapping, and delayed gadolinium-enhanced MR imaging of cartilage (dGEMRIC) is useful for early diagnosis of cartilage injury and evaluation of cartilage repair. The role of MR imaging in evaluating articular cartilage will increase in the future aging society. (author)

  4. CEO Turnover and Market Reaction in Indonesia

    Directory of Open Access Journals (Sweden)

    Doddy Setiawan

    2013-07-01

    Full Text Available This research examines Chief Executive Officer (CEO turnover and market reaction in Indonesia. The sample of this research consists of 213 CEO turnover announcements for Indonesia Stock Exchange during 2000–2010 period. T-tests were used to investigate the effect of CEO turnover announcement on abnormal stock return during the event windows periods. The results of this research show that there is positive reaction on the CEO turnover announcements. This research considers both routine and non routine CEO turnover processes. This research finds that both turnover processes have information content to investor. This research also finds positive reaction on the announcements of outsider incoming CEO, while investors do not react on the announcement of insider incoming CEO. Thus, this research provides evidence that CEO turnover announcement have information content.

  5. Study of the collagen structure in the superficial zone and physiological state of articular cartilage using a 3D confocal imaging technique

    Directory of Open Access Journals (Sweden)

    Zheng Ming H

    2008-07-01

    the collagen network in the superficial zone during early physiological alteration of articular cartilage. The fibre confocal imaging technology used in this study has allowed developing confocal arthroscopy for in vivo studying the chondrocytes in different depth of articular cartilage. Therefore, the current study has potential to develop an in vivo 3D histology for diagnosis of early osteoarthritis.

  6. In end stage osteoarthritis, cartilage tissue pentosidine levels are inversely related to parameters of cartilage damage

    NARCIS (Netherlands)

    Vos, P.A.J.M.; Mastbergen, S.C.; Huisman, A.M.; Boer, T.N.de; Groot, J.de; Polak, A.A.; Lafeber, F.P.J.G.

    2012-01-01

    Objectives: Age is the most prominent predisposition for development of osteoarthritis (OA). Age-related changes of articular cartilage are likely to play a role. Advanced glycation endproducts (AGEs) accumulate in cartilage matrix with increasing age and adversely affect the biomechanical propertie

  7. Correction of Asian Short Nose with Lower Lateral Cartilage Repositioning and Ear Cartilage Grafting

    Directory of Open Access Journals (Sweden)

    Jin Suk Byun, MD, PhD

    2013-09-01

    Conclusions: LLC repositioning and ear cartilage grafting aid in the correction of short nose in Asians. With LLC repositioning and ear cartilage grafting, the nasal tip can be positioned in accordance with the patient’s anatomic limits. The entire nasal tip and columella can be lengthened, while the tip maintains its mobility.

  8. Aggrecan structure in amphibian cartilage

    Directory of Open Access Journals (Sweden)

    Covizi D.Z.

    2000-01-01

    Full Text Available The structure of the large proteoglycan present in the bullfrog epiphyseal cartilage was studied by immunochemical and biochemical methods. The isolated monomer showed a polydisperse behavior on Sepharose CL2B, with a peak at Kav = 0.14. Chondroitin sulfate chains were identified by HPLC analysis of the products formed by chondroitinase digestion and mercuric acetate treatment. These chains have approximately 38 disaccharides, a Di45:Di68 ratio of 1.6 and GalNAc4S + GalNAc4,6S are the main non-reducing terminals. Keratan sulfate was identified by the use of two monoclonal antibodies in Western blots after chondroitinase ABC treatment. A keratan sulfate-rich region (~110 kDa was isolated by sequential treatment with chondroitinase ABC and proteases. We also employed antibodies in Western blotting experiments and showed that the full length deglycosylated core protein is about 300 kDa after SDS-PAGE. Domain-specific antibodies revealed the presence of immunoreactive sites corresponding to G1/G2 and G3 globular domains and the characterization of this large proteoglycan as aggrecan. The results indicate the high conservation of the aggrecan domain structure in this lower vertebrate.

  9. "Changes in cartilage of rats after treatment with Quinolone and in Magnesium-deficient diet "

    Directory of Open Access Journals (Sweden)

    Shakibaei M

    2002-07-01

    Full Text Available Ultrastructural changes in immature articular carilage were studied after treatment of 5-weeks-old rats with ofloxacin, a fluoroquinolone, and in magnesium deficiency.We concluded that quinolone-induced arthropathy is probably due to chelation of functionally available magnesium in joint cartilage as magnesium deficiency in joint cartilage could impair chondrocyte-matrix- interaction which is mediated by cation-dependent integrin-receptors of the β1-subfamily. With immuno-histochemical methods using monoclonal and polyclonal antibodies we showed that B1 integrins were expressed in rat joint cartilage. Joint cartilage lesions were detected in ofloxacin-treated and magnesium-deficient rats. Lesions were more pronounced in the quinolone-treated group. Expression of several integrins was reduced in the vicinity of lesions after oral treatment with 2×600 mg ofloxacin/kg body wt for one day. Gross-structural lesions (e.g. cleft formation, unmasked collagen fibres in magnesium deficient rats were very similar but changes in intergrin expression were less pronounced. Alterations observed on the ultrastructural level showed striking similarities in magnesium-deficient rats and in rats treated with single doses of 600 mg ofloxacin per kg body wt.Typical observation were: bundle shaped, electron-dense aggregates on the surface and in the cytoplasm of chondrocytes, detachement of the cell membrance from the matrix and necrotic chondrocytes, reduced synthesis and/or reduced of extracellular matrix and swelling of cell organelles such as mitochondria.The results of this study confirm our previously reported finding that quinolone-induced arthropathy probably is caued by a reduction of functionally available magnesium (ionized Mg2+ in cartilage. Furthermore, they provide a basis for aimed studies with human cartilage samples from quinolone-treated patients which might be available postmortal or after hip replacement surgery

  10. Cartilage loss patterns within femorotibial contact regions during deep knee bend.

    Science.gov (United States)

    Michael Johnson, J; Mahfouz, Mohamed R

    2016-06-14

    Osteoarthritis (OA) can alter knee kinematics and stresses. The relationship between cartilage loss in OA and kinematics is unclear, with existing work focusing on static wear and morphology. In this work, femorotibial cartilage maps were coupled with kinematics to investigate the relationship between kinematics and cartilage loss, allowing for more precise treatment and intervention. Cartilage thickness maps were created from healthy and OA subgroups (varus, valgus, and neutral) and mapped to a statistical bone atlas. Video fluoroscopy determined contact regions from 0° to 120° flexion. Varus and valgus subgroups displayed different wear patterns across the range of flexion, with varus knees showing more loss in early flexion and valgus in deeper flexion. For the femur, varus knees had more wear in the medial compartment than neutral or valgus and most wear at both 0° and 20° flexion. In the lateral femoral compartment, the valgus subgroup showed significantly more wear from 20° to 60° flexion as compared to other angles, though varus knees displayed highest magnitude of wear. For the tibia, most medial wear occurred at 0-40° flexion and most lateral occurred after 60° flexion. Knowing more about cartilage changes in OA knees provides insight as to expected wear or stresses on implanted components after arthroplasty. Combining cartilage loss patterns with kinematics allows for pre-surgical intervention and treatments tailored to the patient׳s alignment and kinematics. Reported wear patterns may also serve as a gauge for post-operative loading to be considered when placing implant components. PMID:27173594

  11. Biochemical markers of type II collagen breakdown and synthesis are positioned at specific sites in human osteoarthritic knee cartilage

    DEFF Research Database (Denmark)

    Jensen, Anne-Christine Bay; Levin Andersen, Thomas; Charni-Ben Tabassi, N;

    2007-01-01

    OBJECTIVE: To investigate whether type II collagen turnover markers used for osteoarthritis (OA) activity evaluation in body fluids can be detected at the level of specific histological features of OA cartilage tissue, as well as how they relate with each other at this level. METHODS: Adjacent...... sections were obtained from full-depth cartilage biopsies from 32 OA knees. Immunohistochemistry was performed for Helix-II and CTX-II, which are type II collagen fragments originating from the triple helix and the telopeptide region, respectively, and believed to reflect distinct breakdown events, as well...... as for type IIA N propeptide (PIIANP), a biochemical marker reflecting synthesis of type IIA collagen. RESULTS: Helix-II and CTX-II were detected in areas where collagen damage was reported previously, most frequently around chondrocytes, but also frequently in regions not previously investigated...

  12. Articular cartilage: from formation to tissue engineering.

    Science.gov (United States)

    Camarero-Espinosa, Sandra; Rothen-Rutishauser, Barbara; Foster, E Johan; Weder, Christoph

    2016-05-26

    Hyaline cartilage is the nonlinear, inhomogeneous, anisotropic, poro-viscoelastic connective tissue that serves as friction-reducing and load-bearing cushion in synovial joints and is vital for mammalian skeletal movements. Due to its avascular nature, low cell density, low proliferative activity and the tendency of chondrocytes to de-differentiate, cartilage cannot regenerate after injury, wear and tear, or degeneration through common diseases such as osteoarthritis. Therefore severe damage usually requires surgical intervention. Current clinical strategies to generate new tissue include debridement, microfracture, autologous chondrocyte transplantation, and mosaicplasty. While articular cartilage was predicted to be one of the first tissues to be successfully engineered, it proved to be challenging to reproduce the complex architecture and biomechanical properties of the native tissue. Despite significant research efforts, only a limited number of studies have evolved up to the clinical trial stage. This review article summarizes the current state of cartilage tissue engineering in the context of relevant biological aspects, such as the formation and growth of hyaline cartilage, its composition, structure and biomechanical properties. Special attention is given to materials development, scaffold designs, fabrication methods, and template-cell interactions, which are of great importance to the structure and functionality of the engineered tissue. PMID:26923076

  13. Tritium turnover in succulent plants

    International Nuclear Information System (INIS)

    Measurements of turnover rates for tissue free water tritium (TFWT) and tissue bound tritium (TBT) were carried out in three succulent plants, Opuntia sp., E. Trigona and E. Mili using tritiated water as tracer. The estimated half-times were 52, 57.5 and 80 days for TFWT and 212, 318 and 132 days for TBT in the stems of the above plants respectively. Opuntia sp. showed significant incorporation of TBT, 10% of TFWT on weight basis, while the other two plants showed lesser incorporation, 2-3% of TFWT. However, the leaves of E. Mili indicated the same level of fixation of TBT as the stem of Opuntia sp. (author)

  14. Optimal Employee Turnover Rate: Theory and Evidence

    OpenAIRE

    Mark N. Harris; Kam-Ki Tang; Yi-Ping Tseng

    2002-01-01

    This paper investigates the quantitative effects of employee turnover on firms’ productivity. The Australian Business Longitudinal Survey 1995-98, a unique survey providing firm level data on both production and employee turnover, is used as the data source. Theoretical studies have advocated that firm specific human capital and job matching to be the two major, but competing, mechanisms through which turnover affects productivity. Our results indicate that the effect of job matching dominate...

  15. Measuring Employee Turnover in Australian Pig Production

    OpenAIRE

    Evans, Emma; Bent, Martin J.M.

    2002-01-01

    Limited availability of competent and motivated staff has been repeatedly cited as one of the major constraints on pig production in Australia. Whilst a considerable effort is put into training staff (Western Australia boasts the most advanced training facility in South-East Asia), practically nothing is known about the rates of employee turnover. Based on a postal survey and case studies of high and low turnover piggeries, this paper provides the first objective measures of staff turnover in...

  16. Labour Turnover and Unionism in Italy

    OpenAIRE

    Dell'Aringa, Carlo; Lucifora, Claudio

    1996-01-01

    Recent research on the functioning of labour markets has placed great emphasis on the role of job turnover. Turnover rates have important implications for wage determination, work organisation, career prospects and various other aspects of the employment relationship. A topic which has not received much attention in the literature is concerned with the impact of unions on firms' accession-separation decisions. Union practices are deemed to have a significant impact on firms' turnover rate inf...

  17. Structural adjustment, job turnover and career progression

    OpenAIRE

    Spiros Bougheas; Carl Davidson; Richard Upward; Peter Wright

    2015-01-01

    We develop a dynamic, stochastic, multi-sectoral, equilibrium model that allows for worker turnover, job turnover and career mobility. This serves to bridge the literatures on job reallocation and career progression. Our model makes a number of predictions: a positive correlation between job turnover rates and promotion rates; a positive correlation across sectors between mean real income and their corresponding variance; an inverse relationship between sector profitability and both the job t...

  18. Linking global turnover of species and environments

    OpenAIRE

    Buckley, Lauren B.; Jetz, Walter

    2008-01-01

    Patterns of species turnover are central to the geography of biodiversity and resulting challenges for conservation, but at broad scales remain relatively little understood. Here, we take a first spatially-explicitly and global perspective to link the spatial turnover of species and environments. We compare how major groups of vertebrate ectotherms (amphibians) and endotherms (birds) respond to spatial environmental gradients. We find that high levels of species turnover occur regardless of e...

  19. Preparation and characterization of a decellularized cartilage scaffold for ear cartilage reconstruction

    International Nuclear Information System (INIS)

    Scaffolds are widely used to reconstruct cartilage. Yet, the fabrication of a scaffold with a highly organized microenvironment that closely resembles native cartilage remains a major challenge. Scaffolds derived from acellular extracellular matrices are able to provide such a microenvironment. Currently, no report specifically on decellularization of full thickness ear cartilage has been published. In this study, decellularized ear cartilage scaffolds were prepared and extensively characterized. Cartilage decellularization was optimized to remove cells and cell remnants from elastic cartilage. Following removal of nuclear material, the obtained scaffolds retained their native collagen and elastin contents as well as their architecture and shape. High magnification scanning electron microscopy showed no obvious difference in matrix density after decellularization. However, glycosaminoglycan content was significantly reduced, resulting in a loss of viscoelastic properties. Additionally, in contact with the scaffolds, human bone-marrow-derived mesenchymal stem cells remained viable and are able to differentiate toward the chondrogenic lineage when cultured in vitro. These results, including the ability to decellularize whole human ears, highlight the clinical potential of decellularization as an improved cartilage reconstruction strategy. (paper)

  20. Effect of estrogen and dietary loading on rat condylar cartilage

    OpenAIRE

    Orajärvi, M. (Marko)

    2015-01-01

    Abstract The temporomandibular joint (TMJ) is a synovial joint which attaches the mandible to the skull. The head of the mandibular condyle is covered by condylar cartilage, which functions as both growth and articular cartilage. Masticatory forces are transmitted to the condylar cartilage, and the consistency of a person’s diet partly defines the loading force. Condylar cartilage acts as a load-absorbing structure together with the articular disc. Temporomandibular disorders (TMDs) are...

  1. Engineering articular cartilage using newly developed carrageenan basedhydrogels

    OpenAIRE

    Popa, Elena Geta

    2014-01-01

    Articular cartilage holds specific functionality in the human body creating smooth gliding areas and allowing the joints to move easily without pain. However, due to its avascular nature and to the low metabolic activity of the constituent cells-the chondrocytes, cartilage has a low regenerative potential. The current surgical options to treat damaged cartilage are not long lasting and involve frequent revisions. Tissue engineering may provide an alternative approach for cartilage...

  2. Type III Collagen, a Fibril Network Modifier in Articular Cartilage*

    OpenAIRE

    Wu, Jiann-Jiu; Weis, Mary Ann; Kim, Lammy S.; Eyre, David R.

    2010-01-01

    The collagen framework of hyaline cartilages, including articular cartilage, consists largely of type II collagen that matures from a cross-linked heteropolymeric fibril template of types II, IX, and XI collagens. In the articular cartilages of adult joints, type III collagen makes an appearance in varying amounts superimposed on the original collagen fibril network. In a study to understand better the structural role of type III collagen in cartilage, we find that type III collagen molecules...

  3. Competition, Firm Turnover and Productivity Growth

    OpenAIRE

    Gu, Wulong; Baldwin, John R.

    2006-01-01

    This paper investigates the extent to which productivity growth is the result of firm turnover as output is shifted from one firm to another, driven by the competitive process. Turnover occurs as some firms gain market share and others lose it. Some of the resulting turnover is due to entry and exit. Another part arises from growth and decline in incumbent continuing firms. This paper proposes a method for measuring the impact of firm turnover on productivity growth and shows that it is far m...

  4. The validation of the turnover intention scale

    OpenAIRE

    Chris F.C. Bothma; Gert Roodt

    2013-01-01

    Orientation: Turnover intention as a construct has attracted increased research attention in the recent past, but there are seemingly not many valid and reliable scales around to measure turnover intention.Research purpose: This study focused on the validation of a shortened, six-item version of the turnover intention scale (TIS-6).Motivation for the study: The research question of whether the TIS-6 is a reliable and a valid scale for measuring turnover intention and for predicting actual tur...

  5. Irradiated homologous costal cartilage for augmentation rhinoplasty

    International Nuclear Information System (INIS)

    Although the ideal reconstructive material for augmentation rhinoplasty continues to challenge plastic surgeons, there exists no report in the literature that confines the use of irradiated homologous costal cartilage, first reported by Dingman and Grabb in 1961, to dorsal nasal augmentation. The purpose of this paper is to present a retrospective analysis of the author's experience using irradiated homologous costal cartilage in augmentation rhinoplasty. Twenty-seven dorsal nasal augmentations were performed in 24 patients between 16 and 49 years of age with a follow-up ranging from 1 to 27 months. Good-to-excellent results were achieved in 83.3% (20 of 24). Poor results requiring revision were found in 16.7% (4 of 24). Complication rates included 7.4% infection (2 of 27) and 14.8% warping (4 of 27). The resorption rate was zero. These results compare favorably with other forms of nasal augmentation. Advantages and disadvantages of irradiated homologous costal cartilage are discussed

  6. Development of artificial articular cartilage

    Indian Academy of Sciences (India)

    Biswajit Bera

    2009-10-01

    The present study describes the development of artificial articular cartilage on the basis of mimicking structural gel properties and mechanical gel properties of natural articular cartilage. It is synthesized from PVA/Si nanocomposite containing 20% Tetra ethoxy silane (TEOS) by sol–gel method. Mechanical strength of Poly(vinyl alcohol), PVA is improved up to 35 MPa. Manufacturing method is adopted considering colloidal stability of nano silica particle in PVA sol at specific pH = 1. An adhesive is also prepared from PVA/Si nanocomposite containing 40% TEOS for firm attachment of artificial articular cartilage on underlying bone with high bond strength.

  7. Semi-automatic knee cartilage segmentation

    Science.gov (United States)

    Dam, Erik B.; Folkesson, Jenny; Pettersen, Paola C.; Christiansen, Claus

    2006-03-01

    Osteo-Arthritis (OA) is a very common age-related cause of pain and reduced range of motion. A central effect of OA is wear-down of the articular cartilage that otherwise ensures smooth joint motion. Quantification of the cartilage breakdown is central in monitoring disease progression and therefore cartilage segmentation is required. Recent advances allow automatic cartilage segmentation with high accuracy in most cases. However, the automatic methods still fail in some problematic cases. For clinical studies, even if a few failing cases will be averaged out in the overall results, this reduces the mean accuracy and precision and thereby necessitates larger/longer studies. Since the severe OA cases are often most problematic for the automatic methods, there is even a risk that the quantification will introduce a bias in the results. Therefore, interactive inspection and correction of these problematic cases is desirable. For diagnosis on individuals, this is even more crucial since the diagnosis will otherwise simply fail. We introduce and evaluate a semi-automatic cartilage segmentation method combining an automatic pre-segmentation with an interactive step that allows inspection and correction. The automatic step consists of voxel classification based on supervised learning. The interactive step combines a watershed transformation of the original scan with the posterior probability map from the classification step at sub-voxel precision. We evaluate the method for the task of segmenting the tibial cartilage sheet from low-field magnetic resonance imaging (MRI) of knees. The evaluation shows that the combined method allows accurate and highly reproducible correction of the segmentation of even the worst cases in approximately ten minutes of interaction.

  8. Deficient Mechanical Activation of Anabolic Transcripts and Post-Traumatic Cartilage Degeneration in Matrilin-1 Knockout Mice

    Science.gov (United States)

    Chen, Yupeng; Cossman, Jack; Jayasuriya, Chathuraka T.; Li, Xin; Guan, Yingjie; Fonseca, Vera; Yang, Kun; Charbonneau, Cherie; Yu, Hongchuan; Kanbe, Katsuaki; Ma, Peter; Darling, Eric; Chen, Qian

    2016-01-01

    Matrilin-1 (Matn1), a cartilage-specific peri-cellular and extracellular matrix (ECM) protein, has been hypothesized to regulate ECM interactions and transmit mechanical signals in cartilage. Since Matn1 knock-out (Matn1-/-) mice exhibit a normal skeleton, its function in vivo is unclear. In this study, we found that the anabolic Acan and Col2a transcript levels were significantly higher in wildtype (Matn1+/+) mouse cartilage than that of MATN1-/- mice in vivo. However, such difference was not observed between Matn1+/+ and MATN1-/- chondrocytes cultured under stationary conditions in vitro. Cyclic loading significantly stimulated Acan and Col2a transcript levels in Matn1+/+ but not in MATN1-/- chondrocytes. This suggests that, while Matn1+/+ chondrocytes increase their anabolic gene expression in response to mechanical loading, the MATN1-/- chondrocytes fail to do so because of the deficiency in mechanotransduction. We also found that altered elastic modulus of cartilage matrix in Matn1-/- mice, suggesting the mechanotransduction has changed due to the deficiency of Matn1. To understand the impact of such deficiency on joint disease, mechanical loading was altered in vivo by destabilization of medial meniscus. While Matn1+/+ mice exhibited superficial fissures and clefts consistent with mechanical damage to the articular joint, Matn1-/- mice presented more severe cartilage lesions characterized by proteoglycan loss and disorganization of cells and ECM. This suggests that Matn1 deficiency affects pathogenesis of post-traumatic osteoarthritis by failing to up-regulate anabolic gene expression. This is the first demonstration of Matn1 function in vivo, which suggests its protective role in cartilage degeneration under altered mechanical environment. PMID:27270603

  9. Tissue engineering of cartilage in space

    OpenAIRE

    Freed, Lisa E.; Langer, Robert; Martin, Ivan; Pellis, Neal R.; Vunjak-Novakovic, Gordana

    1997-01-01

    Tissue engineering of cartilage, i.e., the in vitro cultivation of cartilage cells on synthetic polymer scaffolds, was studied on the Mir Space Station and on Earth. Specifically, three-dimensional cell-polymer constructs consisting of bovine articular chondrocytes and polyglycolic acid scaffolds were grown in rotating bioreactors, first for 3 months on Earth and then for an additional 4 months on either Mir (10−4–10−6 g) or Earth (1 g). This mission provided a unique opportunity to study the...

  10. Dynamic Aspects of Voluntary Turnover: An Integrated Approach to Curvilinearity in the Performance-Turnover Relationship

    Science.gov (United States)

    Becker, William J.; Cropanzano, Russell

    2011-01-01

    Previous research pertaining to job performance and voluntary turnover has been guided by 2 distinct theoretical perspectives. First, the push-pull model proposes that there is a quadratic or curvilinear relationship existing between these 2 variables. Second, the unfolding model of turnover posits that turnover is a dynamic process and that a…

  11. Characterisation of mineralisation of bone and cartilage: X-ray diffraction and Ca and Sr K{sub {alpha}} X-ray fluorescence microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Bradley, D.A. [Centre for Nuclear and Radiation Physics, Department of Physics, University of Surrey, Guildford, Surrey, GU2 7XH (United Kingdom)], E-mail: d.a.bradley@surrey.ac.uk; Muthuvelu, P.; Ellis, R.E.; Green, E.M.; Attenburrow, D. [Biomedical Physics Group, School of Physics, University of Exeter, Exeter (United Kingdom); Barrett, R. [ESRF, BP 220, F-38043 Grenoble Cedex (France); Arkill, K.; Colridge, D.B.; Winlove, C.P. [Biomedical Physics Group, School of Physics, University of Exeter, Exeter (United Kingdom)

    2007-10-15

    Bone is a dynamic structure, constantly remodelling in response to changing mechanical and environmental factors. This is particularly evident in the mineral component encrusting the collagenous framework. The mineral is principally in the form of calcium apatite, but calcium can exchange with strontium, both during the cellular processes of mineralisation and resorption and by passive exchange with the deposited crystals. Mineralisation is generally characterized by densitometry, but because of the differences in absorption cross sections of calcium and strontium it can be misleading in studies of composition. In this work we have used X-ray diffraction to identify calcium and strontium apatite and X-ray fluorescence to quantify strontium and calcium distribution. With the beam characteristics available from synchrotron radiation, this has enabled us to obtain microscopic resolution on thin sections of bone and cartilage from the equine metacarpophalangeal joint. Two issues have been investigated; the first is the distribution of mineral in the bone-cartilage interface and within individual trabeculae. In trabecular bone the ratio of strontium to calcium concentration was typically 0.0035 {+-} 0.0020, and higher by a factor of {approx}3 at the periphery than in the centre of a trabeculum (possibly reflecting the more rapid turnover of mineral in the surface layer). In the dense subchondral bone the ratio was similar, approximately doubling in the calcified cartilage. The second objective was to explore the changes in mineralisation associated with development of osteoarthrosis. We analysed lesions showing cartilage thinning and changes in the trabecular organization and density of the underlying bone. At the centre of the lesion the ratio of strontium to calcium was much lower than that in normal tissue, although the calcified cartilage still showed a higher ratio than the underlying bone. In the superficially normal tissue around the lesion the calcified

  12. Employee Turnover among Full-time Public Librarians.

    Science.gov (United States)

    Rubin, Richard

    1989-01-01

    A study of employee turnover in 31 public libraries in the American Midwest established baseline turnover rates and examined the relationship of gender to turnover behavior. Findings showed that: turnover rates are low compared to other occupations; and turnover rates of males and females are similar. (28 references) (Author/MES)

  13. Novel nano-rough polymers for cartilage tissue engineering

    Directory of Open Access Journals (Sweden)

    Balasundaram G

    2014-04-01

    Full Text Available Ganesan Balasundaram,1 Daniel M Storey,1 Thomas J Webster2,31Surfatek, Longmont, CO, USA; 2Department of Chemical Engineering, Northeastern University, Boston, MA, USA; 3Center of Excellence for Advanced Materials Research, King Abdulaziz University, Jeddah, Saudi ArabiaAbstract: This study presents an innovative method for creating a highly porous surface with nanoscale roughness on biologically relevant polymers, specifically polyurethane (PU and polycaprolactone (PCL. Nanoembossed polyurethane (NPU and nanoembossed polycaprolactone (NPCL were produced by the casting of PU and PCL over a plasma-deposited, spiky nanofeatured crystalline titanium (Ti surface. The variables used in the process of making the spiky Ti surface can be altered to change the physical properties of the spiky particles, and thus, the cast polymer substrate surface can be altered. The spiky Ti surface is reusable to produce additional nanopolymer castings. In this study, control plain PU and PCL polymers were produced by casting the polymers over a plain Ti surface (without spikes. All polymer surface morphologies were characterized using both scanning electron microscopy and atomic force microscopy, and their surface energies were measured using liquid contact angle measurements. The results revealed that both NPU and NPCL possessed a higher degree of nanometer surface roughness and higher surface energy compared with their respective unaltered polymers. Further, an in vitro study was carried out to determine chondrocyte (cartilage-producing cells functions on NPU and NPCL compared with on control plain polymers. Results of this study provided evidence of increased chondrocyte numbers on NPU and NPCL compared with their respective plain polymers after periods of up to 7 days. Moreover, the results provide evidence of greater intracellular protein production and collagen secretion by chondrocytes cultured on NPU and NPCL compared with control plain polymers. In summary

  14. Articular cartilage-derived cells hold a strong osteogenic differentiation potential in comparison to mesenchymal stem cells in vitro

    Energy Technology Data Exchange (ETDEWEB)

    Salamon, Achim, E-mail: achim.salamon@med.uni-rostock.de [Department of Cell Biology, Rostock University Medical Center, Schillingallee 69, D-18057 Rostock (Germany); Jonitz-Heincke, Anika, E-mail: anika.jonitz@med.uni-rostock.de [Biomechanics and Implant Technology Research Laboratory, Department of Orthopedics, Rostock University Medical Center, Doberaner Straße 142, D-18057 Rostock (Germany); Adam, Stefanie, E-mail: stefanie.adam@med.uni-rostock.de [Department of Cell Biology, Rostock University Medical Center, Schillingallee 69, D-18057 Rostock (Germany); Rychly, Joachim, E-mail: joachim.rychly@med.uni-rostock.de [Department of Cell Biology, Rostock University Medical Center, Schillingallee 69, D-18057 Rostock (Germany); Müller-Hilke, Brigitte, E-mail: brigitte.mueller-hilke@med.uni-rostock.de [Institute of Immunology, Rostock University Medical Center, Schillingallee 68, D-18057 Rostock (Germany); Bader, Rainer, E-mail: rainer.bader@med.uni-rostock.de [Biomechanics and Implant Technology Research Laboratory, Department of Orthopedics, Rostock University Medical Center, Doberaner Straße 142, D-18057 Rostock (Germany); Lochner, Katrin, E-mail: katrin.lochner@med.uni-rostock.de [Biomechanics and Implant Technology Research Laboratory, Department of Orthopedics, Rostock University Medical Center, Doberaner Straße 142, D-18057 Rostock (Germany); Peters, Kirsten, E-mail: kirsten.peters@med.uni-rostock.de [Department of Cell Biology, Rostock University Medical Center, Schillingallee 69, D-18057 Rostock (Germany)

    2013-11-01

    Cartilaginous matrix-degenerative diseases like osteoarthritis (OA) are characterized by gradual cartilage erosion, and also by increased presence of cells with mesenchymal stem cell (MSC) character within the affected tissues. Moreover, primary chondrocytes long since are known to de-differentiate in vitro and to be chondrogenically re-differentiable. Since both findings appear to conflict with each other, we quantitatively assessed the mesenchymal differentiation potential of OA patient cartilage-derived cells (CDC) towards the osteogenic and adipogenic lineage in vitro and compared it to that of MSC isolated from adipose tissue (adMSC) of healthy donors. We analyzed expression of MSC markers CD29, CD44, CD105, and CD166, and, following osteogenic and adipogenic induction in vitro, quantified their expression of osteogenic and adipogenic differentiation markers. Furthermore, CDC phenotype and proliferation were monitored. We found that CDC exhibit an MSC CD marker expression pattern similar to adMSC and a similar increase in proliferation rate during osteogenic differentiation. In contrast, the marked reduction of proliferation observed during adipogenic differentiation of adMSC was absent in CDC. Quantification of differentiation markers revealed a strong osteogenic differentiation potential for CDC, however almost no capacity for adipogenic differentiation. Since in the pathogenesis of OA, cartilage degeneration coincides with high bone turnover rates, the high osteogenic differentiation potential of OA patient-derived CDC may affect clinical therapeutic regimens aiming at autologous cartilage regeneration in these patients. - Highlights: • We analyze the mesenchymal differentiation capacity of cartilage-derived cells (CDC). • CDC express mesenchymal stem cell (MSC) markers CD29, CD44, CD105, and CD166. • CDC and MSC proliferation is reduced in adipogenesis and increased in osteogenesis. • Adipogenic differentiation is virtually absent in CDC, but

  15. Articular cartilage-derived cells hold a strong osteogenic differentiation potential in comparison to mesenchymal stem cells in vitro

    International Nuclear Information System (INIS)

    Cartilaginous matrix-degenerative diseases like osteoarthritis (OA) are characterized by gradual cartilage erosion, and also by increased presence of cells with mesenchymal stem cell (MSC) character within the affected tissues. Moreover, primary chondrocytes long since are known to de-differentiate in vitro and to be chondrogenically re-differentiable. Since both findings appear to conflict with each other, we quantitatively assessed the mesenchymal differentiation potential of OA patient cartilage-derived cells (CDC) towards the osteogenic and adipogenic lineage in vitro and compared it to that of MSC isolated from adipose tissue (adMSC) of healthy donors. We analyzed expression of MSC markers CD29, CD44, CD105, and CD166, and, following osteogenic and adipogenic induction in vitro, quantified their expression of osteogenic and adipogenic differentiation markers. Furthermore, CDC phenotype and proliferation were monitored. We found that CDC exhibit an MSC CD marker expression pattern similar to adMSC and a similar increase in proliferation rate during osteogenic differentiation. In contrast, the marked reduction of proliferation observed during adipogenic differentiation of adMSC was absent in CDC. Quantification of differentiation markers revealed a strong osteogenic differentiation potential for CDC, however almost no capacity for adipogenic differentiation. Since in the pathogenesis of OA, cartilage degeneration coincides with high bone turnover rates, the high osteogenic differentiation potential of OA patient-derived CDC may affect clinical therapeutic regimens aiming at autologous cartilage regeneration in these patients. - Highlights: • We analyze the mesenchymal differentiation capacity of cartilage-derived cells (CDC). • CDC express mesenchymal stem cell (MSC) markers CD29, CD44, CD105, and CD166. • CDC and MSC proliferation is reduced in adipogenesis and increased in osteogenesis. • Adipogenic differentiation is virtually absent in CDC, but

  16. Predicting Employee Turnover from Communication Networks.

    Science.gov (United States)

    Feeley, Thomas H.; Barnett, George A.

    1997-01-01

    Investigates three social network models of employee turnover: a structural equivalence model, a social influence model, and an erosion model. Administers a communication network questionnaire to all 170 employees of an organization. Finds support for all three models of turnover, with the erosion model explaining more of the variance than do the…

  17. Employee Turnover: An Empirical and Methodological Assessment.

    Science.gov (United States)

    Muchinsky, Paul M.; Tuttle, Mark L.

    1979-01-01

    Reviews research on the prediction of employee turnover. Groups predictor variables into five general categories: attitudinal (job satisfaction), biodata, work-related, personal, and test-score predictors. Consistent relationships between common predictor variables and turnover were found for four categories. Eight methodological problems/issues…

  18. Contextual Factors Related to Elementary Principal Turnover

    Science.gov (United States)

    Partlow, Michelle C.

    2007-01-01

    The issue of school leadership instability and how it affects schools and student achievement has been studied. The question of how to predict turnover of the principal remains an unknown. The purpose of this research was to search for possible relationships between certain contextual variables and principal turnover and to test the independent…

  19. Principal Turnover. Information Capsule. Volume 0914

    Science.gov (United States)

    Blazer, Christie

    2010-01-01

    Recent studies indicate that school districts are facing increasing rates of principal turnover. Frequent principal changes deprive schools of the leadership stability they need to succeed, disrupt long-term school reform efforts, and may even be linked to increased teacher turnover and lower levels of student achievement. This Information Capsule…

  20. Employee Turnover: Evidence from a Case Study.

    Science.gov (United States)

    Borland, Jeff

    1997-01-01

    Patterns of employee turnover from a medium-sized law firm in Australia were examined in regard to theories of worker mobility (matching, sectoral shift, and incentive). Results support a role for matching effects, but personnel practices affect the timing of turnover. Matching and incentive-based theories do not explain the high rates of turnover…

  1. The influence of collagen network integrity on the accumulation of gadolinium-based MR contrast agents in articular cartilage

    Energy Technology Data Exchange (ETDEWEB)

    Wiener, Edzard; Schmidt, C.; Diederichs, G. [Charite - Universitaetsmedizin Berlin (Germany). Inst. fuer Radiologie; Settles, M. [Klinikum rechts der Isar, Muenchen (Germany). Inst. fuer Roentgendiagnostik; Weirich, G. [Klinikum Rechts der Isar, Muenchen (Germany). Inst. fuer Pathologie und Pathologische Anatomie

    2011-03-15

    Delayed gadolinium-enhanced MR imaging of cartilage is used to quantify the proteoglycan loss in early osteoarthritis. It is assumed that T 1 after Gd-DTPA administration in the near equilibrium state reflects selective proteoglycan loss from cartilage. To investigate the influence of the collagen network integrity on contrast accumulation, the relaxation rates {delta}R1 and {delta}R2 were compared after Gd-DTPA administration in a well established model of osteoarthritis. Collagen or proteoglycan depletion was induced by the proteolytic enzymes papain and collagenase in healthy bovine patellar cartilage. Using a dedicated MRI sequence, T{sub 1} and T{sub 2} maps were simultaneously acquired before and 11 h after Gd-DTPA administration. Depth-dependent profiles of {delta}R1 and {delta}R2 were calculated in healthy, proteoglycan and collagen-depleted articular cartilage and the mean values of different cartilage layers were compared using the Mann-Whitney-U test. In superficial layers (1 mm) there was no significant difference (p > 0.05) in either {delta}R1 or {delta}R2 between proteoglycan-depleted (16.6 {+-} 1.2 s{sup -1}, 15.9 {+-} 1.0 s{sup -1}) and collagen-depleted articular cartilage (15.3 {+-} 0.9 s{sup -1}, 15.5 {+-} 0.9 s{sup -1}). In deep layers (3 mm) both parameters were significantly higher (p = 0.005, 0.03) in proteoglycan-depleted articular cartilage (12.3 {+-} 1.1 s{sup -1}, 9.8 {+-} 0.8 s{sup -1}) than in collagen-depleted articular cartilage (9.1 {+-} 1.1 s{sup -1}, 8.7 {+-} 0.7 s{sup -1}). Both proteoglycan loss and alterations in the collagen network influence the accumulation of Gd-DTPA in articular cartilage with significant differences between superficial and deep cartilage layers. (orig.)

  2. Interactive segmentation of Hip Joint Cartilage

    Czech Academy of Sciences Publication Activity Database

    Dvořák, Pavel; Juráš, V.; Vogl, W.; Chytil, J.

    Cambridge: The Electromagnetics Academy, 2014, s. 2369-2372. ISBN 978-1-934142-28-8. [PIERS 2014. Progress In Electromagnetics Research Symposium /35./. Guangzhou (CN), 25.08.2014-28.08.2014] R&D Projects: GA ČR GAP102/12/1104 Institutional support: RVO:68081731 Keywords : hip joint * MRI * segmentation of cartilage Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering

  3. Birth injuries to the epiphyseal cartilage

    International Nuclear Information System (INIS)

    A birth injury in the vicinity of a joint might lead to a fracture through the epiphyseal cartilage. The criteria for diagnosing such a fracture at radiography are considered and the continued remodelling of the bone demonstrated. The history of 2 cases with late diagnosis and serious long-term sequelae are described, in order to emphasize the necessity of early radiography. (Auth.)

  4. Spatially resolved elemental distributions in articular cartilage

    International Nuclear Information System (INIS)

    In this study, the nuclear microprobe technique is employed to analyse the chemistry of joint cartilage in order to correlate internal structures of the collagen network with the elemental distribution. The samples were taken from pig's knee joint. 30 μm thick coronar cross-sections were prepared by means of cryosectioning and freeze-drying. We performed simultaneously particle induced X-ray emission (PIXE), Rutherford backscattering spectrometry (RBS) and elastic recoil detection analysis (ERDA). Thus we obtained spatially resolved distributions of the elements H, C, N, O, P, S, Cl, K and Ca. The main components of the organic matrix are H, C, N and O. It was shown that their relations vary with the cartilage structures. It could be shown that zones with aligned collagen fibrils contain less sulphur and potassium but more chlorine. The higher chlorine concentration is remarkable because newest biochemical studies found that hypochloric acid is involved in cartilage degradation. Furthermore, the calcium distribution is still of great interest. Its correlation to structural changes inside the cartilage is still being discussed. It could be disproved that zones of higher calcium concentration are related to the aligned structures of the collagen network

  5. Advanced Strategies for Articular Cartilage Defect Repair

    Directory of Open Access Journals (Sweden)

    Fergal J. O'Brien

    2013-02-01

    Full Text Available Articular cartilage is a unique tissue owing to its ability to withstand repetitive compressive stress throughout an individual’s lifetime. However, its major limitation is the inability to heal even the most minor injuries. There still remains an inherent lack of strategies that stimulate hyaline-like articular cartilage growth with appropriate functional properties. Recent scientific advances in tissue engineering have made significant steps towards development of constructs for articular cartilage repair. In particular, research has shown the potential of biomaterial physico-chemical properties significantly influencing the proliferation, differentiation and matrix deposition by progenitor cells. Accordingly, this highlights the potential of using such properties to direct the lineage towards which such cells follow. Moreover, the use of soluble growth factors to enhance the bioactivity and regenerative capacity of biomaterials has recently been adopted by researchers in the field of tissue engineering. In addition, gene therapy is a growing area that has found noteworthy use in tissue engineering partly due to the potential to overcome some drawbacks associated with current growth factor delivery systems. In this context, such advanced strategies in biomaterial science, cell-based and growth factor-based therapies that have been employed in the restoration and repair of damaged articular cartilage will be the focus of this review article.

  6. Zn deposition at the bone cartilage interface in equine articular cartilage

    Science.gov (United States)

    Bradley, D. A.; Moger, C. J.; Winlove, C. P.

    2007-09-01

    In articular cartilage metalloproteinases, a family of enzymes whose function relies on the presence of divalent cations such as Zn and Ca plays a central role in the normal processes of growth and remodelling and in the degenerative and inflammatory processes of arthritis. Another important enzyme, alkaline phosphatase, involved in cartilage mineralisation also relies on metallic cofactors. The local concentration of divalent cations is therefore of considerable interest in cartilage pathophysiology and several authors have used synchrotron X-ray fluorescence (XRF) to map metal ion distributions in bone and cartilage. We report use of a bench-top XRF analytical microscope, providing spatial resolution of 10 μm and applicable to histological sections, facilitating correlation of the distribution with structural features. The study seeks to establish the elemental distribution in normal tissue as a precursor to investigation of changes in disease. For six samples prepared from equine metacarpophalangeal joint, we observed increased concentration of Zn and Sr ions around the tidemark between normal and mineralised cartilage. This is believed to be an active site of remodelling but its composition has hitherto lacked detailed characterization. We also report preliminary results on two of the samples using Proton-Induced X-ray Emission (PIXE). This confirms our previous observations using synchrotron-based XRF of enhanced deposition of Sr and Zn at the surface of the subchondral bone and in articular cartilage.

  7. Zn deposition at the bone-cartilage interface in equine articular cartilage

    Energy Technology Data Exchange (ETDEWEB)

    Bradley, D.A. [Department of Physics, University of Surrey, Guildford, GU2 7XH (United Kingdom)], E-mail: D.A.Bradley@surrey.ac.uk; Moger, C.J.; Winlove, C.P. [School of Physics, University of Exeter, Exeter, EX4 4QL (United Kingdom)

    2007-09-21

    In articular cartilage metalloproteinases, a family of enzymes whose function relies on the presence of divalent cations such as Zn and Ca plays a central role in the normal processes of growth and remodelling and in the degenerative and inflammatory processes of arthritis. Another important enzyme, alkaline phosphatase, involved in cartilage mineralisation also relies on metallic cofactors. The local concentration of divalent cations is therefore of considerable interest in cartilage pathophysiology and several authors have used synchrotron X-ray fluorescence (XRF) to map metal ion distributions in bone and cartilage. We report use of a bench-top XRF analytical microscope, providing spatial resolution of 10 {mu}m and applicable to histological sections, facilitating correlation of the distribution with structural features. The study seeks to establish the elemental distribution in normal tissue as a precursor to investigation of changes in disease. For six samples prepared from equine metacarpophalangeal joint, we observed increased concentration of Zn and Sr ions around the tidemark between normal and mineralised cartilage. This is believed to be an active site of remodelling but its composition has hitherto lacked detailed characterization. We also report preliminary results on two of the samples using Proton-Induced X-ray Emission (PIXE). This confirms our previous observations using synchrotron-based XRF of enhanced deposition of Sr and Zn at the surface of the subchondral bone and in articular cartilage.

  8. Zn deposition at the bone-cartilage interface in equine articular cartilage

    International Nuclear Information System (INIS)

    In articular cartilage metalloproteinases, a family of enzymes whose function relies on the presence of divalent cations such as Zn and Ca plays a central role in the normal processes of growth and remodelling and in the degenerative and inflammatory processes of arthritis. Another important enzyme, alkaline phosphatase, involved in cartilage mineralisation also relies on metallic cofactors. The local concentration of divalent cations is therefore of considerable interest in cartilage pathophysiology and several authors have used synchrotron X-ray fluorescence (XRF) to map metal ion distributions in bone and cartilage. We report use of a bench-top XRF analytical microscope, providing spatial resolution of 10 μm and applicable to histological sections, facilitating correlation of the distribution with structural features. The study seeks to establish the elemental distribution in normal tissue as a precursor to investigation of changes in disease. For six samples prepared from equine metacarpophalangeal joint, we observed increased concentration of Zn and Sr ions around the tidemark between normal and mineralised cartilage. This is believed to be an active site of remodelling but its composition has hitherto lacked detailed characterization. We also report preliminary results on two of the samples using Proton-Induced X-ray Emission (PIXE). This confirms our previous observations using synchrotron-based XRF of enhanced deposition of Sr and Zn at the surface of the subchondral bone and in articular cartilage

  9. Chronic Teacher Turnover in Urban Elementary Schools

    Directory of Open Access Journals (Sweden)

    Kacey Guin

    2004-08-01

    Full Text Available This study examines the characteristics of elementary schools that experience chronic teacher turnover and the impacts of turnover on a school’s working climate and ability to effectively function. Based on evidence from staff climate surveys and case studies, it is clear that high turnover schools face significant organizational challenges. Schools with high teacher turnover rates have difficulty planning and implementing a coherent curriculum and sustaining positive working relationships among teachers. The reality of these organizational challenges is particularly alarming, given that high turnover schools are more likely to serve low-income and minority students. The negative relationship between teacher turnover and school functioning, and the fact that turbulent schools are disproportionately likely to serve lowincome and minority students have important implications for both district and school-level policies. Specifically: Teacher turnover rates are one indicator of school health, which school districts should consider when focusing on school improvements. Districts need to begin by developing the means to identify individual schools that experience high levels of teacher turnover. Current district policies in implementing professional development for teachers in low-performing schools are inefficient when teachers do not remain in the schools in which they are trained. In order for low-performing schools to improve, districts need to consider providing incentive programs so that high quality teachers apply for, and remain in, these schools. Future research is needed to address the causal link between turnover, organizational functioning and student outcomes. Additionally, there is a need for research examining district policies that may facilitate teacher turnover within a district, including how districts place and transfer teachers, as well as how teachers’ salaries are budgeted.

  10. System turnover and acceptance procedure of Qingshan NPP

    International Nuclear Information System (INIS)

    Turnover and acceptance process of nuclear power plant has direct influence on construction scheduling. The authors describe organization, conditions and implementation of system turnover and acceptance. The paper also gives some suggestions as reference of turnover and acceptance work

  11. Turnover intention in new graduate nurses: a multivariate analysis

    OpenAIRE

    Beecroft, Pauline C; Dorey, Frederick; Wenten, Madé

    2008-01-01

    Title Turnover intention in new graduate nurses: a multivariate analysis Aim This paper is a report of a study to determine the relationship of new nurse turnover intent with individual characteristics, work environment variables and organizational factors and to compare new nurse turnover with actual turnover in the 18 months of employment following completion of a residency. Background Because of their influence on patient safety and health outcomes nurse turnover and turnover intent have r...

  12. The Research Progress and Prospect of Employee Turnover Intention

    OpenAIRE

    Somchit Hongvichit

    2015-01-01

    Employee turnover management is an important aspect of human resource management, how to effectively control and predict employee turnover becomes an important content of academic research. Related research results show that the turnover intention is employee turnover behavior of the most direct antecedents, can predict employee turnover behavior. The author reviews the employee turnover intention, the connotation of the antecedent variables and measurement, the future trend of development an...

  13. Freeze-thaw treatment effects on the dynamic mechanical properties of articular cartilage

    Directory of Open Access Journals (Sweden)

    Muldrew Ken

    2010-10-01

    Full Text Available Abstract Background As a relatively non-regenerative tissue, articular cartilage has been targeted for cryopreservation as a method of mitigating a lack of donor tissue availability for transplant surgeries. In addition, subzero storage of articular cartilage has long been used in biomedical studies using various storage temperatures. The current investigation studies the potential for freeze-thaw to affect the mechanical properties of articular cartilage through direct comparison of various subzero storage temperatures. Methods Both subzero storage temperature as well as freezing rate were compared using control samples (4°C and samples stored at either -20°C or -80°C as well as samples first snap frozen in liquid nitrogen (-196°C prior to storage at -80°C. All samples were thawed at 37.5°C to testing temperature (22°C. Complex stiffness and hysteresis characterized load resistance and damping properties using a non-destructive, low force magnitude, dynamic indentation protocol spanning a broad loading rate range to identify the dynamic viscoelastic properties of cartilage. Results Stiffness levels remained unchanged with exposure to the various subzero temperatures. Hysteresis increased in samples snap frozen at -196°C and stored at -80°C, though remained unchanged with exposure to the other storage temperatures. Conclusions Mechanical changes shown are likely due to ice lens creation, where frost heave effects may have caused collagen damage. That storage to -20°C and -80°C did not alter the mechanical properties of articular cartilage shows that when combined with a rapid thawing protocol to 37.5°C, the tissue may successfully be stored at subzero temperatures.

  14. Chemical changes demonstrated in cartilage by synchrotron infrared microspectroscopy in an antibody-induced murine model of rheumatoid arthritis

    Science.gov (United States)

    Croxford, Allyson M.; Selva Nandakumar, Kutty; Holmdahl, Rikard; Tobin, Mark J.; McNaughton, Don; Rowley, Merrill J.

    2011-06-01

    Collagen antibody-induced arthritis develops in mice following passive transfer of monoclonal antibodies (mAbs) to type II collagen (CII) and is attributed to effects of proinflammatory immune complexes, but transferred mAbs may react directly and damagingly with CII. To determine whether such mAbs cause cartilage damage in vivo in the absence of inflammation, mice lacking complement factor 5 that do not develop joint inflammation were injected intravenously with two arthritogenic mAbs to CII, M2139 and CIIC1. Paws were collected at day 3, decalcified, paraffin embedded, and 5-μm sections were examined using standard histology and synchrotron Fourier-transform infrared microspectroscopy (FTIRM). None of the mice injected with mAb showed visual or histological evidence of inflammation but there were histological changes in the articular cartilage including loss of proteoglycan and altered chondrocyte morphology. Findings using FTIRM at high lateral resolution revealed loss of collagen and the appearance of a new peak at 1635 cm-1 at the surface of the cartilage interpreted as cellular activation. Thus, we demonstrate the utility of synchrotron FTIRM for examining chemical changes in diseased cartilage at the microscopic level and establish that arthritogenic mAbs to CII do cause cartilage damage in vivo in the absence of inflammation.

  15. Rapid Cellular Turnover in Adipose Tissue

    OpenAIRE

    Alessandra Rigamonti; Kristen Brennand; Frank Lau; Cowan, Chad A.

    2011-01-01

    It was recently shown that cellular turnover occurs within the human adipocyte population. Through three independent experimental approaches — dilution of an inducible histone 2B-green fluorescent protein (H2BGFP), labeling with the cell cycle marker Ki67 and incorporation of BrdU — we characterized the degree of cellular turnover in murine adipose tissue. We observed rapid turnover of the adipocyte population, finding that 4.8% of preadipocytes are replicating at any time and that between 1–...

  16. The validation of the turnover intention scale

    Directory of Open Access Journals (Sweden)

    Chris F.C. Bothma

    2013-01-01

    Full Text Available Orientation: Turnover intention as a construct has attracted increased research attention in the recent past, but there are seemingly not many valid and reliable scales around to measure turnover intention.Research purpose: This study focused on the validation of a shortened, six-item version of the turnover intention scale (TIS-6.Motivation for the study: The research question of whether the TIS-6 is a reliable and a valid scale for measuring turnover intention and for predicting actual turnover was addressed in this study.Research design, approach and method: The study was based on a census-based sample (n= 2429 of employees in an information, communication and technology (ICT sector company (N= 23 134 where the TIS-6 was used as one of the criterion variables. The leavers (those who left the company in this sample were compared with the stayers (those who remained in the employ of the company in this sample in respect of different variables used in the study.Main findings: It was established that the TIS-6 could measure turnover intentions reliably (α= 0.80. The TIS-6 could significantly distinguish between leavers and stayers (actual turnover, thereby confirming its criterion-predictive validity. The scale also established statistically significant differences between leavers and stayers in respect of a number of the remaining theoretical variables used in the study, thereby also confirming its differential validity. These comparisons were conducted for both the 4-month and the 4-year period after the survey was conducted.Practical/managerial implications: Turnover intention is related to a number of variables in the study which necessitates a reappraisal and a reconceptualisation of existing turnover intention models.Contribution/value-add: The TIS-6 can be used as a reliable and valid scale to assess turnover intentions and can therefore be used in research to validly and reliably assess turnover intentions or to

  17. Improvements to Kramers Turnover Theory

    CERN Document Server

    Pollak, Eli

    2013-01-01

    The Kramers turnover problem, that is obtaining a uniform expression for the rate of escape of a particle over a barrier for any value of the external friction was solved in the eighties. Two formulations were given, one by Melnikov and Meshkov (MM) (J. Chem. Phys. 85, 1018 (1986)), which was based on a perturbation expansion for the motion of the particle in the presence of friction. The other, by Pollak, Grabert and Haenggi (PGH) (J. Chem. Phys. 91, 4073 (1989)), valid also for memory friction, was based on a perturbation expansion for the motion along the collective unstable normal mode of the particle. Both theories did not take into account the temperature dependence of the average energy loss to the bath. Increasing the bath temperature will reduce the average energy loss. In this paper, we analyse this effect, using a novel perturbation theory. We find that within the MM approach, the thermal energy gained from the bath diverges, the average energy gain becomes infinite, implying an essential failure o...

  18. Serum cartilage oligomeric matrix protein (COMP) decreases in rheumatoid arthritis patients treated with infliximab or etanercept

    Science.gov (United States)

    Crnkic, Meliha; Månsson, Bengt; Larsson, Lotta; Geborek, Pierre; Heinegård, Dick; Saxne, Tore

    2003-01-01

    Changes in serum cartilage oligomeric matrix protein (COMP) were studied during a 6-month period from initiation of treatment of rheumatoid arthritis patients with either infliximab or etanercept, to elucidate whether the favourable results of tissue protection reported in clinical trials are corroborated by changing levels of circulating COMP. Rheumatoid arthritis patients commencing treatment with infliximab (N = 32) or etanercept (N = 17) were monitored in accordance with a structured protocol. Only patients who were not receiving glucocorticoids or who were on a stable dose of oral prednisolone (<10 mg daily) were included. Serum COMP was measured by a sandwich immunoassay based on two monoclonal antibodies against human COMP in samples obtained at treatment initiation and at 3 and 6 months. Serum COMP decreased at 3 months in both infliximab- and etanercept-treated patients (P < 0.001 and <0.005, respectively) and remained low at 6 months. There was no significant correlation between changes in or concentrations of serum COMP and serum C-reactive protein at any time point. A decrease in serum COMP was seen both in ACR20 responders (patients meeting the American College of Rheumatology criteria for 20% improvement) and in nonresponders. The pattern of changes of serum COMP, a marker for cartilage turnover, in these patient groups supports the interpretation that infliximab and etanercept have a joint protective effect. Serum COMP has potential as a useful marker for evaluating tissue effects of novel treatment modalities in rheumatoid arthritis. PMID:12823852

  19. The effects of femoral graft placement on cartilage thickness after anterior cruciate ligament reconstruction.

    Science.gov (United States)

    Okafor, Eziamaka C; Utturkar, Gangadhar M; Widmyer, Margaret R; Abebe, Ermias S; Collins, Amber T; Taylor, Dean C; Spritzer, Charles E; Moorman, C T; Garrett, William E; DeFrate, Louis E

    2014-01-01

    Altered joint motion has been thought to be a contributing factor in the long-term development of osteoarthritis after ACL reconstruction. While many studies have quantified knee kinematics after ACL injury and reconstruction, there is limited in vivo data characterizing the effects of altered knee motion on cartilage thickness distributions. Thus, the objective of this study was to compare cartilage thickness distributions in two groups of patients with ACL reconstruction: one group in which subjects received a non-anatomic reconstruction that resulted in abnormal joint motion and another group in which subjects received an anatomically placed graft that more closely restored normal knee motion. Ten patients with anatomic graft placement (mean follow-up: 20 months) and 12 patients with non-anatomic graft placement (mean follow-up: 18 months) were scanned using high-resolution MR imaging. These images were used to generate 3D mesh models of both knees of each patient. The operative and contralateral knee models were registered to each other and a grid sampling system was used to make site-specific comparisons of cartilage thickness. Patients in the non-anatomic graft placement group demonstrated a significant decrease in cartilage thickness along the medial intercondylar notch in the operative knee relative to the intact knee (8%). In the anatomic graft placement group, no significant changes were observed. These findings suggest that restoring normal knee motion after ACL injury may help to slow the progression of degeneration. Therefore, graft placement may have important implications on the development of osteoarthritis after ACL reconstruction. PMID:24210473

  20. Dietary 2-oxoglutarate mitigates gastrectomy-evoked structural changes in cartilage of female rats.

    Science.gov (United States)

    Dobrowolski, Piotr; Tomaszewska, Ewa; Kurlak, Paulina; Pierzynowski, Stefan G

    2016-01-01

    Gastrectomy (Gx) leads to osteopenia/osteoporosis in humans and animals. However, little is known about the influence of Gx on the cartilage in this regard. Recent studies have demonstrated a protective effect of 2-oxoglutaric acid (2-Ox) on bone and cartilage. Hence, the purpose of this study was to investigate whether 2-Ox can mitigate eventual Gx-induced cartilage impairment. Twenty female Sprague-Dawley rats were subjected to Gx and randomly divided into two groups: Gx + 2-Ox and Gx. Another 20 rats were sham-operated (ShO) and randomly divided into two groups: ShO + 2-Ox and ShO. The daily dose of 2-Ox administered to the rats in the drinking water was 0.43 g per 100 g rat. After eight weeks, rats were euthanized and femora and tibiae were collected. Histology and histomorphometry analyses of the articular cartilage and the growth plate were done. Gx resulted in a 32% (±44.5 femur, ±35.8 tibia) decrease in overall thickness of articular cartilage in both bones (femur: ShO 279.1 ± 48.5 vs. Gx 190.2 ± 38.4 µm, tibia: ShO 222.9 ± 50.3 µm vs. Gx 151.3 ± 52.6 µm) (in some zones up to 58 ± 28.0%), and in the growth plate up to 20% (±22.4) (femur: ShO 243.0 ± 34.0 vs. Gx 207.0 ± 33.7 µm, tibia: ShO 220.0 ± 24.6 µm vs. Gx 171.1 ± 16.1 µm). Gx altered the spatial distribution of thick and thin collagen fibers, and chondrocyte shape and size. 2-Ox administration prevented the reduction in both cartilages thickness (Gx + 2-Ox: articular cartilage 265.2 ± 53.8 µm, 235.6 ± 42.7 µm, growth plate 236.7 ± 39.2 µm, 191.3 ± 16.5 µm in femur and tibia, respectively), and abolished the spatial changes in collagen distribution and structure induced by Gx. Gx affects cartilage structure and thickness, however, 2-Ox administration mitigates these effects and showed protective and stimulatory properties. Our observations suggest that dietary 2-Ox can be used to offset

  1. Analysis of friction between articular cartilage and polyvinyl alcohol hydrogel artificial cartilage.

    Science.gov (United States)

    Li, Feng; Wang, Anmin; Wang, Chengtao

    2016-05-01

    Many biomaterials are being used to repair damaged articular cartilage. In particular, poly vinyl alcohol hydrogel has similar mechanical properties to natural cartilage under compressive and shearing loading. Here, three-factor and two-level friction experiments and long-term tests were conducted to better evaluate its tribological properties. The friction coefficient between articular cartilage and the poly vinyl alcohol hydrogel depended primarily on the three factors of load, speed, and lubrication. When the speed increased from 10 to 20 mm/s under a load of 10 N, the friction coefficient increased from 0.12 to 0.147. When the lubricant was changed from Ringer's solution to a hyaluronic acid solution, the friction coefficient decreased to 0.084 with loads as high as 22 N. The poly vinyl alcohol hydrogel was severely damaged and lost its top surface layers, which were transferred to the articular cartilage surface. Wear was observed in the surface morphologies, which indicated the occurrence of surface adhesion of bovine cartilage. Surface fatigue and adhesive wear was the dominant wear mechanism. PMID:26970769

  2. Alpha-synuclein gene ablation increases docosahexaenoic acid incorporation and turnover in brain phospholipids

    DEFF Research Database (Denmark)

    Golovko, Mikhail Y; Rosenberger, Thad A; Feddersen, Søren;

    2007-01-01

    incorporation rate and turnover in ethanolamine glycerophospholipid, phosphatidylserine, and phosphatidylinositol pools. Increased 22:6n-3-CoA mass was not the result of altered Acsl activity, which was unaffected by the absence of Snca. While Snca bound 22:6n-3, Kd = 1.0 +/- 0.5 micromol/L, it did not bind 22......Previously, we demonstrated that ablation of alpha-synuclein (Snca) reduces arachidonate (20:4n-6) turnover in brain phospholipids through modulation of an endoplasmic reticulum-localized acyl-CoA synthetase (Acsl). The effect of Snca ablation on docosahexaenoic acid (22:6n-3) metabolism is unknown...

  3. Biomimetic catalysis: Taking on the turnover challenge

    Science.gov (United States)

    Hooley, Richard J.

    2016-03-01

    Emulating the efficiency with which enzymes catalyse reactions has often been used as inspiration to develop self-assembled cages. Now two studies present approaches to achieving catalyst turnover -- one of the biggest challenges in achieving truly biomimetic catalysis.

  4. THEORETICAL ASPECTS REGARDING THE TURNOVER ANALYSIS

    Directory of Open Access Journals (Sweden)

    CARUNTU ROXANA CORINA

    2011-09-01

    Full Text Available Nowadays, when the economic crisis seems not to be overcome by the authorities it is important for companies to see how they are performing, if their products are sold or not and if it is necessary to take measures according to the results obtained. The turnover expresses the total revenues obtained by a company from its current commercial activities, being one of the most important indicators of measuring the performance of the company. The aim of this paper is to stress the theoretical implications that turnover has over the economic activity of a company. In the chapters of the paper we will present theoretical notions regarding the concept of turnover analysis, meaning analysis of the turnover’s dynamics, the structural analysis of turnover.

  5. Cartilage restoration technique of the hip.

    Science.gov (United States)

    Mardones, Rodrigo; Larrain, Catalina

    2016-04-01

    Hip cartilage lesions represent a diagnostic challenge and can be an elusive source of pain. Treatment may present difficulties due to localization and spherical form of the joint and is most commonly limited to excision, debridement, thermal chondroplasty and microfractures. This chapter will focus in new technologies to enhance the standard techniques. These new technologies are based in stem cells therapies; as intra-articular injections of expanded mesenchymal stem cells, mononuclear concentrate in a platelet-rich plasma matrix and expanded mesenchymal stem cells seeded in a collagen membrane. This review will discuss the bases, techniques and preliminary results obtained with the use of stem cells for the treatment of hip cartilage lesions. PMID:27026816

  6. Bioprinted Scaffolds for Cartilage Tissue Engineering.

    Science.gov (United States)

    Kang, Hyun-Wook; Yoo, James J; Atala, Anthony

    2015-01-01

    Researchers are focusing on bioprinting technology as a viable option to overcome current difficulties in cartilage tissue engineering. Bioprinting enables a three-dimensional (3-D), free-form, computer-designed structure using biomaterials, biomolecules, and/or cells. The inner and outer shape of a scaffold can be controlled by this technology with great precision. Here, we introduce a hybrid bioprinting technology that is a co-printing process of multiple materials including high-strength synthetic polymer and cell-laden hydrogel. The synthetic polymer provides mechanical support for shape maintenance and load bearing, while the hydrogel provides the biological environment for artificial cartilage regeneration. This chapter introduces the procedures for printing of a 3-D scaffold using our hybrid bioprinting technology and includes the source materials for preparation of 3-D printing. PMID:26445837

  7. Impact of motivation principles on employee turnover

    OpenAIRE

    VNOUČKOVÁ, Lucie; Klupáková, Hana

    2013-01-01

    The article focuses on the analysis of motivation principles in human resource management and their further verification by factor analysis. The objective is to identify the main motivation principles and their impacts on employee turnover as well as formulate suggested practices to eliminate the negative impact of employee disaffection and turnover. The identification of motivation principles is based on a content analysis of professional and scientific publications aimed at moti...

  8. Plant Turnover and Structural Reforms in Colombia

    OpenAIRE

    Marcela Eslava; John Haltiwanger; Adriana Kugler; Maurice Kugler

    2006-01-01

    In a healthy economy, plant turnover increases aggregate productivity because efficient producers are more likely to survive. Given high entry and exit rates and the potential importance of turnover in accounting for aggregate productivity, in this paper we examine the determinants of plant exits and then examine how exits and other forms of output reallocation contribute to aggregate productivity. Using a unique plant-level longitudinal data set for Colombia for the period 1982-98, we examin...

  9. Turnover Costs, Efficiency Wages and Cycles

    OpenAIRE

    W. Bentley MacLeod; Malcomson, James M.

    1995-01-01

    This paper studies the implications of our recent work on two labour market imperfections for the cyclical properties of wages and employment. One of these imperfections is turnover costs. We explore the implications of the interaction of turnover costs with investment decisions for the form of wage contracts and hence for the cyclical properties of wages. The other imperfection is the difficulty of verifying employee performance. We consider the implications of this for the payment of effici...

  10. "Labor Turnover and Labor Legislation in Brazil"

    OpenAIRE

    Gustavo Gonzaga

    2003-01-01

    One of the main characteristics of the Brazilian labor market is its impressively high job and worker turnover rates. Although labor legislation in Brazil is very restrictive, dismissal costs are not high when compared with other Latin American countries. Moreover, many authors argue that the design of some job security programs creates perverse incentives that generate labor turnover. The objective of this paper is twofold. First, we describe Brazilian labor legislation, with emphasis on job...

  11. Labor Turnover and Labor Legislation in Brazil

    OpenAIRE

    Gustavo Gonzaga

    2003-01-01

    One of the main characteristics of the Brazilian labor market is its impressively high job and worker turnover rates. Although labor legislation in Brazil is very restrictive, dismissal costs are not high when compared with other Latin American countries. Moreover, many authors argue that the design of some job security programs creates perverse incentives that generate labor turnover. The objective of this paper is twofold. First, we describe Brazilian labor legislation, with emphasis on job...

  12. Time-Dependent Nanomechanics of Cartilage

    OpenAIRE

    Han, Lin; Frank, Eliot H.; Greene, Jacqueline J.; Lee, Hsu-Yi; Hung, Han-Hwa K.; Grodzinsky, Alan J.; Ortiz, Christine

    2011-01-01

    In this study, atomic force microscopy-based dynamic oscillatory and force-relaxation indentation was employed to quantify the time-dependent nanomechanics of native (untreated) and proteoglycan (PG)-depleted cartilage disks, including indentation modulus Eind, force-relaxation time constant τ, magnitude of dynamic complex modulus |E∗|, phase angle δ between force and indentation depth, storage modulus E′, and loss modulus E″. At ∼2 nm dynamic deformation amplitude, |E∗| increased significant...

  13. Cartilage restoration technique of the hip

    OpenAIRE

    Mardones, Rodrigo; Larrain, Catalina

    2015-01-01

    Hip cartilage lesions represent a diagnostic challenge and can be an elusive source of pain. Treatment may present difficulties due to localization and spherical form of the joint and is most commonly limited to excision, debridement, thermal chondroplasty and microfractures. This chapter will focus in new technologies to enhance the standard techniques. These new technologies are based in stem cells therapies; as intra-articular injections of expanded mesenchymal stem cells, mononuclear conc...

  14. Oxygen, nitric oxide and articular cartilage

    OpenAIRE

    Fermor, B.; Christensen, S. E.; I Youn; J M Cernanec; C M Davies; Weinberg, J. B.

    2007-01-01

    Molecular oxygen is required for the production of nitric oxide (NO), a pro-inflammatory mediator that is associated with osteoarthritis and rheumatoid arthritis. To date there has been little consideration of the role of oxygen tension in the regulation of nitric oxide production associated with arthritis. Oxygen tension may be particularly relevant to articular cartilage since it is avascular and therefore exists at a reduced oxygen tension. The superficial zone exists at approximately 6% O...

  15. Articular cartilage collagen: an irreplaceable framework?

    OpenAIRE

    Eyre, D. R.; Weis, M A; J-J Wu

    2006-01-01

    Adult articular cartilage by dry weight is two-thirds collagen. The collagen has a unique molecular phenotype. The nascent type II collagen fibril is a heteropolymer, with collagen IX molecules covalently linked to the surface and collagen XI forming the filamentous template of the fibril as a whole. The functions of collagens IX and XI in the heteropolymer are far from clear but, evidently, they are critically important since mutations in COLIX and COLXI genes can result in chondrodysplasia ...

  16. Cartilage Tissue Engineering: What Have We Learned in Practice?

    Science.gov (United States)

    Doran, Pauline M

    2015-01-01

    Many technologies that underpin tissue engineering as a research field were developed with the aim of producing functional human cartilage in vitro. Much of our practical experience with three-dimensional cultures, tissue bioreactors, scaffold materials, stem cells, and differentiation protocols was gained using cartilage as a model system. Despite these advances, however, generation of engineered cartilage matrix with the composition, structure, and mechanical properties of mature articular cartilage has not yet been achieved. Currently, the major obstacles to synthesis of clinically useful cartilage constructs are our inability to control differentiation to the extent needed, and the failure of engineered and host tissues to integrate after construct implantation. The aim of this chapter is to distil from the large available body of literature the seminal approaches and experimental techniques developed for cartilage tissue engineering and to identify those specific areas requiring further research effort. PMID:26445827

  17. Processed bovine cartilage: an improved biosynthetic implant for contour defects

    Energy Technology Data Exchange (ETDEWEB)

    Ersek, R.A.; Hart, W.G. Jr.; Greer, D.; Beisang, A.A.; Flynn, P.J.; Denton, D.R.

    1984-05-01

    Irradiated human cartilage has been found to be a superior implant material for correction of contour defects; however, availability problems have prevented this material from gaining wide acceptance. Implantation of processed irradiated bovine cartilage in primates and rabbits, as described here, provides strong evidence that this material performs like irradiated allograft cartilage antigenically and has certain cosmetic advantages over allograft cartilage. Our studies in primates have shown that there is no systemically measurable antibody-antigen reaction, either cellular or noncellular, to irradiated processed bovine cartilage. Neither primary nor second-set provocative implantations produced any measurable rejection. In rabbits, composite grafts of two pieces of irradiated bovine cartilage adjacent to each other were also well tolerated, with no measurable absorption and with capsule formation typical of a foreign body reaction to an inert object.

  18. Time-dependent nanomechanics of cartilage.

    Science.gov (United States)

    Han, Lin; Frank, Eliot H; Greene, Jacqueline J; Lee, Hsu-Yi; Hung, Han-Hwa K; Grodzinsky, Alan J; Ortiz, Christine

    2011-04-01

    In this study, atomic force microscopy-based dynamic oscillatory and force-relaxation indentation was employed to quantify the time-dependent nanomechanics of native (untreated) and proteoglycan (PG)-depleted cartilage disks, including indentation modulus E(ind), force-relaxation time constant τ, magnitude of dynamic complex modulus |E(∗)|, phase angle δ between force and indentation depth, storage modulus E', and loss modulus E″. At ∼2 nm dynamic deformation amplitude, |E(∗)| increased significantly with frequency from 0.22 ± 0.02 MPa (1 Hz) to 0.77 ± 0.10 MPa (316 Hz), accompanied by an increase in δ (energy dissipation). At this length scale, the energy dissipation mechanisms were deconvoluted: the dynamic frequency dependence was primarily governed by the fluid-flow-induced poroelasticity, whereas the long-time force relaxation reflected flow-independent viscoelasticity. After PG depletion, the change in the frequency response of |E(∗)| and δ was consistent with an increase in cartilage local hydraulic permeability. Although untreated disks showed only slight dynamic amplitude-dependent behavior, PG-depleted disks showed great amplitude-enhanced energy dissipation, possibly due to additional viscoelastic mechanisms. Hence, in addition to functioning as a primary determinant of cartilage compressive stiffness and hydraulic permeability, the presence of aggrecan minimized the amplitude dependence of |E(∗)| at nanometer-scale deformation. PMID:21463599

  19. Irradiated homologous costal cartilage for augmentation rhinoplasty

    Energy Technology Data Exchange (ETDEWEB)

    Lefkovits, G. (Lenox Hill Hospital, New York, NY (USA))

    1990-10-01

    Although the ideal reconstructive material for augmentation rhinoplasty continues to challenge plastic surgeons, there exists no report in the literature that confines the use of irradiated homologous costal cartilage, first reported by Dingman and Grabb in 1961, to dorsal nasal augmentation. The purpose of this paper is to present a retrospective analysis of the author's experience using irradiated homologous costal cartilage in augmentation rhinoplasty. Twenty-seven dorsal nasal augmentations were performed in 24 patients between 16 and 49 years of age with a follow-up ranging from 1 to 27 months. Good-to-excellent results were achieved in 83.3% (20 of 24). Poor results requiring revision were found in 16.7% (4 of 24). Complication rates included 7.4% infection (2 of 27) and 14.8% warping (4 of 27). The resorption rate was zero. These results compare favorably with other forms of nasal augmentation. Advantages and disadvantages of irradiated homologous costal cartilage are discussed.

  20. Cartilage-Specific Near-Infrared Fluorophores for Biomedical Imaging.

    Science.gov (United States)

    Hyun, Hoon; Owens, Eric A; Wada, Hideyuki; Levitz, Andrew; Park, GwangLi; Park, Min Ho; Frangioni, John V; Henary, Maged; Choi, Hak Soo

    2015-07-20

    A novel class of near-infrared fluorescent contrast agents was developed. These agents target cartilage with high specificity and this property is inherent to the chemical structure of the fluorophore. After a single low-dose intravenous injection and a clearance time of approximately 4 h, these agents bind to all three major types of cartilage (hyaline, elastic, and fibrocartilage) and perform equally well across species. Analysis of the chemical structure similarities revealed a potential pharmacophore for cartilage targeting. Our results lay the foundation for future improvements in tissue engineering, joint surgery, and cartilage-specific drug development. PMID:26095685

  1. Cutaneous Squamous Cell Carcinoma with Invasion through Ear Cartilage

    Directory of Open Access Journals (Sweden)

    Julie Boisen

    2016-01-01

    Full Text Available Cutaneous squamous cell carcinoma of the ear represents a high-risk tumor location with an increased risk of metastasis and local tissue invasion. However, it is uncommon for these cancers to invade through nearby cartilage. Cartilage invasion is facilitated by matrix metalloproteases, specifically collagenase 3. We present the unusual case of a 76-year-old man with an auricular squamous cell carcinoma that exhibited full-thickness perforation of the scapha cartilage. Permanent sections through the eroded cartilage confirmed tumor invasion extending to the posterior ear skin.

  2. Secondary cartilage revealed in a non-avian dinosaur embryo.

    Science.gov (United States)

    Bailleul, Alida M; Hall, Brian K; Horner, John R

    2013-01-01

    The skull and jaws of extant birds possess secondary cartilage, a tissue that arises after bone formation during embryonic development at articulations, ligamentous and muscular insertions. Using histological analysis, we discovered secondary cartilage in a non-avian dinosaur embryo, Hypacrosaurus stebingeri (Ornithischia, Lambeosaurinae). This finding extends our previous report of secondary cartilage in post-hatching specimens of the same dinosaur species. It provides the first information on the ontogeny of avian and dinosaurian secondary cartilages, and further stresses their developmental similarities. Secondary cartilage was found in an embryonic dentary within a tooth socket where it is hypothesized to have arisen due to mechanical stresses generated during tooth formation. Two patterns were discerned: secondary cartilage is more restricted in location in this Hypacrosaurus embryo, than it is in Hypacrosaurus post-hatchlings; secondary cartilage occurs at far more sites in bird embryos and nestlings than in Hypacrosaurus. This suggests an increase in the number of sites of secondary cartilage during the evolution of birds. We hypothesize that secondary cartilage provided advantages in the fine manipulation of food and was selected over other types of tissues/articulations during the evolution of the highly specialized avian beak from the jaws of their dinosaurian ancestors. PMID:23418610

  3. Secondary cartilage revealed in a non-avian dinosaur embryo.

    Directory of Open Access Journals (Sweden)

    Alida M Bailleul

    Full Text Available The skull and jaws of extant birds possess secondary cartilage, a tissue that arises after bone formation during embryonic development at articulations, ligamentous and muscular insertions. Using histological analysis, we discovered secondary cartilage in a non-avian dinosaur embryo, Hypacrosaurus stebingeri (Ornithischia, Lambeosaurinae. This finding extends our previous report of secondary cartilage in post-hatching specimens of the same dinosaur species. It provides the first information on the ontogeny of avian and dinosaurian secondary cartilages, and further stresses their developmental similarities. Secondary cartilage was found in an embryonic dentary within a tooth socket where it is hypothesized to have arisen due to mechanical stresses generated during tooth formation. Two patterns were discerned: secondary cartilage is more restricted in location in this Hypacrosaurus embryo, than it is in Hypacrosaurus post-hatchlings; secondary cartilage occurs at far more sites in bird embryos and nestlings than in Hypacrosaurus. This suggests an increase in the number of sites of secondary cartilage during the evolution of birds. We hypothesize that secondary cartilage provided advantages in the fine manipulation of food and was selected over other types of tissues/articulations during the evolution of the highly specialized avian beak from the jaws of their dinosaurian ancestors.

  4. IL-1 beta and TGF-beta 1 modulate the sulphation grade of chondro-disaccharides in porcine articular cartilage: a capillary electrophoresis study.

    Science.gov (United States)

    Zanni, M; Tamburro, A; Rotilio, D

    1995-07-01

    This report describes the effect of interleukin-1 beta (IL-1 beta) and transforming growth factor-beta 1 (TGF-beta 1) on proteoglycan release from cartilage explants and modification at the sulphation level. Matrix proteoglycans purified by ion-exchange chromatography were composed of two distinct peaks (1 and 2) each showing a different Kav value when they were subjected to size-exclusion chromatography on a Sepharose CL-2B column. Glycosaminoglycans (GAGs) of conditioned medium and extracellular matrix proteoglycans were digested by chondroitin ABC and AC lyase, suggesting that chondroitin sulphate (CS) is the major GAG present (80-90%). Structural analysis of disaccharides, by capillary zone electrophoresis, revealed a different pattern of sulphated glycosaminoglycans when cartilage was treated with either IL-1 beta or TGF-beta 1. Analysis of GAGs released into the medium from TGF-beta 1 treated cartilage showed a reduction in the level of 4-S-disaccharide (delta Di4S) and an increase in non-sulphated disaccharides (delta Di0S), while no significant changes were found in IL-1 beta treated cartilage. In the extracellular matrix, IL-1 beta and TGF-beta 1 induced a more complex rearrangement of the GAGs. The level of non-sulphated disaccharides was increased whereas that of total sulphated disaccharides was reduced. Taken together, these results suggest that both cytokines modify the structure of GAGs, probably by interfering with the activity or the synthesis of sulphotransferases involved in GAG turnover. PMID:7551687

  5. Morphological changes of the cartilage and bone in newborn piglets evoked by experimentally induced glucocorticoid excess during pregnancy.

    Science.gov (United States)

    Tomaszewska, E; Dobrowolski, P; Puzio, I

    2013-08-01

    The study examined articular and growth plate cartilages as well as bone tissues in the offspring of sows treated with glucocorticoid during the last 45 days of pregnancy (dexamethasone at the dose of 0.03 mg/kg body weight intramuscularly, every second day). The offspring were tested at the birth and basal morphology for both articular and growth plate cartilages, and the histomorphometry of trabeculae of the epiphysis and metaphysis of femur and tibia were established. The concentration of selected cytokines and the activity of bone alkaline phosphatase were determined in blood serum. Maternal dexamethasone (DEX) administration reduced the thickness of proliferative, resting and hypertrophic zones of growth plate of femur and tibia of male piglets when compared with the control. DEX significantly reduced the thickness of the resting zone in both bones. It also elongated proliferative and hypertrophic zones of the growth plate in the femur as well as the hypertrophic zone in the tibia of female piglets when compared with the control group. Moreover, DEX decreased the articular cartilage thickness of the tibia in female piglets and enhanced the articular cartilage thickness of the femur in male piglets. Articular cartilage was highly cellular, and chondrocytes were separated by thin septa of matrix. An analysis of the trabecular bone architecture in male piglets showed a loss of the trabecular bone by thinning and DEX-related increase in trabecular porosity. Moreover, the cortical bone looked similar to the trabeculae because of trabecularization of the cortex. There was a DEX that reduced serum osteocalcin and BAP concentrations in both female and male newborn piglets, whereas the serum IL-1 and Il-6 was reduced only in male piglets. The obtained results demonstrated that DEX administration to sows during the last 45 days of pregnancy might cause the growth to slow and eventually to stop, especially in male piglets. It might lead to an alteration within the

  6. A Study On Employee Turnover At Prime Star Fashions, Tirupur

    OpenAIRE

    SHEELAVATHY, R.; HEMALATHA, Mrs.

    2015-01-01

    Employee turnover means number of incoming and outgoing worker from an organization or company. In other words we can say when a new employee takes place of old employee it is called employee turnover in a period of time. The main objective of perusing the study is to assess the main reasons for employee turnover, to know the retention techniques to avoid the employee turnover, to know about the effectiveness of supervising at Prime Star Fashions, Tirupur. The reason for the employee turnover...

  7. DETERMINANTS OF TURNOVER INTENTIONS AMONG CHINESE OFF FARM MIGRANTS

    OpenAIRE

    Russell Smyth; Qingguo Zhai; Xiaoxu Li

    2008-01-01

    This study examines the determinants of turnover intentions of off farm migrant workers, using data collected from China's Jiangsu Province. Turnover intention is posited to be a function of demographic/human capital characteristics, job characteristics and job satisfaction. We find that higher levels of education have a positive effect on reported turnover intentions, while higher income and job satisfaction have a negative effect on turnover intentions. As turnover intentions represent a go...

  8. Magnetic Resonance Imaging of Cartilage Contact and Bound Water in ACL-Deficient and ACL Reconstructed Knees

    Science.gov (United States)

    Baer, Geoffrey Scott; Kaiser, Jarred; Vignos, Michael; Liu, Fang; Smith, Colin Robert; Kijowski, Richard; Thelen, Darryl

    2016-01-01

    Objectives: Osteoarthritis (OA) is common following ACL-reconstructive (ACLR) surgery (6). The cause of early OA is not understood, but theories have focused on osteochondral damage at the time of injury (2) and abnormal joint mechanics following surgical repair (7). In this study, we investigate the inter-relationship of cartilage mechanics and biomarkers of OA in both ACL-deficient (ACLD) and ACLR knees. Our approach employs a novel dynamic MR sequence to measure joint mechanics (3) and the recently developed mcDESPOT to assess regional variations in water bound to proteoglycan (PG) (5). We hypothesize that bound water will be diminished in the cartilage of ACLD knees and, after surgery, will continue to adapt in a manner that reflects altered cartilage loading. This abstract presents initial observations on a cross-section of healthy, ACLD and ACLR knees. Methods: The dominant knees of 8 healthy controls, ACLD knees of 5 patients and ACLR knees of 8 patients were imaged in a 3 T MRI scanner (Table). Controls had no history of pain, injury, or surgery to their knee. Patients had no additional ligament injury and no meniscal damage. ACLD subjects were imaged prior to reconstructive surgery. Femoral and tibial cartilage were segmented from MR images and cartilage thickness was calculated. The mcDESPOT sequence provided a fraction map of water bound to PG (Fpg). Subjects flexed their knee against an inertial load at 0.5 Hz, while a SPGR-VIPR sequence continuously acquired volumetric data. Kinematics were obtained using model tracking of the dynamic images (3). Cartilage was registered to the bone segments for all frames, and contact patterns were characterized by the proximity between surfaces. Spatial representations of tibial cartilage contact, thickness and Fpg were co-registered for each subject. Results: Our initial images suggest lower Fpg values in ACLD knees, primarily on the posterior-lateral tibia. This is also observed in ACLR knees, with additional

  9. Predictors of Staff Turnover and Turnover Intentions within Addiction Treatment Settings: Change Over Time Matters.

    Science.gov (United States)

    Garner, Bryan R; Hunter, Brooke D

    2014-01-01

    This study examined the extent to which changes over time in clinicians' responses to measures of work attitude (eg, job satisfaction) and psychological climate (eg, supervisor support) could predict actual turnover and turnover intentions above and beyond absolute levels of these respective measures. Longitudinal data for this study were collected from a sample of clinicians (N = 96) being trained to implement an evidence-based treatment for adolescent substance use disorders. Supporting findings from a recent staff turnover study, we found job satisfaction change was able to predict actual turnover above and beyond average levels of job satisfaction. Representing new contributions to the staff turnover literature, we also found that change over time in several other key measures (eg, job satisfaction, role manageability, role clarity) explained a significant amount of variance in turnover intentions above and beyond the absolute level of each respective measure. A key implication of the current study is that organizations seeking to improve their ability to assess risk for staff turnover may want to consider assessing staff at multiple points in time in order to identify systematic changes in key employee attitudes like turnover intentions and job satisfaction. PMID:25336960

  10. FT-IR Microspectroscopy of Rat Ear Cartilage.

    Directory of Open Access Journals (Sweden)

    Benedicto de Campos Vidal

    Full Text Available Rat ear cartilage was studied using Fourier transform-infrared (FT-IR microspectroscopy to expand the current knowledge which has been established for relatively more complex cartilage types. Comparison of the FT-IR spectra of the ear cartilage extracellular matrix (ECM with published data on articular cartilage, collagen II and 4-chondroitin-sulfate standards, as well as of collagen type I-containing dermal collagen bundles (CBs with collagen type II, was performed. Ear cartilage ECM glycosaminoglycans (GAGs were revealed histochemically and as a reduction in ECM FT-IR spectral band heights (1140-820 cm-1 after testicular hyaluronidase digestion. Although ear cartilage is less complex than articular cartilage, it contains ECM components with a macromolecular orientation as revealed using polarization microscopy. Collagen type II and GAGs, which play a structural role in the stereo-arrangement of the ear cartilage, contribute to its FT-IR spectrum. Similar to articular cartilage, ear cartilage showed that proteoglycans add a contribution to the collagen amide I spectral region, a finding that does not recommend this region for collagen type II quantification purposes. In contrast to articular cartilage, the symmetric stretching vibration of -SO3- groups at 1064 cm-1 appeared under-represented in the FT-IR spectral profile of ear cartilage. Because the band corresponding to the asymmetric stretching vibration of -SO3- groups (1236-1225 cm-1 overlapped with that of amide III bands, it is not recommended for evaluation of the -SO3- contribution to the FT-IR spectrum of the ear cartilage ECM. Instead, a peak (or shoulder at 1027-1016 cm-1 could be better considered for this intent. Amide I/amide II ratios as calculated here and data from the literature suggest that protein complexes of the ear cartilage ECM are arranged with a lower helical conformation compared to pure collagen II. The present results could motivate further studies on this tissue

  11. FT-IR Microspectroscopy of Rat Ear Cartilage.

    Science.gov (United States)

    Vidal, Benedicto de Campos; Mello, Maria Luiza S

    2016-01-01

    Rat ear cartilage was studied using Fourier transform-infrared (FT-IR) microspectroscopy to expand the current knowledge which has been established for relatively more complex cartilage types. Comparison of the FT-IR spectra of the ear cartilage extracellular matrix (ECM) with published data on articular cartilage, collagen II and 4-chondroitin-sulfate standards, as well as of collagen type I-containing dermal collagen bundles (CBs) with collagen type II, was performed. Ear cartilage ECM glycosaminoglycans (GAGs) were revealed histochemically and as a reduction in ECM FT-IR spectral band heights (1140-820 cm-1) after testicular hyaluronidase digestion. Although ear cartilage is less complex than articular cartilage, it contains ECM components with a macromolecular orientation as revealed using polarization microscopy. Collagen type II and GAGs, which play a structural role in the stereo-arrangement of the ear cartilage, contribute to its FT-IR spectrum. Similar to articular cartilage, ear cartilage showed that proteoglycans add a contribution to the collagen amide I spectral region, a finding that does not recommend this region for collagen type II quantification purposes. In contrast to articular cartilage, the symmetric stretching vibration of -SO3- groups at 1064 cm-1 appeared under-represented in the FT-IR spectral profile of ear cartilage. Because the band corresponding to the asymmetric stretching vibration of -SO3- groups (1236-1225 cm-1) overlapped with that of amide III bands, it is not recommended for evaluation of the -SO3- contribution to the FT-IR spectrum of the ear cartilage ECM. Instead, a peak (or shoulder) at 1027-1016 cm-1 could be better considered for this intent. Amide I/amide II ratios as calculated here and data from the literature suggest that protein complexes of the ear cartilage ECM are arranged with a lower helical conformation compared to pure collagen II. The present results could motivate further studies on this tissue under

  12. Aggrecan nanoscale solid-fluid interactions are a primary determinant of cartilage dynamic mechanical properties.

    Science.gov (United States)

    Nia, Hadi Tavakoli; Han, Lin; Bozchalooi, Iman Soltani; Roughley, Peter; Youcef-Toumi, Kamal; Grodzinsky, Alan J; Ortiz, Christine

    2015-03-24

    Poroelastic interactions between interstitial fluid and the extracellular matrix of connective tissues are critical to biological and pathophysiological functions involving solute transport, energy dissipation, self-stiffening and lubrication. However, the molecular origins of poroelasticity at the nanoscale are largely unknown. Here, the broad-spectrum dynamic nanomechanical behavior of cartilage aggrecan monolayer is revealed for the first time, including the equilibrium and instantaneous moduli and the peak in the phase angle of the complex modulus. By performing a length scale study and comparing the experimental results to theoretical predictions, we confirm that the mechanism underlying the observed dynamic nanomechanics is due to solid-fluid interactions (poroelasticity) at the molecular scale. Utilizing finite element modeling, the molecular-scale hydraulic permeability of the aggrecan assembly was quantified (kaggrecan = (4.8 ± 2.8) × 10(-15) m(4)/N·s) and found to be similar to the nanoscale hydraulic permeability of intact normal cartilage tissue but much lower than that of early diseased tissue. The mechanisms underlying aggrecan poroelasticity were further investigated by altering electrostatic interactions between the molecule's constituent glycosaminoglycan chains: electrostatic interactions dominated steric interactions in governing molecular behavior. While the hydraulic permeability of aggrecan layers does not change across species and age, aggrecan from adult human cartilage is stiffer than the aggrecan from newborn human tissue. PMID:25758717

  13. On gigahertz spectral turnovers in pulsars

    CERN Document Server

    Rajwade, Kaustubh; Anderson, Loren D

    2015-01-01

    Pulsars are known to emit non-thermal radio emission that is generally a power-law function of frequency. In some cases, a turnover is seen at frequencies around 100~MHz. Kijak et al. have reported the presence of a new class of ''Gigahertz Peaked Spectrum'' (GPS) pulsars that show spectral turnovers at frequencies around 1 GHz. We apply a model based on free-free thermal absorption to explain these turnovers in terms of surrounding material such as the dense environments found in HII regions, Pulsar Wind Nebulae (PWNe), or in cold, partially ionized molecular clouds. We show that the turnover frequency depends on the electron temperature of the environment close to the pulsar, as well as the emission measure along the line of sight. We fitted this model to the radio fluxes of known GPS pulsars and show that it can replicate the GHz turnover. From the thermal absorption model, we demonstrate that normal pulsars would exhibit a GPS-like behaviour if they were in a dense environment. We discuss the application ...

  14. Computational model for the analysis of cartilage and cartilage tissue constructs.

    Science.gov (United States)

    Smith, David W; Gardiner, Bruce S; Davidson, John B; Grodzinsky, Alan J

    2016-04-01

    We propose a new non-linear poroelastic model that is suited to the analysis of soft tissues. In this paper the model is tailored to the analysis of cartilage and the engineering design of cartilage constructs. The proposed continuum formulation of the governing equations enables the strain of the individual material components within the extracellular matrix (ECM) to be followed over time, as the individual material components are synthesized, assembled and incorporated within the ECM or lost through passive transport or degradation. The material component analysis developed here naturally captures the effect of time-dependent changes of ECM composition on the deformation and internal stress states of the ECM. For example, it is shown that increased synthesis of aggrecan by chondrocytes embedded within a decellularized cartilage matrix initially devoid of aggrecan results in osmotic expansion of the newly synthesized proteoglycan matrix and tension within the structural collagen network. Specifically, we predict that the collagen network experiences a tensile strain, with a maximum of ~2% at the fixed base of the cartilage. The analysis of an example problem demonstrates the temporal and spatial evolution of the stresses and strains in each component of a self-equilibrating composite tissue construct, and the role played by the flux of water through the tissue. Copyright © 2013 John Wiley & Sons, Ltd. PMID:23784936

  15. Computational model for the analysis of cartilage and cartilage tissue constructs

    Science.gov (United States)

    Smith, David W.; Gardiner, Bruce S.; Davidson, John B.; Grodzinsky, Alan J.

    2013-01-01

    We propose a new non-linear poroelastic model that is suited to the analysis of soft tissues. In this paper the model is tailored to the analysis of cartilage and the engineering design of cartilage constructs. The proposed continuum formulation of the governing equations enables the strain of the individual material components within the extracellular matrix (ECM) to be followed over time, as the individual material components are synthesized, assembled and incorporated within the ECM or lost through passive transport or degradation. The material component analysis developed here naturally captures the effect of time-dependent changes of ECM composition on the deformation and internal stress states of the ECM. For example, it is shown that increased synthesis of aggrecan by chondrocytes embedded within a decellularized cartilage matrix initially devoid of aggrecan results in osmotic expansion of the newly synthesized proteoglycan matrix and tension within the structural collagen network. Specifically, we predict that the collagen network experiences a tensile strain, with a maximum of ~2% at the fixed base of the cartilage. The analysis of an example problem demonstrates the temporal and spatial evolution of the stresses and strains in each component of a self-equilibrating composite tissue construct, and the role played by the flux of water through the tissue. PMID:23784936

  16. A useful technique for adjusting nasal tip projection in Asian rhinoplasty: Trapezoidal caudal extension cartilage grafting.

    Science.gov (United States)

    Liu, Shao-Cheng; Lin, Deng-Shan; Wang, Hsing-Won; Kao, Chuan-Hsiang

    2016-01-01

    The purpose of this article is to present our experience with Asian patients in (1) using a trapezoidal caudal extension cartilage graft to adjust the tip projection in tip refinement for augmentation rhinoplasty, especially for the correction of short nose, and (2) avoiding complications of augmentation rhinoplasty with alloplastic implants. We conducted a retrospective chart review of 358 rhinoplasties that were performed by the corresponding author from January 2004 through July 2009. Patients were included in this study if they had undergone open rhinoplasty with a trapezoidal caudal extension cartilage graft as the only tip-modifying procedure. Patients in whom any additional grafting was performed that might have altered the nasal tip position were excluded. The surgical results were analyzed in terms of the degree of satisfaction judged separately by investigators and by patients. A total of 84 patients-46 males and 38 females, all Asians, aged 13 to 61 years (mean: 29.3)-met our eligibility criteria. Postoperative follow-up for 24 months was achieved in 62 patients. At the 24-month follow-up, the surgeons judged the results to be good or very good in 57 of the 62 patients (91.9%); at the same time, 56 patients (90.3%) said they were satisfied or very satisfied with their aesthetic outcome. Good nasal tip projection, a natural columellar appearance, and improvement in the nasolabial angle were achieved for most patients. Two patients required revision rhinoplasty to correct an insufficient augmentation and migration of the onlay graft. No severe complications were observed during the 2-year follow-up. We have found that trapezoidal caudal extension cartilage grafting in nasal tip refinement is an easy technique to learn and execute, its results are predictable, and it has been associated with no major complications. We recommend trapezoidal caudal extension cartilage grafting for Asian patients as a good and reliable alternative for managing tip projection

  17. Designed composites for mimicking compressive mechanical properties of articular cartilage matrix.

    Science.gov (United States)

    Zhu, Youjia; Wu, Hua; Sun, Shaofa; Zhou, Ting; Wu, Jingjing; Wan, Ying

    2014-08-01

    Collagen, chitosan-polycaprolactone (CH-PCL) copolymer with PCL content of around 40wt% and chondroitin sulfate (CS) were mixed together at various ratios to prepare collagen/CH-PCL/CS composites and the resulting composites were used to build stratified porous scaffolds that are potentially applicable for articular cartilage repair. The ternary composites were designed in such a way that collagen content in the scaffolds decreased from the top layer to the bottom layer while the content of CH-PCL and CS altered in a reversed trend in order to reach partial similarity to cartilage matrix in the composition of main components. Porous structures inside collagen/CH-PCL/CS scaffolds were constructed using a low-temperature deposition processing technique and graded average pore-size and porosity for the scaffolds were established. Such produced scaffolds were further crosslinked using 1-ethyl-3-(3-dimethyl aminopropyl) carbodiimide under optimized conditions, and the obtained scaffolds showed well-defined elastic compressive properties. Compressive modulus (E) and stress at 10% strain (σ10) of full scaffolds in wet state reached about 2.8MPa and 0.3MPa, respectively, and meanwhile, E and σ10 of layers inside hydrated scaffolds changed in a gradient-increased manner from the top layer to the bottom layer with significant differences between contiguous layers, which partially mimics compressive mechanical properties of cartilage matrix. In addition, in vitro culture of cell-scaffold constructs exhibited that scaffolds were able to well support the ingrowth and migration of seeded cells, and cells also showed relatively uniform distribution throughout the scaffolds. These results suggest that the presently developed collagen/CH-PCL/CS scaffolds have promising potential for applications in articular cartilage repair. PMID:24793172

  18. Phosphorylation of proteoglycans from human articular cartilage

    International Nuclear Information System (INIS)

    Previous studies have shown that sulfated proteoglycans from human articular and epiphyseal cartilage were phosphorylated. These macromolecules contribute to the stiffness and resiliency of this tissue. We demonstrate here that the phosphate moieties are an integral part of proteoglycan subunits. Specifically, evidence is presented which indicates that proteoglycan monomers contain 3 to 4 phosphate moieties per core protein and that these appear to exist as phosphoserine residues. Furthermore, the data illustrate that human articular cartilage also contains more than 20 different phosphoproteins, some of which are closely associated with proteoglycan aggregates. Proteoglycan subunits were purified from extracts of articular cartilage or from media fractions which had been used to label tissue specimens with 32P-orthophosphate. Chemical and radiographic analyses revealed that the phosphate concentration with respect to sulfate and uronic acid content remained constant when purified proteoglycan monomers were subjected to equilibrium ultracentrifugation and size-exclusion chromatography. That the phosphate moieties were bound to proteoglycan monomers via monoester linkages was indicated by the release of 32P-orthophosphate from proteoglycan subunits incubated under mild alkaline conditions or reacted with acid or alkaline phosphatases. Identification of serine residues in the core protein as the sites of phosphorylation was made by autoradiography of thin layer plates on which hydrolyzed samples of purified 32P-proteoglycan subunits had been subjected to 2-dimensional electrophoresis/chromatography. Quantification of 3 to 4 phosphate moieties per core protein of 200,000 daltons was made by chemical analysis of inorganic phosphate released from proteoglycans by acid hydrolysis

  19. The Application of Polysaccharide Biocomposites to Repair Cartilage Defects

    Directory of Open Access Journals (Sweden)

    Feng Zhao

    2014-01-01

    Full Text Available Owing to own nature of articular cartilage, it almost has no self-healing ability once damaged. Despite lots of restore technologies having been raised in the past decades, no repair technology has smoothly substituted for damaged cartilage using regenerated cartilage tissue. The approach of tissue engineering opens a door to successfully repairing articular cartilage defects. For instance, grafting of isolated chondrocytes has huge clinical potential for restoration of cartilage tissue and cure of chondral injury. In this paper, SD rats are used as subjects in the experiments, and they are classified into three groups: natural repair (group A, hyaluronic acid repair (group B, and polysaccharide biocomposites repair (hyaluronic acid hydrogel containing chondrocytes, group C. Through the observation of effects of repairing articular cartilage defects, we concluded that cartilage repair effect of polysaccharide biocomposites was the best at every time point, and then the second best was hyaluronic acid repair; both of them were better than natural repair. Polysaccharide biocomposites have good biodegradability and high histocompatibility and promote chondrocytes survival, reproduction, and spliting. Moreover, polysaccharide biocomposites could not only provide the porous network structure but also carry chondrocytes. Consequently hyaluronic acid-based polysaccharide biocomposites are considered to be an ideal biological material for repairing articular cartilage.

  20. MORPHOMETRIC STUDY OF THYROID CARTILAGES IN WESTERN INDIA

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    Mohini M.Joshi

    2015-06-01

    Full Text Available Background: Morphometrical evaluation of the larynx has always been interesting for both morphologists and the physicians. A good understanding of the anatomy and the knowledge of variations in the laryngeal cartilages is important Objective: Objective of the present study was to collect exact and reliable morphometric data of thyroid cartilage in adult human larynx of regional population. Methods: The totals of 50 thyroid cartilage specimens were studied. The cartilages were preserved in 5% formalin. The measurements were taken with the help of Digital Vernier Caliper. The cartilages were weighed on Single pan electronic balance. For each of the parameters, the mean, standard deviation (S.D. and range was calculated. Results: Mean depth of superior thyroid notch was 9.7± 3.36 mm. Asymmetry between the length of superior horn of thyroid cartilages in left and right sides can be seen, but difference was not statistically significant (p>0.05. It is observed that inner thyroid angle varies from 55 to 1040 and outer thyroid angle varies from 53 to 990. In present study mean weight of thyroid cartilage was 6.70±1.55 grams. Conclusions: A fair amount of intersubject variability in the dimensions was observed. Bilateral asymmetry, though present in majority of specimens, was insignificant. Various dimensions of thyroid cartilages are smaller as compared to the western population.

  1. Crosstalk between cartilage and bone: when bone cytokines matter.

    Science.gov (United States)

    Funck-Brentano, Thomas; Cohen-Solal, Martine

    2011-04-01

    The cartilage damage which characterizes osteoarthritis is often accompanied by bone lesions. Joint integrity results from the balance in the physiological interactions between bone and cartilage. Several local factors regulate the physiological remodeling of cartilage, the disequilibrium of these leading to a higher cartilage catabolism. Several cytokines secreted by bone cells can induce chondrocyte differentiation, which suggests their role in the dialogue between both cells. Accumulative in vivo evidence shows that increased bone resorption occurs at an early stage in the development of osteoarthritis and that blocking bone-resorbing cytokines prevents cartilage damage, confirming the role of bone factors in the crosstalk of both tissues. Recently, molecules of the Wnt pathway have emerged as key regulators of bone and cartilage. Activation of Wnt/βcatenin induces an imbalance in cartilage homeostasis, and agonists/antagonists of Wnt are potential candidates for this interaction. This review will summarize what is known about the contribution of bone cytokines to the physiological remodeling of cartilage and in the pathophysiology of osteoarthritis. PMID:21596615

  2. Endogenous Cartilage Repair by Recruitment of Stem Cells.

    Science.gov (United States)

    Im, Gun-Il

    2016-04-01

    Articular cartilage has a very limited capacity for repair after injury. The adult body has a pool of stem cells that are mobilized during injury or disease. These cells exist inside niches in bone marrow, muscle, adipose tissue, synovium, and other connective tissues. A method that mobilizes this endogenous pool of stem cells will provide a less costly and less invasive alternative if these cells successfully regenerate defective cartilage. Traditional microfracture procedures employ the concept of bone marrow stimulation to regenerate cartilage. However, the regenerated tissue usually is fibrous cartilage, which has very poor mechanical properties compared to those of normal hyaline cartilage. A method that directs the migration of a large number of autologous mesenchymal stem cells toward injury sites, retains these cells around the defects, and induces chondrogenic differentiation that would enhance success of endogenous cartilage repair. This review briefly summarizes chemokines and growth factors that induce recruitment, proliferation, and differentiation of endogenous progenitor cells, endogenous cell sources for regenerating cartilage, scaffolds for delivery of bioactive factors, and bioadhesive materials that are necessary to bring about endogenous cartilage repair. PMID:26559963

  3. Combined role of type IX collagen and cartilage oligomeric matrix protein in cartilage matrix assembly: Cartilage oligomeric matrix protein counteracts type IX collagen-induced limitation of cartilage collagen fibril growth in mouse chondrocyte cultures

    NARCIS (Netherlands)

    Blumbach, K.; Bastiaansen-Jenniskens, Y.M.; Groot, J. de; Paulsson, M.; Osch, G.J.V.M. van; Zaucke, F.

    2009-01-01

    Objective. Defects in the assembly and composition of cartilage extracellular matrix are likely to result in impaired matrix integrity and increased susceptibility to cartilage degeneration. The aim of this study was to determine the functional interaction of the collagen fibril-associated proteins

  4. THIONIN STAINING OF PARAFFIN AND PLASTIC EMBEDDED SECTIONS OF CARTILAGE

    NARCIS (Netherlands)

    BULSTRA, SK; DRUKKER, J; KUIJER, R; BUURMAN, WA; VANDERLINDEN, AJ

    1993-01-01

    The usefulness of thionin for staining cartilage sections embedded in glycol methacrylate (GMA) and the effect of decalcification on cartilage sections embedded in paraffin and GMA were assessed. Short decalcification periods using 5% formic acid or 10% EDTA did not influence the staining properties

  5. Relative contribution of matrix metalloprotease and cysteine protease activities to cytokine-stimulated articular cartilage degradation

    DEFF Research Database (Denmark)

    Sondergaard, B C; Henriksen, K; Wulf, H;

    2006-01-01

    explants were stimulated with oncostatin M (OSM) 10 ng/ml and tumor necrosis factor-alpha (TNF-alpha) 20 ng/ml in the presence or absence of the broad-spectrum MMP inhibitor GM6001 and the cysteine protease inhibitor, E64. Cartilage degradation was evaluated in the conditioned medium by glycosaminoglycans...... vivo in CK null mice. CONCLUSION: Inhibition of MMP activity reduced both proteoglycan loss and type II collagen degradation. In contrast, inhibition of cysteine proteases resulted in an increase rather than a decrease in MMP derived fragments of collagen type II degradation, CTX-II, suggesting altered...

  6. Poroelasticity of Cartilage at the Nanoscale

    OpenAIRE

    Nia, Hadi Tavakoli; Han, Lin; Li, Yang; Ortiz, Christine; Grodzinsky, Alan

    2011-01-01

    Atomic-force-microscopy-based oscillatory loading was used in conjunction with finite element modeling to quantify and predict the frequency-dependent mechanical properties of the superficial zone of young bovine articular cartilage at deformation amplitudes, δ, of ∼15 nm; i.e., at macromolecular length scales. Using a spherical probe tip (R ∼ 12.5 μm), the magnitude of the dynamic complex indentation modulus, |E∗|, and phase angle, ϕ, between the force and tip displacement sinusoids, were me...

  7. Cartilage Aggrecan Can Undergo Self-Adhesion

    OpenAIRE

    Han, Lin; Dean, Delphine; Daher, Laura A.; Grodzinsky, Alan J.; Ortiz, Christine

    2008-01-01

    Here it is reported that aggrecan, the highly negatively charged macromolecule in the cartilage extracellular matrix, undergoes Ca2+-mediated self-adhesion after static compression even in the presence of strong electrostatic repulsion in physiological-like solution conditions. Aggrecan was chemically end-attached onto gold-coated planar silicon substrates and gold-coated microspherical atomic force microscope probe tips (end radius R ≈ 2.5 μm) at a density (∼40 mg/mL) that simulates physiolo...

  8. Tissue engineering of cartilages using biomatrices

    DEFF Research Database (Denmark)

    Melrose, J.; Chuang, C.; Whitelock, J.

    2008-01-01

    cartilage engineering approaches and many of these are discussed and their in vitro and in vivo applications covered in this review. Tissue engineering is entering an exciting era; significant advances have been made; however, many technical challenges remain to be solved before this technology becomes......Tissue engineering is an exciting new cross-disciplinary methodology which applies the principles of engineering and structure-function relationships between normal and pathological tissues to develop biological substitute to restore, maintain or improve tissue function. Tissue engineering...

  9. New developments in osteoarthritis and cartilage biology.

    Science.gov (United States)

    Poulet, Blandine; Staines, Katherine A

    2016-06-01

    Osteoarthritis (OA) is a degenerative joint disease and the most common form of arthritis. Characterised by articular cartilage loss, subchondral bone thickening and osteophyte formation, the OA joint afflicts much pain and disability. Whilst OA has been associated with many contributing factors, its underpinning molecular mechanisms are, nevertheless, not fully understood. Clinical management of OA is largely palliative and there is an ever growing need for an effective disease modifying treatment. This review discusses some of the recent progress in OA therapies in the different joint tissues affected by OA pathology. PMID:26921602

  10. Climate change amplifies gross nitrogen turnover in montane grasslands of Central Europe both in summer and winter seasons

    Science.gov (United States)

    Chen, Zhe; Wang, Changhui; Unteregelsbacher, Sebastian; Lu, Haiyan; Gschwendtner, Silvia; Gasche, Rainer; Kolar, Allison; Schloter, Michael; Butterbach-Bahl, Klaus; Dannenmann, Michael

    2016-04-01

    The carbon and nitrogen rich soils of montane grasslands are exposed to above average warming and to altered precipitation patterns as a result of global change. In order to investigate the consequences of climatic change for soil nitrogen turnover, we translocated intact plant-soil mesocosms along an elevational gradient. Following three years of equilibration, we monitored the dynamics of gross nitrogen turnover and ammonia oxidizing microbes over an entire year. Gross nitrogen turnover and gene levels of ammonia oxidizing bacteria (AOB) and archaea (AOA) showed pronounced seasonal dynamics. While both summer and winter periods equally contributed to cumulative annual N turnover, the highest gross N turnover and abundance of ammonia oxidizers were observed in frozen soil of climate change sites due to physical liberation of organic substrates and their rapid turnover in the unfrozen soil water film. The control site never experienced soil freezing due to a significant insulating snowpack. Climate change conditions accelerated gross N mineralization by 250% on average. The AOB community benefited more from increased soil ammonium production under climate change conditions than the AOA community and thus accounted for a significant increase in gross nitrification rates. Climate change impacts were restricted to the 2-6 cm topsoil and rarely occurred at 12-16 cm depth, where generally much lower N turnover was observed. Mineralization pulses in a changing climate may result in soil organic matter loss with their associated negative impacts on key soil functions. In this context, N cycling processes in frozen soil can be a hot spot for gross N turnover and thus be of paramount importance for understanding seasonal patterns, annual sum of N turnover and possible climate change feedbacks.

  11. Climate change amplifies gross nitrogen turnover in montane grasslands of Central Europe in both summer and winter seasons.

    Science.gov (United States)

    Wang, Changhui; Chen, Zhe; Unteregelsbacher, Sebastian; Lu, Haiyan; Gschwendtner, Silvia; Gasche, Rainer; Kolar, Allison; Schloter, Michael; Kiese, Ralf; Butterbach-Bahl, Klaus; Dannenmann, Michael

    2016-09-01

    The carbon- and nitrogen-rich soils of montane grasslands are exposed to above-average warming and to altered precipitation patterns as a result of global change. To investigate the consequences of climatic change for soil nitrogen turnover, we translocated intact plant-soil mesocosms along an elevational gradient, resulting in an increase of the mean annual temperature by approx. 2 °C while decreasing precipitation from approx. 1500 to 1000 mm. Following three years of equilibration, we monitored the dynamics of gross nitrogen turnover and ammonia-oxidizing bacteria (AOB) and archaea (AOA) in soils over an entire year. Gross nitrogen turnover and gene levels of AOB and AOA showed pronounced seasonal dynamics. Both summer and winter periods equally contributed to cumulative annual N turnover. However, highest gross N turnover and abundance of ammonia oxidizers were observed in frozen soil of the climate change site, likely due to physical liberation of organic substrates and their rapid turnover in the unfrozen soil water film. This effect was not observed at the control site, where soil freezing did not occur due to a significant insulating snowpack. Climate change conditions accelerated gross nitrogen mineralization by 250% on average. Increased N mineralization significantly stimulated gross nitrification by AOB rather than by AOA. However, climate change impacts were restricted to the 2-6 cm topsoil and rarely occurred at 12-16 cm depth, where generally much lower N turnover was observed. Our study shows that significant mineralization pulses occur under changing climate, which is likely to result in soil organic matter losses with their associated negative impacts on key soil functions. We also show that N cycling processes in frozen soil can be hot moments for N turnover and thus are of paramount importance for understanding seasonal patterns, annual sum of N turnover and possible climate change feedbacks. PMID:27173913

  12. REGENERATION OF ARTICULAR CARTILAGE UNDER THE IMPLANTATION OF BONE MATRIX

    Directory of Open Access Journals (Sweden)

    Yuri M. Iryanov, Nikolay A. Kiryanov, Olga V. Dyuriagina , Tatiana Yu. Karaseva, Evgenii A. Karasev

    2015-07-01

    Full Text Available Background: The damage or loss of articular cartilage is costly medical problem. The purpose of this work – morphological analysis of reparative chondrogenesis when implanted in the area of the knee joint cartilage of granulated mineralized bone matrix. Material and Methods: The characteristic features of the knee cartilage regeneration studied experimentally in pubertal Wistar rats after modeling a marginal perforated defect and implantation of granulated mineralized bone matrix obtained according to original technology without heat and demineralizing processing into the injury zone. Results: This biomaterial established to have pronounced chondro- and osteoinductive properties, and to provide prolonged activation of reparative process, accelerated organotypical remodeling and restoration of the articular cartilage injured. Conclusion: The data obtained demonstrate the efficacy of МВМ in clinical practice for the treatment of diseases and injuries of the articular cartilage.

  13. Follistatin Alleviates Synovitis and Articular Cartilage Degeneration Induced by Carrageenan

    Science.gov (United States)

    Yamada, Jun; Abula, Kahaer; Inoue, Makiko; Sekiya, Ichiro; Muneta, Takeshi

    2014-01-01

    Activins are proinflammatory cytokines which belong to the TGFβ superfamily. Follistatin is an extracellular decoy receptor for activins. Since both activins and follistatin are expressed in articular cartilage, we hypothesized that activin-follistatin signaling participates in the process of joint inflammation and cartilage degeneration. To test this hypothesis, we examined the effects of follistatin in a carrageenan-induced mouse arthritis model. Synovitis induced by intra-articular injection of carrageenan was significantly alleviated by preinjection with follistatin. Macrophage infiltration into the synovial membrane was significantly reduced in the presence of follistatin. In addition, follistatin inhibited proteoglycan erosion induced by carrageenan in articular cartilage. These data indicate that activin-follistatin signaling is involved in joint inflammation and cartilage homeostasis. Our data suggest that follistatin can be a new therapeutic target for inflammation-induced articular cartilage degeneration. PMID:25574420

  14. Simultaneous Magnetic Resonance Imaging and Consolidation Measurement of Articular Cartilage

    Directory of Open Access Journals (Sweden)

    Robert Mark Wellard

    2014-05-01

    Full Text Available Magnetic resonance imaging (MRI offers the opportunity to study biological tissues and processes in a non-disruptive manner. The technique shows promise for the study of the load-bearing performance (consolidation of articular cartilage and changes in articular cartilage accompanying osteoarthritis. Consolidation of articular cartilage involves the recording of two transient characteristics: the change over time of strain and the hydrostatic excess pore pressure (HEPP. MRI study of cartilage consolidation under mechanical load is limited by difficulties in measuring the HEPP in the presence of the strong magnetic fields associated with the MRI technique. Here we describe the use of MRI to image and characterize bovine articular cartilage deforming under load in an MRI compatible consolidometer while monitoring pressure with a Fabry-Perot interferometer-based fiber-optic pressure transducer.

  15. The significance of electromechanical and osmotic forces in the nonequilibrium swelling behavior of articular cartilage in tension.

    Science.gov (United States)

    Grodzinsky, A J; Roth, V; Myers, E; Grossman, W D; Mow, V C

    1981-11-01

    Studies were conducted of some of the nonequilibrium, electrolyte-activated, electromechanical and osmotic processes that can affect the tensile properties of articular cartilage. We measured changes in tensile force that were induced by altering the ionic environment of strips of cartilage held at fixed length. We compared the kinetics of changes in these macroscopically measured isometric tensile forces to theoretical estimates of the time constants that characterize the underlying physical and chemical mechanisms occurring within the cartilage specimens during the experiment. Changes in the tensile force induced by changing the bath neutral salt concentration surrounding the specimen appear to be rate-limited by the diffusion of the salt into the specimen. That is, the mechanical stress relaxation process resulting from changes in salt concentration seems to be occurring at least as rapidly as the diffusion of salt into the matrix. When the bath concentration of CaCl2 or HCl is varied, the rate of change in the resulting isometric stresses indicates that Ca++ and H+ ions are binding to the cartilage matrix macromolecules. PMID:7311487

  16. Biochemical effects on long-term frozen human costal cartilage

    Energy Technology Data Exchange (ETDEWEB)

    Santin, Stefany P.; Martinho Junior, Antonio C.; Yoshito, Daniele; Soares, Fernando A.N.; Mathor, Monica B., E-mail: mathor@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2011-07-01

    Currently, the progresses on treatment of musculoskeletal diseases with the evolving of artificial implants and the success of tissue transplantation between genetically different individuals have conducted to an increase in radiosterilization. Regarding to tissue transplantation, it is essential to have sterile tissue and many tissue banks use radiosterilization as an effective method to sterilize these tissues. However, high doses of ionizing radiation and the preservation method may induce structural modifications in the tissues, as degradation of structural scaffold, decreasing its mechanical properties. Particularly, cartilage have been preserved in high concentrations of glycerol or deep-frozen at -70 degree C for storage after radiosterilization. Therefore, it is important to study the modifications induced in cartilage by preservation methods and by radiosterilization to determine the appropriated parameters for high quality of human allografts. Costal cartilages were obtained from cadaveric donors and were frozen at -20 degree C for 2 years long in order to compare with previous studies for fresh, deep-frozen and glycerolised cartilages. The mechanical tests were carried out in a universal testing machine until sample failure. According our results, there is no significant statistical difference between stress at break of fresh, long-term - 20 degree C frozen cartilages and deep-frozen cartilage. This early result suggests, regarding to tensile property, that long-term - 20 degree C frozen cartilages corresponds to glycerolised costal cartilages irradiated with 25 kGy or deep-frozen cartilages irradiated with 25 and 50 kGy. Thus, this long-term frozen cartilages may be used for tissue banks, but more studies about effects of ionizing radiation are necessary. (author)

  17. Biochemical effects on long-term frozen human costal cartilage

    International Nuclear Information System (INIS)

    Currently, the progresses on treatment of musculoskeletal diseases with the evolving of artificial implants and the success of tissue transplantation between genetically different individuals have conducted to an increase in radiosterilization. Regarding to tissue transplantation, it is essential to have sterile tissue and many tissue banks use radiosterilization as an effective method to sterilize these tissues. However, high doses of ionizing radiation and the preservation method may induce structural modifications in the tissues, as degradation of structural scaffold, decreasing its mechanical properties. Particularly, cartilage have been preserved in high concentrations of glycerol or deep-frozen at -70 degree C for storage after radiosterilization. Therefore, it is important to study the modifications induced in cartilage by preservation methods and by radiosterilization to determine the appropriated parameters for high quality of human allografts. Costal cartilages were obtained from cadaveric donors and were frozen at -20 degree C for 2 years long in order to compare with previous studies for fresh, deep-frozen and glycerolised cartilages. The mechanical tests were carried out in a universal testing machine until sample failure. According our results, there is no significant statistical difference between stress at break of fresh, long-term - 20 degree C frozen cartilages and deep-frozen cartilage. This early result suggests, regarding to tensile property, that long-term - 20 degree C frozen cartilages corresponds to glycerolised costal cartilages irradiated with 25 kGy or deep-frozen cartilages irradiated with 25 and 50 kGy. Thus, this long-term frozen cartilages may be used for tissue banks, but more studies about effects of ionizing radiation are necessary. (author)

  18. Radiological observation of determination of sex by costal cartilage calcification

    International Nuclear Information System (INIS)

    The difference of patterns of costal cartilage calcification in male and female had been first described by Fischer in 1955. Thereafter several reports were published, but specific clinical significance was not found. During the period from January, 1978 to December, 1978, we, in the Department of Radiology, Jeonbug National University, studied 2164 cases that showed the entire 12 pairs of ribs. Among these we detected 1494 cases of costal cartilage calcification and frequent sites of calcification. Patterns of costal cartilage calcification were classified into six groups- type l: central, type II: marginal, type III: junctional type, type IV: railroad, type V: diffuse, type VI: mixed. Results are as follows; 1. In a total of 2164 cases, calcification of costal cartilage was present in 1494 cases(69.0%). Of 1181 males 780 cases(66.0%) showed calcification, and of 983 females 714 cases (72.6%) showed calcification. 2. In 439 cases of males, except for 341 cases that showed calcification within the first costal cartilage, patterns of costal cartilage calcification were as follows: marginal type in 265 cases (60.4%), junctional type in 134 cases (30.5%), mixed type in 21 cases (0.5%), central type in 17 cases(3.8%), and railroad type in 2 cases (0.5%). Diffuse type was not present. 3. In 492 cases of females, except of 222 cases that showed calcification within the first costal cartilage, patterns of costal cartilage calcification were as follows; central type in 336 cases (68.3%), junctional type in 94 cases(19.1%), mixed type in 24 cases (4.9%), railroad type in 19 cases (3.9%), and diffuse type in 14 cases (2.8%). 4. When central calcification was observed, predictive value to female was 94.7%. When marginal calcification was observed, predictive value to male was 987.4%. 5. Males frequently showed calcification in upper costal cartilages, and females in lower costal cartilages.

  19. Quantification of isotopic turnover in agricultural systems

    Science.gov (United States)

    Braun, A.; Auerswald, K.; Schnyder, H.

    2012-04-01

    The isotopic turnover, which is a proxy for the metabolic rate, is gaining scientific importance. It is quantified for an increasing range of organisms, from microorganisms over plants to animals including agricultural livestock. Additionally, the isotopic turnover is analyzed on different scales, from organs to organisms to ecosystems and even to the biosphere. In particular, the quantification of the isotopic turnover of specific tissues within the same organism, e.g. organs like liver and muscle and products like milk and faeces, has brought new insights to improve understanding of nutrient cycles and fluxes, respectively. Thus, the knowledge of isotopic turnover is important in many areas, including physiology, e.g. milk synthesis, ecology, e.g. soil retention time of water, and medical science, e.g. cancer diagnosis. So far, the isotopic turnover is quantified by applying time, cost and expertise intensive tracer experiments. Usually, this comprises two isotopic equilibration periods. A first equilibration period with a constant isotopic input signal is followed by a second equilibration period with a distinct constant isotopic input signal. This yields a smooth signal change from the first to the second signal in the object under consideration. This approach reveals at least three major problems. (i) The input signals must be controlled isotopically, which is almost impossible in many realistic cases like free ranging animals. (ii) Both equilibration periods may be very long, especially when the turnover rate of the object under consideration is very slow, which aggravates the first problem. (iii) The detection of small or slow pools is improved by large isotopic signal changes, but large isotopic changes also involve a considerable change in the input material; e.g. animal studies are usually carried out as diet-switch experiments, where the diet is switched between C3 and C4 plants, since C3 and C4 plants differ strongly in their isotopic signal. The

  20. Poroelasticity of cartilage at the nanoscale.

    Science.gov (United States)

    Nia, Hadi Tavakoli; Han, Lin; Li, Yang; Ortiz, Christine; Grodzinsky, Alan

    2011-11-01

    Atomic-force-microscopy-based oscillatory loading was used in conjunction with finite element modeling to quantify and predict the frequency-dependent mechanical properties of the superficial zone of young bovine articular cartilage at deformation amplitudes, δ, of ~15 nm; i.e., at macromolecular length scales. Using a spherical probe tip (R ~ 12.5 μm), the magnitude of the dynamic complex indentation modulus, |E*|, and phase angle, φ, between the force and tip displacement sinusoids, were measured in the frequency range f ~ 0.2-130 Hz at an offset indentation depth of δ(0) ~ 3 μm. The experimentally measured |E*| and φ corresponded well with that predicted by a fibril-reinforced poroelastic model over a three-decade frequency range. The peak frequency of phase angle, f(peak), was observed to scale linearly with the inverse square of the contact distance between probe tip and cartilage, 1/d(2), as predicted by linear poroelasticity theory. The dynamic mechanical properties were observed to be independent of the deformation amplitude in the range δ = 7-50 nm. Hence, these results suggest that poroelasticity was the dominant mechanism underlying the frequency-dependent mechanical behavior observed at these nanoscale deformations. These findings enable ongoing investigations of the nanoscale progression of matrix pathology in tissue-level disease. PMID:22067171

  1. Turnover of adenosine in plasma of human and dog blood

    International Nuclear Information System (INIS)

    To determine half-life and turnover of plasma adenosine, heparinized blood from healthy volunteers was incubated with radiolabeled adenosine in the physiological concentration range of 0.1-1 microM. Plasma levels of adenosine in vitro were 82 +/- 14 nM and were similar to those determined immediately after blood collection with a ''stopping solution.'' Dipyridamole (83 microM) and erythro-9(2-hydroxynon-3yl)-adenine (EHNA) (8 microM) did not measurably alter basal adenosine levels but completely blocked the uptake of added adenosine. Inhibition of ecto-5'-nucleotidase with 100 microM alpha, beta-methyleneadenosine 5'-diphosphate (AOPCP) reduced plasma adenosine to 22 +/- 6 nM. For the determination of adenosine turnover, the decrease in specific radioactivity of added [3H]adenosine was measured using a dipyridamole-containing stopping solution. Without altering basal adenosine levels, the half-life was estimated to be 0.6 s. Similar experiments were carried out with washed erythrocytes or in the presence of AOPCP, yielding half-lives of 0.7 and 0.9 s, respectively. When the initial adenosine concentration was 1 microM, its specific activity decreased by only 11% within 5 s, whereas total plasma adenosine exponentially decreased with a half-life of 1.5 s. Venous plasma concentrations were measured after relief of a 3-min forearm ischemia. Changes in plasma adenosine did not correlate well with changes in blood flow but were augmented in the presence of dipyridamole

  2. Abnormal cartilage from the mandibular condyle of stumpy (stm) mutant mice.

    OpenAIRE

    Johnson, D.R.

    1983-01-01

    The mammalian mandibular condyle is composed of secondary cartilage and may thus be susceptible to genes causing achondroplasia and which result in abnormal++ primary cartilage formation. This paper describes the secondary cartilage in the mandible of the stumpy achondroplastic mutation in the mouse: both primary and secondary cartilage are affected by the gene.

  3. Deginerative changes of femoral articular cartilage in the knee : comparative study of specimen sonography and pathology

    International Nuclear Information System (INIS)

    To determine the sonographic findings of degenerative change in femoral articular cartilage of the knee by comparative study of specimen sonography and pathology. We obtained 40 specimens of cartilage of the femur (20 medial and 20 lateral condylar) from 20 patients with osteoarthritis of the knee who had undergone total knee replacement. The specimens were placed in a saline-filled container and sonography was performed using a 10-MHz linear transducer. Sonographic abnormalities were evaluated at the cartilage surface, within the cartilage, and at the bone-cartilage interface, and were compared with the corresponding pathologic findings. In addition, cartilage thickness was measured at a representative portion of each femoral cartilage specimen and was compared with the thickness determined by sonography. 'Dot' lesions, irregularity or loss of the hyperechoic line, were demonstrated by sonography at the saline-cartilage interface of 14 cartilages. Pathologic examination showed that these findings corresponded to cleft, detachment, erosion, and degeneration. Irregularities in the hyperechoic line at the bone-cartilage interface were revealed by sonography in eight cartilages and were related to irregularity or loss of tidemark, downward displacement of the cartilage, and subchondral callus formation. Dot lesions, corresponding to cleft and degeneration, were noted within one cartilage. Cartilage thickness measured on specimen and by sonography showed no significant difference (p=0.446). Specimen sonography suggested that articular cartilage underwent degenerative histopathological change. Cartilage thickness measured by sonography exactly reflected real thickness

  4. Employee Development and Turnover Intention: Theory Validation

    Science.gov (United States)

    Rahman, Wali; Nas, Zekeriya

    2013-01-01

    Purpose: This study aims to examine the pattern of behavior of turnover intentions in developing countries "vis-a-vis" the one in advanced countries through the empirical data from public universities in Khyber Pakhtunkhwa, Pakistan. The study provides empirical evidence from academia in Pakistan, thereby enriching the understanding of…

  5. Labour Turnover in the Hospitality Industry

    Directory of Open Access Journals (Sweden)

    Ersan Suria Pranoto

    2011-04-01

    much increases when employees are far more specialised, more difficult to find and requires more training. Therefore, it is in the best interests of hospitality managers to understand the causes and the effects of turnover so that they may reduce its costs.

  6. Turnover of Public School Superintendents in Arizona

    Science.gov (United States)

    Meyer, Joyce Ntsoaki

    2013-01-01

    This study used a descriptive qualitative design utilizing a phenomenological approach to determine and examine the reasons behind the voluntary or involuntary turnover of Arizona school superintendents. Open-ended questions were used to interview five superintendents who had left their districts between 2008 and 2013 about their perceptions on…

  7. Teacher Turnover in Charter Schools. Research Brief

    Science.gov (United States)

    Stuit, David; Smith, Thomas M.

    2010-01-01

    The current study aimed to contribute to a deeper understanding of the organizational conditions of charter schools by examining teacher turnover. Using data from the National Center for Education Statistics (NCES) 2003-04 Schools and Staffing Survey (SASS) and the Teacher Follow-Up Survey (TFS), researchers from the National Center on School…

  8. A Turnover Model for the Mexican Maquiladoras.

    Science.gov (United States)

    Maertz, Carl P.; Stevens, Michael J.; Campion, Michael A.

    2003-01-01

    From interviews with 47 Mexican maquiladora workers, a model of voluntary turnover was created and compared with models from the United States, Canada, England, and Australia. Despite similarities, the cultural and economic environment affected the precise content of antecedents in the Mexican model. (Contains 63 references.) (SK)

  9. Endogenous Turnover of Cyanogenic Glycosides in Plants

    DEFF Research Database (Denmark)

    Picmanova, Martina

    revealed the formation of glycosides of amides, carboxylic acids and "anitriles", including their di- and triglycosides, evidently derived from CNglcs. Based on results common to the three phylogenetically unrelated plant species, a recycling endogenous turnover pathway for CNglcs was suggested in which...

  10. Labour Turnover Costs and Average Labour Demand

    OpenAIRE

    Bertola, Giuseppe

    1991-01-01

    The effect of labour turnover costs on average employment in a partial equilibrium model of labour demand, depends on the form of the revenue function, on the rates of discount and labour attrition, and on the relative size of hiring and firing costs. If discount and attrition rates are strictly positive, firing costs may well increase average employment even when hiring costs reduce it.

  11. Minor psychiatric morbidity and labour turnover.

    OpenAIRE

    Jenkins, R

    1985-01-01

    The relation of minor psychiatric morbidity with labour turnover is examined, using data from a study of young, predominantly middle class, white collar men and women. The results suggest that the presence of psychiatric symptomatology is at least as important as occupational attitudes in identifying individuals who would subsequently leave the organisation.

  12. Director Turnover: An Australian Academic Development Study

    Science.gov (United States)

    Fraser, Kym; Ryan, Yoni

    2012-01-01

    Although it can be argued that directors of central academic development units (ADUs) are critical to the implementation of university teaching and learning strategies, it would appear there is a high director turnover rate. While research in the USA, the UK, and Australia illustrates that ADUs are frequently closed or restructured, that research…

  13. Antecedents of Norwegian Beginning Teachers' Turnover Intentions

    Science.gov (United States)

    Tiplic, Dijana; Brandmo, Christian; Elstad, Eyvind

    2015-01-01

    This study aims at exploring several individual, organizational, and contextual factors that may affect beginning teachers' turnover intentions during their first years of practice. The sample consists of 227 beginning teachers (69% female and 31% male) from 133 schools in Norway. The results show four important antecedents of beginning teachers'…

  14. Normal Bone Turnover in Transient Hyperphosphatasemia

    Science.gov (United States)

    Kutilek, Stepan; Cervickova, Barbora; Bebova, Pavla; Kmonickova, Marie; Nemec, Vladimir

    2012-01-01

    Transient hyperphosphatasemia of infancy and early childhood (THI) is characterized by a temporary isolated elevation of serum alkaline phosphatase activity (ALP), predominantly its bone or liver isoform, in either sick or healthy children under 5 years of age. Return to normal ALP levels usually occurs within four months. Spontaneous rise of ALP might concern the physician, especially when treating seriously ill children. However, THI is considered a benign biochemical disorder with no clinical consequences. Some existing reports support the hypothesis that THI is a result of increased bone turnover. We present evidence of normal bone turnover in two children with THI. In a one-year-old girl and a boy of the same age, high ALP levels (31 and 109 μkat/L, respectively) were accidentally detected. The children had no signs of metabolic bone disease or of liver disease. The high ALP levels returned to normal in two months, thus fulfilling the diagnosis of THI. In both patients, serum parathyroid hormone and bone turnover markers, serum CrossLaps, and serum osteocalcin were neither elevated, nor did these markers follow the ALP dynamics, thus reflecting normal bone turnover in THI. Children with THI should be spared from extensive investigations and unnecessary vitamin D treatment. Conflict of interest:None declared. PMID:22664360

  15. Modulation of bladder function by luminal adenosine turnover and A1 receptor activation

    OpenAIRE

    Prakasam, H. Sandeep; Herrington, Heather; Roppolo, James R.; Jackson, Edwin K.; Apodaca, Gerard

    2012-01-01

    The bladder uroepithelium transmits information to the underlying nervous and musculature systems, is under constant cyclical strain, expresses all four adenosine receptors (A1, A2A, A2B, and A3), and is a site of adenosine production. Although adenosine has a well-described protective effect in several organs, there is a lack of information about adenosine turnover in the uroepithelium or whether altering luminal adenosine concentrations impacts bladder function or overactivity. We observed ...

  16. Looking for a Challenge? Watch That Labour Turnover!

    Science.gov (United States)

    Wilkinson, Roderick

    1975-01-01

    Low labor turnover is an essential factor in the success of an enterprise. Steps in dealing with the turnover problem include: establish the objective, get the facts, decide what to do, take action, and check results. (MW)

  17. Work-Related Variables and Turnover Intention among Registered Nurses.

    Science.gov (United States)

    Pooyan, Abdullah; And Others

    1990-01-01

    Health institutions have become more interested in the causes of job turnover among registered nurses. Proper management of job turnover can improve the financial health and long-term survival of health care institutions. (Author)

  18. Analysis of Soil Structure Turnover with Garnet Particles and X-Ray Microtomography.

    Directory of Open Access Journals (Sweden)

    Steffen Schlüter

    Full Text Available Matter turnover in soil is tightly linked to soil structure which governs the heterogeneous distribution of habitats, reaction sites and pathways in soil. Thereby, the temporal dynamics of soil structure alteration is deemed to be important for essential ecosystem functions of soil but very little is known about it. A major reason for this knowledge gap is the lack of methods to study soil structure turnover directly at microscopic scales. Here we devise a conceptual approach and an image processing workflow to study soil structure turnover by labeling some initial state of soil structure with small garnet particles and tracking their fate with X-ray microtomography. The particles adhere to aggregate boundaries at the beginning of the experiment but gradually change their position relative to the nearest pore as structure formation progresses and pores are destructed or newly formed. A new metric based on the contact distances between particles and pores is proposed that allows for a direct quantification of soil structure turnover rates. The methodology is tested for a case study about soil compaction of a silty loam soil during stepwise increase of bulk density (ρ = {1.1, 1.3, 1.5} g/cm3. We demonstrate that the analysis of mean contact distances provides genuinely new insights about changing diffusion pathways that cannot be inferred neither from conventional pore space attributes (porosity, mean pore size, pore connectivity nor from deformation analysis with digital image correlation. This structure labeling approach to quantify soil structure turnover provides a direct analogy to stable isotope labeling for the analysis of matter turnover and can be readily combined with each other.

  19. Analysis of Soil Structure Turnover with Garnet Particles and X-Ray Microtomography.

    Science.gov (United States)

    Schlüter, Steffen; Vogel, Hans-Jörg

    2016-01-01

    Matter turnover in soil is tightly linked to soil structure which governs the heterogeneous distribution of habitats, reaction sites and pathways in soil. Thereby, the temporal dynamics of soil structure alteration is deemed to be important for essential ecosystem functions of soil but very little is known about it. A major reason for this knowledge gap is the lack of methods to study soil structure turnover directly at microscopic scales. Here we devise a conceptual approach and an image processing workflow to study soil structure turnover by labeling some initial state of soil structure with small garnet particles and tracking their fate with X-ray microtomography. The particles adhere to aggregate boundaries at the beginning of the experiment but gradually change their position relative to the nearest pore as structure formation progresses and pores are destructed or newly formed. A new metric based on the contact distances between particles and pores is proposed that allows for a direct quantification of soil structure turnover rates. The methodology is tested for a case study about soil compaction of a silty loam soil during stepwise increase of bulk density (ρ = {1.1, 1.3, 1.5} g/cm3). We demonstrate that the analysis of mean contact distances provides genuinely new insights about changing diffusion pathways that cannot be inferred neither from conventional pore space attributes (porosity, mean pore size, pore connectivity) nor from deformation analysis with digital image correlation. This structure labeling approach to quantify soil structure turnover provides a direct analogy to stable isotope labeling for the analysis of matter turnover and can be readily combined with each other. PMID:27453995

  20. Turnover of grain legume N rhizodeposits and effect of rhizodeposition on the turnover of crop residues

    DEFF Research Database (Denmark)

    Mayer, J.; Buegger, F.; Jensen, E.S.;

    2004-01-01

    The turnover of N derived from rhizodeposition of faba bean (Vicia faba L.), pea (Pisum sativum L.) and white lupin (Lupinus albus L.) and the effects of the rhizodeposition on the subsequent C and N turnover of its crop residues were investigated in an incubation experiment (168 days, 15 degrees...... experiment the turnover of C and N was compared in soils with and without previous growth of three legumes and with and without incorporation of crop residues. After 168 days, 21% (lupin), 26% (faba bean) and 27% (pea) of rhizodeposition N was mineralised in the treatments without crop residues. A smaller...... amount of 15-17% was present as microbial biomass and between 30 and 55% of mineralised rhizodeposition N was present as microbial residue pool, which consists of microbial exoenzymes, mucous substances and dead microbial biomass. The effect of rhizodeposition on the C and N turnover of crop residues was...

  1. The identification of matrix Gla protein in cartilage.

    Science.gov (United States)

    Hale, J E; Fraser, J D; Price, P A

    1988-04-25

    The vitamin K-dependent bone protein matrix gamma-carboxyglutamic acid (Gla) protein (MGP) has been identified by radioimmunoassay in the guanidine extract of rat cartilage. MGP was present in all cartilages tested at levels comparable to the MGP level in bone. Western blot analysis indicated that the molecular weight of cartilage MGP is the same as bone MGP, and Northern blot analysis revealed that MGP mRNA from cartilage is the same size as the MGP mRNA from bone. The structurally related vitamin K-dependent protein bone Gla protein could not be detected in cartilage by radioimmunoassay or by Northern blot analysis. The discovery that MGP is synthesized by growth plate cartilage could provide an explanation for the excessive growth plate mineralization disorder seen in rats treated with the vitamin K antagonist warfarin and the punctate mineralization of the growth plate seen in infants whose mothers received warfarin in the first trimester of pregnancy (the fetal warfarin syndrome). Both disorders appear to be caused by the inactivation of a vitamin K-dependent mineralization inhibitor in cartilage, an inhibitor which we suggest is MGP. PMID:3258600

  2. Critical temperature transitions in laser-mediated cartilage reshaping

    Science.gov (United States)

    Wong, Brian J.; Milner, Thomas E.; Kim, Hong H.; Telenkov, Sergey A.; Chew, Clifford; Kuo, Timothy C.; Smithies, Derek J.; Sobol, Emil N.; Nelson, J. Stuart

    1998-07-01

    In this study, we attempted to determine the critical temperature [Tc] at which accelerated stress relaxation occurred during laser mediated cartilage reshaping. During laser irradiation, mechanically deformed cartilage tissue undergoes a temperature dependent phase transformation which results in accelerated stress relaxation. When a critical temperature is attained, cartilage becomes malleable and may be molded into complex new shapes that harden as the tissue cools. Clinically, reshaped cartilage tissue can be used to recreate the underlying cartilaginous framework of structures such as the ear, larynx, trachea, and nose. The principal advantages of using laser radiation for the generation of thermal energy in tissue are precise control of both the space-time temperature distribution and time- dependent thermal denaturation kinetics. Optimization of the reshaping process requires identification of the temperature dependence of this phase transformation and its relationship to observed changes in cartilage optical, mechanical, and thermodynamic properties. Light scattering, infrared radiometry, and modulated differential scanning calorimetry (MDSC) were used to measure temperature dependent changes in the biophysical properties of cartilage tissue during fast (laser mediated) and slow (conventional calorimetric) heating. Our studies using MDSC and laser probe techniques have identified changes in cartilage thermodynamic and optical properties suggestive of a phase transformation occurring near 60 degrees Celsius.

  3. Predictors of Staff Turnover and Turnover Intentions within Addiction Treatment Settings: Change Over Time Matters

    OpenAIRE

    Garner, Bryan R.; Hunter, Brooke D.

    2014-01-01

    This study examined the extent to which changes over time in clinicians’ responses to measures of work attitude (eg, job satisfaction) and psychological climate (eg, supervisor support) could predict actual turnover and turnover intentions above and beyond absolute levels of these respective measures. Longitudinal data for this study were collected from a sample of clinicians (N = 96) being trained to implement an evidence-based treatment for adolescent substance use disorders. Supporting fin...

  4. Employee Turnover Intentions: Job Stress or Perceived Alternative External Opportunities

    OpenAIRE

    Dr Riyaz Ahmad Rainayee

    2013-01-01

    Turnover intention has been a critical issue for management for many years (Chen, Lin & Lien, 2010) and it is a major problem for organisations till now. Therefore, much attention has been paid over the past some years towards employees’ turnover behaviour and the major causes that lead towards the turnover intention of employees (Richer, Blanchard & Vallerandi, 2002).The broad range of turnover studies is indicative of the significance and complexity of the issue. The phenomenon attracts int...

  5. Antecedents of Turnover Intention Behavior among Nurses: A Theoretical Review

    OpenAIRE

    Mohammad Alhamwan; NorazuwaBt Mat.

    2015-01-01

    The employees’ turnover intention is one of the most popular subjects in the field of Human Resource Management. Moreover, the turnover problematic phenomenon is also still one of the most costly issues for HR managers in their efforts on human capital. Although turnover intention has been one of the most researched phenomenon in Human Resource Management (HRM), researchers still return to restudying this phenomenon because of its impact on service quality in any organization, moreover turnov...

  6. Structure and composition of arytenoid cartilage of the bullfrog (Lithobates catesbeianus) during maturation and aging.

    Science.gov (United States)

    Laureano, Priscila Eliane dos Santos; Oliveira, Kris Daiana Silva; de Aro, Andrea Aparecida; Gomes, Laurecir; Pimentel, Edson Rosa; Esquisatto, Marcelo Augusto Marretto

    2015-10-01

    chondroitin- and dermatan-sulfate especially in this age. The content of hydroxyproline, which infers the total collagen concentration, was higher in 1080-day-old animals compared to the other ages. The results demonstrated the elastic nature of the arytenoid cartilage of L. catesbeianus and the occurrence of age-related changes in the structural organization and composition of the extracellular matrix. These changes may contribute to alter the function of the larynx in the animal during aging. PMID:26093475

  7. Growing Three-Dimensional Cartilage-Cell Cultures

    Science.gov (United States)

    Spaulding, Glenn F.; Prewett, Tacey L.; Goodwin, Thomas J.

    1995-01-01

    Process for growing three-dimensional cultures of mammalian cartilage from normal mammalian cells devised. Effected using horizontal rotating bioreactor described in companion article, "Simplified Bioreactor for Growing Mammalian Cells" (MSC-22060). Bioreactor provides quiescent environment with generous supplies of nutrient and oxygen. Initiated with noncartilage cells. Artificially grown tissue resembles that in mammalian cartilage. Potential use in developing therapies for damage to cartilage by joint and back injuries and by such inflammatory diseases as arthritis and temporal-mandibular joint disease. Also used to test nonsteroid anti-inflammation medicines.

  8. Experimental articular cartilage repair in the Göttingen minipig

    DEFF Research Database (Denmark)

    Christensen, Bjørn Borsøe; Foldager, Casper Bindzus; Olesen, Morten Lykke;

    2015-01-01

    BACKGROUND: A gold standard treatment for articular cartilage injuries is yet to be found, and a cost-effective and predictable large animal model is needed to bridge the gap between in vitro studies and clinical studies. Ideally, the animal model should allow for testing of clinically relevant...... treatments and the biological response should be reproducible and comparable to humans. This allows for a reliable translation of results to clinical studies.This study aimed at verifying the Göttingen minipig as a pre-clinical model for articular cartilage repair by testing existing clinical cartilage...

  9. A Ministudy of employee turnover in US hospitals.

    Science.gov (United States)

    Collins, Sandra K; McKinnies, Richard C; Matthews, Eric P; Collins, Kevin S

    2015-01-01

    A ministudy was conducted to collect self-reported employee turnover rates in US hospitals. The results indicate many hospitals are struggling with high employee turnover rates. Widespread variances in ratings were observed across hospitals, which may be due to lack of consistency in how they each calculate their employee turnover. This makes benchmarking for the purposes of performance improvement challenging. PMID:25627851

  10. High School Band Students' Perspectives of Teacher Turnover

    Science.gov (United States)

    Kloss, Thomas E.

    2013-01-01

    Teacher turnover remains an important issue in education. The least researched perspectives, though, are those of the students who experience teacher turnover. The purpose of this study was to examine how high school band students experience teacher turnover. A total of twelve students were interviewed, representing three schools that experienced…

  11. Turn-over in pulsar spectra above 1 GHz

    OpenAIRE

    Kijak, J.; Gupta, Y; Krzeszowski, K.

    2007-01-01

    We present the first direct evidence for turn-over in pulsar radio spectra at high frequencies. Two pulsars are now shown to have a turn-over frequency > 1GHz. We also find some evidence that the peak frequency of turn-over in pulsar spectra appears to depend on dispersion measure and pulsar age.

  12. Superintendent Turnover in Kentucky. Issues & Answers. REL 2011-No. 113

    Science.gov (United States)

    Johnson, Jerry; Huffman, Tyler; Madden, Karen; Shope, Shane

    2011-01-01

    This study examines superintendent turnover in Kentucky public school districts for 1998/99-2007/08, looking at how turnover varies by rural status, Appalachian and non-Appalachian region, and 2007/08 school district characteristics. Key findings include: (1) Kentucky school districts averaged one superintendent turnover during 1998/99-2007/08;…

  13. Salary and Ranking and Teacher Turnover: A Statewide Study

    Science.gov (United States)

    Garcia, Cynthia Martinez; Slate, John R.; Delgado, Carmen Tejeda

    2009-01-01

    This study examined three years of data obtained from the Academic Excellence Indicator System of the State of Texas regarding teacher turnover rate and teacher salary. Across all public school districts, teacher salary was consistently negatively related to teacher turnover; that is, where salary was lower, turnover rate was higher When data were…

  14. Investing in Leadership: The District's Role in Managing Principal Turnover

    Science.gov (United States)

    Mascall, Blair; Leithwood, Kenneth

    2010-01-01

    This article presents the results of research into the impact of principal turnover on schools, and the ability of schools to mitigate the negative effects of frequent turnover by distributing leadership in the schools. The findings from this qualitative and quantitative analysis show that rapid principal turnover does indeed have a negative…

  15. The research methods and model of protein turnover in animal

    International Nuclear Information System (INIS)

    The author discussed the concept and research methods of protein turnover in animal body. The existing problems and the research results of animal protein turnover in recent years were presented. Meanwhile, the measures to improve the models of animal protein turnover were analyzed

  16. 41 CFR 109-27.5002 - Stores inventory turnover ratio.

    Science.gov (United States)

    2010-07-01

    ... turnover ratio. 109-27.5002 Section 109-27.5002 Public Contracts and Property Management Federal Property....5002 Stores inventory turnover ratio. Comparison of investment in stores inventories to annual issues... comparison may be expressed either as a turnover ratio (dollar value of issues divided by dollar value...

  17. Job Turnover and Job Satisfaction among Nursing Home Aides.

    Science.gov (United States)

    Waxman, Howard M.; And Others

    1984-01-01

    Interviewed 234 aides in seven nursing homes concerning job turnover rate, job satisfaction, and perception of milieu. A positive association found between turnover rate and aides' perceptions of the homes' order, organization, and control suggested that job turnover would lessen with more involvement in the decision-making process. (JAC)

  18. Premature Calcifications of Costal Cartilages: A New Perspective Premature Calcifications of Costal Cartilages: A New Perspective

    International Nuclear Information System (INIS)

    Calcifications of the costal cartilages occur, as a rule, not until the age of 30 years. The knowledge of the clinical significance of early and extensive calcifications is still incomplete. Materials and Methods. A search was made to find patients below the age of 30 years who showed distinct calcifications of their lower costal cartilages by viewing 360 random samples of intravenous pyelograms and abdominal plain films. The histories, and clinical and laboratory findings of these patients were analyzed. Results. Nineteen patients fulfilled the criteria of premature calcifications of costal cartilages (CCCs). The patients had in common that they were frequently referred to a hospital and were treated by several medical disciplines. Nevertheless many complaints of the patients remained unsolved. Premature CCCs were often associated with rare endocrine disorders, inborn errors of metabolism, and abnormal hematologic findings. Among the metabolic disorders there were 2 proven porphyrias and 7 patients with a suspected porphyria but with inconclusive laboratory findings. Conclusion. Premature CCCs are unlikely to be a normal variant in skeletal radiology. The findings in this small group of patients call for more intensive studies, especially in regard to the putative role of a porphyria

  19. Three-dimensional evaluation of cartilage thickness and cartilage volume in the knee joint with MR imaging: reproducibility in volunteers

    International Nuclear Information System (INIS)

    Objective: To determine the reproductibility of three-dimensional volume and thickness measurements of the knee joint cartilage with MRI in volunteers. Methods: The knees of 7 healthy individuals (ages 23 to 58 yrs.) were sagitally imaged with a resolution of 2x0.31x0.31 mm3, using a fat-suppressed FLASH-3 D sequence. The knee was repositioned in between replicate acquisitions, 6 data sets being obtained in each case. After semiautomatic segmentation and three-dimensional reconstruction of the cartilage, the thickness was determined independent of the original section orientation. The coefficient of variation for repeated volume measurements and the deviations of the maximal cartilage thickness values were calculated subsequently. Results: The mean variation of the cartilage volumes of the replicate measurements was 1.4% (±0.8%) in the patella, 1.7% (±1.5%) in the femur, 3.0% (±1.2%) in the medial tibial plateau and 3.5% (±2.0%) in the lateral tibial plateau. The comparison of the distribution patterns of cartilage thickness yielded a high degree of agreement. Only in rare cases deviations of more than 0.5 mm were observed. Conclusions: The results show that the presented method for determining the quantitative distribution of articular cartilage yields a high degree of precision. It offers new possibilities in screening risk groups, monitoring the course of degenerative joint disease and the investigation of functional adaptation of the cartilage to mechanical loading. (orig.)

  20. Estrogen regulates the rate of bone turnover but bone balance in ovariectomized rats is modulated by prevailing mechanical strain

    Science.gov (United States)

    Westerlind, K. C.; Wronski, T. J.; Ritman, E. L.; Luo, Z. P.; An, K. N.; Bell, N. H.; Turner, R. T.

    1997-01-01

    Estrogen deficiency induced bone loss is associated with increased bone turnover in rats and humans. The respective roles of increased bone turnover and altered balance between bone formation and bone resorption in mediating estrogen deficiency-induced cancellous bone loss was investigated in ovariectomized rats. Ovariectomy resulted in increased bone turnover in the distal femur. However, cancellous bone was preferentially lost in the metaphysis, a site that normally experiences low strain energy. No bone loss was observed in the epiphysis, a site experiencing higher strain energy. The role of mechanical strain in maintaining bone balance was investigated by altering the strain history. Mechanical strain was increased and decreased in long bones of ovariectomized rats by treadmill exercise and functional unloading, respectively. Functional unloading was achieved during orbital spaceflight and following unilateral sciatic neurotomy. Increasing mechanical loading reduced bone loss in the metaphysis. In contrast, decreasing loading accentuated bone loss in the metaphysis and resulted in bone loss in the epiphysis. Finally, administration of estrogen to ovariectomized rats reduced bone loss in the unloaded and prevented loss in the loaded limb following unilateral sciatic neurotomy in part by reducing indices of bone turnover. These results suggest that estrogen regulates the rate of bone turnover, but the overall balance between bone formation and bone resorption is influenced by prevailing levels of mechanical strain.

  1. Literature review of labour turnover and absenteeism costs in the coal mining industry

    Energy Technology Data Exchange (ETDEWEB)

    Woolf, A.

    1977-01-01

    This paper includes labor turnover formulae, turnover costs, and turnover rates for the mining industry. Few meaningful studies or reports on absenteeism costs and labour turnover in mining were retrieved.

  2. Butterfly cartilage graft versus fat graft myringoplasty

    Directory of Open Access Journals (Sweden)

    Sonika Kanotra

    2016-01-01

    Full Text Available Aim: The aim of the study was to compare the graft take up rates of two minimally invasive techniques of butterfly cartilage graft (BCG and fat graft myringoplasty (FGM. Materials and Methods: Two groups of 30 patients each with small dry central perforations of the tympanic membrane (T.M. were randomly subjected to either of the two techniques of myringoplasty. Statistical Analysis Used: The results were compared using the Chi-square test. A value of <0.05 was taken as statistically significant. Results: The graft take up rate was 93.3% with BCG and 83.3% with fat graft. Conclusions: The BCG scores over FGM in small perforations of the T.M.

  3. Polylactide fibrous scaffolds for cartilage implant engineering

    Czech Academy of Sciences Publication Activity Database

    Mulinková, Katarína; Machová, Luďka; Lesný, P.; Kubies, Dana; Rypáček, František

    Prague: Czech Society for New Materials and Technologies, 2005. Poster Session II. [European Congress on Advanced Materials and Processes. 5.9.2005-8.9.2005, Prague] R&D Projects: GA MZd ND7448 Keywords : biodegradable polymers * polylactide fibres * cartilage engineering Subject RIV: FJ - Surgery incl. Transplants http://webdb.dgm.de/dgm_lit/prg/FMPro?-db=w%5fprogram&- format =prog%5fpaper%5fresults.htm&-lay=standard&TB=%3d%3d688&tgb%5fsymposium%5fund%5fnr=B14%20Engineering%20and%20Design%20of%20Biomedical%20Materials&-max=20&-skip=20&-token.0=688&-token.1=B14%20Engineering%20and%20Design%20of%20Biomedical%20Materials&-find=

  4. How Serious of a Problem is Staff Turnover in Substance Abuse Treatment? A Longitudinal Study of Actual Turnover1

    OpenAIRE

    Eby, Lillian T.; Burk, Hannah; Maher, Charleen P.

    2010-01-01

    In the substance abuse treatment field, the annual turnover rate is cited as being anywhere between 19 and 50 percent (Johnson & Roman, 2002; Gallon, Gabriel, & Knudsen, 2003; Knudsen et al., 2003; McLellan et al., 2003). However, no research to date has evaluated these claims by tracking turnover longitudinally using organizational turnover data from substance abuse treatment centers. This research presents the results of a longitudinal study designed to systematically examine actual turnove...

  5. The development of the collagen fibre network in tissue-engineered cartilage constructs in vivo. Engineered cartilage reorganises fibre network

    Directory of Open Access Journals (Sweden)

    H Paetzold

    2012-04-01

    Full Text Available For long term durability of tissue-engineered cartilage implanted in vivo, the development of the collagen fibre network orientation is essential as well as the distribution of collagen, since expanded chondrocytes are known to synthesise collagen type I. Typically, these properties differ strongly between native and tissue-engineered cartilage. Nonetheless, the clinical results of a pilot study with implanted tissue-engineered cartilage in pigs were surprisingly good. The purpose of this study was therefore to analyse if the structure and composition of the artificial cartilage tissue changes in the first 52 weeks after implantation. Thus, collagen network orientation and collagen type distribution in tissue-engineered cartilage-carrier-constructs implanted in the knee joints of Göttinger minipigs for 2, 26 or 52 weeks have been further investigated by processing digitised microscopy images of histological sections. The comparison to native cartilage demonstrated that fibre orientation over the cartilage depth has a clear tendency towards native cartilage with increasing time of implantation. After 2 weeks, the collagen fibres of the superficial zone were oriented parallel to the articular surface with little anisotropy present in the middle and deep zones. Overall, fibre orientation and collagen distribution within the implants were less homogenous than in native cartilage tissue. Despite a relatively low number of specimens, the consistent observation of a continuous approximation to native tissue is very promising and suggests that it may not be necessary to engineer the perfect tissue for implantation but rather to provide an intermediate solution to help the body to heal itself.

  6. Organizational-level study of the impact of past turnover on future turnover in the Sultanate of Oman

    Directory of Open Access Journals (Sweden)

    Ruqaiya Mohamed Al Balushi

    2013-10-01

    Full Text Available Turnover phenomena attracted researchers from all over the world for generations. Most of this research was directed towards turnover antecedents with a few scattered conceptual and empirical studies related to turnover consequences. The purpose of this study is to investigate the impact of past turnover on future turnover in public organizations, in addition to test the mediation role of organizational climate in this relationship. Public schools as separate identities were the best choice as the study sample. Data were collected through questionnaires from 142 public schools in all educational regions in Oman. Two-step structural equation modeling approach, and nested model comparison were used for data analysis. The results revealed that: (1 past turnover predicts future turnover, significantly; (2 organizational climate fails to mediate this relationship. The study added to the body of knowledge by confirming Staw’s hypothesis relating past turnover to future turnover in the Omani context. Human resource professionals and educational administration practitioners may play an important role in decreasing future turnover by tackling and decreasing past turnover, in addition to improving the relationship climate in schools. The study is limited to public schools in Oman and further studies about turnover consequences in the Arabic context are needed to affirm the results.

  7. Evaluating the Role of Microbial Internal Storage Turnover on Nitrous Oxide Accumulation During Denitrification.

    Science.gov (United States)

    Liu, Yiwen; Peng, Lai; Guo, Jianhua; Chen, Xueming; Yuan, Zhiguo; Ni, Bing-Jie

    2015-01-01

    Biological wastewater treatment processes under a dynamic regime with respect to carbon substrate can result in microbial storage of internal polymers (e.g., polyhydroxybutyrate (PHB)) and their subsequent utilizations. These storage turnovers play important roles in nitrous oxide (N2O) accumulation during heterotrophic denitrification in biological wastewater treatment. In this work, a mathematical model is developed to evaluate the key role of PHB storage turnovers on N2O accumulation during denitrification for the first time, aiming to establish the key relationship between N2O accumulation and PHB storage production. The model is successfully calibrated and validated using N2O data from two independent experimental systems with PHB storage turnovers. The model satisfactorily describes nitrogen reductions, PHB storage/utilization, and N2O accumulation from both systems. The results reveal a linear relationship between N2O accumulation and PHB production, suggesting a substantial effect of PHB storage on N2O accumulation during denitrification. Application of the model to simulate long-term operations of a denitrifying sequencing batch reactor and a denitrifying continuous system indicates the feeding pattern and sludge retention time would alter PHB turnovers and thus affect N2O accumulation. Increasing PHB utilization could substantially raise N2O accumulation due to the relatively low N2O reduction rate when using PHB as carbon source. PMID:26463891

  8. Norepinephrine turnover in brown adipose tissue is stimulated by a single meal

    Energy Technology Data Exchange (ETDEWEB)

    Glick, Z.; Raum, W.J.

    1986-07-01

    A single meal stimulates brown adipose tissue (BAT) thermogenesis in rats. In the present study the role of norepinephrine in this thermogenic response was assessed from the rate of its turnover in BAT after a single test meal. For comparison, norepinephrine turnover was determined in the heart and spleen. A total of 48 male Wistar rats (200 g) were trained to eat during two feeding sessions per day. On the experimental day, one group (n = 24) was meal deprived and the other (n = 24) was given a low-protein high-carbohydrate test meal for 2 h. The synthesis inhibition method with ..cap alpha..-methyl-p-tyrosine was employed to determine norepinephrine turnover from its concentration at four hourly time points after the meal. Tissue concentrations of norepinephrine were determined by radioimmunoassay. Norepinephrine concentration and turnover rate were increased more than threefold in BAT of the meal-fed compared with the meal-deprived rats. Neither were significantly altered by the meal in the heart or spleen. The data suggest that norepinephrine mediates a portion of the thermic effect of meals that originate in BAT.

  9. Norepinephrine turnover in brown adipose tissue is stimulated by a single meal

    International Nuclear Information System (INIS)

    A single meal stimulates brown adipose tissue (BAT) thermogenesis in rats. In the present study the role of norepinephrine in this thermogenic response was assessed from the rate of its turnover in BAT after a single test meal. For comparison, norepinephrine turnover was determined in the heart and spleen. A total of 48 male Wistar rats (200 g) were trained to eat during two feeding sessions per day. On the experimental day, one group (n = 24) was meal deprived and the other (n = 24) was given a low-protein high-carbohydrate test meal for 2 h. The synthesis inhibition method with α-methyl-p-tyrosine was employed to determine norepinephrine turnover from its concentration at four hourly time points after the meal. Tissue concentrations of norepinephrine were determined by radioimmunoassay. Norepinephrine concentration and turnover rate were increased more than threefold in BAT of the meal-fed compared with the meal-deprived rats. Neither were significantly altered by the meal in the heart or spleen. The data suggest that norepinephrine mediates a portion of the thermic effect of meals that originate in BAT

  10. Cartilage (Bovine and Shark) (PDQ®)—Health Professional Version

    Science.gov (United States)

    Expert-reviewed information summary about the use of bovine and shark cartilage as a treatment for people with cancer. Note: The information in this summary is no longer being updated and is provided for reference purposes only.

  11. Now approaches to the treatment of articular cartilage lesions

    Directory of Open Access Journals (Sweden)

    M. Coviello

    2011-01-01

    Full Text Available Various approaches to the treatment of cartilage defects have been proposed in the literature; reparative and regenerative methods and, more recently, the Maioregen technique are currently available.

  12. Endobronchial Cartilage Rupture: A Rare Cause of Lobar Collapse.

    Science.gov (United States)

    Dasa, Osama; Siddiqui, Nauman; Ruzieh, Mohammed; Javaid, Toseef

    2016-01-01

    Endobronchial cartilage rupture is a rare clinical condition, which can present in patients with severe emphysema with sudden onset shortness of breath. We present a case of a 62-year-old male who presented to our emergency department with sudden onset shortness of breath. Chest X-ray showed lung hyperinflation and a right lung field vague small density. Chest Computed Tomography confirmed the presence of right middle lobe collapse. Bronchoscopy revealed partial right middle lobe atelectasis and an endobronchial cartilage rupture. Endobronchial cartilage rupture is a rare condition that can present as sudden onset shortness of breath due to lobar collapse in patients with emphysema and can be triggered by cough. Bronchoscopic findings include finding a collapsed lung lobe and a visible ruptured endobronchial cartilage. A high index of suspicion, chest imaging, and early bronchoscopy can aid in the diagnosis and help prevent complications. PMID:27525149

  13. Namaste (counterbalancing technique: Overcoming warping in costal cartilage

    Directory of Open Access Journals (Sweden)

    Kapil S Agrawal

    2015-01-01

    Full Text Available Background: Indian noses are broader and lack projection as compared to other populations, hence very often need augmentation, that too by large volume. Costal cartilage remains the material of choice in large volume augmentations and repair of complex primary and secondary nasal deformities. One major disadvantage of costal cartilage grafts (CCG which offsets all other advantages is the tendency to warp and become distorted over a period of time. We propose a simple technique to overcome this menace of warping. Materials and Methods: We present the data of 51 patients of rhinoplasty done using CCG with counterbalancing technique over a period of 4 years. Results: No evidence of warping was found in any patient up to a maximum follow-up period of 4 years. Conclusion: Counterbalancing is a useful technique to overcome the problem of warping. It gives liberty to utilize even unbalanced cartilage safely to provide desired shape and use the cartilage without any wastage.

  14. The sulphation of chondroitin sulphate in embryonic chicken cartilage

    Science.gov (United States)

    Robinson, H. C.

    1969-01-01

    1. Whole tissue preparations and subcellular fractions from embryonic chicken cartilage were used to measure the rate of incorporation of inorganic sulphate into chondroitin sulphate in vitro. 2. In cartilage from 14-day-old embryos, [35S]sulphate is incorporated to an equal extent into chondroitin 4-sulphate and chondroitin 6-sulphate at a rate of 1·5nmoles of sulphate/hr./mg. dry wt. of cartilage. 3. Microsomal and soluble enzyme preparations from embryonic cartilage catalyse the transfer of sulphate from adenosine 3′-phosphate 5′-sulphatophosphate into both chondroitin 4-sulphate and chondroitin 6-sulphate. 4. The effects of pH, ionic strength, adenosine 3′-phosphate 5′-sulphatophosphate concentration and acceptor chondroitin sulphate concentration on the soluble sulphotransferase activity were examined. These factors all influence the activity of the sulphotransferase, and pH and incubation time also influence the percentage of chondroitin 4-sulphate formed. PMID:5807213

  15. Cartilage oligomeric matrix protein in patients with juvenile idiopathic arthritis

    DEFF Research Database (Denmark)

    Bjørnhart, Birgitte; Juul, Anders; Nielsen, Susan;

    2009-01-01

    Cartilage oligomeric matrix protein (COMP) has been identified as a prognostic marker of progressive joint destruction in rheumatoid arthritis. In this population based study we evaluated associations between plasma concentrations of COMP, disease activity, and growth velocity in patients with...

  16. Tailored PVA/ECM Scaffolds for Cartilage Regeneration

    Directory of Open Access Journals (Sweden)

    Elena Stocco

    2014-01-01

    Full Text Available Articular cartilage lesions are a particular challenge for regenerative medicine due to cartilage low self-ability repair in case of damage. Hence, a significant goal of musculoskeletal tissue engineering is the development of suitable structures in virtue of their matrix composition and biomechanical properties. The objective of our study was to design in vitro a supporting structure for autologous chondrocyte growth. We realized a biohybrid composite scaffold combining a novel and nonspecific extracellular matrix (ECM, which is decellularized Wharton’s jelly ECM, with the biomechanical properties of the synthetic hydrogel polyvinyl alcohol (PVA. Wharton’s jelly ECM was tested for its ability in promoting scaffold colonization by chondrocytes and compared with polyvinyl alcohol itself and the more specific decellularized cartilage matrix. Our preliminary evidences highlighted the chance of using Wharton’s jelly ECM in combination with PVA hydrogels as an innovative and easily available scaffold for cartilage restoration.

  17. Starch-modified magnetite nanoparticles for impregnation into cartilage

    International Nuclear Information System (INIS)

    The paper presents preparation and characterization of starch-modified Fe3O4 nanoparticles (NPs) in aqueous dispersion after impregnation into healthy and damaged types of cartilage. We show that starch-modified dispersion has a narrower size distribution than a non‐stabilized one. The average hydrodynamic radius of magnetite NPs in a dispersion used for impregnation into cartilage is (48 ± 1) nm with the width of the distribution from 5 to 200 nm. We investigate stability of aqueous magnetite NPs dispersions during storage and with increase in temperature (up to 70 °C). We find that polydisperse magnetite NPs can penetrate into cartilage and the size and concentration of impregnated particles depend on the organization of the tissue structure. The results confirm the possibility of application of magnetite NPs in diagnostics and laser treatment of degenerative cartilage deceases

  18. Analisis Pengaruh Receivable Turnover Ratio, Inventory Turnover Ratio, dan Total Assets Turnover Ratio Terhadap Earning Power pada Perusahaan Farmasi di Bursa Efek Indonesia

    OpenAIRE

    Bangun, Andri Primadana

    2011-01-01

    Tujuan dari penulisan skripsi ini adalah untuk menganalisis pengaruh rasio aktivitas dengan variabel Receivable Turnover Ratio, Inventory Turnover Ratio, dan Total Assets Turnover Ratio terhadap Earning Power perusasahaan farmasi dengan analisis regresi berganda. Jenis data yang akan diolah dan diteliti adalah data sekunder berupa laporan keuangan seperti neraca dan laporan laba-rugi serta bahan publikasi lain yang relevan dengan permasalahan yang diteliti. Tahun buku akuntansi yang dipili...

  19. Articular cartilage repair and the evolving role of regenerative medicine

    Directory of Open Access Journals (Sweden)

    Pieter K Bos

    2010-10-01

    Full Text Available Pieter K Bos1, Marloes L van Melle1, Gerjo JVM van Osch1,21Department of Orthopaedic Surgery, Erasmus MC, Rotterdam, the Netherlands; 2Department of Otorhinolaryngology, Erasmus MC, Rotterdam, the NetherlandsAbstract: Among the growing applications of regenerative medicine, clinical articular cartilage repair has now been used for 2 decades and forms a successful example of translational medicine. Cartilage is characterized by a limited intrinsic repair capacity following injury. Articular cartilage defects cause symptoms, are not spontaneously repaired, and are generally believed to result in early osteoarthritis. Marrow stimulation techniques, osteochondral transplantation, and cell-based therapies, such as autologous chondrocyte implantation (ACI and use of mesenchymal stem cells (MSCs, are used for tissue regeneration, symptom relief, and prevention of further joint degeneration. The exact incidence of cartilage defects and the natural outcome of joints with these lesions are unclear. Currently available cartilage repair techniques are designed for defect treatment in otherwise healthy joints and limbs, mostly in young adults. The natural history studies presented in this review estimated that the prevalence of cartilage lesions in this patient group ranges from 5% to 11%. The background and results from currently available randomized clinical trials of the three mostly used cartilage repair techniques are outlined in this review. Osteochondral transplantation, marrow stimulation, and ACI show improvement of symptoms with an advantage for cell-based techniques, but only a suggestion that risk for joint degeneration can be reduced. MSCs, characterized by their good proliferative capacity and the potential to differentiate into different mesenchymal lineages, form an attractive alternative cell source for cartilage regeneration. Moreover, MSCs provide a regenerative microenvironment by the secretion of bioactive factors. This trophic activity

  20. Post-traumatic glenohumeral cartilage lesions: a systematic review

    Directory of Open Access Journals (Sweden)

    Stussi Edgar

    2008-07-01

    Full Text Available Abstract Background Any cartilage damage to the glenohumeral joint should be avoided, as these damages may result in osteoarthritis of the shoulder. To understand the pathomechanism leading to shoulder cartilage damage, we conducted a systematic review on the subject of articular cartilage lesions caused by traumas where non impression fracture of the subchondral bone is present. Methods PubMed (MEDLINE, ScienceDirect (EMBASE, BIOBASE, BIOSIS Previews and the COCHRANE database of systematic reviews were systematically scanned using a defined search strategy to identify relevant articles in this field of research. First selection was done based on abstracts according to specific criteria, where the methodological quality in selected full text articles was assessed by two reviewers. Agreement between raters was investigated using percentage agreement and Cohen's Kappa statistic. The traumatic events were divided into two categories: 1 acute trauma which refers to any single impact situation which directly damages the articular cartilage, and 2 chronic trauma which means cartilage lesions due to overuse or disuse of the shoulder joint. Results The agreement on data quality between the two reviewers was 93% with a Kappa value of 0.79 indicating an agreement considered to be 'substantial'. It was found that acute trauma on the shoulder causes humeral articular cartilage to disrupt from the underlying bone. The pathomechanism is said to be due to compression or shearing, which can be caused by a sudden subluxation or dislocation. However, such impact lesions are rarely reported. In the case of chronic trauma glenohumeral cartilage degeneration is a result of overuse and is associated to other shoulder joint pathologies. In these latter cases it is the rotator cuff which is injured first. This can result in instability and consequent impingement which may progress to glenohumeral cartilage damage. Conclusion The great majority of glenohumeral cartilage

  1. Improved Visualization of Cartilage Canals Using Quantitative Susceptibility Mapping.

    Directory of Open Access Journals (Sweden)

    Mikko J Nissi

    Full Text Available Cartilage canal vessels are critical to the normal function of epiphyseal (growth cartilage and damage to these vessels is demonstrated or suspected in several important developmental orthopaedic diseases. High-resolution, three-dimensional (3-D visualization of cartilage canals has recently been demonstrated using susceptibility weighted imaging (SWI. In the present study, a quantitative susceptibility mapping (QSM approach is evaluated for 3-D visualization of the cartilage canals. It is hypothesized that QSM post-processing improves visualization of the cartilage canals by resolving artifacts present in the standard SWI post-processing while retaining sensitivity to the cartilage canals.Ex vivo distal femoral specimens from 3- and 8-week-old piglets and a 1-month-old human cadaver were scanned at 9.4 T with a 3-D gradient recalled echo sequence suitable for SWI and QSM post-processing. The human specimen and the stifle joint of a live, 3-week-old piglet also were scanned at 7.0 T. Datasets were processed using the standard SWI method and truncated k-space division QSM approach. To compare the post-processing methods, minimum/maximum intensity projections and 3-D reconstructions of the processed datasets were generated and evaluated.Cartilage canals were successfully visualized using both SWI and QSM approaches. The artifactual splitting of the cartilage canals that occurs due to the dipolar phase, which was present in the SWI post-processed data, was eliminated by the QSM approach. Thus, orientation-independent visualization and better localization of the cartilage canals was achieved with the QSM approach. Combination of GRE with a mask based on QSM data further improved visualization.Improved and artifact-free 3-D visualization of the cartilage canals was demonstrated by QSM processing of the data, especially by utilizing susceptibility data as an enhancing mask. Utilizing tissue-inherent contrast, this method allows noninvasive assessment

  2. Vulnerability of the Superficial Zone of Immature Articular Cartilage to Compressive Injury

    Energy Technology Data Exchange (ETDEWEB)

    Rolauffs, R.; Muehleman, C; Li, J; Kurz, B; Kuettner, K; Frank, E; Grodzinsky, A

    2010-01-01

    The zonal composition and functioning of adult articular cartilage causes depth-dependent responses to compressive injury. In immature cartilage, shear and compressive moduli as well as collagen and sulfated glycosaminoglycan (sGAG) content also vary with depth. However, there is little understanding of the depth-dependent damage caused by injury. Since injury to immature knee joints most often causes articular cartilage lesions, this study was undertaken to characterize the zonal dependence of biomechanical, biochemical, and matrix-associated changes caused by compressive injury. Disks from the superficial and deeper zones of bovine calves were biomechanically characterized. Injury to the disks was achieved by applying a final strain of 50% compression at 100%/second, followed by biomechanical recharacterization. Tissue compaction upon injury as well as sGAG density, sGAG loss, and biosynthesis were measured. Collagen fiber orientation and matrix damage were assessed using histology, diffraction-enhanced x-ray imaging, and texture analysis. Injured superficial zone disks showed surface disruption, tissue compaction by 20.3 {+-} 4.3% (mean {+-} SEM), and immediate biomechanical impairment that was revealed by a mean {+-} SEM decrease in dynamic stiffness to 7.1 {+-} 3.3% of the value before injury and equilibrium moduli that were below the level of detection. Tissue areas that appeared intact on histology showed clear textural alterations. Injured deeper zone disks showed collagen crimping but remained undamaged and biomechanically intact. Superficial zone disks did not lose sGAG immediately after injury, but lost 17.8 {+-} 1.4% of sGAG after 48 hours; deeper zone disks lost only 2.8 {+-} 0.3% of sGAG content. Biomechanical impairment was associated primarily with structural damage. The soft superficial zone of immature cartilage is vulnerable to compressive injury, causing superficial matrix disruption, extensive compaction, and textural alteration, which results

  3. The active form of MMP-3 is a marker of synovial inflammation and cartilage turnover in inflammatory joint diseases

    DEFF Research Database (Denmark)

    Sun, Shu; Bay-Jensen, Anne-Christine; Karsdal, Morten A;

    2014-01-01

    BACKGROUND: Matrix metalloproteinase-3 (MMP-3) plays an important role in the pathology of rheumatoid arthritis (RA) and ankylosing spondylitis (AS). Measurement of active MMP-3 in clinical samples could provide information about progression of rheumatoid diseases, and potentially response to tre...

  4. MMP Induction by Relaxin Causes Cartilage Matrix Degradation in Target Synovial Joints: Receptor Profiles Correlate with Matrix Turnover

    OpenAIRE

    Kapila, Sunil; Wang, Wei; Uston, Karen

    2009-01-01

    Our long-term goal is to understand the mechanisms by which relaxin and estrogen potentially contribute to joint diseases particularly those afflicting the fibrocartilaginous temporomandibular joint (TMJ). Previously, we showed that relaxin produces a dose-dependent induction of tissue degrading enzymes of the matrix metalloproteinase (MMP) family, specifically MMP-1 (collagenase-1), −3 (stromelysin-1), −9 (92-kDa-gelatinase) and −13 (collagenase-3) in cell isolates and tissue explants from T...

  5. CEO turnover and relative performance evaluation

    OpenAIRE

    Jenter, Dirk; Kanaan, Fadi

    2015-01-01

    This paper examines whether CEOs are fired after bad firm performance caused by factors beyond their control. Standard economic theory predicts that corporate boards filter out exogenous industry and market shocks to firm performance when deciding on CEO retention. Using a new hand-collected sample of 1,590 CEO turnovers from 1993 to 2001, we document that CEOs are significantly more likely to be dismissed from their jobs after bad industry and bad market performance. A decline in the industr...

  6. Stock Option Compensation and Managerial Turnover

    OpenAIRE

    Raluca Georgiana NASTASESCU

    2009-01-01

    This study examines the association between managerial turnover and equity-based compensation. I investigate whether stock options act to bond executives to their firms and whether retention of managers is a motivation of companies in designing CEO incentive contracts. The results show that stock options do negatively influence the probability of a CEO leaving the company. The monetary cost of losing the value of equity-based compensation package keeps the manager with his company. I also fin...

  7. Unemployment Insurance and Job Turnover in Spain

    OpenAIRE

    Yolanda Rebollo Sanz

    2010-01-01

    The aim of this paper is to shed some light on the potential relationships between the unemployment insurance system and labour market turnover, seeking to further the traditional view that this system has only behavioural consequences for the labour supply side of the labour market. This study assumes the incentives embedded in the unemployment insurance system have a heterogeneous impact, depending on the type of labour market transition (quits versus layoffs and recalls versus new job entr...

  8. Systems turnover activities at NPP-Cernavoda

    International Nuclear Information System (INIS)

    The erection of a nuclear power plant requires the utilisation of complex Quality Assurance (QA) programs. These programs implement specific standards, procedures and laws to ensure that the plant is constructed to the highest possible safety level attainable. Some procedures and standards have a narrow field of action while others cover a large area of operation. Such is the case with the turnover procedure presented in this paper, which is one component of the QA program. (Author)

  9. Job Turnover Unemployment and Labor Market Institutions

    OpenAIRE

    Gilles JOSEPH; Olivier PIERRARD; Sneessens, Henri

    2003-01-01

    This paper studies the role of labor market institutions on unemployment and on the cyclical properties of job flows. We construct an intertemporal general equilib- rium model with search unemployment and endogenous job turnover, and examine the consequences of introducing an unemployment benefit, a firing cost and a downward wage rigidity. The model is able to reproduce the main cyclical properties of a typical European economy. It also suggests that downward wage rigidities, ...

  10. Wage policy, employee turnover and productivity

    OpenAIRE

    Arnaud Chevalier; W.S. Siebert; Tarja Viitanen

    2003-01-01

    In this paper, we are interested in the effect of pay incentives on labour turnover and productivity. Particularly we use personnel data from a panel of 400 shops from a UK retail chain. The firm uses perfectly flat hourly wage system with no reward for tenure or individual productivity. This system leads to the phenomenon of negative selection, where only employees with lower outside options remain with the firm. We show that negative selection conflicts with human capital so that the relati...

  11. Equilibrium labour turnover, firm growth and unemployment

    OpenAIRE

    Coles, Melvyn G; Dale T. Mortensen

    2012-01-01

    This paper identifies a data-consistent, equilibrium model of unemployment, wage dispersion, quit turnover and firm growth dynamics. In a separating equilibrium, more productive firms signal their type by paying strictly higher wages in every state of the market. Workers optimally quit to firms paying a higher wage and so move effciently from less to more productive firms. Start-up firms are initially small and grow endogenously over time. Consistent with Gibrat's law, individual firm growth ...

  12. Wage policy, employee turnover and productivity

    OpenAIRE

    Chevalier, Arnaud; W.S. Siebert; Viitanen, Tarja

    2003-01-01

    In this paper, we are interested in the effect of pay incentives on labour turnover and productivity. Particularly we use personnel data from a panel of 400 shops from a UK retail chain. The firm uses perfectly flat hourly wage system with no reward for tenure or individual productivity. This system leads to the phenomenon of negative selection, where only employees with lower outside options remain with the firm. We show that negative selection conflicts with human capital so that the re...

  13. Leadership, Perceptions, and Turnover Intentions: Why Stay?

    OpenAIRE

    Nelson, Joel A.; Daniels, Michael K.

    2014-01-01

    The purpose of the quantitative correlational study was to highlight the variable relationships between tenure, perceptions, job satisfaction, and turnover intentions for a sample consisting of individuals working for managers who were previously peers. The study incorporated a quantitative correlational structure and the rationale for choosing the structure for the initiative was to aid in the analysis of sample data gathered using Likert-type surveying tools regarding the variables chosen f...

  14. High bone turnover in Irish professional jockeys.

    LENUS (Irish Health Repository)

    Waldron-Lynch, F

    2012-02-01

    SUMMARY: Professional jockeys are routinely exposed to high impact trauma and sustain fractures frequently. We found that jockeys restrict their caloric intake in order to maintain regulation weights, and that bone turnover is high. There are significant health and safety implications for the racing industry. INTRODUCTION: Professional jockeys routinely sustain fractures from high impact falls. Jockeys maintain a low percentage body fat and a low body mass index (BMI) to achieve low weight targets in order to race. We evaluated dietary habits and bone metabolism in jockeys. METHODS: Bone mineral density (BMD) was measured in 27 male jockeys of the 144 jockeys licensed in Ireland. Fourteen (52%) had BMD T score below -1.0, of whom 12 consented to clinical review, nutritional survey, endocrine studies, and bone turnover markers (BTM). BTM were compared to age- and sex-matched controls (n = 16). RESULTS: BMI was 20.6 +\\/- 1.7 kg\\/m(2); previous fracture frequency was 3.2 +\\/- 2.0 per rider. All had normal endocrine axes. The jockeys\\' diet as determined by a 7-day dietary recall was deficient in energy, calcium, and vitamin D intake. Compared with the control group, the jockey group had evidence of increased bone turnover. CONCLUSIONS: A substantial proportion of the professional jockeys in Ireland have low-normal BMD, low BMI, and high bone turnover that may result from weight and dietary restrictions. These factors seem to have a deleterious effect on their bone health and predispose the jockeys to a high fracture risk that should be remediated.

  15. PERAN STRES KERJA DAN KEPUASAN KERJA UNTUK MENGURANGI TURNOVER INTENTION

    Directory of Open Access Journals (Sweden)

    Syarifah Nazenin

    2014-09-01

    Full Text Available Tujuan penelitian ini untuk menguji pengaruh variabel stres kerja dan kepuasan kerja pada turnover intention karyawan tetap bagian produksi. Sampel penelitian ini adalah 86 responden, menggunakan metode Slovin dengan teknik probability sampling dengan jenis proportionate random sampling. Berdasarkan hasil penelitian, menunjukkan bahwa stres kerja berpengaruh positif signifikan pada turnover intention. Kemudian, kepuasan kerja berpengaruh negatif signifikan. Penelitian ini menyimpulkan, bahwa stres kerja berpengaruh positif dan signifikan pada turnover intention karyawan dan kepuasan kerja berpengaruh negatif dan signifikan terhadap turnover intention karyawan. Implikasi manajerial yang bisa dilakukan adalah dengan pengurangan tingkat stres karyawan dan membuat program untuk tujuan menekan turnover intention, seperti kesempatan promosi dan meningkatkan reward karyawan. The purpose of this study conducted to examine the effect of work stress and job satisfaction on turnover intention of employee in production department. The sample was 86 respondent, using Slovin method with proportionate random sampling technique. The result showed that job stress has a positive effect on turnover intention while job satisfaction has a negative effect on turnover intention. This study conclude that job stress has positive and significant impact on employee turnover intention and job satisfaction significantly and negatively related to turnover intention of employees. Therefore, it is recommended to managerial level people to reduce stress levels in employees and to create a program for pressing turnover intention, such as promotional opportunities and improve employee rewards.

  16. Comparative digital cartilage histology for human and common osteoarthritis models

    OpenAIRE

    Pedersen DR; Goetz JE; Kurriger GL; Martin JA

    2013-01-01

    Douglas R Pedersen, Jessica E Goetz, Gail L Kurriger, James A MartinDepartment of Orthopaedics and Rehabilitation, University of Iowa, Iowa City, IA, USAPurpose: This study addresses the species-specific and site-specific details of weight-bearing articular cartilage zone depths and chondrocyte distributions among humans and common osteoarthritis (OA) animal models using contemporary digital imaging tools. Histological analysis is the gold-standard research tool for evaluating cartilage healt...

  17. Nanomechanical phenotype of chondroadherin-null murine articular cartilage.

    Science.gov (United States)

    Batista, Michael A; Nia, Hadi T; Önnerfjord, Patrik; Cox, Karen A; Ortiz, Christine; Grodzinsky, Alan J; Heinegård, Dick; Han, Lin

    2014-09-01

    Chondroadherin (CHAD), a class IV small leucine rich proteoglycan/protein (SLRP), was hypothesized to play important roles in regulating chondrocyte signaling and cartilage homeostasis. However, its roles in cartilage development and function are not well understood, and no major osteoarthritis-like phenotype was found in the murine model with CHAD genetically deleted (CHAD(-/-)). In this study, we used atomic force microscopy (AFM)-based nanoindentation to quantify the effects of CHAD deletion on changes in the biomechanical function of murine cartilage. In comparison to wild-type (WT) mice, CHAD-deletion resulted in a significant ≈70-80% reduction in the indentation modulus, Eind, of the superficial zone knee cartilage of 11 weeks, 4 months and 1 year old animals. This mechanical phenotype correlates well with observed increases in the heterogeneity collagen fibril diameters in the surface zone. The results suggest that CHAD mainly plays a major role in regulating the formation of the collagen fibrillar network during the early skeletal development. In contrast, CHAD-deletion had no appreciable effects on the indentation mechanics of middle/deep zone cartilage, likely due to the dominating role of aggrecan in the middle/deep zone. The presence of significant rate dependence of the indentation stiffness in both WT and CHAD(-/-) knee cartilage suggested the importance of both fluid flow induced poroelasticity and intrinsic viscoelasticity in murine cartilage biomechanical properties. Furthermore, the marked differences in the nanomechanical behavior of WT versus CHAD(-/-) cartilage contrasted sharply with the relative absence of overt differences in histological appearance. These observations highlight the sensitivity of nanomechanical tools in evaluating structural and mechanical phenotypes in transgenic mice. PMID:24892719

  18. Quantitative spatially resolved measurements of mass transfer through laryngeal cartilage.

    Science.gov (United States)

    Macpherson, J V; O'Hare, D; Unwin, P R; Winlove, C P

    1997-11-01

    The scanning electrochemical microscope (SECM) is a scanned probe microscope that uses the response of a mobile ultramicroelectrode (UME) tip to determine the reactivity, topography, and mass transport characteristics of interfaces with high spatial resolution. SECM strategies for measuring the rates of solute diffusion and convection through samples of cartilage, using amperometric UMEs, are outlined. The methods are used to determine the diffusion coefficients of oxygen and ruthenium(III) hexamine [Ru(NH3)6(3+)] in laryngeal cartilage. The diffusion coefficient of oxygen in cartilage is found to be approximately 50% of that in aqueous electrolyte solution, assuming a partition coefficient of unity for oxygen between cartilage and aqueous solution. In contrast, diffusion of Ru(NH3)6(3+) within the cartilage sample cannot be detected on the SECM timescale, suggesting a diffusion coefficient at least two orders of magnitude lower than that in solution, given a measured partition coefficient for Ru(NH3)6(3+) between cartilage and aqueous solution, Kp = [Ru(NH3)6(3+)]cartilage/[RU(NH3)6(3+)]solution = 3.4 +/- 0.1. Rates of Ru(NH3)6(3+) osmotically driven convective transport across cartilage samples are imaged at high spatial resolution by monitoring the current response of a scanning UME, with an osmotic pressure of approximately 0.75 atm across the slice. A model is outlined that enables the current response to be related to the local flux. By determining the topography of the sample from the current response with no applied osmotic pressure, local transport rates can be correlated with topographical features of the sample surface, at much higher spatial resolution than has previously been achieved. PMID:9370471

  19. In Vitro Engineering of High Modulus Cartilage-Like Constructs

    OpenAIRE

    Finlay, Scott; Seedhom, Bahaa B.; Carey, Duane O.; Bulpitt, Andy J.; Treanor, Darren E.; Kirkham, Jennifer

    2016-01-01

    To date, the outcomes of cartilage repair have been inconsistent and have frequently yielded mechanically inferior fibrocartilage, thereby increasing the chances of damage recurrence. Implantation of constructs with biochemical composition and mechanical properties comparable to natural cartilage could be advantageous for long-term repair. This study attempted to create such constructs, in vitro, using tissue engineering principles. Bovine synoviocytes were seeded on nonwoven polyethylene ter...

  20. Resurfacing Damaged Articular Cartilage to Restore Compressive Properties

    OpenAIRE

    Grenier, Stephanie; Donnelly, Patrick E; Gittens, Jamila; Torzilli, Peter A.

    2014-01-01

    Surface damage to articular cartilage is recognized as the initial underlying process causing the loss of mechanical function in early-stage osteoarthritis. In this study, we developed structure-modifying treatments to potentially prevent, stabilize or reverse the loss in mechanical function. Various polymers (chondroitin sulfate, carboxymethylcellulose, sodium hyaluronate) and photoinitiators (riboflavin, irgacure 2959) were applied to the surface of collagenase-degraded cartilage and crossl...

  1. Reducing the morbidity involved in harvesting autogenous rib cartilage.

    Science.gov (United States)

    Siegert, Ralf; Magritz, Ralph

    2009-08-01

    Although the use of autogenous cartilage is the gold standard in auricular reconstruction, its main disadvantage is the morbidity due to harvesting the cartilage. This includes postoperative pain, visible scar, and possibly asymmetry and reduced stability of the thorax. To reduce all of these drawbacks, we describe some modifications that reduce pain to a low tolerable level, hide the scar invisibly in the submammary fold in females, and induce regeneration as well reestablish stability of the rib defect. PMID:19809948

  2. Comparative digital cartilage histology for human and common osteoarthritis models

    Directory of Open Access Journals (Sweden)

    Pedersen DR

    2013-02-01

    Full Text Available Douglas R Pedersen, Jessica E Goetz, Gail L Kurriger, James A MartinDepartment of Orthopaedics and Rehabilitation, University of Iowa, Iowa City, IA, USAPurpose: This study addresses the species-specific and site-specific details of weight-bearing articular cartilage zone depths and chondrocyte distributions among humans and common osteoarthritis (OA animal models using contemporary digital imaging tools. Histological analysis is the gold-standard research tool for evaluating cartilage health, OA severity, and treatment efficacy. Historically, evaluations were made by expert analysts. However, state-of-the-art tools have been developed that allow for digitization of entire histological sections for computer-aided analysis. Large volumes of common digital cartilage metrics directly complement elucidation of trends in OA inducement and concomitant potential treatments.Materials and methods: Sixteen fresh human knees, 26 adult New Zealand rabbit stifles, and 104 bovine lateral plateaus were measured for four cartilage zones and the cell densities within each zone. Each knee was divided into four weight-bearing sites: the medial and lateral plateaus and femoral condyles.Results: One-way analysis of variance followed by pairwise multiple comparisons (Holm–Sidak method at a significance of 0.05 clearly confirmed the variability between cartilage depths at each site, between sites in the same species, and between weight-bearing articular cartilage definitions in different species.Conclusion: The present study clearly demonstrates multisite, multispecies differences in normal weight-bearing articular cartilage, which can be objectively quantified by a common digital histology imaging technique. The clear site-specific differences in normal cartilage must be taken into consideration when characterizing the pathoetiology of OA models. Together, these provide a path to consistently analyze the volume and variety of histologic slides necessarily generated

  3. Generational differences in registered nurse turnover.

    Science.gov (United States)

    LeVasseur, Sandra A; Wang, Chen-Yen; Mathews, Barbara; Boland, Mary

    2009-08-01

    The chronic nature of the nursing workforce shortage in the United States is a continuing concern. As the nationwide gap between supply and demand grows, it remains unknown what impact turnover will have on nursing, access to care, and efforts to improve quality and safety of health care. It also remains unclear whether the recent turnover trends among new graduate registered nurses differ from past generational cohorts of new nurses. The aims of this study were to identify the reasons why registered nurses turnover by generational cohort (Veterans, Baby Boomers, and GenXMs) and to compare the length of time nurses were employed in their first five nursing positions by generational cohort. The findings suggest the three generational cohorts displayed similar reasons for leaving nursing positions with relocation, career advancement, and personal/family reasons reported most frequently. Except for the first nursing position, significant generational effects were found in the length of time Veterans, Baby Boomer, and GenXMs stayed employed in their nursing positions. It remains unknown why the GenXMs displayed a significantly shorter length of employment time in their second, third, fourth, and fifth nursing positions. The decline in length of employment time displayed in both the Baby Boomers and GenXMs may be an issue of concern requiring future research. PMID:20026454

  4. The Role of Sirtuins in Cartilage Homeostasis and Osteoarthritis.

    Science.gov (United States)

    Dvir-Ginzberg, Mona; Mobasheri, Ali; Kumar, Ashok

    2016-07-01

    The past decade has witnessed many advances in the understanding of sirtuin biology and related regulatory circuits supporting the capacity of these proteins to serve as energy-sensing molecules that contribute to healthspan in various tissues, including articular cartilage. Hence, there has been a significant increase in new investigations that aim to elucidate the mechanisms of sirtuin function and their roles in cartilage biology, skeletal development, and pathologies such as osteoarthritis (OA), rheumatoid arthritis (RA), and intervertebral disc degeneration (IVD). The majority of the work carried out to date has focused on SIRT1, although SIRT6 has more recently become a focus of some investigations. In vivo work with transgenic mice has shown that Sirt1 and Sirt6 are essential for maintaining cartilage homeostasis and that the use of sirtuin-activating molecules such as resveratrol may have beneficial effects on cartilage anabolism. Current thinking is that SIRT1 exerts positive effects on cartilage by encouraging chondrocyte survival, especially under stress conditions, which may provide a mechanism supporting the use of sirtuin small-molecule activators (STACS) for future therapeutic interventions in OA and other degenerative pathologies of joints, especially those that involve articular cartilage. PMID:27289467

  5. In Vitro Engineering of High Modulus Cartilage-Like Constructs.

    Science.gov (United States)

    Finlay, Scott; Seedhom, Bahaa B; Carey, Duane O; Bulpitt, Andy J; Treanor, Darren E; Kirkham, Jennifer

    2016-04-01

    To date, the outcomes of cartilage repair have been inconsistent and have frequently yielded mechanically inferior fibrocartilage, thereby increasing the chances of damage recurrence. Implantation of constructs with biochemical composition and mechanical properties comparable to natural cartilage could be advantageous for long-term repair. This study attempted to create such constructs, in vitro, using tissue engineering principles. Bovine synoviocytes were seeded on nonwoven polyethylene terephthalate fiber scaffolds and cultured in chondrogenic medium for 4 weeks, after which uniaxial compressive loading was applied using an in-house bioreactor for 1 h per day, at a frequency of 1 Hz, for a further 84 days. The initial loading conditions, determined from the mechanical properties of the immature constructs after 4 weeks in chondrogenic culture, were strains ranging between 13% and 23%. After 56 days (sustained at 84 days) of loading, the constructs were stained homogenously with Alcian blue and for type-II collagen. Dynamic compressive moduli were comparable to the high end values for native cartilage and proportional to Alcian blue staining intensity. We suggest that these high moduli values were attributable to the bioreactor setup, which caused the loading regime to change as the constructs developed, that is, the applied stress and strain increased with construct thickness and stiffness, providing continued sufficient cell stimulation as further matrix was deposited. Constructs containing cartilage-like matrix with response to load similar to that of native cartilage could produce long-term effective cartilage repair when implanted. PMID:26850081

  6. In Vitro Engineering of High Modulus Cartilage-Like Constructs

    Science.gov (United States)

    Seedhom, Bahaa B.; Carey, Duane O.; Bulpitt, Andy J.; Treanor, Darren E.; Kirkham, Jennifer

    2016-01-01

    To date, the outcomes of cartilage repair have been inconsistent and have frequently yielded mechanically inferior fibrocartilage, thereby increasing the chances of damage recurrence. Implantation of constructs with biochemical composition and mechanical properties comparable to natural cartilage could be advantageous for long-term repair. This study attempted to create such constructs, in vitro, using tissue engineering principles. Bovine synoviocytes were seeded on nonwoven polyethylene terephthalate fiber scaffolds and cultured in chondrogenic medium for 4 weeks, after which uniaxial compressive loading was applied using an in-house bioreactor for 1 h per day, at a frequency of 1 Hz, for a further 84 days. The initial loading conditions, determined from the mechanical properties of the immature constructs after 4 weeks in chondrogenic culture, were strains ranging between 13% and 23%. After 56 days (sustained at 84 days) of loading, the constructs were stained homogenously with Alcian blue and for type-II collagen. Dynamic compressive moduli were comparable to the high end values for native cartilage and proportional to Alcian blue staining intensity. We suggest that these high moduli values were attributable to the bioreactor setup, which caused the loading regime to change as the constructs developed, that is, the applied stress and strain increased with construct thickness and stiffness, providing continued sufficient cell stimulation as further matrix was deposited. Constructs containing cartilage-like matrix with response to load similar to that of native cartilage could produce long-term effective cartilage repair when implanted. PMID:26850081

  7. Colonies in engineered articular cartilage express superior differentiation.

    Science.gov (United States)

    Selvaratnam, L; Abd Rahim, S; Kamarul, T; Chan, K Y; Sureshan, S; Penafort, R; Ng, C L L

    2005-07-01

    In view of poor regeneration potential of the articular cartilage, in-vitro engineering of cartilage tissue offers a promising option for progressive joint disease. This study aims to develop a biologically engineered articular cartilage for autologous transplantation. The initial work involved determination of chondrocyte yield and viability, and morphological analysis. Cartilage was harvested from the knee, hip and shoulder joints of adult New Zealand white rabbits and chondrocytes were isolated by enzymatic digestion of the extra-cellular matrix before serial cultivation in DMEM/Ham's F12 media as monolayer cultures. No differences were noted in cell yield. Although chondrocytes viability was optimal (>93%) following harvest from native cartilage, their viability tended to be lowered on passaging. Chondrocytes aggregated in isogenous colonies comprising ovoid cells with intimate intracellular contacts and readily exhibited Safranin-O positive matrix; features typically associated with articular cartilage in-vivo. However, chondrocytes also existed concurrently in scattered bipolar/multipolar forms lacking Safranin-O expression. Therefore, early data demonstrated successful serial culture of adult chondrocytes with differentiated morphology seen in established chondrocyte colonies synthesizing matrix proteoglycans. PMID:16381284

  8. Validity of echographic evaluation of cartilage in gonarthrosis. Preliminary report.

    Science.gov (United States)

    Martino, F; Ettorre, G C; Angelelli, G; Macarini, L; Patella, V; Moretti, B; D'Amore, M; Cantatore, F P

    1993-06-01

    We studied an echographic technique by which precise reproducible measurements of articular cartilage thickness of the knee is possible. Two groups of individuals were studied: a group of 18 patients with gonarthrosis and a control group of 10 normal individuals. The group of 18 patients with gonarthrosis was studied by ultrasound (US) before knee prosthesis surgery. The cartilage thickness was measured within the weight-bearing area. US re-evaluation and histological measurements were made on the pathological specimen following the operation. Results of pre- and post-operative US data were compared with histological data. A good correlation between these measurements was found [P(t) > 10%]. In order to have comparative reference values of the articular cartilage within the weight-bearing area of the femoral trochlea a group of 10 control subjects was also studied with US as above. We found that the articular cartilage thickness of the femoral trochlea in the weight-bearing area has a mean of 2.2 +/- 0.3 mm for the lateral condyle and 2.3 +/- 0.2 mm for the medial condyle. The intra-observer and inter-observer difference in measurements was evaluated with Student's t-test. Our data demonstrate that US measurements of articular cartilage thickness of femoral condyles is a sensitive and reproducible technique which permits early diagnosis and management of knee arthropathy as well as quantification of cartilage damage. PMID:8358975

  9. CCN1 Regulates Chondrocyte Maturation and Cartilage Development.

    Science.gov (United States)

    Zhang, Yongchun; Sheu, Tzong-Jen; Hoak, Donna; Shen, Jie; Hilton, Matthew J; Zuscik, Michael J; Jonason, Jennifer H; O'Keefe, Regis J

    2016-03-01

    WNT/β-CATENIN signaling is involved in multiple aspects of skeletal development, including chondrocyte differentiation and maturation. Although the functions of β-CATENIN in chondrocytes have been extensively investigated through gain-of-function and loss-of-function mouse models, the precise downstream effectors through which β-CATENIN regulates these processes are not well defined. Here, we report that the matricellular protein, CCN1, is induced by WNT/β-CATENIN signaling in chondrocytes. Specifically, we found that β-CATENIN signaling promotes CCN1 expression in isolated primary sternal chondrocytes and both embryonic and postnatal cartilage. Additionally, we show that, in vitro, CCN1 overexpression promotes chondrocyte maturation, whereas inhibition of endogenous CCN1 function inhibits maturation. To explore the role of CCN1 on cartilage development and homeostasis in vivo, we generated a novel transgenic mouse model for conditional Ccn1 overexpression and show that cartilage-specific CCN1 overexpression leads to chondrodysplasia during development and cartilage degeneration in adult mice. Finally, we demonstrate that CCN1 expression increases in mouse knee joint tissues after meniscal/ligamentous injury (MLI) and in human cartilage after meniscal tear. Collectively, our data suggest that CCN1 is an important regulator of chondrocyte maturation during cartilage development and homeostasis. © 2015 American Society for Bone and Mineral Research. PMID:26363286

  10. Image processing techniques for noise removal, enhancement and segmentation of cartilage OCT images

    International Nuclear Information System (INIS)

    Osteoarthritis, whose hallmark is the progressive loss of joint cartilage, is a major cause of morbidity worldwide. Recently, optical coherence tomography (OCT) has demonstrated considerable promise for the assessment of articular cartilage. Among the most important parameters to be assessed is cartilage width. However, detection of the bone cartilage interface is critical for the assessment of cartilage width. At present, the quantitative evaluations of cartilage thickness are being done using manual tracing of cartilage-bone borders. Since data is being obtained near video rate with OCT, automated identification of the bone-cartilage interface is critical. In order to automate the process of boundary detection on OCT images, there is a need for developing new image processing techniques. In this paper we describe the image processing techniques for speckle removal, image enhancement and segmentation of cartilage OCT images. In particular, this paper focuses on rabbit cartilage since this is an important animal model for testing both chondroprotective agents and cartilage repair techniques. In this study, a variety of techniques were examined. Ultimately, by combining an adaptive filtering technique with edge detection (vertical gradient, Sobel edge detection), cartilage edges can be detected. The procedure requires several steps and can be automated. Once the cartilage edges are outlined, the cartilage thickness can be measured. (author)

  11. Bone cysts after osteochondral allograft repair of cartilage defects in goats suggest abnormal interaction between subchondral bone and overlying synovial joint tissues.

    Science.gov (United States)

    Pallante-Kichura, Andrea L; Cory, Esther; Bugbee, William D; Sah, Robert L

    2013-11-01

    The efficacy of osteochondral allografts (OCAs) may be affected by osseous support of the articular cartilage, and thus affected by bone healing and remodeling in the OCA and surrounding host. Bone cysts, and their communication pathways, may be present in various locations after OCA insertion and reflect distinct pathogenic mechanisms. Previously, we analyzed the effect of OCA storage (FRESH, 4°C/14d, 4°C/28d, FROZEN) on cartilage quality in fifteen adult goats after 12months in vivo. The objectives of this study were to further analyze OCAs and contralateral non-operated (Non-Op) CONTROLS from the medial femoral condyle to (1) determine the effect of OCA storage on local subchondral bone (ScB) and trabecular bone (TB) structure, (2) characterize the location and structure of bone cysts and channels, and (3) assess the relationship between cartilage and bone properties. (1) Overall bone structure after OCAs was altered compared to Non-Op, with OCA samples displaying bone cysts, ScB channels, and ScB roughening. ScB BV/TV in FROZEN OCAs was lower than Non-Op and other OCAs. TB BV/TV in FRESH, 4°C/14d, and 4°C/28d OCAs did not vary compared to Non-Op, but BS/TV was lower. (2) OCAs contained "basal" cysts, localized to deeper regions, some "subchondral" cysts, localized near the bone-cartilage interface, and some ScB channels. TB surrounding basal cysts exhibited higher BV/TV than Non-Op. (3) Basal cysts occurred (a) in isolation, (b) with subchondral cysts and ScB channels, (c) with ScB channels, or (d) with subchondral cysts, ScB channels, and ScB erosion. Deterioration of cartilage gross morphology was strongly associated with abnormal μCT bone structure. Evidence of cartilage-bone communication following OCA repair may favor fluid intrusion as a mechanism for subchondral cyst formation, while bone resorption at the graft-host interface without affecting overall bone and cartilage structure may favor bony contusion mechanism for basal cyst formation. These

  12. Does cartilage volume measurement or radiographic osteoarthritis at baseline independently predict ten-year cartilage volume loss?

    OpenAIRE

    McBride, Andrew; Khan, Hussain Ijaz; Aitken, Dawn; Chou, Louisa; Ding, Changhai; Blizzard, Leigh; Pelletier, Jean-Pierre; Martel-Pelletier, Johanne; Cicuttini, Flavia; Jones, Graeme

    2016-01-01

    Background The aim of this study was to examine whether cartilage volume as measured by MRI and radiographic osteoarthritis (OA) at baseline predict cartilage volume loss over ten years independent of each other and other structural co-pathologies. Methods 219 participants [mean-age 45(26–61); 57 % female] were studied at baseline and ten years. Approximately half were the adult offspring of subjects who underwent knee replacement for OA and the remainder were randomly selected controls. Join...

  13. Plasma transthyretin. Tissue sites of degradation and turnover in the rat

    International Nuclear Information System (INIS)

    Transthyretin (TTR) is involved in the plasma transport of both retinol and thyroid hormones. TTR is synthesized in the liver and choroid plexus, and in small amounts in several other tissues. A study was conducted to determine the tissue sites of degradation and turnover of TTR in the rat. The study employed TTR labeled with tyramine cellobiose (TC) and the trapped ligand method. Samples of purified rat TTR were labeled either with 125I-TC or directly with 131I. A mixture of the two labeled TTRs was injected intravenously into six rats. Blood samples were collected via a venous catheter for kinetic (turnover) analysis. After 24 or 48 h, the rats were killed, and 23 different tissues/organs were assayed as possible sites of TTR degradation. Derivatization of TTR with TC did not appreciably alter TTR plasma kinetics. Plasma turnover data were best fit by a three-pool model. The mean fractional turnover of plasma TTR was 0.15/h, and of total body TTR 0.04/h. The major sites of TTR degradation were the liver (36-38% of total body TTR degradation, almost all in hepatocytes), muscle (12-15%), and skin (8-10%). Tissues that were sites of 1-8% of body TTR degradation included kidneys, adipose tissue, testes, and the gastrointestinal tract. Less than 1% of total TTR degradation occurred in the other tissues examined. A second study was conducted in which labeled TTR was injected intraventricularly into the cerebrospinal fluid in order to explore the degradation of TTR of choroid plexus origin. The kinetics of the appearance and disappearance of such labeled TTR in plasma were physiologically reasonable, with an estimated turnover of cerebrospinal fluid TTR of the order of 0.33/h. The major tissue sites of degradation of labeled TTR injected into cerebrospinal fluid and into plasma were approximately the same

  14. Correlation between Focal Nodular Low Signal Changes in Hoffa's Fat Pad Adjacent to Anterior Femoral Cartilage and Focal Cartilage Defect Underlying This Region and Its Possible Implication

    Science.gov (United States)

    Ng, Wuey Min

    2016-01-01

    Purpose. This study investigates the association between focal nodular mass with low signal in Hoffa's fat pad adjacent to anterior femoral cartilage of the knee (FNMHF) and focal cartilage abnormality in this region. Method. The magnetic resonance fast imaging employing steady-state acquisition sequence (MR FIESTA) sagittal and axial images of the B1 and C1 region (described later) of 148 patients were independently evaluated by two reviewers and categorized into four categories: normal, FNMHF with underlying focal cartilage abnormality, FNMHF with normal cartilage, and cartilage abnormality with no FNMHF. Results. There was a significant association (p = 0.00) between FNMHF and immediate adjacent focal cartilage abnormality with high interobserver agreement. The absence of focal nodular lesions next to the anterior femoral cartilage has a very high negative predictive value for chondral injury (97.8%). Synovial biopsy of focal nodular lesion done during arthroscopy revealed some fibrocollagenous tissue and no inflammatory cells. Conclusion. We postulate that the FNMHF adjacent to the cartilage defects is a form of normal healing response to the cartilage damage. One patient with FHMHF and underlying cartilage abnormality was rescanned six months later. In this patient, the FNMHF disappeared and normal cartilage was observed in the adjacent region which may support this theory.

  15. Nasal reconstruction with articulated irradiated rib cartilage

    International Nuclear Information System (INIS)

    Nasal structural reconstruction is a formidable task in cases where there is loss of support to both the nasal dorsum and tip. A multitude of surgical approaches and materials have been used for the correction of the saddle-nose deformity with varying degrees of success. Articulated irradiated rib cartilage inserted through an external rhinoplasty approach was used to reconstruct nasal deformities in 18 patients over a 6-year period. Simultaneous use of a midline forehead flap to reconstruct the overlying soft tissue was required in four cases. Follow-up ranged from 1 to 6 years (mean, 2.8 years). Results were rewarding in most cases with marked improvement in nasal support and airway. Revision and/or replacement secondary to trauma or warping of the graft was required in four cases. None of the patients exhibited infection, extrusion, or noticeable resorption. A description of the surgical technique, review of all the cases, and recommendation for continued use of this graft material are discussed

  16. Nasal reconstruction with articulated irradiated rib cartilage

    Energy Technology Data Exchange (ETDEWEB)

    Murakami, C.S.; Cook, T.A.; Guida, R.A. (Univ. of Washington School of Medicine, Seattle (USA))

    1991-03-01

    Nasal structural reconstruction is a formidable task in cases where there is loss of support to both the nasal dorsum and tip. A multitude of surgical approaches and materials have been used for the correction of the saddle-nose deformity with varying degrees of success. Articulated irradiated rib cartilage inserted through an external rhinoplasty approach was used to reconstruct nasal deformities in 18 patients over a 6-year period. Simultaneous use of a midline forehead flap to reconstruct the overlying soft tissue was required in four cases. Follow-up ranged from 1 to 6 years (mean, 2.8 years). Results were rewarding in most cases with marked improvement in nasal support and airway. Revision and/or replacement secondary to trauma or warping of the graft was required in four cases. None of the patients exhibited infection, extrusion, or noticeable resorption. A description of the surgical technique, review of all the cases, and recommendation for continued use of this graft material are discussed.

  17. Noninvasive determination of knee cartilage deformation during jumping.

    Science.gov (United States)

    Filipovic, Nenad; Vulovic, Radun; Peulic, Aleksandar; Radakovic, Radivoje; Kosanic, Djordje; Ristic, Branko

    2009-01-01

    The purpose of this investigation was to use a combination of image processing, force measurements and finite element modeling to calculate deformation of the knee cartilage during jumping. Professional athletes performed jumps analyzed using a force plate and high-speed video camera system. Image processing was performed on each frame of video using a color recognition algorithm. A simplified mass-spring-damper model was utilized for determination of global force and moment on the knee. Custom software for fitting the coupling characteristics was created. Simulated results were used as input data for the finite element calculation of cartilage deformation in the athlete's knee. Computer simulation data was compared with the average experimental ground reaction forces. The results show the three-dimensional mechanical deformation distribution inside the cartilage volume. A combination of the image recognition technology, force plate measurements and the finite element cartilage deformation in the knee may be used in the future as an effective noninvasive tool for prediction of injury during jumping. Key pointsEven there are many existing mathematical models of force distribution during running or jumping (Liu et al, 1998), to our knowledge there is no interdisciplinary approach where imaging processing, finite element modeling and experimental force plate system are employed.The aim is to explore noninvasive deformation in the knee cartilage during athlete's jumping on the force plate.An original image algorithms and software were developed as well as complex mathematical models using high-performance computational power of finite element modeling together with one-dimensional dynamics model.The initial results showed cartilage deformation in the knee and future research will be focused on the methodology and more precisely determination of the stress and strain distribution in the knee cartilage during training phase of sportsman. PMID:24149600

  18. Long-lived reactive species formed on proteins induce changes in protein and lipid turnover.

    Science.gov (United States)

    Davies, Michael

    2014-10-01

    Proteins are major targets for oxidative damage in vivo due to their high abundance and rapid rates of reaction with both one-electron (radical) and two-electron oxidants (e.g. singlet oxygen, hypochlorous acid, peroxynitrous acid, reactive aldehydes). The turnover of both native and modified proteins is critical for maintenance of cell homeostasis, with this occurring via multiple pathways including proteasomes (for cytosolic species), the Lon protease (in mitochondria), and the endo-lysosomal systems (both extra- and intra-cellular species). Evidence has been presented for both enhanced and diminished rates of catabolism of modified proteins, as well as altered turnover of native (unmodified) proteins as a result of damage to these systems, potentially as a result of the accumulation of damaged proteins. In recent studies we have shown that long-lived reactive species forms on proteins (hydroperoxides, chloramines and aldehydes) can modify the activity of proteasomal and lysosomal enzymes. Some of the above species are efficient inhibitors of the tryptic and chymotryptic activities of the 26S proteasome, as well as lysosomal cathepsin and acid lipase activities. These are key species in the turnover of both proteins and lipoproteins. The loss of enzyme activity is accompanied in many cases, by oxidation of critical thiol residues via molecular reactions. For reactive aldehydes (either free or protein-bound) direct enzyme inhibition can occur as well as modulation of protein levels and, in the case of lysosomes, changes in lysosomal numbers. Overall, these data indicate that the formation of reactive species on proteins can modulate cell function by multiple pathways including interference with the turnover of native proteins (including critical cell signalling molecules) and alterations in the rate of clearance of modified proteins. Both pathways may contribute to the development of a number of human pathologies associated with oxidative damage. PMID:26461411

  19. Evaluation of influence of proteoglycans on hydration of articular cartilage with the use of ultrasound

    Directory of Open Access Journals (Sweden)

    Yi-yi YANG

    2015-04-01

    Full Text Available Objective To monitor the changes in hydration behaviour of articular cartilage induced by degradation of proteoglycans, and to explore the effect of proteoglycans on hydration behaviour of articular cartilage by using high-frequency ultrasound. Methods Twelve porcine patellae with smooth cartilage surface were prepared and equally divided into two groups: normal group without any enzyme treatment, and trypsin group they were treated with 0.25% trypsin for 8h to digest proteoglycan in the cartilage. The hydration behaviour of the cartilage tissue was scanned by high-frequency ultrasound system with a central frequency of 25MHz. Parameters including cartilage hydration strain and cartilage thickness were measured. The histopathological changes in the articular cartilage were observed under a light microscope. Results It took approximately 20min to reach equilibrium during the hydration process in the normal cartilages, while proteoglycan-degraded cartilage took only about 5min to achieve equilibrium. The equilibrium strain of normal cartilage was 3.5%±0.5%. The degradation of proteoglycans induced a significant decrease in equilibrium strain (1.8%±0.2%, P0.05. Conclusion Proteoglycans play an important role in hydration behaviour of articular cartilage. The degradation of proteoglycans could induce degeneration of cartilage structure and decrease in hydration behaviour after dehydration. DOI: 10.11855/j.issn.0577-7402.2015.03.03

  20. Preliminary investigation of intrinsic UV fluorescence spectroscopic changes associated with proteolytic digestion of bovine articular cartilage

    Science.gov (United States)

    Lewis, William; Padilla-Martinez, Juan-Pablo; Ortega-Martinez, Antonio; Franco, Walfre

    2016-03-01

    Degradation and destruction of articular cartilage is the etiology of osteoarthritis (OA), an entity second only to cardiovascular disease as a cause of disability in the United States. Joint mechanics and cartilage biochemistry are believed to play a role in OA; an optical tool to detect structural and chemical changes in articular cartilage might offer benefit for its early detection and treatment. The objective of the present study was to identify the spectral changes in intrinsic ultraviolet (UV) fluorescence of cartilage that occur after proteolytic digestion of cartilage. Bovine articular cartilage samples were incubated in varying concentrations of collagenase ranging from 10ug/mL up to 5mg/mL for 18 hours at 37°C, a model of OA. Pre- and post-incubation measurements were taken of the UV excitation-emission spectrum of each cartilage sample. Mechanical tests were performed to determine the pre- and post-digestion force/displacement ratio associated with indentation of each sample. Spectral changes in intrinsic cartilage fluorescence and stiffness of the cartilage were associated with proteolytic digestion. In particular, changes in the relative intensity of fluorescence peaks associated with pentosidine crosslinks (330 nm excitation, 390 nm emission) and tryptophan (290 nm excitation, 340 nm emission) were found to correlate with different degrees of cartilage digestion and cartilage stiffness. In principle, it may be possible to use UV fluorescence spectral data for early detection of damage to articular cartilage, and as a surrogate measure for cartilage stiffness.

  1. An overview of multiphase cartilage mechanical modelling and its role in understanding function and pathology.

    Science.gov (United States)

    Klika, Václav; Gaffney, Eamonn A; Chen, Ying-Chun; Brown, Cameron P

    2016-09-01

    There is a long history of mathematical and computational modelling with the objective of understanding the mechanisms governing cartilage׳s remarkable mechanical performance. Nonetheless, despite sophisticated modelling development, simulations of cartilage have consistently lagged behind structural knowledge and thus the relationship between structure and function in cartilage is not fully understood. However, in the most recent generation of studies, there is an emerging confluence between our structural knowledge and the structure represented in cartilage modelling. This raises the prospect of further refinement in our understanding of cartilage function and also the initiation of an engineering-level understanding for how structural degradation and ageing relates to cartilage dysfunction and pathology, as well as informing the potential design of prospective interventions. Aimed at researchers entering the field of cartilage modelling, we thus review the basic principles of cartilage models, discussing the underlying physics and assumptions in relatively simple settings, whilst presenting the derivation of relatively parsimonious multiphase cartilage models consistent with our discussions. We proceed to consider modern developments that start aligning the structure captured in the models with observed complexities. This emphasises the challenges associated with constitutive relations, boundary conditions, parameter estimation and validation in cartilage modelling programmes. Consequently, we further detail how both experimental interrogations and modelling developments can be utilised to investigate and reduce such difficulties before summarising how cartilage modelling initiatives may improve our understanding of cartilage ageing, pathology and intervention. PMID:27195911

  2. Chondroitin sulphate and heparan sulphate sulphation motifs and their proteoglycans are involved in articular cartilage formation during human foetal knee joint development.

    Science.gov (United States)

    Melrose, James; Isaacs, Marc D; Smith, Susan M; Hughes, Clare E; Little, Christopher B; Caterson, Bruce; Hayes, Anthony J

    2012-09-01

    Novel sulphation motifs within the glycosaminoglycan chain structure of chondroitin sulphate (CS) containing proteoglycans (PGs) are associated with sites of growth, differentiation and repair in many biological systems and there is compelling evidence that they function as molecular recognition sites that are involved in the binding, sequestration or presentation of soluble signalling molecules (e.g. morphogens, growth factors and cytokines). Here, using monoclonal antibodies 3B3(-), 4C3 and 7D4, we examine the distribution of native CS sulphation motifs within the developing connective tissues of the human foetal knee joint, both during and after joint cavitation. We show that the CS motifs have broad, overlapping distributions within the differentiating connective tissues before the joint has fully cavitated; however, after cavitation, they all localise very specifically to the presumptive articular cartilage tissue. Comparisons with the labelling patterns of heparan sulphate (HS), HS-PGs (perlecan, syndecan-4 and glypican-6) and FGF-2, molecules with known signalling roles in development, indicate that these also become localised to the future articular cartilage tissue after joint cavitation. Furthermore, they display interesting, overlapping distributions with the CS motifs, reflective of early tissue zonation. The overlapping expression patterns of these molecules at this site suggests they are involved, or co-participate, in early morphogenetic events underlying articular cartilage formation; thus having potential clinical relevance to mechanisms involved in its repair/regeneration. We propose that these CS sulphation motifs are involved in modulating the signalling gradients responsible for the cellular behaviours (proliferation, differentiation, matrix turnover) that shape the zonal tissue architecture present in mature articular cartilage. PMID:22617995

  3. Labour Turnover in the Hospitality Industry

    OpenAIRE

    Ersan Suria Pranoto

    2011-01-01

    Labour turnover are inevitable and many businesses and industries are dealing with this issue every single day. It is also a great issue in the Hospitality Industry, the intensity were varies according to the size of the establishment, some are low and many is as high as the height of their buildings. The fact also stated that workers in the hospitality industry in the early stage of their career expect to move from one job to another, creating a very low desirability of steady workplaces and...

  4. Assessment of the 18-month permanence of onlay tip cartilage grafts following rhinoplasty.

    Science.gov (United States)

    Persichetti, Paolo; Simone, Pierfranco; Carusi, Carlo

    2013-09-01

    Augmentation rhinoplasty requires addition of materials of various natures to reshape the nasal pyramid. Onlay tip grafts are single or multilayered grafts placed horizontally over the alar domes. The aim of the present study was to assess the 18-month permanence of onlay septal cartilage grafts. Twenty-eight patients underwent rhinoplasty with onlay tip cartilage graft, between June 2008 and November 2008 at the Campus Bio-Medico University in Rome, Italy. They were reviewed and photographed 6 months and 18 months postoperatively. Comparison of 6-month and 18-month postoperative pictures was performed with Adobe Photoshop CS. Measurements on pictures were taken with AutoCAD. Comparison of photographs showed no visible difference in nasal tip projection. Comparison of the measurements of tip projection showed a mean reduction of 0.06 mm (0.19%). Considerable stability of nasal tip projection after rhinoplasty with onlay tip grafts was observed postoperatively. Comparison of standardised digital photographs is a valid procedure to assess contour alterations of various anatomical structures after plastic surgery. PMID:23547534

  5. The Impact of Human Resource Management Practices on Employee Turnover

    OpenAIRE

    Ozoliņa-Ozola, I

    2014-01-01

    The aim of this research was to identify the human resource management practices that are effective for employee turnover reducing. For this purpose the methods of document analysis and expert survey were used. On the basis of analysis of the scientific literature retrieved from academic databases the human resource management practices, which were mentioned in connection with employee turnover, were detected and described its effect on employee turnover. By conducting two separate expert sur...

  6. Estimation of Employee Turnover with Competing Risks Models

    OpenAIRE

    Grzenda Wioletta; Buczyński Michał K.

    2015-01-01

    Employee turnover accompanies every business organization, regardless of the industry and size. Nowadays, many companies struggle with problems related to the lack of sufficient information about the nature of employee turnover processes. Therefore, comprehensive analysis of these processes is necessary. This article aims to examine the turnover of employees from a big manufacturing company using competing risks models with covariates and without covariates. This technique allows to incorpora...

  7. Factors of Personality leading to employee turnover in organisation

    OpenAIRE

    Lucie Vnoučková

    2013-01-01

    Employee turnover is quite costly. Firstly in terms of finance, secondly there is the possibility to lose knowledge workers and thirdly it may threaten knowledge continuity. Therefore, it is necessary to take care about causes leading to employee turnover. The aim of the paper is, based on the outcomes of primary survey, to identify and describe the specific causes leading to employee turnover and by naming them to suggest changes in human resource management leading to restriction or to comp...

  8. CEO Turnover: More Evidence on the Role of Performance Expectations

    OpenAIRE

    Humphreys, Brad; Paul, Rodney; Weinbach, Andrew

    2011-01-01

    Previous research on CEO turnover indicates that a number of factors, including age, firm performance, and expected firm performance affect CEO turnover. Measurement of expected performance in these studies is typically based on investment analysts’ forecasts of earnings; these expectations potentially suffer from a number of problems, including the tendency for CEOs to “manage” analysts’ expectations. We examine the relationship between performance expectations and CEO turnover using data fr...

  9. General practitioner turnover and migration in England 1990-94.

    OpenAIRE

    Taylor, D H; Leese, B

    1998-01-01

    BACKGROUND: In tandem with fears about a GP workforce crisis, increasing attention is being focused on the supply and distribution of primary care services: on general practitioners in particular. Differential turnover and migration across health authority boundaries could lead to a maldistribution of GPs, yet comprehensive studies of GP turnover are non-existent. AIM: To quantify general practitioner (GP) turnover and migration in England from 1990 to 1994. METHOD: Yearly data from 1 October...

  10. Peranan Bullying di Tempat Kerja Terhadap Intensi Turnover Pada Karyawan

    OpenAIRE

    Tarigan, Santri Permana

    2015-01-01

    Bullying behavior is repeated behavior that is performed by a person or group of persons to another person or another group which aims to humiliate, offensive, and intimidate. One of the effects of bullying behavior is turnover intention. This study aims to know the role of workplace bullying toward employees turnover intention. This study involved 67 employees were selected through purposive sampling technique. Measuring tool used turnover intention scale and workplace bullyin...

  11. Turnover of Senior Managers in Russian Privatised Firms

    OpenAIRE

    Alexander Muravyev

    2003-01-01

    This paper studies determinants of CEO turnover in Russian privatised enterprises using data from a recent survey of 437 firms. Its main finding is an inverse relationship between past performance of firms (measured by labour productivity) and the probability of their CEO replacement. The paper also shows that insider ownership inhibits CEO turnover, while both state and private outside ownership are associated with higher turnover rates. Moreover, the greater the share of regional government...

  12. Plant Turnover and Productivity Growth in Canadian Manufacturing

    OpenAIRE

    Gu, Wulong; Baldwin, John R.

    2003-01-01

    This paper outlines the size of the turnover in plants that have entered and exited the Canadian manufacturing sector during the three periods: 1973-1979, 1979-1988 and 1988-1997. It also examines the contribution of plant turnover to labour productivity growth in the manufacturing sector over the three periods. Plant turnover makes a significant contribution to productivity growth as more productive entrants replace exiting plants that are less productive. A disproportionately large fraction...

  13. A Hicksian model of labour turnover and local wage determination

    OpenAIRE

    Clark, G. L.

    1981-01-01

    Employers have a variety of reasons for attempting to stabilize turnover in their labour force. For example, specific skill requirements, the added costs of training inherent in hiring new workers, and the absolute demand for labour may stimulate firms to minimize labour turnover. One way of reducing turnover is for the individual firm to raise its wage rates. However, depending upon the relative tightness of the local labour market (reflected in the rates of hiring and unemployment), this co...

  14. Staff Turnover as a Possible Threat to Knowledge Loss

    OpenAIRE

    Linhartová Lucie; Urbancová Hana

    2011-01-01

    The article focuses on labour turnover as a potential threat to knowledge loss. Labour turnover results in an organizations inability to ensure knowledge continuity. In this study, induction was used to identify factors within organizations that determine employees’ exit from organizations. The verifiability of these factors was tested by means of correlation and regression. Subsequently, the presented causes of employee turnover were specified as potential threat to knowledge loss. In the cu...

  15. Cohort Turnover and Productivity: The July Phenomenon in Teaching Hospitals

    OpenAIRE

    Robert S. Huckman; Jason Barro

    2005-01-01

    The impact of labor turnover on productivity has received a great deal of attention in the literature on organizations. We consider the impact of cohort turnover -- the simultaneous exit of a large number of experienced employees and a similarly sized entry of new workers -- on productivity in the context of teaching hospitals. In particular, we examine the impact of the annual July turnover of house staff (i.e., residents and fellows) in American teaching hospitals on levels of resource util...

  16. Does Total Rewards Reduce the Core Employees’ Turnover Intention?

    OpenAIRE

    Zhoutao Cao; Jinxi Chen; Yixiao Song

    2013-01-01

    The turnover of core employees is great lost for industrial companies, so that the research of turnover Intention(TI) is critical to enterprise. Recently, the researches discuss the factors that affect turnover invention fromdifferent views. Based on the concept of total rewards (TR) we go deep into the influencing factors. In this paper,we used ULR and hierarchical regression analysis to build model with organizational justice (OJ) as moderatorvariable. Results showed that the five elements ...

  17. Psychosocial predictors of actual turnover among Belgian health care workers

    OpenAIRE

    Derycke, Hanne; Vlerick, Peter; Clays, Els; D'hoore, William; Braeckman, Lutgart

    2010-01-01

    Background: Turnover of nursing staff is a major challenge for healthcare settings and for healthcare in general, urging the need to improve retention. Aim: The aim was to explore the prospective relations between personal and psychosocial work-related factors and actual turnover among Belgian healthcare workers. Methods: Predictors of actual turnover were assessed using the longitudinal Belgian data from the Nurses Early Exit Study (NEXT). Two self-administered questionnaires with a time...

  18. The pro-inflammatory cytokine 14-3-3ε is a ligand of CD13 in cartilage.

    Science.gov (United States)

    Nefla, Meriam; Sudre, Laure; Denat, Guillaume; Priam, Sabrina; Andre-Leroux, Gwenaëlle; Berenbaum, Francis; Jacques, Claire

    2015-09-01

    Osteoarthritis is a whole-joint disease characterized by the progressive destruction of articular cartilage involving abnormal communication between subchondral bone and cartilage. Our team previously identified 14-3-3ε protein as a subchondral bone soluble mediator altering cartilage homeostasis. The aim of this study was to investigate the involvement of CD13 (also known as aminopeptidase N, APN) in the chondrocyte response to 14-3-3ε. After identifying CD13 in chondrocytes, we knocked down CD13 with small interfering RNA (siRNA) and blocking antibodies in articular chondrocytes. 14-3-3ε-induced MMP-3 and MMP-13 was significantly reduced with CD13 knockdown, which suggests that it has a crucial role in 14-3-3ε signal transduction. Aminopeptidase N activity was identified in chondrocytes, but the activity was unchanged after stimulation with 14-3-3ε. Direct interaction between CD13 and 14-3-3ε was then demonstrated by surface plasmon resonance. Using labeled 14-3-3ε, we also found that 14-3-3ε binds to the surface of chondrocytes in a manner that is dependent on CD13. Taken together, these results suggest that 14-3-3ε might directly bind to CD13, which transmits its signal in chondrocytes to induce a catabolic phenotype similar to that observed in osteoarthritis. The 14-3-3ε-CD13 interaction could be a new therapeutic target in osteoarthritis. PMID:26208633

  19. The pro-inflammatory cytokine 14-3-3ε is a ligand of CD13 in cartilage

    Science.gov (United States)

    Nefla, Meriam; Sudre, Laure; Denat, Guillaume; Priam, Sabrina; Andre-Leroux, Gwenaëlle; Berenbaum, Francis; Jacques, Claire

    2015-01-01

    ABSTRACT Osteoarthritis is a whole-joint disease characterized by the progressive destruction of articular cartilage involving abnormal communication between subchondral bone and cartilage. Our team previously identified 14-3-3ε protein as a subchondral bone soluble mediator altering cartilage homeostasis. The aim of this study was to investigate the involvement of CD13 (also known as aminopeptidase N, APN) in the chondrocyte response to 14-3-3ε. After identifying CD13 in chondrocytes, we knocked down CD13 with small interfering RNA (siRNA) and blocking antibodies in articular chondrocytes. 14-3-3ε-induced MMP-3 and MMP-13 was significantly reduced with CD13 knockdown, which suggests that it has a crucial role in 14-3-3ε signal transduction. Aminopeptidase N activity was identified in chondrocytes, but the activity was unchanged after stimulation with 14-3-3ε. Direct interaction between CD13 and 14-3-3ε was then demonstrated by surface plasmon resonance. Using labeled 14-3-3ε, we also found that 14-3-3ε binds to the surface of chondrocytes in a manner that is dependent on CD13. Taken together, these results suggest that 14-3-3ε might directly bind to CD13, which transmits its signal in chondrocytes to induce a catabolic phenotype similar to that observed in osteoarthritis. The 14-3-3ε–CD13 interaction could be a new therapeutic target in osteoarthritis. PMID:26208633

  20. Matrilin-3 Role in Cartilage Development and Osteoarthritis.

    Science.gov (United States)

    Muttigi, Manjunatha S; Han, Inbo; Park, Hun-Kuk; Park, Hansoo; Lee, Soo-Hong

    2016-01-01

    The extracellular matrix (ECM) of cartilage performs essential functions in differentiation and chondroprogenitor cell maintenance during development and regeneration. Here, we discuss the vital role of matrilin-3, an ECM protein involved in cartilage development and potential osteoarthritis pathomechanisms. As an adaptor protein, matrilin-3 binds to collagen IX to form a filamentous network around cells. Matrilin-3 is an essential component during cartilage development and ossification. In addition, it interacts directly or indirectly with transforming growth factor β (TGF-β), and bone morphogenetic protein 2 (BMP2) eventually regulates chondrocyte proliferation and hypertrophic differentiation. Interestingly, matrilin-3 increases interleukin receptor antagonists (IL-Ra) in chondrocytes, suggesting its role in the suppression of IL-1β-mediated inflammatory action. Matrilin-3 downregulates the expression of matrix-degrading enzymes, such as a disintegrin metalloproteinase with thrombospondin motifs 4 (ADAMTS4) and ADAMTS5, matrix metalloproteinase 13 (MMP13), and collagen X, a hypertrophy marker during development and inflammatory conditions. Matrilin-3 essentially enhances collagen II and aggrecan expression, which are required to maintain the tensile strength and elasticity of cartilage, respectively. Interestingly, despite these attributes, matrilin-3 induces osteoarthritis-associated markers in chondrocytes in a concentration-dependent manner. Existing data provide insights into the critical role of matrilin-3 in inflammation, matrix degradation, and matrix formation in cartilage development and osteoarthritis. PMID:27104523

  1. The evolution of articular cartilage imaging and its impact on clinical practice

    International Nuclear Information System (INIS)

    Over the past four decades, articular cartilage imaging has developed rapidly. Imaging now plays a critical role not only in clinical practice and therapeutic decisions but also in the basic research probing our understanding of cartilage physiology and biomechanics. (orig.)

  2. Cartilage Tissue Engineering: the effect of different biomaterials, cell types and culture methods

    NARCIS (Netherlands)

    W.J.C.M. Marijnissen (Willem)

    2006-01-01

    textabstractChapter 1 outlines the normal structure and composition of articular cartilage and the inefficient spontaneous healing response after focal damage. Current surgical treatment options are briefly discussed and tissue engineering techniques for the repair of articular cartilage defects

  3. Cartilage Grown in Lab Might One Day Help Younger Arthritis Sufferers

    Science.gov (United States)

    ... Cartilage Grown in Lab Might One Day Help Younger Arthritis Sufferers Made of patients' stem cells and ... eliminate the need for hip replacement surgery in younger arthritis patients. The cartilage hasn't been tested ...

  4. Turnover of dhurrin in green sorghum seedlings

    International Nuclear Information System (INIS)

    The turnover of dhurrin in green seedlings of Sorghum bicolor (Linn) Moench var Redland x Greenleaf, Sudan 70 has been investigated using glyphosate and pulse-labeling studies with 14C-tyrosine and [14C]shikimic acid. The rate of dhurrin breakdown was 4.8 nanomoles per hour in the shoot and 1.4 nanomoles per hour in the root. The rate of dhurrin accumulation in the shoot of 4- to 5-day-old seedlings was high but decreased with age until at the peak period of dhurrin accumulation, the rates of dhurrin synthesis and breakdown were equal. Using a first order equation (an approximation) the rate of dhurrin synthesis (which equals accumulation plus breakdown rates) was 17.4 nanomoles per hour in the shoot and 4.1 nanomoles per hour in the root. In both tissues, the breakdown rate was between 27 and 34% of their synthetic capacity within the experimental period. Dhurrin synthesis in green sorghum seedlings occurred in both the light and dark photoperiods but was faster in the dark period. The result is discussed in relation to the possible metabolic roles of the turnover

  5. Baseline ambulatory knee kinematics are associated with changes in cartilage thickness in osteoarthritic patients over 5 years.

    Science.gov (United States)

    Favre, Julien; Erhart-Hledik, Jennifer C; Chehab, Eric F; Andriacchi, Thomas P

    2016-06-14

    Although kinematic alterations during walking have been reported with knee osteoarthritis (OA), there is a paucity of longitudinal data, therefore limiting our understanding of the role of kinematics in OA development. This study tested the hypothesis that less knee extension angle and less posterior displacement of the femur relative to the tibia during the heel-strike portion of the gait cycle are associated with greater loss of medial cartilage thickness during a follow-up period of five years. This study also tested for associations between flexion-extension angle and anterior-posterior displacement during other periods of the gait cycle and 5-year cartilage thinning. 16 subjects with moderate medial knee OA were tested with gait analysis and MRI at baseline and had a follow-up MRI after 5 years. Linear regressions were used to assess the relationship between changes in cartilage thickness and baseline kinematics using Pearson correlation coefficients. Multivariate regressions were also performed to adjust for gender, baseline age, BMI, walking speed, Kellgren/Lawrence grade, and baseline knee pain score. As hypothesized, baseline knee flexion angle and femoral displacement during heel-strike and other gait cycle periods were significantly associated with medial femoral and tibial cartilage thinning at the 5 year follow-up; these associations were strengthened after adjustment for covariates. This study provided new insight into the pathogenesis of knee OA where baseline knee kinematics were associated with longitudinal disease progression. These results could serve as a basis for developing newer gait modification interventions to reduce the risk for developing knee OA. PMID:27178021

  6. Variations in radiographic appearance of articular cartilage of knee joints in persons of 35 to 65 years of age

    Directory of Open Access Journals (Sweden)

    Himani Pulivarthi

    2015-01-01

    Full Text Available Background: Osteoarthritis is a slowly progressive degenerative disease characterized by gradual loss of articular cartilage. Osteoarthritis is not a normal process of ageing processes. Age related changes are distinct from osteoarthritic changes but when coupled with certain precipitating factors like obesity, muscle weakness and neurological dysfunction may play an important role in the causation of osteoarthritis. Osteoarthritis occurrence appears to increase with patient's age in a non-linear fashion. The prevalence of disease increases dramatically after the age of 50 years, likely because of age related alterations in collagen and proteoglycan synthesis coupled with diminished nutrient supply to the cartilage. Methods: In this paper presenting the naked eye assessment of radiographic appearance of articular cartilage of knee joints of 100 persons (both men and women of 35 to 65 years of age with symptoms like pain and stiffness of the joint. Results: Parameters like changes in the joint space width, the presence or absence of osteophytes and subchondral sclerosis and cysts were noted. The correlation between the patient's age, sex, symptoms and radiological appearance were observed. Conclusion: Osteoarthritis has a higher prevalence and more often generalized in women than in men. Before the age of 50 years, the incidence of osteoarthritis is low and men have a slightly higher prevalence than women, but after the age of 50 years, the disease becomes more frequent and women have a much higher prevalence with a female to male ration of about 12:1. The reason for this is sex difference in cartilage volume. [Int J Res Med Sci 2015; 3(1.000: 22-26

  7. Cold Atmospheric Plasma Modified Electrospun Scaffolds with Embedded Microspheres for Improved Cartilage Regeneration

    OpenAIRE

    Wei Zhu; Castro, Nathan J.; Xiaoqian Cheng; Michael Keidar; Lijie Grace Zhang

    2015-01-01

    Articular cartilage is prone to degeneration and possesses extremely poor self-healing capacity due to inherent low cell density and the absence of a vasculature network. Tissue engineered cartilage scaffolds show promise for cartilage repair. However, there still remains a lack of ideal biomimetic tissue scaffolds which effectively stimulate cartilage regeneration with appropriate functional properties. Therefore, the objective of this study is to develop a novel biomimetic and bioactive ele...

  8. Reconstruction of focal cartilage defects in the talus with miniarthrotomy and collagen matrix

    OpenAIRE

    Walther, M.; Altenberger, S; Kriegelstein, S; Volkering, C; Röser, A.

    2014-01-01

    Surgical principal and objective Treatment of focal cartilage defects (traumatic or osteochondrosis dissecans) of the talus using a collagen matrix. The goal is to stabilize the superclot formed after microfracturing to accommodate cartilage repair. The procedure can be carried out via miniarthrotomy, without medial malleolus osteotomy. Indications International Cartilage Repair Society (ICRS) grade III and IV focal cartilage defects of the talus > 1.5 cm2. Contraindications Generalized osteo...

  9. Viscoelastic properties of bovine knee joint articular cartilage: dependency on thickness and loading frequency

    OpenAIRE

    Espino, Daniel M; Shepherd, Duncan ET; Hukins, David WL

    2014-01-01

    Background The knee is an incongruent joint predisposed to developing osteoarthritis, with certain regions being more at risk of cartilage degeneration even in non-osteoarthrosed joints. At present it is unknown if knee regions prone to cartilage degeneration have similar storage and/or loss stiffness, and frequency-dependent trends, to other knee joint cartilage. The aim of this study was to determine the range of frequency-dependent, viscoelastic stiffness of articular cartilage across the ...

  10. Wnt/β-catenin signaling of cartilage canal and osteochondral junction chondrocytes and full thickness cartilage in early equine osteochondrosis.

    Science.gov (United States)

    Kinsley, Marc A; Semevolos, Stacy A; Duesterdieck-Zellmer, Katja F

    2015-10-01

    The objective of this study was to elucidate gene and protein expression of Wnt signaling molecules in chondrocytes of foals having early osteochondrosis (OC) versus normal controls. The hypothesis was that increased expression of components of Wnt signaling pathway in osteochondral junction (OCJ) and cartilage canal (CC) chondrocytes would be found in early OC when compared to controls. Paraffin-embedded osteochondral samples (7 OC, 8 normal) and cDNA from whole cartilage (7 OC, 10 normal) and chondrocytes surrounding cartilage canals and osteochondral junctions captured with laser capture microdissection (4 OC, 6 normal) were obtained from femoropatellar joints of 17 immature horses. Equine-specific Wnt signaling molecule mRNA expression levels were evaluated by two-step real-time qPCR. Spatial tissue protein expression of β-catenin, Wnt-11, Wnt-4, and Dkk-1 was determined by immunohistochemistry. There was significantly decreased Wnt-11 and increased β-catenin, Wnt-5b, Dkk-1, Lrp6, Wif-1, Axin1, and SC-PEP gene expression in early OC cartilage canal chondrocytes compared to controls. There was also significantly increased β-catenin gene expression in early OC osteochondral junction chondrocytes compared to controls. Based on this study, abundant gene expression differences in OC chondrocytes surrounding cartilage canals suggest pathways associated with catabolism and inhibition of chondrocyte maturation are targeted in early OC pathogenesis. PMID:25676127

  11. Does Radio Frequency Ablation (RFA) Epiphysiodesis Affect Joint Cartilage?

    DEFF Research Database (Denmark)

    Shiguetomi Medina, Juan Manuel; Abood, Ahmed Abdul-Hussein; Rahbek, Ole;

    Background: Epiphysiodesis made with RFA has resulted, in animal models, an effective procedure that disrupts the growth plate and induces LLD. This procedure involves an increase of temperature (>92°C) of the targeted region causing thermal damage. To our knowledge, no study that investigates...... the effect of this procedure in the adjacent joint articular cartilage has been reported Purpose / Aim of Study: Proof of concept that epiphysiodesis made with RFA is a safe procedure that disrupts the growth plate without damaging the adjacent joint articular cartilage Materials and Methods: RFA...... Epiphysiodesis RFA was done for 8 minutes in vivo in 40 growing pig tibia physis. In addition, three tibiae were ablated for 16 minutes, and three more for 24 minutes. As a damage reference, 6 tibiae were ablated on the joint articular cartilage for 8 minutes. MRI was done ex vivo after the procedure to evaluate...

  12. Evaluation of Automated Volumetric Cartilage Quantification for Hip Preservation Surgery.

    Science.gov (United States)

    Ramme, Austin J; Guss, Michael S; Vira, Shaleen; Vigdorchik, Jonathan M; Newe, Axel; Raithel, Esther; Chang, Gregory

    2016-01-01

    Automating the process of femoroacetabular cartilage identification from magnetic resonance imaging (MRI) images has important implications to guiding clinical care by providing a temporal metric that allows for optimizing the timing for joint preservation surgery. In this paper, we evaluate a new automated cartilage segmentation method using a time trial, segmented volume comparison, overlap metrics, and Euclidean distance mapping. We report interrater overlap metrics using the true fast imaging with steady-state precession MRI sequence of 0.874, 0.546, and 0.704 for the total overlap, union overlap, and mean overlap, respectively. This method was 3.28× faster than manual segmentation. This technique provides clinicians with volumetric cartilage information that is useful for optimizing the timing for joint preservation procedures. PMID:26377376

  13. Cartilage oligomeric matrix protein enhances the vascularization of acellular nerves

    Directory of Open Access Journals (Sweden)

    Wei-ling Cui

    2016-01-01

    Full Text Available Vascularization of acellular nerves has been shown to contribute to nerve bridging. In this study, we used a 10-mm sciatic nerve defect model in rats to determine whether cartilage oligomeric matrix protein enhances the vascularization of injured acellular nerves. The rat nerve defects were treated with acellular nerve grafting (control group alone or acellular nerve grafting combined with intraperitoneal injection of cartilage oligomeric matrix protein (experimental group. As shown through two-dimensional imaging, the vessels began to invade into the acellular nerve graft from both anastomotic ends at day 7 post-operation, and gradually covered the entire graft at day 21. The vascular density, vascular area, and the velocity of revascularization in the experimental group were all higher than those in the control group. These results indicate that cartilage oligomeric matrix protein enhances the vascularization of acellular nerves.

  14. Gene Transfer Strategies to Promote Chondrogenesis and Cartilage Regeneration.

    Science.gov (United States)

    Im, Gun-Il

    2016-04-01

    Gene transfer has been used experimentally to promote chondrogenesis and cartilage regeneration. While it is controversial to apply gene therapy for nonlethal conditions such as cartilage defect, there is a possibility that the transfer of therapeutic transgenes may dramatically increase the effectiveness of cell therapy and reduce the quantity of cells that are needed to regenerate cartilage. Single or combination of growth factors and transcription factors has been transferred to mesenchymal stem cells or articular chondrocytes using both nonviral and viral approaches. The current challenge for the clinical applications of genetically modified cells is ensuring the safety of gene therapy while guaranteeing effectiveness. Viral gene delivery methods have been mainstays currently with enhanced safety features being recently refined. On the other hand, efficiency has been greatly improved in nonviral delivery. This review summarizes the history and recent update on the gene transfer to enhance chondrogenesis from stem cells or articular chondrocytes. PMID:26414246

  15. Articular Cartilage Thickness Measured with US is Not as Easy as It Appears

    DEFF Research Database (Denmark)

    Torp-Pedersen, Søren; Bartels, E. M.; Wilhjelm, Jens E.;

    2011-01-01

    Background: Theoretically, the high spatial resolution of US makes it well suited to monitor the decrease in articular cartilage thickness in osteoarthritis. A requirement is, however, that the borders of the cartilage are correctly identified and that the cartilage ismeasured under orthogonal in...

  16. Articular cartilage thickness measured with US is not as easy as it appears

    DEFF Research Database (Denmark)

    Torp-Pedersen, S; Bartels, E M; Wilhjelm, Jens E.;

    2011-01-01

    Theoretically, the high spatial resolution of US makes it well suited to monitor the decrease in articular cartilage thickness in osteoarthritis. A requirement is, however, that the borders of the cartilage are correctly identified and that the cartilage is measured under orthogonal insonation. I...

  17. Ultrasonographic Measurement of the Femoral Cartilage Thickness in Hemiparetic Patients after Stroke

    Science.gov (United States)

    Tunc, Hakan; Oken, Oznur; Kara, Murat; Tiftik, Tulay; Dogu, Beril; Unlu, Zeliha; Ozcakar, Levent

    2012-01-01

    The aim of the study was to evaluate the femoral cartilage thicknesses of hemiparetic patients after stroke using musculoskeletal ultrasonography and to determine whether there is any correlation between cartilage thicknesses and the clinical characteristics of the patients. Femoral cartilage thicknesses of both knees were measured in 87 (33…

  18. Tibiofemoral cartilage contact biomechanics in patients after reconstruction of a ruptured anterior cruciate ligament.

    Science.gov (United States)

    Hosseini, Ali; Van de Velde, Samuel; Gill, Thomas J; Li, Guoan

    2012-11-01

    We investigated the in vivo cartilage contact biomechanics of the tibiofemoral joint in patients after reconstruction of a ruptured anterior cruciate ligament (ACL). A dual fluoroscopic and MR imaging technique was used to investigate the cartilage contact biomechanics of the tibiofemoral joint during in vivo weight-bearing flexion of the knee in eight patients 6 months following clinically successful reconstruction of an acute isolated ACL rupture. The location of tibiofemoral cartilage contact, size of the contact area, cartilage thickness at the contact area, and magnitude of the cartilage contact deformation of the ACL-reconstructed knees were compared with those previously measured in intact (contralateral) knees and ACL-deficient knees of the same subjects. Contact biomechanics of the tibiofemoral cartilage after ACL reconstruction were similar to those measured in intact knees. However, at lower flexion, the abnormal posterior and lateral shift of cartilage contact location to smaller regions of thinner tibial cartilage that has been described in ACL-deficient knees persisted in ACL-reconstructed knees, resulting in an increase of the magnitude of cartilage contact deformation at those flexion angles. Reconstruction of the ACL restored some of the in vivo cartilage contact biomechanics of the tibiofemoral joint to normal. Clinically, recovering anterior knee stability might be insufficient to prevent post-operative cartilage degeneration due to lack of restoration of in vivo cartilage contact biomechanics. PMID:22528687

  19. Analysis of cartilage-polydioxanone foil composite grafts.

    Science.gov (United States)

    Kim, James H; Wong, Brian

    2013-12-01

    This study presents an analytical investigation into the mechanical behavior of a cartilage-polydioxanone (PDS) plate composite grafts. Numerical methods are used to provide a first-order, numerical model of the flexural stiffness of a cartilage-PDS graft. Flexural stiffness is a measure of resistance to bending and is inversely related to the amount of deformation a structure may experience when subjected to bending forces. The cartilage-PDS graft was modeled as a single composite beam. Using Bernoulli-Euler beam theory, a closed form equation for the theoretical flexural stiffness of the composite graft was developed. A parametric analysis was performed to see how the flexural properties of the composite model changed with varying thicknesses of PDS foil. The stiffness of the cartilage-PDS composite using 0.15-mm-thick PDS was four times higher than cartilage alone. The composite with a 0.5-mm-thick PDS graft was only 1.7 times stiffer than the composite with the 0.15-mm-thick PDS graft. Although a thicker graft material will yield higher flexural stiffness for the composite, the relationship between composite stiffness and PDS thickness is nonlinear. After a critical point, increments in graft thickness produce gradually smaller improvements in flexural stiffness. The small increase in stiffness when using the thicker PDS foils versus the 0.15 mm PDS foil may not be worth the potential complications (prolonged foreign body reaction, reduction in nutrient diffusion to cartilage) of using thicker artificial grafts. PMID:24327249

  20. Magnetic resonance imaging of hip joint cartilage and labrum

    Directory of Open Access Journals (Sweden)

    Christoph Zilkens

    2011-09-01

    Full Text Available Hip joint instability and impingement are the most common biomechanical risk factors that put the hip joint at risk to develop premature osteoarthritis. Several surgical procedures like periacetabular osteotomy for hip dysplasia or hip arthroscopy or safe surgical hip dislocation for femoroacetabular impingement aim at restoring the hip anatomy. However, the success of joint preserving surgical procedures is limited by the amount of pre-existing cartilage damage. Biochemically sensitive MRI techniques like delayed Gadolinium Enhanced MRI of Cartilage (dGEMRIC might help to monitor the effect of surgical or non-surgical procedures in the effort to halt or even reverse joint damage.

  1. How Multiple Interventions Influenced Employee Turnover: A Case Study.

    Science.gov (United States)

    Hatcher, Timothy

    1999-01-01

    A 3-year study of 46 textile industry workers identified causes of employee turnover (supervision, training, organizational communication) using performance analysis. A study of multiple interventions based on the analysis resulted in changes in orientation procedures, organizational leadership, and climate, reducing turnover by 24%. (SK)

  2. Voluntary Turnover and Women Administrators in Higher Education

    Science.gov (United States)

    Jo, Victoria H.

    2008-01-01

    A salient characteristic about the U.S. workforce is the continual process of voluntary employee turnover, which can be problematic for employers who invest a substantial amount of time and money in recruiting and training employees. This paper discusses the effects of workplace policies and practices on the voluntary turnover of women…

  3. Estimating Cause: Teacher Turnover and School Effectiveness in Michigan

    Science.gov (United States)

    Keesler, Venessa; Schneider, Barbara

    2010-01-01

    The purpose of this paper is investigate issues related to within-school teacher supply and school-specific teacher turnover within the state of Michigan using state administrative data on Michigan's teaching force. This paper 1) investigates the key predictors of teacher turnover and mobility, 2) develops a profile of schools that are likely to…

  4. Understanding the Impacts of Induction Programs on Beginning Teacher Turnover

    Science.gov (United States)

    Kang, Seok

    2010-01-01

    This study examines impacts of mentoring and induction activities on beginning teacher turnover using the School and Staffing Survey (SASS) of 1999-2000 and the Teacher Follow-up Survey (TFS) of 2000-2001. In order to improve understanding of the influence of induction programs on beginning teacher turnover, three models are developed to achieve…

  5. Re-Examining the Relationship between Age and Voluntary Turnover

    Science.gov (United States)

    Ng, Thomas W. H.; Feldman, Daniel C.

    2009-01-01

    In their quantitative review of the literature, Healy, Lehman, and McDaniel [Healy, M. C., Lehman, M., & McDaniel, M. A. (1995). Age and voluntary turnover: A quantitative review. "Personnel Psychology, 48", 335-345] concluded that age is only weakly related to voluntary turnover (average r = -0.08). However, with the significant changes in…

  6. The Link between Training Satisfaction, Work Engagement and Turnover Intention

    Science.gov (United States)

    Memon, Mumtaz Ali; Salleh, Rohani; Baharom, Mohamed Noor Rosli

    2016-01-01

    Purpose: The purpose of this paper is to examine the casual relationship between training satisfaction, work engagement (WE) and turnover intention and the mediating role of WE between training satisfaction and turnover intention. Design/methodology/approach: Data were collected from 409 oil and gas professionals using an email survey…

  7. Estimating average cellular turnover from BrdU measurements

    NARCIS (Netherlands)

    Boer, R.J. de; Mohri, H.; Ho, D.D.; Perelson, A.S.

    2003-01-01

    Cellular turnover rates in the immune system can be determined by labelling dividing cells with 5-bromo- 29-deoxyuridine (BrdU) or deuterated glucose ( ²H-glucose). To estimate the turnover rate from such measurements one has to fit a particular mathematical model to the data. The biological assum

  8. Predicting Turnover: Validating the Intent to Leave Child Welfare Scale

    Science.gov (United States)

    Auerbach, Charles; Schudrich, Wendy Zeitlin; Lawrence, Catherine K.; Claiborne, Nancy; McGowan, Brenda G.

    2014-01-01

    A number of proxies have been used in child welfare workforce research to represent actual turnover; however, there have been no psychometric studies to validate a scale specifically designed for this purpose. The Intent to Leave Child Welfare Scale is a proxy for actual turnover that measures workers' intention to leave. This scale was…

  9. PERAN STRES KERJA DAN KEPUASAN KERJA UNTUK MENGURANGI TURNOVER INTENTION

    OpenAIRE

    Syarifah Nazenin; Palupiningdyah Palupiningdyah

    2014-01-01

    Tujuan penelitian ini untuk menguji pengaruh variabel stres kerja dan kepuasan kerja pada turnover intention karyawan tetap bagian produksi. Sampel penelitian ini adalah 86 responden, menggunakan metode Slovin dengan teknik probability sampling dengan jenis proportionate random sampling. Berdasarkan hasil penelitian, menunjukkan bahwa stres kerja berpengaruh positif signifikan pada turnover intention. Kemudian, kepuasan kerja berpengaruh negatif signifikan. Penelitian ini menyimpulkan, bahwa ...

  10. Organisational commitment and turnover intentions in humanitarian organisations

    NARCIS (Netherlands)

    Wijnmaalen, Julia; Heyse, Liesbet; Voordijk, Hans

    2016-01-01

    Unwanted staff turnover is a prominent HRM problem in humanitarian organisations. In the profit sector, HRM tools such as pay, benefits, socialisation and training have proven to be effective in increasing organisational commitment and decreasing staff turnover. This study explores whether such tool

  11. Investigating Occupational Commitment and Turnover Intention Relationship with Burnout Syndrome

    OpenAIRE

    Aydem Ciftcioglu

    2011-01-01

    This study investigates burnout components impact on accountant’s occupational commitment and occupational turnover intention interaction. The data used in this study was taken from randomly selected 162 accountants who are the members of Istanbul Chambers of Certified Public Accountants (ICCPA). The results reveal that only emotional exhaustion component of burnout has partial mediating effect between affective occupational commitment and occupational turnover intention.

  12. A new mechanistic scenario for the origin and evolution of vertebrate cartilage.

    Directory of Open Access Journals (Sweden)

    Maria Cattell

    Full Text Available The appearance of cellular cartilage was a defining event in vertebrate evolution because it made possible the physical expansion of the vertebrate "new head". Despite its central role in vertebrate evolution, the origin of cellular cartilage has been difficult to understand. This is largely due to a lack of informative evolutionary intermediates linking vertebrate cellular cartilage to the acellular cartilage of invertebrate chordates. The basal jawless vertebrate, lamprey, has long been considered key to understanding the evolution of vertebrate cartilage. However, histological analyses of the lamprey head skeleton suggest it is composed of modern cellular cartilage and a putatively unrelated connective tissue called mucocartilage, with no obvious transitional tissue. Here we take a molecular approach to better understand the evolutionary relationships between lamprey cellular cartilage, gnathostome cellular cartilage, and lamprey mucocartilage. We find that despite overt histological similarity, lamprey and gnathostome cellular cartilage utilize divergent gene regulatory networks (GRNs. While the gnathostome cellular cartilage GRN broadly incorporates Runx, Barx, and Alx transcription factors, lamprey cellular cartilage does not express Runx or Barx, and only deploys Alx genes in certain regions. Furthermore, we find that lamprey mucocartilage, despite its distinctive mesenchymal morphology, deploys every component of the gnathostome cartilage GRN, albeit in different domains. Based on these findings, and previous work, we propose a stepwise model for the evolution of vertebrate cellular cartilage in which the appearance of a generic neural crest-derived skeletal tissue was followed by a phase of skeletal tissue diversification in early agnathans. In the gnathostome lineage, a single type of rigid cellular cartilage became dominant, replacing other skeletal tissues and evolving via gene cooption to become the definitive cellular cartilage of

  13. Bone mass and turnover in fibromyalgia

    DEFF Research Database (Denmark)

    Jacobsen, Søren; Gam, A; Egsmose, C;

    1993-01-01

    Physical inactivity accelerates bone loss. Since patients with fibromyalgia are relatively physically inactive, bone mass and markers of bone metabolism were determined in 12 premenopausal women with fibromyalgia and in healthy age matched female control subjects. No differences were found in...... lumbar bone mineral density, femoral neck bone mineral density, serum levels of alkaline phosphatase, osteocalcin, ionized calcium and phosphate. The urinary excretion of both hydroxyproline and calcium relative to urinary creatinine excretion was significantly higher in patients with fibromyalgia, p = 0.......01. This was linked to lower urinary creatinine excretion (p = 0.02) probably reflecting lower physical activity in the patients with fibromyalgia. We conclude that bone mass and turnover are generally not affected in premenopausal women with fibromyalgia....

  14. Osteoarthritic Cartilage is more Homogeneous than Healthy Cartilage – Identification of a Superior ROI Co-localised with a Major Risk Factor for Osteoarthritis

    DEFF Research Database (Denmark)

    Qazi, Arish Asif; Dam, Erik B.; Nielsen, Mads;

    2007-01-01

    Rationale and Objectives Cartilage loss as determined by magnetic resonance imaging (MRI) or joint space narrowing as determined by x-ray is the result of cartilage erosion. However, metabolic processes within the cartilage that later result in cartilage loss may be a more sensitive assessment...... those with OA. The purpose of this study was twofold. First, we wished to evaluate whether the results on cartilage homogeneity from the previous study can be reproduced using an independent population. Second, based on the homogeneity framework, we present an automatic technique that partitions the...... the region was evaluated by testing for overfitting. Three different regularization techniques were evaluated for reducing overfitting errors. Results The P values for separating the different groups based on cartilage homogeneity were 2 × 10-5 (KL 0 versus KL 1) and 1 × 10-7 (KL 0 versus KL >0...

  15. Pitfalls in quantifying species turnover: the residency effect

    Directory of Open Access Journals (Sweden)

    Kevin Chase Burns

    2014-03-01

    Full Text Available The composition of ecological communities changes continuously through time and space. Understanding this turnover in species composition is a central goal in biogeography, but quantifying species turnover can be problematic. Here, I describe an underappreciated source of bias in quantifying species turnover, namely ‘the residency effect’, which occurs when the contiguous distributions of species across sampling domains are small relative to census intervals. I present the results of a simulation model that illustrates the problem theoretically and then I demonstrate the problem empirically using a long-term dataset of plant species turnover on islands. Results from both exercises indicate that empirical estimates of species turnover may be susceptible to significant observer bias, which may potentially cloud a better understanding of how the composition of ecological communities changes through time.

  16. Turnover of fibrillar collagen in soft biological tissue with application to the expansion of abdominal aortic aneurysms

    OpenAIRE

    Martufi, G.; Gasser, T C

    2012-01-01

    A better understanding of the inherent properties of vascular tissue to adapt to its mechanical environment is crucial to improve the predictability of biomechanical simulations. Fibrillar collagen in the vascular wall plays a central role in tissue adaptation owing to its relatively short lifetime. Pathological alterations of collagen turnover may fail to result in homeostasis and could be responsible for abdominal aortic aneurysm (AAA) growth at later stages of the disease. For this reason ...

  17. Oncogenic pathways and myrna: effects on messenger's turnover, regulation by synthetic oligo ribonucleotides and therapeutic applications in experimental settings

    International Nuclear Information System (INIS)

    The project has been focusing on molecular mechanisms determining the rate of RNA degradation eventually important to regulate gene expression and phenotype at post transcription level. Exogenous synthetic oligonucleotides targeting the relevant domains of b- RNA degradation could stabilize the transcript, efficiently enhance gene expression and alter the cellular phenotype accordingly. The experimental model was the bcl2 RNA (b-RNA), its molecular mechanisms of degradation and the functional effects of turnover modifications by exogenous means

  18. Does a Corresponding Set of Variables for Explaining Voluntary Organizational Turnover Transfer to Explaining Voluntary Occupational Turnover?

    Science.gov (United States)

    Blau, Gary

    2007-01-01

    This study proposed and tested corresponding sets of variables for explaining voluntary organizational versus occupational turnover for a sample of medical technologists. This study is believed to be the first test of the Rhodes and Doering (1983) occupational change model using occupational turnover data. Results showed that corresponding job…

  19. Vascularization of engineered cartilage constructs in a mouse model.

    Science.gov (United States)

    Burghartz, Marc; Gehrke, Thomas; Storck, Katharina; Staudenmaier, Rainer; Mandlik, Veronika; Schurr, Christian; Hoang, Nguyen; Hagen, Rudolf; Kleinsasser, Norbert

    2015-02-01

    Tissue engineering of cartilage tissue offers a promising method for reconstructing ear, nose, larynx and trachea defects. However, a lack of sufficient nutrient supply to cartilage constructs limits this procedure. Only a few animal models exist to vascularize the seeded scaffolds. In this study, polycaprolactone (PCL)-based polyurethane scaffolds are seeded with 1 × 10(6) human cartilage cells and implanted in the right hind leg of a nude mouse using an arteriovenous flow-through vessel loop for angiogenesis for the first 3 weeks. Equally seeded scaffolds but without access to a vessel loop served as controls. After 3 weeks, a transposition of the vascularized scaffolds into the groin of the nude mouse was performed. Constructs (verum and controls) were explanted 1 and 6 weeks after transposition. Constructs with implanted vessels were well vascularized. The amount of cells increased in vascularized constructs compared to the controls but at the same time noticeably less extracellular matrix was produced. This mouse model provides critical answers to important questions concerning the vascularization of engineered tissue, which offers a viable option for repairing defects, especially when the desired amount of autologous cartilage or other tissues is not available and the nutritive situation at the implantation site is poor. PMID:25381568

  20. Chitosan/Poly(ɛ-caprolactone) blend scaffolds for cartilage repair

    NARCIS (Netherlands)

    Neves, Sara C.; Moreira Teixeira, Liliana S.; Moroni, Lorenzo; Reis, Rui L.; Blitterswijk, van Clemens A.; Alves, Natália M.; Karperien, Marcel; Mano, João F.

    2011-01-01

    Chitosan (CHT)/poly(ɛ-caprolactone) (PCL) blend 3D fiber-mesh scaffolds were studied as possible support structures for articular cartilage tissue (ACT) repair. Micro-fibers were obtained by wet-spinning of three different polymeric solutions: 100:0 (100CHT), 75:25 (75CHT) and 50:50 (50CHT) wt.% CHT

  1. Surgical correction of joint deformities and hyaline cartilage regeneration

    Directory of Open Access Journals (Sweden)

    Vyacheslav Alexandrovich Vinokurov

    2015-12-01

    Full Text Available Aim. To determine a method of extra-articular osteochondral fragment formation for the improvement of surgical correction results of joint deformities and optimization of regenerative conditions for hyaline cartilage. Materials and Methods. The method of formation of an articular osteochondral fragment without penetration into the joint cavity was devised experimentally. More than 30 patients with joint deformities underwent the surgery. Results. During the experiments, we postulated that there may potentially be a complete recovery of joint defects because of hyaline cartilage regeneration. By destructing the osteochondral fragment and reforming it extra-articularally, joint defects were recovered in all patients. The results were evaluated as excellent and good in majority of the patients. Conclusion. These findings indicate a novel method in which the complete recovery of joint defects due to dysplastic genesis or osteochondral defects as a result of injuries can be obtained. The devised method can be used in future experiments for objectification and regenerative potential of hyaline cartilage (e.g., rate and volume of the reformed joints that regenerate, detection of cartilage elements, and the regeneration process.

  2. Holmium laser ablation of cartilage: effects of cavitation bubbles

    Science.gov (United States)

    Asshauer, Thomas; Jansen, Thomas; Oberthur, Thorsten; Delacretaz, Guy P.; Gerber, Bruno E.

    1995-05-01

    The ablation of fresh harvested porcine femur patellar groove cartilage by a 2.12 micrometers Cr:Tm:Ho:YAG laser in clinically used irradiation conditions was studied. Laser pulses were delivered via a 600 micrometers diameter fiber in isotonic saline. Ablation was investigated as a function of the angle of incidence of the delivery fiber with respect to the cartilage surface (0-90 degrees) and of radiant exposure. Laser pulses with energies of 0.5, 1.0 and 1.5 J and a duration of 250 microseconds were used. A constant fiber tip-tissue distance of 1 mm was maintained for all experiments. The dynamics of the induced vapor bubble and of the ablation process was monitored by time resolved flash videography with a 1 microseconds illumination. Acoustic transients were measured with a piezoelectric PVDF needle probe hydrophone. Bubble attachment to the cartilage surface during the collapse phase, leading to the direct exposition of the cartilage surface to the maximal pressure generated, was observed in all investigated irradiation conditions. Maximal pressure transients of up to 200 bars (at 1 mm distance from the collapse center) were measured at the bubble collapse at irradiation angles >= 60 degrees. No significant pressure variation was observed in perpendicular irradiation conditions as a function of radiant exposure. A significant reduction of the induced pressure for irradiation angles

  3. Healing Osteoarthritis: Engineered Proteins Created for Therapeutic Cartilage Regeneration

    Directory of Open Access Journals (Sweden)

    Kevin M. Cherry

    2012-01-01

    Full Text Available Millions of people worldwide are afflicted with painfulosteoarthritis, which is characterized by degradationof articular cartilage found in major joints such as thehip or knee. Symptoms include inflammation, pain,and decreased mobility. Because cartilage has a limitedability to self-heal, researchers have focused efforts onmethods that trigger cartilage regeneration. Our approachis to develop an injectable, protein-based hydrogel withmechanical properties analogous to healthy articularcartilage. The hydrogel provides an environment for cellgrowth and stimulates new tissue formation. We utilizedrecombinant DNA technology to create multifunctional,elastomeric proteins. The recombinant proteins weredesigned with biologically active domains to influence cellbehavior and resilin structural domains that mimic thestiffness of native cartilage. Resilin, a protein found in thewing and leg joints of mosquitoes, provided inspiration forthe mechanical domain in the recombinant protein. Thenew resilin-based protein was expressed in E. coli bacteria.Forming hydrogels requires a large quantity of engineeredprotein, so parameters such as bacterial host, incubationtemperature, expression time, and induction method wereoptimized to increase the protein yield. Using salt toprecipitate the protein and exploiting resilin’s heat stability,27 mg/L of recombinant protein was recovered at 95%purity. The protein expression and purification protocolswere established by analyzing experimental samples onSDS-PAGE gels and by Western blotting. The mechanicalproperties and interactions with stem cells are currentlybeing evaluated to assess the potential of the resilin-basedhydrogel as a treatment for osteoarthritis.

  4. NONINVASIVE DETERMINATION OF KNEE CARTILAGE DEFORMATION DURING JUMPING

    Directory of Open Access Journals (Sweden)

    Djordje Kosanic

    2009-12-01

    Full Text Available The purpose of this investigation was to use a combination of image processing, force measurements and finite element modeling to calculate deformation of the knee cartilage during jumping. Professional athletes performed jumps analyzed using a force plate and high-speed video camera system. Image processing was performed on each frame of video using a color recognition algorithm. A simplified mass-spring-damper model was utilized for determination of global force and moment on the knee. Custom software for fitting the coupling characteristics was created. Simulated results were used as input data for the finite element calculation of cartilage deformation in the athlete's knee. Computer simulation data was compared with the average experimental ground reaction forces. The results show the three-dimensional mechanical deformation distribution inside the cartilage volume. A combination of the image recognition technology, force plate measurements and the finite element cartilage deformation in the knee may be used in the future as an effective noninvasive tool for prediction of injury during jumping

  5. Multinuclear nuclear magnetic resonance spectroscopic study of cartilage proteoglycans

    International Nuclear Information System (INIS)

    Hyaline cartilage is a composite material whose major function is to withstand compression while retaining flexibility. Its mechanical properties are affected by tissue hydration and ionic composition. Models of the mechanical behavior of cartilage have incorporated certain assumptions about the interactions of the major components of cartilage: collagen, proteoglycans, water, and cations. To determine the validity of these assumption, the authors have used nuclear magnetic resonance spectroscopy (NMR). Two approaches have been used: (a) natural abundance carbon-13 NMR; and (b) NMR of sodium-23, potassium-39, magnesium-25, and calcium-43. Evidence from studies in intact tissues are reinforced by extensive measurements on solutions of proteoglycans and other relevant macromolecules. Based on the measurements of NMR relaxation rates and lineshapes reported here, it is concluded that neither sodium nor potassium interact strongly with bovine nasal proteoglycan aggregates or their substituent glycosaminoglycan chains in solution. Proteoglycans do bind magnesium and calcium. Therefore there is a qualitative difference between monovalent and divalent cations, which is not taken into account by polyelectrolyte models or models for the ionic dependence of mechanical properties. Cation binding to heparin, which has a higher charge density than cartilage proteoglycans, was also studied. The results presented here establish that heparin binds sodium, magnesium, and calcium

  6. Human Endogenous Retrovirus W Activity in Cartilage of Osteoarthritis Patients

    Directory of Open Access Journals (Sweden)

    Signy Bendiksen

    2014-01-01

    Full Text Available The etiology of viruses in osteoarthritis remains controversial because the prevalence of viral nucleic acid sequences in peripheral blood or synovial fluid from osteoarthritis patients and that in healthy control subjects are similar. Until now the presence of virus has not been analyzed in cartilage. We screened cartilage and chondrocytes from advanced and non-/early osteoarthritis patients for parvovirus B19, herpes simplex virus-1, Epstein Barr virus, cytomegalovirus, human herpes virus-6, hepatitis C virus, and human endogenous retroviruses transcripts. Endogenous retroviruses transcripts, but none of the other viruses, were detected in 15 out the 17 patients. Sequencing identified the virus as HERV-WE1 and E2. HERV-W activity was confirmed by high expression levels of syncytin, dsRNA, virus budding, and the presence of virus-like particles in all advanced osteoarthritis cartilages examined. Low levels of HERV-WE1, but not E2 envelope RNA, were observed in 3 out of 8 non-/early osteoarthritis patients, while only 3 out of 7 chondrocytes cultures displayed low levels of syncytin, and just one was positive for virus-like particles. This study demonstrates for the first time activation of HERV-W in cartilage of osteoarthritis patients; however, a causative role for HERV-W in development or deterioration of the disease remains to be proven.

  7. Focal changes of the anticular cartilage in the femorotibial joint

    International Nuclear Information System (INIS)

    This paper reports on the value of routine MR sequences in detecting focal changes in the femorotibial hyaline cartilage. T1-, proton density-, and T2-weighted spin-echo and gradient-echo images were acquired in 20 cadaveric knees (cadavers aged 56-88 years; mean, 73.8 years). Three hundred eight coronal and sagittal (3-mm) anatomic sections were prepared, allowing identification of 85 areas of cartilage fissuring, fibrillation, or ulceration. Initially, MR images and anatomic sections were correlated in an unblinded fashion. Subsequently, images of a subset of 35 pathologic and 35 normal cartilage surfaces were blindly evaluated. In the unblinded study, 61 lesions were detectable on T1-weighted images, 59 with meniscal windows, 51 on proton density images, 58 on T2-weighted images, and 57 on gradient-echo images. A fissure usually manifested as a focus of abnormal signal. Ulcers and fibrillation presented as more extensive irregular signal, often accompanied by subchondral sclerosis. In the blinded study, the sensitivity was 71.4% for the detection of focal cartilage changes, the specificity was 68.6%, and the accuracy was 70%. Single fissures and superficial ulcers accounted for the majority of false-negative results

  8. Study on the Microstructure of Human Articular Cartilage/Bone Interface

    Institute of Scientific and Technical Information of China (English)

    Yaxiong Liu; Qin Lian; Jiankang He; Jinna Zhao; Zhongmin Jin; Dichen Li

    2011-01-01

    For improving the theory of gradient microstructure of cartilage/bone interface, human distal femurs were studied. Scanning Electron Microscope (SEM), histological sections and MicroCT were used to observe, measure and model the microstructure of cartilage/bone interface. The results showed that the cartilage/bone interface is in a hierarchical structure which is composed of four different tissue layers. The interlocking of hyaline cartilage and calcified cartilage and that of calcified cartilage and subchondral bone are in the manner of"protrusion-pore" with average diameter of 17.0 μm and 34.1 μm respectively. In addition, the cancellous bone under the cartilage is also formed by four layer hierarchical structure, and the adjacent layers are connected by bone trabecula in the shape of H, I and Y, forming a complex interwoven network structure. Finally, the simplified structure model of the cartilage/bone interface was proposed according to the natural articular cartilage/bone interface. The simplified model is a 4-layer gradient biomimetic structure, which corresponds to four different tissues of natural cartilage/bone interface. The results of this work would be beneficial to the design of bionic scaffold for the tissue engineering of articular cartilage/bone.

  9. Staff turnover in statewide implementation of ACT: relationship with ACT fidelity and other team characteristics

    OpenAIRE

    Rollins, Angela L.; Salyers, Michelle P.; Tsai, Jack; Lydick, Jennifer M.

    2010-01-01

    Staff turnover on assertive community treatment (ACT) teams is a poorly understood phenomenon. This study examined annual turnover and fidelity data collected in a statewide implementation of ACT over a 5-year period. Mean annual staff turnover across all observations was 30.0%. Turnover was negatively correlated with overall fidelity at Year 1 and 3. The team approach fidelity item was negatively correlated with staff turnover at Year 3. For 13 teams with 3 years of follow-up data, turnover ...

  10. Evaluation of nasal cartilage using three-dimensional soft tissue images in patients with unilateral cleft lip

    International Nuclear Information System (INIS)

    In the treatment of nasal deformities associated with cleft lip and palate, deformities of the alar cartilage and upper lateral cartilage are usually repaired. It is very useful if deformities of the nasal cartilage are evaluated preoperatively. We created three-dimensional CT images of soft tissues by the volume rendering method, the nasal cartilage. In 26 patients with unilateral cleft lip and palate, the alar cartilage, upper lateral cartilage, and septal cartilage were evaluated morphologically. As a result, in each case, these cartilages were deviated and deformed. However, the size of both the alar cartilage and the upper lateral cartilage on the cleft side were approximately similar to those on the healthy side. It is suggested that using this method formulated for the imaging of cartilaginous morphology, preoperative planning and follow-up can be performed easily. (author)

  11. A Validated Model of the Pro- and Anti-Inflammatory Cytokine Balancing Act in Articular Cartilage Lesion Formation

    OpenAIRE

    Wang, Xiayi; Brouillette, Marc J.; Ayati, Bruce P; Martin, James A.

    2015-01-01

    Traumatic injuries of articular cartilage result in the formation of a cartilage lesion and contribute to cartilage degeneration and the risk of osteoarthritis (OA). A better understanding of the framework for the formation of a cartilage lesion formation would be helpful in therapy development. Toward this end, we present an age and space-structured model of articular cartilage lesion formation after a single blunt impact. This model modifies the reaction-diffusion-delay models in Graham et ...

  12. Dolichol alters brain membrane functions

    International Nuclear Information System (INIS)

    It has been well demonstrated that there is a direct correlation between increase in dolichol level in brain and aging. An abnormally high level of dolichol was found in brain tissue of patients with pathological aging disorders. The aim of this study is to examine the physiological significance of dolichol affecting membrane transport activity and phospholipid acyl group turnover. Dolichol added to synaptic plasma membranes resulted in a biphasic effect on (Na+, K+)-ATPase, i.e., an enhancement of activity at low concentrations (5 μg/125 mg protein) and an inhibition of activity at high concentrations (40-100 μg). To probe the membrane acyl group turnover, the incorporation of [14C]-arachidonate into plasma membrane phospholipids was examined in the presence and absence of dolichol. Dolichol elicited an increase in the incorporation of label into phospholipids. However, the effects varied depending on whether BSA is present. In the absence of BSA, the increase in labeling of phosphatidylinositols is higher than that of phosphatidylcholines. These results suggest that dolichols, when inserted into membranes, may alter membrane functions

  13. Dolichol alters brain membrane functions

    Energy Technology Data Exchange (ETDEWEB)

    Sun, G.Y.; Sun, A.Y.; Schroeder, F.; Wood, G.; Strong, R.

    1986-03-05

    It has been well demonstrated that there is a direct correlation between increase in dolichol level in brain and aging. An abnormally high level of dolichol was found in brain tissue of patients with pathological aging disorders. The aim of this study is to examine the physiological significance of dolichol affecting membrane transport activity and phospholipid acyl group turnover. Dolichol added to synaptic plasma membranes resulted in a biphasic effect on (Na/sup +/, K/sup +/)-ATPase, i.e., an enhancement of activity at low concentrations (5 ..mu..g/125 mg protein) and an inhibition of activity at high concentrations (40-100 ..mu..g). To probe the membrane acyl group turnover, the incorporation of (/sup 14/C)-arachidonate into plasma membrane phospholipids was examined in the presence and absence of dolichol. Dolichol elicited an increase in the incorporation of label into phospholipids. However, the effects varied depending on whether BSA is present. In the absence of BSA, the increase in labeling of phosphatidylinositols is higher than that of phosphatidylcholines. These results suggest that dolichols, when inserted into membranes, may alter membrane functions.

  14. Understanding the factors that determine registered nurses' turnover intentions.

    Science.gov (United States)

    Osuji, Joseph; Uzoka, Faith-Michael; Aladi, Flora; El-Hussein, Mohammed

    2014-01-01

    Turnover among registered nurses (RNs) produces a negative impact on the health outcomes of any health care organization. It is also recognized universally as a problem in the nursing profession. Little is known about the turnover intentions and career orientations of RNs working in Calgary, Alberta, Canada. The aim of this study is to contribute to the knowledge of and to advance the discussion on the turnover of nursing professionals. The study population consisted of RNs employed in the five major hospitals in Calgary. There were 193 surveys returned, representing a response rate of 77.2%. The results show that age and education have a negative effect on turnover intention. Education was found to have a significant negative effect on career satisfaction but not on job satisfaction and organizational commitment. Length of service has a significant negative effect on turnover intention. Role ambiguity has significant highly negative effect on career satisfaction. Growth opportunity and supervisor support have a very significant positive effect on job satisfaction, career satisfaction, and organizational commitment. External career opportunities and organizational commitment do not seem to have a significant effect on turnover intention. Career satisfaction, on the other hand, had negative significant effects on turnover intention. PMID:25087326

  15. Measurements of protein turnover in man with nitrogen-15

    International Nuclear Information System (INIS)

    Past and present methods of measuring total body protein turnover with 15N-labelled compounds are reviewed, and a short assessment made of results achieved. Protein turnover in man was first measured by Sprinson and Rittenberg (1949) using 15N glycine as tracer. The rate of turnover was calculated from the fraction of the dose excreted in urine in the days following a single oral dose of the isotope. In the following years a number of similar methods were devised but interest waned, perhaps because consistent changes in turnover rate under different conditions were not detected. A revival of interest came with the measurement of changes in protein turnover in malnourished and recovering children by Picou and Taylor-Roberts (1969). Nitrogen-15-glycine was infused and measurements were made of the abundance of 15N in urinary urea, which reached a plateau in about 24 hours. Turnover rates were calculated from the proportion of the infused dose excreted in urea after the plateau had been reached. This method has also been used successfully on adults when the isotope has been given as three-hourly oral doses. In adults, however, plateau labelling in urea is not usually reached for two days. In our laboratory the use of urinary ammonia, which reaches a plateau more quickly than urea, has been examined. In addition, comparisons have been made between constant infusion and single dose of isotope. Halliday and McKeran (1975) infused 15N-lysine and measured the 15N abundance in the free lysine of plasma, which reached a plateau in about 12 hours. Turnover in the whole body and turnover of muscle proteins and of plasma albumin were estimated separately. These methods of measuring protein turnover with 15N are described and results reviewed of the effects of food intake, nutritional status and age. (author)

  16. Higher Dissatisfaction Higher Turnover in the Hospitality Industry

    OpenAIRE

    Ahmad Rasmi AlBattat; Ahmad Puad Mat Som; Abdullah Saleh Helalat

    2014-01-01

    Turnover crisis reducing has been highlighted as a remarkable research theme in the hospitality industry. Regardless of the significant number of studies on employee turnover, it remains a vague issue and requires further research, It is well known that the service industry is highly dependent on the “human factor” which has become a major part of the hospitality product. The aim of this study is to give a clearer idea of enhancing employment factors to reduce the turnover crisis, Mobley`s mo...

  17. A simplified method for the clinical study of protein turnover

    International Nuclear Information System (INIS)

    The determination of turnover rate of serum albumin, or of other serum proteins, may be interesting for clinical purposes because the turnover rates may be changed as one of the consequences of renal, hepatic or gastro-intestinal diseases. Until now, is was not possible to use turnover methods routinely in the clinic, because daily sampling is too tedious for patients and hospital employees. A simplified method of sampling was introduced. This method was then evaluated in order to determine whether or not the results would be significant enough for clinical purposes. 1 tab

  18. Colloidal 234Th and the turnover of oceanic DOC

    International Nuclear Information System (INIS)

    234Th has been proposed to be a tracer for the labile, colloidal fraction of DOC in seawater. During the recent North Atlantic Bloom Experiment (NABE) the turnover of DOC was directly measured. 234Th and total suspended matter (Cp) were also measured by different research groups. Using the NABE 234Th data the authors have calculated the turnover rate of colloidal material using the Brownian Pumping model of Honeyman and Santschi and the 4-box particle cycling model of Moran and Buesseler. The rate constants for colloid cycling determined from the 234Th data agree well with the experimentally determined rate constants for turnover of DOC

  19. Turnover and employment in the German wind energy industry

    International Nuclear Information System (INIS)

    Results of the fast growing wind energy market in 1994 are the turnover reaching more than 800 million DM, and the number of employees to about 3,700. In 1995 the manufacturers expect to need less than 4 employees to build and to install 1 MW rated power and to decrease the ratio of manufacturer's turnover per installed power unit to about 1900 DM/kW. In spite of this development it is expected that the turnover and the number of employees will increase due to the still fast growing market. (orig.)

  20. Turnover Rate of Popularity Charts in Neutral Models

    CERN Document Server

    Evans, T S

    2011-01-01

    It has been shown recently that in many different cultural phenomena the turnover rate on the most popular artefacts in a population exhibit some regularities. A very simple expression for this turnover rate has been proposed by Bentley et al. and its validity in two simple models for copying and innovation is investigated in this paper. It is found that Bentley's formula is an approximation of the real behaviour of the turnover rate in the Wright-Fisher model, while it is not valid in the Moran model.

  1. Procyanidin B3 prevents articular cartilage degeneration and heterotopic cartilage formation in a mouse surgical osteoarthritis model.

    Directory of Open Access Journals (Sweden)

    Hailati Aini

    Full Text Available Osteoarthritis (OA is a common disease in the elderly due to an imbalance in cartilage degradation and synthesis. Heterotopic ossification (HO occurs when ectopic masses of endochondral bone form within the soft tissues around the joints and is triggered by inflammation of the soft tissues. Procyanidin B3 (B3 is a procyanidin dimer that is widely studied due to its high abundance in the human diet and antioxidant activity. Here, we evaluated the role of B3 isolated from grape seeds in the maintenance of chondrocytes in vitro and in vivo. We observed that B3 inhibited H(2O(2-induced apoptosis in primary chondrocytes, suppressed H(2O(2- or IL-1ß-induced nitric oxide synthase (iNOS production, and prevented IL-1ß-induced suppression of chondrocyte differentiation marker gene expression in primary chondrocytes. Moreover, B3 treatment enhanced the early differentiation of ATDC5 cells. To examine whether B3 prevents cartilage destruction in vivo, OA was surgically induced in C57BL/6J mice followed by oral administration of B3 or vehicle control. Daily oral B3 administration protected articular cartilage from OA and prevented chondrocyte apoptosis in surgically-induced OA joints. Furthermore, B3 administration prevented heterotopic cartilage formation near the surgical region. iNOS protein expression was enhanced in the synovial tissues and the pseudocapsule around the surgical region in OA mice fed a control diet, but was reduced in mice that received B3. Together, these data indicated that in the OA model, B3 prevented OA progression and heterotopic cartilage formation, at least in a part through the suppression of iNOS. These results support the potential therapeutic benefits of B3 for treatment of human OA and heterotopic ossification.

  2. Hsp90 inhibition decreases mitochondrial protein turnover.

    Directory of Open Access Journals (Sweden)

    Daciana H Margineantu

    Full Text Available BACKGROUND: Cells treated with hsp90 inhibitors exhibit pleiotropic changes, including an expansion of the mitochondrial compartment, accompanied by mitochondrial fragmentation and condensed mitochondrial morphology, with ultimate compromise of mitochondrial integrity and apoptosis. FINDINGS: We identified several mitochondrial oxidative phosphorylation complex subunits, including several encoded by mtDNA, that are upregulated by hsp90 inhibitors, without corresponding changes in mRNA abundance. Post-transcriptional accumulation of mitochondrial proteins observed with hsp90 inhibitors is also seen in cells treated with proteasome inhibitors. Detailed studies of the OSCP subunit of mitochondrial F1F0-ATPase revealed the presence of mono- and polyubiquitinated OSCP in mitochondrial fractions. We demonstrate that processed OSCP undergoes retrotranslocation to a trypsin-sensitive form associated with the outer mitochondrial membrane. Inhibition of proteasome or hsp90 function results in accumulation of both correctly targeted and retrotranslocated mitochondrial OSCP. CONCLUSIONS: Cytosolic turnover of mitochondrial proteins demonstrates a novel connection between mitochondrial and cytosolic compartments through the ubiquitin-proteasome system. Analogous to defective protein folding in the endoplasmic reticulum, a mitochondrial unfolded protein response may play a role in the apoptotic effects of hsp90 and proteasome inhibitors.

  3. μ-XRF and μ-XANES at calcification fronts of human articular cartilage

    International Nuclear Information System (INIS)

    Full text: One of the main threats to human health from heavy metals is associated with exposure to lead (Pb), which is associated with chronic diseases in the nervous, hematopoietic, skeletal, renal and endocrine system. Although much progress has been made to limit Pb exposure in industrialized countries, primarily through the elimination of leaded gasoline, workplace exposures and leaded pipes, most adults have already accumulated a substantial body burden of Pb. Most of the affiliated Pb is deposited in human bones, where it is stored up to 20 years and accounts for 90.95 of the total lead body burden. Pb is able to displace Ca2+ by cation exchange processes in the hydroxyapatite crystal (the main constituent of bone) and is liberated from it in cases of increased bone turnover such as osteoporosis, pregnancy, hyperthyroidism and hyperparathyroidism. Besides these phenomenological studies on the release of Pb from human calcified tissue analytical studies are essential to gain insight on storage sites and storage mechanisms on a microscopic scale. Therefore detailed synchrotron radiation induced micro x-ray fluorescence analyses (SR μ - XRF) have been carried out to study the distribution of Pb in bones from human joints (femoral heads and patellas). As a very recent result we found a highly specific accumulation of Pb in the tidemark, which is a metabolically active mineralization front (thickness about 5 - 10 μm) between calcified and non-calcified articular cartilage and plays an important role in developing osteoarthritis. From the results obtained for single tidemark bones one would expect an accumulation of Pb in both tidemarks of bones showing tidemark duplication. However, Pb shows a strong accumulation at the older of the two tidemarks, while it is not present at the younger one. A comparison of the Pb distribution with the one of other tidemark-seekers (e.g. Zn) exhibits a time difference in the accumulation of different metals at the calcification

  4. Multiparametric MRI of Epiphyseal Cartilage Necrosis (Osteochondrosis with Histological Validation in a Goat Model.

    Directory of Open Access Journals (Sweden)

    Luning Wang

    Full Text Available To evaluate multiple MRI parameters in a surgical model of osteochondrosis (OC in goats.Focal ischemic lesions of two different sizes were induced in the epiphyseal cartilage of the medial femoral condyles of goats at 4 days of age by surgical transection of cartilage canal blood vessels. Goats were euthanized and specimens harvested 3, 4, 5, 6, 9 and 10 weeks post-op. Ex vivo MRI scans were conducted at 9.4 Tesla for mapping the T1, T2, T1ρ, adiabatic T1ρ and TRAFF relaxation times of articular cartilage, unaffected epiphyseal cartilage, and epiphyseal cartilage within the area of the induced lesion. After MRI scans, safranin O staining was conducted to validate areas of ischemic necrosis induced in the medial femoral condyles of six goats, and to allow comparison of MRI findings with the semi-quantitative proteoglycan assessment in corresponding safranin O-stained histological sections.All relaxation time constants differentiated normal epiphyseal cartilage from lesions of ischemic cartilage necrosis, and the histological staining results confirmed the proteoglycan (PG loss in the areas of ischemia. In the scanned specimens, all of the measured relaxation time constants were higher in the articular than in the normal epiphyseal cartilage, consistently allowing differentiation between these two tissues.Multiparametric MRI provided a sensitive approach to discriminate between necrotic and viable epiphyseal cartilage and between articular and epiphyseal cartilage, which may be useful for diagnosing and monitoring OC lesions and, potentially, for assessing effectiveness of treatment interventions.

  5. Strain ratio measurement of femoral cartilage by real-time elastosonography: preliminary results

    Energy Technology Data Exchange (ETDEWEB)

    Ipek, Ali; Unal, Ozlem; Kartal, Merve Gulbiz; Arslan, Halil [Yildirim Beyazit University, Department of Radiology, Faculty of Medicine, Ataturk Training and Research Hospital, Ankara (Turkey); Isik, Cetin; Bozkurt, Murat [Yildirim Beyazit University, Department of Orthopedics, Faculty of Medicine, Ataturk Training and Research Hospital, Ankara (Turkey)

    2015-04-01

    The purpose of this study was to evaluate strain ratio measurement of femoral cartilage using real-time elastosonography. Twenty-five patients with femoral cartilage pathology on MRI (study group) were prospectively compared with 25 subjects with normal findings on MRI (control group) using real-time elastosonography. Strain ratio measurements of pathologic and normal cartilage were performed and compared, both within the study group and between the two groups. Elastosonography colour-scale coding showed a colour change from blue to red in pathologic cartilage and only blue colour-coding in normal cartilage. In the study group, the median strain ratio was higher in pathologic cartilage areas compared to normal areas (median, 1.49 [interquartile range, 0.80-2.53] vs. median, 0.01 [interquartile range, 0.01-0.01], p < 0.001, respectively). The median strain ratio of the control group was 0.01 (interquartile range, 0.01-0.01), and there was no significant difference compared to normal areas of the study group. There was, however, a significant difference between the control group cartilage and pathologic cartilage of the study group (p < 0.001). Elastosonography may be an effective, easily accessible, and relatively simple tool to demonstrate pathologic cartilage and to differentiate it from normal cartilage in the absence of advanced imaging facility such as MRI. (orig.)

  6. T2 star relaxation times for assessment of articular cartilage at 3 T: a feasibility study

    Energy Technology Data Exchange (ETDEWEB)

    Mamisch, Tallal Charles [University Bern, Department of Orthopedic Surgery, Inselspital, Bern (Switzerland); University Bern, Magnetic Resonance Spectroscopy and Methodology, Department of Clinical Research, Bern (Switzerland); Hughes, Timothy [Siemens Medical Solutions, Erlangen (Germany); Mosher, Timothy J. [Penn State University College of Medicine, Musculoskeletal Imaging and MRI, Department of Radiology, Hershey, PA (United States); Mueller, Christoph [University of Erlangen, Department of Trauma Surgery, Erlangen (Germany); Trattnig, Siegfried [Medical University of Vienna, MR Center - High Field MR, Department of Radiology, Vienna (Austria); Boesch, Chris [University Bern, Magnetic Resonance Spectroscopy and Methodology, Department of Clinical Research, Bern (Switzerland); Welsch, Goetz Hannes [University of Erlangen, Department of Trauma Surgery, Erlangen (Germany); Medical University of Vienna, MR Center - High Field MR, Department of Radiology, Vienna (Austria)

    2012-03-15

    T2 mapping techniques use the relaxation constant as an indirect marker of cartilage structure, and the relaxation constant has also been shown to be a sensitive parameter for cartilage evaluation. As a possible additional robust biomarker, T2* relaxation time is a potential, clinically feasible parameter for the biochemical evaluation of articular cartilage. The knees of 15 healthy volunteers and 15 patients after microfracture therapy (MFX) were evaluated with a multi-echo spin-echo T2 mapping technique and a multi-echo gradient-echo T2* mapping sequence at 3.0 Tesla MRI. Inline maps, using a log-linear least squares fitting method, were assessed with respect to the zonal dependency of T2 and T2* relaxation for the deep and superficial regions of healthy articular cartilage and cartilage repair tissue. There was a statistically significant correlation between T2 and T2* values. Both parameters demonstrated similar spatial dependency, with longer values measured toward the articular surface for healthy articular cartilage. No spatial variation was observed for cartilage repair tissue after MFX. Within this feasibility study, both T2 and T2* relaxation parameters demonstrated a similar response in the assessment of articular cartilage and cartilage repair tissue. The potential advantages of T2*-mapping of cartilage include faster imaging times and the opportunity for 3D acquisitions, thereby providing greater spatial resolution and complete coverage of the articular surface. (orig.)

  7. Characterization of pediatric microtia cartilage: a reservoir of chondrocytes for auricular reconstruction using tissue engineering strategies.

    Science.gov (United States)

    Melgarejo-Ramírez, Y; Sánchez-Sánchez, R; García-López, J; Brena-Molina, A M; Gutiérrez-Gómez, C; Ibarra, C; Velasquillo, C

    2016-09-01

    The external ear is composed of elastic cartilage. Microtia is a congenital malformation of the external ear that involves a small reduction in size or a complete absence. The aim of tissue engineering is to regenerate tissues and organs clinically implantable based on the utilization of cells and biomaterials. Remnants from microtia represent a source of cells for auricular reconstruction using tissue engineering. To examine the macromolecular architecture of microtia cartilage and behavior of chondrocytes, in order to enrich the knowledge of this type of cartilage as a cell reservoir. Auricular cartilage remnants were obtained from pediatric patients with microtia undergoing reconstructive procedures. Extracellular matrix composition was characterized using immunofluorescence and histological staining methods. Chondrocytes were isolated and expanded in vitro using a mechanical-enzymatic protocol. Chondrocyte phenotype was analyzed using qualitative PCR. Microtia cartilage preserves structural organization similar to healthy elastic cartilage. Extracellular matrix is composed of typical cartilage proteins such as type II collagen, elastin and proteoglycans. Chondrocytes displayed morphological features similar to chondrocytes derived from healthy cartilage, expressing SOX9, COL2 and ELN, thus preserving chondral phenotype. Cell viability was 94.6 % during in vitro expansion. Elastic cartilage from microtia has similar characteristics, both architectural and biochemical to healthy cartilage. We confirmed the suitability of microtia remnant as a reservoir of chondrocytes with potential to be expanded in vitro, maintaining phenotypical features and viability. Microtia remnants are an accessible source of autologous cells for auricular reconstruction using tissue engineering strategies. PMID:27566509

  8. Autofluorescence lifetime metrology for label-free detection of cartilage matrix degradation

    Science.gov (United States)

    Nickdel, Mohammad B.; Lagarto, João. L.; Kelly, Douglas J.; Manning, Hugh B.; Yamamoto, Kazuhiro; Talbot, Clifford B.; Dunsby, Christopher; French, Paul; Itoh, Yoshifumi

    2014-03-01

    Degradation of articular cartilage extracellular matrix (ECM) by proteolytic enzyme is the hallmark of arthritis that leads to joint destruction. Detection of early biochemical changes in cartilage before irreversible structural damages become apparent is highly desirable. Here we report that the autofluorescence decay profile of cartilage is significantly affected by proteolytic degradation of cartilage ECM and can be characterised by measurements of the autofluorescence lifetime (AFL). A multidimensional fluorometer utilizing ultraviolet excitation at 355 nm or 375 nm coupled to a fibreoptic probe was developed for single point time-resolved AFL measurements of porcine articular cartilage explants treated with different proteinases. Degradation of cartilage matrix components by treating with bacterial collagenase, matrix metalloproteinase 1, or trypsin resulted in significant reduction of AFL of the cartilage in both a dose and time dependent manner. Differences in cartilage AFL were also confirmed by fluorescence lifetime imaging microscopy (FLIM). Our data suggest that AFL of cartilage tissue is a potential non-invasive readout to monitor cartilage matrix integrity that may be utilized for diagnosis of arthritis as well as monitoring the efficacy of anti-arthritic therapeutic agents.

  9. T2 star relaxation times for assessment of articular cartilage at 3 T: a feasibility study

    International Nuclear Information System (INIS)

    T2 mapping techniques use the relaxation constant as an indirect marker of cartilage structure, and the relaxation constant has also been shown to be a sensitive parameter for cartilage evaluation. As a possible additional robust biomarker, T2* relaxation time is a potential, clinically feasible parameter for the biochemical evaluation of articular cartilage. The knees of 15 healthy volunteers and 15 patients after microfracture therapy (MFX) were evaluated with a multi-echo spin-echo T2 mapping technique and a multi-echo gradient-echo T2* mapping sequence at 3.0 Tesla MRI. Inline maps, using a log-linear least squares fitting method, were assessed with respect to the zonal dependency of T2 and T2* relaxation for the deep and superficial regions of healthy articular cartilage and cartilage repair tissue. There was a statistically significant correlation between T2 and T2* values. Both parameters demonstrated similar spatial dependency, with longer values measured toward the articular surface for healthy articular cartilage. No spatial variation was observed for cartilage repair tissue after MFX. Within this feasibility study, both T2 and T2* relaxation parameters demonstrated a similar response in the assessment of articular cartilage and cartilage repair tissue. The potential advantages of T2*-mapping of cartilage include faster imaging times and the opportunity for 3D acquisitions, thereby providing greater spatial resolution and complete coverage of the articular surface. (orig.)

  10. Tracheal cartilage regeneration and new bone formation by slow release of bone morphogenetic protein (BMP)-2.

    Science.gov (United States)

    Igai, Hitoshi; Chang, Sung Soo; Gotoh, Masashi; Yamamoto, Yasumichi; Yamamoto, Masaya; Tabata, Yasuhiko; Yokomise, Hiroyasu

    2008-01-01

    We investigated the efficiency of bone morphogenetic protein (BMP)-2 released slowly from gelatin sponge for tracheal cartilage regeneration. A 1-cm gap was made in the mid-ventral portion of each of 10 consecutive tracheal cartilages. In the control group (n = 4), the resulting gap was left untreated. In the gelatin group (n = 4), plain gelatin was implanted in the gap. In the BMP-2 group (n = 4), gelatin containing 100 microg BMP-2 was implanted. We euthanatized all dogs in each group at 1, 3, 6, and 12 months after the implantation, respectively, and then examined the implant site macro- and microscopically. In the BMP-2 group, regenerated fibrous cartilage and newly formed bone were observed at 1 and 12 months. Regenerated cartilage was observed at the ends of the host cartilage stumps, with newly formed bone in the middle portion. The gaps were filled with regenerated cartilage and newly formed bone. At 3 and 6 months, regenerated cartilage, but not newly formed bone, was evident. The regenerated cartilage was covered with perichondrium and showed continuity with the host cartilage. We succeeded in inducing cartilage regeneration and new bone formation in canine trachea by slow release of 100 microg BMP-2 from gelatin. PMID:18204324

  11. PREVALENCE OF LARYNGEAL CARTILAGE CALCIFICATIONS IN MANGALORE POPULATION; A RADIOGRAPHIC STUDY

    Directory of Open Access Journals (Sweden)

    Nandita Shenoy

    2014-10-01

    Full Text Available Soft tissue calcifications in the orofacial region are uncommon and are usually asymptomatic in nature. Some of the common calcifications found are Carotid artery calcifications (CAC, Triticeous cartilage, and Superior cornu of the thyroid cartilage, Tonsilloliths and lymph nodes calcifications. Disordered ossification or calcification of ligaments or cartilages may compress neurovascular structures, may be able to cause serious implications in any surgical intervention in the region, may lead to false neurological differential diagnosis or may be benign in nature without any clinical significance. Ossification and calcification of the laryngeal cartilages have been widely investigated since the original study by Chievitz in 1882 1 . The thyroid, cricoid, and greater part of the arytenoid cartilages consist of hyaline cartilage that undergoes calcification and ossification as part of the ageing process. The thyroid cartilage tends to be visible on the cephalometric and lateral neck radiograph when the ossification starts within the lamina or either of the cornua. The cricoids and arytenoid cartilages also become apparent when the ossification begins within their laminae. Radiographs of the head and neck are used to study the growth and development of skeletal structures can be used for identification of these calcifications 2 . A good understanding of the anatomy and the knowledge of variations in the laryngeal cartilage ossification is important for all clinicians especially while interpreting head and neck radiographs of patients who exhibit anatomical or functional deviations from the normal. The lateral cephalometric radiographs are advised more commonly by an orthodontist to look for occlusion and lateral profile of the patient pre and post orthodontic treatment. They also demonstrate the posterosuperior part of the lamina, and the superior cornu of the thyroid cartilage. Laryngeal and related cartilages like the cricoid and triticeal

  12. Articular Cartilage Evaluation After TruFit Plug Implantation Analyzed by Delayed Gadolinium-Enhanced MRI of Cartilage (dGEMRIC)

    NARCIS (Netherlands)

    Bekkers, J.E.J.; Bartels, L.W.; Vincken, K.L.; Dhert, W.J.A.; Creemers, L.B.; Saris, D.B.F.

    2013-01-01

    Background: Quantitative MRI of articular cartilage has rapidly developed in recent years and provides the clinician with a noninvasive tool to determine the biological consequence of an intervention. Purpose: To evaluate the quality of intra-articular cartilage, using the dGEMRIC scanning techniqu

  13. Rapid adjustment in chrysanthemum carbohydrate turnover and growth activity to a change in time-of-day application of light and daylength

    DEFF Research Database (Denmark)

    Kjær, Katrine Heinsvig; Poiré, Richard; Ottosen, Carl-Otto;

    2012-01-01

    with an onset of a daily starch turnover by a shift to short days. These results confirm findings from model species on the complex relationship between carbohydrate metabolism, source–sink relations and growth rate and they shed new light on the dynamic processes during acclimation towards altered...... diurnally-regulated parameters related to growth. In this study, chrysanthemum plants were exposed to a change in the time-of-day application of light followed by short days or long days with a night interruption of light. We observed a clear shift in the diel cycle of sucrose turnover and relative leaf...

  14. Wind energy industry in Germany. Turnover and employment

    International Nuclear Information System (INIS)

    As a consequence of the growing wind energy market in Germany the importance of the industry in this business are has grown. In 1994 the turnover will go beyond 500 million DM, and the number of employees will reach 2,900. The turnover and the number of employees are increasing in spite of the higher efficiency. In 1994 only 5 employees are needed by a manufacturer to install 1 MW rated power instead of 15 in 1989, and the ratio of installed power to manufacturer's turnover has risen from 0,25 W/DM in 1988 to 0,455 W/DM in 1994. On the other hand the turnover of the manufacturers per employee has increased from 80,000 DM in 1988 to 440,000 DM in 1994. Economic development has considerably been advanced by subsidies for the application of wind energy technology. (orig.)

  15. Company Training Reduces Employee Turnover, or Does It?

    Directory of Open Access Journals (Sweden)

    Connie Zheng

    2009-04-01

    Full Text Available Prior empirical studies tend to suggest that company training and employee skill development, together with other human resource (HR management practices lead to high employee commitment and low labour turnover rate. Using the data collected from multinational companies operating in eight economies (Chile, Indonesia, Malaysia, Mexico, Philippines, Singapore, Taiwan and Thailand located in the Asia Pacific region, we ran a multiple regress model and found that company training is significantly related to employee turnover, however it does not contribute to the reduction of the employee turnover rate.  Other organisational factors (eg. size, parent source and expatriation presentation in the local subsidiary played more significant role in determining the level of employee turnover, particularly for the companies in the international operation.  The implications of the study are discussed.

  16. Autoradiographic imaging of phosphoinositide turnover in the brain

    International Nuclear Information System (INIS)

    With [3H]cytidine as a precursor, phosphoinositide turnover can be localized in brain slices by selective autoradiography of the product [3H]cytidine diphosphate diacylglycerol, which is membrane-bound. In the cerebellum, glutamatergic stimulation elicits an increase of phosphoinositide turnover only in Purkinje cells and the molecular layer. In the hippocampus, both glutamatergic and muscarinic cholinergic stimulation increase phosphoinositide turnover, but with distinct localizations. Cholinergic stimulation affects CA1, CA3, CA4, and subiculum, whereas glutamatergic effects are restricted to the subiculum and CA3. Imaging phosphoinositide turnover in brain slices, which are amenable to electrophysiologic studies, will permit a dynamic localized analysis of regulation of this second messenger in response to synaptic stimulation of specific neuronal pathways

  17. The Relationship Between Job Satisfaction and Turnover Intention

    Directory of Open Access Journals (Sweden)

    Ahmad Faisal Mahdi

    2012-01-01

    Full Text Available Problem statement: The objective of this study were to determine the effect of job satisfaction on turnover intentions among the employees in XYZ Sdn. Bhd, Malaysia. Approach: A total of 32 set of complete questionnaires gathered from executives and non-executives of a local printing company were involved in the study and 32 completed the questionnaires. Using structured questionnaires in a controlled environment, the results manage to extract both intrinsic and extrinsic job satisfaction that influences the turnover intention. Results: The statistical results obtained in this study showed that both forms of job satisfaction (intrinsic and extrinsic satisfaction have inverse relationship on employees’ turnover intentions. Conclusion: Eventhough Instrinsic Job Satisfaction have stronger influence on Turnover Intention. Existence of Extrinstic Job Satisfaction also must be consider in measuring the intention.

  18. Investigating Occupational Commitment and Turnover Intention Relationship with Burnout Syndrome

    Directory of Open Access Journals (Sweden)

    Aydem Ciftcioglu

    2011-07-01

    Full Text Available This study investigates burnout components impact on accountant’s occupational commitment and occupational turnover intention interaction. The data used in this study was taken from randomly selected 162 accountants who are the members of Istanbul Chambers of Certified Public Accountants (ICCPA. The results reveal that only emotional exhaustion component of burnout has partial mediating effect between affective occupational commitment and occupational turnover intention.

  19. Effects of New Goods and Product Turnover on Price Indexes

    OpenAIRE

    Abe, Naohito; Enda, Toshiki; Inakura, Noriko; TONOGI Akiyuki

    2015-01-01

    This study analyzes the importance of new products for price measurements. Using large-scale retail scanner data in Japan, we construct a unit value price index and decompose its fluctuation into (1) standard price change effects, (2) substitution effects within continuing goods, and (3) turnover-new product effects. The aggregate unit price index exhibits different movements from the standard Laspeyres price index. After the 2014 change in Japan's tax rate, turnover-new product effects from ...

  20. Does Perceived Support in Employee Development Affect Personnel Turnover?

    OpenAIRE

    Koster Fleur; Grip Andries de; Fouarge Didier

    2009-01-01

    This paper focuses on the question whether it is beneficial for firms to invest in the general skills of their workforce or that these training investments merely encourage personnel turnover. We examine two contrary theoretical perspectives on how investments in employee development are related to their turnover behaviour. Estimation results derived from a sample of 2,833 Dutch pharmacy assistants show that participation in general training does not induce the intention of assistants to quit...

  1. Study on Decision Support System of Employee Turnover Risk Management

    OpenAIRE

    Xiang Liu

    2009-01-01

    Employee turnover risk is becoming an important aspect that influences the stability and development of enterprises in the times of knowledge economy. After analyzing the factors of employee turnover risk which would threaten enterprise production and operation activities, a decision support system in this field will be proposed, and it is realized by message processing mechanism, software combination technology and system integration. Also, the corresponding management strategies were set up...

  2. Stock-Based Compensation and Top Management Turnover

    OpenAIRE

    Hamid Mehran; David Yermack

    1996-01-01

    We test the hypothesis that corporate managers leave their jobs less often when they receive stock-based compensation. In a sample of CEOs from 452 large U.S. companies between 1984 and 1991, we find inverse associations between the probability of CEO turnover and the amount of stock option compensation in relation to cash pay. The association is even stronger when we exclude apparently involuntary CEO turnover. Our results suggest that stock-based compensation plays a significant role in hel...

  3. Kramers Turnover Theory for a Triple Well Potential

    International Nuclear Information System (INIS)

    Kramers turnover theory is solved for a particle in a symmetric triple well potential for temperatures above the crossover temperature between tunneling and activated barrier crossing. Comparison with the turnover theory for a double well potential shows that the presence of the intermediate well always leads to a decrease of the reaction rate. At most though, the rate is a factor of two smaller than in the case of a double well potential. (author)

  4. Turnover of nursing employees in a Gauteng hospital group

    OpenAIRE

    Japie Greyling; Karel Stanz

    2010-01-01

    Orientation: The South African nursing profession is in a crisis as professional nurses leave the country in search of lucrative work overseas.Research purpose: The purpose of this study was to investigate individual determinants of voluntary turnover to identify a risk-group profile.Motivation for the study: Nursing employers should have a clearer understanding of the dynamics around nurses’ turnover behaviour and embark on strategies to retain their talent.Research design, approach and meth...

  5. Adipocyte triglyceride turnover and lipolysis in lean and overweight subjects.

    OpenAIRE

    Ryden, M; Andersson, D. P.; Bernard, S.; Spalding, K.; Arner, P

    2013-01-01

    Human obesity is associated with decreased triglyceride turnover and impaired lipolysis in adipocytes. We determined whether such defects also occur in subjects with only moderate increase in fat mass. Human abdominal subcutaneous adipose tissue was investigated in healthy, nonobese subjects [body mass index (BMI) > 17 kg/m2 and BMI < 30 kg/m2]. Triglyceride age, reflecting lipid turnover, was examined in 41 subjects by assessing the incorporation of atmospheric 14C into adipose lipids. Adipo...

  6. Excess turnover and employment growth: firm and match heterogeneity

    OpenAIRE

    Centeno, Mário; Machado, Carla; Novo, Álvaro A.

    2009-01-01

    Portuguese firms engage in intense reallocation, most employers simultaneously hire and separate from workers, resulting in a large heterogeneity of flows and excess turnover. Large and older firms have lower flows, but high excess turnover rates. In small firms, hires and separations move symmetrically during expansion and contraction periods, on the contrary, large firms adjust their employment levels by reducing entry and not by increasing separations. Most hires and separations are on fix...

  7. Turnover intention among new nurses: a generational perspective.

    Science.gov (United States)

    Lavoie-Tremblay, Melanie; Paquet, Maxime; Marchionni, Caroline; Drevniok, Ulrika

    2011-01-01

    With the current nursing shortage, it is crucial to understand the aspects of the nursing work environment that are related to turnover in new generation nurses. The Practice Environment Scale of the Nursing Work Index was administered to new nurses in Quebec from different generations to determine what domains of the work environment were related to turnover intention. Results can help nurses in leadership and development positions target interventions to retain new graduates. PMID:21263280

  8. Pengaruh Job Insecurity Terhadap Turnover Intentions Pada Pegawai Perusahaan Merger

    OpenAIRE

    Pane, Deasy Anggreini

    2014-01-01

    Merge is one of a strategy to expand business networks in a short time. One of the psychological impact of merge is job insecurity. Individu who experience prolonged in job insecurity has a rational reason to seek other job alternatives. This research was aimed to examine the effect of job insecurity toward turnover intentions. Data were gathered from 49 employees of the merger company and used purposive sampling method. The data were collected by using job insecurity scale and turnover inten...

  9. Radiological, computertomographic, pathoanatomical and histological examination of the rib cartilage of the dog

    International Nuclear Information System (INIS)

    This study was concerned with the representation and description of the rib cartilage of the dog and the abnormalities of such by means of radiological, computer tomographic, pathoanatomical and histological examinations and the comparison of the results of the various examination methods. The study material consisted of 100 ventral thorax walls of dogs of different ages and breeds. In 39 of the subjects, no abnormalities of rib cartilage other than unremarkable calcification were observed. Among the subjects, there were 11 puppies (0-3 months), whose rib cartilage appeared soft tissue dense due to the absence of calcification, 14 juvenile animals (4-18 months), the rib cartilage of which showed a typical finely granulated structure, and 14 adult dogs (over 18 months), whose rib cartilage exhibited a homogeneous to net-like calcified appearance. In the calcified rib cartilage, the histological section showed a centrally located spongiosa rod surrounded by a hyaline cartilage shell. The calcification tendency of the first pair of rib cartilage was remarkable: in 70 dogs, the first pair of rib cartilage remained uncalcified despite calcification of the other rib cartilage. Sixty-one dogs exhibited rib cartilage abnormalities. According to the radiological appearance of the abnormalities, they were divided into groups and their incidence was calculated. Abnormalities seen included interruption in the continuity of the calcified rib cartilage with and without callus formation, enlargement of rib cartilage, cuff formation, and abnormalities on the Articulationes sternocostales (projections in or around articulations, calcified and fractured joint surfaces). In addition, remarkable calcification patterns were observed. By means of CT examination the densities of the tissue forming the various abnormalities was determined. In the course of the pathoanatomical examination, it was shown that the interruptions in continuity with callus and the various enlarged areas of the

  10. A stem cell-based approach to cartilage repair.

    Science.gov (United States)

    Johnson, Kristen; Zhu, Shoutian; Tremblay, Matthew S; Payette, Joshua N; Wang, Jianing; Bouchez, Laure C; Meeusen, Shelly; Althage, Alana; Cho, Charles Y; Wu, Xu; Schultz, Peter G

    2012-05-11

    Osteoarthritis (OA) is a degenerative joint disease that involves the destruction of articular cartilage and eventually leads to disability. Molecules that promote the selective differentiation of multipotent mesenchymal stem cells (MSCs) into chondrocytes may stimulate the repair of damaged cartilage. Using an image-based high-throughput screen, we identified the small molecule kartogenin, which promotes chondrocyte differentiation (median effective concentration = 100 nM), shows chondroprotective effects in vitro, and is efficacious in two OA animal models. Kartogenin binds filamin A, disrupts its interaction with the transcription factor core-binding factor β subunit (CBFβ), and induces chondrogenesis by regulating the CBFβ-RUNX1 transcriptional program. This work provides new insights into the control of chondrogenesis that may ultimately lead to a stem cell-based therapy for osteoarthritis. PMID:22491093

  11. Reviewing Employee Turnover: Focusing on Proximal Withdrawal States and an Expanded Criterion

    Science.gov (United States)

    Hom, Peter W.; Mitchell, Terence R.; Lee, Thomas W.; Griffeth, Rodger W.

    2012-01-01

    We reconceptualize employee turnover to promote researchers' understanding and prediction of why employees quit or stay in employing institutions. A literature review identifies shortcomings with prevailing turnover dimensions. In response, we expand the conceptual domain of the turnover criterion to include multiple types of turnover (notably,…

  12. The Cost of Teacher Turnover in Five School Districts: A Pilot Study

    Science.gov (United States)

    Barnes, Gary; Crowe, Edward: Schaefer, Benjamin

    2007-01-01

    In this paper, we report the results of a pilot study of the cost of teacher turnover in five school districts. We examine the rate of turnover, the relationship between turnover and teacher and school characteristics, and the costs associated with recruiting, hiring, and training replacement teachers. We find evidence that turnover costs,…

  13. Explaining the Gap in Charter and Traditional Public School Teacher Turnover Rates

    Science.gov (United States)

    Stuit, David A.; Smith, Thomas M.

    2012-01-01

    This study uses national survey data to examine why charter school teachers are more likely to turnover than their traditional public school counterparts. We test whether the turnover gap is explained by different distributions of factors that are empirically and theoretically linked to turnover risk. We find that the turnover rate of charter…

  14. Absence of correlation between rates of cell wall turnover and autolysis shown by Bacillus subtilis mutants.

    OpenAIRE

    Vitković, L; Cheung, H. Y.; Freese, E

    1984-01-01

    Bacillus subtilis mutants with reduced rates of cell wall autolysis reached a constant rate of wall turnover after a longer lag than the standard strain but eventually showed the same turnover rate. In reverse, a turnover-deficient mutant autolysed at a slightly higher rate than the standard strain. Consequently, there is no correlation between the rates of cell wall turnover and autolysis.

  15. Smectite alteration

    International Nuclear Information System (INIS)

    This report contains the proceedings of a second workshop in Washington DC December 8-9, 1983 on the alteration of smectites intended for use as buffer materials in the long-term containment of nuclear wastes. It includes extended summaries of all presentations and a transcript of the detailed scientific discussion. The discussions centered on three main questions: What is the prerequisite for and what is the precise mechanism by which smectite clays may be altered to illite. What are likly sources of potassium with respect to the KBS project. Is it likely that the conversion of smectite to illite will be of importance in the 10 5 to the 10 6 year time frame. The workshop was convened to review considerations and conclusions in connection to these questions and also to broaden the discussion to consider the use of smectite clays as buffer materials for similar applications in different geographical and geological settings. SKBF/KBS technical report 83-03 contains the proceedings from the first workshop on these matters that was held at the State University of New York, Buffalo May 26-27, 1982. (Author)

  16. Biochemical Characterization of Normal Navicular Bone Flexor Surface Cartilage

    OpenAIRE

    Vits, Lucia Carolina

    2002-01-01

    Cartilage tissue specimens were obtained from the flexor surface of the navicular bone and distal radiocarpal bone articular surface (controls) from 8 horses 2 to 5 years old. Water, DNA, total collagen, total glycosaminoglycans, chondroitin sulphate, and keratan sulphate contents were determined. The results from each site were compared and the differences were analyzed by paired t-test (P < 0.05). Significant differences were determined between the water content of the navicular bon...

  17. Hyaluronic Acid-Binding Scaffold for Articular Cartilage Repair

    OpenAIRE

    Unterman, Shimon A.; Gibson, Matthew; Lee, Janice H.; Crist, Joshua; Chansakul, Thanissara; Yang, Elaine C.; Jennifer H. Elisseeff

    2012-01-01

    Hyaluronic acid (HA) is an extracellular matrix molecule with multiple physical and biological functions found in many tissues, including cartilage. HA has been incorporated in a number of biomaterial and scaffold systems. Howegver, HA in the material may be difficult to control if it is not chemically modified and chemical modification of HA may negatively impact biological function. In this study, we developed a poly(ethylene glycol) hydrogel with noncovalent HA-binding capabilities and eva...

  18. Advances in the Surgical Management of Articular Cartilage Defects

    OpenAIRE

    Stein, Spencer; Strauss, Eric; Bosco, Joseph

    2013-01-01

    Objective: The purpose of this review is to gain insight into the latest methods of articular cartilage implantation (ACI) and to detail where they are in the Food and Drug Administration approval and regulatory process. Design: A PubMed search was performed using the phrase “Autologous Chondrocyte Implantation” alone and with the words second generation and third generation. Additionally, clinicaltrials.gov was searched for the names of the seven specific procedures and the parent company we...

  19. Human sclera maintains common characteristics with cartilage throughout evolution.

    Directory of Open Access Journals (Sweden)

    Yuko Seko

    Full Text Available BACKGROUND: The sclera maintains and protects the eye ball, which receives visual inputs. Although the sclera does not contribute significantly to visual perception, scleral diseases such as refractory scleritis, scleral perforation and pathological myopia are considered incurable or difficult to cure. The aim of this study is to identify characteristics of the human sclera as one of the connective tissues derived from the neural crest and mesoderm. METHODOLOGY/PRINCIPAL FINDINGS: We have demonstrated microarray data of cultured human infant scleral cells. Hierarchical clustering was performed to group scleral cells and other mesenchymal cells into subcategories. Hierarchical clustering analysis showed similarity between scleral cells and auricular cartilage-derived cells. Cultured micromasses of scleral cells exposed to TGF-betas and BMP2 produced an abundant matrix. The expression of cartilage-associated genes, such as Indian hedge hog, type X collagen, and MMP13, was up-regulated within 3 weeks in vitro. These results suggest that human 'sclera'-derived cells can be considered chondrocytes when cultured ex vivo. CONCLUSIONS/SIGNIFICANCE: Our present study shows a chondrogenic potential of human sclera. Interestingly, the sclera of certain vertebrates, such as birds and fish, is composed of hyaline cartilage. Although the human sclera is not a cartilaginous tissue, the human sclera maintains chondrogenic potential throughout evolution. In addition, our findings directly explain an enigma that the sclera and the joint cartilage are common targets of inflammatory cells in rheumatic arthritis. The present global gene expression database will contribute to the clarification of the pathogenesis of developmental diseases such as high myopia.

  20. Tissue Engineering of Muscles and Cartilages Using Polyelectrolyte Hydrogels

    OpenAIRE

    Hyuck Joon Kwon

    2014-01-01

    The prevalent nature of osteoarthritis that causes the erosion of joint surfaces and loss of mobility and muscle dystrophy that weakens the musculoskeletal system and hampers locomotion underlies the importance of developing functional replacement or regeneration of muscle and cartilage tissues. Polyelectrolyte gels have high potential as cellular scaffolds due to characteristic properties similar to biological matrixes. A number of in vitro and in vivo studies demonstrated that polyelectroly...