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Sample records for engineering custom-designed osteochondral

  1. Osteochondral tissue engineering: current strategies and challenges.

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    Nukavarapu, Syam P; Dorcemus, Deborah L

    2013-01-01

    Osteochondral defect management and repair remain a significant challenge in orthopedic surgery. Osteochondral defects contain damage to both the articular cartilage as well as the underlying subchondral bone. In order to repair an osteochondral defect the needs of the bone, cartilage and the bone-cartilage interface must be taken into account. Current clinical treatments for the repair of osteochondral defects have only been palliative, not curative. Tissue engineering has emerged as a potential alternative as it can be effectively used to regenerate bone, cartilage and the bone-cartilage interface. Several scaffold strategies, such as single phase, layered, and recently graded structures have been developed and evaluated for osteochondral defect repair. Also, as a potential cell source, tissue specific cells and progenitor cells are widely studied in cell culture models, as well with the osteochondral scaffolds in vitro and in vivo. Novel factor strategies being developed, including single factor, multi-factor, or controlled factor release in a graded fashion, not only assist bone and cartilage regeneration, but also establish osteochondral interface formation. The field of tissue engineering has made great strides, however further research needs to be carried out to make this strategy a clinical reality. In this review, we summarize current tissue engineering strategies, including scaffold design, bioreactor use, as well as cell and factor based approaches and recent developments for osteochondral defect repair. In addition, we discuss various challenges that need to be addressed in years to come. Copyright © 2012 Elsevier Inc. All rights reserved.

  2. Mesenchymal Stem Cells for Osteochondral Tissue Engineering.

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    Ng, Johnathan; Bernhard, Jonathan; Vunjak-Novakovic, Gordana

    2016-01-01

    Mesenchymal stem cells (MSC) are of major interest in regenerative medicine, as they are easily harvested from a variety of sources (including bone marrow and fat aspirates) and they are able to form a range of mesenchymal tissues, in vitro and in vivo. We focus here on the use of MSCs for engineering of cartilage, bone, and complex osteochondral tissue constructs, using protocols that replicate some aspects of natural mesodermal development. For engineering of human bone, we discuss some of the current advances, and highlight the use of perfusion bioreactors for supporting anatomically exact human bone grafts. For engineering of human cartilage, we discuss the limitations of current approaches, and highlight engineering of stratified, mechanically functional human cartilage interfaced with bone by mesenchymal condensation of MSCs. Taken together, current advances enable engineering of physiologically relevant bone, cartilage and osteochondral composites, and physiologically relevant studies of osteochondral development and disease.

  3. Porous titanium bases for osteochondral tissue engineering

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    Nover, Adam B.; Lee, Stephanie L.; Georgescu, Maria S.; Howard, Daniel R.; Saunders, Reuben A.; Yu, William T.; Klein, Robert W.; Napolitano, Anthony P.; Ateshian, Gerard A.

    2015-01-01

    Tissue engineering of osteochondral grafts may offer a cell-based alternative to native allografts, which are in short supply. Previous studies promote the fabrication of grafts consisting of a viable cell-seeded hydrogel integrated atop a porous, bone-like metal. Advantages of the manufacturing process have led to the evaluation of porous titanium as the bone-like base material. Here, porous titanium was shown to support the growth of cartilage to produce native levels of Young’s modulus, using a clinically relevant cell source. Mechanical and biochemical properties were similar or higher for the osteochondral constructs compared to chondral-only controls. Further investigation into the mechanical influence of the base on the composite material suggests that underlying pores may decrease interstitial fluid pressurization and applied strains, which may be overcome by alterations to the base structure. Future studies aim to optimize titanium-based tissue engineered osteochondral constructs to best match the structural architecture and strength of native grafts. Statement of Significance The studies described in this manuscript follow up on previous studies from our lab pertaining to the fabrication of osteochondral grafts that consist of a bone-like porous metal and a chondrocyte-seeded hydrogel. Here, tissue engineered osteochondral grafts were cultured to native stiffness using adult chondrocytes, a clinically relevant cell source, and a porous titanium base, a material currently used in clinical implants. This porous titanium is manufactured via selective laser melting, offering the advantages of precise control over shape, pore size, and orientation. Additionally, this manuscript describes the mechanical influence of the porous base, which may have applicability to porous bases derived from other materials. PMID:26320541

  4. [Research progress of construction of tissue engineered osteochondral composites].

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    Zhang, Yongtao; Jin, Dan

    2011-09-01

    To review the recent progress of the researches in construction of tissue engineered osteochondral composites, and to discuss the challenges in construction of tissue engineered osteochondral composites. The recent literature on the construction of tissue engineered osteochondral composites was extensively reviewed and analyzed. The studies on the construction of tissue engineered osteochondral composites are relatively more in vivo, the current focus is that different tissues derived mesenchymal stem cells are widely used to be seed cells; single-phase scaffold has been limited, studies on biphase scaffold and triphase scaffold are new trends; the design and performance of bioreactor need to be further optimized in the future. The construction of tissue engineered osteochondral composites will be a promising method for the treatment of cartilage defects.

  5. Tissue engineering of osteochondral constructs in vitro using bioreactors.

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    Haasper, Carl; Zeichen, Johannes; Meister, Roland; Krettek, Christian; Jagodzinski, Michael

    2008-04-01

    Articular cartilage is a relatively simple tissue, but has a limited capacity of restoration. Tissue engineering is a promising field that seeks to accomplish the in vitro generation of complex, functional, 3-dimensional tissues. Various cell types and scaffolds have been tested for these purposes. The results of tissue engineered cartilage and bone are as yet inferior to native tissue. Strain and perfusion have been shown to stimulate cell proliferation and differentiation of various cell phenotypes. The perfect protocol to produce articular cartilage has not been defined yet. Bioreactors could provide the environment to engineer osteochondral constructs in vitro and to provide a stress protocol. The bioreactor has to provide an economically viable approach to automated manufacture of functional grafts under clinical aspects. Composite engineered tissues, like an engineered joint, represent a future goal. Cross-disciplinary approaches are necessary in order to succeed in engineering osteochondral grafts that provide adequate primary biomechanical stability and incorporate rapidly in vivo with histological appearance close to healthy osteochondral tissue. This review surveys current clinical and experimental concepts and discusses challenges and future expectations in this advancing field of regenerative medicine focusing human osteochondral constructs in bioreactors.

  6. Cell-laden hydrogels for osteochondral and cartilage tissue engineering.

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    Yang, Jingzhou; Zhang, Yu Shrike; Yue, Kan; Khademhosseini, Ali

    2017-07-15

    Despite tremendous advances in the field of regenerative medicine, it still remains challenging to repair the osteochondral interface and full-thickness articular cartilage defects. This inefficiency largely originates from the lack of appropriate tissue-engineered artificial matrices that can replace the damaged regions and promote tissue regeneration. Hydrogels are emerging as a promising class of biomaterials for both soft and hard tissue regeneration. Many critical properties of hydrogels, such as mechanical stiffness, elasticity, water content, bioactivity, and degradation, can be rationally designed and conveniently tuned by proper selection of the material and chemistry. Particularly, advances in the development of cell-laden hydrogels have opened up new possibilities for cell therapy. In this article, we describe the problems encountered in this field and review recent progress in designing cell-hydrogel hybrid constructs for promoting the reestablishment of osteochondral/cartilage tissues. Our focus centers on the effects of hydrogel type, cell type, and growth factor delivery on achieving efficient chondrogenesis and osteogenesis. We give our perspective on developing next-generation matrices with improved physical and biological properties for osteochondral/cartilage tissue engineering. We also highlight recent advances in biomanufacturing technologies (e.g. molding, bioprinting, and assembly) for fabrication of hydrogel-based osteochondral and cartilage constructs with complex compositions and microarchitectures to mimic their native counterparts. Despite tremendous advances in the field of regenerative medicine, it still remains challenging to repair the osteochondral interface and full-thickness articular cartilage defects. This inefficiency largely originates from the lack of appropriate tissue-engineered biomaterials that replace the damaged regions and promote tissue regeneration. Cell-laden hydrogel systems have emerged as a promising tissue-engineering

  7. Repair of osteochondral defects with allogeneic tissue engineered cartilage implants.

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    Schreiber, R E; Ilten-Kirby, B M; Dunkelman, N S; Symons, K T; Rekettye, L M; Willoughby, J; Ratcliffe, A

    1999-10-01

    The objective of this study was to evaluate the effect of allogeneic tissue engineered cartilage implants on healing of osteochondral defects. Rabbit chondrocytes were cultured in monolayer, then seeded onto biodegradable, three-dimensional polyglycolic acid meshes. Cartilage constructs were cultured hydrodynamically to yield tissue with relatively more (mature) or less (immature) hyalinelike cartilage, as compared with adult rabbit articular cartilage. Osteochondral defects in the patellar grooves of both stifle joints either were left untreated or implanted with allogeneic tissue engineered cartilage. Histologic samples from in and around the defect sites were examined 3, 6, 9, and 12, and 24 months after surgery. By 9 months after surgery, defects sites treated with cartilage implants contained significantly greater amounts of hyalinelike cartilage with high levels of proteoglycan, and had a smooth, nonfibrillated articular surface as compared to untreated defects. In contrast, the repair tissue formed in untreated defects had fibrillated articular surfaces, significant amounts of fibrocartilage, and negligible proteoglycan. These differences between treated and untreated defects persisted through 24 months after surgery. The results of this study suggest that the treatment of osteochondral lesions with allogenic tissue engineered cartilage implants may lead to superior repair tissue than that found in untreated osteochondral lesions.

  8. 3D Bioprinting for Cartilage and Osteochondral Tissue Engineering.

    Science.gov (United States)

    Daly, Andrew C; Freeman, Fiona E; Gonzalez-Fernandez, Tomas; Critchley, Susan E; Nulty, Jessica; Kelly, Daniel J

    2017-11-01

    Significant progress has been made in the field of cartilage and bone tissue engineering over the last two decades. As a result, there is real promise that strategies to regenerate rather than replace damaged or diseased bones and joints will one day reach the clinic however, a number of major challenges must still be addressed before this becomes a reality. These include vascularization in the context of large bone defect repair, engineering complex gradients for bone-soft tissue interface regeneration and recapitulating the stratified zonal architecture present in many adult tissues such as articular cartilage. Tissue engineered constructs typically lack such spatial complexity in cell types and tissue organization, which may explain their relatively limited success to date. This has led to increased interest in bioprinting technologies in the field of musculoskeletal tissue engineering. The additive, layer by layer nature of such biofabrication strategies makes it possible to generate zonal distributions of cells, matrix and bioactive cues in 3D. The adoption of biofabrication technology in musculoskeletal tissue engineering may therefore make it possible to produce the next generation of biological implants capable of treating a range of conditions. Here, advances in bioprinting for cartilage and osteochondral tissue engineering are reviewed. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Multilayered Scaffolds for Osteochondral Tissue Engineering Based on Bioactive Glass and Biodegradable Polymers

    OpenAIRE

    Nooeaid, Patcharakamon

    2014-01-01

    Injuries of the articular cartilage may penetrate to the underlying subchondral bone, forming osteochondral defects which have a limited capacity of self-regeneration. Accompanied with limited surgical treatments and the fact that the causes are not understood well, an approach based in tissue engineering becomes a promising strategy for osteochondral repair. Such tissue engineering approaches are based on the combination of synthetic scaffolds, suitable cell sources and active molecules or g...

  10. Challenges in engineering osteochondral tissue grafts with hierarchical structures.

    Science.gov (United States)

    Gadjanski, Ivana; Vunjak-Novakovic, Gordana

    2015-01-01

    A major hurdle in treating osteochondral (OC) defects is the different healing abilities of two types of tissues involved - articular cartilage and subchondral bone. Biomimetic approaches to OC-construct engineering, based on recapitulation of biological principles of tissue development and regeneration, have potential for providing new treatments and advancing fundamental studies of OC tissue repair. This review on state of the art in hierarchical OC tissue graft engineering is focused on tissue engineering approaches designed to recapitulate the native milieu of cartilage and bone development. These biomimetic systems are discussed with relevance to bioreactor cultivation of clinically sized, anatomically shaped human cartilage/bone constructs with physiologic stratification and mechanical properties. The utility of engineered OC tissue constructs is evaluated for their use as grafts in regenerative medicine, and as high-fidelity models in biological research. A major challenge in engineering OC tissues is to generate a functionally integrated stratified cartilage-bone structure starting from one single population of mesenchymal cells, while incorporating perfusable vasculature into the bone, and in bone-cartilage interface. To this end, new generations of advanced scaffolds and bioreactors, implementation of mechanical loading regimens and harnessing of inflammatory responses of the host will likely drive the further progress.

  11. Bioreactor-based engineering of osteochondral grafts: from model systems to tissue manufacturing.

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    Wendt, David; Jakob, Marcel; Martin, Ivan

    2005-11-01

    Osteochondral defects (i.e., those that affect both the articular cartilage and underlying subchondral bone) are often associated with mechanical instability of the joint, and therefore with the risk of inducing osteoarthritic degenerative changes. The in vitro fabrication of osteochondral grafts of predefined size and shape, starting from autologous cells combined with three-dimensional porous biomaterials, is a promising approach for the treatment of osteochondral defects. However, the quality of ex vivo generated cartilage and bone-like tissues is currently restricted by a limited understanding of the regulatory role of physicochemical culture parameters on tissue development. By allowing reproducible and controlled changes in specific biochemical and biomechanical factors, bioreactor systems provide the technological means to reveal fundamental mechanisms of cell function in a three-dimensional environment and the potential to improve the quality of engineered tissues. In addition, by automating and standardizing the manufacturing process in controlled closed systems, bioreactors could reduce production costs and thus facilitate broader clinical impact of engineered osteochondral grafts.

  12. Repairing the Osteochondral Defect in Goat with the Tissue-Engineered Osteochondral Graft Preconstructed in a Double-Chamber Stirring Bioreactor

    Directory of Open Access Journals (Sweden)

    Yang Pei

    2014-01-01

    Full Text Available To investigate the reparative efficacy of tissue-engineered osteochondral (TEO graft for repairing the osteochondral defect in goat, we designed a double-chamber stirring bioreactor to construct the bone and cartilage composites simultaneously in one β-TCP scaffold and observed the reparative effect in vivo. The osteochondral defects were created in goats and all the animals were divided into 3 groups randomly. In groups A, the defect was treated with the TEO which was cultured with mechanical stimulation of stir; in group B, the defect was treated with TEO which was cultured without mechanical stimulation of stir; in groups C, the defect was treated without TEO. At 12 weeks and 24 weeks after operation, the reparative effects in different groups were assessed and compared. The results indicated that the reparative effect of the TEO cultured in the bioreactor was better than the control group, and mechanical stimulation of stir could further improve the reparative effect. We provided a feasible and effective method to construct the TEO for treatment of osteochondral defect using autologous BMSCs and the double-chamber bioreactor.

  13. Mechanical loading regulates human MSC differentiation in a multi-layer hydrogel for osteochondral tissue engineering.

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    Steinmetz, Neven J; Aisenbrey, Elizabeth A; Westbrook, Kristofer K; Qi, H Jerry; Bryant, Stephanie J

    2015-07-01

    A bioinspired multi-layer hydrogel was developed for the encapsulation of human mesenchymal stem cells (hMSCs) as a platform for osteochondral tissue engineering. The spatial presentation of biochemical cues, via incorporation of extracellular matrix analogs, and mechanical cues, via both hydrogel crosslink density and externally applied mechanical loads, were characterized in each layer. A simple sequential photopolymerization method was employed to form stable poly(ethylene glycol)-based hydrogels with a soft cartilage-like layer of chondroitin sulfate and low RGD concentrations, a stiff bone-like layer with high RGD concentrations, and an intermediate interfacial layer. Under a compressive load, the variation in hydrogel stiffness within each layer produced high strains in the soft cartilage-like layer, low strains in the stiff bone-like layer, and moderate strains in the interfacial layer. When hMSC-laden hydrogels were cultured statically in osteochondral differentiation media, the local biochemical and matrix stiffness cues were not sufficient to spatially guide hMSC differentiation after 21 days. However dynamic mechanical stimulation led to differentially high expression of collagens with collagen II in the cartilage-like layer, collagen X in the interfacial layer and collagen I in the bone-like layer and mineral deposits localized to the bone layer. Overall, these findings point to external mechanical stimulation as a potent regulator of hMSC differentiation toward osteochondral cellular phenotypes. Copyright © 2015 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  14. Tissue engineering of human cartilage and osteochondral composites using recirculation bioreactors.

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    Mahmoudifar, Nastaran; Doran, Pauline M

    2005-12-01

    Chondrocytes isolated from human foetal epiphyseal cartilage were seeded dynamically into polyglycolic acid (PGA) scaffolds and cultured in recirculation column bioreactors to produce tissue-engineered cartilage. Several culture techniques with the potential to provide endogenous growth factors and other conditions beneficial for de novo cartilage synthesis were investigated. Osteochondral composite constructs were generated by seeding separate PGA scaffolds with either foetal chondrocytes or foetal osteoblasts then suturing the scaffolds together before bioreactor cultivation. This type of co-culture system provided direct contact between the tissue-engineered cartilage and developing tissue-engineered bone and yielded significant improvements in cartilage quality. In the cartilage section of the composites, the concentrations of glycosaminoglycan (GAG) and total collagen were increased by 55% and 2.5-fold, respectively, compared with control cartilage cultures, while levels of collagen type II were similar to those in the controls. The osteochondral composites were harvested from the bioreactors as single units with good integration between the cartilage and bone tissues. Only the cartilage layer contained GAG while only the bone layer was mineralised. In other experiments, co-culture of tissue-engineered cartilage with pieces of ex-vivo cartilage or ex-vivo bone did not improve the quality of the cartilage relative to control cultures. Addition of 10(-6) M diacerein to the culture medium also had no effect on the properties of engineered cartilage. This work demonstrates the beneficial effects of generating cartilage tissues in contact with developing bone. It also demonstrates the feasibility of producing composite osteochondral constructs for clinical application using recirculation column bioreactors.

  15. Restore a 9 mm diameter osteochondral defect with gene enhanced tissue engineering followed mosaicplasty in a goat model

    Directory of Open Access Journals (Sweden)

    Jun Sun

    2016-08-01

    Conclusion: Gene enhanced tissue engineering followed mosaicplasty could restore a 9 mm diameter osteochondral defects in a goat model effectively. With the reduction of covering area of the graft, the advantages of the combined gene enhanced tissue engineering method can be better reflected.

  16. Injectable and 3D Bioprinted Polysaccharide Hydrogels: From Cartilage to Osteochondral Tissue Engineering.

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    Radhakrishnan, Janani; Subramanian, Anuradha; Krishnan, Uma Maheswari; Sethuraman, Swaminathan

    2017-01-09

    Biomechanical performance of functional cartilage is executed by the exclusive anisotropic composition and spatially varying intricate architecture in articulating ends of diarthrodial joint. Osteochondral tissue constituting the articulating ends comprise superfical soft cartilage over hard subchondral bone sandwiching interfacial soft-hard tissue. The shock-absorbent, lubricating property of cartilage and mechanical stability of subchondral bone regions are rendered by extended chemical structure of glycosaminoglycans and mineral deposition, respectively. Extracellular matrix glycosaminoglycans analogous polysaccharides are major class of hydrogels investigated for restoration of functional cartilage. Recently, injectable hydrogels have gained momentum as it offers patient compliance, tunable mechanical properties, cell deliverability, and facile administration at physiological condition with long-term functionality and hyaline cartilage construction. Interestingly, facile modifiable functional groups in carbohydrate polymers impart tailorability of desired physicochemical properties and versatile injectable chemistry for the development of highly potent biomimetic in situ forming scaffold. The scaffold design strategies have also evolved from single component to bi- or multilayered and graded constructs with osteogenic properties for deep subchondral regeneration. This review highlights the significance of polysaccharide structure-based functions in engineering cartilage tissue, injectable chemistries, strategies for combining analogous matrices with cells/stem cells and biomolecules and multicomponent approaches for osteochondral mimetic constructs. Further, the rheology and precise spatiotemporal positioning of cells in hydrogel bioink for rapid prototyping of complex three-dimensional anisotropic cartilage have also been discussed.

  17. Distraction osteogenesis combined with tissue-engineered cartilage in the reconstruction of condylar osteochondral defect.

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    Yu, Hongbo; Yang, Xin; Cheng, Jie; Wang, Xudong; Shen, Steve Guofang

    2011-12-01

    Surgical rehabilitation of condylar osteochondral defect remains a challenge for surgeons. The aim of this study was to explore the feasibility of combining distraction osteogenesis with tissue-engineered cartilage in the reconstruction of condylar osteochondral defect. A condylar defect model was established in 18 goats that were randomly divided into 2 groups: the experimental group and the control group. Mandibular ramus osteotomies were performed and distractors were implanted in all animals. The mixture of chondrocytes and Pluronic F-127 (Sigma-Aldrich, St Louis, MO) was injected on the notched surface of a transport disc in the experimental group, whereas a scaffold without cells was transplanted into the control group. After a 5-day latency period, distraction was activated at a rate of 0.5 mm twice per day for 15 days. The goats were killed at the end of the fourth, eighth, or twelfth week in the consolidation period. Specimens were harvested and macroscopic evaluation, as well as Masson trichrome and immunohistochemical staining, were performed to compare the results between the 2 groups. Osteogenesis was found in all animals with no evidence of infection. Condyle-like structures were formed at the upper end of the transport segment in all animals. The neocondylar surface was covered with a layer of smooth lustrous fibrocartilage in the experimental group. Collagen was shown in the reparative tissue by Masson trichrome staining. Immunohistochemistry staining indicated that type II collagen was positive, whereas type I collagen was negative on the neocondylar surface in the experimental group. No cartilage-like tissue was seen, but fibrous tissue was identified at the bony surface in the control group. In the experimental group, immunofluorescent semiquantitative analysis showed that the positive rate of type II collagen was 1.62% ± 0.53% after the fourth week of consolidation, and it increased to 12.39% ± 3.27% after the twelfth week. There was a

  18. Challenges in engineering osteochondral tissue grafts with hierarchical structures Ivana Gadjanski, Gordana Vunjak Novakovic

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    Gadjanski, Ivana; Vunjak-Novakovic, Gordana

    2015-01-01

    Introduction A major hurdle in treating osteochondral (OC) defects are the different healing abilities of two types of tissues involved - articular cartilage and subchondral bone. Biomimetic approaches to OC-construct-engineering, based on recapitulation of biological principles of tissue development and regeneration, have potential for providing new treatments and advancing fundamental studies of OC tissue repair. Areas covered This review on state of the art in hierarchical OC tissue graft engineering is focused on tissue engineering approaches designed to recapitulate the native milieu of cartilage and bone development. These biomimetic systems are discussed with relevance to bioreactor cultivation of clinically sized, anatomically shaped human cartilage/bone constructs with physiologic stratification and mechanical properties. The utility of engineered OC tissue constructs is evaluated for their use as grafts in regenerative medicine, and as high-fidelity models in biological research. Expert opinion A major challenge in engineering OC tissues is to generate a functionally integrated stratified cartilage-bone structure starting from one single population of mesenchymal cells, while incorporating perfusable vasculature into the bone, and in bone-cartilage interface. To this end, new generations of advanced scaffolds and bioreactors, implementation of mechanical loading regimens, and harnessing of inflammatory responses of the host will likely drive the further progress. PMID:26195329

  19. CARTILAGE CONSTRUCTS ENGINEERED FROM CHONDROCYTES OVEREXPRESSING IGF-I IMPROVE THE REPAIR OF OSTEOCHONDRAL DEFECTS IN A RABBIT MODEL

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    Madry, Henning; Kaul, Gunter; Zurakowski, David; Vunjak-Novakovic, Gordana; Cucchiarini, Magali

    2015-01-01

    Tissue engineering combined with gene therapy is a promising approach for promoting articular cartilage repair. Here, we tested the hypothesis that engineered cartilage with chondrocytes over expressing a human insulin-like growth factor I (IGF-I) gene can enhance the repair of osteochondral defects, in a manner dependent on the duration of cultivation. Genetically modified chondrocytes were cultured on biodegradable polyglycolic acid scaffolds in dynamic flow rotating bioreactors for either 10 or 28 d. The resulting cartilaginous constructs were implanted into osteochondral defects in rabbit knee joints. After 28 weeks of in vivo implantation, immunoreactivity to ß-gal was detectable in the repair tissue of defects that received lacZ constructs. Engineered cartilaginous constructs based on IGF-I-over expressing chondrocytes markedly improved osteochondral repair compared with control (lacZ) constructs. Moreover, IGF-I constructs cultivated for 28 d in vitro significantly promoted osteochondral repair vis-à-vis similar constructs cultivated for 10 d, leading to significantly decreased osteoarthritic changes in the cartilage adjacent to the defects. Hence, the combination of spatially defined overexpression of human IGF-I within a tissue-engineered construct and prolonged bioreactor cultivation resulted in most enhanced articular cartilage repair and reduction of osteoarthritic changes in the cartilage adjacent to the defect. Such genetically enhanced tissue engineering provides a versatile tool to evaluate potential therapeutic genes in vivo and to improve our comprehension of the development of the repair tissue within articular cartilage defects. Insights gained with additional exploration using this model may lead to more effective treatment options for acute cartilage defects. PMID:23588785

  20. Tissue-engineered fabrication of an osteochondral composite graft using rat bone marrow-derived mesenchymal stem cells.

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    Gao, J; Dennis, J E; Solchaga, L A; Awadallah, A S; Goldberg, V M; Caplan, A I

    2001-08-01

    This study tested the tissue engineering hypothesis that construction of an osteochondral composite graft could be accomplished using multipotent progenitor cells and phenotype-specific biomaterials. Rat bone marrow-derived mesenchymal stem cells (MSCs) were culture-expanded and separately stimulated with transforming growth factor-beta1 (TGF-beta1) for chondrogenic differentiation or with an osteogenic supplement (OS). MSCs exposed to TGF-beta1 were loaded into a sponge composed of a hyaluronan derivative (HYAF-11) for the construction of the cartilage component of the composite graft, and MSCs exposed to OS were loaded into a porous calcium phosphate ceramic component for bone formation. Cell-loaded HYAFF-11 sponge and ceramic were joined together with fibrin sealant, Tisseel, to form a composite osteochondral graft, which was then implanted into a subcutaneous pocket in syngeneic rats. Specimens were harvested at 3 and 6 weeks after implantation, examined with histology for morphologic features, and stained immunohistochemically for type I, II, and X collagen. The two-component composite graft remained as an integrated unit after in vivo implantation and histologic processing. Fibrocartilage was observed in the sponge, and bone was detected in the ceramic component. Observations with polarized light indicated continuity of collagen fibers between the ceramic and HYAFF-11 components in the 6-week specimens. Type I collagen was identified in the neo-tissue in both sponge and ceramic, and type II collagen in the fibrocartilage, especially the pericellular matrix of cells in the sponge. These data suggest that the construction of a tissue-engineered composite osteochondral graft is possible with MSCs and different biomaterials and bioactive factors that support either chondrogenic or osteogenic differentiation.

  1. Osteochondritis Dissecans

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    ... Overview Osteochondritis dissecans (os-tee-o-kon-DRY-tis DIS-uh-kanz) is a joint condition in ... Discovery's Edge Magazine Search Publications Training Grant Positions Education Mayo Clinic College of Medicine and Science Mayo ...

  2. Tissue-engineering strategies to repair chondral and osteochondral tissue in osteoarthritis: use of mesenchymal stem cells.

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    Grässel, Susanne; Lorenz, Julia

    2014-10-01

    Focal chondral or osteochondral lesions can be painful and disabling because they have insufficient intrinsic repair potential, and constitute one of the major extrinsic risk factors for osteoarthritis (OA). Attention has, therefore, been paid to regenerative therapeutic procedures for the early treatment of cartilaginous defects. Current treatments for OA are not regenerative and have little effect on the progressive degeneration of joint tissue. One major reason for this underrepresentation of regenerative therapy is that approaches to treating OA with cell-based strategies have to take into consideration the larger sizes of the defects, as compared with isolated focal articular-cartilage defects, and the underlying disease process. Here, we review current treatment strategies using mesenchymal stem cells (MSCs) for chondral and osteochondral tissue repair in trauma and OA-affected joints. We discuss tissue-engineering approaches, in preclinical large-animal models and clinical studies in humans, which use crude bone-marrow aspirates and MSCs from different tissue sources in combination with bioactive agents and materials.

  3. Sol gel-derived hydroxyapatite films over porous calcium polyphosphate substrates for improved tissue engineering of osteochondral-like constructs.

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    Lee, Whitaik David; Gawri, Rahul; Pilliar, Robert M; Stanford, William L; Kandel, Rita A

    2017-10-15

    Integration of in vitro-formed cartilage on a suitable substrate to form tissue-engineered implants for osteochondral defect repair is a considerable challenge. In healthy cartilage, a zone of calcified cartilage (ZCC) acts as an intermediary for mechanical force transfer from soft to hard tissue, as well as an effective interlocking structure to better resist interfacial shear forces. We have developed biphasic constructs that consist of scaffold-free cartilage tissue grown in vitro on, and interdigitated with, porous calcium polyphosphate (CPP) substrates. However, as CPP degrades, it releases inorganic polyphosphates (polyP) that can inhibit local mineralization, thereby preventing the formation of a ZCC at the interface. Thus, we hypothesize that coating CPP substrate with a layer of hydroxyapatite (HA) might prevent or limit this polyP release. To investigate this we tested both inorganic or organic sol-gel processing methods, asa barrier coating on CPP substrate to inhibit polyP release. Both types of coating supported the formation of ZCC in direct contact with the substrate, however the ZCC appeared more continuous in the tissue formed on the organic HA sol gel coated CPP. Tissues formed on coated substrates accumulated comparable quantities of extracellular matrix and mineral, but tissues formed on organic sol-gel (OSG)-coated substrates accumulated less polyP than tissues formed on inorganic sol-gel (ISG)-coated substrates. Constructs formed with OSG-coated CPP substrates had greater interfacial shear strength than those formed with ISG-coated and non-coated substrates. These results suggest that the OSG coating method can modify the location and distribution of ZCC and can be used to improve the mechanical integrity of tissue-engineered constructs formed on porous CPP substrates. Articular cartilage interfaces with bone through a zone of calcified cartilage. This study describes a method to generate an "osteochondral-like" implant that mimics this

  4. Comparison of 2 Different Formulations of Artificial Bone for a Hybrid Implant With a Tissue-Engineered Construct Derived From Synovial Mesenchymal Stem Cells: A Study Using a Rabbit Osteochondral Defect Model.

    Science.gov (United States)

    Shimomura, Kazunori; Moriguchi, Yu; Nansai, Ryosuke; Fujie, Hiromichi; Ando, Wataru; Horibe, Shuji; Hart, David A; Gobbi, Alberto; Yoshikawa, Hideki; Nakamura, Norimasa

    2017-03-01

    Previously, we developed a hybrid implant composed of hydroxyapatite (HA)-based artificial bone coupled with a mesenchymal stem cell (MSC)-based scaffold-free tissue-engineered construct (TEC) and demonstrated its feasibility for osteochondral repair. Beta-tricalcium phosphate (βTCP) may be a promising alternative to HA, as it is a highly biocompatible material and is resorbed more rapidly than HA in vivo. A βTCP-based hybrid TEC implant will exhibit superior osteochondral repair when directly compared with an HA-based hybrid implant, as tested using a rabbit osteochondral defect model. Controlled laboratory study. Osteochondral defects were created in the femoral groove of skeletally mature rabbits. The TEC and artificial bone, using either HA or βTCP with the same porosities and similar mechanical properties, were hybridized and then implanted in the defects. A histological evaluation and microindentation testing were performed for the assessment of repair tissue. Osteochondral defects treated with the TEC/βTCP implants showed more rapid subchondral bone repair at 1 month, but the cartilaginous tissue deteriorated over time out to 6 months after implantation. Osteochondral defects treated with the TEC/HA implants maintained good histological quality out to 6 months after implantation and also exhibited better biomechanical properties at 6 months as compared with the TEC/βTCP implants. Contrary to our hypothesis, the TEC/HA hybrid implant facilitated better osteochondral repair than did the TEC/βTCP implant. The results of the present study suggest the importance of a stable restoration of subchondral bone for long-term effective osteochondral repair rather than rapid remodeling of subchondral bone. This study contributes to the future selection of suitable materials for patients with osteochondral lesions.

  5. Microsphere-Based Hierarchically Juxtapositioned Biphasic Scaffolds Prepared from Poly(Lactic-co-Glycolic Acid and Nanohydroxyapatite for Osteochondral Tissue Engineering

    Directory of Open Access Journals (Sweden)

    K. T. Shalumon

    2016-12-01

    confirmed cell proliferation and tissue development from gross view and SEM observation. IF staining of OCN and COL II in the bone and cartilage parts of OC scaffolds and tissue-specific histological analysis exhibited a time-dependent tissue re-modeling and confirmed the potential application of the biphasic scaffold in osteochondral tissue engineering.

  6. Decellularized cartilage may be a chondroinductive material for osteochondral tissue engineering.

    Directory of Open Access Journals (Sweden)

    Amanda J Sutherland

    Full Text Available Extracellular matrix (ECM-based materials are attractive for regenerative medicine in their ability to potentially aid in stem cell recruitment, infiltration, and differentiation without added biological factors. In musculoskeletal tissue engineering, demineralized bone matrix is widely used, but recently cartilage matrix has been attracting attention as a potentially chondroinductive material. The aim of this study was thus to establish a chemical decellularization method for use with articular cartilage to quantify removal of cells and analyze the cartilage biochemical content at various stages during the decellularization process, which included a physically devitalization step. To study the cellular response to the cartilage matrix, rat bone marrow-derived mesenchymal stem cells (rBMSCs were cultured in cell pellets containing cells only (control, chondrogenic differentiation medium (TGF-β, chemically decellularized cartilage particles (DCC, or physically devitalized cartilage particles (DVC. The chemical decellularization process removed the vast majority of DNA and about half of the glycosaminoglycans (GAG within the matrix, but had no significant effect on the amount of hydroxyproline. Most notably, the DCC group significantly outperformed TGF-β in chondroinduction of rBMSCs, with collagen II gene expression an order of magnitude or more higher. While DVC did not exhibit a chondrogenic response to the extent that DCC did, DVC had a greater down regulation of collagen I, collagen X and Runx2. A new protocol has been introduced for cartilage devitalization and decellularization in the current study, with evidence of chondroinductivity. Such bioactivity along with providing the 'raw material' building blocks of regenerating cartilage may suggest a promising role for DCC in biomaterials that rely on recruiting endogenous cell recruitment and differentiation for cartilage regeneration.

  7. Bilayered chitosan-based scaffolds for osteochondral tissue engineering: influence of hydroxyapatite on in vitro cytotoxicity and dynamic bioactivity studies in a specific double-chamber bioreactor.

    Science.gov (United States)

    Malafaya, Patrícia B; Reis, Rui L

    2009-02-01

    Osteochondral tissue engineering presents a current research challenge due to the necessity of combining both bone and cartilage tissue engineering principles. In the present study, bilayered chitosan-based scaffolds are developed based on the optimization of both polymeric and composite scaffolds. A particle aggregation methodology is proposed in order to achieve an improved integrative bone-cartilage interface needed for this application, since any discontinuity is likely to cause long-term device failure. Cytotoxicity was evaluated by the MTS assay with the L929 fibroblast cell line for different conditions. Surprisingly, in composite scaffolds using unsintered hydroxyapatite, cytotoxicity was observed in vitro. This work reports the investigation that was conducted to overcome and explain this behaviour. It is suggest that the uptake of divalent cations may induce the cytotoxic behaviour. Sintered hydroxyapatite was consequently used and showed no cytotoxicity when compared to the controls. Microcomputed tomography (micro-CT) was carried out to accurately quantify porosity, interconnectivity, ceramic content, particle and pore sizes. The results showed that the developed scaffolds are highly interconnected and present the ideal pore size range to be morphometrically suitable for the proposed applications. Dynamical mechanical analysis (DMA) demonstrated that the scaffolds are mechanically stable in the wet state even under dynamic compression. The obtained elastic modulus was, respectively, 4.21+/-1.04, 7.98+/-1.77 and 6.26+/-1.04 MPa at 1 Hz frequency for polymeric, composite and bilayered scaffolds. Bioactivity studies using both a simulated body fluid (SBF) and a simulated synovial fluid (SSF) were conducted in order to assure that the polymeric component for chondrogenic part would not mineralize, as confirmed by scanning electron microscopy (SEM), inductively coupled plasma-optical emission spectroscopy (ICP) and energy-dispersive spectroscopy (EDS) for

  8. Custom Design of the Cardiac Microenvironment With Biomaterials

    Science.gov (United States)

    Davis, Michael E.; Hsieh, Patrick C.H.; Grodzinsky, Alan J.; Lee, Richard T.

    2009-01-01

    Many strategies for repairing injured myocardium are under active investigation, with some early encouraging results. These strategies include cell therapies, despite little evidence of long-term survival of exogenous cells, and gene or protein therapies, often with incomplete control of locally-delivered dose of the factor. We propose that, ultimately, successful repair and regeneration strategies will require quantitative control of the myocardial microenvironment. This precision control can be engineered through designed biomaterials that provide quantitative adhesion, growth, or migration signals. Quantitative timed release of factors can be regulated by chemical design to direct cellular differentiation pathways such as angiogenesis and vascular maturation. Smart biomaterials respond to the local environment, such as protease activity or mechanical forces, with controlled release or activation. Most of these new biomaterials provide much greater flexibility for regenerating tissues ex vivo, but emerging technologies like self-assembling nanofibers can now establish intramyocardial cellular microenvironments by injection. This may allow percutaneous cardiac regeneration and repair approaches, or injectable-tissue engineering. Finally, materials can be made to multifunction by providing sequential signals with custom design of differential release kinetics for individual factors. Thus, new rationally-designed biomaterials no longer simply coexist with tissues, but can provide precision bioactive control of the microenvironment that may be required for cardiac regeneration and repair. PMID:16002755

  9. Osteochondritis Dissecans (OCD)

    Science.gov (United States)

    ... or swimming instead as a means of physical therapy.Can osteochondritis dissecans be cured?Young people have the best chance of returning to their usual activity levels, although they might not be able to keep playing sports with repetitive motions, such as pitching in baseball. ...

  10. Bioinspired scaffolds for osteochondral regeneration.

    Science.gov (United States)

    Lopa, Silvia; Madry, Henning

    2014-08-01

    Osteochondral defects are difficult to treat because the articular cartilage and the subchondral bone have dissimilar characteristics and abilities to regenerate. Bioinspired scaffolds are designed to mimic structural and biological cues of the native osteochondral unit, supporting both cartilaginous and subchondral bone repair and the integration of the newly formed osteochondral matrix with the surrounding tissues. The aim of this review is to outline fundamental requirements and strategies for the development of biomimetic scaffolds reproducing the unique and multifaceted anatomical structure of the osteochondral unit. Recent progress in preclinical animal studies using bilayer and multilayer scaffolds, together with continuous gradient scaffolds will be discussed and placed in a translational perspective with data emerging from their clinical application to treat osteochondral defects in patients.

  11. Bioprinting of a mechanically enhanced three-dimensional dual cell-laden construct for osteochondral tissue engineering using a multi-head tissue/organ building system

    Science.gov (United States)

    Shim, Jin-Hyung; Lee, Jung-Seob; Kim, Jong Young; Cho, Dong-Woo

    2012-08-01

    The aim of this study was to build a mechanically enhanced three-dimensional (3D) bioprinted construct containing two different cell types for osteochondral tissue regeneration. Recently, the production of 3D cell-laden structures using various scaffold-free cell printing technologies has opened up new possibilities. However, ideal 3D complex tissues or organs have not yet been printed because gel-state hydrogels have been used as the principal material and are unable to maintain the desired 3D structure due to their poor mechanical strength. In this study, thermoplastic biomaterial polycaprolactone (PCL), which shows relatively high mechanical properties as compared with hydrogel, was used as a framework for enhancing the mechanical stability of the bioprinted construct. Two different alginate solutions were then infused into the previously prepared framework consisting of PCL to create the 3D construct for osteochondral printing. For this work, a multi-head tissue/organ building system (MtoBS), which was particularly designed to dispense thermoplastic biomaterial and hydrogel having completely different rheology properties, was newly developed and used to bioprint osteochondral tissue. It was confirmed that the line width, position and volume control of PCL and alginate solutions were adjustable in the MtoBS. Most importantly, dual cell-laden 3D constructs consisting of osteoblasts and chondrocytes were successfully fabricated. Further, the separately dispensed osteoblasts and chondrocytes not only retained their initial position and viability, but also proliferated up to 7 days after being dispensed.

  12. Biomechanics and mechanobiology in osteochondral tissues.

    Science.gov (United States)

    McMahon, L A; O'Brien, F J; Prendergast, P J

    2008-09-01

    Osteochondral tissues are those that form the synovial joints, namely cartilage and bone, including sub-chondral bone. The biomechanical purpose of synovial joints is to provide lubricated contact between the moving surfaces with as little frictional forces as possible. This is achieved by separating the cartilage layers by a thin film of fluid and supporting the cartilage layers by a bony trabecular network that becomes dense and more calcified immediately underneath the cartilage layer. Each tissue's biomechanical behavior is well understood after several decades of research and this behavior is briefly reviewed here, as are the concepts relating to the mechanical induction of cartilage degradation (osteoarthritis) with a discussion of clinical strategies for repair. Focusing on tissue-engineering strategies, the following concepts are reviewed: scaffolds, bioreactors and computational simulations, with an analysis of how these elements may be combined in future.

  13. Osteochondral lesion of the tibial plafond treated with a retrograde osteochondral autograft: a report of two cases

    Directory of Open Access Journals (Sweden)

    Kensuke Okamura

    2017-04-01

    Conclusion: Use of the retrograde osteochondral autograft produced satisfactory results including the return to sports. The retrograde osteochondral autograft can be considered recommendable for treating OLTPs.

  14. REALIZATION OF A CUSTOM DESIGNED FPGA BASED EMBEDDED CONTROLLER.

    Energy Technology Data Exchange (ETDEWEB)

    SEVERINO,F.; HARVEY, M.; HAYES, T.; HOFF, L.; ODDO, P.; SMITH, K.S.

    2007-10-15

    As part of the Low Level RF (LLRF) upgrade project at Brookhaven National Laboratory's Collider-Accelerator Department (BNL C-AD), we have recently developed and tested a prototype high performance embedded controller. This controller is a custom designed PMC module employing a Xilinx V4FX60 FPGA with a PowerPC405 embedded processor, and a wide variety of on board peripherals (DDR2 SDRAM, FLASH, Ethernet, PCI, multi-gigabit serial transceivers, etc.). The controller is capable of running either an embedded version of LINUX or VxWorks, the standard operating system for RHIC front end computers (FECs). We have successfully demonstrated functionality of this controller as a standard RHIC FEC and tested all on board peripherals. We now have the ability to develop complex, custom digital controllers within the framework of the standard RHIC control system infrastructure. This paper will describe various aspects of this development effort, including the basic hardware, functional capabilities, the development environment, kernel and system integration, and plans for further development.

  15. 3D printing of novel osteochondral scaffolds with graded microstructure

    Science.gov (United States)

    Nowicki, Margaret A.; Castro, Nathan J.; Plesniak, Michael W.; Zhang, Lijie Grace

    2016-10-01

    Osteochondral tissue has a complex graded structure where biological, physiological, and mechanical properties vary significantly over the full thickness spanning from the subchondral bone region beneath the joint surface to the hyaline cartilage region at the joint surface. This presents a significant challenge for tissue-engineered structures addressing osteochondral defects. Fused deposition modeling (FDM) 3D bioprinters present a unique solution to this problem. The objective of this study is to use FDM-based 3D bioprinting and nanocrystalline hydroxyapatite for improved bone marrow human mesenchymal stem cell (hMSC) adhesion, growth, and osteochondral differentiation. FDM printing parameters can be tuned through computer aided design and computer numerical control software to manipulate scaffold geometries in ways that are beneficial to mechanical performance without hindering cellular behavior. Additionally, the ability to fine-tune 3D printed scaffolds increases further through our investment casting procedure which facilitates the inclusion of nanoparticles with biochemical factors to further elicit desired hMSC differentiation. For this study, FDM was used to print investment-casting molds innovatively designed with varied pore distribution over the full thickness of the scaffold. The mechanical and biological impacts of the varied pore distributions were compared and evaluated to determine the benefits of this physical manipulation. The results indicate that both mechanical properties and cell performance improve in the graded pore structures when compared to homogeneously distributed porous and non-porous structures. Differentiation results indicated successful osteogenic and chondrogenic manipulation in engineered scaffolds.

  16. Treatment of osteochondral defects of the talus

    NARCIS (Netherlands)

    van Bergen, C. J. A.; de Leeuw, P. A. J.; van Dijk, C. N.

    2008-01-01

    This review article provides a current concepts overview of osteochondral defects of the talus, with special emphasis on treatment options, their indications and future developments. Osteochondral defects of the talar dome are mostly caused by a traumatic event. They may lead to deep ankle pain on

  17. Integrating biologically inspired nanomaterials and table-top stereolithography for 3D printed biomimetic osteochondral scaffolds

    Science.gov (United States)

    Castro, Nathan J.; O'Brien, Joseph; Zhang, Lijie Grace

    2015-08-01

    The osteochondral interface of an arthritic joint is notoriously difficult to regenerate due to its extremely poor regenerative capacity and complex stratified architecture. Native osteochondral tissue extracellular matrix is composed of numerous nanoscale organic and inorganic constituents. Although various tissue engineering strategies exist in addressing osteochondral defects, limitations persist with regards to tissue scaffolding which exhibit biomimetic cues at the nano to micro scale. In an effort to address this, the current work focused on 3D printing biomimetic nanocomposite scaffolds for improved osteochondral tissue regeneration. For this purpose, two biologically-inspired nanomaterials have been synthesized consisting of (1) osteoconductive nanocrystalline hydroxyapatite (nHA) (primary inorganic component of bone) and (2) core-shell poly(lactic-co-glycolic) acid (PLGA) nanospheres encapsulated with chondrogenic transforming growth-factor β1 (TGF-β1) for sustained delivery. Then, a novel table-top stereolithography 3D printer and the nano-ink (i.e., nHA + nanosphere + hydrogel) were employed to fabricate a porous and highly interconnected osteochondral scaffold with hierarchical nano-to-micro structure and spatiotemporal bioactive factor gradients. Our results showed that human bone marrow-derived mesenchymal stem cell adhesion, proliferation, and osteochondral differentiation were greatly improved in the biomimetic graded 3D printed osteochondral construct in vitro. The current work served to illustrate the efficacy of the nano-ink and current 3D printing technology for efficient fabrication of a novel nanocomposite hydrogel scaffold. In addition, tissue-specific growth factors illustrated a synergistic effect leading to increased cell adhesion and directed stem cell differentiation.

  18. Recent Advances in Egypt for Treatment of Talar Osteochondral Lesions.

    Science.gov (United States)

    Haleem, Amgad M; AbouSayed, Mostafa M; Gomaa, Mohammed

    2016-06-01

    Treatment of osteochondral defects (OCLs) of the talus is a challenging orthopedic surgery. Treatment of talar OCLs has evolved through the 3 "R" paradigm: reconstruction, repair, and replacement. This article highlights current state-of-the-art techniques and reviews recent advances in the literature about articular cartilage repair using various novel tissue engineering approaches, including various scaffolds, growth factors, and cell niches; which include chondrocytes and culture-expanded bone marrow-derived mesenchymal stem cells. Copyright © 2016 Elsevier Inc. All rights reserved.

  19. Osteochondral Interface Stiffening in Mandibular Condylar Osteoarthritis.

    Science.gov (United States)

    Zhang, J; Liao, L; Zhu, J; Wan, X; Xie, M; Zhang, H; Zhang, M; Lu, L; Yang, H; Jing, D; Liu, X; Yu, S; Lu, X L; Chen, C; Shan, Z; Wang, M

    2017-12-01

    Osteoarthritis (OA) of the temporomandibular joint (TMJ) is associated with dental biomechanics. A major change during OA progression is the ossification of the osteochondral interface. This study investigated the formation, radiological detectability, and mechanical property of the osteochondral interface at an early stage, the pathogenesis significance of which in OA progression is of clinical interest and remains elusive for the TMJ. Unilateral anterior crossbite (UAC) was performed on 6-wk-old rats as we previously reported. TMJs were harvested at 4, 12, and 20 wk. The progression of TMJ OA was evaluated using a modified Osteoarthritis Research Society International (OARSI) score system. Osteochondral interface was investigated by quantifying the thickness via von Kossa staining of histological slices and in vivo calcium deposition by calcein injection. Tissue ossification was imaged by micro-computed tomography (CT). Mechanical properties were measured at nanoscale using dynamic indentation. Time-dependent TMJ cartilage lesions were elicited by UAC treatment. Geometric change of the condyle head and increased value of the OARSI score were evident in UAC TMJs. At the osteochondral interface, there was not only enhanced deep-zone cartilage calcification but also calcium deposition at the osseous boundary. The thickness, density, and stiffness of the osteochondral interface were all significantly increased. The enhanced ossification of the osteochondral interface is a joint outcome of the aberrant deeper cartilage calcification at the superior region and promoted formation of subchondral cortical bone at the inferior region. The micro-CT detectable ossification from an early stage thus is of diagnostic significance. Although the environment of the cartilage and subchondral bone could be changed due to the stiffness of the interface, whether or not the stiffened interface would accelerate OA progress remains to be confirmed. With that evidence, the osteochondral

  20. Driving a car with custom-designed fuzzy inferencing VLSI chips and boards

    Science.gov (United States)

    Pin, Francois G.; Watanabe, Yutaka

    1993-01-01

    Vehicle control in a-priori unknown, unpredictable, and dynamic environments requires many calculational and reasoning schemes to operate on the basis of very imprecise, incomplete, or unreliable data. For such systems, in which all the uncertainties can not be engineered away, approximate reasoning may provide an alternative to the complexity and computational requirements of conventional uncertainty analysis and propagation techniques. Two types of computer boards including custom-designed VLSI chips were developed to add a fuzzy inferencing capability to real-time control systems. All inferencing rules on a chip are processed in parallel, allowing execution of the entire rule base in about 30 microseconds, and therefore, making control of 'reflex-type' of motions envisionable. The use of these boards and the approach using superposition of elemental sensor-based behaviors for the development of qualitative reasoning schemes emulating human-like navigation in a-priori unknown environments are first discussed. Then how the human-like navigation scheme implemented on one of the qualitative inferencing boards was installed on a test-bed platform to investigate two control modes for driving a car in a-priori unknown environments on the basis of sparse and imprecise sensor data is described. In the first mode, the car navigates fully autonomously, while in the second mode, the system acts as a driver's aid providing the driver with linguistic (fuzzy) commands to turn left or right and speed up or slow down depending on the obstacles perceived by the sensors. Experiments with both modes of control are described in which the system uses only three acoustic range (sonar) sensor channels to perceive the environment. Simulation results as well as indoors and outdoors experiments are presented and discussed to illustrate the feasibility and robustness of autonomous navigation and/or safety enhancing driver's aid using the new fuzzy inferencing hardware system and some human

  1. Arthroscopic osteochondral autologous transplantation for the treatment of osteochondritis dissecans of the femoral head

    Directory of Open Access Journals (Sweden)

    Uchida Soshi

    2017-01-01

    Full Text Available Osteochondritis dissecans (OCD of the femoral head is an unusual cause of hip pain. It can be associated with other intra-articular pathologies including: acetabular labral tears or bone deformities such as Legg-Calve-Perthes Disease (LCPD. In this article, we propose a modern surgical technique using an arthroscopic antegrade and retrograde osteochondral autologous transplantation (OAT procedure for assessing and treating OCD lesions of the femoral head.

  2. Osteochondritis Dissecans of the Hip

    Energy Technology Data Exchange (ETDEWEB)

    Linden, B. [Hoeglands Hospital, Eksjoe (Sweden). Dept. of Orthopedic Surgery; Jonsson, K. [Univ. Hospital, Lund (Sweden). Center for Medical Imaging and Physiology; Redlund-Johnell, I. [Univ. Hospital, Malmoe (Sweden). Dept. of Diagnostic Radiology

    2003-03-01

    Purpose: To investigate the clinical and radiological characteristics of osteochondritis dissecans (OD) of the hip and the outcome of this condition after treatment. Material and Methods: Twelve male and 3 female patients with OD were retrospectively studied. Six patients had a history of Legg-Calve-Perthes disease (LCPD) and among them 2 also had had a trauma to the hip. A further 5 had had trauma and 1 a developmental dislocation of the hip (DDH). The remaining 3 patients had no history of previous hip disease or trauma. All patients were examined with plain radiography, 7 with MR, 3 with CT and 2 with hip arthrography. Results: All OD lesions were detected at plain radiography, and most of them were located near the fovea. At MR the lesions had low signal intensity at T1-weighted sequences, and 6/7 had edema or fluid collection in or adjacent to the lesion on T2-weighted sequences. The early treatment in 7 patients was surgery, 2 had had conservative treatment and 6 no treatment. At follow-up 12 years after radiological diagnosis, 5 patients had hip arthrosis, 4 of whom were treated with arthroplasty. All but 3 had reduced hip rotation and all but 2 (with arthroplasty) had load pain. Three of the patients with earlier surgery had not developed arthrosis. Conclusions: OD lesions are usually well seen with plain radiography. There is a great risk of developing early arthrosis and it seems that early surgery is connected with arthrosis development. Thus only symptomatic treatment is recommended.

  3. The Effects of a Custom-Designed Animation Program on Learning Chinese Characters

    Science.gov (United States)

    Shi, Lin

    2012-01-01

    The purpose of this study is to evaluate the effects of a custom-designed computer animation program on learning Chinese characters by beginning learners of Chinese as Foreign Language (CFL) in a higher education setting. This study used a matched comparison quasi-experimental design to explore the effects of the customized computer program within…

  4. Osteochondral talar lesions and ankle biomechanics

    NARCIS (Netherlands)

    Zengerink, M.

    2017-01-01

    An osteochondral defect (OCD) of the talus involves the articular cartilage and subchondral bone. Patients are often young, active people with deep ankle pain during weightbearing. Trauma, like an ankle sprain, is the most frequent etiologic factor. Most talar OCDs are treated by means of

  5. Chitosan-Based Bilayer Hydroxyapatite Nanorod Composite Scaffolds for Osteochondral Regeneration

    Science.gov (United States)

    Swanson, Shawn

    Osteochondral defects involve injury to bone and cartilage. As articular cartilage is worn down, bone in the joint begins to rub together, causing bone spurs. This is known as osteoarthritis, and is a common issue among the aging population. This problem presents an interesting opportunity for tissue engineering. Tissue engineering is an approach to treatment of tissue defects where synthetic, three dimensional (3-D) scaffolds are implanted in a defect to facilitate healing. The osteochondral scaffold consists of two regions in the form of a bilayer scaffold- one to mimic bone with osteoconductive properties, and one to mimic cartilage with biomimetic properties. One approach to improving the osteoconductivity of tissue engineering scaffolds is the addition of hydroxyapatite (HAp), the main mineral phase in bone. HAp with nanorod morphology is desirable because it is biomimetic for the calcium phosphate found in bone. Incorporating HAp nanorods in bone tissue engineering scaffolds to form a composite material may increase scaffold osteoconductivity. The cartilage scaffold is fabricated from chitosan and hyaluronic acid (HA). HA is a known component of cartilage and thus is biomimetic. The bilayer scaffolds were seeded with osteoblast-like MG-63 cells to investigate cell migration and were evaluated with Alamar Blue proliferation assay. The cells successfully migrated to the bone region of the scaffold, indicating that the bilayer scaffold provides a promising osteochondral scaffold.

  6. [Limited osteochondritis complicating coxa valga in children (author's transl)].

    Science.gov (United States)

    Pouliquen, J C; Rigault, P; Guyonvarch, G; Le Luhant, M

    1981-01-01

    Height cases of limited "osteochondritis" were observed in children showing some degree of coxa valga. The radiological appearances were different from those of Perthe's disease and resembled those of osteochondritis dissecans of the knee but with stability during their development. These "osteochondritis" were often bilateral; all the patients were male. In four cases some degree of platyspindyly was seen. It is thought that these hips are earlier and limited varieties of osteo-chondrodysplasia. The indications for varus osteotomy are discussed.

  7. Noncontact detection of dry eye using a custom designed IR thermal image system

    Science.gov (United States)

    Su, Tai Yuan; Chen, Kerh Hwa; Liu, Po Hsuan; Wu, Ming Hong; Chang, David O.; Chiang, Huihua

    2011-03-01

    Dry eye syndrome is a common irritating eye disease. Current clinical diagnostic methods are invasive and uncomfortable to patients. A custom designed noncontact infrared (IR) thermal image system was developed to measure the spatial and temporal variation of the ocular surface temperature over a 6-second eye-opening period. We defined two parameters: the temperature difference value and the compactness value to represent the degree of the temperature change and irregularity of the temperature distribution on the tear film. By using these two parameters, in this study, a linear discrimination result for the dry eye and the normal eye groups; the sensitivity is 0.9, the specificity is 0.86 and the receiver operating characteristic (ROC) area is 0.91. The result suggests that the custom designed IR thermal image system may be used as an effective tool for noncontact detection of dry eye.

  8. Endovascular Repair of Ascending Aortic Pseudoaneurysm With Custom-Designed Endograft.

    Science.gov (United States)

    Piffaretti, Gabriele; Cottini, Marzia; Carrafiello, Gianpaolo; Castelli, Patrizio; Beghi, Cesare; Mariscalco, Giovanni

    2015-08-01

    Open repair of ascending aortic pseudoaneurysm (AscAP) carries high risks and mortality rate. Previous papers reported the off-label use of standard thoracic or abdominal endograft in very selected cases. We present the case of a 57-year-old man with an AscAP successfully managed with a new custom-designed endograft. Copyright © 2015 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

  9. Osteochondritis of the Distal Tibial Epiphysis

    Directory of Open Access Journals (Sweden)

    Firass EL Hajj

    2012-01-01

    Full Text Available Osteochondritis of the distal tibial epiphysis is a very rare entity. 9 cases have been described in 7 articles and 8 other cases have been mentioned in textbooks. This paper describes the 10th case of osteochondritis of the distal tibial epiphysis and summarizes the clinical and radiological presentations of the 9 other cases. The etiology of this entity is well debated in the literature. We believe that it results from a vascular abnormality in the distal tibial epiphysis associated with a mechanical stress (trauma, excessive overload, etc.. Since it is a self-limited disease, the prognosis is good and the younger the patient is the better the prognosis will be. In general, this entity responds well to conservative treatment.

  10. Osteochondritis Dissecans Of The Knee Joint (Osgood-Schlatters ...

    African Journals Online (AJOL)

    Both knee joint were X-rayed and the radiographs revealed bilateral Osteochondritis dissecans of the knee joints (Osgood schlatters disease). This case is being reported to highlight on the epidemiology, etiology clinical appearance, possibilities for radiological diagnoses, classification of osteochondritis dissecans, the ...

  11. Prevalence of osteochondral fragments, osteochondrosis dissecans and palmar/plantar osteochondral fragments in Hanoverian Warmblood horses.

    Science.gov (United States)

    Hilla, Dorothea; Distl, Ottmar

    2013-01-01

    In this study, the prevalences of osteochondral fragments in the distal (DUI) and proximal interphalangeal joints (PIJ) as well as in the fetlock, hock and stifle joints, of palmar/plantar osteochondral fragments in the fetlock joints (POFs) and of osteochondrosis dissecans (OCD) in fetlock, hock and stifle joints were estimated in a large sample of Hanoverian Warmblood horses. For this purpose, radiographic findings of 9478 Hanoverian Warmblood horses collected from 2005 to 2011 were analyzed. Overall 31.9% of the horses showed one or more osteochondral fragments in at least one joint. The fetlocks were predominantly affected with a prevalence of 19.7%, followed by the hocks with 8.2% and the stifles with 2.7%. For OCD, an overall prevalence of 14.3% was determined. In fetlock joints, 5.4% of the horses had OCD, in the hock joints 6.9% and in the stifle joints 2.6%, with bilateral occurrence in 25.8% of the hock, 24.9% of the stifle and 12.6% of the fetlock joints. POFs were observed in 6.8% of the horses. With a prevalence of 6.3%, the hindlimbs were significantly more frequently affected than the forelimbs with 0.6%. Of the horses with POFs, 16.5% were also affected with OCD. The high prevalences for osteochondral fragments determined in this study show their great importance with regard to economics and animal welfare.

  12. A comparative study on collagen type I and hyaluronic acid dependent cell behavior for osteochondral tissue bioprinting.

    Science.gov (United States)

    Park, Ju Young; Choi, Jong-Cheol; Shim, Jin-Hyung; Lee, Jung-Seob; Park, Hyoungjun; Kim, Sung Won; Doh, Junsang; Cho, Dong-Woo

    2014-09-01

    Bioprinting is a promising technique for engineering composite tissues, such as osteochondral tissues. In this study, as a first step toward bioprinting-based osteochondral tissue regeneration, we systematically examined the behavior of chondrocytes and osteoblasts to hyaluronic acid (HA) and type I collagen (Col-1) hydrogels. First, we demonstrated that cells on hydrogels that were comprised of major native tissue extracellular matrix (ECM) components (i.e. chondrocytes on HA hydrogels and osteoblasts on Col-1 hydrogels) exhibited better proliferation and cell function than cells on non-native ECM hydrogels (i.e., chondrocytes on Col-1 hydrogels and osteoblasts on HA hydrogels). In addition, cells located near their native ECM hydrogels migrated towards them. Finally, we bioprinted three-dimensional (3D) osteochondral tissue-mimetic structures composed of two compartments, osteoblast-encapsulated Col-1 hydrogels and chondrocyte-encapsulated HA hydrogels, and found viability and functions of each cell type were well maintained within the 3D structures up to 14 days in vitro. These results suggest that with proper choice of hydrogel materials, bioprinting-based approaches can be successfully applied for osteochondral tissue regeneration.

  13. Osteochondral Autograft Plug Transfer for Treatment of Osteochondritis Dissecans of the Capitellum in Adolescent Athletes

    OpenAIRE

    Lyons, Matthew Lawrence; Hart, Joseph M.; Freilich, Aaron M.; Dacus, Angelo R.; Diduch, David R.; Chhabra, Abhinav Bobby

    2014-01-01

    Objectives: Osteochondritis dissecans (OCD) of the capitellum is a condition most commonly seen in adolescents involved in repetitive over-head sports and can profoundly affect both ability to return to play and long-term elbow function. Large, unstable defects, defined as those greater than 1 cm in size, have unproven or poor long term outcomes with surgical interventions such as fragment excision, microfracture or attempted fixation. Treatment of similarly sized OCD lesions in the knee with...

  14. Autonomous navigation of a mobile robot using custom-designed qualitative reasoning VLSI chips and boards

    Energy Technology Data Exchange (ETDEWEB)

    Pin, F.G.; Pattay, R.S. (Oak Ridge National Lab., TN (United States)); Watanabe, H.; Symon, J. (North Carolina Univ., Chapel Hill, NC (United States). Dept. of Computer Science)

    1991-01-01

    Two types of computer boards including custom-designed VLSI chips have been developed to add a qualitative reasoning capability to the real-time control of autonomous mobile robots. The design and operation of these boards are first described and an example of their use for the autonomous navigation of a mobile robot is presented. The development of qualitative reasoning schemes emulating human-like navigation is a-priori unknown environments is discussed. The efficiency of such schemes, which can consist of as little as a dozen qualitative rules, is illustrated in experiments involving an autonomous mobile robot navigating on the basis of very sparse inaccurate sensor data. 17 refs., 6 figs.

  15. Using custom-designed VLSI fuzzy inferencing chips for the autonomous navigation of a mobile robot

    Energy Technology Data Exchange (ETDEWEB)

    Pin, F.G.; Pattay, R.S. (Oak Ridge National Lab., TN (United States)); Watanabe, Hiroyuki; Symon, J. (North Carolina Univ., Chapel Hill, NC (United States). Dept. of Computer Science)

    1991-01-01

    Two types of computer boards including custom-designed VLSI fuzzy inferencing chips have been developed to add a qualitative reasoning capability to the real-time control of autonomous mobile robots. The design and operation of these boards are first described and an example of their use for the autonomous navigation of mobile robot is presented. The development of qualitative reasoning schemes emulating human-like navigation in apriori unknown environments is discussed. An approach using superposition of elemental sensor-based behaviors is shown to alloy easy development and testing of the inferencing rule base, while providing for progressive addition of behaviors to resolve situations of increasing complexity. The efficiency of such schemes, which can consist of as little as a dozen qualitative rules, is illustrated in experiments involving an autonomous mobile robot navigating on the basis of very sparse and inaccurate sensor data. 17 refs., 6 figs.

  16. Novel nanostructured scaffold for osteochondral regeneration: pilot study in horses.

    Science.gov (United States)

    Kon, E; Mutini, A; Arcangeli, E; Delcogliano, M; Filardo, G; Nicoli Aldini, N; Pressato, D; Quarto, R; Zaffagnini, S; Marcacci, M

    2010-06-01

    The present in vivo preliminary experiment is aimed at testing mechanical and biological behaviour of a new nano-structured composite multilayer biomimetic scaffold for the treatment of chondral and osteochondral defects. The three-dimensional biomimetic scaffold (Fin-Ceramica Faenza S.p.A., Faenza-Italy) was obtained by nucleating collagen fibrils with hydroxyapatite nanoparticles, in two configurations, bi- and tri-layered, to reproduce, respectively, chondral and osteochondral anatomy. Chondral defects (lateral condyle) and deep osteochondral defects (medial condyle) were made in the distal epiphysis of the third metacarpal bone of both forelimbs of two adult horses and treated respectively with the chondral and osteochondral grafts. Both animals were euthanised six months follow up. The images obtained at the second look arthroscopy evaluation, performed two months after surgery, demonstrated good filling of the chondral and osteo-chondral defects without any inflammatory reaction around and inside the lesions. At the histological analysis the growth of trabecular bone in the osteochondral lesion was evident. Only in one case, the whole thickness of the osteochondral lesion was filled by fibrocartilaginous tissue. The formation of a tidemark line was evident at the interface with the newly formed bone. Newly formed fibrocartilaginous tissue was present in the area of the chondral defect. Initial alignment of the collagen fibres was recognisable with polarised light in both groups. The results of the present pilot study showed that this novel osteochondral and chondral scaffold may act as a suitable matrix to facilitate orderly regeneration of bone and hyaline-like cartilage. Copyright 2010 John Wiley & Sons, Ltd.

  17. Comparison of fresh osteochondral autografts and allografts: a canine model.

    Science.gov (United States)

    Glenn, R Edward; McCarty, Eric C; Potter, Hollis G; Juliao, Saul F; Gordon, Jeffrey D; Spindler, Kurt P

    2006-07-01

    Osteochondral autografts and allografts have been widely used in the treatment of isolated grade IV articular cartilage lesions of the knee. However, the authors are not aware of any study that has prospectively compared fresh osteochondral autografts to fresh allografts with regard to imaging, biomechanical testing, and histology. The imaging, biomechanical properties, and histologic appearance of fresh osteochondral autograft and fresh allograft are similar with respect to bony incorporation into host bone, articular cartilage composition, and biomechanical properties. Controlled laboratory study. Eighteen adult dogs underwent bilateral knee osteochondral graft implantation after creation of an Outerbridge grade IV cartilage defect. One knee received an autograft, and the contralateral knee received a fresh allograft. Nine dogs were sacrificed at 3 months, and 9 dogs were sacrificed at 6 months. Graft analysis included gross examination, radiographs, magnetic resonance imaging, biomechanical testing, and histology. Magnetic resonance imaging demonstrated excellent bony incorporation of both autografts and allografts. Biomechanical testing demonstrated no significant difference between autografts versus allografts versus control at 3 or 6 months (P = .36-.91). A post hoc calculation showed 80% power to detect a 30% difference between allograft and control. Histologic examination showed normal cartilage structure for both autografts and allografts. Fresh osteochondral autograft and fresh allograft tissues are not statistically different with respect to bony incorporation, articular cartilage composition, or biomechanical properties up to 6 months after implantation. The use of fresh allograft tissue to treat osteochondral defects eliminates morbidity associated with harvesting autograft tissue without compromising the results of the surgical procedure.

  18. Late repair of an osteochondral fracture of the patella.

    Science.gov (United States)

    Hoshino, C Max; Thomas, Bradley M

    2010-04-01

    Acute patellar dislocations are a common injury in young patients. Osteochondral fractures are commonly associated with this injury, frequently necessitating surgical treatment. This article presents a case of a 23-year-old woman who sustained a large osteochondral fracture of the medial facet of the patella during a first-time acute patellar dislocation. The patient was lost to follow-up; consequently, surgical treatment was not performed until 8 weeks after injury. Diagnostic arthroscopy demonstrated a large osteochondral fragment in the suprapatellar pouch and a defect on the medial facet of the patella with early fibrocartilage growth. Using an open approach, the osteochondral fracture was fixed with headless screws buried beneath the cartilage. After fracture fixation, continued lateral subluxation of the patella was present; therefore, to improve patellar tracking and protect our fracture fixation, a Fulkerson tibial tubercle osteotomy (including a lateral release) and a medial patellofemoral ligament repair were performed. At the conclusion of the surgery, we had achieved rigid fixation of the fracture and normalized patellofemoral tracking.At 1 year post-injury, the patient has achieved union of her patellar osteochondral fracture and tibial tubercle osteotomy. She has full range of motion and minimal anterior knee pain and has not experienced further episodes of patellar instability. Even in patients who present in a delayed fashion, consideration should be given to the repair of patellar osteochondral fractures and, if necessary, realignment of the extensor mechanism. Copyright 2010, SLACK Incorporated.

  19. Isolated osteochondral fracture of the patella without patellar dislocation.

    Science.gov (United States)

    Bhatt, Jay; Montalban, Antonio Santa Cruz; Wang, Kook Hyun; Lee, Hee Du; Nha, Kyung Wook

    2011-01-03

    Chondral fractures of the patella are associated with acute dislocation of the patella. Osteochondral fracture in patellar dislocation is located in the medial facet of the patella. This article presents a case of a 15-year-old female ballerina with isolated displaced osteochondral fracture of the patella without patellar dislocation. She had no history of trauma. A Merchant's view of both knees showed mild subluxation of the patella, a small fragment on the lateral aspect of the knee, and a small defect of the centromedial patella. Axial magnetic resonance imaging (MRI) revealed an osteochondral fragment measuring 13 mm medial to the patella. However, the medial patellofemoral ligament and medial retinaculum were intact. An effusion on the medial side of the patella consistent with hemarthrosis was observed. An absence of a contusion or bone bruise on the lateral femoral condyle was shown. The loose body was removed arthroscopically. Intraoperative findings included a 1.5×2 cm osteochondral fragment. It is unusual that the osteochondral patellar defect site in this patient was in the inferior and central areas of the patella. Patellar chondral fractures without dislocation or patella fracture are rare. Therefore, the possibility of a trivial trauma leading to an osteochondral fracture should be kept in mind in adolescent and young adults who present with knee pain and hemarthrosis. Copyright 2011, SLACK Incorporated.

  20. Osteochondral Allograft Transplantation for Femoral Trochlear Dysplasia

    Science.gov (United States)

    Vansadia, Dharmpal V.; Heltsley, James R.; Montgomery, Scott; Suri, Misty; Jones, Deryk G.

    2016-01-01

    Background: The risk factors for patellofemoral joint instability include laxity of medial patellar restraints, abnormal limb geometry, femoral and tibial malrotation, patella alta, and trochlear dysplasia. Femoral trochlear dysplasia is characterized by a hypoplastic or shallow trochlear groove. Case Report: We report the case of a 31-year-old female with trochlear dysplasia and recurrent patella dislocations, laxity of the medial patellofemoral ligament (MPFL), and high-grade chondromalacia of the trochlea and the patella. Surgical treatment goals were to re-create a trochlear groove, restore bony restraint, and realign and offload the patella. First, a triplane tibial tubercle osteotomy (TTO) was performed, and the patella was everted 360° with a subvastus approach. The MPFL was reconstructed using a gracilis allograft. A fresh osteochondral allograft transplant trochlea was sized, and a 35-mm diameter graft was transplanted to re-create the groove. The TTO was secured in a new anterior, medial, and distal position. The patient was braced for 6 weeks and completed a rehabilitation protocol. At 9-month follow-up, she had made significant gains in range of motion (0°-140°) and activity compared to her preoperative status. She reported no pain or recurrent dislocations. Conclusion: This case demonstrates a viable surgical option for treatment of instability resulting from trochlear dysplasia with patellofemoral chondromalacia. The osteochondral allograft transplantation surgery technique allows patients to have a stable, pain-free knee joint and participate in activities compared to nonoperative management. However, the long-term outcomes of this procedure are unknown. PMID:27999505

  1. Metrological characterization of custom-designed 894.6 nm VCSELs for miniature atomic clocks.

    Science.gov (United States)

    Gruet, F; Al-Samaneh, A; Kroemer, E; Bimboes, L; Miletic, D; Affolderbach, C; Wahl, D; Boudot, R; Mileti, G; Michalzik, R

    2013-03-11

    We report on the characterization and validation of custom-designed 894.6 nm vertical-cavity surface-emitting lasers (VCSELs), for use in miniature Cs atomic clocks based on coherent population trapping (CPT). The laser relative intensity noise (RIN) is measured to be 1 × 10(-11) Hz(-1) at 10 Hz Fourier frequency, for a laser power of 700 μW. The VCSEL frequency noise is 10(13) · f(-1) Hz(2)/Hz in the 10 Hz VCSEL’s measured fractional frequency instability (Allan deviation) of ≈ 1 × 10(-8) at 1 s, and also is consistent with the VCSEL’s typical optical linewidth of 20-25 MHz. The VCSEL bias current can be directly modulated at 4.596 GHz with a microwave power of -6 to +6 dBm to generate optical sidebands for CPT excitation. With such a VCSEL, a 1.04 kHz linewidth CPT clock resonance signal is detected in a microfabricated Cs cell filled with Ne buffer gas. These results are compatible with state-of-the-art CPT-based miniature atomic clocks exhibiting a short-term frequency instability of 2-3 × 10(-11) at τ = 1 s and few 10(-12) at τ = 10(4) s integration time..

  2. Osteochondritis dissecans of the femoral head.

    Science.gov (United States)

    Siebenrock, Klaus A; Powell, James N; Ganz, Reinhold

    2010-01-01

    Seven patients with symptomatic osteochondritic lesions of the femoral head are presented. All were male with a mean age of 26 years (16 - 33 years). Two distinct morphologic appearances of the hip joint could be identified. Five patients presented with a coxa valga deformity, four of whom had signs of epiphyseal dysplasia. There were 2 patients whose hips appeared normal apart from the osteochondrontic lesions. In both cases an additional acetabular rim lesion due to a reproducible femoro-acetabular impingement was diagnosed at arthrotomy. This may have acted as the underlying cause of osteochondritis dissecans in these cases. All 7 patients underwent surgical treatment. An intertrochanteric osteotomy (I.O.) alone was performed in 2 patients. Follow-up of these patients at 6.5 and 8.5 years after surgery revealed that the osteochondritic lesions had not healed and one individual remained symptomatic. In the remaining 5 patients, treatment consisted of femoral head dislocation and screw fixation of the osteochondritic lesion. This was combined with an I.O. in two of these patients for coxa valga and osteoplasty of a broad femoral neck in 2 other patients. All lesions had healed at an average follow-up of 4.3 years (2 - 8.5 years). Three patients were asymptomatic and 2 patients had minor residual pain. No progressive osteoarthritic changes or signs of avascular necrosis of the femoral head were observed.

  3. Osteochondral lesions of the humeral trochlea in the young athlete

    Energy Technology Data Exchange (ETDEWEB)

    Marshall, Kelley W. [Pediatric Radiology of America, Roanoke, VA (United States); Children' s Healthcare of Atlanta at Scottish Rite, Atlanta, GA (United States); Children' s Diagnostic Imaging of Atlanta, P.C., Marietta, GA (United States); Marshall, David L.; Busch, Michael T. [Children' s Orthopaedics of Atlanta, P.C., Atlanta, GA (United States); Children' s Healthcare of Atlanta at Scottish Rite, Atlanta, GA (United States); Williams, Joseph P. [Children' s Healthcare of Atlanta at Scottish Rite, Atlanta, GA (United States); Children' s Diagnostic Imaging of Atlanta, P.C., Marietta, GA (United States)

    2009-05-15

    The purpose of this study was to characterize the variety of osteochondral abnormalities of the humeral trochlea in the pediatric athlete. Patients with trochlear abnormalities were identified through keyword search of radiology dictations from 1999 to 2007. The patient's medical record, imaging studies, and surgical reports were reviewed. The osteochondral lesions were categorized based on the imaging appearance. Surgical results were reviewed in conjunction with the imaging findings. Eighteen patients were identified. Trochlear lesions were stratified into two imaging groups: Osteochondral injury/osteochondritis dissecans (OCD) vs. avascular necrosis (AVN). The osteochondral injury group was stratified into medial and lateral trochlear abnormalities. The medial lesions (n=3) were small (<6 mm) and were located on the posterior articular surface of the medial trochlea. The lateral lesions (n=10) were larger (10-14 mm), circumscribed, and were located on the posterior inferior aspect of the lateral trochlea. Trochlear AVN (n=5) affected development of the lateral trochlea (type A) or both the medial and lateral aspects of the trochlea (type B). AVN occurred exclusively in athletes with history of remote distal humeral fracture. Seven of the 18 patients underwent elbow arthroscopy. Surgical findings and treatment regimens are summarized. Trochlear lesions should be considered in throwing athletes presenting with medial elbow pain and flexion contracture/extension block. Medial trochlear osteochondral injuries may result from posteromedial olecranon abutment. Lateral OCD lesions occur in a characteristic vascular watershed zone resulting from the unique blood supply of the trochlea. Trochlear AVN may be unmasked years following treated distal humeral fracture when the athletic demands upon the adolescent elbow increase, revealing the altered growth and biomechanics. (orig.)

  4. A novel system improves preservation of osteochondral allografts.

    Science.gov (United States)

    Cook, James L; Stoker, Aaron M; Stannard, James P; Kuroki, Keiichi; Cook, Cristi R; Pfeiffer, Ferris M; Bozynski, Chantelle; Hung, Clark T

    2014-11-01

    Osteochondral allografting is an option for successful treatment of large articular cartilage defects. Use of osteochondral allografting is limited by graft availability, often because of loss of chondrocyte viability during storage. The purpose of this study was to compare osteochondral allografts implanted in canine knees after 28 days or 60 days of storage for (1) initial (1 week) safety and feasibility; (2) integrity and positioning with time (12 weeks and 6 months); and (3) gross, cell viability, histologic, biochemical, and biomechanical characteristics at an endpoint of 6 months. With Institutional Animal Care and Use Committee approval, adult dogs (n=16) were implanted with 8-mm cylindrical osteochondral allografts in the lateral and medial femoral condyles of one knee. Osteochondral allografts preserved for 28 or 60 days using either the current tissue bank standard-of-care (SOC) or a novel system (The Missouri Osteochondral Allograft Preservation System, or MOPS) were used, creating four treatment groups: SOC 28-day, MOPS 28-day, SOC 60-day, and MOPS 60-day. Bacteriologic analysis of tissue culture and media were performed. Dogs were assessed by radiographs and arthroscopy at interim times and by gross, cell viability, histology, biochemistry, and biomechanical testing at the 6-month endpoint. With the numbers available, there was no difference in infection frequency during storage (5% for SOC and 3% for MOPS; p=0.5). No infected graft was implanted and no infections occurred in vivo. MOPS grafts had greater chondrocyte viability at Day 60 (90% versus 53%; p=0.002). For 60-day storage, MOPS grafts were as good as or better than SOC grafts with respect to all outcome measures assessed 6 months after implantation. Donor chondrocyte viability is important for osteochondral allograft success. MOPS allows preservation of chondrocyte viability for up to 60 days at sufficient levels to result in successful outcomes in a canine model of large femoral condylar

  5. Cartilage repair and subchondral bone migration using 3D printing osteochondral composites: a one-year-period study in rabbit trochlea.

    Science.gov (United States)

    Zhang, Weijie; Lian, Qin; Li, Dichen; Wang, Kunzheng; Hao, Dingjun; Bian, Weiguo; He, Jiankang; Jin, Zhongmin

    2014-01-01

    Increasing evidences show that subchondral bone may play a significant role in the repair or progression of cartilage damage in situ. However, the exact change of subchondral bone during osteochondral repair is still poorly understood. In this paper, biphasic osteochondral composite scaffolds were fabricated by 3D printing technology using PEG hydrogel and β-TCP ceramic and then implanted in rabbit trochlea within a critical size defect model. Animals were euthanized at 1, 2, 4, 8, 16, 24, and 52 weeks after implantation. Histological results showed that hyaline-like cartilage formed along with white smooth surface and invisible margin at 24 weeks postoperatively, typical tidemark formation at 52 weeks. The repaired subchondral bone formed from 16 to 52 weeks in a "flow like" manner from surrounding bone to the defect center gradually. Statistical analysis illustrated that both subchondral bone volume and migration area percentage were highly correlated with the gross appearance Wayne score of repaired cartilage. Therefore, subchondral bone migration is related to cartilage repair for critical size osteochondral defects. Furthermore, the subchondral bone remodeling proceeds in a "flow like" manner and repaired cartilage with tidemark implies that the biphasic PEG/β-TCP composites fabricated by 3D printing provides a feasible strategy for osteochondral tissue engineering application.

  6. Cartilage Repair and Subchondral Bone Migration Using 3D Printing Osteochondral Composites: A One-Year-Period Study in Rabbit Trochlea

    Directory of Open Access Journals (Sweden)

    Weijie Zhang

    2014-01-01

    Full Text Available Increasing evidences show that subchondral bone may play a significant role in the repair or progression of cartilage damage in situ. However, the exact change of subchondral bone during osteochondral repair is still poorly understood. In this paper, biphasic osteochondral composite scaffolds were fabricated by 3D printing technology using PEG hydrogel and β-TCP ceramic and then implanted in rabbit trochlea within a critical size defect model. Animals were euthanized at 1, 2, 4, 8, 16, 24, and 52 weeks after implantation. Histological results showed that hyaline-like cartilage formed along with white smooth surface and invisible margin at 24 weeks postoperatively, typical tidemark formation at 52 weeks. The repaired subchondral bone formed from 16 to 52 weeks in a “flow like” manner from surrounding bone to the defect center gradually. Statistical analysis illustrated that both subchondral bone volume and migration area percentage were highly correlated with the gross appearance Wayne score of repaired cartilage. Therefore, subchondral bone migration is related to cartilage repair for critical size osteochondral defects. Furthermore, the subchondral bone remodeling proceeds in a “flow like” manner and repaired cartilage with tidemark implies that the biphasic PEG/β-TCP composites fabricated by 3D printing provides a feasible strategy for osteochondral tissue engineering application.

  7. The use of custom-designed midfacial and submalar implants in the treatment of facial wasting syndrome.

    Science.gov (United States)

    Binder, William J; Bloom, David C

    2004-01-01

    Facial wasting syndrome is part of a lipodystrophy that occurs as a complication of highly active antiretroviral therapy. The loss of subcutaneous fat in the cheeks and temples results in a hollow-eyed, bony, emaciated appearance that is characteristic of the results of treatment of human immunodeficiency virus. Cessation of therapy results in a rebound in viral load and subsequent morbidity. The appearance of facial wasting syndrome is optimally treated with custom-designed implants that are made using high-resolution computed tomography combined with surgeon input and computer-aided design and manufacturing technology. Twenty-two patients with facial wasting syndrome were treated using either submalar implants (in more moderate cases) or custom-designed implants (in more severe cases). In each patient, the appearance of volumetric soft tissue restoration was successfully achieved, returning a permanent and more healthful appearance to the face.

  8. Enhancing Osteochondral Allograft Viability: Effects of Storage Media Composition

    National Research Council Canada - National Science Library

    Teng, Margie S; Yuen, Audrey S; Kim, Hubert T

    2008-01-01

    .... Bovine osteochondral grafts were stored at 4°C in lactated Ringer’s, Dulbecco’s modified eagle’s media (DMEM), DMEM supplemented with either insulin growth factor-1 or ZVAD-fmk, and a commercial storage media...

  9. The role of bone in osteochondral talar defects

    NARCIS (Netherlands)

    Reilingh, M.L.

    2016-01-01

    An osteochondral defect (OCD) of the talus often has a severe effect on the quality of life of young patients. This thesis aims to evaluate several aspects of etiology and treatment of talar OCDs. Part I of the thesis describes the natural history of OCDs and the development of subchondral bone

  10. Treatment of osteochondral lesions of the talus: a systematic review

    NARCIS (Netherlands)

    Zengerink, Maartje; Struijs, Peter A. A.; Tol, Johannes L.; van Dijk, Cornelis Niek

    2010-01-01

    The aim of this study was to summarize all eligible studies to compare the effectiveness of treatment strategies for osteochondral defects (OCD) of the talus. Electronic databases from January 1966 to December 2006 were systematically screened. The proportion of the patient population treated

  11. No superior treatment for primary osteochondral defects of the talus

    NARCIS (Netherlands)

    Dahmen, Jari; Lambers, Kaj T. A.; Reilingh, Mikel L.; van Bergen, Christiaan J. A.; Stufkens, Sjoerd A. S.; Kerkhoffs, Gino M. M. J.

    2017-01-01

    The purpose of this systematic literature review is to detect the most effective treatment option for primary talar osteochondral defects in adults. A literature search was performed to identify studies published from January 1996 to February 2017 using PubMed (MEDLINE), EMBASE, CDSR, DARE, and

  12. Surgical treatment of osteochondritis dissecans of the talus

    DEFF Research Database (Denmark)

    Zwingmann, Jörn; Südkamp, Norbert P; Schmal, Hagen

    2012-01-01

    PURPOSE: Osteochondritis dissecans (OCD) is an aseptic bone necrosis and represents pathology of high clinical relevance, which is frequently located on the talus. Various treatment strategies including non-surgical and surgical approaches have been described. An evidence-based treatment algorith...

  13. Osteochondral lesion of the bilateral femoral heads in a young athletic patient

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jung Eun; Ryu, Kyung Nam; Park, Ji Seon; Cho, Yoon Je [Kyung Hee University Hospital, Seoul (Korea, Republic of); Yoon, So Hee; Park, So Young; Jin, Wook [Dept. of Radiology, Kyung Hee University Hospital at Gangdong, Kyung Hee University College of Medicine, Seoul (Korea, Republic of); Lee, Kyung Ryeol [Dept. of Radiology, Jeju National University Hospital, Jeju (Korea, Republic of)

    2014-12-15

    Osteochondral lesions of the femoral head are uncommon and few studies have reported their imaging findings. Since joints are at risk of early degeneration after osteochondral damage, timely recognition is important. Osteochondral lesions of femoral head may often be necessary to differentiate from avascular necrosis. Here, we report a case of osteochondral lesions on bilateral femoral heads. This lesion manifested as subchondral cysts in initial radiographs, which led to further evaluation by computed tomography arthrography and magnetic resonance imaging, which revealed overlying cartilage defects.

  14. Characterizing restriction enzyme-associated loci in historic ragweed (Ambrosia artemisiifolia) voucher specimens using custom-designed RNA probes

    DEFF Research Database (Denmark)

    Sanchez Barreiro, Fatima; Garrett Vieira, Filipe Jorge; Martin, Michael David

    2017-01-01

    Population genetic studies of non-model organisms frequently employ reduced representation library (RRL) methodologies, many of which rely on protocols in which genomic DNA is digested by one or more restriction enzymes. However, because high molecular weight DNA is recommended for these protocols......, samples with degraded DNA are generally unsuitable for RRL methods. Given that ancient and historic specimens can provide key temporal perspectives to evolutionary questions, we explored how custom-designed RNA probes could enrich for RRL loci (Restriction Enzyme-Associated Loci baits, or REALbaits...

  15. Engineering

    National Research Council Canada - National Science Library

    Includes papers in the following fields: Aerospace Engineering, Agricultural Engineering, Chemical Engineering, Civil Engineering, Electrical Engineering, Environmental Engineering, Industrial Engineering, Materials Engineering, Mechanical...

  16. Autologous osteochondral graft for traumatic defects of finger joints.

    Science.gov (United States)

    Wu, W C; Fok, M W M; Fung, K Y; Tam, K H

    2012-03-01

    Finger joint defects in 16 adults were treated with an autologous osteochondral graft from the base of the second metacarpal, the radial styloid, the base of the third metacarpal or the trapezoid and these patients were followed up from between 12 and 62 months. There was no donor site morbidity. One patient had resorption of the graft and developed pain. The joint was subsequently fused. The mean range of movement was 55.8% of the opposite normal joint. At follow up, 15 patients had no discomfort or mild discomfort. Three had mild narrowing of the joint space and two had slight joint subluxation. Only two patients with concomitant severe injury to the same limb had difficulty performing daily activities. Ten were open injuries and these had poorer outcomes. A hemicondylar defect of a finger joint can be treated using an osteochondral graft obtained from the same hand.

  17. An Osteochondral Lesion of the Distal Tibia and Fibula in Patients With an Osteochondral Lesion of the Talus on MRI: Prevalence, Location, and Concomitant Ligament and Tendon Injuries.

    Science.gov (United States)

    You, Ja Yeon; Lee, Guen Young; Lee, Joon Woo; Lee, Eugene; Kang, Heung Sik

    2016-02-01

    The purpose of this study was to evaluate the prevalence and common location of a coexisting osteochondral lesion of the distal tibia and fibula and of associated abnormalities of the ankle ligaments and tendons on MRI in patients with an osteochondral lesion of the talus (OLT). A search of a database of MRI studies performed between July 2003 and January 2014 yielded MRI examinations of 297 feet with OLTs. Two readers reviewed the MRI examinations independently for the presence of an osteochondral lesion of the distal tibia and fibula and for concomitant ligament and tendon injuries. If an osteochondral lesion of the distal tibia and fibula was present, the reviewers also recorded the location (zones 1-10) and stage. Interobserver and intraobserver reliabilities were assessed using kappa statistics. The associations between a coexisting osteochondral lesion of the distal tibia and fibula and an OLT or a concomitant ankle injury were evaluated using the chi-square test. Readers A and B identified 61 (20.5%) and 47 (15.8%) coexisting osteochondral lesions of the distal tibia and fibula, respectively, with good interobserver (κ = 0.73) and excellent intraobserver (κ = 0.97) reliabilities. The most common location of a coexisting osteochondral lesion of the distal tibia and fibula was zone 4 (29.5%) by reader A and zone 2 (21.3%) by reader B. Stage I and stage IIA were common (> 85%). The frequency of osteochondral lesions of the distal tibia and fibula was not significantly different according to the location or stage of OLT. Abnormalities in the tibialis posterior tendon and in the anterior and posterior talofibular, calcaneofibular, and deltoid ligaments were significantly more common in patients with a coexisting osteochondral lesion of the distal tibia and fibula than in those with an isolated OLT (p lesion of the distal tibia and fibula is not rare on MRI in patients with an OLT and is related to a higher frequency of concomitant ankle ligament and tendon

  18. Repair of articular osteochondral defects of the knee joint using a composite lamellar scaffold.

    Science.gov (United States)

    Lv, Y M; Yu, Q S

    2015-04-01

    The major problem with repair of an articular cartilage injury is the extensive difference in the structure and function of regenerated, compared with normal cartilage. Our work investigates the feasibility of repairing articular osteochondral defects in the canine knee joint using a composite lamellar scaffold of nano-ß-tricalcium phosphate (ß-TCP)/collagen (col) I and II with bone marrow stromal stem cells (BMSCs) and assesses its biological compatibility. The bone-cartilage scaffold was prepared as a laminated composite, using hydroxyapatite nanoparticles (nano-HAP)/collagen I/copolymer of polylactic acid-hydroxyacetic acid as the bony scaffold, and sodium hyaluronate/poly(lactic-co-glycolic acid) as the cartilaginous scaffold. Ten-to 12-month-old hybrid canines were randomly divided into an experimental group and a control group. BMSCs were obtained from the iliac crest of each animal, and only those of the third generation were used in experiments. An articular osteochondral defect was created in the right knee of dogs in both groups. Those in the experimental group were treated by implanting the composites consisting of the lamellar scaffold of ß-TCP/col I/col II/BMSCs. Those in the control group were left untreated. After 12 weeks of implantation, defects in the experimental group were filled with white semi-translucent tissue, protruding slightly over the peripheral cartilage surface. After 24 weeks, the defect space in the experimental group was filled with new cartilage tissues, finely integrated into surrounding normal cartilage. The lamellar scaffold of ß-TCP/col I/col II was gradually degraded and absorbed, while new cartilage tissue formed. In the control group, the defects were not repaired. This method can be used as a suitable scaffold material for the tissue-engineered repair of articular cartilage defects. Cite this article: Bone Joint Res 2015;4:56-64. ©2015 The British Editorial Society of Bone & Joint Surgery.

  19. Multiscale strain analysis of tissue equivalents using a custom-designed biaxial testing device.

    Science.gov (United States)

    Bell, B J; Nauman, E; Voytik-Harbin, S L

    2012-03-21

    Mechanical signals transferred between a cell and its extracellular matrix play an important role in regulating fundamental cell behavior. To further define the complex mechanical interactions between cells and matrix from a multiscale perspective, a biaxial testing device was designed and built. Finite element analysis was used to optimize the cruciform specimen geometry so that stresses within the central region were concentrated and homogenous while minimizing shear and grip effects. This system was used to apply an equibiaxial loading and unloading regimen to fibroblast-seeded tissue equivalents. Digital image correlation and spot tracking were used to calculate three-dimensional strains and associated strain transfer ratios at macro (construct), meso, matrix (collagen fibril), cell (mitochondria), and nuclear levels. At meso and matrix levels, strains in the 1- and 2-direction were statistically similar throughout the loading-unloading cycle. Interestingly, a significant amplification of cellular and nuclear strains was observed in the direction perpendicular to the cell axis. Findings indicate that strain transfer is dependent upon local anisotropies generated by the cell-matrix force balance. Such multiscale approaches to tissue mechanics will assist in advancement of modern biomechanical theories as well as development and optimization of preconditioning regimens for functional engineered tissue constructs. Copyright © 2012 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  20. Composite scaffolds for osteochondral repair obtained by combination of additive manufacturing, leaching processes and hMSC-CM functionalization.

    Science.gov (United States)

    Díaz Lantada, Andrés; Alarcón Iniesta, Hernán; García-Ruíz, Josefa Predestinación

    2016-02-01

    Articular repair is a relevant and challenging area for the emerging fields of tissue engineering and biofabrication. The need of significant gradients of properties, for the promotion of osteochondral repair, has led to the development of several families of composite biomaterials and scaffolds, using different effective approaches, although a perfect solution has not yet been found. In this study we present the design, modeling, rapid manufacturing and in vitro testing of a composite scaffold aimed at osteochondral repair. The presented composite scaffold stands out for having a functional gradient of density and stiffness in the bony phase, obtained in titanium by means of computer-aided design combined with additive manufacture using selective laser sintering. The chondral phase is obtained by sugar leaching, using a PDMS matrix and sugar as porogen, and is joined to the bony phase during the polymerization of PDMS, therefore avoiding the use of supporting adhesives or additional intermediate layers. The mechanical performance of the construct is biomimetic and the stiffness values of the bony and chondral phases can be tuned to the desired applications, by means of controlled modifications of different parameters. A human mesenchymal stem cell (h-MSC) conditioned medium (CM) is used for improving scaffold response. Cell culture results provide relevant information regarding the viability of the composite scaffolds used. Copyright © 2015 Elsevier B.V. All rights reserved.

  1. Treatment of osteochondral lesions of the talus: a systematic review.

    Science.gov (United States)

    Zengerink, Maartje; Struijs, Peter A A; Tol, Johannes L; van Dijk, Cornelis Niek

    2010-02-01

    The aim of this study was to summarize all eligible studies to compare the effectiveness of treatment strategies for osteochondral defects (OCD) of the talus. Electronic databases from January 1966 to December 2006 were systematically screened. The proportion of the patient population treated successfully was noted, and percentages were calculated. For each treatment strategy, study size weighted success rates were calculated. Fifty-two studies described the results of 65 treatment groups of treatment strategies for OCD of the talus. One randomized clinical trial was identified. Seven studies described the results of non-operative treatment, 4 of excision, 13 of excision and curettage, 18 of excision, curettage and bone marrow stimulation (BMS), 4 of an autogenous bone graft, 2 of transmalleolar drilling (TMD), 9 of osteochondral transplantation (OATS), 4 of autologous chondrocyte implantation (ACI), 3 of retrograde drilling and 1 of fixation. OATS, BMS and ACI scored success rates of 87, 85 and 76%, respectively. Retrograde drilling and fixation scored 88 and 89%, respectively. Together with the newer techniques OATS and ACI, BMS was identified as an effective treatment strategy for OCD of the talus. Because of the relatively high cost of ACI and the knee morbidity seen in OATS, we conclude that BMS is the treatment of choice for primary osteochondral talar lesions. However, due to great diversity in the articles and variability in treatment results, no definitive conclusions can be drawn. Further sufficiently powered, randomized clinical trials with uniform methodology and validated outcome measures should be initiated to compare the outcome of surgical strategies for OCD of the talus.

  2. Comparison of arthroscopic osteochondral substitute grafting and remplissage for engaging Hill-Sachs lesions.

    Science.gov (United States)

    Garcia, Grant H; Park, Min Jung; Baldwin, Keith; Fowler, John; Kelly, John D; Tjoumakaris, Fotios P

    2013-01-01

    The optimum management for recurrent glenohumeral instability with significant humeral head defects remains controversial. The purpose of this study was to compare outcomes and recurrence rates between patients who underwent osteochondral substitute grafting and patients who underwent remplissage to treat recurrent shoulder instability from an engaging Hill-Sachs defect with a Bankart lesion. Twenty consecutive patients who underwent remplissage and 19 consecutive patients who underwent osteochondral substitute grafting with Bankart repair were studied. Mean follow-up was 29.6 months for the remplissage group and 32.1 months for the osteochondral substitute grafting group. All patients had an engaging Hill-Sachs lesion, and indications for surgery were identical between groups. Three postoperative recurrences occurred in the remplissage group and 6 occurred in the osteochondral substitute grafting group (P=.18). Nineteen patients in the remplissage group and 7 patients in the osteochondral substitute grafting group had a large humeral head defect. Patients in the remplissage group had better Western Ontario Shoulder Instability Index [WOSI] scores than those in the osteochondral substitute grafting group for large lesions (74.7 vs 50.4, respectively), although they were not statistically significant (P=.077). After controlling for age, sex, lesion size, and follow-up differences, the remplissage group reported significantly better WOSI scores (P=.016). This study demonstrated a potential advantage of remplissage compared with osteochondral synthetic grafting in patients who experienced recurrent anterior shoulder instability, particularly in shoulders with a large humeral head defect. Copyright 2013, SLACK Incorporated.

  3. Optimising femoral-head osteochondral allograft transplantation in a preclinical model

    Directory of Open Access Journals (Sweden)

    Brett D. Crist

    2016-04-01

    Conclusion: These data provide initial translational and clinical evidence for large osteochondral allografts as a potential option for functional resurfacing of full-thickness cartilage defects of the femoral head.

  4. Clinical Outcome After Arthroscopic Debridement and Microfracture for Osteochondritis Dissecans of the Capitellum

    NARCIS (Netherlands)

    Bexkens, Rens; van den Ende, Kim I. M.; Ogink, Paul T.; van Bergen, Christiaan J. A.; van den Bekerom, Michel P. J.; Eygendaal, Denise

    2017-01-01

    Background: Various surgical treatment techniques have been developed to treat capitellar osteochondritis dissecans; however, the optimal technique remains the subject of ongoing debate. Purpose: To evaluate clinical outcomes after arthroscopic debridement and microfracture for advanced capitellar

  5. Osteochondritis dissecans of the medial femoral condyle : New cell-free scaffold as a treatment option.

    Science.gov (United States)

    Stadler, N; Trieb, K

    2016-08-01

    There is no gold standard in treating osteochondral lesions, which is why the treatment remains very challenging. Osteochondral defects can occur in any joint, but the most common locations are the knee and the ankle. Trauma, repeated microtrauma, avascular necrosis and osteochondritis dissecans (a special type of avascular necrosis) are blamed for the cartilage damage and the damage of adjacent subchondral bone. The self-healing ability of the cartilage is unfortunately very poor; thus, it is necessary to develop new methods of cartilage repair. Unfortunately, few data and long-term survival rates for these new scaffolds are available. We report a case of osteochondritis dissecans treated with a new cell-free scaffold MaioRegen® (Fin-Ceramica Faenza Spa, Faenza, Italy).

  6. Fixation of an osteochondral fragment after acute patellar dislocation in an immature skeleton,

    Directory of Open Access Journals (Sweden)

    Rodrigo Pires e Albuquerque

    2014-04-01

    Full Text Available Fixation of an osteochondral fracture after acute patellar dislocation is an infrequent form of treatment. Likewise, the location of this fragment in the lateral region of the lateral femoral condyle, functioning as a free body, is uncommon. The aim of this study was to present a case of osteochondral fracture of the patella at an unusual site, along with the therapy used and the clinical follow-up.

  7. Transmalleolar Approach for Arthroscopy-Assisted Headless Screw Fixation of an Osteochondral Talar Dome Fracture.

    Science.gov (United States)

    Izadi, Ebrahim; Anwar, Rahij; Phillips, Sarah; Kavarthapu, Venu

    2018-02-15

    Displaced osteochondral fractures of the body of talus quite often require a malleolar osteotomy to gain access to the fracture fragment during internal fixation. We describe a case report in which access to a displaced osteochondral fracture of the lateral talar dome was achieved using an arthroscopy-assisted fibular tunnel approach. This technique resulted in satisfactory fracture healing and a satisfactory clinical outcome. Copyright © 2017 The American College of Foot and Ankle Surgeons. All rights reserved.

  8. Current concepts in the diagnosis and treatment of osteochondral lesions of the ankle.

    Science.gov (United States)

    O'Loughlin, Padhraig F; Heyworth, Benton E; Kennedy, John G

    2010-02-01

    Osteochondral lesions of the ankle are a more common source of ankle pain than previously recognized. Although the exact pathophysiology of the condition has not been clearly established, it is likely that a variety of etiological factors play a role, with trauma, typically from ankle sprains, being the most common. Technological advancements in ankle arthroscopy and radiologic imaging, most importantly magnetic resonance imaging, have improved diagnostic capabilities for detecting osteochondral lesions of the ankle. Moreover, these technologies have allowed for the development of more sophisticated classification systems that may, in due course, direct specific future treatment strategies. Nonoperative treatment yields best results when employed in select pediatric and adolescent patients with osteochondritis dissecans. However, operative treatment, which is dependent on the size and site of the lesion, as well as the presence or absence of cartilage damage, is frequently warranted in both children and adults with osteochondral lesions. Arthroscopic microdrilling, micropicking, and open procedures, such as osteochondral autograft transfer system and matrix-induced autologous chondrocyte implantation, are frequently employed. The purpose of this article is to review the history, etiology, and classification systems for osteochondral lesions of the ankle, as well as to describe current approaches to diagnosis and management.

  9. Bi-layer collagen/microporous electrospun nanofiber scaffold improves the osteochondral regeneration.

    Science.gov (United States)

    Zhang, Shufang; Chen, Longkun; Jiang, Yangzi; Cai, Youzhi; Xu, Guowei; Tong, Tong; Zhang, Wei; Wang, Linlin; Ji, Junfeng; Shi, Peihua; Ouyang, Hong Wei

    2013-07-01

    An optimal scaffold is crucial for osteochondral regeneration. Collagen and electrospun nanofibers have been demonstrated to facilitate cartilage and bone regeneration, respectively. However, the effect of combining collagen and electrospun nanofibers on osteochondral regeneration has yet to be evaluated. Here, we report that the combination of collagen and electrospun poly-l-lactic acid nanofibers synergistically promotes osteochondral regeneration. We first fabricated bi-layer microporous scaffold with collagen and electrospun poly-l-lactic acid nanofibers (COL-nanofiber). Mesenchymal stem cells were cultured on the bi-layer scaffold and their adhesion, proliferation and differentiation were examined. Moreover, osteochondral defects were created in rabbits and implanted with COL-nanofiber scaffold. Cartilage and subchondral bone regeneration were evaluated at 6 and 12weeks after surgery. Compared with COL scaffold, cells on COL-nanofiber scaffold exhibited more robust osteogenic differentiation, indicated by higher expression levels of OCN and runx2 genes as well as the accumulation of calcium nodules. Furthermore, implantation of COL-nanofiber scaffold seeded with cells induced more rapid subchondral bone emergence, and better cartilage formation, which led to better functional repair of osteochondral defects as manifested by histological staining, biomechanical test and micro-computed tomography data. Our study underscores the potential of using the bi-layer microporous COL-nanofiber scaffold for the treatment of deep osteochondral defects. Copyright © 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  10. Contaminated osteochondral plugs: effect of different sterilizing solutions: an experimental study in the rabbit

    Directory of Open Access Journals (Sweden)

    Hamidreza Yazdi

    2012-11-01

    Full Text Available  Abstract Background: To determine the efficacy of different antiseptic solutions (Control group (I, Antibiotic solution (II, Chlorhexidine 0.4% (III, and povidone – iodine 10% (IV in sterilizing contaminated osteochondral plugs. Methods: Under sterile conditions, the femoral head and condyles of 20 rabbits were removed and cut into equal osteochondral pieces. A total of 200 osteochondral specimens were obtained. All 200 specimens were dropped on the operating room floor for fifteen seconds and assigned to one of four experimental groups. Group I samples were cultured after washing with normal saline solution (Control group. In other three groups, prior to culturing process, samples were placed in an antibiotic solution after washing with normal saline (Neomycin & Polymyxin (group II, Chlorhexidine 0.4% (group III, and povidone – iodine 10% (group IV, respectively. Results: In group I, 25 of 50 specimens had positive cultures. Of 50 specimens of group II, III and IV, no positive cultures were found after 10 days. Conclusion: all three agents including antibiotic solution, povidone-iodine 10% and chlorhexidine 0.4% seem effective in sterilizing the contaminated osteochondral samples. According to the literature, povidone-iodine has no negative effect on the cartilage metabolism and seems to be a proper choice of decontaminating solution for osteochondral plugs.To the best of the authors' knowledge, such a study on the contaminated osteochondral specimen has not been previously reported in the literature. 

  11. Characterizing restriction enzyme-associated loci in historic ragweed (Ambrosia artemisiifolia) voucher specimens using custom-designed RNA probes.

    Science.gov (United States)

    Sánchez Barreiro, Fátima; Vieira, Filipe G; Martin, Michael D; Haile, James; Gilbert, M Thomas P; Wales, Nathan

    2017-03-01

    Population genetic studies of nonmodel organisms frequently employ reduced representation library (RRL) methodologies, many of which rely on protocols in which genomic DNA is digested by one or more restriction enzymes. However, because high molecular weight DNA is recommended for these protocols, samples with degraded DNA are generally unsuitable for RRL methods. Given that ancient and historic specimens can provide key temporal perspectives to evolutionary questions, we explored how custom-designed RNA probes could enrich for RRL loci (Restriction Enzyme-Associated Loci baits, or REALbaits). Starting with genotyping-by-sequencing (GBS) data generated on modern common ragweed (Ambrosia artemisiifolia L.) specimens, we designed 20 000 RNA probes to target well-characterized genomic loci in herbarium voucher specimens dating from 1835 to 1913. Compared to shotgun sequencing, we observed enrichment of the targeted loci at 19- to 151-fold. Using our GBS capture pipeline on a data set of 38 herbarium samples, we discovered 22 813 SNPs, providing sufficient genomic resolution to distinguish geographic populations. For these samples, we found that dilution of REALbaits to 10% of their original concentration still yielded sufficient data for downstream analyses and that a sequencing depth of ~7m reads was sufficient to characterize most loci without wasting sequencing capacity. In addition, we observed that targeted loci had highly variable rates of success, which we primarily attribute to similarity between loci, a trait that ultimately interferes with unambiguous read mapping. Our findings can help researchers design capture experiments for RRL loci, thereby providing an efficient means to integrate samples with degraded DNA into existing RRL data sets. © 2016 John Wiley & Sons Ltd.

  12. Osteochondritis dissecans (OCD), an endoplasmic reticulum storage disease?

    DEFF Research Database (Denmark)

    Skagen, Peter Storgaard; Horn, T; Kruse, H A

    2011-01-01

    Osteochondritis dissecans (OCD) fragments, cartilage and blood from four patients were used for morphological and molecular analysis. Controls included articular cartilage and blood samples from healthy individuals. Light microscopy and transmission electron microscopy (TEM) showed abnormalities...... in chondrocytes and extracellular matrix of cartilage from OCD patients. Abnormal type II collagen heterofibrils in "bundles" and chondrocytes with abnormal accumulation of matrix proteins in distended rough endoplasmic reticulum were typical findings. Further, Von Kossa staining and TEM showed empty lacunae...... polymorphism was found within the COL2A1 gene for one patient. We suggest that OCD lesions are caused by an alteration in chondrocyte matrix synthesis causing an endoplasmic reticulum storage disease phenotype, which disturbs or abrupts endochondral ossification....

  13. Stifle osteochondritis dissecans in snow leopards (Uncia uncia).

    Science.gov (United States)

    Herrin, Kimberly Vinette; Allan, Graeme; Black, Anthony; Aliah, Rhonda; Howlett, Cameron Rolfe

    2012-06-01

    Three snow leopard (Uncia uncia) cubs, female and male siblings and an unrelated female, had lameness attributed to osteochondritis dissecans (OCD) lesions noted at 6, 8, and 10 mo of age, respectively. All cubs were diagnosed with OCD via radiographs. The sibling cubs both had lesions of the right lateral femoral condyles, while the unrelated cub had bilateral lesions of the lateral femoral condyles. Subsequently, OCD was confirmed in all three cases during surgical correction of the lateral femoral condyle lesions via lateral stifle arthrotomies, flap removal, and debridement of the defect sites. Histopathology also supported the diagnosis of OCD. Postoperatively, the sibling cubs developed seromas at the incision sites and mild lameness, which resolved within a month. To date, two cubs have been orthopedically sound, while one of the sibling cubs has developed mild osteoarthritis. OCD has rarely been reported in domestic felids, and to the authors' knowledge these are the first reported cases of OCD in nondomestic felids.

  14. Custom-designed orthopedic implants evaluated using finite element analysis of patient-specific computed tomography data: femoral-component case study

    OpenAIRE

    Nayfeh Jamal F; Hosni Yasser A; Harrysson Ola LA

    2007-01-01

    Abstract Background Conventional knee and hip implant systems have been in use for many years with good success. However, the custom design of implant components based on patient-specific anatomy has been attempted to overcome existing shortcomings of current designs. The longevity of cementless implant components is highly dependent on the initial fit between the bone surface and the implant. The bone-implant interface design has historically been limited by the surgical tools and cutting gu...

  15. The effect of platelet-rich plasma on autologous osteochondral transplantation: an in vivo rabbit model.

    Science.gov (United States)

    Smyth, Niall A; Haleem, Amgad M; Murawski, Christopher D; Do, Huong T; Deland, Jonathan T; Kennedy, John G

    2013-12-18

    Autologous osteochondral transplantation restores a cartilage defect with a cylindrical unit of bone and articular cartilage. Previous studies have described poor graft integration at the chondral interface and degeneration of the cartilage. This has prompted the investigation of adjuncts to address these concerns, including platelet-rich plasma (PRP), which has the potential to improve chondral interface integration and decrease cartilage degeneration. The purpose of this study was to evaluate the effect of PRP on autologous osteochondral transplantation in a rabbit model. Bilateral osteochondral defects (2.7 mm in diameter and 5 mm in depth) were created on the femoral condyles of twelve New Zealand White rabbits. Osteochondral grafts were harvested from the ipsilateral femoral condyle and, after randomization, were treated with either PRP or saline solution before implantation into the defect site. The rabbits were killed at three, six, or twelve weeks postoperatively. The osteochondral graft was assessed using the International Cartilage Repair Society (ICRS) macroscopic and modified ICRS histological scoring systems. Macroscopic assessment revealed no significant difference between the two groups (mean and standard deviation, 11.2 ± 0.9 for the PRP-treated group versus 10.3 ± 0.9 for the control group; p = 0.09). The mean modified ICRS histological score was significantly higher overall and at each time point for the PRP-treated osteochondral transplants compared with the controls (overall mean, 18.2 ± 2.7 versus 13.5 ± 3.3; p = 0.002). Assessing graft integration specifically, the mean score for the PRP-treated group was significantly higher than that for the control group (2.5 ± 0.9 versus 1.6 ± 0.7; p = 0.004). No adverse events occurred as a result of the surgical procedure or PRP. PRP may improve the integration of an osteochondral graft at the cartilage interface and decrease graft degeneration in an in vivo animal model. The use of PRP as a

  16. The clinical outcomes of mosaicplasty in the treatment of osteochondritis dissecans of the distal humeral capitellum of young athletes

    DEFF Research Database (Denmark)

    Ovesen, Janne; Olsen, Bo Sanderhoff; Johannsen, Hans

    2011-01-01

    The purpose of this study was to evaluate the clinical outcomes of mosaicplasty in the treatment of osteochondritis dissecans of the distal humeral capitellum.......The purpose of this study was to evaluate the clinical outcomes of mosaicplasty in the treatment of osteochondritis dissecans of the distal humeral capitellum....

  17. Influence of basal support and early loading on bone cartilage healing in press-fitted osteochondral autografts

    NARCIS (Netherlands)

    Nosewicz, Tomasz L.; Reilingh, Mikel L.; Wolny, Martin; van Dijk, C. Niek; Duda, Georg N.; Schell, Hanna

    2014-01-01

    The influence of basal graft support combined to early loading following an osteochondral autograft procedure is unclear. It was hypothesized that bottomed grafts may allow for early mobilization by preventing graft subsidence and leading to better healing. Osteochondral autografts were press fitted

  18. Design of a Novel 3D Printed Bioactive Nanocomposite Scaffold for Improved Osteochondral Regeneration.

    Science.gov (United States)

    Castro, Nathan J; Patel, Romil; Zhang, Lijie Grace

    2015-09-01

    Chronic and acute osteochondral defects as a result of osteoarthritis and trauma present a common and serious clinical problem due to the tissue's inherent complexity and poor regenerative capacity. In addition, cells within the osteochondral tissue are in intimate contact with a 3D nanostructured extracellular matrix composed of numerous bioactive organic and inorganic components. As an emerging manufacturing technique, 3D printing offers great precision and control over the microarchitecture, shape and composition of tissue scaffolds. Therefore, the objective of this study is to develop a biomimetic 3D printed nanocomposite scaffold with integrated differentiation cues for improved osteochondral tissue regeneration. Through the combination of novel nano-inks composed of organic and inorganic bioactive factors and advanced 3D printing, we have successfully fabricated a series of novel constructs which closely mimic the native 3D extracellular environment with hierarchical nanoroughness, microstructure and spatiotemporal bioactive cues. Our results illustrate several key characteristics of the 3D printed nanocomposite scaffold to include improved mechanical properties as well as excellent cytocompatibility for enhanced human bone marrow-derived mesenchymal stem cell adhesion, proliferation, and osteochondral differentiation in vitro. The present work further illustrates the effectiveness of the scaffolds developed here as a promising and highly tunable platform for osteochondral tissue regeneration.

  19. Selective laser sintering scaffold with hierarchical architecture and gradient composition for osteochondral repair in rabbits.

    Science.gov (United States)

    Du, Yingying; Liu, Haoming; Yang, Qin; Wang, Shuai; Wang, Jianglin; Ma, Jun; Noh, Insup; Mikos, Antonios G; Zhang, Shengmin

    2017-08-01

    Osteochondral defects cannot be adequately self-repaired due to the presence of the sophisticated hierarchical structure and the lack of blood supply in cartilage. Thus, one of the major challenges remaining in this field is the structural design of a biomimetic scaffold that satisfies the specific requirements for osteochondral repair. To address this hurdle, a bio-inspired multilayer osteochondral scaffold that consisted of the poly(ε-caprolactone) (PCL) and the hydroxyapatite (HA)/PCL microspheres, was constructed via selective laser sintering (SLS) technique. The SLS-derived scaffolds exhibited an excellent biocompatibility to support cell adhesion and proliferation in vitro. The repair effect was evaluated by implanting the acellular multilayer scaffolds into osteochondral defects of a rabbit model. Our findings demonstrated that the multilayer scaffolds were able to induce articular cartilage formation by accelerating the early subchondral bone regeneration, and the newly formed tissues could well integrate with the native tissues. Consequently, the current study not only achieves osteochondral repair, but also suggests a promising strategy for the fabrication of bio-inspired multilayer scaffolds with well-designed architecture and gradient composition via SLS technique. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. TREATMENT OF OSTEOCHONDRAL LESIONS OF THE TALUS BY MEANS OF THEARTHROSCOPY-ASSISTED MICROPERFORATION TECHNIQUE

    Science.gov (United States)

    de Lima, Everton; de Queiroz, Felipe; Lopes, Osmar Valadão; Spinelli, Leandro de Freitas

    2015-01-01

    Objective: To evaluate patients affected by osteochondral fractures of the talus who were treated surgically by means of arthroscopy-assisted microperforation. Methods: A retrospective study was carried out on 24 patients with osteochondral lesions of the talus who underwent microperforation assisted by videoarthroscopy of the ankle. They were evaluated using the American Orthopaedic Foot and Ankle Society (AOFAS) score system before and after the operation. Results: There were 19 men and 5 women, with a mean age of 35.3 years (minimum of 17 years and maximum of 54 years). The minimum follow-up was two years (maximum of 39 months). All the patients showed an improvement in AOFAS score after surgery, with an average improvement of around 22.5 points. Conclusion: Videoarthroscopy-assisted microperforation is a good option for treating osteochondral lesions of the talus and provides good functional results. PMID:27027076

  1. Fresh osteochondral allografts-procurement and tissue donation in Europe.

    Science.gov (United States)

    Schmidt, S; Schulte, A; Schwarz, S; Hofmann, N; Tietz, S; Boergel, M; Sixt, S U

    2017-07-01

    Fresh osteochondral allografts are a well-established treatment for large, full-thickness cartilage defects. The clinical outcome for carefully selected patients is very favorable, especially for the young and active and graft survival up to 25 years has been described in the literature. Furthermore, a high patient satisfaction rate has been reported, but the biggest obstacle to overcome is the availability of tissue for transplantation. Large fresh bone allografts for cartilage damage repair only can be harvested from organ donors following organ removal or cadaveric donors, preferably in the setting of an operation room to minimize possible contamination of the tissue. Apart from the logistic challenges this entails, an experienced recovery team is needed. Furthermore, the public as well as medical staff is much less aware of the possibility and requirements of tissue donation than organ donation and families of deceased are rarely approached for bone and cartilage donation. This review aims to highlight the current situation of organ and tissue donation in Europe with special focus on the processing of bones and possible safety and quality concerns. We analyze what may prevent consent and what might be done to improve the situation of tissue donation. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Fresh Osteochondral Allograft Versus Autograft: Twelve-Month Results in Isolated Canine Knee Defects.

    Science.gov (United States)

    McCarty, Eric C; Fader, Ryan R; Mitchell, Justin J; Glenn, R Edward; Potter, Hollis G; Spindler, Kurt P

    2016-09-01

    Osteochondral autografts and allografts have been widely used in the treatment of isolated grade 4 articular cartilage lesions of the knee. However, there is a paucity of literature regarding the basic science investigating the direct comparison between fresh osteochondral allografts to autografts. At 12 months, fresh osteochondral allografts are equal to autografts with respect to function, bony incorporation into host bone, and chondrocyte viability. Controlled laboratory study. Eight adult mongrel dogs underwent bilateral hindlimb osteochondral graft implantation in the knee after creation of an acute Outerbridge grade 4 cartilage defect. One hindlimb of each dog knee received an autograft, and the contralateral knee received an allograft. All dogs were sacrificed at 12 months. Graft analysis included gross examination, radiographs, magnetic resonance imaging (MRI), biomechanical testing, and histology. MRI demonstrated excellent bony incorporation of both autografts and allografts, except for 1 allograft that revealed partial incorporation. Histologic examination of cartilage showed intact hyaline appearance for both autografts and allografts, with fibrocartilage at the host-graft interface of both. Biomechanical testing demonstrated no significant difference between allografts and autografts (P = .76). Furthermore, no significant difference was observed between allografts and the native cartilage with biomechanical testing (P = .84). After 12 months from time of implantation, fresh osteochondral allograft tissue and autograft tissue in this study were not statistically different with respect to biomechanical properties, gross morphology, bony incorporation, or overall histologic characteristics. When compared with the previously reported 6-month incorporation rates, there was improved allograft and autograft incorporation at 12 months. With no significant differences in gross examination, radiographs, MRI, biomechanical testing, or histology in the canine

  3. Surface energy and stiffness discrete gradients in additive manufactured scaffolds for osteochondral regeneration.

    Science.gov (United States)

    Di Luca, Andrea; Longoni, Alessia; Criscenti, Giuseppe; Lorenzo-Moldero, Ivan; Klein-Gunnewiek, Michel; Vancso, Julius; van Blitterswijk, Clemens; Mota, Carlos; Moroni, Lorenzo

    2016-02-27

    Swift progress in biofabrication technologies has enabled unprecedented advances in the application of developmental biology design criteria in three-dimensional scaffolds for regenerative medicine. Considering that tissues and organs in the human body develop following specific physico-chemical gradients, in this study, we hypothesized that additive manufacturing (AM) technologies would significantly aid in the construction of 3D scaffolds encompassing such gradients. Specifically, we considered surface energy and stiffness gradients and analyzed their effect on adult bone marrow derived mesenchymal stem cell differentiation into skeletal lineages. Discrete step-wise macroscopic gradients were obtained by sequentially depositing different biodegradable biomaterials in the AM process, namely poly(lactic acid) (PLA), polycaprolactone (PCL), and poly(ethylene oxide terephthalate)/poly(butylene terephthalate) (PEOT/PBT) copolymers. At the bulk level, PEOT/PBT homogeneous scaffolds supported a higher alkaline phosphatase (ALP) activity compared to PCL, PLA, and gradient scaffolds, respectively. All homogeneous biomaterial scaffolds supported also a significantly higher amount of glycosaminoglycans (GAGs) production compared to discrete gradient scaffolds. Interestingly, the analysis of the different material compartments revealed a specific contribution of PCL, PLA, and PEOT/PBT to surface energy gradients. Whereas PEOT/PBT regions were associated to significantly higher ALP activity, PLA regions correlated with significantly higher GAG production. These results show that cell activity could be influenced by the specific spatial distribution of different biomaterial chemistries in a 3D scaffold and that engineering surface energy discrete gradients could be considered as an appealing criterion to design scaffolds for osteochondral regeneration.

  4. The Golf Ball Sign: Arthroscopic Localization of an Osteochondritis Dissecans Lesion of the Knee

    OpenAIRE

    Piposar, Jonathan; Sutton, Karen

    2014-01-01

    We report on the arthroscopic treatment of a 12-year-old boy diagnosed with an osteochondral defect of the medial femoral condyle. He underwent arthroscopic fixation of the defect, and during the surgery, a blunt trocar was used to localize the lesion. The trocar created a transient dimpling effect on the cartilage overlying the osteochondral defect that resembled the surface of a golf ball. This “golf ball sign” then served as a visual guide during placement of a chondral dart. When present,...

  5. Concentrations of stromal cell-derived factor-1 in serum, plasma, and synovial fluid of horses with osteochondral injury.

    Science.gov (United States)

    Dymock, David C; Brown, Murray P; Merritt, Kelly A; Trumble, Troy N

    2014-08-01

    To determine whether stromal cell-derived factor-1 (SDF-1) concentrations in serum, plasma, and synovial fluid differed among untrained, race-trained, and osteochondral-injured Thoroughbred racehorses. 22 racehorses without osteochondral injury and 37 racehorses with osteochondral injury. Horses without osteochondral injury were examined before and after 5 to 6 months of race training. Horses with osteochondral injury were undergoing arthroscopic surgery for removal of osteochondral fragments from carpal or metacarpophalangeal or metatarsophalangeal joints (fetlock joints). Serum, plasma, and fetlock or carpal synovial fluid samples were obtained and analyzed for SDF-1 concentration by use of an ELISA. In horses with fetlock or carpal joint injury, mean synovial fluid SDF-1 concentrations were significantly higher, serum SDF-1 concentrations were significantly lower, and synovial fluid-to-serum SDF-1 ratios were significantly higher than in untrained and trained horses. Synovial fluid SDF-1 concentrations were not significantly different between trained and untrained horses. Plasma SDF-1 concentrations were not different among the 3 groups. Results obtained with serum, compared with synovial fluid and plasma, had better sensitivity for differentiating between osteochondral-injured horses and uninjured horses. In horses with fetlock joint osteochondral injury, serum SDF-1 concentrations were correlated with radiographic and arthroscopic inflammation scores, but not arthroscopic cartilage scores. Results suggested that serum SDF-1 concentrations were more sensitive than plasma and synovial fluid concentrations for detection of osteochondral injury in the fetlock or carpal joint of racehorses. Analysis of serum and synovial SDF-1 concentrations in horses with experimentally induced joint injury may help define the onset and progression of post-traumatic osteoarthritis and aid in the evaluation of anti-inflammatory treatments.

  6. Fluoro-Free navigated retrograde drilling of osteochondral lesions.

    Science.gov (United States)

    Gras, Florian; Marintschev, Ivan; Kahler, David M; Klos, Kajetan; Mückley, Thomas; Hofmann, Gunther O

    2011-01-01

    Retrograde drilling of osteochondral lesions (OCLs) is a recommended, but demanding operative approach for revascularization of lesions in stage 1-3 according to Berndt and Harty after failed conservative treatment. The gold standard of intraoperative driller guidance is fluoroscopic control. Limitations are a 2D visualization of a 3D procedure and sometimes limited view of the OCL in fluoroscopy, leading to increased radiation exposure. A new image-free navigation procedure was evaluated for practicability and precision in first clinical applications. In a period of 7 months, retrograde drillings were performed in eight patients (3x femoral condyle, 5x talus) using the new Fluoro-Free navigation procedure without rigidly fixed reference bases. In total, 29 retrograde drillings were performed without any technical problem. The overall mean operating time was 82.1 ± 29.3 min (34.6 ± 6.4 min for the standard arthroscopy and 11.2 ± 1.2 min per drill). Twenty-seven of 29 drillings hit the target with a 100% first-pass accuracy. Two complications during drilling (one navigation specific and one navigation independent) were observed. The paper describes the promising first clinical applications of a new Fluoro-Free navigation procedure for the retrograde drilling of OCLs determined by arthroscopy. The benefit of that navigated drillings with a high rate of first-pass accuracy and no need for radiation exposure in contrast to standard techniques is highlighted.

  7. Extra-articular synovial fluid extravasation following operative fixation of an osteochondral fracture of the patella.

    Science.gov (United States)

    Marberry, Kevin M; Ginsburg, Zach

    2012-08-01

    Osteochondral fracture of the patella following a lateral patellar dislocation can be treated with operative and nonoperative techniques that are dictated by the clinical presentation. In the presence of large fragments following acute fractures, arthroscopic retrieval and fixation are advocated, whereas smaller displaced fragments may be removed and discarded as loose bodies. Several methods of fixation exist for osteochondral fractures of the patella, including the use of cannulated and noncannulated screws.This article describes a case of an elite competitive swimmer who sustained a lateral patellar dislocation with a large osteochondral fracture of the patella that was treated with open reduction and fixation using absorbable cannulated screws in an inside-out fashion. In the early postoperative period, the patient developed a symptomatic synovial fluid fistula through a cannulated screw to the prepatellar space. The diagnosis of this condition was made clinically and confirmed with noncontrast magnetic resonance imaging 6 weeks postoperatively. The symptoms of pain, skin erythema, and swelling were self-limited and eventually resolved with observation, allowing the athlete to return to his previous activity level. Magnetic resonance imaging 3 years postoperatively showed the complete resolution of the fluid extravasation. Extra-articular synovial fluid extravasation is as a rare complication following routine knee arthroscopy, accounting for 3.2% of the complications. This article describes a rare, self-limited complication following open fixation of an osteochondral fracture of the patella. Copyright 2012, SLACK Incorporated.

  8. Potential pitfall in the microfracturing technique during the arthroscopic treatment of an osteochondral lesion

    NARCIS (Netherlands)

    van Bergen, C.J.A.; de Leeuw, P.A.J.; van Dijk, C.N.

    2009-01-01

    Debridement and bone marrow stimulation of the subchondral bone is currently considered to be the primary surgical treatment of most osteochondral lesions of the talus. Different methods of bone marrow stimulation are used, including drilling, abrasion, and microfracturing. The latter has gained

  9. Suitability of EGCG as a Means of Stabilizing a Porcine Osteochondral Xenograft.

    Science.gov (United States)

    Elder, Steven; Clune, John; Walker, Jaylyn; Gloth, Paul

    2017-09-23

    As a non-crosslinked osteochondral xenograft would be mechanically inferior to native cartilage and vulnerable to premature degradation, we seek a safe and effective method of xenograft stabilization. The purpose of this study was to evaluate the capacity for epigallocatechin gallate (EGCG) to stabilize a decellularized porcine osteochondral xenograft through collagen crosslinking. Our objectives were to assess the effects of EGCG on the degree of crosslinking, mechanical properties, collagenase resistance, cytotoxicity, and in vitro biocompatibility. EGCG is a green tea polyphenol that acts as a collagen crosslinker. Porcine osteochondral plugs were decellularized and then crosslinked by soaking in EGCG. The degree of crosslinking, cartilage compressive stiffness, cartilage-bone interface strength, coefficient of friction, and residual mass after collagenase exposure all increased with an increasing EGCG concentration. With the exception of the coefficient of friction, EGCG treatment could restore mechanical properties to levels equal to, or exceeding those, of native cartilage. EGCG treatment profoundly increased the enzymatic resistance, and 1% EGCG provided protection equivalent to 1% glutaraldehyde. EGCG up to 0.5 mM was essentially not cytotoxic to chondrocytes embedded in alginate, and autologous chondrocytes attached to decellularized, EGCG-fixed cartilage were all viable five days after seeding. Results demonstrate that EGCG has many beneficial effects on a decellularized osteochondral xenograft, and may be suitable for use in stabilizing such a graft prior to implantation for the repair of a defect.

  10. Bone shape difference between control and osteochondral defect groups of the ankle joint

    NARCIS (Netherlands)

    Tümer, N; Blankevoort, L; van de Giessen, M; Terra, M P; de Jong, P.A.; Weinans, H; Tuijthof, G J M; Zadpoor, A A

    2016-01-01

    OBJECTIVE: The etiology of osteochondral defects (OCDs), for which the ankle (talocrural) joint is one of the common sites, is not yet fully understood. In this study, we hypothesized that bone shape plays a role in development of OCDs. Therefore, we quantitatively compared the morphology of the

  11. Dual growth factor delivery from bilayered, biodegradable hydrogel composites for spatially-guided osteochondral tissue repair

    NARCIS (Netherlands)

    Lu, S.; Lam, J.; Trachtenberg, J.E.; Lee, E.J.; Seyednejad, H.; van den Beucken, J.J.; Tabata, Y.; Wong, M.E.; Jansen, J.A.; Mikos, A.G.; Kasper, F.K.

    2014-01-01

    The present work investigated the use of biodegradable hydrogel composite scaffolds, based on the macromer oligo(poly(ethylene glycol) fumarate) (OPF), to deliver growth factors for the repair of osteochondral tissue in a rabbit model. In particular, bilayered OPF composites were used to mimic the

  12. Fresh osteochondral knee allografts in Brazil with a minimum two-year follow-up

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    Luís Eduardo Passarelli Tírico

    Full Text Available ABSTRACT OBJECTIVE: The present study aimed to report the results of the first series of cases of fresh ostechondral allografts in the knee joint in Brazil with a minimum follow-up of two years. METHODS: A protocol of procurement, harvesting, processing, and utilization of fresh osteochondral allografts in the knee joint was established, beginning with legislation modifications, graft harvesting techniques, immediate processing, storage of fresh grafts, and utilization of two surgical techniques of osteochondral transplantation. Eight patients were treated and followed-up for a minimum of two years. RESULTS: Patients were evaluated with subjective IKDC, KOOS, and modified Merle D'Aubigne and Postel questionnaires. Mean subjective IKDC score was 31.99 ± 13.4 preoperative and 81.26 ± 14.7 at the latest follow-up; preoperative KOOS score was 46.8 ± 20.9 and postoperative was 85.24 ± 13.9, indicating a significant improvement over time (p < 0.01. Mean modified Merle D'Aubigne-Postel score was 8.75 ± 2.25, preoperatively, and 16.1 ± 2.59 postoperatively. Friedman test for non-parametric samples demonstrated a significant improvement in postoperative scores (p < 0.01. CONCLUSION: The use of fresh osteochondral allografts in Brazil is a safe procedure, with good clinical results in the short- and medium-term for the treatment of osteochondral lesions greater than 4 cm2 in the knee joint.

  13. Osteochondritis deformans juvenilis coxae ; ziekte van Legg-Calvé-Perthes

    NARCIS (Netherlands)

    Beeker, Theodorus Willem

    1965-01-01

    SAMENVATTING In deze dissertatie worden naar aanleiding van de resultaten van de behandeling van 55 patientjes, lijdende aan een osteochondritis deformans juvenilis coxae een aantal aspecten van deze ziekte nader in beschouwing genomen. In de inleiding (Hoofdstuk 1) wordt gewezen op de sterke mate,

  14. Effect of load on the repair of osteochondral defects using a porous polymer scaffold

    NARCIS (Netherlands)

    Hannink, G.; Mulder, E.L. de; Tienen, T.G. van; Buma, P.

    2012-01-01

    The aim of the present study was to evaluate if a porous polymer scaffold, currently used for partial meniscal replacement in clinical practice, could initiate regeneration and repair of osteochondral defects, and if regeneration and repair were related to mechanical stimulation. Two equally sized

  15. Immunogenicity of unprocessed and photooxidized bovine and human osteochondral grafts in collagen-sensitive mice

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    Lehmann Paul V

    2006-03-01

    Full Text Available Abstract Background Autologous and allogeneic osteochondral grafts have been used to repair damaged or diseased cartilage. There are drawbacks to both of these methods, however. Another possible source for osteochondral grafting is photooxidized xenograft scaffolds. The purpose of this study was to evaluate the adaptive immune response to unprocessed and photooxidized xenogeneic osteochondral grafts in a collagen-sensitive mouse model. Methods Unprocessed and photooxidized bovine and human osteochondral grafts were used. The grafts were implanted subcutaneously in collagen-sensitive DBA/1LacJ mice for four or twelve weeks. ELISPOT assays were conducted with spleen cells to evaluate the number of collagen-specific T cells that produce IL-2, IL-4, IL-5 or IFN-γ. Serum was collected and ELISA assays were performed to determine the titers of collagen-specific and total IgG, IgG1, IgG2a, or IgM antibodies. Histology was conducted on the retrieved osteochondral grafts. Results Results indicated that, with respect to adaptive T cell immunity, the photooxidized bovine grafts, unprocessed human grafts and photooxidized human grafts did not induce a significant response to collagen. The unprocessed bovine grafts, however, were slightly more immunogenic, inducing a weak immune response. With respect to antibody production, the bovine grafts were less immunogenic than the human grafts. Bovine collagen-specific IgG antibodies were not induced by these grafts, but production of IgM after twelve weeks was observed with both the unprocessed and photooxidized bovine grafts. In contrast, photooxidized human osteochondral grafts induced IgG1 and IgG2a antibodies, while the unprocessed human grafts did not. Pre-existing human collagen-specific IgM antibodies were present in all mice, including sham-operated negative controls that did not receive an implant. Histological analysis revealed some degree of fibrous encapsulation and inflammatory infiltrations in both

  16. Technical Report: Correlation Between the Repair of Cartilage and Subchondral Bone in an Osteochondral Defect Using Bilayered, Biodegradable Hydrogel Composites

    NARCIS (Netherlands)

    Lu, S.; Lam, J.; Trachtenberg, J.E.; Lee, E.J.; Seyednejad, H.; Beucken, J.J.J.P van den; Tabata, Y.; Kasper, F.K.; Scott, D.W.; Wong, M.E.; Jansen, J.A.; Mikos, A.G.

    2015-01-01

    The present work investigated correlations between cartilage and subchondral bone repair, facilitated by a growth factor-delivering scaffold, in a rabbit osteochondral defect model. Histological scoring indices and microcomputed tomography morphological parameters were used to evaluate cartilage and

  17. Custom-designed orthopedic implants evaluated using finite element analysis of patient-specific computed tomography data: femoral-component case study

    Directory of Open Access Journals (Sweden)

    Nayfeh Jamal F

    2007-09-01

    Full Text Available Abstract Background Conventional knee and hip implant systems have been in use for many years with good success. However, the custom design of implant components based on patient-specific anatomy has been attempted to overcome existing shortcomings of current designs. The longevity of cementless implant components is highly dependent on the initial fit between the bone surface and the implant. The bone-implant interface design has historically been limited by the surgical tools and cutting guides available; and the cost of fabricating custom-designed implant components has been prohibitive. Methods This paper describes an approach where the custom design is based on a Computed Tomography scan of the patient's joint. The proposed design will customize both the articulating surface and the bone-implant interface to address the most common problems found with conventional knee-implant components. Finite Element Analysis is used to evaluate and compare the proposed design of a custom femoral component with a conventional design. Results The proposed design shows a more even stress distribution on the bone-implant interface surface, which will reduce the uneven bone remodeling that can lead to premature loosening. Conclusion The proposed custom femoral component design has the following advantages compared with a conventional femoral component. (i Since the articulating surface closely mimics the shape of the distal femur, there is no need for resurfacing of the patella or gait change. (ii Owing to the resulting stress distribution, bone remodeling is even and the risk of premature loosening might be reduced. (iii Because the bone-implant interface can accommodate anatomical abnormalities at the distal femur, the need for surgical interventions and fitting of filler components is reduced. (iv Given that the bone-implant interface is customized, about 40% less bone must be removed. The primary disadvantages are the time and cost required for the

  18. Importance of Donor Chondrocyte Viability for Osteochondral Allografts.

    Science.gov (United States)

    Cook, James L; Stannard, James P; Stoker, Aaron M; Bozynski, Chantelle C; Kuroki, Keiichi; Cook, Cristi R; Pfeiffer, Ferris M

    2016-05-01

    Osteochondral allograft (OCA) transplantation provides a biological treatment option for functional restoration of large articular cartilage defects in multiple joints. While successful outcomes after OCA transplantation have been linked to viable donor chondrocytes, the importance of donor cell viability has not been comprehensively validated. To use a canine model to determine the importance of donor chondrocyte viability at the time of implantation with respect to functional success of femoral condylar OCAs based on radiographic, gross, cell viability, histologic, biochemical, and biomechanical outcome measures. Controlled laboratory study. After approval was obtained from the institutional animal care and use committee, adult female dogs (N = 16) were implanted with 8-mm cylindrical OCAs from male dogs in the lateral and medial femoral condyles of 1 knee. OCAs were preserved for 28 or 60 days after procurement, and chondrocyte viability was quantified before implantation. Two different storage media, temperatures, and time points were used to obtain a spectrum of percentage chondrocyte viability at the time of implantation. A successful outcome was defined as an OCA that was associated with graft integration, maintenance of hyaline cartilage, lack of associated cartilage disorder, and lack of fibrillation, fissuring, or fibrous tissue infiltration of the allograft based on subjective radiographic, gross, and histologic assessments at 6 months after implantation. Chondrocyte viability ranged from 23% to 99% at the time of implantation. All successful grafts had >70% chondrocyte viability at the time of implantation, and no graft with chondrocyte viability <70% was associated with a successful outcome. Live-dead stained sections and histologic findings with respect to cell morphological features suggested that successful grafts were consistently composed of viable chondrocytes in lacunae, while grafts that were not successful were composed of nonviable

  19. Platelet-Rich Plasma and Concentrated Bone Marrow Aspirate in Surgical Treatment for Osteochondral Lesions of the Talus.

    Science.gov (United States)

    Yasui, Youichi; Ross, Andrew W; Kennedy, John G

    2016-12-01

    Platelet-rich plasma (PRP) and concentrated bone marrow aspirate (CBMA) have the potential to improve the quality of cartilage repair in osteochondral lesions of the talus (OLT). In this review, we describe the basic science and clinical evidence that has been published on the topic of PRP and CBMA on 2 commonly used surgical techniques for the treatment of OLT: bone marrow stimulation and osteochondral autograft transfer. Copyright © 2016 Elsevier Inc. All rights reserved.

  20. Two Patients with Osteochondral Injury of the Weight-Bearing Portion of the Lateral Femoral Condyle Associated with Lateral Dislocation of the Patella

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    Shuji Nakagawa

    2014-01-01

    Full Text Available Complications of patellar dislocation include osteochondral injury of the lateral femoral condyle and patella. Most cases of osteochondral injury occur in the anterior region, which is the non-weight-bearing portion of the lateral femoral condyle. We describe two patients with osteochondral injury of the weight-bearing surface of the lateral femoral condyle associated with lateral dislocation of the patella. The patients were 18- and 11-year-old females. Osteochondral injury occurred on the weight-bearing surface distal to the lateral femoral condyle. The presence of a free osteochondral fragment and osteochondral injury of the lateral femoral condyle was confirmed on MRI and reconstruction CT scan. Treatment consisted of osteochondral fragment fixation or microfracture, as well as patellar stabilization. Osteochondral injury was present in the weight-bearing portion of the lateral femoral condyle in both patients, suggesting that the injury was caused by friction between the patella and lateral femoral condyle when the patella was dislocated or reduced at about 90° flexion of the knee joint. These findings indicate that patellar dislocation may occur and osteochondral injury may extend to the weight-bearing portion of the femur even in deep flexion, when the patella is stabilized on the bones of the femoral groove.

  1. Osteochondral graft from the pre-achilles area for replacement of articular surface defects

    Science.gov (United States)

    Kuznetsov, V. V.; Pahomov, I. A.; Prohorenko, V. M.; Sadovoy, M. A.; Korel, A. V.; Zaydman, A. M.; Repin, A. V.; Gudi, S. M.; Korochkin, S. B.

    2017-09-01

    We substantiate a new technique for obtaining osteochondral autograft to replace osteochondral defects resulting from various lesions of the talar trochlea by means of morphological examination of the following microslides: talar cartilage (cadaver material), cartilage portion of the pre-achilles zone of the calcaneum, lateral femoral condyle, and necrotic area of the talus. Examination of the specimens of the pre-achilles cartilage of the calcaneus revealed a large number of poorly differentiated chondroblasts in the homogeneously stained extracellular matrix; the presence of all zones (superficial zone, zone of columnar structures, and "tidemark"). This is indicative of structural and functional preservation of this cartilage, which therefore can be considered as an autograft material.

  2. Osteochondral lesions of the talus in the athlete: up to date review.

    Science.gov (United States)

    Shimozono, Yoshiharu; Yasui, Youichi; Ross, Andrew W; Kennedy, John G

    2017-03-01

    Osteochondral lesions of the talus (OLT) are common injuries in athletes. The purpose of this study is to comprehensively review the clinical results and return to sport capacity in athletes following treatment for OLT. Reparative procedures, such as bone marrow stimulation, and replacement procedures, such as autologous osteochondral transplantation, provide good clinical outcomes in short- and mid-term follow-up in the athlete. Recently, biological augmentation and scaffold-based therapies have been shown to improve clinical and radiological outcomes in OLT in both the general population and athletes. Most studies are of a low level of evidence. Studies analyzing the return to sport capability in athletes are further lacking. High-level evidence and well-designed clinical trials are required to establish the most effective treatment protocol.

  3. Variation of Mesenchymal Cells in Polylactic Acid Scaffold in an Osteochondral Repair Model

    Science.gov (United States)

    Oshima, Yasushi; Harwood, Frederick L.; Coutts, Richard D.; Kubo, Toshikazu

    2009-01-01

    Objective To achieve osteochondral regeneration utilizing transplantation of cartilage-lineage cells and adequate scaffolds, it is essential to characterize the behavior of transplanted cells in the repair process. The objectives of this study were to elucidate the survival of mesenchymal cells (MCs). In a polylactic acid (PLA) scaffold and assess the possibility of MC/PLA constructs for osteochondral repair. Design Bone marrow from mature male rabbits was cultured for 2 weeks, and fibroblast-like MCs, which contain mesenchymal stem cells (MSCs), were obtained. A cell/scaffold construct was prepared with one million MCs and a biodegradable PLA core using a rotator device. One week after culturing, the construct was transplanted into an osteochondral defect in the medial femoral condyle of female rabbits and the healing process examined histologically. To examine the survivability of transplanted MCs, the male-derived sex-determining region Y (SRY) gene was assessed as a marker of MCs in the defect by polymerase chain reaction (PCR). Results In the groups of defects without any treatment, and the transplantation of PLA without cells, the defects were not repaired with hyaline cartilage. The cartilaginous matrix by safranin O staining and type II collagen by immunohistochemical staining were recognized, however the PLA matrix was still present in the defects at 24 weeks after transplantation of the construct. During the time passage, transplanted MCs numbers decreased from 7.8 × 105 at 1 week, to 3.5 × 105 at 4 weeks, and to 3.8 × 104 at 12 weeks. Transplanted MCs were not detectable at 24 weeks. Conclusions MCs contribute to the osteochondral repair expressing the cartilaginous matrix, however the number of MCs were decreasing with time (i.e. 24 weeks). These results could be essential for achieving cartilage regeneration by cell transplantation strategies with growth factors and/or gene therapy. PMID:19231922

  4. Anconeus Muscle-Pedicle Bone Graft With Periosteal Coverage for Osteochondritis Dissecans of the Humeral Capitellum

    OpenAIRE

    Shimada, Kozo; Temporin, Ko; Oura, Keiichiro; Tanaka, Hiroyuki; Noguchi, Ryosuke

    2017-01-01

    Background: Treatment of advanced osteochondritis dissecans (OCD) of the capitellum is controversial, especially in moderate-sized lesions. Purpose: To establish a treatment algorithm for capitellum OCD, we tried to determine the utility of and problems associated with anconeus muscle-pedicle bone graft with periosteal coverage (ABGP) for the treatment of moderate-sized articular OCD defects of the capitellum. Study Design: Case series; Level of evidence, 4. Methods: According to our protocol...

  5. Treatment of osteochondral fractures of the knee: a meta-analysis of available scientific evidence.

    Science.gov (United States)

    Kühle, Jan; Angele, Peter; Balcarek, Peter; Eichinger, Martin; Feucht, Matthias; Haasper, Carl; Alexander, Gohm; Jung, Tobias; Lill, Helmut; Marquass, Bastian; Osti, Michael; Rosenberger, Ralf; Salzmann, Gian; Steinwachs, Matthias; Voigt, Christine; Vogt, Stephan; Zeichen, Johannes; Niemeyer, Philipp

    2013-12-01

    Although traumatic osteochondral fractures of the knee represent a common pathology of the knee joint, there is no general agreement concerning specific treatment of this entity. This meta-analysis was initiated in order to evaluate scientific evidence on different treatment options for acute osteochondral fractures of the knee. For this purpose an OVID-based systematic literature search was performed including the following databases: MEDLINE, MEDLINE preprints, Embase, CINAHL, Life Science Citations, British National Library of Health and Cochrane Central Register of Controlled Trials. The literature search period was from 1946 to January 2012, which led to the identification of 1,226 articles. After applying study-specific inclusion criteria a total of 19 studies with clinical follow-up of 638 patients were included. The methodology of these studies was systematically analysed by means of the Coleman Methodology Score. Outcome and success rates were evaluated depending on treatment applied. All studies (n = 19) identified represent case series (evidence-based medicine level IV) and included a total of 638 patients. The average post-operative follow-up was 46 ± 27 months (range 3.75-108). The mean number of study subjects per study was 33 ± 44 patients (range 4-169). The average Coleman Methodology Score was 29 ± 17 points (range 5-72). Six different scoring systems were used for clinical assessment. The overall clinical success rate was 83% and varied between 45 and 100%. This meta-analysis reveals a significant lack of scientific evidence for treatment of osteochondral fractures of the knee. No valid conclusion can be drawn from this study concerning the recommendation of a specific treatment algorithm. Nevertheless, the overall failure rate of 17% underlines that an acute osteochondral fracture of the knee represents an important pathology which is not a self-limiting injury and needs further investigation.

  6. Long term in-vivo studies of a photo-oxidized bovine osteochondral transplant in sheep

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    Zlinszky Kati

    2001-11-01

    Full Text Available Abstract Background Articular cartilage has limited capacity to repair. Defects greater than 3 mm heal with formation of inferior fibrous cartilage. Therefore, many attempts have been made to find the ideal graft for larger cartilage lesions. Different grafts, such as untreated or cryopreserved osteochondral transplants, have been used with variable success. Methods Photo-oxidized osteochondral grafts were implanted in both femoral condyles of one ovine knee. Untreated xenogeneic and autogeneic grafts served as controls. Three groups of 8 sheep each were formed and they were sacrificed 6, 12 or 18 months after surgery. Results The macroscopic evaluation of the condyle and graft showed a well-maintained cartilage surface in most grafts at all time points. However, the host cartilage matrix deteriorated considerably in all xenogeneic, most autogeneic and fewer of the photo-oxidized grafts at 12 and 18 months, respectively. The blue colour of the photo-oxidized grafts resulting from the process of photo-oxidation was visible in all grafts at 6 months, had diminished at 12 months and had completely disappeared at 18 months after surgery. Histologically a loss of matrix staining was almost never noticed in untreated xenografts, transiently at 6 months in photo-oxidized grafts and increased at 12 and 18 months. Fusion between graft and host cartilage could be seen in photo-oxidized grafts at 12 and 18 months, but was never seen in autografts and xenografts. Conclusions The photo-oxidation of osteochondral grafts and its use as transplant appears to have a beneficial effect on cartilage and bone remodelling. Osteochondral grafts pre-treated with photo-oxidation may be considered for articular cartilage replacement and therefore may delay artificial joint replacements in human patients.

  7. Anatomical Glenoid Reconstruction Using Fresh Osteochondral Distal Tibia Allograft After Failed Latarjet Procedure

    OpenAIRE

    Sanchez, Anthony; Ferrari, Marcio B.; Akamefula, Ramesses A.; Frank, Rachel M.; Sanchez, George; Provencher, Matthew T.

    2017-01-01

    In the treatment of recurrent anterior glenohumeral instability, the Latarjet procedure has been shown to fail. This results in a need for viable revisional procedures for patients who present with this challenging pathology. We report our preferred technique for anatomical glenoid reconstruction using a fresh osteochondral distal tibia allograft after a failed Latarjet procedure. This bony augmentation technique employs a readily available dense, weight-bearing osseous tissue source that has...

  8. Biomechanical Evaluation of Spontaneity Repair of Osteochondral Defects in Rabbit Knee

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    Fahimeh Kamali

    2007-01-01

    Full Text Available Objective: Full-thickness defects measuring 3 mm in diameter have been commonly used in studies of rabbits to evaluate new procedures designed to improve the quality of articular cartilage repair. These defects initially heal spontaneously. However, little information is available on the characteristics of repair of large defects. The aim of present study was to define the biomechanical characteristics of repair of 5x4 mm full- thickness osteochondral defects in the adolescent male rabbit. Materials & Methods: In a Quasi - Experimental study 5 millimeter diameter and 4 mm deep osteochondral defects were drilled in femoral patellar groove of twenty-one rabbits , and examined at 4 ,8 and 16 weeks. The left knee was kept intact as the normal control. . The knee joints were removed, and both legs were examined biomechanically by in situ indentation method at three time- intervals (4, 8, 16 weeks. The instantaneous and equilibrium elastic- modulus (after 900 second measured during the test. Results: There were no differences in cartilage mechanical properties (instantaneous and equilibrium elastic- modulus between weeks (4, 8, 16 weeks in two groups (P>0/05. Although Significant differences between experimental and control groups were seen in 16 weeks in instantaneous elastic- modulus (P<0/05. New tissue supported high stiffness than normal control in 16 weeks. Conclusion: Full-thickness osteochondral defects, measuring 5x4 mm in diameter and dept in patellar groove of adolescent rabbit knee heal spontaneously.

  9. Arthroscopic retrograde osteochondral autologous transplantation to chondral lesion in femoral head.

    Science.gov (United States)

    Cetinkaya, Sarper; Toker, Berkin; Taser, Omer

    2014-06-01

    This report describes the treatment of 2 cases of full-thickness cartilage defect of the femoral head. The authors performed osteochondral autologous transplantation with a different technique that has not been reported to date. One patient was 37 years old, and the other was 42 years old. Both presented with hip pain. In both patients, radiograph and magnetic resonance imaging scan showed a focal chondral defect on the weight-bearing area of the femoral head and acetabular impingement. A retrograde osteochondral autologous transplantation technique combined with hip arthroscopy and arthroscopic impingement treatment was performed. After a 2-month recovery period, the symptoms were resolved. In the first year of follow-up, Harris Hip scores improved significantly (case 1, 56.6 to 87.6; case 2, 58.6 to 90). The technique described yielded good short- and midterm clinical and radiologic outcomes. To the authors' knowledge, this report is the first to describe a retrograde osteochondral transplantation technique performed with hip arthroscopy in the femoral head. Copyright 2014, SLACK Incorporated.

  10. 3D Printing and Biofabrication for Load Bearing Tissue Engineering.

    Science.gov (United States)

    Jeong, Claire G; Atala, Anthony

    2015-01-01

    Cell-based direct biofabrication and 3D bioprinting is becoming a dominant technological platform and is suggested as a new paradigm for twenty-first century tissue engineering. These techniques may be our next step in surpassing the hurdles and limitations of conventional scaffold-based tissue engineering, and may offer the industrial potential of tissue engineered products especially for load bearing tissues. Here we present a topically focused review regarding the fundamental concepts, state of the art, and perspectives of this new technology and field of biofabrication and 3D bioprinting, specifically focused on tissue engineering of load bearing tissues such as bone, cartilage, osteochondral and dental tissue engineering.

  11. Technical Report: Correlation Between the Repair of Cartilage and Subchondral Bone in an Osteochondral Defect Using Bilayered, Biodegradable Hydrogel Composites.

    Science.gov (United States)

    Lu, Steven; Lam, Johnny; Trachtenberg, Jordan E; Lee, Esther J; Seyednejad, Hajar; van den Beucken, Jeroen J J P; Tabata, Yasuhiko; Kasper, F Kurtis; Scott, David W; Wong, Mark E; Jansen, John A; Mikos, Antonios G

    2015-12-01

    The present work investigated correlations between cartilage and subchondral bone repair, facilitated by a growth factor-delivering scaffold, in a rabbit osteochondral defect model. Histological scoring indices and microcomputed tomography morphological parameters were used to evaluate cartilage and bone repair, respectively, at 6 and 12 weeks. Correlation analysis revealed significant associations between specific cartilage indices and subchondral bone parameters that varied with location in the defect (cortical vs. trabecular region), time point (6 vs. 12 weeks), and experimental group (insulin-like growth factor-1 only, bone morphogenetic protein-2 only, or both growth factors). In particular, significant correlations consistently existed between cartilage surface regularity and bone quantity parameters. Overall, correlation analysis between cartilage and bone repair provided a fuller understanding of osteochondral repair and can help drive informed studies for future osteochondral regeneration strategies.

  12. Validation and Application of a Custom-Designed Targeted Next-Generation Sequencing Panel for the Diagnostic Mutational Profiling of Solid Tumors.

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    Guy Froyen

    Full Text Available The inevitable switch from standard molecular methods to next-generation sequencing for the molecular profiling of tumors is challenging for most diagnostic laboratories. However, fixed validation criteria for diagnostic accreditation are not in place because of the great variability in methods and aims. Here, we describe the validation of a custom panel of hotspots in 24 genes for the detection of somatic mutations in non-small cell lung carcinoma, colorectal carcinoma and malignant melanoma starting from FFPE sections, using 14, 36 and 5 cases, respectively. The targeted hotspots were selected for their present or future clinical relevance in solid tumor types. The target regions were enriched with the TruSeq approach starting from limited amounts of DNA. Cost effective sequencing of 12 pooled libraries was done using a micro flow cell on the MiSeq and subsequent data analysis with MiSeqReporter and VariantStudio. The entire workflow was diagnostically validated showing a robust performance with maximal sensitivity and specificity using as thresholds a variant allele frequency >5% and a minimal amplicon coverage of 300. We implemented this method through the analysis of 150 routine diagnostic samples and identified clinically relevant mutations in 16 genes including KRAS (32%, TP53 (32%, BRAF (12%, APC (11%, EGFR (8% and NRAS (5%. Importantly, the highest success rate was obtained when using also the low quality DNA samples. In conclusion, we provide a workflow for the validation of targeted NGS by a custom-designed pan-solid tumor panel in a molecular diagnostic lab and demonstrate its robustness in a clinical setting.

  13. Return to running following knee osteochondral repair using an anti-gravity treadmill: A case report.

    Science.gov (United States)

    Hambly, Karen; Poomsalood, Somruthai; Mundy, Emma

    2017-07-01

    The purpose of this study was to assess the impact of an anti-gravity treadmill return to running programme on self-efficacy and subjective knee function following knee osteochondral surgery. A 39-year-old otherwise healthy female endurance runner with a left knee femoral cartilage grade 3-4 defect 3 cm2. The patient underwent single step arthroscopic microfracture with Bone Marrow Aspirate Concentrate. An AlterG® anti-gravity treadmill was used to manipulate loading during a graduated phased return to running over 8 weeks. Self-efficacy was evaluated using the Self-Efficacy for Rehabilitation outcomes scale (SER) and the Knee Self-Efficacy Scale (K-SES). Subjective knee function was evaluated using the Knee injury and Osteoarthritis Outcome Score (KOOS) and International Knee Documentation Committee Subjective Knee Form (IKDC). The programme resulted in improvements in SER (57%), K-SES present (89%) and K-SES future (65%) self-efficacy domains. The IKDC score demonstrated a clinically important improvement with an increase from 62.1 in week 1-86.2 in week 8 (39%). Only the KOOS Sport/Rec subscale showed a clinically important improvement from week 1 to week 8. The programme resulted in improved knee and rehabilitation self-efficacy and subjective knee function following osteochondral repair of the knee. This case report illustrates the importance of considering self-efficacy in rehabilitation after knee osteochondral surgery and highlights the potential role for anti-gravity treadmills in enhancing self-efficacy and subjective knee function in preparation for a return to sport. Crown Copyright © 2017. Published by Elsevier Ltd. All rights reserved.

  14. Cylindrical press-fit osteochondral allografts for resurfacing the equine metatarsophalangeal joint.

    Science.gov (United States)

    Pearce, Simon G; Hurtig, Mark B; Boure, Ludovic P; Radcliffe, Rolfe M; Richardson, Dean W

    2003-01-01

    To investigate the feasibility of resurfacing the equine fetlock joint using cylindrical, orthotopic, press-fit, osteochondral allografts. Experimental study. Ten mature, mixed-breed horses. Cylindrical, osteochondral grafts (6.5-mm diameter) were harvested aseptically from cadaveric equine metatarsophalangeal joints. Allografts were transplanted into 6 horses; 4 horses were sham operated. The surgical approach involved creation of a bone block at the origin of the medial collateral ligament and luxation of the metatarsophalangeal joint. Grafts were placed into the medial and lateral metatarsal condyles. Radiographs were taken at 8 and 25 weeks, and lameness was evaluated at 25 weeks. Horses were killed at 25 weeks. Analyses included gross evaluation, microradiography, paravital staining, light microscopy, and cartilage biochemistry. No complications occurred that could be attributed to the surgical procedure. Graft congruency with the surrounding articular cartilage was fair to excellent. Two horses were sound at 25 weeks. Most grafts had more than 90% articular cartilage coverage, and histologic and microradiographic analysis revealed good graft incorporation and articular cartilage survival. Sulphated glycosaminoglycan concentration was decreased in grafted tissue. We attribute the viability of osteochondral allografts in the equine fetlock to adequate congruency, stable graft fixation, and the use of orthotopic tissue. Host response to the allograft bone tissue did not affect cartilage viability. Before clinical use, improvements to instrumentation are required that would decrease damage to grafts and minimize technique-associated incongruencies of the articular surface at the time of grafting. Larger grafts would also likely be required to resurface a greater surface area. Copyright 2003 by The American College of Veterinary Surgeons

  15. Osteochondral tissue regeneration through polymeric delivery of DNA encoding for the SOX trio and RUNX2.

    Science.gov (United States)

    Needham, Clark J; Shah, Sarita R; Dahlin, Rebecca L; Kinard, Lucas A; Lam, Johnny; Watson, Brendan M; Lu, Steven; Kasper, F Kurtis; Mikos, Antonios G

    2014-10-01

    Native osteochondral repair is often inadequate owing to the inherent properties of the tissue, and current clinical repair strategies can result in healing with a limited lifespan and donor site morbidity. This work investigates the use of polymeric gene therapy to address this problem by delivering DNA encoding for transcription factors complexed with the branched poly(ethylenimine)-hyaluronic acid (bPEI-HA) delivery vector via a porous oligo[poly(ethylene glycol) fumarate] hydrogel scaffold. To evaluate the potential of this approach, a bilayered scaffold mimicking native osteochondral tissue organization was loaded with DNA/bPEI-HA complexes. Next, bilayered implants either unloaded or loaded in a spatial fashion with bPEI-HA and DNA encoding for either Runt-related transcription factor 2 (RUNX2) or SRY (sex determining region Y)-box 5, 6, and 9 (the SOX trio), to generate bone and cartilage tissues respectively, were fabricated and implanted in a rat osteochondral defect. At 6weeks post-implantation, micro-computed tomography analysis and histological scoring were performed on the explants to evaluate the quality and quantity of tissue repair in each group. The incorporation of DNA encoding for RUNX2 in the bone layer of these scaffolds significantly increased bone growth. Additionally, a spatially loaded combination of RUNX2 and SOX trio DNA loading significantly improved healing relative to empty hydrogels or either factor alone. Finally, the results of this study suggest that subchondral bone formation is necessary for correct cartilage healing. Copyright © 2014 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  16. The effects of low-dose radiotherapy on fresh osteochondral allografts: An experimental study in rabbits.

    Science.gov (United States)

    Gönç, Uğur; Çetinkaya, Mehmet; Atabek, Mesut

    2016-10-01

    The aim of this study was to investigate the effects of low-dose fractionated radiotherapy on cartilage degeneration after distal femoral fresh massive osteochondral allograft transplantation. Twenty-four New Zealand White rabbits were divided into three groups of 8 rabbits each. All rabbits underwent distal femoral medial condyle fresh massive osteochondral allograft transplantation from California rabbits. The group 1 underwent transplantation without any preliminary process. The group 2 underwent fractionated local radiotherapy of 100 cGy for five days starting on the transplantation day. The group 3 included the rabbits to which the grafts transplanted after radiating in vitro by a single dose radiation of 1500 cGy. The hosts were sacrificed twelve weeks later. Anteroposterior and lateral radiographs were taken. Synovial tissue, cartilaginous tissue, and subchondral bone were assessed histopathologically. Nonunion was present in three cases of group 2 and one of group 3 in which cartilage degeneration was more severe. Synovial hypertrophy and pannus formation were more obvious in non-radiated rabbits. Hypocellularity and necrosis of the subchondral bone were rare in group 2. More cartilage tissue impairment was present in group 3 compared to group 1. In osteochondral massive allograft transplantations, the immune reaction of the host could be precluded with radiotherapy, and the side-effects can be prevented by low-dose fractionated regimen. The total dose of fractionated radiotherapy for an immune suppression should be adjusted not to damage the cartilage tissue, but to avoid articular degeneration in the long term. Copyright © 2016 Turkish Association of Orthopaedics and Traumatology. Production and hosting by Elsevier B.V. All rights reserved.

  17. Anatomical Glenoid Reconstruction Using Fresh Osteochondral Distal Tibia Allograft After Failed Latarjet Procedure.

    Science.gov (United States)

    Sanchez, Anthony; Ferrari, Marcio B; Akamefula, Ramesses A; Frank, Rachel M; Sanchez, George; Provencher, Matthew T

    2017-04-01

    In the treatment of recurrent anterior glenohumeral instability, the Latarjet procedure has been shown to fail. This results in a need for viable revisional procedures for patients who present with this challenging pathology. We report our preferred technique for anatomical glenoid reconstruction using a fresh osteochondral distal tibia allograft after a failed Latarjet procedure. This bony augmentation technique employs a readily available dense, weight-bearing osseous tissue source that has excellent conformity, as well as the added benefit of a cartilaginous surface to correct chondral deficiencies. Given its effectiveness in the Latarjet revision setting and low complication rate, the distal tibia allograft is a reasonable treatment option.

  18. An Unexpected Complication after Headless Compression Screw Fixation of an Osteochondral Fracture of Patella

    Directory of Open Access Journals (Sweden)

    Suavi Aydoğmuş

    2016-01-01

    Full Text Available This study evaluated complications associated with implant depth in headless compression screw treatment of an osteochondral fracture associated with a traumatic patellar dislocation in a 21-year-old woman. Computed tomography and X-rays showed one lateral fracture fragment measuring 25 × 16 mm. Osteosynthesis was performed with two headless compression screws. Five months later, the screws were removed because of patella-femoral implant friction. We recommend that the screw heads be embedded to a depth of at least 3 mm below the cartilage surface. Further clinical studies need to examine the variation in cartilage thickness in the fracture fragment.

  19. Osteochondritis Dissecans of the Capitellum: A Case Report of Successful Arthroscopic Treatment

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    J. Ribeiras Cabral

    2017-01-01

    Full Text Available Introduction. Osteochondritis dissecans (OCD of the capitellum is a localized disorder of the subchondral bone, in a region with limited healing capacity. Although its aetiology is still unknown, it has been associated with repetitive microtrauma. The natural history of this disease involves the evolution for degenerative joint disease in approximately half of the patients, with early identification and treatment being critical to optimizing the outcome. Case Presentation. We present a rare case in our practice, illustrating a capitellar OCD in a fifteen-year-old White male without an identified cause of repetitive microtrauma. Conclusion. In this case prompt diagnosis and arthroscopic-assisted treatment led to a successful result.

  20. Foal Fractures: Osteochondral Fragmentation, Proximal Sesamoid Bone Fractures/Sesamoiditis, and Distal Phalanx Fractures.

    Science.gov (United States)

    Reesink, Heidi L

    2017-08-01

    Foals are susceptible to many of the same types of fractures as adult horses, often secondary to external sources of trauma. In addition, some types of fractures are specific to foals and occur routinely in horses under 1 year of age. These foal-specific fractures may be due to the unique musculoskeletal properties of the developing animal and may present with distinct clinical signs. Treatment plans and prognoses are tailored specifically to young animals. Common fractures not affecting the long bones in foals are discussed in this article, including osteochondral fragmentation, proximal sesamoid bone fractures/sesamoiditis, and distal phalanx fractures. Copyright © 2017 Elsevier Inc. All rights reserved.

  1. Chondrocyte death associated with human femoral osteochondral harvest as performed for mosaicplasty.

    Science.gov (United States)

    Huntley, J S; Bush, P G; McBirnie, J M; Simpson, A H; Hall, A C

    2005-02-01

    Autologous osteochondral transfer is an option for the treatment of articular defects. However, there are concerns about graft integration and the nature of the tissue forming the cartilage-cartilage bridge. Chondrocyte viability at graft and recipient edges is thought to be an important determinant of the quality of repair. The purpose of the present study was to evaluate early cell viability at the edges of osteochondral grafts from ex vivo human femoral condyles. Fresh human tissue was obtained from eleven knees at the time of total knee arthroplasty for the treatment of osteoarthritis. Osteochondral cylinders were harvested with use of a 4.5-mm-diameter mosaicplasty osteotome from regions of the anterolateral aspect of the femoral condyle that were macroscopically nondegenerate and histologically nonfibrillated. Plugs were assessed for marginal cell viability by means of confocal laser scanning microscopy. The diameter of the cartilaginous portion of the osteochondral plugs was a mean (and standard error of the mean) of 4.84 +/- 0.12 mm (as determined on the basis of three plugs). This value was approximately 300 microm greater than the measured internal diameter of the osteotome. There was a substantial margin of superficial zone cell death (mean thickness, 382 +/- 68.2 microm), with >99% cell viability seen more centrally (as determined on the basis of five plugs). Demiplugs were created by splitting the mosaicplasty explants with a fresh number-11 scalpel blade. The margin of superficial zone cell death at the curved edge was significantly greater than that at the site of the scalpel cut (390.3 +/- 18.8 microm compared with 34.8 +/- 3.2 microm; p = 0.0286). Similar findings were observed when the cartilage alone was breached and the bone was left intact, with the margin of superficial zone cell death being significantly greater than that obtained in association with the straight scalpel incision (268 +/- 38.9 microm compared with 41.3 +/- 13.4 microm; p = 0

  2. A minimal common osteochondrocytic differentiation medium for the osteogenic and chondrogenic differentiation of bone marrow stromal cells in the construction of osteochondral graft.

    Science.gov (United States)

    Li, Jian; Mareddy, Shobha; Tan, Dawn Meifang; Crawford, Ross; Long, Xing; Miao, Xigeng; Xiao, Yin

    2009-09-01

    To regenerate the complex tissue such as bone-cartilage construct using tissue engineering approach, controllable differentiation of bone marrow stromal cells (BMSCs) into chondrogenic and osteogenic lineages is crucially important. This study proposes to test a minimum common osteochondrocytic differentiation medium (MCDM) formulated by including common soluble supplements (dexamethasone and ascorbic acid) used to induce chondrogenic and osteogenic differentiation. The MCDM coupled with supplemented growth factors was tested for its ability to differentiate BMSCs into osteogenic and chondrogenic lineages in both two-dimensional and three-dimensional culture systems. When transforming growth factor beta3 was added to MCDM, BMSCs differentiated to chondrocyte-like cells, evidenced by the expression of glycosaminoglycans and type II collagen, whereas osteogenic differentiation was induced by supplementing osteogenic protein-1, resulting in detectable expression of osteopontin and osteocalcin. These chondrogenic and osteogenic differentiation markers were significantly enhanced in the three-dimensional cultures compared to the two-dimensional monolayer cultures. The results achieved in this study lay a foundation for future development of osteochondral graft, which could be engineered from bilayered scaffold with spatially loaded growth factors to control BMSC differentiation.

  3. Bioabsorbable Pins for Treatment of Osteochondral Fractures of the Knee after Acute Patella Dislocation in Children and Young Adolescents

    Directory of Open Access Journals (Sweden)

    A. Gkiokas

    2012-01-01

    Full Text Available A retrospective study was performed on the use of bioabsorbable pins in the fixation of osteochondral fractures (OCFs after traumatic patellar dislocation in children. Eighteen children (13 females, 5 males aged 11 to 15 years (mean age 13.1 years with osteochondral fracture (OCF of the knee joint were treated at the authors’ institution. Followup ranged from 22 months to 5 years. Diagnosis was verified by X-ray and magnetic resonance imaging (MRI of the knee and patella. In seven patients the osteochondral fragment was detached from the patella and in 11 it was detached from the lateral femoral condyle. All patients were subjected to open reduction and fixation of the lesion with bioabsorbable pins. Postoperatively, the knee was immobilized in a cast and all patients were mobilized applying a standardized protocol. Bone consolidation was successful in 17 of the 18 patients. Bioabsorbable pins reliably fix OCF in children and adolescents, demonstrating a high incidence of consolidation of the detached osteochondral fragment in short- and middle-term followup without requiring further operative procedures.

  4. Should in the treatment of osteochondritis dissecans biodegradable or metallic fixation devices be used? A comparative study in goat knees

    NARCIS (Netherlands)

    Wouters, Diederick B.; Bos, Rudolf R. M.; van Horn, Jim R.; van Luyn, Marja J. A.

    Most of the metallic devices have to be removed, treating osteochondritis dissecans lesions. This animal study describes the biological and mechanical behavior of screws and pins, made of commercially available PGA/PLA and PLA96 and metallic screws and pins, used for fragment fixation. A sham

  5. PEOT/PBT based scaffolds with low mechanical properties improve cartilage repair tissue formation in osteochondral defects

    NARCIS (Netherlands)

    Jansen, Edwin J. P.; Pieper, Jeroen; Gijbels, Marion J. J.; Guldemond, Nick A.; Riesle, Jens; Van Rhijn, Lodewijk W.; Bulstra, Sjoerd K.; Kuijer, Roel

    The aim of our Study was to compare the healing response of biomechanically and biochemically different scaffolds in osteochondral defects created in rabbit medial femoral condyles. A block copolymer comprised of poly(ethylene oxide terephthalate) and poly(butylene terephthalate) was used to prepare

  6. Treatment of severe osteochondral defects of the knee by combined autologous bone grafting and autologous chondrocyte implantation using fibrin gel

    NARCIS (Netherlands)

    Konst, Y.E.; Benink, R.J.; Veldstra, R.; van der Krieke, T.J.; Helder, M.N.; van Royen, B.J.

    2012-01-01

    Purpose: Severe symptomatic and unstable osteochondral defects of the knee are difficult to treat. A variety of surgical techniques have been developed. However, the optimal surgical technique is still controversial. We present a novel technique in which autologous bone grafting is combined with

  7. Incidence of symptomatic osteochondritis dissecans lesions of the knee : A population-based study in Olmsted County

    NARCIS (Netherlands)

    Pareek, A.; Sanders, T. L.; Wu, I. T.; Larson, D. R.; Saris, D. B.F.; Krych, A.J.

    2017-01-01

    Objective: To (1) define population-based incidence of knee Osteochondritis dissecans (OCD) lesions using the population of Olmsted County, (2) examine trends over time, and (3) evaluate rate of surgical management over time. Method: Study population included 302 individuals who were diagnosed with

  8. Osteochondral tissue regeneration using a bilayered composite hydrogel with modulating dual growth factor release kinetics in a rabbit model

    NARCIS (Netherlands)

    Kim, K.; Lam, J.; Lu, S.; Spicer, P.P.; Lueckgen, A.; Tabata, Y.; Wong, M.E.; Jansen, J.A.; Mikos, A.G.; Kasper, F.K.

    2013-01-01

    Biodegradable oligo(poly(ethylene glycol) fumarate) (OPF) composite hydrogels have been investigated for the delivery of growth factors (GFs) with the aid of gelatin microparticles (GMPs) and stem cell populations for osteochondral tissue regeneration. In this study, a bilayered OPF composite

  9. Repair of osteochondral defects with biodegradable hydrogel composites encapsulating marrow mesenchymal stem cells in a rabbit model.

    NARCIS (Netherlands)

    Guo, X.; Park, H.; Young, S.; Kretlow, J.D.; Beucken, J.J.J.P. van den; Baggett, L.S.; Tabata, Y.; Kasper, F.K.; Mikos, A.G.; Jansen, J.A.

    2010-01-01

    This work investigated the delivery of marrow mesenchymal stem cells (MSCs), with or without the growth factor transforming growth factor-beta1 (TGF-beta1), from biodegradable hydrogel composites on the repair of osteochondral defects in a rabbit model. Three formulations of oligo(poly(ethylene

  10. Influence of basal support and early loading on bone cartilage healing in press-fitted osteochondral autografts.

    Science.gov (United States)

    Nosewicz, Tomasz L; Reilingh, Mikel L; Wolny, Martin; van Dijk, C Niek; Duda, Georg N; Schell, Hanna

    2014-06-01

    The influence of basal graft support combined to early loading following an osteochondral autograft procedure is unclear. It was hypothesized that bottomed grafts may allow for early mobilization by preventing graft subsidence and leading to better healing. Osteochondral autografts were press fitted in the femoral condyles of 24 sheep (one graft per animal). In the unbottomed group (n = 12), a gap of 2 mm was created between graft and recipient bone base. In the bottomed group (n = 12), the graft firmly rested on recipient bone. Animals were allowed immediate postoperative weightbearing. Healing times were 3 and 6 months per group (n = 6 per subgroup). After killing, histological and histomorphometric analyses were performed. Unbottomed grafts at 3 months showed significantly more graft subsidence (P = 0.024), significantly less mineralized bone (P = 0.028) and significantly worse cartilage and subchondral bone plate healing (P = 0.034) when compared to bottomed grafts. At 6 months, no differences were seen. Compared to the native situation, unbottomed grafts showed significantly more graft subsidence (P = 0.024), whereas bottomed grafts did not. Cystic lesions were seen in both groups. Osteoclasts were closely related to the degree of bone remodelling. In the animal model, in the case of early loading, bottomed osteochondral autografts have less chance of graft subsidence. Evident subsidence negatively influences the histological healing process. In the osteochondral autograft procedure, full graft support should be aimed for. This may allow for early mobilization, diminish graft subsidence and improve long-term integration.

  11. Pulsed electromagnetic fields after arthroscopic treatment for osteochondral defects of the talus: double-blind randomized controlled multicenter trial

    NARCIS (Netherlands)

    van Bergen, Christiaan J. A.; Blankevoort, Leendert; de Haan, Rob J.; Sierevelt, Inger N.; Meuffels, Duncan E.; d'Hooghe, Pieter R. N.; Krips, Rover; van Damme, Geert; van Dijk, C. Niek

    2009-01-01

    ABSTRACT: BACKGROUND: Osteochondral talar defects usually affect athletic patients. The primary surgical treatment consists of arthroscopic debridement and microfracturing. Although this is mostly successful, early sport resumption is difficult to achieve, and it can take up to one year to obtain

  12. Pulsed electromagnetic fields after arthroscopic treatment for osteochondral defects of the talus: Double-blind randomized controlled multicenter trial

    NARCIS (Netherlands)

    C.J.A. van Bergen (Christiaan); L. Blankevoort (Leendert); R.J. de Haan (Rob); I.N. Sierevelt (Inger); D.E. Meuffels (Duncan); P.R.N. D'Hooghe (Pieter); R. Krips (Rover); G. van Damme (Geert); C.N. van Dijk (Niek)

    2009-01-01

    textabstractBackground. Osteochondral talar defects usually affect athletic patients. The primary surgical treatment consists of arthroscopic debridement and microfracturing. Although this is mostly successful, early sport resumption is difficult to achieve, and it can take up to one year to obtain

  13. The subchondral bone healing after fixation of an osteochondral talar defect is superior in comparison with microfracture

    NARCIS (Netherlands)

    Reilingh, Mikel L.; Lambers, Kaj T. A.; Dahmen, Jari; Opdam, Kim T. M.; Kerkhoffs, Gino M. M. J.

    2017-01-01

    Arthroscopic bone marrow stimulation (BMS) has been considered the primary surgical treatment for osteochondral defects (OCDs) of the talus. However, fixation has been considered as a good alternative. Recently, a new arthroscopic fixation technique was described: the lift, drill, fill and fix

  14. [Healing of osteochondral defects in canine knee with avocado/soybean unsaponifiables: a morphometric comparative analysis].

    Science.gov (United States)

    Altınel, Levent; Sahin, Onder; Köse, Kamil Cağrı; Baş, Orhan; Ozen, Oğuz Aslan; Sarıtaş, Z Kadir; Pamuk, Kamuran

    2011-01-01

    This study aims to determine the effects of avocado/soybean unsaponifiables (ASU) on healing in a canine osteochondral defect model. Fourteen dogs were included in the study and randomly divided into two groups. Two osteochondral defects were produced in the lateral aspect of the trochlear groove of the knee joint. The treatment group (group 1; n=7) was given 300 mg ASU capsules every three days whereas the control group (group 2; n=7) was given a normal diet. Animals were then allowed to ambulate normally until euthanasia at 15 weeks. The knees were dissected and the trochlear grooves with defects were removed for pathological examination. The amount of regenerated tissue was determined quantitatively using image analysis and the tissue content was evaluated semi-quantitatively using Safranin-O and Masson trichrome histochemical stains. Transforming growth factor beta (TGF-beta) increase was evaluated semi-quantitatively with immunohistochemical staining methods. Morphometric analysis revealed a significantly more immature repair tissue in group 1 (pcanine knee possibly by increasing TGF-beta in the tissues.

  15. Cell-laden biphasic scaffolds with anisotropic structure for the regeneration of osteochondral tissue.

    Science.gov (United States)

    Schütz, Kathleen; Despang, Florian; Lode, Anja; Gelinsky, Michael

    2016-05-01

    Sufficient treatment of chondral and osteochondral defects to restore function of the respective tissue remains challenging in regenerative medicine. Biphasic scaffolds that mimic properties of bone and cartilage are appropriate to regenerate both tissues at the same time. The present study describes the development of biphasic, but monolithic scaffolds based on alginate, which are suitable for embedding of living cells in the chondral part. Scaffolds are fabricated under sterile and cell-compatible conditions according to the principle of diffusion-controlled, directed ionotropic gelation, which leads to the formation of channel-like, parallel aligned pores, running through the whole length of the biphasic constructs. The synthesis process leads to an anisotropic structure, as it is found in many natural tissues. The two different layers of the scaffolds are characterized by different microstructure and mechanical properties which provide a suitable environment for cells to form the respective tissue. Human chondrocytes and human mesenchymal stem cells were embedded within the chondral layer of the biphasic scaffolds during hydrogel formation and their chondrogenic (re)differentiation was successfully induced. Whereas viability of non-induced human mesenchymal stem cells decreased during culture, cell viability of human chondrocytes and chondrogenically induced human mesenchymal stem cells remained high within the scaffolds over the whole culture period of 3 weeks, demonstrating successful fabrication of cell-laden centimetre-scaled constructs for potential application in regenerative treatment of osteochondral defects. Copyright © 2014 John Wiley & Sons, Ltd. Copyright © 2014 John Wiley & Sons, Ltd.

  16. Osteochondral fragmentation in the synovial pad of the fetlock in Warmblood horses.

    Science.gov (United States)

    Declercq, Jeroen; Martens, Ann; Bogaert, Lies; Boussauw, Bernard; Forsyth, Ramses; Boening, Karl Josef

    2008-10-01

    To determine clinical and arthroscopic characteristics associated with fragments in the synovial pad of the fetlock and to characterize their morphology. Retrospective study. Warmblood horses (n=104) with fragment(s) in the synovial pad. Signalment and results of radiographic and clinical examination were collected before surgery. After arthroscopic fragment removal and joint evaluation for synovial and/or cartilage abnormalities, fragments were measured, and evaluated by histopathology. Synovial pad fragments (n=142) were removed from 127 fetlocks. Two older horses had lameness. During arthroscopy, abnormalities were observed in 40 joints (31.5%) and multivariate logistic regression analysis showed a significant correlation between the observed arthroscopic abnormalities and the presence of large fragments (P=.016). Fragments were osteochondral bodies completely surrounded by fibrous tissue. At the edges of the hyaline cartilage cap an underlying fibrous structure was obvious in the extracellular matrix giving it a reactive pattern. Although the impact on lameness was minimal, there was a significant correlation between arthroscopic abnormalities and presence of large synovial pad fragments. On histopathology, these osteochondral fragments are embedded in fibrous tissue and show a reactive pattern. They are not a manifestation of any well-described joint pathology. Large synovial pad fragments in Warmblood horses can be associated with synovial and cartilage abnormalities, but further studies are warranted to determine their origin and clinical importance.

  17. Platelet rich plasma associated with heterologous fresh and thawed chondrocytes on osteochondral lesions of rabbits

    Directory of Open Access Journals (Sweden)

    R.R. Filgueiras

    2014-02-01

    Full Text Available Chondrocytes obtained from stifle joint of New Zealand White rabbits were cultivated. Half of cells were maintained in culture for later implantation and the others frozen during six months to evaluate viability. A circular osteochondral defect was created in the right stifle of other twenty seven rabbits. The control group (CG received no treatment. The thawed (TH and fresh (FH heterologous groups received, respectively, an implant of cultivated thawed or fresh heterologous chondrocytes associated with platelet rich plasma (PRP. The CG group showed greatest pain and lameness compared to the other groups seven days after the implantation. Microscopically, at 45 and 90 days, the TH and FH groups showed filling with cartilaginous tissue containing chondrocytes surrounded by a dense matrix of glycosaminoglycans. In the CG group, healing occurred with vascularized fibrous connective tissue without integration to the subchondral bone. Cryopreserved heterologous chondrocytes were viable for implantation and healing of osteochondral lesions; the association with PRP allows the fixation of cells in the lesion and offers growth factors which accelerates repair with tissue similar to articular hyaline cartilage.

  18. [Attitude towards organ and tissue donation in Europe : Prerequisite for osteochondral allograft treatment].

    Science.gov (United States)

    Schmidt, S; Schulte, A; Schwarz, S; Hofmann, N; Tietz, S; Boergel, M; Sixt, S U

    2017-09-27

    The biggest obstacle to overcome for routine treatment of various pathologies with fresh osteochondral allograft is the availability of tissue for transplantation. Large fresh osteochondral allografts are usually harvested from organ donors, but in contrast to organs, tissues can be procured after cardiac arrest. Medical staff as well the general public are much less aware of the possibilities and requirements of tissue donation compared to organ donation. This review aims to highlight the current situation of organ and tissue donation in Europe and to raise this much needed awareness. For this research, PubMed database was scanned using the terms "tissue/organ donation", "bone donation/transplantation", "cartilage transplantation/allografts" and "osteochrondral allografts". Relatives of potential donors are often not approached because physicians and nurses do not feel sufficiently prepared for this task and, thus, are reluctant to address this topic. Different options could alleviate the pressure medical staff is feeling. Furthermore, there are different factors influencing consent that can be addressed to increase donation rates. Currently, a lot of potential concerning musculoskeletal tissue grafts remains unused. Most importantly, families should be encouraged to speak about their potenzial will to donate and educational programs should be established to increase trust in organ and tissue donation and the allocation system and to increase knowledge about the importance of transplantation medicine. But joined efforts of different parts of the medical systems and different organizations involved in tissue transplantation should improve the situation for patients waiting for much needed transplants.

  19. Transplante osteocondral autólogo no tratamento de lesões osteocondrais em atletas Osteochondral autograft transplantation for the treatment of osteochondral defects in athletes

    Directory of Open Access Journals (Sweden)

    João Paris Buarque de Hollanda

    2010-01-01

    Full Text Available OBJETIVO: Avaliar o resultado clínico da técnica de transplante osteocondral autólogo (TOA para tratamento das lesões osteocondrais do joelho de atletas. MÉTODOS: Em um seguimento médio de 52 meses (30 a 82 meses, 19 pacientes foram avaliados pré e pós-operatoriamente pelos protocolos do IKDC subjetivo, Cincinnati modificado e nível de retorno aos esportes. O prognóstico conforme idade, tempo de sintomatologia, presença de lesões associadas e local da lesão também foi avaliado. RESULTADOS: O valor de IKDC foi de 64,6 + 6,8 no pré-operatório e de 81,8 + 20,1 no pós-operatório. O Cincinnati modificado foi de 5,3 + 0,8 no pré-operatório e de 7,5 + 1,7 no pós-operatório. 53% dos pacientes retornaram aos esportes no nível anterior à lesão, 29% em nível inferior e 17% abandonaram a prática esportiva regular. Os melhores resultados clínicos foram observados em pacientes menores de 35 anos, com menos de um ano de sintomas, com lesões nos côndilos femorais e sem lesões menisco ligamentares associadas. Resultados piores foram observados nas lesões da tróclea quando comparados aos dos côndilos femorais. CONCLUSÃO: Joelhos submetidos ao TOA têm uma melhora subjetiva significativa após a cirurgia. O retorno ao esporte ocorre em um grupo específico de pacientes.OBJECTIVE: To evaluate clinical outcomes of the osteochondral autologous transplantation technique for treatment of osteochondral defects of the knee in athletes. METHODS: For an average follow-up period of 52 months (30 to 82 months, 19 patients were evaluated pre and post-operatively by using subjective IKDC scores, modified Cincinnati Scores, and rate of return to sports activities. Prognosis according to age, duration of symptoms and location of the lesion was also evaluated. RESULTS: Subjective IKDC scores were 64.6 + 6.8 pre-operatively and 81.8 + 20.1 post-operatively. Modified Cincinnati score was 5.3 + 0.8 pre-operatively and 7.5 + 1.7 post

  20. Effects of Pulsed Electromagnetic Fields on Return to Sports After Arthroscopic Debridement and Microfracture of Osteochondral Talar Defects: A Randomized, Double-Blind, Placebo-Controlled, Multicenter Trial

    NARCIS (Netherlands)

    Reilingh, Mikel L.; van Bergen, Christiaan J. A.; Gerards, Rogier M.; van Eekeren, Inge C.; de Haan, Rob J.; Sierevelt, Inger N.; Kerkhoffs, Gino M. M. J.; Krips, Rover; Meuffels, Duncan E.; van Dijk, C. N.; Blankevoort, Leendert

    2016-01-01

    Osteochondral defects (OCDs) of the talus usually affect athletic patients. The primary surgical treatment consists of arthroscopic debridement and microfracture. Various possibilities have been suggested to improve the recovery process after debridement and microfracture. A potential solution to

  1. [Technological aspects of regenerative medicine and tissue engineering of articular cartilage].

    Science.gov (United States)

    Pörtner, R; Meenen, N M

    2010-12-01

    The main problem in the treatment of orthopaedic joint-surface defects will be solved by tissue engineering of cartilage implants. Entire biological osteochondral implants can be grown from autologous cells of the patient. The nutrition of articular cartilage is by diffusion only. Therefore the chondrocyte as the unique cell type is perfectly dedicated to the tissue culture approach. Engineering techniques of bioreactors are prerequisite for these biological and medical solutions. With our tissue engineering project for the generation of osteochondral constructs we demonstrate possibilities and characteristics of bioreactors for the modification of cell culture techniques and mechanical conditioning of cartilage tissue for fully operable implants. © Georg Thieme Verlag KG Stuttgart · New York.

  2. Novel Application of Magnetic Resonance Imaging Demonstrates Characteristic Differences in Vasculature at Predilection Sites of Osteochondritis Dissecans.

    Science.gov (United States)

    Tóth, Ferenc; Nissi, Mikko J; Ellermann, Jutta M; Wang, Luning; Shea, Kevin G; Polousky, John; Carlson, Cathy S

    2015-10-01

    Understanding the pathogenesis of osteochondrosis/osteochondritis dissecans and other developmental orthopaedic diseases that are thought to occur secondary to defects in vascular supply to growth/epiphyseal cartilage has been hampered by the inability to image the vasculature in this tissue. This is particularly true in human beings due to limitations of current imaging techniques and the lack of availability of appropriate cadaveric samples for histological studies. Susceptibility-weighted imaging, an MRI sequence, allows identification of characteristic differences in the vascular architecture in species that are affected by osteochondrosis/osteochondritis dissecans on the femoral condyle (humans and pigs) versus a species that is free of the disease (goat). Controlled laboratory study. Distal femora from cadavers of juvenile humans (n = 5), pigs (n = 3), and goats (n = 3) were scanned in a 9.4-T MRI scanner using susceptibility-weighted imaging. Three-dimensional reconstructions were created, and minimum intensity projections were calculated in 3 planes to enhance visualization of the vascular architecture. Susceptibility-weighted imaging allowed clear visualization of the epiphyseal vasculature in all species. Vascular architecture, with vessels primarily arising from the perichondrium, was similar in humans and pigs, which are predisposed to osteochondrosis/osteochondritis dissecans, and was starkly different from that present in goats, a species in which there are no reports of osteochondrosis/osteochondritis dissecans. Furthermore, vessels in the distal femoral predilection site disappeared with age in humans in a pattern similar to that reported previously in pigs. Nearly identical vascular architecture at the shared primary predilection site of osteochondrosis/osteochondritis dissecans in the femoral condyles in human beings and pigs suggests that vascular failure, which is known to be central to the pathogenesis of this disease in pigs, may also play a

  3. Hydrogel-Based Platforms for the Regeneration of Osteochondral Tissue and Intervertebral Disc

    Directory of Open Access Journals (Sweden)

    Luigi Ambrosio

    2012-09-01

    Full Text Available Hydrogels currently represent a powerful solution to promote the regeneration of soft and hard tissues. Primarily, they assure efficient bio-molecular interactions with cells, also regulating their basic functions, guiding the spatially and temporally complex multi-cellular processes of tissue formation, and ultimately facilitating the restoration of structure and function of damaged or dysfunctional tissues. In order to overcome basic drawbacks of traditional synthesized hydrogels, many recent strategies have been implemented to realize multi-component hydrogels based on natural and/or synthetic materials with tailored chemistries and different degradation kinetics. Here, a critical review of main strategies has been proposed based on the use of hydrogels-based devices for the regeneration of complex tissues, i.e., osteo-chondral tissues and intervertebral disc.

  4. Snapping popliteus tendon within an osteochondritis dissecans lesion: an unusual case of lateral knee pain.

    Science.gov (United States)

    Shukla, Dave R; Levy, Bruce A; Kuzma, Scott A; Stuart, Michael J

    2014-09-01

    The popliteus muscle is an important structure in the posterior knee, coursing from the distal lateral femoral condyle to the posterior tibia, and it initiates knee flexion, protects the lateral meniscus, and resists tibial external rotation. Abnormalities in the lateral femoral condyle may result in impaired tracking of the popliteus tendon over the lateral femoral condyle, causing pain and a snapping sensation. We report a case of a snapping popliteus tendon caused by an osteochondral defect of the lateral femoral condyle. We obtained a thorough medical history, performed a detailed physical examination, and performed diagnostic ultrasonography to accurately diagnose the condition. The patient underwent open popliteus tenotomy and tibial tenodesis with excellent results and full return to activity. Any abnormality of the lateral femoral condyle may predispose patients to snapping popliteus tendon and we believe early diagnosis utilizing ultrasonography imaging and surgical intervention may benefit these patients significantly.

  5. A volleyball player with bilateral knee osteochondritis dissecans treated with extracorporeal shock wave therapy.

    Science.gov (United States)

    Moretti, Biagio; Notarnicola, Angela; Moretti, Lorenzo; Giordano, Paola; Patella, Vittorio

    2009-05-01

    We present a case report of a 14-year-old Caucasian sport woman affected by bilateral and symmetrical knee osteochondritis dissecans (OCD) addressed to surgery, in which extracorporeal shock wave therapy determined complete healing. Shock wave is a longitudinal acoustic wave traveling with the speed of ultrasound through the water of the body tissue. Recently, this therapy has been used in the treatment of a number of musculoskeletal pathologies on the basis of the effects produced by the induction of angiogenesis, recruitment of progenitor cells and downregulation of cartilage damage. This therapy is useful, because it is non-invasive, safe, without complications or adverse effects and repeatable. Thus, it could be suggested as a useful strategy for the treatment of OCD prior starting surgery.

  6. Autologous chondrocyte implantation for the treatment of chondral and osteochondral defects of the talus

    DEFF Research Database (Denmark)

    Niemeyer, Philipp; Salzmann, Gian; Schmal, Hagen

    2012-01-01

    for talar lesions was aim of the present meta-analysis. METHODS: An OVID-based literature search was performed to identify any published clinical studies on autologous chondrocyte implantation (ACI) for the treatment of pathologies of the ankle including the following databases: MEDLINE, MEDLINE preprints......, EMBASE, CINAHL, Life Science Citations, British National Library of Health, and Cochrane Central Register of Controlled Trials (CENTRAL). Literature search period was from the beginning of 1994 to February 2011. Of 54 studies that were identified, a total of 16 studies met the inclusion criteria...... of the present meta-analysis. Those studies were systematically evaluated. RESULTS: All studies identified represented case series (EBM Leven IV). 213 cases with various treatment for osteochondral and chondral defects with a mean size of 2.3 cm(2) (±0.6) have been reported. A total of 9 different scores have...

  7. Osteochondritis dissecans of the knee joint: A diagnosis not to miss

    Directory of Open Access Journals (Sweden)

    Rahul R Bagul

    2014-01-01

    Full Text Available Osteochondritis dissecans (OCD is the most common cause of a loose body in the joint space in adolescent patients. Diagnosis requires a high index of suspicion as clinical findings are often subtle. Limited range of motion may be the only notable clinical sign. The diagnosis is made by thorough clinical examination, radiographic examination and magnetic resonance imaging (MRI. Early diagnosis and treatment can change the prognosis of the disease. If not diagnosed early, OCD can lead to the development of osteoarthritis at an early age. Conservative management is the mainstay of treatment for stable lesions. While the majority of patients respond to conservative treatment, those with unstable lesions require arthroscopic management.

  8. Non-destructive monitoring of viability in an ex vivo organ culture model of osteochondral tissue.

    Science.gov (United States)

    Elson, K M; Fox, N; Tipper, J L; Kirkham, J; Hall, R M; Fisher, J; Ingham, E

    2015-06-30

    Organ culture is an increasingly important tool in research, with advantages over monolayer cell culture due to the inherent natural environment of tissues. Successful organ cultures must retain cell viability. The aim of this study was to produce viable and non-viable osteochondral organ cultures, to assess the accumulation of soluble markers in the conditioned medium for predicting tissue viability. Porcine femoral osteochondral plugs were cultured for 20 days, with the addition of Triton X-100 on day 6 (to induce necrosis), camptothecin (to induce apoptosis) or no toxic additives. Tissue viability was assessed by the tissue destructive XTT (2,3-bis[2-methoxy-4-nitro-5-sulfophenyl]-2H-tetrazolium-5-carboxyanilide tetrazolium salt) assay method and LIVE/DEAD® staining of the cartilage at days 0, 6 and 20. Tissue structure was assessed by histological evaluation using haematoxylin & eosin and safranin O. Conditioned medium was assessed every 3-4 days for glucose depletion, and levels of lactate dehydrogenase (LDH), alkaline phosphatase (AP), glycosaminoglycans (GAGs), and matrix metalloproteinase (MMP)-2 and MMP-9. Necrotic cultures immediately showed a reduction in glucose consumption, and an immediate increase in LDH, GAG, MMP-2 and MMP-9 levels. Apoptotic cultures showed a delayed reduction in glucose consumption and delayed increase in LDH, a small rise in MMP-2 and MMP-9, but no significant effect on GAGs released into the conditioned medium. The data showed that tissue viability could be monitored by assessing the conditioned medium for the aforementioned markers, negating the need for tissue destructive assays. Physiologically relevant whole- or part-joint organ culture models, necessary for research and pre-clinical assessment of therapies, could be monitored this way, reducing the need to sacrifice tissues to determine viability, and hence reducing the sample numbers necessary.

  9. Osteochondral repair using perichondrial cells. A 1-year study in rabbits.

    Science.gov (United States)

    Chu, C R; Dounchis, J S; Yoshioka, M; Sah, R L; Coutts, R D; Amiel, D

    1997-07-01

    Articular cartilage repair remains a clinical and scientific challenge with increasing interest focused on the transplantation of chondrogenic cells. This study evaluated the repair response during a 1-year period after implantation of allogenic perichondrium cell polylactic acid composite grafts into 3.7 x 5 mm osteochondral defects drilled into the medial femoral condyles of 82 adult New Zealand White rabbits. The repair tissue was evaluated grossly, histologically, histomorphometrically, biochemically, and biomechanically at 6 weeks, 12 weeks, 6 months, and 1 year after implantation. After gross evaluation, cartilaginous material appeared to fill the defect in 70 experimental knees, for an overall repair frequency of 85%. The histomorphometric results and the histologic appearances were variable. None of the specimens were completely normal at 1 year. Only specimens with subchondral bone reformation displayed a definable cartilage appearing surface with chondrocytes surrounded by dense matrix. Subchondral bone reformation was inconsistent, reaching 50% at 1 year. Biochemically, the repair tissue matured during a 1-year period into a hyaline Type II collagen dominant tissue, whereas glycosaminoglycan content remained low at all time periods. The measured compressive properties of the repair tissue at 1 year were not significantly different from those of the contralateral knee that was not surgically treated. The treatment of osteochondral defects in the rabbit knee with allogenic perichondrium cell polylactic acid composite grafts yielded a high percentage of grossly successful repairs that showed inconsistent subchondral bone reformation. These results suggest that healthy subchondral bone is important to articular cartilage repair. They also highlight that a cartilaginous appearing tissue at gross inspection may not represent structurally normal articular cartilage. Continued multidisciplinary studies on the arthroplastic potential of rib perichondrial cells

  10. Osteochondritis dissecans and Osgood Schlatter disease in a family with Stickler syndrome

    Directory of Open Access Journals (Sweden)

    Klaushofer Klaus

    2009-02-01

    Full Text Available Abstract Purpose Stickler syndrome is among the most common autosomal dominant connective tissue disorders but is often unrecognised and therefore not diagnosed by clinicians. Despite much speculation, the cause of osteochondrosis in general and osteochondritis dissecans (OCD and Osgood Schlatter syndrome (OSS in particular remain unclear. Etiological understanding is essential. We describe a pair of family subjects presented with OCD and OSS as a symptom complex rather than a diagnosis. Methods Detailed clinical and radiographic examinations were undertaken with emphasis on the role of MRI imaging. Magnetic resonance imaging may allow early prediction of articular lesion healing potential in patients with Stickler syndrome. Results The phenotype of Stickler syndrome can be diverse and therefore misleading. The expectation that the full clinical criteria of any given genetic disorder such as Stickler syndrome will always be present can easily lead to an underestimation of these serious inheritable disorders. We report here two family subjects, a male proband and his aunt (paternal sister, both presented with the major features of Stickler syndrome. Tall stature with marfanoid habitus, astigmatism/congenital vitreous abnormality and submucus cleft palate/cleft uvula, and enlarged painful joints with early onset osteoarthritis. Osteochondritis dissecans (OCD and Osgood Schlatter syndrome (OSS were the predominating joint abnormalities. Conclusion We observed that the nature of the articular and physeal abnormalities was consistent with a localised manifestation of a more generalised epiphyseal dysplasia affecting the weight-bearing joints. In these two patients, OCD and OSS appeared to be the predominant pathologic musculoskeletal consequences of an underlying Stickler's syndrome. It is empirical to consider generalised epiphyseal dysplasia as a major underlying causation that might drastically affect the weight-bearing joints.

  11. Mechanical properties of native and tissue-engineered cartilage depend on carrier permeability: a bioreactor study.

    Science.gov (United States)

    Hoenig, Elisa; Leicht, Uta; Winkler, Thomas; Mielke, Gabriela; Beck, Katharina; Peters, Fabian; Schilling, Arndt F; Morlock, Michael M

    2013-07-01

    The implantation of osteochondral constructs-tissue-engineered (TE) cartilage on a bone substitute carrier-is a promising method to treat defects in articular cartilage. Currently, however, the TE cartilage's mechanical properties are clearly inferior to those of native cartilage. Their improvement has been the subject of various studies, mainly focusing on growth factors and physical loading during cultivation. With the approach of osteochondral constructs another aspect arises: the permeability of the carrier materials. The purpose of this study was to investigate whether and how the permeability of the subchondral bone influences the properties of native cartilage and whether the bone substitute carrier's permeability influences the TE cartilage of osteochondral constructs accordingly. Consequently, the influence of the subchondral bone's permeability on native cartilage was determined: Native porcine cartilage-bone cylinders were cultivated for 2 weeks in a bioreactor under mechanical loading with and without restricted permeability of the bone. For the TE cartilage these two permeability conditions were investigated using permeable and impermeable tricalciumphosphate carriers under equivalent cultivation conditions. All specimens were evaluated mechanically, biochemically, and histologically. The restriction of the bone's permeability significantly decreased the Young's modulus of native cartilage in vitro. No biochemical differences were found. This finding was confirmed for TE cartilage: While the biochemical parameters were not affected, a permeable carrier improved the cell morphology and mechanical properties in comparison to an impermeable one. In conclusion, the carrier permeability was identified as a determining factor for the mechanical properties of TE cartilage of osteochondral constructs.

  12. Repair of osteochondral defects in the minipig model by OPF hydrogel loaded with adipose-derived mesenchymal stem cells.

    Science.gov (United States)

    de Girolamo, Laura; Niada, Stefania; Arrigoni, Elena; Di Giancamillo, Alessia; Domeneghini, Cinzia; Dadsetan, Mahrokh; Yaszemski, Michael J; Gastaldi, Dario; Vena, Pasquale; Taffetani, Matteo; Zerbi, Alberto; Sansone, Valerio; Peretti, Giuseppe M; Brini, Anna T

    2015-01-01

    Critical knee osteochondral defects in seven adult minipigs were treated with oligo(polyethylene glycol)fumarate (OPF) hydrogel combined with autologous or human adipose-derived stem cells (ASCs), and evaluated after 6 months. Four defects were made on the peripheral part of right trochleas (n = 28), and treated with OPF scaffold alone or pre-seeded with ASCs. A better quality cartilage tissue characterized by improved biomechanical properties and higher collagen type II expression was observed in the defects treated by autologous or human ASC-loaded OPF; similarly this approach induced the regeneration of more mature bone with upregulation of collagen type I expression. This study provides the evidence that both porcine and human adipose-derived stem cells associated to OPF hydrogel allow improving osteochondral defect regeneration in a minipig model.

  13. Custom-Designed MLPA Using Multiple Short Synthetic Probes Application to Methylation Analysis of Five Promoter CpG Islands in Tumor and Urine Specimens from Patients with Bladder Cancer

    DEFF Research Database (Denmark)

    Serizawa, R.R.; Ralfkiaer, U.; Dahl, C.

    2010-01-01

    will form a single amplifiable template whose length is defined by the number and lengths of the individual probes. We have used this principle to establish a methylation-specific MLPA (MS-MLPA) assay that simultaneously determines the methylation status of five promoter CpG islands, and we have used...... this assay to analyze DNA from tumor tissue and corresponding urine samples from patients with bladder cancer. Our data show that the use of multiple short synthetic probes provides a simple means for custom-designed MS-MLPA analysis....

  14. Custom-Designed MLPA Using Multiple Short Synthetic Probes Application to Methylation Analysis of Five Promoter CpG Islands in Tumor and Urine Specimens from Patients with Bladder Cancer

    DEFF Research Database (Denmark)

    Serizawa, R.R.; Ralfkiaer, U.; Dahl, C.

    2010-01-01

    will form a single amplifiable template whose length is defined by the number and lengths of the individual probes. We have used this principle to establish a methylation-specific MLPA (MS-MLPA) assay that simultaneously determines the methylation status of five promoter CpG islands, and we have used...... this assay to analyze DNA from tumor tissue and corresponding urine samples from patients with bladder cancer. Our data show that the use of multiple short synthetic probes provides a simple means for custom-designed MS-MLPA analysis. (J Mol Diagn 2010, 12:402-408; DOI: 10.2353/jmoldx.2010.090152)...

  15. Incidence, frequency and clinical relevance of proximopalmar and -plantar osteochondral fragments in the fetlock-joints of horses

    OpenAIRE

    Ohlhaber, Meike

    2010-01-01

    As an introduction, the literature on anatomy and biomechanics of the fetlock joint is discussed. Forms of proximopalmar and proximoplantar osteochondral fragments are described. Localisation, aetiology, pathogenesis, incidence, frequency and radiographic findings are discussed in detail. For the present study the author evaluated archived records of four German equine clinics. A total of 22184 horses, whose fetlock joints were x-rayed could be taken into consideration for this study. 560 out...

  16. Histochemical characterization of human osteochondral tissue: comparison between healthy cartilage, arthrotic tissues, and cartilage defect treated with MACI technique

    Directory of Open Access Journals (Sweden)

    F. Tessarolo

    2011-01-01

    Full Text Available Matrix-induced sutologous chondrocytes implantation (MACI is a promising technique for the treatment of articular cartilage lesions, but long time outcome have to be established. We developed and optimized specific techniques of histochemical staining to characterize healthy and pathologic osteochondral tissue. Seven different staining protocols were applied to assess tissue architecture, cells morphology, proteoglycan content, and collagen fibers distribution. Potentialities of histochemical staining and histomorphology of biopsies from second look arthroscopy will be presented.

  17. Diagnostic sensitivity of radiography, ultrasonography, and magnetic resonance imaging for detecting shoulder osteochondrosis/osteochondritis dissecans in dogs.

    Science.gov (United States)

    Wall, Corey R; Cook, Cristi R; Cook, James L

    2015-01-01

    Radiography, magnetic resonance imaging (MRI), and ultrasonography are commonly used for diagnosis of shoulder osteochondrosis and osteochondritis dissecans (OC/OCD) in dogs, however there is a lack of published information on the relative diagnostic sensitivities of these modalities. The purpose of this prospective study was to compare diagnostic sensitivities of these modalities for detecting shoulder OC/OCD in a group of dogs, using arthroscopy as the reference standard. Inclusion criteria were history and clinical findings consistent with osteochondrosis and/or osteochondritis dissecans involving at least one shoulder. With informed client consent, both shoulders for all included dogs were examined using standardized radiography, ultrasonography, MRI, and arthroscopy protocols. One of three veterinary surgeons recorded clinical and arthroscopic findings without knowledge of diagnostic imaging findings. One of two veterinary radiologists recorded diagnostic imaging findings without knowledge of clinical and arthroscopic findings. Eighteen client-owned dogs (n = 36 shoulders) met inclusion criteria. Diagnostic sensitivity, specificity, and accuracy (correct classification rate) values for detecting presence or absence of shoulder osteochondrosis/osteochondritis dissecans were as follows: radiography (88.5%, 90%, 88.9%), ultrasonography (92%, 60%, 82.6%), and MRI (96%, 88.9%, 94.4%). Odds of a correct diagnosis for MRI were 3.2 times more than ultrasonography and two times more than radiography. For MRI detection of lesions, the sagittal T2 or PD-FAT SAT sequences were considered to be most helpful. For radiographic detection of lesions, the additional supinated-mediolateral and pronated-mediolateral projections were considered to be most helpful. Findings from the current study support more evidence-based diagnostic imaging recommendations for dogs with clinically suspected shoulder osteochondrosis or osteochondritis dissecans. © 2014 American College of

  18. An experimental intraarticular implantation of woven carbon fiber pad into osteochondral defect of the femoral condyle in rabbit.

    Science.gov (United States)

    Kang, H J; Han, C D; Kang, E S; Kim, N H; Yang, W I

    1991-06-01

    The defects of the articular cartilage structure are not replaced unless the subchondral plate has been breached. However, following the creation of a defect in the subchondral plate, the area is filled in with a fibrous tissue which gradually transforms to hyaline cartilage. The porous nontoxic materials of both biologic and synthetic origin have reportedly been used as matrices for repairing bone and cartilage. Following implantation, carbon fibre, chemically inert and well-tolerated by the body, induces a proliferation of ordered fibrous tissue. We implanted carbon fiber pads in osteochondral defects in rabbits. Those repairs were compared to control holes with no implants. The pads appeared to induce the gross appearance of a restored joint surface, mechanically strong to loading for periods from 2 to 6 weeks. Also, carbon fiber pads promoted the healing of the osteochondral defects in the rabbit femoral condyle, supplying well-organized cartilagenous tissue over repaired subchondral bone. The use of carbon fiber pads as implant material is suggested for the restoration of articular surface in osteoarthritis and osteochondritis dissecans.

  19. Autologous osteochondral grafting (mosaic arthroplasty) for treatment of subchondral cystic lesions in the equine stifle and fetlock joints.

    Science.gov (United States)

    Bodo, Gabor; Hangody, Laszlo; Modis, Laszlo; Hurtig, Mark

    2004-01-01

    To describe treatment of equine subchondral bone cysts (SBCs) by reconstruction of the articular surface with osteochondral grafts. Case series of horses with SBCs unresponsive to conservative therapy. Eleven horses (1-12 years). SBCs were identified in 4 locations: medial femoral condyle (5 horses), lateral femoral condyle (1), distal epiphysis of the metacarpus (4), or metatarsus (1). Osteochondral autograft transplantation (mosaic arthroplasty) was performed, taking grafts from the abaxial border of the medial femoral trochlea of the unaffected limb. Graft implantation was achieved through a small arthrotomy or by arthroscopy depending on SBC location. All horses improved postoperatively; 10 horses had successful outcomes with radiographic evidence of successful graft incorporation and 7 returned to a previous or higher activity level. On follow-up arthroscopy (5 horses) there was successful reconstitution of a functional gliding surface. One horse had delayed incorporation of a graft because of a technical error but became sound. One horse had recurrence after 4 years of work and soundness. One stallion was used for breeding and light riding because of medial meniscal injuries on the same limb. Implantation of osteochondral grafts should be considered for SBC when conservative management has not improved lameness and there is a risk of further joint injury and degeneration. Mosaic arthroplasty should be considered for treatment of subchondral bone cysts of the femoral condyle and distal articular surface of the metacarpus/tarsus in horses that are refractory to non-surgical management.

  20. Heritabilities and genetic correlations between fetlock, hock and stifle osteochondrosis and fetlock osteochondral fragments in Hanoverian Warmblood horses.

    Science.gov (United States)

    Hilla, D; Distl, O

    2014-02-01

    The main objective of this study is to estimate genetic parameters for osteochondrosis (OC) and osteochondrosis dissecans (OCD) in fetlock, hock and stifle joints as well as for palmar or plantar osteochondral fragments (POFs) and dorsodistal osteochondral fragments (DOFs) in fetlock joints. For this purpose, the results of a standardized radiographic examination of 7396 Hanoverian Warmblood horses were used. Heritabilities and genetic correlations were estimated using residual maximum likelihood (REML) under a linear animal model. Heritability estimates for OC at the different joints were at 0.17-0.34, for OCD at 0.16-0.46, for POFs at 0.19 and for DOFs at 0.22 after transformation onto the liability scale. For osteochondral fragments (OFs), lower heritabilities were estimated, especially in fetlock joints. POFs were genetically negatively correlated with OC in each joint. The size of the heritability estimates indicates that the prevalence of these radiographic findings can be reduced by breeding measures. However, differentiation among the different clinical entities is crucial to avoid underestimation of heritabilities. The analysis of genetic parameters performed in this study indicates that OC and OCD in fetlock, OC and OCD in hock, OC and OCD in stifle joints, POFs of the hindlimbs and DOFs may be treated as different traits. © 2013 Blackwell Verlag GmbH.

  1. Tibial plateau lesions. Surface reconstruction with a biomimetic osteochondral scaffold: Results at 2 years of follow-up.

    Science.gov (United States)

    Kon, Elizaveta; Filardo, Giuseppe; Venieri, Giulia; Perdisa, Francesco; Marcacci, Maurilio

    2014-12-01

    Tibial plateau articular pathology caused by post-traumatic or degenerative lesions is a challenge for the orthopaedic surgeon and can lead to early osteoarthritis. The aim of the present study was to evaluate the results of treatment of these complex defects with implantation of an osteochondral scaffold, which is designed to target the cartilage surface and to reconstruct joint anatomy by addressing the entire osteochondral unit. Eleven patients (5 female and 6 male) with a mean age of 37.3 ± 11.0 years and osteochondral lesions of the tibial plateau (mean 5.1 ± 2.7 cm(2); range 3.0-12.5 cm(2)) were treated with the implantation of an osteochondral biomimetic collagen-hydroxyapatite scaffold (Maioregen(®), Fin-Ceramica, Faenza, Italy). Comorbidities were addressed taking care to restore the correct limb alignment. Patients were evaluated pre-operatively and prospectively followed-up for 2 years using the International Knee Documentation Committee (IKDC) subjective and objective scores; activity level was documented using the Tegner score. Three patients experienced minor adverse events. No patients required further surgery for treatment failure during the study follow-up period, and 8 patients (72.7%) reported a marked improvement. The IKDC subjective score improved from 42.5 ± 10.2 before treatment to 69.8 ± 19.0 at 12 months (p<0.05), with stable results at 24 months. The IKDC objective score increased from 27.3% normal and nearly normal knees before treatment to 85.7% normal and nearly normal knees at 24 months of follow-up. The Tegner score increased from 2.3 ± 2.1 before treatment to 4.8 ± 2.4 at 12 months (p<0.05), and was stable at the final follow-up. The present study on the implantation of an osteochondral scaffold for the treatment of tibial plateau lesions showed a promising clinical outcome at short-term follow-up, which indicates that this procedure can be considered as a possible treatment option, even in these complex defects, when

  2. Return to an athletic lifestyle after osteochondral allograft transplantation of the knee.

    Science.gov (United States)

    Shaha, James S; Cook, Jay B; Rowles, Douglas J; Bottoni, Craig R; Shaha, Steven H; Tokish, John M

    2013-09-01

    Osteochondral allograft transplantation (OATS) is a treatment option that provides the ability to restore large areas of hyaline cartilage anatomy and structure without donor site morbidity and promising results have been reported in returning patients to some previous activities. However, no study has reported on the durability of return to activity in a setting where it is an occupational requirement. Osteochondral allograft transplantation is less successful in returning patients to activity in a population in which physical fitness is a job requirement as opposed to a recreational goal. Case series; Level of evidence, 4. A retrospective review was conducted of 38 consecutive OATS procedures performed at a single military institution by 1 of 4 sports medicine fellowship-trained orthopaedic surgeons. All patients were on active duty at the time of the index procedure, and data were collected on demographics, return to duty, Knee Injury and Osteoarthritis Outcome Score (KOOS), and ultimate effect on military duty. Success was defined as the ability to return to the preinjury military occupational specialty (MOS) with no duty-limiting restrictions. The mean lesion size treated was 487.0 ± 178.7 mm(2). The overall rate of return to full duty was 28.9% (11/38). An additional 28.9% (11/38) were able to return to limited activity with permanent duty modifications. An alarming 42.1% (16/38) were unable to return to military activity because of their operative knee. When analyzed for return to sport, only 5.3% (2/38) of patients were able to return to their preinjury level. Eleven patients underwent concomitant procedures. Statistical power was maintained by analyzing data in aggregate for cases with versus without concomitant procedures. When the 11 undergoing concomitant procedures were removed from the data set, the rate of return to full activity was 33.3% (9/27), with 22.3% (6/27) returning to limited activity and 44.4% (12/27) unable to return to activity. In this

  3. Osteochondritis Dissecans in Crioulo Foals (Case Report OSTEOCONDRITE DISSECANTE EM POTROS DA RAÇA CRIOULA

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    Márcio Nunes Correa

    2008-12-01

    Full Text Available The aim of this paper was to describe the manifestation of developmental orthopedic diseases, particularly Osteochondritis Dissecans (OCD, in Crioulo foals, considering the clinical sings, radiological study and the animal’s diet. Were evaluated three foals from Crioulo breed presenting volume increase in the knee, fore fetlock and hind fetlock joints. The foals were submitted to radiological examination of the affected joints, showing irregular images in the growing plates region and radiolucent areas in the distal portion of the radius e first phalanx, characterizing the presence of degenerative lesions of the articular cartilage.  The bromatological study of the pastures was made demonstrating imbalances in the calcium-phosphorus relation, being this one of the mains factors involved in the development of OCD lesions. The diagnosis was perform based on the clinical e radiological changes, besides the animal’s diet, age group and practiced exercise.

    KEY WORDS: Crioulo,  DOD, equine, osteochondritis dissecans, orthopedics. Este estudo teve como objetivo descrever a manifestação de distúrbios ortopédicos do desenvolvimento, particularmente a osteocondrite dissecante (OCD, em potros da raça Crioula, levando em consideração os sinais clínicos, estudo radiológico e a dieta dos animais. Avaliaram-se três potros da raça Crioula que apresentaram aumento de volume nas articulações radiocárpicas, metacarpofalangeanas e metatarsofalangeanas. Estes foram submetidos a exame radiológico das regiões afetadas, demonstrando áreas de irregularidade nas placas de crescimento e áreas radioluscentes na porção distal do rádio e primeira falange, caracterizando a presença de lesões degenerativas da cartilagem articular. Desenvolveu-se estudo bromatológico das pastagens, verificando-se desequilíbrios na relação cálcio–fósforo, sendo este um dos principais fatores envolvidos no desenvolvimento de lesões de OCD. O diagn

  4. Surgical treatment of osteochondritis dissecans of the talus: a systematic review.

    Science.gov (United States)

    Zwingmann, Jörn; Südkamp, Norbert P; Schmal, Hagen; Niemeyer, Philipp

    2012-09-01

    Osteochondritis dissecans (OCD) is an aseptic bone necrosis and represents pathology of high clinical relevance, which is frequently located on the talus. Various treatment strategies including non-surgical and surgical approaches have been described. An evidence-based treatment algorithm is still lacking. The present systematic review focuses on surgical treatment options and their stage-dependent outcome described for treatment of osteochondritis dissecans of the talus with special regard to the best available evidence. For this purpose, an OVID-based systematic literature search was performed including the following databases; MEDLINE, MEDLINE preprints, EMBASE, CINAHL, Life Science Citations, British National Library of Health and Cochrane Central Register of Controlled trials (CENTRAL). Literature search period was from January 1967 up to December 2009. After applying study specific inclusion criteria (minimum follow-up 12 months, patient evaluation by standardized scoring systems, etc.), a total of 54 studies with clinical follow-up of 1,105 patients was included. Methodology of these studies was systematically analyzed by the means of the Coleman Methodology Score. Outcome and success rate was evaluated in dependence of surgical treatment applied and in dependence of the stage of disease. All 54 studies included were classified as evidence level IV representing case series. The average Coleman Methodology Score was 63 (SD ± 17) points. The average follow-up of the 1,105 patients was 47 months (SD ± 17) with a mean age of 29 (SD ± 5.6) years. The proportion of excellent and good treatment results was stage-independent in total 75 %. According to the criteria of the score applied for patient's evaluation in the individual study, the overall percentage of "good" and "excellent" clinical outcome in 869 patients was 79 %, and according the classification of Berndt and Harty, 82 % in stage I, 86 % in stage II, 83 % in stage III and 76 % in stage IV. Although

  5. Ossification variants of the femoral condyles are not associated with osteochondritis dissecans

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    Jans, L., E-mail: lennartjans@hotmail.com [Department of Radiology and Medical Imaging, Ghent University Hospital, De Pintelaan 185, 9000 Gent (Belgium); Jaremko, J., E-mail: jjaremko@gmail.com [Department of Radiology, University of Alberta Hospital, 8440-112 Street, Edmonton T6G 2B7, Alberta (Canada); Ditchfield, M., E-mail: Michael.ditchfield@southernhealth.org.au [Department of Radiology, Monash University Clayton Campus, Wellington Road, Clayton 3800, VIC (Australia); De Coninck, T., E-mail: Tinekedeconinck@ugent.be [Department of Radiology and Medical Imaging, Ghent University Hospital, De Pintelaan 185, 9000 Gent (Belgium); Huysse, W., E-mail: Wouter.huysse@ugent.be [Department of Radiology and Medical Imaging, Ghent University Hospital, De Pintelaan 185, 9000 Gent (Belgium); Moon, A., E-mail: Anna.moon@rch.org.au [Department of Radiology, Royal Children' s Hospital, Flemington Road, Parkville 3052, VIC (Australia); Verstraete, K., E-mail: Koenraad.verstraete@ugent.be [Department of Radiology and Medical Imaging, Ghent University Hospital, De Pintelaan 185, 9000 Gent (Belgium)

    2012-11-15

    Purpose: To determine if ossification variants of the femoral condyles involving the subchondral bone plate are associated with osteochondritis dissecans (OCD). Materials and methods: The prevalence of ossification variants of the unaffected femoral condyle in 116 patients (aged 9-14 years) with unicondylar OCD on MRI (magnetic resonance imaging) of the knee was compared to a control group of 579 patients (aged 9-14 years) without OCD. The evolution of the ossification variants in both groups was studied by reviewing follow-up MR imaging side by side with the baseline study. Results: The prevalence of ossification variants in the unaffected condyle in patients with OCD (12.9%) and in the control group of patients without OCD (12.6%) was similar (p = 0.88). Evolution of ossification variants to OCD was not seen on follow-up MRI examinations. All variants had decreased in size or were no longer visible. Conclusion: Ossification variants of the femoral condyle that involve the subchondral bone plate are not associated with OCD. Clinical relevance statement: Ossification variants are not associated with OCD, indicating that routine MRI follow-up in affected children is not mandatory.

  6. MRI differentiates femoral condylar ossification evolution from osteochondritis dissecans. A new sign

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    Jans, Lennart B.O.; Huysse, Wouter C.; Verstraete, Koenraad L. [Ghent University Hospital, Department of Radiology and Medical Imaging, Ghent (Belgium); Jaremko, Jacob L.; Ditchfield, Michael [University of Melbourne Royal Children' s Hospital, Department of Medical Imaging, Melbourne, Vic (Australia)

    2011-06-15

    To determine if MRI (magnetic resonance imaging) of the femoral condyles in children can differentiate variations in ossification from osteochondritis dissecans (OCD). MRI studies of the knee of 315 patients demonstrated ossification defects of the femoral condyles involving the subchondral bone plate. MRI features categorized the defects as ossification variability (N = 150) or OCD (N = 165). Both groups were compared for age, residual physeal cartilage, site, configuration, 'lesion angle' and associated findings. (a) Ossification variability did not occur in girls >10 year. and boys >13 year., OCD did not occur in children younger than 8 year. (b) Ossification variability was not seen in patients with 10% or less residual physeal cartilage, OCD was rare in patients with 30% or greater residual physeal cartilage. (c) Ossification variability was located in the posterior third of the femoral condyle, OCD occurred most commonly in the middle third. (d) Intracondylar extension was seen in OCD and not in ossification variability. (e) Perilesional oedema was very common with OCD and absent with ossification variability. (f) Lesion angle <105 was a feature of ossification variability. MRI may help differentiate variations in ossification of the femoral condyles from OCD. (orig.)

  7. Diagnostic Value of CT Arthrography for Evaluation of Osteochondral Lesions at the Ankle

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    Jan S. Kirschke

    2016-01-01

    Full Text Available Background. To retrospectively determine the diagnostic value of computed tomography arthrography (CTA of the ankle in the evaluation of (osteochondral lesions in comparison to conventional magnetic resonance imaging (MRI and intraoperative findings. Methods. A total of N=79 patients had CTAs and MRI of the ankle; in 17/79 cases surgical reports with statements on cartilage integrity were available. Cartilage lesions and bony defects at talus and tibia were scored according to defect depth and size by two radiologists. Statistical analysis included sensitivity analyses and Cohen’s kappa calculations. Results. On CTA, 41/79 and 31/79 patients had full thickness cartilage defects at the talus and at the tibia, respectively. MRI was able to detect 54% of these defects. For the detection of full thickness cartilage lesions, interobserver agreement was substantial (0.72 ± 0.05 for CTA and moderate (0.55 ± 0.07 for MRI. In surgical reports, 88–92% and 46–62% of full thickness defects detected by CTA and MRI were described. CTA findings changed the further clinical management in 15.4% of cases. Conclusions. As compared to conventional MRI, CTA improves detection and visualization of cartilage defects at the ankle and is a relevant tool for treatment decisions in unclear cases.

  8. Computational biomechanics of articular cartilage of human knee joint: effect of osteochondral defects.

    Science.gov (United States)

    Shirazi, R; Shirazi-Adl, A

    2009-11-13

    Articular cartilage and its supporting bone functional conditions are tightly coupled as injuries of either adversely affects joint mechanical environment. The objective of this study was set to quantitatively investigate the extent of alterations in the mechanical environment of cartilage and knee joint in presence of commonly observed osteochondral defects. An existing validated finite element model of a knee joint was used to construct a refined model of the tibial lateral compartment including proximal tibial bony structures. The response was computed under compression forces up to 2000 N while simulating localized bone damage, cartilage-bone horizontal split, bone overgrowth and absence of deep vertical collagen fibrils. Localized tibial bone damage increased overall joint compliance and substantially altered pattern and magnitude of contact pressures and cartilage strains in both tibia and femur. These alterations were further exacerbated when bone damage was combined with base cartilage split and absence of deep vertical collagen fibrils. Local bone boss markedly changed contact pressures and strain patterns in neighbouring cartilage. Bone bruise/fracture and overgrowth adversely perturbed the homeostatic balance in the mechanical environment of articulate cartilage surrounding and opposing the lesion as well as the joint compliance. As such, they potentially contribute to the initiation and development of post-traumatic osteoarthritis.

  9. MRI-guided percutaneous retrograde drilling of osteochondritis dissecans of the talus: a feasibility study

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    Kerimaa, Pekka; Ojala, Risto; Markkanen, Paula; Tervonen, Osmo; Blanco Sequeiros, Roberto [Oulu University Hospital, Department of Radiology, Oulu (Finland); Sinikumpu, Juha-Jaakko; Korhonen, Jussi [Oulu University Hospital, Department of Paediatric Surgery, Oulu (Finland); Hyvoenen, Pekka [Oulu University Hospital, Department of Surgery, Oulu (Finland)

    2014-07-15

    The purpose of this study was to evaluate the feasibility of MRI guidance for percutaneous retrograde drilling in the treatment of osteochondritis dissecans of the talus (OCDT). Four patients, one juvenile and three adults, with one OCDT lesion each and persisting ankle pain after conservative treatment, were treated with MRI-guided retrograde drilling. All lesions were stable and located in the middle or posterior medial third of the talar dome. Pain relief and the ability to return to normal activities were assessed during clinical follow-up. MRI and plain film radiographs were used for imaging follow-up. Technical success was 100 % with no complications and with no damage to the overlying cartilage. All patients experienced some clinical benefit, although only one had complete resolution of pain and one had a relapse leading to surgical treatment. Changes in the pathological imaging findings were mostly very slight during the follow-up period. MRI guidance seems accurate, safe and technically feasible for retrograde drilling of OCDT. Larger series are needed to reliably assess its clinical value. (orig.)

  10. Patient compliance with touchdown weight bearing after microfracture treatment of talar osteochondral lesions.

    Science.gov (United States)

    Polat, Gökhan; Karademir, Gökhan; Akalan, Ekin; Aşık, Mehmet; Erdil, Mehmet

    2017-03-20

    The aim of this study was to prospectively evaluate the compliance of our patients with a touchdown weight bearing (without supporting any weight on the affected side by only touching the plantar aspect of the foot to the ground to maintain balance to protect the affected side from mechanical loading) postoperative rehabilitation protocol after treatment of talar osteochondral lesion (TOL). Fourteen patients, who had been treated with arthroscopic debridement and microfracture, were followed prospectively. The patients were evaluated for weight bearing compliance with using a stationary gait analysis and feedback system at the postoperative first day, first week, third week, and sixth week. The mean visual analog scale (VAS) scores of the patients at the preoperative, postoperative first day, first week, third week, and sixth weeks were 5.5, 5.9, 3.6, 0.9, and 0.4, respectively. The decrease in VAS scores were statistically significant (p compliance, patients should be warned to obey the weight bearing restrictions, and patients should be called for a follow-up at the third postoperative week.

  11. Glucosamine and chondroitin sulfate in the repair of osteochondral defects in dogs - clinical-radiographic analysis

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    Renato Barros Eleotério

    2012-10-01

    Full Text Available Among the proposed treatments to repair lesions of degenerative joint disease (DJD, chondroprotective nutraceuticals composed by glucosamine and chondroitin sulfate are a non-invasive theraphy with properties that favors the health of the cartilage. Although used in human, it is also available for veterinary use with administration in the form of nutritional supplement independent of prescription, since they have registry only in the Inspection Service, which does not require safety and efficacy testing. The lack of such tests to prove efficacy and safety of veterinary medicines required by the Ministry of Agriculture and the lack of scientific studies proving its benefits raises doubts about the efficiency of the concentrations of such active substances. In this context, the objective of this study was to evaluate the efficacy of a veterinary chondroprotective nutraceutical based on chondroitin sulfate and glucosamine in the repair of osteochondral defects in lateral femoral condyle of 48 dogs, through clinical and radiographic analysis. The animals were divided into treatment group (TG and control group (CG, so that only the TG received the nutraceutical every 24 hours at the rate recommended by the manufacturer. The results of the four treatment times (15, 30, 60 and 90 days showed that the chondroprotective nutraceutical, in the rate, formulation and administration at the times used, did not improve clinical signs and radiologically did not influence in the repair process of the defects, since the treated and control groups showed similar radiographic findings at the end of the treatments.

  12. Knee Osteochondral Autologous Transplantation: Long-term MR findings and clinical correlations

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    Tetta, Cecilia, E-mail: cecilia.tetta@ior.i [Radiology, Rizzoli Orthopedic Institute, Bologna (Italy); Busacca, Maurizio; Moio, Antonio; Rinaldi, Raffaella [Radiology, Rizzoli Orthopedic Institute, Bologna (Italy); Delcogliano, Marco; Kon, Elizaveta; Filardo, Giuseppe; Marcacci, Maurilio [Biomechanics Laboratory, Rizzoli Orthopedic Institute, Bologna (Italy); Albisinni, Ugo [Radiology, Rizzoli Orthopedic Institute, Bologna (Italy)

    2010-10-15

    We evaluated long-term magnetic resonance imaging (MRI) features of Knee Osteochondral Autologous Transplantation (OAT)-Mosaicplasty and correlated MRI findings and clinical outcome. Twenty-four patients (mean age 29.9 {+-} 8.7, 70.8% male) undergoing arthroscopic OAT between 1997 and 2000 were prospectively enrolled. The International Cartilage Repair Society (ICRS)/International Knee Documentation Committee (IKDC) scores and Tegner scores were employed for clinical evaluation. The magnetic resonance observation of cartilage repair tissue (MOCART) was utilized for description and assessment of the repair tissue. Median follow up was 113 months (interquartile range [IQR] 106-122). MRI showed good survival of grafted cartilage in 62.5% of patients. The integration of the graft was complete in 75% of cases, while the repaired tissue was intact in 62.5% and had an homogeneous structure in 70.8%. The MOCART score significantly correlated with objective and subjective scores (p = 0.003 and p = 0.002). Contrastingly, overall MOCART showed no correlation with the Tegner score. MRI revealed to be a powerful tool for non-invasive long-term assessment of OAT.

  13. A MODERN TREATMENT OF BILATERAL OSTEOCHONDRITIS DISSECANS IN KNEES: FROM A CASE REPORT TO LITERATURE'S REVIEW

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    Marco Corzani

    2017-01-01

    Full Text Available Osteocondrithisdissecans (OCD is an acquired disease due to a subcondral bone ischaemia that affects generally the medial femoral condyle as well as above lying cartilage. Though the incidence of OCD is only 6/10,000 in the general population, in the later stages of disease, OCD fragment can break off inside the articular cavity it is the most Frequently reported cause of free endoarticular body The etiology has been hypothesized as being multi-factored due to traumas or microtraumas along with metabolic, endocrine and genetic disorders leading to subchondral ischemia . Description of case A 15-year old male amateur soccer player presented to our department complaining of recurrent episodes of pain at rest in both knees, swelling and articular blockage occurring over the past 3 years. RX and MRIrevealed bilateral lesions on both medial condyles. A ONE-STEP surgical technique was performed that incorporated the drawing of mesenchymal staminal cells (MSCs and their implantation. Conclusion This case report deals with a rare case of bilateral OCD of the knee treated with the latest technique in regenerative medicine. At 6-month follow up there was a complete return of muscular tonality in both knees andthe patient was allowed to return to light physical activity. These results are noteworthyfor the fact they were obtained from a combined surgical approach that when compared toalternative approaches lead to a shorter hospital stay and a reduced hospital burden. Each of the osteochondral lesions was evaluated from imaging results and arthroscopic findings.

  14. Magnetic resonance imaging in the evaluation of osteochondritis dissecans of the patella

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    Choi, Yun Sun [Hospital for Special Surgery, Weill Medical College of Cornell University, Department of Radiology and Imaging, New York, NY (United States); Eulji Hospital, Eulji University School of Medicine, Department of Radiology, Seoul (Korea); Cohen, Noah A.; Potter, Hollis G.; Mintz, Douglas N. [Hospital for Special Surgery, Weill Medical College of Cornell University, Department of Radiology and Imaging, New York, NY (United States)

    2007-10-15

    The objective was to evaluate the magnetic resonance (MR) appearance of patellar osteochondritis dissecans (OCD). We retrospectively analyzed MR images of 16 patients (18 cases, mean age 20 years) using OCD of the patella. In 5 cases surgery was carried out, and we compared the surgical findings with the MR imaging findings in these cases. In all 18 cases, OCD was located central-inferiorly on the patella, and the average size was 11 x 11 x 7 mm. Subchondral deformities were present in 16 out of 18 cases (88.9%), subchondral cyst formation in 4 cases (22.2%), reactive bone marrow signal in 8 cases (44.4%), overlying patellar cartilage abnormality in 14 cases (77.8%), loose body in 2 cases (11.1%), patella alta in 8 cases (44.4%), hypoplastic sulcus in 7 cases (38.9%), and synovitis in 4 cases (22.2%). In all 5 cases in which surgery was carried out, the cartilage abnormality classified on the MR images was confirmed, and a loose body was removed at arthroscopy in 2 of the 5 cases. Magnetic resonance imaging of patellar OCD typically shows subchondral deformity and variable abnormalities of the overlying patellar cartilage located central-inferiorly on the patella. (orig.)

  15. CT arthrography for evaluation of autologous chondrocyte and chondral-inductor scaffold implantation in the osteochondral lesions of the talus.

    Science.gov (United States)

    De Filippo, Massimo; Azzali, Emanuele; Pesce, Antonella; Saba, Luca; Mostardi, Maurizio; Borgia, Daniele; Barile, Antonio; Capasso, Raffaella; De Palmi, Fabio; Caravaggio, Francesco

    2016-07-28

    to analyse the findings of CT arthrography of the ankle, one year after the transplant of autologous chondrocytes in solution (ACI technique) and the covering with the only scaffold implantation of the osteochondral lesions of the talus, in comparison with the clinical evaluation of the ankle. This retrospective study includes 10 patients (6 male, 4 female, mean age 49.4, range 25-74 years) with an osteochondral lesion of the medial side of the talus, 4 pure chondrals, 6 osteochondrals, painful and limiting the articulation, who underwent ACI using autologous chondrocyte (5 cases) and a covering with the only scaffold implantation (5 cases), in patients who underwent multi-detector CT arthrography between April 2006 and December 2013, at least 12 months after the surgery. Grade 0 was presented in 5 cases (50%), grade 1 in 2 cases (20%), grade 3 in 2 cases (20%) and grade 4 in 1 case (10%). Among the 5 cases even to 0 according to ICRS classification, the patient presented no symptoms in 4 out of 5 cases (80%); in 1 case, the patient presented post-operation pain of moderate entity due to the onset of adhesive capsulitis (20%). The 2 grade 1 patients, according to the ICRS classification, did not report any post-operation pain (0%). The 2 grade 3 patients, according to the ICRS classification, reported a light pain in 1 case (50%). The grade 4 patient, according to the ICRS classification, reported moderate pain (100%). The CT arthrography, for the elevate spatial and contrast resolution, is a very accurate exam in detecting irregularities in the chondral-inductor scaffold implantation, and in correlating the clinical presentation.

  16. MRI-guided percutaneous retrograde drilling of osteochondritis dissecans of the knee

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    Ojala, Risto; Kerimaa, Pekka; Tervonen, Osmo; Blanco-Sequeiros, Roberto [Oulu University Hospital, Department of Radiology, Oulu (Finland); Lakovaara, Martti [Oulu Deaconess Institute, Department of Surgery, Oulu (Finland); Hyvoenen, Pekka; Lehenkari, Petri [Oulu University Hospital, Department of Surgery, Oulu (Finland)

    2011-06-15

    The purpose of this study was to evaluate the feasibility of a new method for osteochondritis dissecans (OCD) treatment. Ten OCD lesions of the knee unresponsive to conservative management were treated with MRI-guided percutaneous retrograde drilling to reduce symptoms and promote ossification of the lesion. All lesions were located in distal femoral condyles. Only stable OCD lesions were included (preprocedural MRI grade I or II). Five lesions were of juvenile type and five lesions were of adult type OCD. All the patients had severe limitation of activity due to the OCD-related pain. By using a 0.23 T open MRI scanner and spinal anesthesia, percutaneous retrograde drilling of the OCD lesions was performed (3 mm cylindrical drill, one to three channels). Optical tracking and MRI imaging were used to guide instruments during the procedure. Mean postprocedural clinical follow-up time was 3 years. Eight patients had a post-procedural follow-up MRI within 1 year. All the OCD lesions were located and drilled using the 0.23 T open MRI scanner without procedural complications. All the patients had pain relief, mean visual analog score (VAS) declined from 6 to 2. Follow-up MRI showed ossification in all lesions. Eight patients could return to normal physical activity with no or minor effect on function (Hughston score 3-4). Treatment failed in two cases where the continuation of symptoms led to arthroscopy and transchondral fixation. MR-guided retrograde OCD lesion drilling is an accurate, feasible, and effective cartilage-sparing techique in OCD management. (orig.)

  17. Influence of juvenile osteochondral conditions on racing performance in Thoroughbreds born in Normandy.

    Science.gov (United States)

    Robert, Céline; Valette, Jean-Paul; Jacquet, Sandrine; Denoix, Jean-Marie

    2013-07-01

    The relationship between osteoarticular status and future athletic capacity is commonly accepted in equine practice, but there is little to support this belief in Thoroughbreds. The objective of this study was to assess the prevalence of juvenile osteochondral conditions (JOCC) in Thoroughbred yearlings and to investigate the significance of these with regard to subsequent racing performance. The radiographic files from 328 Thoroughbred yearlings born in Normandy were assessed in a consistent manner and entered into a database together with racing records. Logistic regression models were used to quantify the association between each radiographic parameter and racing performance (raced/not raced, placed/not placed, performer/not performer) at 2, 3, 4 and 5years of age. The front fetlock (30.2% of horses), the dorsal aspect of the hind fetlock (18%), the carpus (15.9%) and the distal part of the hock (15.5%) were the most commonly affected joints. Most horses (87.5%) raced either in turf flat races or in hurdle races. Starting a race at 2years old was more frequent for yearlings without radiographic findings (RF) on the carpus or with less than one RF of moderate severity. The proportions of horses placed at 3years old decreased with increasing number or severity of RF. In racing horses, there was no association between the presence of RF and earnings. The radiographic score, calculated as the sum of all the severity indices found on the radiographic file of the horse appeared well correlated with performance. Using this synthetic index might help veterinarians to evaluate radiographs of Thoroughbred yearlings for potential buyers. Copyright © 2013 Elsevier Ltd. All rights reserved.

  18. Tri-layered composite plug for the repair of osteochondral defects: in vivo study in sheep

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    Altug Yucekul

    2017-04-01

    Full Text Available Cartilage defects are a source of pain, immobility, and reduced quality of life for patients who have acquired these defects through injury, wear, or disease. The avascular nature of cartilage tissue adds to the complexity of cartilage tissue repair or regeneration efforts. The known limitations of using autografts, allografts, or xenografts further add to this complexity. Autologous chondrocyte implantation or matrix-assisted chondrocyte implantation techniques attempt to introduce cultured cartilage cells to defect areas in the patient, but clinical success with these are impeded by the avascularity of cartilage tissue. Biodegradable, synthetic scaffolds capable of supporting local cells and overcoming the issue of poor vascularization would bypass the issues of current cartilage treatment options. In this study, we propose a biodegradable, tri-layered (poly(glycolic acid mesh/poly(l-lactic acid-colorant tidemark layer/collagen Type I and ceramic microparticle-coated poly(l-lactic acid-poly(ϵ-caprolactone monolith osteochondral plug indicated for the repair of cartilage defects. The porous plug allows the continual transport of bone marrow constituents from the subchondral layer to the cartilage defect site for a more effective repair of the area. Assessment of the in vivo performance of the implant was conducted in an ovine model (n = 13. In addition to a control group (no implant, one group received the implant alone (Group A, while another group was supplemented with hyaluronic acid (0.8 mL at 10 mg/mL solution; Group B. Analyses performed on specimens from the in vivo study revealed that the implant achieves cartilage formation within 6 months. No adverse tissue reactions or other complications were reported. Our findings indicate that the porous biocompatible implant seems to be a promising treatment option for the cartilage repair.

  19. Arthroscopic antegrade drilling for unstable juvenile osteochondritis dissecans of the knee: mid-term results.

    Science.gov (United States)

    Chen, Hong; Xu, Wei; Hu, Ning; Jiang, Dianming; Huang, Wei

    2015-12-01

    The aim of our study was to retrospectively review the mid-term clinical and imaging outcomes of unstable knee juvenile osteochondritis dissecans (JOCD) patients treated with antegrade drilling. Knee arthroscopy and antegrade drilling was performed on 63 knee JOCD patients between 2006 and 2012. Lysholm and Tegner, as well as International Knee Documentation Committee (IKDC), scores were recorded and compared preoperatively and at the latest follow-up. Knee radiographs and magnetic resonance imaging were used to examine lesion healing status. The mean follow-up time was 4.7 years (range 2-7.3 years), and 52 patients finished the follow-up. The average defect size was 2.79 cm(2) (range 1-4 cm(2)). Forty three patients had excellent outcomes with full return to pre-injury activities and reported no symptom recurrence or deterioration over time. The overall healing rate was 82.7 % (43/52). The average Lysholm score was improved from 51.3 to 85.8 (P = 0.001). The mean Tegner activity level was improved from 3.7 to 6.7 (P = 0.013). And the mean IKDC score was improved from 55.7 to 73.2 (P = 0.007). On average, evidence of healing was observed at 11.3 months after surgery (range 6-18 months) Our series showed good to excellent mid-term results in unstable knee JOCD patients who were treated by antegrade drilling. This technique is minimally invasive and effective, as well as cost effective. 4.

  20. Photocrosslinked layered gelatin-chitosan hydrogel with graded compositions for osteochondral defect repair.

    Science.gov (United States)

    Han, Fengxuan; Yang, Xiaoling; Zhao, Jin; Zhao, Yunhui; Yuan, Xiaoyan

    2015-04-01

    A layered gelatin-chitosan hydrogel with graded composition was prepared via photocrosslinking to simulate the polysaccharide/collagen composition of the natural tissue and mimic the multi-layered gradient structure of the cartilage-bone interface tissue. Firstly, gelatin and carboxymethyl chitosan were reacted with glycidyl methacrylate (GMA) to obtain methacrylated gelatin (Gtn-GMA) and carboxymethyl chitosan (CS-GMA). Then, the mixed solutions of Gtn-GMA in different methacrylation degrees with CS-GMA were prepared to form the superficial, transitional and deep layers of the hydrogel, respectively under the irradiation of ultraviolet light, while polyhedral oligomeric silsesquioxane was introduced in the deep layer to improve the mechanical properties. Results suggested that the pore sizes of the superficial, transitional and deep layers of the layered hydrogel were 115 ± 30, 94 ± 34, 51 ± 12 μm, respectively and their porosities were all higher than 80 %. The compressive strengths of them were 165 ± 54, 565 ± 50 and 993 ± 108 kPa, respectively and the strain of the gradient hydrogel decreased along the thickness direction, similar to the natural tissue. The in vitro cytotoxicity results showed that the hydrogel had good cytocompatibility and the in vivo repair results of osteochondral defect demonstrated remarkable recovery by using the gradient gelatin-chitosan hydrogel, especially when the hydrogel loading transforming growth factor-β1. Therefore, it was suggested that the prepared layered gelatin-chitosan hydrogel in this study could be potentially used to promote cartilage-bone interface tissue repair.

  1. Association between intraarticular cytokine levels and clinical parameters of osteochondritis dissecans in the ankle.

    Science.gov (United States)

    Schmal, Hagen; Pilz, Ingo H; Henkelmann, Ralf; Salzmann, Gian M; Südkamp, Norbert P; Niemeyer, Philipp

    2014-05-22

    Reliable data about in vivo regulation of cytokines in osteochondritis dissecans (OCD) of the ankle are still missing. Disease-specific regulation patterns were hypothesized. 28 patients with a mean age of 30.7 ± 14.8 years undergoing an arthroscopy of the ankle because of OCD were prospectively included in a clinical trial. Lavage fluids were analyzed by ELISA for levels of aggrecan, BMP-2, BMP-7, IGF-1, IGF-1R, bFGF, endoglin, MMP-13, and IL-1β. Additionally, clinical parameters and scores (FFI, CFSS, AOFAS) were evaluated and supplemented by the Kellgren Lawrence Score (KLS) for conventional X-rays and the Ankle Osteoarthritis Scoring System (AOSS) for MRI. Grading of OCD lesions statistically significant increased with age and was higher in case of previously performed operations (p<0.03). A worse clinical function reflected by low AOFAS and CFSS scores or high FFI was associated with high grading of cartilage damage or OCD (p<0.03). Similarly, high radiological scores (KLS and AOSS) indicating progress of OA positively correlated with grading of cartilage damage and OCD. The concordance between the MRI and arthroscopic classification was overall moderate (κ=0.52). Biochemically, only IGF/IGF-1R levels were consistently negatively associated with OCD grading, ICRS score, FFI and KLS (p<0.05). Correlation data is supported by post hoc statistics. Radiological and clinical parameters in association with synovial IGF-1/IGF-1R levels indicated an increasing joint degeneration with rising OCD stage. German Clinical Trials Register DRKS00000365, 11/03/2008.

  2. Emerging experimental and computational technologies for purpose designed engineering of photosynthetic prokaryotes

    KAUST Repository

    Lindblad, Peter

    2016-01-25

    With recent advances in synthetic molecular tools to be used in photosynthetic prokaryotes, like cyanobacteria, it is possible to custom design and construct microbial cells for specific metabolic functions. This cross-disciplinary area of research has emerged within the interfaces of advanced genetic engineering, computational science, and molecular biotechnology. We have initiated the development of a genetic toolbox, using a synthetic biology approach, to custom design, engineer and construct cyanobacteria for selected function and metabolism. One major bottleneck is a controlled transcription and translation of introduced genetic constructs. An additional major issue is genetic stability. I will present and discuss recent progress in our development of genetic tools for advanced cyanobacterial biotechnology. Progress on understanding the electron pathways in native and engineered cyanobacterial enzymes and heterologous expression of non-native enymzes in cyanobacterial cells will be highlighted. Finally, I will discuss our attempts to merge synthetic biology with synthetic chemistry to explore fundamantal questions of protein design and function.

  3. Beneficial clinical effects but limited tissue quality following osteochondral repair with a cell-free multilayered nano-composite scaffold in the talus.

    Science.gov (United States)

    Kaipel, Martin; Schreiner, Markus; Kellner, Richard; Klikovits, Joachim; Apprich, Sebastian; Brix, Martin; Boszotta, Harald; Domayer, Stephan; Trattnig, Siegfried

    2017-12-01

    The treatment of larger osteochondral lesions of the talus remains an operative challenge. In addition to micro fracturing and osteochondral transplantation one promising strategy could be the operative repair with a cell-free multilayered nano-composite scaffold with the potential to regenerate bone and cartilage in one treatment. In this prospective case series four consecutive patients who suffered from a single osteochondral lesion (≥1.5cm2) on the medial talus were enrolled. The repair potential of the implant was assessed using MRI based biochemical, compositional MR sequences (T2 mapping) as well as semi-quantitative morphological analyses (MOCART score) at 18 months follow-up after the surgery. The clinical outcome was determined at 6-, 12-, 18-, and 24 months follow-up by using the Ankle Disability Index and the AOFAS score. At 18 months after the surgery, the clinical outcome was significantly improved compared to the preoperative baseline. Global T2 relaxation times of the repair tissue were significantly increased compared to the healthy control cartilage. Osteochondral repair with a cell-free, biomimetic scaffold provides good clinical, short-term results. However, biochemical MR imaging provides strong evidence for limited repair tissue quality at 18 months after the implantation. IV. Copyright © 2016 European Foot and Ankle Society. Published by Elsevier Ltd. All rights reserved.

  4. Formalin fixation affects equilibrium partitioning of an ionic contrast agent-microcomputed tomography (EPIC-μCT) imaging of osteochondral samples

    NARCIS (Netherlands)

    Benders, K.E.M.; Malda, J.; Saris, D.B.F.; Dhert, W.J.A.; Steck, R.; Hutmacher, D.W.; Klein, T.J.

    2010-01-01

    Osteoarthritis Cartilage. 2010 Dec;18(12):1586-91. Epub 2010 Oct 13. Formalin fixation affects equilibrium partitioning of an ionic contrast agent-microcomputed tomography (EPIC-μCT) imaging of osteochondral samples. Benders KE, Malda J, Saris DB, Dhert WJ, Steck R, Hutmacher DW, Klein TJ.

  5. Return to sports after arthroscopic debridement and bone marrow stimulation of osteochondral talar defects: a 5- to 24-year follow-up study

    NARCIS (Netherlands)

    van Eekeren, I. C. M.; van Bergen, C. J. A.; Sierevelt, I. N.; Reilingh, M. L.; van Dijk, C. N.

    2016-01-01

    Osteochondral defects (OCD) often have a severe impact on the quality of life due to deep ankle pain during and after weight bearing, which prevents young patients from leading an active life. Arthroscopic debridement and bone marrow stimulation are currently the gold standard treatment. The purpose

  6. Osteochondral defect repair using bilayered hydrogels encapsulating both chondrogenically and osteogenically pre-differentiated mesenchymal stem cells in a rabbit model

    NARCIS (Netherlands)

    Lam, J.; Lu, S.; Lee, E.J.; Trachtenberg, J.E.; Meretoja, V.V.; Dahlin, R.L.; van den Beucken, J.J.; Tabata, Y.; Wong, M.E.; Jansen, J.A.; Mikos, A.G.; Kasper, F.K.

    2014-01-01

    OBJECTIVE: To investigate the ability of cell-laden bilayered hydrogels encapsulating chondrogenically and osteogenically (OS) pre-differentiated mesenchymal stem cells (MSCs) to effect osteochondral defect repair in a rabbit model. By varying the period of chondrogenic pre-differentiation from 7

  7. Flexible custom designs for CMS DAQ

    CERN Document Server

    Arcidiacono, Roberta; Boyer, Vincent; Brett, Angela Mary; Cano, Eric; Carboni, Andrea; Ciganek, Marek; Cittolin, Sergio; Erhan, Samim; Gigi, Dominique; Glege, Frank; Gomez-Reino Garrido, Robert; Gulmini, Michele; Gutleber, Johannes; Jacobs, Claude; Maron, Gaetano; Meijers, Frans; Meschi, Emilio; Murray, Steven John; Oh, Alexander; Orsini, Luciano; Paus, Christoph; Petrucci, Andrea; Piedra Gomez, Jonatan; Pieri, Marco; Pollet, Lucien; Racz, Attila; Sakulin, Hannes; Schwick, Christoph; Sumorok, Konstanty; Suzuki, Ichiro; Tsirigkas, Dimitrios; Varela, Joao

    2006-01-01

    The CMS central DAQ system is built using commercial hardware (PCs and networking equipment), except for two components: the Front-end Readout Link (FRL) and the Fast Merger Module (FMM). The FRL interfaces the sub-detector specific front-end electronics to the central DAQ system in a uniform way. The FRL is a compact-PCI module with an additional PCI 64bit connector to host a Network Interface Card (NIC). On the sub-detector side, the data are written to the link using a FIFO-like protocol (SLINK64). The link uses the Low Voltage Differential Signal (LVDS) technology to transfer data with a throughput of up to 400 MBytes/s. The FMM modules collect status signals from the front-end electronics of the sub-detectors, merge and monitor them and provide the resulting signals with low latency to the first level trigger electronics. In particular, the throttling signals allow the trigger to avoid buffer overflows and data corruption in the front-end electronics when the data produced in the front-end exceeds the c...

  8. Internal Fixation of Unstable Osteochondritis Dissecans in the Skeletally Mature Knee with Metal Screws.

    Science.gov (United States)

    Barrett, Ian; King, Alexander H; Riester, Scott; van Wijnen, Andre; Levy, Bruce A; Stuart, Michael J; Krych, Aaron J

    2016-04-01

    Several bioabsorbable and metal options are available for internal fixation of an unstable osteochondritis dissecans (OCD) lesion, but currently there are little data on outcomes with metal headless compression screws in the adult knee. The purpose of this study was to determine (1) the radiographic healing rates, (2) midterm clinical outcomes, and (3) comparison between healed and unhealed OCD fragments after use of headless metal compression screws for the treatment of unstable OCD lesions in the knees of skeletally mature patients. Retrospective chart review for all skeletally mature patients who presented with unstable femoral condyle OCD lesions of the knee was conducted. All patients underwent open or arthroscopic reduction and internal fixation using headless metal compression screws. Preoperative and postoperative radiographs were reviewed with healing defined as radiographic evidence of union of the OCD progeny fragment with the condyle. Clinical outcome data were collected retrospectively using 3 validated outcome scores: International Knee Documentation Committee (IKDC), Knee Injury and Osteoarthritis Outcome Score (KOOS), and Marx. Twenty-two knees in 22 patients with a mean age of 21 years (range= 14-37 years) were followed for an average of 8.7 years (range = 2-22 years). Metal, headless, cannulated compression screws were used in all 22 cases. At a mean of 31 months postoperatively (range = 2-262), fragment union was observed in 18 knees (82%). The remaining 4 knees (18%) required loose fragment excision and hardware removal at a mean of 9 months (range = 2-16 months) postoperatively. Mean postoperative Marx score was 7 (range = 0-16), the mean postoperative IKDC score was 85 (range = 62-100), and mean KOOS scores included KOOS Pain (93; range = 69-100), KOOS Symptoms (86; range = 71-100), KOOS ADL (98; range = 90-100), KOOS Sports (82; range = 50-100), and KOOS QOL (76; range = 50-100). Headless metal compression screws provide a satisfactory union

  9. Results of Surgical Management of Osteochondritis Dissecans of the Ankle in the Pediatric and Adolescent Population.

    Science.gov (United States)

    Kramer, Dennis E; Glotzbecker, Michael P; Shore, Benjamin J; Zurakowski, David; Yen, Yi-Meng; Kocher, Mininder S; Micheli, Lyle J

    2015-01-01

    There is a paucity of published literature on operative management of osteochondritis dissecans (OCD) in the ankle in adolescents. This study seeks to elucidate patient and lesion characteristics associated with surgical success and failure as well as reporting functional outcomes. Retrospective chart review identified all patients aged 18 years old or younger surgically treated for OCD of the ankle at our institution from 2001 to 2010. This included 109 ankles in 100 patients (75 female, 25 male), mean age 14.3 ± 2.3 years (range, 7 to 18 y), with a median follow-up of 3.3 years (range, 1 to 10.8 y). Patient and lesion data, surgical procedure, clinical results, and complications were recorded. Postoperative radiographs were reviewed in 80 ankles. A return to sport survey and a Foot and Ankle Outcome Score (FAOS) was sent to all patients. Multivariate statistical analysis evaluated predictors of reoperation rate, Berndt and Harty clinical grade, and FAOS scores. Kaplan-Meier analysis was applied to determine freedom from reoperation. The OCD lesion was most commonly found on the medial talus (80, 73%). The most common procedures performed included transarticular drilling (59, 54%), fixation (22, 20%), and excision microfracture (27, 26%). The overall rate of reoperation was 27% (29/109). Berndt and Harty clinical grade was poor (33, 30%), fair (23, 21%), and good (53, 49%). Reoperation rates were significantly higher for OCD lesions in which postoperative radiographs had no change or looked worse (10/16, 63%) (P = 0.002). Thirty-six of 44 survey respondents (82%) were satisfied and 37 (84%) returned to sports at a median time of 6 months. Average FAOS score was 77 ± 18. Multiple linear regression confirmed that female sex and elevated body mass index were significant negative predictors for FAOS score. The reoperation rate following surgical intervention for OCD of the ankle is high. Females and those with a higher body mass index may have worse subjective

  10. Anconeus Muscle-Pedicle Bone Graft With Periosteal Coverage for Osteochondritis Dissecans of the Humeral Capitellum.

    Science.gov (United States)

    Shimada, Kozo; Temporin, Ko; Oura, Keiichiro; Tanaka, Hiroyuki; Noguchi, Ryosuke

    2017-09-01

    Treatment of advanced osteochondritis dissecans (OCD) of the capitellum is controversial, especially in moderate-sized lesions. To establish a treatment algorithm for capitellum OCD, we tried to determine the utility of and problems associated with anconeus muscle-pedicle bone graft with periosteal coverage (ABGP) for the treatment of moderate-sized articular OCD defects of the capitellum. Case series; Level of evidence, 4. According to our protocol for elbow OCD, 16 patients (15 males, 1 female; age range, 12-17 years; mean age, 14.4 years) with a moderate-sized OCD lesion of the humeral capitellum were treated with ABGP. All patients had a full-thickness, unstable OCD lesion that was 10 to 15 mm in diameter. Clinical results and postoperative images, including radiographs and magnetic resonance imaging (MRI), were evaluated at a mean follow-up of 31 months (range, 24-66 months). All but 1 patient had functional improvement after the procedure and returned to previous sporting activities within 6 months. One female patient needed 1 year for functional recovery due to development of postoperative chronic regional pain syndrome (CRPS). Two patients required additional surgery, including shaving of the protruding cartilage, and they returned to their previous level of activity. Mean arc of range of flexion-extension motion was 117° preoperatively and 129° at follow-up (P = .031). Mean elbow function as assessed with the clinical rating system of Timmerman and Andrews was 136 preoperatively and 186 at follow-up (P = .00012). Bony union of the graft as demonstrated by trabecular bone bridging on radiography was obtained within 3 months in all patients. Postoperative MRI was examined for 14 patients at 6 to 12 months after the procedure; the MRIs showed near-normal articular surface integrity in 9 of the 14 patients (64%) and underlying bony structure in 10 of the 14 patients (71%). Improvement after ABGP was obtained within 6 months in all except 1 patient, who

  11. The Reliability of Assessing Radiographic Healing of Osteochondritis Dissecans of the Knee.

    Science.gov (United States)

    Wall, Eric J; Milewski, Matthew D; Carey, James L; Shea, Kevin G; Ganley, Theodore J; Polousky, John D; Grimm, Nathan L; Eismann, Emily A; Jacobs, Jake C; Murnaghan, Lucas; Nissen, Carl W; Myer, Gregory D; Weiss, Jennifer; Edmonds, Eric W; Anderson, Allen F; Lyon, Roger M; Heyworth, Benton E; Fabricant, Peter D; Zbojniewicz, Andy

    2017-05-01

    The reliability of assessing healing on plain radiographs has not been well-established for knee osteochondritis dissecans (OCD). To determine the inter- and intrarater reliability of specific radiographic criteria in judging healing of femoral condyle OCD. Cohort study (Diagnosis); Level of evidence, 3. Ten orthopedic sports surgeons rated the radiographic healing of 30 knee OCD lesions at 2 time points, a minimum of 1 month apart. First, raters compared pretreatment and 2-year follow-up radiographs on "overall healing" and on 5 subfeatures of healing, including OCD boundary, sclerosis, size, shape, and ossification using a continuous slider scale. "Overall healing" was also rated using a 7-tier ordinal scale. Raters then compared the same 30 pretreatment knee radiographs in a stepwise progression to the 2-, 4-, 7-, 12-, and 24-month follow-up radiographs on "overall healing" using a continuous slider scale. Interrater and intrarater reliability were assessed using intraclass correlations (ICC) derived from a 2-way mixed effects analysis of variance for absolute agreement. Overall healing of the OCD lesions from pretreatment to 2-year follow-up radiographs was rated with excellent interrater reliability (ICC = 0.94) and intrarater reliability (ICC = 0.84) when using a continuous scale. The reliability of the 5 subfeatures of healing was also excellent (interrater ICCs of 0.87-0.89; intrarater ICCs of 0.74-0.84). The 7-tier ordinal scale rating of overall healing had lower interrater (ICC = 0.61) and intrarater (ICC = 0.68) reliability. The overall healing of OCD lesions at the 5 time points up to 24 months had interrater ICCs of 0.81-0.88 and intrarater ICCs of 0.65-0.70. Interrater reliability was excellent when judging the overall healing of OCD femoral condyle lesions on radiographs as well as on 5 specific features of healing on 2-year follow-up radiographs. Continuous scale rating of OCD radiographic healing yielded higher reliability than the ordinal scale

  12. Return to Sport and Recreational Activity After Osteochondral Allograft Transplantation in the Knee.

    Science.gov (United States)

    Nielsen, E Scott; McCauley, Julie C; Pulido, Pamela A; Bugbee, William D

    2017-06-01

    Osteochondral allograft (OCA) transplantation is an integral part of the cartilage repair paradigm, but insufficient data are available regarding return to sport or recreational activity after the procedure. The purpose of this study was to determine if athletic patients undergoing OCA transplantation returned to sport, assess reasons for not returning to sport, and ascertain patient and graft-related characteristics that differed between those who returned or did not return to sport. The secondary aims were to assess graft survivorship and patient-reported subjective outcome measures (pain, function, satisfaction) among athletic patients undergoing OCA transplantation. Case series; Level of evidence, 4. We identified 149 knees in 142 patients who participated in sport or recreational activity before a cartilage injury (45% highly competitive athletes and 55% well-trained and frequently sporting) and underwent OCA transplantation in the knee. The mean age was 31.2 years and 58.4% were male. Information on preinjury and postoperative participation in sport or recreational activity was collected. Patients not returning to sport after OCA transplantation were mailed a questionnaire to assess why. Postoperative pain, function, and satisfaction scores were obtained, and further surgery on the operative knee was documented. At a mean follow-up of 6 years, 75.2% of knees returned to sport or recreational activity. Among those who did not return to sport, knee-related issues and lifestyle changes were cited as reasons why. Patients who did not return to sport were more likely to be female, have injured their knee in an activity other than sport, and have a larger graft size. The diagnosis and anatomic location also differed. Overall, 71% of knees reported having "very good" to "excellent" function, and 79% were able to participate in a high level of activity (moderate, strenuous, or very strenuous) postoperatively. After OCA transplantation, 25.5% of knees underwent

  13. Effects of Autogenous Bone Marrow Aspirate Concentrate on Radiographic Integration of Femoral Condylar Osteochondral Allografts.

    Science.gov (United States)

    Oladeji, Lasun O; Stannard, James P; Cook, Cristi R; Kfuri, Mauricio; Crist, Brett D; Smith, Matthew J; Cook, James L

    2017-10-01

    Transplantation of fresh osteochondral allografts (OCAs) is an attractive treatment option for symptomatic articular cartilage lesions in young, healthy patients. Because the lack of OCA bone integration can be a cause of treatment failure, methods for speeding and enhancing OCA bone integration to mitigate this potential complication are highly desirable. To determine if autogenous bone marrow aspirate concentrate (BMC) treatment of large femoral condylar OCAs would be associated with superior radiographic OCA bone integration compared with nontreated allografts during the critical first 6 months after surgery. Cohort study; Level of evidence, 3. A review of patients enrolled in a prospective registry who were treated with transplantation of large OCAs to one or both femoral condyles at our institution from March 12, 2013 to March 14, 2016 was performed. Patients were stratified into 2 groups based on BMC treatment versus no BMC treatment; the treatment was nonrandomized and was rooted in a shift in practice and a continuing effort to optimize OCA transplantation at our institution. Patients were excluded if they did not have orthogonal view radiographs performed at 6 weeks, 3 months, and 6 months postoperatively. Each condyle undergoing OCA transplantation was assessed individually by an independent musculoskeletal radiologist, who was blinded to the treatment group and time point. OCAs were assessed with respect to graft integration (0%-100%; 0 = no integration, 100 = complete integration) and degree of sclerosis (0-3; 0 = normal, 1 = mild sclerosis, 2 = moderate sclerosis, and 3 = severe sclerosis) of the graft at each time point. This study identified 17 condyles in 15 patients who underwent OCA transplantation without BMC and 29 condyles in 22 patients who underwent OCA transplantation with BMC. The BMC group had significantly ( P = .033) higher graft integration scores at 6 weeks, 3 months, and 6 months after surgery. Graft sclerosis was significantly ( P

  14. Equine developmental orthopaedic diseases--a genome-wide association study of first phalanx plantar osteochondral fragments in Standardbred trotters.

    Science.gov (United States)

    Lykkjen, S; Dolvik, N I; McCue, M E; Rendahl, A K; Mickelson, J R; Røed, K H

    2013-12-01

    Palmar/plantar osteochondral fragments (POF) in fetlock joints commonly affect and influence the athletic performance of horses. In this study, we used the Equine SNP50 BeadChip® to perform a genome-wide association study of metatarsophalangeal POF in 176 Norwegian Standardbred trotter yearlings. Putative quantitative trait loci (QTL) for medial and/or lateral POF, and medial POF only were identified on ECA1, 2, 7, 9 and 31, whereas for lateral POF, only on ECA7, 11, 27 and X. The moderate number of QTL evidences a complex inheritance and suggests various genes controlling POF development in medial and lateral locations. © 2013 The Authors, Animal Genetics © 2013 Stichting International Foundation for Animal Genetics.

  15. Osteocondrite dissecante do joelho: diagnóstico e tratamento Osteochondritis dissecans of the knee: diagnosis and treatment

    Directory of Open Access Journals (Sweden)

    Luiz Aurélio Mestriner

    2012-10-01

    Full Text Available A osteocondrite dissecante (OCD é um processo patológico que atinge o osso subcondral do joelho em criança e adolescente (OCDJ e adultos jovens (OCDA com efeitos secundários sobre a cartilagem articular com dor, edema, possível formação de corpos livres e sintomas mecânicos, inclusive bloqueio articular. A OCD pode levar a alterações degenerativas precoces da articulação, quando não tratada. Este artigo apresenta uma revisão e atualização sobre o problema com ênfase especial no diagnóstico e tratamento. Este pode incluir os métodos conservadores que mostram resultados mais satisfatórios para a OCDJ e os vários métodos cirúrgicos que incluem: técnicas reparativas como a remoção isolada do fragmento, as perfurações ósseas e a fixação do fragmento osteocondral e as técnicas restaurativas como as microfraturas, o transplante osteocondral autólogo (mosaicoplastia, o implante autólogo de condrócitos e o aloenxerto osteocondral fresco, considerando a lesão estável ou instável e sua viabilidade, bem como a maturidade esquelética e localização do processo. Estudos recentes para a avaliação dos resultados dos vários tipos de tratamento demonstram a falta de estudos com níveis de evidência confiáveis e sugere-se maior número de análises multicêntricas, prospectivas, randomizadas e controladas para estabelecer melhores diretrizes para o manuseio da doença.Osteochondritis dissecans (OCD is a pathological process affecting the subchondral bone of the knee in children and adolescents with open growth plates (juvenile OCD and young adults with closed growth plates (adult OCD. It may lead to secondary effects on joint cartilage, such as pain, edema, possible formation of free bodies and mechanical symptoms, including joint locking. OCD may lead to degenerative changes may develop if left untreated. This article presents a review and update on this problem, with special emphasis on diagnosis and treatment. The

  16. Rehabilitation and return-to-sports activity after debridement and bone marrow stimulation of osteochondral talar defects.

    Science.gov (United States)

    van Eekeren, Inge C M; Reilingh, Mikel L; van Dijk, C Niek

    2012-10-01

    An osteochondral defect (OD) is a lesion involving the articular cartilage and the underlying subchondral bone. ODs of the talus can severely impact on the quality of life of patients, who are usually young and athletic. The primary treatment for ODs that are too small for fixation, consists of arthroscopic debridement and bone marrow stimulation. This article delineates levels of activity, determines times for return to activity and reviews the factors that affect rehabilitation after arthroscopic debridement and bone marrow stimulation of a talar OD. Articles for review were obtained from a search of the MEDLINE database up to January 2012 using the search headings 'osteochondral defects', 'bone marrow stimulation', 'sports/activity', 'rehabilitation', various other related factors and 'talus'. English-, Dutch- and German-language studies were evaluated.The review revealed that there is no consensus in the existing literature about rehabilitation times or return-to-sports activity times, after treatment with bone marrow stimulation of ODs in the talus. Furthermore, scant research has been conducted on these issues. The literature also showed that potential factors that aid rehabilitation could include youth, lower body mass index, smaller OD size, mobilization and treatment with growth factors, platelet-rich plasma, biphosphonates, hyaluronic acid and pulse electromagnetic fields. However, most studies have been conducted in vitro or on animals. We propose a scheme, whereby return-to-sports activity is divided into four phases of increasing intensity: walking, jogging, return to non-contact sports (running without swerving) and return to contact sports (running with swerving and collision). We also recommend that research, conducted on actual sportsmen, of recovery times after treatment of talar ODs is warranted.

  17. Osteochondral lesions in distal tarsal joints of Icelandic horses reveal strong associations between hyaline and calcified cartilage abnormalities.

    Science.gov (United States)

    Ley, C J; Ekman, S; Hansson, K; Björnsdóttir, S; Boyde, A

    2014-03-25

    Osteochondral lesions in the joints of the distal tarsal region of young Icelandic horses provide a natural model for the early stages of osteoarthritis (OA) in low-motion joints. We describe and characterise mineralised and non-mineralised osteochondral lesions in left distal tarsal region joint specimens from twenty-two 30 ±1 month-old Icelandic horses. Combinations of confocal scanning light microscopy, backscattered electron scanning electron microscopy (including, importantly, iodine staining) and three-dimensional microcomputed tomography were used on specimens obtained with guidance from clinical imaging. Lesion-types were described and classified into groups according to morphological features. Their locations in the hyaline articular cartilage (HAC), articular calcified cartilage (ACC), subchondral bone (SCB) and the joint margin tissues were identified and their frequency in the joints recorded. Associations and correlations between lesion-types were investigated for centrodistal joints only. In centrodistal joints the lesion-types HAC chondrocyte loss, HAC fibrillation, HAC central chondrocyte clusters, ACC arrest and ACC advance had significant associations and strong correlations. These lesion-types had moderate to high frequency in centrodistal joints but low frequencies in tarsometatarsal and talocalcaneal-centroquartal joints. Joint margin lesion-types had no significant associations with other lesion-types in the centrodistal joints but high frequency in both the centrodistal and tarsometatarsal joints. The frequency of SCB lesion-types in all joints was low. Hypermineralised infill phase lesion-types were detected. Our results emphasise close associations between HAC and ACC lesions in equine centrodistal joints and the importance of ACC lesions in the development of OA in low-motion compression-loaded equine joints.

  18. Two-Year Evaluation of Osteochondral Repair with a Novel Biphasic Graft Saturated in Bone Marrow in an Equine Model.

    Science.gov (United States)

    McCarrel, Taralyn M; Pownder, Sarah L; Gilbert, Susannah; Koff, Matthew F; Castiglione, Emme; Saska, Ryan A; Bradica, Gino; Fortier, Lisa A

    2017-10-01

    Objective To evaluate a biphasic cartilage repair device (CRD) for feasibility of arthroscopic implantation, safety, biocompatibility, and efficacy for long-term repair of large osteochondral defects. Methods The CRD was press-fit into defects (10 mm diameter, 10 mm deep) created in the femoral trochlea of 12 horses. In the contralateral limb, 10 mm diameter full-thickness chondral defects were treated with microfracture (MFX). Radiographs were obtained pre- and postoperatively, and at 4, 12, and 24 months. Repeat arthroscopy was performed at 4 and 12 months. Gross assessment, histology, mechanical testing, and magnetic resonance imaging (MRI) were performed at 24 months. Results The CRD was easily placed arthroscopically. There was no evidence of joint infection, inflammation, or degeneration. CRD-treated defects had significantly more sclerosis compared to MFX early ( P = 0.0006), but was not different at 24 months. CRD had better arthroscopic scores at 4 months compared to MFX ( P = 0.0069). At 24 months, there was no difference in repair tissue on histology or mechanical testing. Based on MRI, CRD repair tissue had less proteoglycan (deep P = 0.027, superficial P = 0.015) and less organized collagen (deep P = 0.028) compared to MFX. Cartilage surrounding MFX defects had more fissures compared to CRD. Conclusion The repair tissue formed after CRD treatment of a large osteochondral lesion is fibrocartilage similar to that formed in simple chondral defects treated with MFX. The CRD can be easily placed arthroscopically, is safe, and biocompatible for 24 months. The CRD results in improved early arthroscopic repair scores and may limit fissure formation in adjacent cartilage.

  19. Tissue engineering the mandibular condyle.

    Science.gov (United States)

    Wang, Limin; Detamore, Michael S

    2007-08-01

    Tissue engineering provides the revolutionary possibility for curing temporomandibular joint (TMJ) disorders. Although characterization of the mandibular condyle has been extensively studied, tissue engineering of the mandibular condyle is still in an inchoate stage. The purpose of this review is to provide a summary of advances relevant to tissue engineering of mandibular cartilage and bone, and to serve as a reference for future research in this field. A concise anatomical overview of the mandibular condyle is provided, and the structure and function of the mandibular condyle are reviewed, including the cell types, extracellular matrix (ECM) composition, and biomechanical properties. Collagens and proteoglycans are distributed heterogeneously (topographically and zonally). The complexity of collagen types (including types I, II, III, and X) and cell types (including fibroblast-like cells, mesenchymal cells, and differentiated chondrocytes) indicates that mandibular cartilage is an intermediate between fibrocartilage and hyaline cartilage. The fibrocartilaginous fibrous zone at the surface is separated from hyaline-like mature and hypertrophic zones below by a thin and highly cellular proliferative zone. Mechanically, the mandibular condylar cartilage is anisotropic under tension (stiffer anteroposteriorly) and heterogeneous under compression (anterior region stiffer than posterior). Tissue engineering of mandibular condylar cartilage and bone is reviewed, consisting of cell culture, growth factors, scaffolds, and bioreactors. Ideal engineered constructs for mandibular condyle regeneration must involve two distinct yet integrated stratified layers in a single osteochondral construct to meet the different demands for the regeneration of cartilage and bone tissues. We conclude this review with a brief discussion of tissue engineering strategies, along with future directions for tissue engineering the mandibular condyle.

  20. Establishing proof of concept: Platelet-rich plasma and bone marrow aspirate concentrate may improve cartilage repair following surgical treatment for osteochondral lesions of the talus

    Science.gov (United States)

    Smyth, Niall A; Murawski, Christopher D; Haleem, Amgad M; Hannon, Charles P; Savage-Elliott, Ian; Kennedy, John G

    2012-01-01

    Osteochondral lesions of the talus are common injuries in the athletic patient. They present a challenging clinical problem as cartilage has a poor potential for healing. Current surgical treatments consist of reparative (microfracture) or replacement (autologous osteochondral graft) strategies and demonstrate good clinical outcomes at the short and medium term follow-up. Radiological findings and second-look arthroscopy however, indicate possible poor cartilage repair with evidence of fibrous infill and fissuring of the regenerative tissue following microfracture. Longer-term follow-up echoes these findings as it demonstrates a decline in clinical outcome. The nature of the cartilage repair that occurs for an osteochondral graft to become integrated with the native surround tissue is also of concern. Studies have shown evidence of poor cartilage integration, with chondrocyte death at the periphery of the graft, possibly causing cyst formation due to synovial fluid ingress. Biological adjuncts, in the form of platelet-rich plasma (PRP) and bone marrow aspirate concentrate (BMAC), have been investigated with regard to their potential in improving cartilage repair in both in vitro and in vitro settings. The in vitro literature indicates that these biological adjuncts may increase chondrocyte proliferation as well as synthetic capability, while limiting the catabolic effects of an inflammatory joint environment. These findings have been extrapolated to in vitro animal models, with results showing that both PRP and BMAC improve cartilage repair. The basic science literature therefore establishes the proof of concept that biological adjuncts may improve cartilage repair when used in conjunction with reparative and replacement treatment strategies for osteochondral lesions of the talus. PMID:22816065

  1. Inactivation of Vhl in Osteochondral Progenitor Cells Causes High Bone Mass Phenotype and Protects Against Age-Related Bone Loss in Adult Mice

    Science.gov (United States)

    Weng, Tujun; Xie, Yangli; Huang, Junlan; Luo, Fengtao; Yi, Lingxian; He, Qifen; Chen, Di; Chen, Lin

    2014-01-01

    Previous studies have shown that disruption of von Hippel–Lindau gene (Vhl) coincides with activation of hypoxia-inducible factor α (HIFα) signaling in bone cells and plays an important role in bone development, homeostasis, and regeneration. It is known that activation of HIF1α signaling in mature osteoblasts is central to the coupling between angiogenesis and bone formation. However, the precise mechanisms responsible for the coupling between skeletal angiogenesis and osteogenesis during bone remodeling are only partially elucidated. To evaluate the role of Vhl in bone homeostasis and the coupling between vascular physiology and bone, we generated mice lacking Vhl in osteochondral progenitor cells (referred to as Vhl cKO mice) at postnatal and adult stages in a tamoxifen-inducible manner and changes in skeletal morphology were assessed by micro–computed tomography (µCT), histology, and bone histomorphometry. We found that mice with inactivation of Vhl in osteochondral progenitor cells at the postnatal stage largely phenocopied that of mice lacking Vhl in mature osteoblasts, developing striking and progressive accumulation of cancellous bone with increased microvascular density and bone formation. These were accompanied with a significant increase in osteoblast proliferation, upregulation of differentiation marker Runx2 and osteocalcin, and elevated expression of vascular endothelial growth factor (VEGF) and phosphorylation of Smad1/5/8. In addition, we found that Vhl deletion in osteochondral progenitor cells in adult bone protects mice from aging-induced bone loss. Our data suggest that the VHL-mediated signaling in osteochondral progenitor cells plays a critical role in bone remodeling at postnatal/adult stages through coupling osteogenesis and angiogenesis. © 2014 American Society for Bone and Mineral Research. PMID:23999831

  2. One-step surgical procedure for the treatment of osteochondral defects with adipose-derived stem cells in a caprine knee defect: a pilot study.

    Science.gov (United States)

    Jurgens, Wouter J F M; Kroeze, Robert Jan; Zandieh-Doulabi, Behrouz; van Dijk, Annemieke; Renders, Greetje A P; Smit, Theo H; van Milligen, Florine J; Ritt, Marco J P F; Helder, Marco N

    2013-08-01

    Regenerative therapies offer attractive alternatives for the treatment of osteochondral defects. Adipose-derived stromal vascular fraction (SVF) cells allow the development of one-step surgical procedures by their abundant availability and high frequency. In this pilot study we evaluated the in vivo safety, feasibility, and efficacy of this concept using scaffolds seeded with freshly isolated (SVF) or cultured adipose stem cells (ASCs), and compared these to their acellular counterparts. Osteochondral defects were created in medial condyles and trochlear grooves in knees of eight goats. Defects were filled with acellular collagen I/III scaffolds or scaffolds seeded with SVF cells or cultured ASCs. Osteochondral regeneration was evaluated after 1 and 4 months by macroscopy, immunohistochemistry, biomechanical analysis, microCT analysis, and biochemistry. After 1 month, no adverse effects were noted. Microscopic, but not macroscopic evaluation showed considerable yet not significant differences, with cell-loaded constructs showing more extensive regeneration. After 4 months, acellular constructs displayed increased regeneration, however, to a lesser degree than cell-treated constructs. The latter exhibited more extensive collagen type II, hyaline-like cartilage, and higher elastic moduli, and their glycosaminoglycan content in the cartilaginous layer better approached native tissue values. Moreover, their defect regions contained higher levels of regenerated, mature subchondral bone with more intense collagen type I staining. SVF cells tended to perform best on all parameters. In summary, this pilot study demonstrated the preclinical safety and feasibility of a one-step surgical procedure for osteochondral defect regeneration. Similar regeneration was found between freshly isolated SVF cells and cultured ASCs. Larger studies with longer follow-up are required to substantiate these findings.

  3. Autologous chondrocyte implantation for the treatment of chondral and osteochondral defects of the talus: a meta-analysis of available evidence.

    Science.gov (United States)

    Niemeyer, Philipp; Salzmann, Gian; Schmal, Hagen; Mayr, Hermann; Südkamp, Norbert P

    2012-09-01

    While autologous chondrocyte implantation (ACI) has become an established surgical treatment for cartilage defects of the knee, only little is known about the clinical outcome following ACI for chondral or osteochondral lesion of the ankle. To evaluate efficiency and effectiveness of ACI for talar lesions was aim of the present meta-analysis. An OVID-based literature search was performed to identify any published clinical studies on autologous chondrocyte implantation (ACI) for the treatment of pathologies of the ankle including the following databases: MEDLINE, MEDLINE preprints, EMBASE, CINAHL, Life Science Citations, British National Library of Health, and Cochrane Central Register of Controlled Trials (CENTRAL). Literature search period was from the beginning of 1994 to February 2011. Of 54 studies that were identified, a total of 16 studies met the inclusion criteria of the present meta-analysis. Those studies were systematically evaluated. All studies identified represented case series (EBM Leven IV). 213 cases with various treatment for osteochondral and chondral defects with a mean size of 2.3 cm(2) (±0.6) have been reported. A total of 9 different scores have been used as outcome parameters. Mean study size was 13 patients (SD 10; range 2-46) with a mean follow-up of 32 ± 27 months (range 6-120). Mean Coleman Methodology Score was 65 (SD 11) points. Overall clinical success rate was 89.9%. Evidence concerning the use of ACI for osteochondral and chondral defects of the talus is still elusive. Although clinical outcome as described in the studies available seems promising--with regard to a lack of controlled studies--a superiority or inferiority to other techniques such as osteochondral transplantation or microfracturing cannot be estimated.

  4. Cartilage storage at 4 °C with regular culture medium replacement benefits chondrocyte viability of osteochondral grafts in vitro.

    Science.gov (United States)

    Qi, Jianhong; Hu, Zunjie; Song, Hongqiang; Chen, Bin; Xie, Di; Zhou, Lu; Zhang, Yanming

    2016-09-01

    Maintenance of articular cartilage allografts in culture media is a common method of tissue storage; however, the technical parameters of graft storage remain controversial. In this study, we examined the optimal temperature and culture medium exchange rate for the storage of osteochondral allografts in vitro. Cylindrical osteochondral grafts (n = 120), harvested from the talar joint surface of ten Boer goats, were randomly classified into four groups and stored under the following conditions: Group A1 was maintained at 4 °C in culture medium that was refreshed every 2 days; Group A2 was maintained at 4 °C in the same culture medium, without refreshing; Group B1, was maintained at 37 °C in culture medium that was refreshed every 2 days; Group B2, was maintained at 37 °C in the same culture medium, without refreshing. Chondrocyte viability in the grafts was determined by ethidium bromide/fluorescein diacetate staining on days 7, 21, and 35. Proteoglycan content was measured by Safranin-O staining. Group A1 exhibited the highest chondrocyte survival rates of 90.88 %, 88.31 % and 78.69 % on days 7, 21, and 35, respectively. Safranin O staining revealed no significant differences between groups on days 21 and 35. These results suggest that storage of osteochondral grafts at 4 °C with regular culture medium replacement should be highly suitable for clinical application.

  5. Association of 3-Dimensional Cartilage and Bone Structure with Articular Cartilage Properties in and Adjacent to Autologous Osteochondral Grafts after 6 and 12 Months in a Goat Model

    Science.gov (United States)

    Chan, Elaine F.; Liu, I-Ling; Semler, Eric J.; Aberman, Harold M.; Simon, Timothy M.; Chen, Albert C.; Truncale, Kate G.

    2012-01-01

    Objective: The articular cartilage of autologous osteochondral grafts is typically different in structure and function from local host cartilage and thereby presents a remodeling challenge. The hypothesis of this study was that properties of the articular cartilage of trochlear autografts and adjacent femoral condyle are associated with the 3-dimensional (3-D) geometrical match between grafted and contralateral joints at 6 and 12 months after surgery. Design: Autografts were transferred unilaterally from the lateral trochlea (LT) to the medial femoral condyle (MFC) in adult Spanish goats. Operated and contralateral nonoperated joints were harvested at 6 and 12 months and analyzed by indentation testing, micro–computed tomography, and histology to compare 1) histological indices of repair, 2) 3-D structure (articular surface deviation, bone-cartilage interface deviation, cartilage thickness), 3) indentation stiffness, and 4) correlations between stiffness and 3-D structure. Results: Cartilage deterioration was present in grafts at 6 months and more severe at 12 months. Cartilage thickness and normalized stiffness of the operated MFC were lower than the nonoperated MFC within the graft and proximal adjacent host regions. Operated MFC articular surfaces were recessed relative to the nonoperated MFC and exhibited lower cartilage stiffness with increasing recession. Sites with large bone-cartilage interface deviations, both proud and recessed, were associated with recessed articular surfaces and low cartilage stiffness. Conclusion: The effectiveness of cartilage repair by osteochondral grafting is associated with the match of 3-D cartilage and bone geometry to the native osteochondral structure. PMID:24224069

  6. Engineered miniaturized models of musculoskeletal diseases.

    Science.gov (United States)

    Bersini, Simone; Arrigoni, Chiara; Lopa, Silvia; Bongio, Matilde; Martin, Ivan; Moretti, Matteo

    2016-09-01

    The musculoskeletal system is an incredible machine that protects, supports and moves the human body. However, several diseases can limit its functionality, compromising patient quality of life. Designing novel pathological models would help to clarify the mechanisms driving such diseases, identify new biomarkers and screen potential drug candidates. Miniaturized models in particular can mimic the structure and function of basic tissue units within highly controlled microenvironments, overcoming the limitations of traditional macroscale models and complementing animal studies, which despite being closer to the in vivo situation, are affected by species-specific differences. Here, we discuss the miniaturized models engineered over the past few years to analyze osteochondral and skeletal muscle pathologies, demonstrating how the rationale design of novel systems could provide key insights into the pathological mechanisms behind diseases of the musculoskeletal system. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Comparison of glenohumeral contact pressures and contact areas after glenoid reconstruction with latarjet or distal tibial osteochondral allografts.

    Science.gov (United States)

    Bhatia, Sanjeev; Van Thiel, Geoffrey S; Gupta, Deepti; Ghodadra, Neil; Cole, Brian J; Bach, Bernard R; Shewman, Elizabeth; Wang, Vincent M; Romeo, Anthony A; Verma, Nikhil N; Provencher, Matthew T

    2013-08-01

    Glenoid reconstruction with distal tibial allografts offers the theoretical advantage over Latarjet reconstruction of improved joint congruity and a cartilaginous articulation for the humeral head. Hypothesis/ To investigate changes in the magnitude and location of glenohumeral contact areas, contact pressures, and peak forces after (1) the creation of a 30% anterior glenoid defect and subsequent glenoid bone augmentation with (2) a flush Latarjet coracoid graft or (3) a distal tibial osteochondral allograft. It was hypothesized that the distal tibial bone graft would best normalize glenohumeral contact areas, contact pressures, and peak forces. Controlled laboratory study. Eight cadaveric shoulder specimens were dissected free of all soft tissues and randomly tested in 3 static positions of humeral abduction with a 440-N compressive load: 30°, 60°, and 60° of abduction with 90° of external rotation (ABER). Glenohumeral contact area, contact pressure, and peak force were determined sequentially using a digital pressure mapping system for (1) the intact glenoid, (2) the glenoid with a 30% anterior bone defect, and (3) the glenoid after reconstruction with a distal tibial allograft or a Latarjet bone block. Glenoid reconstruction with distal tibial allografts resulted in significantly higher glenohumeral contact areas than reconstruction with Latarjet bone blocks in 60° of abduction (4.87 vs. 3.93 cm2, respectively; P Latarjet reconstruction in the ABER position (2.39 vs. 2.61 N, respectively; P Latarjet reconstruction also followed this same pattern, but differences in contact areas and peak forces between the defect model and Latarjet reconstruction in the ABER position were not statistically significant (P > .05). Reconstruction of anterior glenoid bone defects with a distal tibial allograft may allow for improved joint congruity and lower peak forces within the glenohumeral joint than Latarjet reconstruction at 60° of abduction and the ABER position

  8. Frequency distribution of osteochondral fragmentation of the dorsoproximal articular surface of the proximal phalanx in racing Thoroughbreds in the UK.

    Science.gov (United States)

    Walsh, R; Smith, M R W; Wright, I M

    2017-12-12

    Osteochondral fragmentation of the dorsoproximal margin of the proximal phalanx is commonly recognised in racing Thoroughbreds. Frequency distribution has been documented in racing Thoroughbreds and Quarter Horses in the USA and in European Warmbloods but no data have been published from the UK. Concurrent intra-articular soft tissue lesions and radiographic accuracy of fragment distribution in racing Thoroughbreds have not previously been reported. To document frequency distribution of dorsoproximal fragmentation of the proximal phalanx in a UK population of racing Thoroughbreds and to compare this with published data. To document concurrent intra-articular lesions identified arthroscopically and radiographic accuracy of fragment distribution. A retrospective single centre-based, observational study. Surgical reports and radiographs of all racing Thoroughbreds that underwent arthroscopic surgery for removal of fragmentation from the dorsoproximal margin of the proximal phalanx at Newmarket Equine Hospital between 2011 and 2015 were reviewed. Two hundred and forty-two (85.8%) horses were in or being prepared for flat racing. Osteochondral fragmentation of the dorsoproximal aspect of the proximal phalanx was present in 428 fetlock joints of 282 horses, consisting of 194 (45.3%) left and 188 (43.9%) right metacarpophalangeal joints, and 20 (4.7%) left and 26 (6.1%) right metatarsophalangeal joints. Fragmentation was located dorsomedially in 316 (73.8%), dorsolaterally in 32 (7.5%) and biaxially in 80 (18.7%) joints. Concurrent soft tissue lesions were identified in 168 (39.3%) joints. Radiographic evidence of fragmentation was visible in 320 joints (74.8%). Limited numbers preclude conclusions with respect to yearlings and horses in jump race training. Dorsoproximal fragmentation of the proximal phalanx occurred most frequently medially and in the forelimbs. Sidedness was not demonstrated. Although similar to previously reported data, variance in limb distribution is

  9. Influence of Intra-Articular Administration of Trichostatin A on Autologous Osteochondral Transplantation in a Rabbit Model

    Directory of Open Access Journals (Sweden)

    Huacheng Hou

    2015-01-01

    Full Text Available Autologous osteochondral transplantation (AOT is a method for articular cartilage repair. However, several disadvantages of this method have been reported, such as transplanted cartilage degeneration and the lack of a connection between the grafted and adjacent cartilage tissues. To evaluate the effect of intra-articular administration of trichostatin A (TSA on AOT, we conducted a case control study in a rabbit model. International Cartilage Repair Society (ICRS macroscopic scores, the modified O’Driscoll histology scores, and real-time PCR were utilized to evaluate the results. At 4 weeks, both macroscopic and histological assessments showed that there was no significant difference between the TSA and control groups. However, the mean macroscopic and histological scores for the TSA-treated group were significantly higher than the scores for the control group at 12 weeks. TSA was shown to directly reduce collagen type II (COL2, aggrecan, matrix metalloproteinase (MMP, and a disintegrin and metalloproteinase domain with thrombospondin motifs 5 (ADAMTS-5 expression and to simultaneously repress the upregulation of MMP-3, MMP-9, and MMP-13 levels induced by interleukin 1β (IL-1β in chondrocytes. In conclusion, TSA protects AOT grafts from degeneration, which may provide a benefit in the repair of articular cartilage injury.

  10. Arthroscopic surgery for osteochondral fractures of the proximal phalanx of the metacarpophalangeal and metatarsophalangeal (fetlock) joints in horses.

    Science.gov (United States)

    Yovich, J V; McIlwraith, C W

    1986-02-01

    Arthroscopic surgery for osteochondral fractures of the proximal phalanx was performed on 74 fetlock joints of 63 horses for a total of 87 fractures during a 2-year period. The medial dorsal proximal aspect of the proximal phalanx of the forelimbs was most commonly involved (59 fractures), followed by the lateral aspect (26 fractures), and 2 fractures occurred in the fetlock joint of the right hindlimb. At surgery, 82 fragments were removed and 5 fragments that had healed or were embedded in the joint capsule were not removed. Of the fragments removed, 15 were fixed firmly to the proximal phalanx, 63 were easily movable by arthroscopic instruments (but had soft tissue attachments to the proximal phalanx), and 4 were floating free within the joint. Arthroscopic surgery allowed excellent visualization and appreciation of the attachments of fragments and their stage of healing. Horses returned to full race training at an average of 11 1/2 weeks (range, 6 to 24 weeks). Thirty eight of 46 horses (82.6%) with adequate postoperative follow-up returned to athletic performance at least equal to that before fetlock injury.

  11. Citrate cross-linked gels with strain reversibility and viscoelastic behavior accelerate healing of osteochondral defects in a rabbit model.

    Science.gov (United States)

    Ghosh, Paulomi; Rameshbabu, Arun Prabhu; Dhara, Santanu

    2014-07-22

    Most living tissues are viscoelastic in nature. Self-repair due to the dissipation of energy by reversible bonds prevents the rupture of the molecular backbone in these tissues. Recent studies, therefore, have aimed to synthesize biomaterials that approximate the mechanical performance of biological materials with self-recovery properties. We report an environmentally friendly method for the development of ionotropically cross-linked viscoelastic chitosan gels with a modulus comparable to that of living tissues. The strain recovery property was found to be highest for the gels with the lowest cross-linking density. The force-displacement curve showed significant hysteresis due to the presence of reversible bonds in the cross-linked gels. Nanoindentation studies demonstrated the creep phenomenon for the cross-linked chitosan gels. Creep, hysteresis, and plasticity index confirmed the viscoelastic behavior of the cross-linked gels. The viscoelastic gels were implanted at osteochondral defect sites to assess the tissue regeneration ability. In vivo results demonstrated early cartilage formation and woven bone deposition for defects filled with the gels compared to nontreated defects.

  12. Sports Activity After Reconstruction of Osteochondral Lesions of the Talus With Autologous Spongiosa Grafts and Autologous Matrix-Induced Chondrogenesis.

    Science.gov (United States)

    Wiewiorski, Martin; Werner, Lorenzo; Paul, Jochen; Anderson, Andrew E; Barg, Alexej; Valderrabano, Victor

    2016-10-01

    For the treatment of osteochondral lesions of the talus (OCLTs), autologous matrix-induced chondrogenesis (AMIC) is a safe 1-step procedure with good clinical and radiological results. However, data regarding postoperative sports activity after AMIC are limited. To identify significant factors influencing the rate of postoperative sports and recreational activities. Case series; Level of evidence, 4. The sports and recreational activities of 60 patients (mean age, 34.9 ± 11.5 years) undergoing the AMIC procedure were retrospectively analyzed at a mean of 46.9 ± 17.8 months (range, 24.5-87.0 months) postoperatively. The visual analog scale (VAS) for pain score, Tegner activity scale score, activity rating scale (ARS) score, and satisfaction with surgery outcomes were assessed. Corrective calcaneal osteotomy was performed in 38 of 60 (63.3%) patients. Ligament repair was performed in 41 of 60 (68.3%) patients. The mean VAS score improved significantly from 6.9 ± 1.6 points (range, 5-10 points) preoperatively to 2.3 ± 1.9 points (range, 0-6 points) at latest follow-up (P sports activity before the onset of symptoms became significantly lower at the time of surgery (from 95.0% to 53.3%; P sports frequency and the duration of sports activity was found postoperatively. Patients undergoing AMIC repair of an OCLT participate at a similar low postoperative sports and recreational activity level compared with the preoperative level. © 2016 The Author(s).

  13. Management of Hepple Stage V Osteochondral Lesion of the Talus with a Platelet-Rich Plasma Scaffold

    Directory of Open Access Journals (Sweden)

    Wenqi Gu

    2017-01-01

    Full Text Available There has been no consensus on the treatment or prognosis of Hepple stage V osteochondral lesions of the talus (OLTs, especially for lesions greater than 1.5 cm2 in size. The objective of this study was to investigate the clinical outcomes achieved upon application of a platelet-rich plasma (PRP scaffold with a cancellous bone autograft for Hepple stage V OLTs. Fourteen patients (mean age, 39 years were treated with a cancellous bone graft and a PRP scaffold between 2013 and 2015. The mean time to surgical treatment was 23.5 months. Ankle X-ray and magnetic resonance imaging were performed at the final follow-up. Functional outcomes were evaluated according to the Visual Analog Scale (VAS score, American Orthopaedic Foot and Ankle Society (AOFAS score, and Short Form 36 (SF-36 score. The range of motion (ROM of the ankle joint and complications also were recorded. Thirteen patients completed the full follow-up, with a mean follow-up duration of 18 months. MRI demonstrated the complete regeneration of subchondral bone and cartilage in all patients. The postoperative VAS, AOFAS ankle and hindfoot, and SF-36 scores were improved significantly (all P<0.001 without obvious complications. We suggest that, for the Hepple stage V OLTs, management with cancellous bone graft and PRP scaffold may be a safe and effective treatment.

  14. Regenerative treatment in osteochondral lesions of the talus: autologous chondrocyte implantation versus one-step bone marrow derived cells transplantation.

    Science.gov (United States)

    Buda, Roberto; Vannini, Francesca; Castagnini, Francesco; Cavallo, Marco; Ruffilli, Alberto; Ramponi, Laura; Pagliazzi, Gherardo; Giannini, Sandro

    2015-05-01

    Osteochondral lesions of the talus (OLT) usually require surgical treatment. Regenerative techniques for hyaline cartilage restoration, like autologous chondrocytes implantation (ACI) or bone marrow derived cells transplantation (BMDCT), should be preferred. The aim of this work is comparing two clusters with OLT, treated with ACI or BMDCT. Eighty patients were treated with regenerative techniques, 40 with ACI and 40 with BMDCT. The two groups were homogenous regarding age, lesion size and depth, previous surgeries, etiology of the lesion, subchondral bone graft, final follow-up and pre-operative AOFAS score. The two procedures were performed arthroscopically. The scaffold was a hyaluronic acid membrane in all the cases, loaded with previously cultured chondrocytes (ACI) or with bone marrow concentrated cells, harvested in the same surgical session (BMDCT). All the patients were clinically and radiologically evaluated, using MRI Mocart score and T2 mapping sequence. Clinical results were similar in both groups at 48 months. No statistically significant influence was reported after evaluation of all the pre-operative parameters. The rate of return to sport activity showed slightly better results for BMDCT than ACI. MRI Mocart score was similar in both groups. MRI T2 mapping evaluation highlighted a higher presence of hyaline like values in the BMDCT group, and lower incidence of fibrocartilage as well. To date, ACI and BMDCT showed to be effective regenerative techniques for the treatment of OLT. BMDCT could be preferred over ACI for the single step procedure, patients' discomfort and lower costs.

  15. Bioactive glass in tissue engineering

    Science.gov (United States)

    Rahaman, Mohamed N.; Day, Delbert E.; Bal, B. Sonny; Fu, Qiang; Jung, Steven B.; Bonewald, Lynda F.; Tomsia, Antoni P.

    2011-01-01

    This review focuses on recent advances in the development and use of bioactive glass for tissue engineering applications. Despite its inherent brittleness, bioactive glass has several appealing characteristics as a scaffold material for bone tissue engineering. New bioactive glasses based on borate and borosilicate compositions have shown the ability to enhance new bone formation when compared to silicate bioactive glass. Borate-based bioactive glasses also have controllable degradation rates, so the degradation of the bioactive glass implant can be more closely matched to the rate of new bone formation. Bioactive glasses can be doped with trace quantities of elements such as Cu, Zn and Sr, which are known to be beneficial for healthy bone growth. In addition to the new bioactive glasses, recent advances in biomaterials processing have resulted in the creation of scaffold architectures with a range of mechanical properties suitable for the substitution of loaded as well as non-loaded bone. While bioactive glass has been extensively investigated for bone repair, there has been relatively little research on the application of bioactive glass to the repair of soft tissues. However, recent work has shown the ability of bioactive glass to promote angiogenesis, which is critical to numerous applications in tissue regeneration, such as neovascularization for bone regeneration and the healing of soft tissue wounds. Bioactive glass has also been shown to enhance neocartilage formation during in vitro culture of chondrocyte-seeded hydrogels, and to serve as a subchondral substrate for tissue-engineered osteochondral constructs. Methods used to manipulate the structure and performance of bioactive glass in these tissue engineering applications are analyzed. PMID:21421084

  16. Pretreatment of periosteum with TGF-beta1 in situ enhances the quality of osteochondral tissue regenerated from transplanted periosteal grafts in adult rabbits.

    Science.gov (United States)

    Olivos-Meza, A; Fitzsimmons, J S; Casper, M E; Chen, Q; An, K-N; Ruesink, T J; O'Driscoll, S W; Reinholz, G G

    2010-09-01

    To compare the efficacy of in situ transforming growth factor-beta1 (TGF-beta1)-pretreated periosteum to untreated periosteum for regeneration of osteochondral tissue in rabbits. In the pretreatment group, 12 month-old New Zealand white rabbits received subperiosteal injections of 200 ng of TGF-beta1 percutaneously in the medial side of the proximal tibia, 7 days prior to surgery. Control rabbits received no treatment prior surgery. Osteochondral transverse defects measuring 5mm proximal to distal and spanning the entire width of the patellar groove were created and repaired with untreated or TGF-beta1-pretreated periosteal grafts. Post-operatively the rabbits resumed normal cage activity for 6 weeks. Complete filling of the defects with regenerated tissue was observed in both the TGF-beta1-pretreated and control groups with reformation of the original contours of the patellar groove. The total histological score (modified O'Driscoll) in the TGF-beta1-pretreated group, 20 (95% Confidence Interval (CI), 19-21), was significantly higher (P=0.0001) than the control group, 18 (16-19). The most notable improvements were in structural integrity and subchondral bone regeneration. No significant differences in glycosaminoglycan or type II collagen content, or equilibrium modulus were found between the surgical groups. The cambium of the periosteum regenerated at the graft harvest site was significantly thicker (P=0.0065) in the TGF-beta1-pretreated rabbits, 121 microm (94-149), compared to controls, 74 microm (52-96), after 6 weeks. This study demonstrates that in situ pretreatment of periosteum with TGF-beta1 improves osteochondral tissue regeneration at 6-weeks post-op compared to untreated periosteum in 12 month-old rabbits. Copyright 2010 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.

  17. Microfracture technique versus osteochondral autologous transplantation mosaicplasty in patients with articular chondral lesions of the knee: a prospective randomized trial with long-term follow-up

    OpenAIRE

    Ulstein, Svend; Årøen, Asbjørn; Røtterud, Jan Harald; Løken, Sverre; Engebretsen, Lars; Heir, Stig

    2014-01-01

    Purpose To compare long-term functional and radiological outcome following microfracture technique (MF) versus osteochondral autologous transplantation (OAT) mosaicplasty for treating focal chondral lesions of the knee. Methods Twenty-five patients (mean age 32.3 years, SD 7.7) with a full-thickness (International Cartilage Repair Society grade 3 or 4) chondral lesion of the articulating surface of the femur were randomized to either MF (n = 11) or OAT mosaicplasty (n = 14). At a median follo...

  18. Bone Cysts After Osteochondral Allograft Repair of Cartilage Defects in Goats Suggest Abnormal Interaction Between Subchondral Bone and Overlying Synovial Joint Tissues

    OpenAIRE

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

    2013-01-01

    The efficacy of osteochondral allografts (OCA) 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 12 months in vivo. The ob...

  19. NTRCI Legacy Engine Research and Development Project Final Technical Report

    Energy Technology Data Exchange (ETDEWEB)

    Smith-Holbert, Connie [National Transportation Research Center, Inc., Knoxville, TN (United States); Petrolino, Joseph [National Transportation Research Center, Inc., Knoxville, TN (United States); Watkins, Bart [Power Source Technologies Inc., Corvallis, OR (United States); Irick, David [Power Source Technologies Inc., Corvallis, OR (United States)

    2011-12-31

    The Legacy engine is a completely new design, transitional diesel engine, replacing the reciprocating engine with a rotary engine. The Legacy engine offers significant advances over conventional internal combustion engines in 1) power to weight ratio; 2) multiple fuel acceptance; 3) fuel economy; and 4) environmental compliance. These advances are achieved through a combination of innovative design geometry, rotary motion, aspiration simplicity, and manufacturing/part simplicity. The key technical challenge to the Legacy engine's commercialization, and the focus of this project, was the development of a viable roton tip seal. The PST concept for the roton tip seal was developed into a manufacturable design. The design was evaluated using a custom designed and fabricated seal test fixture and further refined. This design was incorporated into the GEN2.5A prototype and tested for achievable compression pressure. The Decision Point at the end of Phase 1 of the project (described below) was to further optimize the existing tip seal design. Enhancements to the tip seal design were incorporated into the GEN2.5B prototype and tested and evaluated using the iterative research strategy described below. Compression pressures adequate for compression ignition of diesel fuel were achieved, although not consistently in all combustion volumes. The variation in compression pressures was characterized versus design features. As the roton tip seal performance was improved, results pointed toward inadequate performance of the housing side seals. Enhancement of the housing side seal system was accomplished using a custom designed side seal test fixture. The design enhancements developed with the test fixture were also incorporated into the GEN2.5B prototype and tested and evaluated using the iterative research strategy described below. Finally, to simplify the requirements for the roton tip seals and to enhance the introduction and combustion of fuel, a flush-mount fuel injector

  20. Cartilage tissue engineering on the surface of a novel gelatin-calcium-phosphate biphasic scaffold in a double-chamber bioreactor.

    Science.gov (United States)

    Chang, Chih-Hung; Lin, Feng-Huei; Lin, Chien-Cheng; Chou, Cheng-Hung; Liu, Hwa-Chang

    2004-11-15

    Tissue engineering is a new approach to articular cartilage repair; however, the integration of the engineered cartilage into the host subchondral bone is a major problem in osteochondral injury. The aim of the present work, therefore, was to make a tissue-engineered osteochondral construct from a novel biphasic scaffold in a newly designed double-chamber bioreactor. This bioreactor was designed to coculture chondrocytes and osteoblasts simultaneously. The aim of this study was to prove that engineered cartilage could be formed with the use of this biphasic scaffold. The scaffold was constructed from gelatin and a calcium-phosphate block made from calcined bovine bone. The cartilage part of the scaffold had a uniform pore size of about 180 microm and approximate porosity of 75%, with the trabecular pattern preserved in the bony part of the scaffold. The biphasic scaffolds were seeded with porcine chondrocytes and cultured in a double-chamber bioreactor for 2 or 4 weeks. The chondrocytes were homogeneously distributed in the gelatin part of the scaffold, and secretion of the extracellular matrix was demonstrated histologically. The chondrocytes retained their phenotype after 4 weeks of culture, as proven immunohistochemically. After 4 weeks of culture, hyaline-like cartilage with lacuna formation could be clearly seen in the gelatin scaffold on the surface of the calcium phosphate. The results show that this biphasic scaffold can support cartilage formation on a calcium-phosphate surface in a double-chamber bioreactor, and it seems reasonable to suggest that there is potential for further application in osteochondral tissue engineering. (c) 2004 Wiley Periodicals, Inc.

  1. Developing a Customized Perfusion Bioreactor Prototype with Controlled Positional Variability in Oxygen Partial Pressure for Bone and Cartilage Tissue Engineering.

    Science.gov (United States)

    Lee, Poh Soo; Eckert, Hagen; Hess, Ricarda; Gelinsky, Michael; Rancourt, Derrick; Krawetz, Roman; Cuniberti, Gianaurelio; Scharnweber, Dieter

    2017-05-01

    Skeletal development is a multistep process that involves the complex interplay of multiple cell types at different stages of development. Besides biochemical and physical cues, oxygen tension also plays a pivotal role in influencing cell fate during skeletal development. At physiological conditions, bone cells generally reside in a relatively oxygenated environment whereas chondrocytes reside in a hypoxic environment. However, it is technically challenging to achieve such defined, yet diverse oxygen distribution on traditional in vitro cultivation platforms. Instead, engineered osteochondral constructs are commonly cultivated in a homogeneous, stable environment. In this study, we describe a customized perfusion bioreactor having stable positional variability in oxygen tension at defined regions. Further, engineered collagen constructs were coaxed into adopting the shape and dimensions of defined cultivation platforms that were precasted in 1.5% agarose bedding. After cultivating murine embryonic stem cells that were embedded in collagen constructs for 50 days, mineralized constructs of specific dimensions and a stable structural integrity were achieved. The end-products, specifically constructs cultivated without chondroitin sulfate A (CSA), showed a significant increase in mechanical stiffness compared with their initial gel-like constructs. More importantly, the localization of osteochondral cell types was specific and corresponded to the oxygen tension gradient generated in the bioreactor. In addition, CSA in complementary with low oxygen tension was also found to be a potent inducer of chondrogenesis in this system. In summary, we have demonstrated a customized perfusion bioreactor prototype that is capable of generating a more dynamic, yet specific cultivation environment that could support propagation of multiple osteochondral lineages within a single engineered construct in vitro. Our system opens up new possibilities for in vitro research on human

  2. Current treatment modalities of osteochondritis dissecans of the knee joint: results of a nation-wide German survey.

    Science.gov (United States)

    Jerosch, J; Hoffstetter, I; Reer, R

    1996-06-01

    In a nation-wide survey 350 knee surgeons were asked for their current diagnostic and treatment modalities in patients with osteochondritis dissecans (OD) of the knee joint: 255 questionnaires were analyzed. With respect to the different imaging techniques, standard xray studies were performed by all surgeons. Other techniques were used in the following decreasing order of preference: xray tomography, MRI, CT-scan, ultrasound, bone scan, and arthrography. The indication for surgery was primarily influenced by the standard xray, and secondarily by xray tomography, then by MRI, and CT-scan. Regarding cartilage-inducing treatment methods, Pridie drilling (antegrade) was by far predominant over abrasion arthroplasties and Beck drilling (retrograde). Cartilage or perichondrium transplantation was performed rarely. For fixation of a loose fragment most of the surgeons preferred "Ethipins" followed by screws and K wires. Only one-third of the surgeons used MRI as one of the first diagnostic tools, but a higher percentage of surgeons recommended MRI in special cases. Especially in young patients MRI was used as often as plain xray, whereas the use of MRI in older patients was remarkably reduced. Concerning treatment modalities, the majority of surgeons treated young patients with protection from weight bearing. For cartilage stabilization, "Ethipins" were preferred, whereas screws were rarely recommended. Approximately 25% of the physicians would not treat asymptomatic patients at all. Even patients with typical symptoms were not treated by less than 15% of the surgeons. In general, adults with OD still embedded in the cartilage bed are treated more aggressively. In cases with a loose body the cartilage-inducing procedures are preferred. Perichondrium or cartilage transplantations are only rarely performed.

  3. Horse–, training– and race–level risk factors for palmar/plantar osteochondral disease in the racing Thoroughbred

    Science.gov (United States)

    Pinchbeck, G L; Clegg, P D; Boyde, A; Barr, E D; Riggs, C M

    2013-01-01

    Reasons for performing study Palmar/plantar osteochondral disease (POD) is a common, debilitating condition in Thoroughbred racehorses; however, training- and racing-related factors associated with this disease are unknown. Objectives To determine horse-, racing- and training-related risk factors for POD. The general hypotheses were that early training and racing, and increased intensity of racing and training, lead to increased severity of POD. Methods The metacarpo/metatarsophalangeal joints of 164 Thoroughbred racehorses were examined at post mortem and graded for third metacarpal and metatarsal POD. The relationships between training- and racing-related factors and grade of POD in each condyle were determined using multilevel, multivariable, ordinal logistic regression models. Results A total of 1288 condyles were graded. Factors associated with higher grades of POD were the total lifetime number of races, an increase in gallop sessions in the previous season, racing before import to Hong Kong and an increase in the number of short (8–16 weeks) between-race intervals per season. Horses in their first racing season were more likely to have lower POD grades, while horses that had a long between-race interval (greater than 16 weeks) in the season prior to euthanasia were also more likely to have lower POD grades. Lower POD grades were significantly more likely as days since last race increased up to 400 days. Age at first race was not significantly associated with grade of POD. Conclusions and potential relevance Cumulative racing exposure and training intensity in the previous season were associated with higher grades of POD, supporting the hypothesis that the disease is due to repetitive loading. Longer between-race intervals and increased time since racing were associated with lower POD grades, which may indicate that lesions heal. Further work is required to enable optimisation of racing and training programmes to reduce the frequency and severity

  4. Horse-, training- and race-level risk factors for palmar/plantar osteochondral disease in the racing Thoroughbred.

    Science.gov (United States)

    Pinchbeck, G L; Clegg, P D; Boyde, A; Barr, E D; Riggs, C M

    2013-09-01

    Palmar/plantar osteochondral disease (POD) is a common, debilitating condition in Thoroughbred racehorses; however, training- and racing-related factors associated with this disease are unknown. To determine horse-, racing- and training-related risk factors for POD. The general hypotheses were that early training and racing, and increased intensity of racing and training, lead to increased severity of POD. The metacarpo/metatarsophalangeal joints of 164 Thoroughbred racehorses were examined at post mortem and graded for third metacarpal and metatarsal POD. The relationships between training- and racing-related factors and grade of POD in each condyle were determined using multilevel, multivariable, ordinal logistic regression models. A total of 1288 condyles were graded. Factors associated with higher grades of POD were the total lifetime number of races, an increase in gallop sessions in the previous season, racing before import to Hong Kong and an increase in the number of short (8-16 weeks) between-race intervals per season. Horses in their first racing season were more likely to have lower POD grades, while horses that had a long between-race interval (greater than 16 weeks) in the season prior to euthanasia were also more likely to have lower POD grades. Lower POD grades were significantly more likely as days since last race increased up to 400 days. Age at first race was not significantly associated with grade of POD. Cumulative racing exposure and training intensity in the previous season were associated with higher grades of POD, supporting the hypothesis that the disease is due to repetitive loading. Longer between-race intervals and increased time since racing were associated with lower POD grades, which may indicate that lesions heal. Further work is required to enable optimisation of racing and training programmes to reduce the frequency and severity of this disease. © 2012 EVJ Ltd.

  5. COMPARATIVE MACROSCOPIC STUDY OF OSTEOCHONDRAL DEFECTS PRODUCED IN FEMURS OF RABBITS REPAIRED WITH BIOPOLYMER GEL CANE SUGAR.

    Science.gov (United States)

    de Albuquerque, Paulo Cezar Vidal Carneiro; Dos Santos, Saulo Monteiro; de Andrade Aguiar, José Lamartine; Filho, Nicodemus Pontes; de Mello, Roberto José Vieira; Costa, Mariana Lúcia Correia Ramos; de Albuquerque Olbertz, Clarissa Miranda Carneiro; de Souza Almeida, Tarciana Mendonça; da Silva Santos, Alessandro Henrique; da Silva, Joacil Carlos

    2011-01-01

    To study the surface, coloring, consistency, continuity and healing of osteochondral defects produced in the femoral condyles of rabbits and filled with sugar cane biopolymer gel (SCBG), after 90, 120 and 180 days, and in comparison with a control group. Sixteen adult New Zealand white rabbits aged 6 to 7 months, weighing between 2 and 2.5 kg and without locomotor system abnormalities were studied. In all the animals, a defect was made in the femoral condyles of the right and left knees, measuring 3.2 mm in diameter and 4 mm in depth, using a trephine. The animals were divided into two groups: study group formed by the right knees, in which the medial and lateral condyles received implants of SCBG; and control group formed by the left knees, in which the medial and lateral condyles were allowed to heal naturally. The knees were assessed 90, 120 and 180 days after the operation. After the animals had been sacrificed, the anatomical specimens were resected and placed in Bouin's solution. They were then photographed with a Nikon Coolpix 5400(®) coupled to a Nikon SM2800(®) stereoscopic loupe, to analyze the surface, coloring, consistency, continuity and healing. The results were evaluated using the chi-square test. There were no significant differences in the macroscopic assessments of healing between the study and control groups. With regard to the surface, coloring, consistency, continuity and healing of the defects, the macroscopic appearance of the tissue repaired with SCBG was similar to that of the control group.

  6. Assessment of strategies to increase chondrocyte viability in cryopreserved human osteochondral allografts: evaluation of the glycosylated hydroquinone, arbutin.

    Science.gov (United States)

    Rosa, S C; Gonçalves, J; Judas, F; Lopes, C; Mendes, A F

    2009-12-01

    Allogeneic cartilage is used to repair damaged areas of articular cartilage, requiring the presence of living chondrocytes. So far, no preservation method can effectively meet that purpose. Identification of more effective cryoprotective agents (CPAs) can contribute to this goal. The aim of this study was to determine whether the glycosylated hydroquinone, arbutin, alone or in combination with low concentrations of other CPAs, has cryoprotective properties towards human articular cartilage. Human tibial plateaus were procured from multi-organ donors, with the approval of the Ethics Committee of the University Hospital of Coimbra. The tibial plateaus were treated with or without arbutin (50 or 100mM), alone or in combination with various concentrations of dimethyl sulfoxide (DMSO) and glycerol, for 0.5-1.5h/37 degrees C, then frozen at -20 degrees C and 24h later transferred to a biofreezer at -80 degrees C. Two to 3 months later, thawing was achieved by immersion in cell culture medium at 37 degrees C/1h. Chondrocyte viability was assessed before and after freeze-thawing using a colorimetric assay based on the cell's metabolic activity and fluorescent dyes to evaluate cell membrane integrity. Before freezing, chondrocyte metabolic activity was identical in all the conditions tested. After freeze-thawing, the highest activity, corresponding to 34.2+/-2.1% of that in the Fresh Control, was achieved in tibial plateaus incubated in 50mM arbutin for 1h whereas in those left untreated it was 11.1+/-4.7. Addition of DMSO and glycerol to arbutin did not increase chondrocyte viability any further. Fluorescence microscopy confirmed these results and showed that living chondrocytes were mainly restricted to the superficial cartilage layers. Arbutin seems to be an effective cryoprotective agent for osteochondral allografts with potential benefits over DMSO and glycerol.

  7. Trans-species Engineering of Glycosylated Therapeutic Proteins

    DEFF Research Database (Denmark)

    Yang, Zhang

    understood. Currently, mammalian cells are required for human O-glycosylation. Increasing efforts have been devoted to engineering non-mammalian cells for production of recombinant proteins with “human-like” glycosylation. Substantial success has been achieved with designed N-glycosylation in both lower...... eukaryotes and even prokaryotes. Insect and yeast cells produce O-glycosylation incompatible with use in humans, however recently the yeast Pichia was engineered to perform the first step of human-like O-glycosylation. This review provides an overview of past and current engineering efforts of N......- and Oglycosylation and addresses emerging novel promising platforms such as plants. Plants are safe and low-cost production organisms; they do not perform mammalian-type glycosylation by itself and are easily up-scalable. These features should make it possible to custom design and build capacity for human...

  8. Xenoimplantation of an Extracellular-Matrix-Derived, Biphasic, Cell-Scaffold Construct for Repairing a Large Femoral-Head High-Load-Bearing Osteochondral Defect in a Canine Model

    Directory of Open Access Journals (Sweden)

    Yang Qiang

    2014-01-01

    Full Text Available This study was aimed to develop an ECM-derived biphasic scaffold and to investigate its regeneration potential loaded with BM-MSCs in repair of large, high-load-bearing osteochondral defects of the canine femoral head. The scaffolds were fabricated using cartilage and bone ECM as a cartilage and bone layer, respectively. Osteochondral constructs were fabricated using induced BM-MSCs and the scaffold. Osteochondral defects (11 mm diameter × 10 mm depth were created on femoral heads of canine and treated with the constructs. The repaired tissue was evaluated for gross morphology, radiography, histological, biomechanics at 3 and 6 months after implantation. Radiography revealed that femoral heads slightly collapsed at 3 months and severely collapsed at 6 months. Histology revealed that some defects in femoral heads were repaired, but with fibrous tissue or fibrocartilage, and femoral heads with different degrees of collapse. The bone volume fraction was lower for subchondral bone than normal femoral bone at 3 and 6 months. Rigidity was lower in repaired subchondral bone than normal femoral bone at 6 months. The ECM-derived, biphasic scaffold combined with induced BM-MSCs did not successfully repair large, high-load-bearing osteochondral defects of the canine femoral head. However, the experience can help improve the technique of scaffold fabrication and vascularization.

  9. Profile of serum alkaline phosphatase after inoculation of mononuclear cells and bone morphogenetic protein in the repair of osteochondral defects in rabbits

    Directory of Open Access Journals (Sweden)

    Luiz Augusto de Souza

    2011-12-01

    Full Text Available In this study, serum alkaline phosphatase activity was measured in response to the repair of osteochondral defects in twenty-four New Zealand rabbits. The animals were divided into three groups: a control (GC, those treated with bone marrow mononuclear cells (GCM and those that received mononuclear cells with autologous bone morphogenetic protein (BMP + GCM. After exposing the trochlear groove of the left stifle joint, a wedge-shaped segment was removed. Later, the defect was filled with an osteochondral autograft preserved in 98% glycerin. For the GC group, only the bone graft was performed. For the GCM, in addition to the graft, 2x106 seed mononuclear cells were implanted. For the GCM + BMP, the same number of cells, associated with 1μg of bone morphogenetic protein, were intraarticularly administered. The osteoblastic response was measured by analyzing the serum alkaline phosphatase on day 0 (preoperative 3, 15, 30, and 45 after surgery, and by radiographic examinations. Analysis of variance in randomized blocks, factorial and Tukey’s test (p = 0.05 were made. The overall mean GCM was superior to the other groups and the highest rates were among the 15th and 45th days postoperatively. The discrepancy in values between individuals of the same group casts doubts on the veracity of the test.

  10. Evaluation of osteochondral sample collection guided by computed tomography and magnetic resonance imaging for early detection of osteoarthritis in centrodistal joints of young Icelandic horses.

    Science.gov (United States)

    Ley, Charles J; Ekman, Stina; Dahlberg, Leif E; Björnsdóttir, Sigríður; Hansson, Kerstin

    2013-06-01

    To evaluate the use of CT and MRI for guidance of osteochondral sample collection for histologic detection of early osteoarthritic lesions in centrodistal (distal intertarsal) joints of horses. Right tarsal joints from the cadavers of 24 Icelandic horses aged 29 to 31 months. CT and MRI were used to evaluate the extent of suspected osteoarthritic changes in centrodistal joints, which were graded with a semiquantitative system. The anatomic regions with the highest grade of change were identified, and osteochondral samples were obtained from these regions. Samples were also obtained from the same centrodistal joints at predetermined sites. Histologic examination of all samples was performed, with samples classified as negative or positive for osteoarthritis, and results were compared between sample collection methods. Histologic examination revealed osteoarthritic lesions in 29% (7/24) of centrodistal joints with the predetermined method and in 63% (15/24) with the image-guided method. Significant associations were identified between histologic osteoarthritis detection and the summed image-guided sample collection site image grades, central osteophytes, articular cartilage thickness abnormalities, grade 2 articular mineralization front defects, and grade 2 marginal osteophytes. CT and MRI aided the detection of focal changes suggestive of early-stage osteoarthritis in the centrodistal joints of equine cadavers and may be useful for detection of similar disease in live horses. The first morphological changes of centrodistal joint osteoarthritis were suspected to be in the articular cartilage and the articular mineralization front regions.

  11. Recent Advances in Cartilage Tissue Engineering: From the Choice of Cell Sources to the Use of Bioreactors

    Science.gov (United States)

    Martin, Ivan; Démarteau, Olivier; Braccini, Alessandra

    Grafting engineered cartilage tissues represents a promising approach for the repair of joint injuries. Recent animal experiments have demonstrated that tissues engineered by culturing chondrocytes on 3D scaffolds in bioreactors provide functional templates for orderly repair of large osteochondral lesions. To date, however, a reproducible generation of uniform cartilage tissues of predefined size starting from adult human cells has not been achieved. In this paper we review some of the recent advances and challenges ahead in the identification of appropriate (i) cell sources, (ii) bioactive factors, (iii) 3D scaffolds and (iv) bioreactors for human cartilage tissue engineering. We also present an example of how integrated efforts in these different areas can help addressing fundamental questions and advancing the field of cartilage tissue engineering towards clinical use. The presented experiment demonstrates that human nasal chondrocytes are responsive to dynamic loading and thus could be further investigated as a cell source for implantation in a joint environment.

  12. Engineering Encounters: Engineering Adaptations

    Science.gov (United States)

    Gatling, Anne; Vaughn, Meredith Houle

    2015-01-01

    Engineering is not a subject that has historically been taught in elementary schools, but with the emphasis on engineering in the "Next Generation Science Standards," curricula are being developed to explicitly teach engineering content and design. However, many of the scientific investigations already conducted with students have…

  13. The potential of encapsulating "raw materials" in 3D osteochondral gradient scaffolds.

    Science.gov (United States)

    Mohan, Neethu; Gupta, Vineet; Sridharan, Banupriya; Sutherland, Amanda; Detamore, Michael S

    2014-04-01

    Scaffolds with continuous gradients in material composition and bioactive signals enable a smooth transition of properties at the interface. Components like chondroitin sulfate (CS) and bioactive glass (BG) in 3D scaffolds may serve as "raw materials" for synthesis of new extracellular matrix (ECM), and may have the potential to completely or partially replace expensive growth factors. We hypothesized that scaffolds with gradients of ECM components would enable superior performance of engineered constructs. Raw material encapsulation altered the appearance, structure, porosity, and degradation of the scaffolds. They allowed the scaffolds to better retain their 3D structure during culture and provided a buffering effect to the cells in culture. Following seeding of rat mesenchymal stem cells, there were several instances where glycosaminoglycan (GAG), collagen, or calcium contents were higher with the scaffolds containing raw materials (CS or BG) than with those containing transforming growth factor (TGF)-β3 or bone morphogenetic protein (BMP)-2. It was also noteworthy that a combination of both CS and TGF-β3 increased the secretion of collagen type II. Moreover, cells seeded in scaffolds containing opposing gradients of CS/TGF-β3 and BG/BMP-2 produced clear regional variations in the secretion of tissue-specific ECM. The study demonstrated raw materials have the potential to create a favorable microenvironment for cells; they can significantly enhance the synthesis of certain extracellular matrix (ECM) components when compared to expensive growth factors; either alone or in combination with growth factors they can enhance the secretion of tissue specific matrix proteins. Raw materials are promising candidates that can be used to either replace or be used in combination with growth factors. Success with raw materials in lieu of growth factors could have profound implications in terms of lower cost and faster regulatory approval for more rapid translation of

  14. Instruments for reproducible setting of defects in cartilage and harvesting of osteochondral plugs for standardisation of preclinical tests for articular cartilage regeneration.

    Science.gov (United States)

    Schwarz, Markus L; Schneider-Wald, Barbara; Brade, Joachim; Schleich, Dieter; Schütte, Andy; Reisig, Gregor

    2015-07-28

    Standardisation is required in research, so are approval procedures for advanced therapy medical products and other procedures for articular cartilage therapies. The process of creating samples needs to be reproducible. The aim of this study was to design, create and validate instruments (1) to create reproducible and accurate defects and (2) to isolate samples in the shape of osteochondral cylinders in a quick, reliable and sterile manner. Adjustable instruments were created: a crown mill with a resolution of 0.05 mm and a front mill to create defects in articular cartilage and subchondral bone. The instruments were tested on knee joints of pigs from the slaughterhouse; 48 defects were created and evaluated. A punching machine was designed to harvest osteochondral plugs. These were validated in an in vivo animal study. The instruments respect the desired depth of 0.5 and 1.5 mm when creating the defects, depending on whether the person using the instrument is highly experienced (0.451 mm; confidence interval (CI): 0.390 mm; 0.512 mm and 1.403 mm; CI: 1.305 mm; 1.502 mm) or less so (0.369 mm; CI: 0.297 mm; 0.440 mm and 1.241 mm; CI: 1.141 mm; 1.341 mm). Eighty samples were taken from knee joints of Göttingen Minipigs with this punching technique. The time needed for the harvesting of the samples was 7.52 min (±2.18 min), the parallelism of the sides of the cylinders deviated by -0.63° (CI: -1.33°; 0.08°) and the surface of the cartilage deviated from the perpendicularity by 4.86° (CI: 4.154°; 5.573°). In all assessed cases, a sterile procedure was observed. Instruments and procedures for standardised creation and validation of defects in articular cartilage and subchondral bone were designed. Harvesting of samples in the shape of osteochondral cylinders can now be performed in a quick, reliable and sterile manner. The presented instruments and procedures can serve as helpful steps towards standardised operating procedures in the field of

  15. The effect of sodium hyaluronate–chondroitin sulfate combined solution on cartilage formation in osteochondral defects of the rabbit knee: an experimental study

    Science.gov (United States)

    Tosun, Haci Bayram; Gürger, Murat; Gümüştaş, Seyit Ali; Uludag, Abuzer; Üçer, Özlem; Serbest, Sancar; Çelik, Suat

    2017-01-01

    Objective In focal cartilage lesions, multipotent mesenchymal stem cells in bone marrow are aimed to be moved into the defect area using subchondral drilling or microfracture method. However, repaired tissue insufficiently fills the defect area or cannot meet natural hyaline tissue functions, due to fibrous structure. We investigated the effect of a combined solution of sodium hyaluronate + chondroitin sulfate (HA+CS) administered intra-articularly after subchondral drilling on newly formed cartilage in rabbits with focal osteochondral defects. Materials and methods A total of 32 New Zealand White mature rabbits, whose weights ranged from 2.5 to 3 kg, were randomly divided into four groups. Full-thickness osteochondral defect was formed in the left-knee medial femur condyles of all rabbits. Subchondral drilling was then performed. The following treatment protocol was administered intra-articularly on knee joints on days 7, 14, and 21 after surgery: group 1, 0.3 mL combined solution of HA+CS (20 mg CS combined with 16 mg HA/mL); group 2, 0.3 mL HA (16 mg/mL); group 3, 0.3 mL CS (20 mg/mL); and group 4 (control group), 0.3 mL saline solution. In the sixth week, all animals were killed and then evaluated histopathologically and biochemically. Results There was significant articular cartilage formation in the HA+CS group compared to the HA, CS, and control groups. Hyaline cartilage formation was observed only in the HA+CS group. Cartilage-surface continuity and smoothness were significantly higher in the HA+CS and HA groups compared to the other groups. Normal cartilage mineralization was found to be significantly higher in the HA+CS group compared to the other groups. Increased levels of VEGFA and IL-1β in synovial fluid were observed in the HA+CS group. Conclusion After subchondral drilling, intra-articular HA-CS combination therapy is a good choice to promote better quality new cartilage-tissue formation in the treatment of focal osteochondral defects. PMID

  16. The effect of sodium hyaluronate-chondroitin sulfate combined solution on cartilage formation in osteochondral defects of the rabbit knee: an experimental study.

    Science.gov (United States)

    Tosun, Haci Bayram; Gürger, Murat; Gümüştaş, Seyit Ali; Uludag, Abuzer; Üçer, Özlem; Serbest, Sancar; Çelik, Suat

    2017-01-01

    In focal cartilage lesions, multipotent mesenchymal stem cells in bone marrow are aimed to be moved into the defect area using subchondral drilling or microfracture method. However, repaired tissue insufficiently fills the defect area or cannot meet natural hyaline tissue functions, due to fibrous structure. We investigated the effect of a combined solution of sodium hyaluronate + chondroitin sulfate (HA+CS) administered intra-articularly after subchondral drilling on newly formed cartilage in rabbits with focal osteochondral defects. A total of 32 New Zealand White mature rabbits, whose weights ranged from 2.5 to 3 kg, were randomly divided into four groups. Full-thickness osteochondral defect was formed in the left-knee medial femur condyles of all rabbits. Subchondral drilling was then performed. The following treatment protocol was administered intra-articularly on knee joints on days 7, 14, and 21 after surgery: group 1, 0.3 mL combined solution of HA+CS (20 mg CS combined with 16 mg HA/mL); group 2, 0.3 mL HA (16 mg/mL); group 3, 0.3 mL CS (20 mg/mL); and group 4 (control group), 0.3 mL saline solution. In the sixth week, all animals were killed and then evaluated histopathologically and biochemically. There was significant articular cartilage formation in the HA+CS group compared to the HA, CS, and control groups. Hyaline cartilage formation was observed only in the HA+CS group. Cartilage-surface continuity and smoothness were significantly higher in the HA+CS and HA groups compared to the other groups. Normal cartilage mineralization was found to be significantly higher in the HA+CS group compared to the other groups. Increased levels of VEGFA and IL-1β in synovial fluid were observed in the HA+CS group. After subchondral drilling, intra-articular HA-CS combination therapy is a good choice to promote better quality new cartilage-tissue formation in the treatment of focal osteochondral defects.

  17. A missense mutation in the aggrecan C-type lectin domain disrupts extracellular matrix interactions and causes dominant familial osteochondritis dissecans

    DEFF Research Database (Denmark)

    Stattin, Eva-Lena; Wiklund, Fredrik; Lindblom, Karin

    2010-01-01

    aggrecan (ACAN) as a prime candidate gene for the disorder. Sequence analysis of ACAN revealed heterozygosity for a missense mutation (c.6907G > A) in affected individuals, resulting in a p.V2303M amino acid substitution in the aggrecan G3 domain C-type lectin, which mediates interactions with other...... is produced and present in the tissue. Our results provide a molecular mechanism for the etiology of familial osteochondritis dissecans and show the importance of the aggrecan C-type lectin interactions for cartilage function in vivo....... proteins in the cartilage extracellular matrix. Binding studies with recombinant mutated and wild-type G3 proteins showed loss of fibulin-1, fibulin-2, and tenascin-R interactions for the V2303M protein. Mass spectrometric analyses of aggrecan purified from patient cartilage verified that V2303M aggrecan...

  18. PEO-PPO-PEO Carriers for rAAV-Mediated Transduction of Human Articular Chondrocytes in Vitro and in a Human Osteochondral Defect Model.

    Science.gov (United States)

    Rey-Rico, Ana; Frisch, Janina; Venkatesan, Jagadesh Kumar; Schmitt, Gertrud; Rial-Hermida, Isabel; Taboada, Pablo; Concheiro, Angel; Madry, Henning; Alvarez-Lorenzo, Carmen; Cucchiarini, Magali

    2016-08-17

    Gene therapy is an attractive strategy for the durable treatment of human osteoarthritis (OA), a gradual, irreversible joint disease. Gene carriers based on the small human adeno-associated virus (AAV) exhibit major efficacy in modifying damaged human articular cartilage in situ over extended periods of time. Yet, clinical application of recombinant AAV (rAAV) vectors remains complicated by the presence of neutralizing antibodies against viral capsid elements in a majority of patients. The goal of this study was to evaluate the feasibility of delivering rAAV vectors to human OA chondrocytes in vitro and in an experimental model of osteochondral defect via polymeric micelles to protect gene transfer from experimental neutralization. Interaction of rAAV with micelles of linear (poloxamer PF68) or X-shaped (poloxamine T908) poly(ethylene oxide) (PEO) and poly(propylene oxide) (PPO) copolymers (PEO-PPO-PEO micelles) was characterized by means of isothermal titration calorimetry. Micelle encapsulation allowed an increase in both the stability and bioactivity of rAAV vectors and promoted higher levels of safe transgene (lacZ) expression both in vitro and in experimental osteochondral defects compared with that of free vector treatment without detrimental effects on the biological activity of the cells or their phenotype. Remarkably, protection against antibody neutralization was also afforded when delivering rAAV via PEO-PPO-PEO micelles in all systems evaluated, especially when using T908. Altogether, these findings show the potential of PEO-PPO-PEO micelles as effective tools to improve current gene-based treatments for human OA.

  19. Validity of T2 mapping in characterization of the regeneration tissue by bone marrow derived cell transplantation in osteochondral lesions of the ankle

    Energy Technology Data Exchange (ETDEWEB)

    Battaglia, M., E-mail: milva.battaglia@ior.it [Service of Ecography and Radiology, Rizzoli Orthopaedic Institute, via Pupilli n. 1, 40136 Bologna (Italy); Rimondi, E. [Service of Ecography and Radiology, Rizzoli Orthopaedic Institute, via Pupilli n. 1, 40136 Bologna (Italy); Monti, C. [Service of CT and MRI, Casa di Cura Madre Fortunata Toniolo, Bologna (Italy); Guaraldi, F. [Department of Pathology, The Johns Hopkins University, School of Medicine, Baltimore, MD (United States); Sant' Andrea, A. [Service of CT and MRI, Casa di Cura Madre Fortunata Toniolo, Bologna (Italy); Buda, R.; Cavallo, M.; Giannini, S.; Vannini, F. [Clinical Orthopaedic and Traumatology Unit II, Rizzoli Orthopaedic Institute, Bologna (Italy)

    2011-11-15

    Objective: Bone marrow derived cell transplantation (BMDCT) has been recently suggested as a possible surgical technique to repair osteochondral lesions. To date, no qualitative MRI studies have evaluated its efficacy. The aim of our study is to investigate the validity of MRI T2-mapping sequence in characterizing the reparative tissue obtained and its ability to correlate with clinical results. Methods and materials: 20 patients with an osteochondral lesion of the talus underwent BMDCT and were evaluated at 2 years follow up using MRI T2-mapping sequence. 20 healthy volunteers were recruited as controls. MRI images were acquired using a protocol suggested by the International Cartilage Repair Society, MOCART scoring system and T2 mapping. Results were then correlated with AOFAS clinical score. Results: AOFAS score increased from 66.8 {+-} 14.5 pre-operatively to 91.2 {+-} 8.3 (p < 0.0005) at 2 years follow-up. T2-relaxation time value of 35-45 ms was derived from healthy ankles evaluation and assumed as normal hyaline cartilage value and used as a control. Regenerated tissue with a T2-relaxation time value comparable to hyaline cartilage was found in all the cases treated, covering a mean of 78% of the repaired lesion area. A high clinical score was related directly to isointense signal in DPFSE fat sat (p = 0.05), and percentage of regenerated hyaline cartilage (p = 0.05), inversely to the percentage of regenerated fibrocartilage. Lesion's depth negatively related to the integrity of the repaired tissue's surface (tau = -0.523, p = 0.007), and to the percentage of regenerated hyaline cartilage (rho = -0.546, p = 0.013). Conclusions: Because of its ability to detect cartilage's quality and to correlate to the clinical score, MRI T2-mapping sequence integrated with Mocart score represent a valid, non-invasive technique for qualitative cartilage assessment after regenerative surgical procedures.

  20. Engineering Encounters: Reverse Engineering

    Science.gov (United States)

    McGowan, Veronica Cassone; Ventura, Marcia; Bell, Philip

    2017-01-01

    This column presents ideas and techniques to enhance your science teaching. This month's issue shares information on how students' everyday experiences can support science learning through engineering design. In this article, the authors outline a reverse-engineering model of instruction and describe one example of how it looked in our fifth-grade…

  1. Engineer Ethics

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Dae Sik; Kim, Yeong Pil; Kim, Yeong Jin

    2003-03-15

    This book tells of engineer ethics such as basic understanding of engineer ethics with history of engineering as a occupation, definition of engineering and specialized job and engineering, engineer ethics as professional ethics, general principles of ethics and its limitation, ethical theory and application, technique to solve the ethical problems, responsibility, safety and danger, information engineer ethics, biotechnological ethics like artificial insemination, life reproduction, gene therapy and environmental ethics.

  2. Estudo macroscópico e histológico de reparos osteocondrais biologicamente aceitáveis Macroscopic and histological study of biologically acceptable osteochondral repairs

    Directory of Open Access Journals (Sweden)

    José Leão Ribeiro

    2004-03-01

    Full Text Available Este estudo teve como finalidade avaliar macroscopicamente e histológicamente defeitos osteocondrais já cicatrizados, também conhecidos como reparos. Foram utilizados seis coelhos machos, adultos, albinos da raça Nova Zelândia. Defeitos cilíndricos osteocondrais de 3.2 mm de diâmetro por 4.0 mm de profundidade foram criados cirurgicamente em ambos côndilos femorais mediais. O cilindro osteocondral retirado do joelho esquerdo (defeito não tratado foi implantado no joelho direito (joelho tratado. Comparou-se macroscopicamente e histológicamente ambos tipos de defeitos após doze semanas de evolução. A avaliação macroscópica de todos os defeitos mostrou evolução para reparos denominados biologicamente aceitáveis. O termo "biologicamente aceitável" foi utilizado para definir reparos, que à observação macroscópica, se apresentaram como tecido neo-formado semelhante à fibrocartilagem, brilhante, liso, firme, em continuidade com a cartilagem adjacente. Como todos os defeitos, tratados e não tratados, eram macroscopicamente semelhantes, realizou-se um estudo histológico comparativo para averiguar qual tipo de tecido de reparação se formava em ambos defeitos. Pela análise histológica dos reparos biologicamente aceitáveis, concluiu-se que houve formação de tecido cartilaginoso hialino nos defeitos tratados com enxerto autólogo e de tecido fibrocartilaginoso nos defeitos não tratados.The aim of this study was to evaluate macroscopically and histologically healed osteochondral defects, also known as repairs. Six adult, male, New Zealander White rabbits were used. Cylindrical osteochondral defects of 3.2 mm in diameter by 4.0 mm in depth were artificially created in the load-bearing surfaces of both medial femoral condyles. The osteochondral graft collected from the left knee (untreated defect was implanted in the right knee (treated defect. Both defects were compared macroscopically ad histologically after twelve weeks

  3. Biological and functional evaluation of a novel pyrolytic carbon implant for the treatment of focal osteochondral defects in the medial femoral condyle: assessment in a canine model.

    Science.gov (United States)

    Salkeld, Samantha L; Patron, Laura P; Lien, Joan C; Cook, Stephen D; Jones, Deryk G

    2016-12-01

    Osteochondral defects continue to be a clinical treatment challenge, and when left untreated, may cause pain and functional impairment. Pyrolytic carbon is a unique isotropic biomaterial used in heart valve and small joint replacements due to its excellent wear properties and biocompatibility with bone and articular cartilage. Therefore, a proposed solution is to utilize a focal pyrolytic carbon hemiarthroplasty implant as an alternative resurfacing treatment strategy for isolated cartilage lesions. A canine model (n = 9) was used to evaluate the in vivo histologic response and function of a pyrolytic carbon implant replacing a full-thickness osteochondral defect in the medial femoral condyle (MFC) of the knee. The gross appearance and histologic results were compared to an identical cobalt-chromium (Co-Cr) alloy implant placed in a defect in the contralateral MFC and evaluated up to 52 weeks. Extensive bone incorporation to the stem portion was observed for both implant types. The total mean histologic score for the cartilage of the MFC surrounding the pyrolytic carbon implants was significantly improved compared to that of the Co-Cr alloy implants at all evaluation periods (p < 0.05). Histologic grading and gross observations at 52 weeks for pyrolytic carbon implants were similar to those of Co-Cr alloy implants at 24 weeks. At 24 weeks, the mean total histologic score for Co-Cr alloy implants was 11.6 ± 0.7 (0-16 range point; 16 = normal appearance), while at 52 weeks, the mean total score for the pyrolytic carbon implants was 11.7 ± 1.3. Mean total histologic score of opposing medial tibia cartilage for the pyrolytic carbon implants was superior to that of the Co-Cr alloy group at all evaluation periods and significantly improved over the Co-Cr alloy implant group at 24 weeks (p = 0.001) and 52 weeks (p < 0.001). Use of a pyrolytic carbon implant for reconstruction of a focal cartilage defect demonstrated effective implant

  4. The Surgical Management of Osteochondritis Dissecans of the Knee in the Skeletally Immature: A Survey of the Pediatric Orthopaedic Society of North America (POSNA) Membership.

    Science.gov (United States)

    Yellin, Joseph L; Gans, Itai; Carey, James L; Shea, Kevin G; Ganley, Theodore J

    While the characteristics of osteochondritis dissecans (OCD) of the knee that require surgery to heal have been described, several surgical techniques/procedures exist with no consensus established regarding timing of treatment and specific surgical intervention. In this study, we aim to determine current trends in surgical treatment for OCD lesions in the skeletally immature who have failed 6 months of nonoperative management by surveying a large cohort of orthopaedic surgeons. An electronic survey designed using REDCap to capture surgeon treatment preferences for OCD lesions was distributed to members of the Pediatric Orthopaedic Society of North America (POSNA). The survey inquired about treating physicians' training and demographics. It then offered a series of clinical vignettes alongside imaging describing patients with varying degrees of severity of OCD following nonoperative treatment. Surgeons were prompted to select from a variety of multiple-choice-based options for further patient management. Standard descriptive statistics were used to summarize and compare the responses. Of the 129 POSNA members completing the pediatric survey, 97.7% were attending level orthopaedic surgeons, the majority identifying with an academic institution and treating mostly skeletally immature patients. In the skeletally immature population, the majority would treat intact, stable OCD lesions with drilling in a retroarticular or transarticular manner. Preferred treatment for unstable, salvageable lesions was screw fixation using bioabsorble materials or metal with variable pitch with no bone graft. The majority of respondents would treat unstable, unsalvageable OCD lesions with chondroplasty and osteochondral transplant/transfer or microfracture/drilling. The POSNA membership appears to agree on principle in terms of treatment modalities for various stages of OCD lesions in the skeletally immature, whereas individual techniques of achieving these principles may vary. Members

  5. Evolution of customization design for total knee arthroplasty.

    Science.gov (United States)

    Slamin, John; Parsley, Brian

    2012-12-01

    Total Knee Arthroplasty (TKA) is a highly successful surgical procedure with more than 600,000 TKA's performed annually in the US. Interest in improving surgical outcomes has led to improvements in surgical technique, instrumentation, and implant design. Computer navigation and robotic systems were introduced to further refine the mechanical alignment of joint replacement procedures. The cost to implement some of these technologies and the additional time required in the operating room to utilize these developments has limited the acceptance of them broadly. The introduction of custom instrumentation and cutting blocks based on computed tomography (CT) or magnetic resonance imaging (MRI) has allowed for better restoration of mechanical alignment. Unfortunately, little has changed in patient satisfaction in the past ten years. The recent introduction of patient specific instrumentation and patient specific implants is another step forward to restore the pre-deformity anatomy and joint geometry. This new technology can benefit the hospital by improving operating room time efficiencies through having shorter set-up times, and the elimination of cleaning, sterilization and inventory costs. The patient can potentially benefit by a shorter operative time, improved postoperative alignment and better fitting implants.

  6. Custom-designed nanomaterial libraries for testing metal oxide toxicity.

    Science.gov (United States)

    Pokhrel, Suman; Nel, André E; Mädler, Lutz

    2013-03-19

    Advances in aerosol technology over the past 10 years have enabled the generation and design of ultrafine nanoscale materials for many applications. A key new method is flame spray pyrolysis (FSP), which produces particles by pyrolyzing a precursor solution in the gas phase. FSP is a highly versatile technique for fast, single-step, scalable synthesis of nanoscale materials. New innovations in particle synthesis using FSP technology, including variations in precursor chemistry, have enabled flexible, dry synthesis of loosely agglomerated, highly crystalline ultrafine powders (porosity ≥ 90%) of binary, ternary, and mixed-binary-and-ternary oxides. FSP can fulfill much of the increasing demand, especially in biological applications, for particles with specific material composition, high purity, and high crystallinity. In this Account, we describe a strategy for creating nanoparticle libraries (pure or Fedoped ZnO or TiO₂) utilizing FSP and using these libraries to test hypotheses related to the particles' toxicity. Our innovation lies in the overall integration of the knowledge we have developed in the last 5 years in (1) synthesizing nanomaterials to address specific hypotheses, (2) demonstrating the electronic properties that cause the material toxicity, (3) understanding the reaction mechanisms causing the toxicity, and (4) extracting from in vitro testing and in vivo testing in terrestrial and marine organisms the essential properties of safe nanomaterials. On the basis of this acquired knowledge, we further describe how the dissolved metal ion from these materials (Zn²⁺ in this Account) can effectively bind with different cell constituents, causing toxicity. We use Fe-S protein clusters as an example of the complex chemical reactions taking place after free metal ions migrate into the cells. As a second example, TiO₂ is an active material in the UV range that exhibits photocatalytic behavior. The induction of electron-hole (e⁻/h⁺) pairs followed by free radical production is a key mechanism for biological injury. We show that decreasing the bandgap energy increases the phototoxicity in the presence of near-visible light. We present in detail the mechanism of electron transfer in biotic and abiotic systems during light exposure. Through this example we show that FSP is a versatile technique for efficiently designing a homologous library, meaning a library based on a parent oxide doped with different amounts of dopant, and investigating the properties of the resulting compounds. Finally, we describe the future outlook and state-of-the-art of an innovative two-flame system. A double-flame reactor enables independent control over each flame, the nozzle distances and the flame angles for efficient mixing of the particle streams. In addition, it allows for different flame compositions, flame sizes, and multicomponent mixing (a grain-grain heterojunction) during the reaction process.

  7. Custom design in lower limb prosthetics for athletic activity.

    Science.gov (United States)

    Fergason, J R; Boone, D A

    2000-08-01

    In summary, the prosthetist is the best source of information with regard to the fast-changing lower extremity prosthetics technology for sports. The needs and desires of the amputee should be outlined and balanced with the cost of the desired components and design. In many cases, one carefully designed prosthesis can serve in dual roles for everyday ambulation and certain athletic activities. In other cases, the amputee is limited severely by a prosthesis that is not designed for a specific activity. Using a prosthesis for activities that it was not designed to accommodate can cause physical injury to the amputee as well as structural failure of the device. A properly designed and fitted prosthesis can open a whole new world of activity to the amputee and helps him or her to reach the desired a vocational goals.

  8. Engineering ceramics

    CERN Document Server

    Bengisu, Murat

    2001-01-01

    This is a comprehensive book applying especially to junior and senior engineering students pursuing Materials Science/ Engineering, Ceramic Engineering and Mechanical Engineering degrees. It is also a reference book for other disciplines such as Chemical Engineering, Biomedical Engineering, Nuclear Engineering and Environmental Engineering. Important properties of most engineering ceramics are given in detailed tables. Many current and possible applications of engineering ceramics are described, which can be used as a guide for materials selection and for potential future research. While covering all relevant information regarding raw materials, processing properties, characterization and applications of engineering ceramics, the book also summarizes most recent innovations and developments in this field as a result of extensive literature search.

  9. In vivo experimental imaging of osteochondral defects and their healing using {sup 99m}Tc-NTP 15-5 radiotracer

    Energy Technology Data Exchange (ETDEWEB)

    Miot-Noirault, E.; Vidal, A.; Auzeloux, P.; Cachin, F.; Chezal, J.M. [Universite d' Auvergne, UMR 990 INSERM, Rue Montalembert, BP 184, 63005, Clermont-Ferrand Cedex (France); Guicheux, J.; Gauthier, O.; Lesoeur, J.; Vinatier, C. [Universite de Nantes, INSERM U791, STEP group ' ' Skeletal Tissue Engineering and Physiopathology' ' , Nantes (France); Askienazy, S. [Cyclopharma Laboratoires, Saint Beauzire (France)

    2012-07-15

    A rabbit model of osteochondral defects (OD) and spontaneous healing was longitudinally followed over 12 weeks, by in vivo joint scintigraphy using {sup 99m}Tc-NTP 15-5, and histology. We used two models, one with one OD (OD1 group) in the femoral condyle of one knee and the other with two ODs (OD2 group) in the femoral condyle of one knee, with the contralateral knees serving as the reference. A serial longitudinal imaging study was performed with the scintigraphic ratio (SR, operated knee uptake/contralateral knee uptake) determined at each time-point. ODs were imaged as radioactive defects. The SR was decreased with respective to controls, with values of 0.73 {+-} 0.08 and 0.65 {+-} 0.07 in the OD1 and OD2 groups, respectively, at 4 weeks after surgery. Histology of both OD groups revealed the presence of repair tissue characterized by a small amount of sulphated glycosaminoglycans and collagen. {sup 99m}Tc-NTP 15-5 imaging provided quantitative criteria useful for in vivo evaluation of cartilage trauma and healing. (orig.)

  10. Mechanical engineering

    CERN Document Server

    Darbyshire, Alan

    2010-01-01

    Alan Darbyshire's best-selling text book provides five-star high quality content to a potential audience of 13,000 engineering students. It explains the most popular specialist units of the Mechanical Engineering, Manufacturing Engineering and Operations & Maintenance Engineering pathways of the new 2010 BTEC National Engineering syllabus. This challenging textbook also features contributions from specialist lecturers, ensuring that no stone is left unturned.

  11. Repair of Osteochondral Defects Using Human Umbilical Cord Wharton's Jelly-Derived Mesenchymal Stem Cells in a Rabbit Model

    Science.gov (United States)

    Jia, Yanhui; Yuan, Mei; Guo, Weimin; Huang, Jingxiang; Zhao, Bin; Xu, Wenjing; Lu, Shibi

    2017-01-01

    Umbilical cord Wharton's jelly-derived mesenchymal stem cell (WJMSC) is a new-found mesenchymal stem cell in recent years with multiple lineage potential. Due to its abundant resources, no damage procurement, and lower immunogenicity than other adult MSCs, WJMSC promises to be a good xenogenous cell candidate for tissue engineering. This in vivo pilot study explored the use of human umbilical cord Wharton's jelly mesenchymal stem cells (hWJMSCs) containing a tissue engineering construct xenotransplant in rabbits to repair full-thickness cartilage defects in the femoral patellar groove. We observed orderly spatial-temporal remodeling of hWJMSCs into cartilage tissues during repair over 16 months, with characteristic architectural features, including a hyaline-like neocartilage layer with good surface regularity, complete integration with adjacent host cartilage, and regenerated subchondral bone. No immune rejection was detected when xenograft hWJMSCs were implanted into rabbit cartilage defects. The repair results using hWJMSCs were superior to those of chondrogenically induced hWJMSCs after assessing gross appearance and histological grading scores. These preliminary results suggest that using novel undifferentiated hWJMSCs as seed cells might be a better approach than using transforming growth factor-β-induced differentiated hWJMSCs for in vivo tissue engineering treatment of cartilage defects. hWJMSC allografts may be promising for clinical applications. PMID:28261617

  12. Matrix generation within a macroporous non-degradable implant for osteochondral defects is not enhanced with partial enzymatic digestion of the surrounding tissue: evaluation in an in vivo rabbit model.

    Science.gov (United States)

    Krych, Aaron J; Wanivenhaus, Florian; Ng, Kenneth W; Doty, Stephen; Warren, Russell F; Maher, Suzanne A

    2013-10-01

    Articular cartilage defects are a significant source of pain, have limited ability to heal, and can lead to the development of osteoarthritis. However, a surgical solution is not available. To tackle this clinical problem, non-degradable implants capable of carrying mechanical load immediately after implantation and for the duration of implantation, while integrating with the host tissue, may be viable option. But integration between articular cartilage and non-degradable implants is not well studied. Our objective was to assess the in vivo performance of a novel macroporous, nondegradable, polyvinyl alcohol construct. We hypothesized that matrix generation within the implant would be enhanced with partial digestion of the edges of articular cartilage. Our hypothesis was tested by randomizing an osteochondral defect created in the trochlea of 14 New Zealand white rabbits to treatment with: (i) collagenase or (ii) saline, prior to insertion of the implant. At 1 and 3-month post-operatively, the gross morphology and histologic appearance of the implants and the surrounding tissue were assessed. At 3 months, the mechanical properties of the implant were also quantified. Overall, the hydrogel implants performed favorably; at all time-points and in all groups the implants remained well fixed, did not cause inflammation or synovitis, and did not cause extensive damage to the opposing articular cartilage. Regardless of treatment with saline or collagenase, at 1 month post-operatively implants from both groups had a contiguous interface with adjacent cartilage and were populated with chondrocyte-like cells. At 3 months fibrous encapsulation of all implants was evident, there was no difference between area of aggrecan staining in the collagenase versus saline groups, and implant modulus was similar in both groups; leading us to reject our hypothesis. In summary, a porous PVA osteochondral implant remained well fixed in a short term in vivo osteochondral defect model

  13. Tip-Clearance Measurement in the First Stage of the Compressor of an Aircraft Engine.

    Science.gov (United States)

    García, Iker; Przysowa, Radosław; Amorebieta, Josu; Zubia, Joseba

    2016-11-11

    In this article, we report the design of a reflective intensity-modulated optical fiber sensor for blade tip-clearance measurement, and the experimental results for the first stage of a compressor of an aircraft engine operating in real conditions. The tests were performed in a ground test cell, where the engine completed four cycles from idling state to takeoff and back to idling state. During these tests, the rotational speed of the compressor ranged between 7000 and 15,600 rpm. The main component of the sensor is a tetrafurcated bundle of optical fibers, with which the resulting precision of the experimental measurements was 12 µm for a measurement range from 2 to 4 mm. To get this precision the effect of temperature on the optoelectronic components of the sensor was compensated by calibrating the sensor in a climate chamber. A custom-designed MATLAB program was employed to simulate the behavior of the sensor prior to its manufacture.

  14. Biochemical Engineering.

    Science.gov (United States)

    Dunnill, P.

    1979-01-01

    Biochemical engineering as a scientific discipline is becoming accepted in England and is drawing many young men and women to its ranks. This article focuses on how engineering came to embrace the biological sciences. (Author/SA)

  15. Engineering _ litteraturliste

    DEFF Research Database (Denmark)

    Sillasen, Martin Krabbe; Daugbjerg, Peer; Nielsen, Keld

    2017-01-01

    Litteraturliste udarbejdet som grundlag for artiklen ”Engineering – svaret på naturfagenes udfordringer?”......Litteraturliste udarbejdet som grundlag for artiklen ”Engineering – svaret på naturfagenes udfordringer?”...

  16. Governing Engineering

    DEFF Research Database (Denmark)

    Buch, Anders

    2011-01-01

    Abstract: Most people agree that our world faces daunting problems and, correctly or not, technological solutions are seen as an integral part of an overall solution. But what exactly are the problems and how does the engineering ‘mind set’ frame these problems? This chapter sets out to unravel...... dominant perspectives in challenge perception in engineering in the US and Denmark. Challenge perception and response strategies are closely linked through discursive practices. Challenge perceptions within the engineering community and the surrounding society are thus critical for the shaping...... of engineering education and the engineering profession. Through an analysis of influential reports and position papers on engineering and engineering education the chapter sets out to identify how engineering is problematized and eventually governed. Drawing on insights from governmentality studies the chapter...

  17. Governing Engineering

    DEFF Research Database (Denmark)

    Buch, Anders

    2012-01-01

    Most people agree that our world face daunting problems and, correctly or not, technological solutions are seen as an integral part of an overall solution. But what exactly are the problems and how does the engineering ‘mind set’ frame these problems? This chapter sets out to unravel dominant...... perspectives in challenge per-ception in engineering in the US and Denmark. Challenge perception and response strategies are closely linked through discursive practices. Challenge perceptions within the engineering community and the surrounding society are thus critical for the shaping of engineering education...... and the engineering profession. Through an analysis of influential reports and position papers on engineering and engineering education the chapter sets out to identify how engineering is problematized and eventually governed. Drawing on insights from governmentality studies the chapter strives to elicit the bodies...

  18. 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 ...

  19. Industrial Engineering

    DEFF Research Database (Denmark)

    Karlsson, Christer

    2015-01-01

    Industrial engineering is a discipline that is concerned with increasing the effectiveness of (primarily) manufacturing and (occasionally).......Industrial engineering is a discipline that is concerned with increasing the effectiveness of (primarily) manufacturing and (occasionally)....

  20. Genome editing with engineered nucleases in plants.

    Science.gov (United States)

    Osakabe, Yuriko; Osakabe, Keishi

    2015-03-01

    Numerous examples of successful 'genome editing' now exist. Genome editing uses engineered nucleases as powerful tools to target specific DNA sequences to edit genes precisely in the genomes of both model and crop plants, as well as a variety of other organisms. The DNA-binding domains of zinc finger (ZF) proteins were the first to be used as genome editing tools, in the form of designed ZF nucleases (ZFNs). More recently, transcription activator-like effector nucleases (TALENs), as well as the clustered regularly interspaced short palindromic repeats/Cas9 (CRISPR/Cas9) system, which utilizes RNA-DNA interactions, have proved useful. A key step in genome editing is the generation of a double-stranded DNA break that is specific to the target gene. This is achieved by custom-designed endonucleases, which enable site-directed mutagenesis via a non-homologous end-joining (NHEJ) repair pathway and/or gene targeting via homologous recombination (HR) to occur efficiently at specific sites in the genome. This review provides an overview of recent advances in genome editing technologies in plants, and discusses how these can provide insights into current plant molecular biology research and molecular breeding technology. © The Author 2014. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  1. Quantitative magnetic resonance imaging (MRI) evaluation of cartilage repair after microfracture (MF) treatment for adult unstable osteochondritis dissecans (OCD) in the ankle: correlations with clinical outcome

    Energy Technology Data Exchange (ETDEWEB)

    Tao, Hongyue; Lu, Rong; Feng, Xiaoyuan; Chen, Shuang [Fudan University, Department of Radiology, Huashan Hospital, Shanghai (China); Shang, Xiliang; Li, Hong; Hua, Yinghui [Fudan University, Department of Sports Medicine, Huashan Hospital, Shanghai (China)

    2014-08-15

    To quantitatively evaluate cartilage repair after microfracture (MF) for ankle osteochondritis dissecans (OCD) using MRI and analyse correlations between MRI and clinical outcome. Forty-eight patients were recruited and underwent MR imaging, including 3D-DESS, T2-mapping and T2-STIR sequences, and completed American Orthopaedic Foot and Ankle Society (AOFAS) scoring. Thickness index, T2 index of repair tissue (RT) and volume of subchondral bone marrow oedema (BME) were calculated. Subjects were divided into two groups: group A (3-12 months post-op), and group B (12-24 months post-op). Student's t test was used to compare the MRI and AOFAS score between two groups and Pearson's correlation coefficient to analyse correlations between them. Thickness index and AOFAS score of group B were higher than group A (P < 0.001, P < 0.001). T2 index and BME of group B were lower than group A (P < 0.001, P = 0.012). Thickness index, T2 index and BME were all correlated with AOFAS score (r = 0.416, r = -0.475, r = -0.353), but BME was correlated with neither thickness index nor T2 index. Significant improvement from MF can be expected on the basis of the outcomes of quantitative MRI and AOFAS score. MRI was correlated with AOFAS score. BME is insufficient as an independent predictor to evaluate repair quality, but reduction of BME can improve the patient's clinical outcome. (orig.)

  2. Effects of Pulsed Electromagnetic Fields on Return to Sports After Arthroscopic Debridement and Microfracture of Osteochondral Talar Defects: A Randomized, Double-Blind, Placebo-Controlled, Multicenter Trial.

    Science.gov (United States)

    Reilingh, Mikel L; van Bergen, Christiaan J A; Gerards, Rogier M; van Eekeren, Inge C; de Haan, Rob J; Sierevelt, Inger N; Kerkhoffs, Gino M M J; Krips, Rover; Meuffels, Duncan E; van Dijk, C N; Blankevoort, Leendert

    2016-05-01

    Osteochondral defects (OCDs) of the talus usually affect athletic patients. The primary surgical treatment consists of arthroscopic debridement and microfracture. Various possibilities have been suggested to improve the recovery process after debridement and microfracture. A potential solution to obtain this goal is the application of pulsed electromagnetic fields (PEMFs), which stimulate the repair process of bone and cartilage. The use of PEMFs after arthroscopic debridement and microfracture of an OCD of the talus leads to earlier resumption of sports and an increased number of patients that resume sports. Randomized controlled trial; Level of evidence, 1. A total of 68 patients were randomized to receive either PEMFs (n = 36) or placebo (n = 32) after arthroscopic treatment of an OCD of the talus. The primary outcomes (ie, the number of patients who resumed sports and time to resumption of sports) were analyzed with Kaplan-Meier curves as well as Mann-Whitney U, chi-square, and log-rank tests. Secondary functional outcomes were assessed with questionnaires (American Orthopaedic Foot and Ankle Society ankle-hindfoot score, Foot and Ankle Outcome Score, EuroQol, and numeric rating scales for pain and satisfaction) at multiple time points up to 1-year follow-up. To assess bone repair, computed tomography scans were obtained at 2 weeks and 1 year postoperatively. Almost all outcome measures improved significantly in both groups. The percentage of sport resumption (PEMF, 79%; placebo, 80%; P = .95) and median time to sport resumption (PEMF, 17 weeks; placebo, 16 weeks; P = .69) did not differ significantly between the treatment groups. Likewise, there were no significant between-group differences with regard to the secondary functional outcomes and the computed tomography results. PEMF does not lead to a higher percentage of patients who resume sports or to earlier resumption of sports after arthroscopic debridement and microfracture of talar OCDs. Furthermore, no

  3. Is there any difference between open and arthroscopic treatment for osteochondritis dissecans (OCD) of the humeral capitellum: a systematic review and meta-analysis.

    Science.gov (United States)

    Lu, Yi; Li, Yi Jun; Guo, Si Yi; Zhang, Hai Long

    2018-01-18

    We present a systematic review of the recent literatures regarding the arthroscopic and open technique in fragment fixation for osteochondritis dissecans (OCD) of the humeral capitellum and an analysis of the subjective and objective outcomes between these two procedures. PubMed and EMBASE were reviewed for suitable articles relating to fragment fixation for OCD, both open and arthroscopic. We included all studies reporting on the clinical outcomes of these two procedures that were published in the English language. Data extracted from each study included level of evidence, number of patients, surgical techniques, length of follow-up, clinical outcome measures including outcome scores, range of motion (ROM), return to sports, osseous union and complications. We analyzed each study to determine the primary outcome measurement. A total of ten studies met our inclusion criteria. Among all studies, 35 arthroscopic procedures and 107 open procedures were performed. After the procedure, 70 patients (86.4%) in the open group returned to their sports, and 32 patients (91.4%) in the arthroscopic group returned to their sports. In the arthroscopic group, patients gained 14.1 degrees of flexion and 9.5 degrees of extension after surgery. In the open group, patients gained 8 degrees of flexion and 5.7 degrees of extension. Five patients (4.7%) had complications in the open group. No complication was found in the arthroscopic group. Both open and arthroscopic lesion debridement with fragment fixation are successful in treating unstable OCD. The arthroscopic technique may be a better choice than the open procedure, but we need high-level evidence to determine the superiority of the open or arthroscopic techniques in treating elbow OCD. Level III.

  4. Engineering Motion

    Science.gov (United States)

    Tuttle, Nicole; Stanley, Wendy; Bieniek, Tracy

    2016-01-01

    For many teachers, engineering can be intimidating; teachers receive little training in engineering, particularly those teaching early elementary students. In addition, the necessity of differentiating for students with special needs can make engineering more challenging to teach. This article describes a professional development program…

  5. Smartphone-controlled optogenetically engineered cells enable semiautomatic glucose homeostasis in diabetic mice.

    Science.gov (United States)

    Shao, Jiawei; Xue, Shuai; Yu, Guiling; Yu, Yuanhuan; Yang, Xueping; Bai, Yu; Zhu, Sucheng; Yang, Linfeng; Yin, Jianli; Wang, Yidan; Liao, Shuyong; Guo, Sanwei; Xie, Mingqi; Fussenegger, Martin; Ye, Haifeng

    2017-04-26

    With the increasingly dominant role of smartphones in our lives, mobile health care systems integrating advanced point-of-care technologies to manage chronic diseases are gaining attention. Using a multidisciplinary design principle coupling electrical engineering, software development, and synthetic biology, we have engineered a technological infrastructure enabling the smartphone-assisted semiautomatic treatment of diabetes in mice. A custom-designed home server SmartController was programmed to process wireless signals, enabling a smartphone to regulate hormone production by optically engineered cells implanted in diabetic mice via a far-red light (FRL)-responsive optogenetic interface. To develop this wireless controller network, we designed and implanted hydrogel capsules carrying both engineered cells and wirelessly powered FRL LEDs (light-emitting diodes). In vivo production of a short variant of human glucagon-like peptide 1 (shGLP-1) or mouse insulin by the engineered cells in the hydrogel could be remotely controlled by smartphone programs or a custom-engineered Bluetooth-active glucometer in a semiautomatic, glucose-dependent manner. By combining electronic device-generated digital signals with optogenetically engineered cells, this study provides a step toward translating cell-based therapies into the clinic. Copyright © 2017, American Association for the Advancement of Science.

  6. Computational engineering

    CERN Document Server

    2014-01-01

    The book presents state-of-the-art works in computational engineering. Focus is on mathematical modeling, numerical simulation, experimental validation and visualization in engineering sciences. In particular, the following topics are presented: constitutive models and their implementation into finite element codes, numerical models in nonlinear elasto-dynamics including seismic excitations, multiphase models in structural engineering and multiscale models of materials systems, sensitivity and reliability analysis of engineering structures, the application of scientific computing in urban water management and hydraulic engineering, and the application of genetic algorithms for the registration of laser scanner point clouds.

  7. Architectural Engineers

    DEFF Research Database (Denmark)

    Petersen, Rikke Premer

    engineering is addresses from two perspectives – as an educational response and an occupational constellation. Architecture and engineering are two of the traditional design professions and they frequently meet in the occupational setting, but at educational institutions they remain largely estranged....... The paper builds on a multi-sited study of an architectural engineering program at the Technical University of Denmark and an architectural engineering team within an international engineering consultancy based on Denmark. They are both responding to new tendencies within the building industry where...... the role of engineers and architects increasingly overlap during the design process, but their approaches reflect different perceptions of the consequences. The paper discusses some of the challenges that design education, not only within engineering, is facing today: young designers must be equipped...

  8. Reduction of sample size requirements by bilateral versus unilateral research designs in animal models for cartilage tissue engineering.

    Science.gov (United States)

    Orth, Patrick; Zurakowski, David; Alini, Mauro; Cucchiarini, Magali; Madry, Henning

    2013-11-01

    Advanced tissue engineering approaches for articular cartilage repair in the knee joint rely on translational animal models. In these investigations, cartilage defects may be established either in one joint (unilateral design) or in both joints of the same animal (bilateral design). We hypothesized that a lower intraindividual variability following the bilateral strategy would reduce the number of required joints. Standardized osteochondral defects were created in the trochlear groove of 18 rabbits. In 12 animals, defects were produced unilaterally (unilateral design; n=12 defects), while defects were created bilaterally in 6 animals (bilateral design; n=12 defects). After 3 weeks, osteochondral repair was evaluated histologically applying an established grading system. Based on intra- and interindividual variabilities, required sample sizes for the detection of discrete differences in the histological score were determined for both study designs (α=0.05, β=0.20). Coefficients of variation (%CV) of the total histological score values were 1.9-fold increased following the unilateral design when compared with the bilateral approach (26 versus 14%CV). The resulting numbers of joints needed to treat were always higher for the unilateral design, resulting in an up to 3.9-fold increase in the required number of experimental animals. This effect was most pronounced for the detection of small-effect sizes and estimating large standard deviations. The data underline the possible benefit of bilateral study designs for the decrease of sample size requirements for certain investigations in articular cartilage research. These findings might also be transferred to other scoring systems, defect types, or translational animal models in the field of cartilage tissue engineering.

  9. Invisible Engineers

    Science.gov (United States)

    Ohashi, Hideo

    Questionnaire to ask “mention three names of scientists you know” and “three names of engineers you know” was conducted and the answers from 140 adults were analyzed. The results indicated that the image of scientists is represented by Nobel laureates and that of engineers by great inventors like Thomas Edison and industry founders like Soichiro Honda. In order to reveal the image of engineers among young generation, questionnaire was conducted for pupils in middle and high schools. Answers from 1,230 pupils were analyzed and 226 names mentioned as engineers were classified. White votes reached 60%. Engineers who are neither big inventors nor company founders collected less than 1% of named votes. Engineers are astonishingly invisible from young generation. Countermeasures are proposed.

  10. Engineering mechanics

    CERN Document Server

    Gross, Dietmar; Schröder, Jörg; Wall, Wolfgang A; Rajapakse, Nimal

    Statics is the first volume of a three-volume textbook on Engineering Mechanics. The authors, using a time-honoured straightforward and flexible approach, present the basic concepts and principles of mechanics in the clearest and simplest form possible to advanced undergraduate engineering students of various disciplines and different educational backgrounds. An important objective of this book is to develop problem solving skills in a systematic manner. Another aim of this volume is to provide engineering students as well as practising engineers with a solid foundation to help them bridge the gap between undergraduate studies on the one hand and advanced courses on mechanics and/or practical engineering problems on the other. The book contains numerous examples, along with their complete solutions. Emphasis is placed upon student participation in problem solving. The contents of the book correspond to the topics normally covered in courses on basic engineering mechanics at universities and colleges. Now in i...

  11. Information engineering

    Energy Technology Data Exchange (ETDEWEB)

    Hunt, D.N.

    1997-02-01

    The Information Engineering thrust area develops information technology to support the programmatic needs of Lawrence Livermore National Laboratory`s Engineering Directorate. Progress in five programmatic areas are described in separate reports contained herein. These are entitled Three-dimensional Object Creation, Manipulation, and Transport, Zephyr:A Secure Internet-Based Process to Streamline Engineering Procurements, Subcarrier Multiplexing: Optical Network Demonstrations, Parallel Optical Interconnect Technology Demonstration, and Intelligent Automation Architecture.

  12. Software engineering

    CERN Document Server

    Sommerville, Ian

    2010-01-01

    The ninth edition of Software Engineering presents a broad perspective of software engineering, focusing on the processes and techniques fundamental to the creation of reliable, software systems. Increased coverage of agile methods and software reuse, along with coverage of 'traditional' plan-driven software engineering, gives readers the most up-to-date view of the field currently available. Practical case studies, a full set of easy-to-access supplements, and extensive web resources make teaching the course easier than ever.

  13. Engineering knowledge

    OpenAIRE

    Nathan Rosenberg; W. Edward Steinmueller

    2013-01-01

    In historical perspective, both the nature of and arrangements for the generation of engineering knowledge have evolved over the past 150 years. We examine the historical development of the search for ‘useful knowledge’ in agriculture, aeronautics and chemical engineering during the first half of this period and the evolving balance between public and private initiative in supporting this search. During this period, the US was engaged in the engineering knowledge was often empirical, practice...

  14. Cognitive Engineering

    OpenAIRE

    Wilson, Kyle M.; Helton, William S.; Wiggins, Mark W.

    2013-01-01

    Cognitive engineering is the application of cognitive psychology and related disciplines to the design and operation of human–machine systems. Cognitive engineering combines both detailed and close study of the human worker in the actual work context and the study of the worker in more controlled environments. Cognitive engineering combines multiple methods and perspectives to achieve the goal of improved system performance. Given the origins of experimental psychology itself in issues regard...

  15. Engineering tribology

    CERN Document Server

    Stachowiak, Gwidon; Batchelor, A W; Batchelor, Andrew W

    2005-01-01

    As with the previous edition, the third edition of Engineering Tribology provides a thorough understanding of friction and wear using technologies such as lubrication and special materials. Tribology is a complex topic with its own terminology and specialized concepts, yet is vitally important throughout all engineering disciplines, including mechanical design, aerodynamics, fluid dynamics and biomedical engineering. This edition includes updated material on the hydrodynamic aspects of tribology as well as new advances in the field of biotribology, with a focus throughout on the engineering ap

  16. Concurrent arthroscopic osteochondral lesion treatment and lateral ankle ligament repair has no substantial effect on the outcome of chronic lateral ankle instability.

    Science.gov (United States)

    Jiang, Dong; Ao, Yin-Fang; Jiao, Chen; Xie, Xing; Chen, Lin-Xin; Guo, Qin-Wei; Hu, Yue-Lin

    2017-11-14

    The purpose of the study was to evaluate the effect of concurrent arthroscopic osteochondral lesion (OCL) treatment and lateral ankle ligament repair on the outcome of chronic lateral ankle instability. It was hypothesized that the arthroscopic OCL treatment might have some negative effect on the outcome of chronic lateral ankle instability (CLAI) by compromising the rehabilitation program. Ankle arthroscopy and anatomic lateral ankle ligament repair with suture anchors were performed for 70 patients with CLAI between 2010 and 2012. Thirty-four patients (group A), 20 males and 14 females with a median age of 30(14-54) years, received arthroscopic abrasion, curettage, drilling, or microfracture for OCLs. The splint was removed daily for joint motion exercises beginning at post-operative 2 weeks and full weight bearing was allowed between post-operative week 8 and 12. The other 36 patients (group B) with no combined OCL were followed up as controls. Pre-operative and post-operative visual analog scale (VAS) scores, American Orthopaedic Foot and Ankle Society (AOFAS) scores, Tegner scores, sprain recurrence, ankle stability, and range of motion (ROM) were evaluated and compared. The median follow-up was 46.5 (38-55) months and 44.5 (38-56) months for group A and group B, respectively. The median post-operative VAS score, AOFAS score, and Tegner score were improved from the pre-operative level for both groups with good-to-excellent results for more than 90% patients. No significant difference was found between the two groups for the subjective scores and satisfaction rate (n.s.). Recurrent sprain was found among nine patients(26.5%) of the group A and five patients (13.9%) of the group B (n.s.). The incidence of the ROM restriction of group A was significantly higher than in group B (23.5 vs 5.6%, P = 0.043). The concurrent arthroscopic treatment of OCL with lateral ankle ligament repair demonstrated no substantial negative effect on the overall mid-term outcome

  17. Hydroxyapatite-coated double network hydrogel directly bondable to the bone: Biological and biomechanical evaluations of the bonding property in an osteochondral defect.

    Science.gov (United States)

    Wada, Susumu; Kitamura, Nobuto; Nonoyama, Takayuki; Kiyama, Ryuji; Kurokawa, Takayuki; Gong, Jian Ping; Yasuda, Kazunori

    2016-10-15

    We have developed a novel hydroxyapatite (HAp)-coated double-network (DN) hydrogel (HAp/DN gel). The purpose of this study was to determine details of the cell and tissue responses around the implanted HAp/DN gel and to determine how quickly and strongly the HAp/DN gel bonds to the bone in a rabbit osteochondral defect model. Immature osteoid tissue was formed in the space between the HAp/DN gel and the bone at 2weeks, and the osteoid tissue was mineralized at 4weeks. The push-out load of the HAp/DN gel averaged 37.54N and 42.15N at 4 and 12weeks, respectively, while the push-out load of the DN gel averaged less than 5N. The bonding area of the HAp/DN gel to the bone was above 80% by 4weeks, and above 90% at 12weeks. This study demonstrated that the HAp/DN gel enhanced osseointegration at an early stage after implantation. The presence of nanoscale structures in addition to osseointegration of HAp promoted osteoblast adhesion onto the surface of the HAp/DN gel. The HAp/DN gel has the potential to improve the implant-tissue interface in next-generation orthopaedic implants such as artificial cartilage. Recent studies have reported the development of various hydrogels that are sufficiently tough for application as soft supporting tissues. However, fixation of hydrogels on bone surfaces with appropriate strength is a great challenge. We have developed a novel, tough hydrogel hybridizing hydroxyapatite (HAp/DN gel), which is directly bondable to the bone. The present study demonstrated that the HAp/DN gel enhanced osseointegration in the early stage after implantation. The presence of nanoscale structures in addition to the osseointegration ability of hydroxyapatite promoted osteoblast adhesion onto the surface of the HAp/DN gel. The HAp/DN gel has the potential to improve the implant-tissue interface in next-generation orthopaedic implants such as artificial cartilage. Copyright © 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  18. 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

  19. Lesion Size Is a Predictor of Clinical Outcomes After Bone Marrow Stimulation for Osteochondral Lesions of the Talus: A Systematic Review.

    Science.gov (United States)

    Ramponi, Laura; Yasui, Youichi; Murawski, Christopher D; Ferkel, Richard D; DiGiovanni, Christopher W; Kerkhoffs, Gino M M J; Calder, James D F; Takao, Masato; Vannini, Francesca; Choi, Woo Jin; Lee, Jin Woo; Stone, James; Kennedy, John G

    2017-06-01

    The critical lesion size treated with bone marrow stimulation (BMS) for osteochondral lesions of the talus (OLTs) has been 150 mm 2 in area or 15 mm in diameter. However, recent investigations have failed to detect a significant correlation between the lesion size and clinical outcomes after BMS for OLTs. To systematically review clinical studies reporting both the lesion size and clinical outcomes after BMS for OLTs. Systematic review. A systematic search of the MEDLINE and EMBASE databases was performed in March 2015 based on the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Included studies were evaluated with regard to the level of evidence (LOE), quality of evidence (QOE), lesion size, and clinical outcomes. Twenty-five studies with 1868 ankles were included; 88% were either LOE 3 or 4, and 96% did not have good QOE. The mean area was 103.8 ± 10.2 mm 2 in 20 studies, and the mean diameter was 10.0 ± 3.2 mm in 5 studies. The mean American Orthopaedic Foot and Ankle Society score improved from 62.4 ± 7.9 preoperatively to 83.9 ± 9.2 at a mean 54.1-month follow-up in 14 studies reporting both preoperative and postoperative scores with a mean follow-up of more than 2 years. A significant correlation was found in 3 studies, with a mean lesion area of 107.4 ± 10.4 mm 2 , while none was reported in 8 studies, with a mean lesion area of 85.3 ± 9.2 mm 2 . The lesion diameter significantly correlated with clinical outcomes in 2 studies (mean diameter, 10.2 ± 3.2 mm), whereas none was found in 2 studies (mean diameter, 8.8 ± 0.0 mm). However, the reported lesion size measurement method and evaluation method of clinical outcomes widely varied among the studies. An assessment of the currently available data does suggest that BMS may best be reserved for OLT sizes less than 107.4 mm 2 in area and/or 10.2 mm in diameter. Future development in legitimate prognostic size guidelines based on high-quality evidence that correlate

  20. Biosystems engineering

    OpenAIRE

    P. Ulger; E. Gonulol

    2015-01-01

    Higher agricultural education system has been getting multidiscipline as a result of the level oftechnology, recently. Biosystems Engineering has become popular in developed countries particularly afterelectronic and information technologies has been getting to be a part of agriculture and accompanied ofbiology. In this study definition of Biosystems Engineering discipline, working areas, research, publicationand job opportunities were discussed meticulously. Academic organization of Biosyste...

  1. Engineering Administration.

    Science.gov (United States)

    Naval Personnel Program Support Activity, Washington, DC.

    This book is intended to acquaint naval engineering officers with their duties in the engineering department. Standard shipboard organizations are analyzed in connection with personnel assignments, division operations, and watch systems. Detailed descriptions are included for the administration of directives, ship's bills, damage control, training…

  2. Engineering News

    OpenAIRE

    Nystrom, Lynn; Haugh, Lindsey; Simpkins, David

    2014-01-01

    Engineering News is the College of Engineering's annual newsletter sent to all alumni of the college. Virginia Tech leaders, along with counterparts in New Jersey, welcomed a late December approval by the Federal Aviation Administration to operate a test site to integrate unmanned aircraft into the national airspace.

  3. Food Engineering

    NARCIS (Netherlands)

    Boom, R.M.; Janssen, A.E.M.

    2014-01-01

    Food engineering is a rapidly changing discipline. Traditionally, the main focus was on food preservation and stabilization, whereas trends now are on diversity, health, taste, and sustainable production. Next to a general introduction of the definition of food engineering, this article gives a

  4. Corrosion Engineering.

    Science.gov (United States)

    White, Charles V.

    A description is provided for a Corrosion and Corrosion Control course offered in the Continuing Engineering Education Program at the General Motors Institute (GMI). GMI is a small cooperative engineering school of approximately 2,000 students who alternate between six-week periods of academic study and six weeks of related work experience in…

  5. Women Engineer.

    Science.gov (United States)

    Neustadtl, Sara Jane

    This booklet is designed to provide information to girls about the nature of and possible career opportunities in engineering. Following a brief introduction in which the characteristics of engineers are outlined (such as ability to solve problems, interest in science/mathematics, and urge to make creative use of their intelligence), answers to…

  6. Genetic Engineering

    Science.gov (United States)

    Phillips, John

    1973-01-01

    Presents a review of genetic engineering, in which the genotypes of plants and animals (including human genotypes) may be manipulated for the benefit of the human species. Discusses associated problems and solutions and provides an extensive bibliography of literature relating to genetic engineering. (JR)

  7. Biomedical Engineering

    CERN Document Server

    Suh, Sang C; Tanik, Murat M

    2011-01-01

    Biomedical Engineering: Health Care Systems, Technology and Techniques is an edited volume with contributions from world experts. It provides readers with unique contributions related to current research and future healthcare systems. Practitioners and researchers focused on computer science, bioinformatics, engineering and medicine will find this book a valuable reference.

  8. Systems Engineering

    Science.gov (United States)

    Pellerano, Fernando

    2015-01-01

    This short course provides information on what systems engineering is and how the systems engineer guides requirements, interfaces with the discipline leads, and resolves technical issues. There are many system-wide issues that either impact or are impacted by the thermal subsystem. This course will introduce these issues and illustrate them with real life examples.

  9. Emotional engineering

    CERN Document Server

    In an age of increasing complexity, diversification and change, customers expect services that cater to their needs and to their tastes. Emotional Engineering vol 2. describes how their expectations can be satisfied and managed throughout the product life cycle, if producers focus their attention more on emotion. Emotional engineering provides the means to integrate products to create a new social framework and develops services beyond product realization to create of value across a full lifetime.  14 chapters cover a wide range of topics that can be applied to product, process and industry development, with special attention paid to the increasing importance of sensing in the age of extensive and frequent changes, including: • Multisensory stimulation and user experience  • Physiological measurement • Tactile sensation • Emotional quality management • Mental model • Kansei engineering.   Emotional Engineering vol 2 builds on Dr Fukuda’s previous book, Emotional Engineering, and provides read...

  10. Tratamento cirúrgico das lesões osteocondrais do joelho com mosaicoplastia Surgical treatment of osteochondral lesions of the knee with mosaicplasty

    Directory of Open Access Journals (Sweden)

    Ozório de Almeida Lira Neto

    2010-01-01

    Full Text Available OBJETIVO: Avaliação dos resultados funcionais da técnica de mosaicoplastia em joelhos de pacientes com lesão osteocondral. MÉTODOS: No período de agosto de 1999 a março de 2005, 27 pacientes foram submetidos à mosaicoplastia do joelho. Vinte e um eram do sexo masculino e seis, do feminino. A idade variou de 16 a 64 anos (média de 38,1 anos. Dezessete lesões eram do lado direito e 10, do esquerdo. Em relação à localização da lesão, quatro (15% situaram-se no côndilo femoral lateral, 18 (66,5% no côndilo femoral medial e 5 (18,5% na patela. O tamanho das lesões variou de 1 a 8cm² (média de 2,7cm². Os pacientes operados foram avaliados no pré e pós-operatórios pela escala funcional de Lysholm, com seguimento médio de 2,5 anos. RESULTADOS: O pré-operatório teve uma média de 62,7 pontos e o pós-operatório uma média de 95,4 pontos. Os pacientes submetidos à mosaicoplastia no côndilo femoral lateral apresentaram, no pré-operatório, a média de pontos de 51,5 pontos e, no pós-operatório, média de 100 pontos. No côndilo femoral medial a média no pré-operatório foi de 64,1 pontos e, no pós-operatório, de 95,4 pontos. Com relação à patela, a média do pré-operatório foi de 66,4 pontos e, do pós-operatório, de 92 pontos. CONCLUSÃO: A mosaicoplastia mostrou-se uma boa alternativa no tratamento das lesões osteocondrais do joelho. Entretanto, apresentou melhor evolução nas lesões dos côndilos femorais em relação às localizadas na patela.OBJECTIVE: To evaluate the functional results of mosaicplasty in knees of patients with osteochondral lesion. METHODS: Between August 1999 and March 2005, twenty-seven patients were submitted to mosaicplasty on the knee. Twenty-one were male and six female. The patients' ages ranged from 16 to 64 years (average 38.1 years. Seventeen lesions were located on the right knee and ten on the left one. The lesion was located on the lateral condyle in 4 patients (15%, on the

  11. Channeled Scaffolds for Engineering Myocardium with Mechanical Stimulation

    Science.gov (United States)

    Zhang, Ting; Wan, Leo Q.; Xiong, Zhuo; Marsano, Anna; Maidhof, Robert; Park, Miri; Yan, Yongnian; Vunjak-Novakovic, Gordana

    2011-01-01

    The characteristics of the matrix (composition, structure, mechanical properties) and external culture environment (pulsatile perfusion, physical stimulation) are critically important for engineering functional myocardial tissue. We report the development of chitosan-collagen scaffolds with micro-pores and an array of parallel channels (~200 μm in diameter) that were specifically designed for cardiac tissue engineering with mechanical stimulation. The scaffolds were designed to have the structural and mechanical properties similar to those of the native human heart matrix. Scaffolds were seeded with neonatal rat heart cells and subjected to dynamic tensile stretch using a custom-designed bioreactor. The channels enhanced oxygen transport and facilitated the establishment of cell connections within the construct. The myocardial patches (14 mm in diameter, 1–2 mm thick) consisted of metabolically active cells and started to contract synchronously after 3 days of culture. Mechanical stimulation with high tensile stresses promoted cell alignment, elongation, and the expression of connexin-43 (Cx-43). This study confirms the importance of scaffold design and mechanical stimulation for the formation of contractile cardiac constructs. PMID:22081518

  12. Channelled scaffolds for engineering myocardium with mechanical stimulation.

    Science.gov (United States)

    Zhang, Ting; Wan, Leo Q; Xiong, Zhuo; Marsano, Anna; Maidhof, Robert; Park, Miri; Yan, Yongnian; Vunjak-Novakovic, Gordana

    2012-10-01

    The characteristics of the matrix (composition, structure, mechanical properties) and external culture environment (pulsatile perfusion, physical stimulation) of the heart are important characteristics in the engineering of functional myocardial tissue. This study reports on the development of chitosan-collagen scaffolds with micropores and an array of parallel channels (~ 200 µm in diameter) that were specifically designed for cardiac tissue engineering using mechanical stimulation. The scaffolds were designed to have similar structural and mechanical properties of those of native heart matrix. Scaffolds were seeded with neonatal rat heart cells and subjected to dynamic tensile stretch using a custom designed bioreactor. The channels enhanced oxygen transport and facilitated the establishment of cell connections within the construct. The myocardial patches (14 mm in diameter, 1-2 mm thick) consisted of metabolically active cells that began to contract synchronously after 3 days of culture. Mechanical stimulation with high tensile stress promoted cell alignment, elongation, and expression of connexin-43 (Cx-43). This study confirms the importance of scaffold design and mechanical stimulation for the formation of contractile cardiac constructs. Copyright © 2011 John Wiley & Sons, Ltd.

  13. Glycosylation Engineering

    DEFF Research Database (Denmark)

    Clausen, Henrik; Wandall, Hans H.; Steentoft, Catharina

    2017-01-01

    Knowledge of the cellular pathways of glycosylation across phylogeny provides opportunities for designing glycans via genetic engineering in a wide variety of cell types including bacteria, fungi, plant cells, and mammalian cells. The commercial demand for glycosylation engineering is broad......, including production of biological therapeutics with defined glycosylation (Chapter 57). This chapter describes how knowledge of glycan structures and their metabolism (Parts I–III of this book) has led to the current state of glycosylation engineering in different cell types. Perspectives for rapid...

  14. Engineering mathematics

    CERN Document Server

    Bird, John

    2014-01-01

    A practical introduction to the core mathematics required for engineering study and practiceNow in its seventh edition, Engineering Mathematics is an established textbook that has helped thousands of students to succeed in their exams.John Bird's approach is based on worked examples and interactive problems. This makes it ideal for students from a wide range of academic backgrounds as the student can work through the material at their own pace. Mathematical theories are explained in a straightforward manner, being supported by practical engineering examples and applications in order to ensure

  15. Harmonic engine

    Science.gov (United States)

    Bennett, Charles L [Livermore, CA

    2009-10-20

    A high efficiency harmonic engine based on a resonantly reciprocating piston expander that extracts work from heat and pressurizes working fluid in a reciprocating piston compressor. The engine preferably includes harmonic oscillator valves capable of oscillating at a resonant frequency for controlling the flow of working fluid into and out of the expander, and also preferably includes a shunt line connecting an expansion chamber of the expander to a buffer chamber of the expander for minimizing pressure variations in the fluidic circuit of the engine. The engine is especially designed to operate with very high temperature input to the expander and very low temperature input to the compressor, to produce very high thermal conversion efficiency.

  16. ENGINEERING PSYCHOLOGY,

    Science.gov (United States)

    MAN MACHINE SYSTEMS, APPLIED PSYCHOLOGY ), INFORMATION THEORY, ELECTROPHYSIOLOGY, HUMAN FACTORS ENGINEERING, PERCEPTION( PSYCHOLOGY ...PSYCHOPHYSIOLOGY, AUTOMATION, BRAIN, AUDITORY PERCEPTION, VISUAL PERCEPTION, MEMORY( PSYCHOLOGY ), MOTOR REACTIONS, NOISE, PERFORMANCE(HUMAN), USSR

  17. Green Engineering

    Science.gov (United States)

    Green Engineering is the design, commercialization and use of processes and products that are feasible and economical while reducing the generation of pollution at the source and minimizing the risk to human health and the environment.

  18. Software engineering

    CERN Document Server

    Sommerville, Ian

    2016-01-01

    For courses in computer science and software engineering The Fundamental Practice of Software Engineering Software Engineering introduces readers to the overwhelmingly important subject of software programming and development. In the past few years, computer systems have come to dominate not just our technological growth, but the foundations of our world's major industries. This text seeks to lay out the fundamental concepts of this huge and continually growing subject area in a clear and comprehensive manner. The Tenth Edition contains new information that highlights various technological updates of recent years, providing readers with highly relevant and current information. Sommerville's experience in system dependability and systems engineering guides the text through a traditional plan-based approach that incorporates some novel agile methods. The text strives to teach the innovators of tomorrow how to create software that will make our world a better, safer, and more advanced place to live.

  19. Coastal Engineering

    OpenAIRE

    Van der Velden, E.T.J.M.

    1989-01-01

    Introduction, waves, sediment transport, littoral transport, lonshore sediment transport, onshore-offshore sediment transport, coastal changes, dune erosion and storm surges, sedimentation in channels and trenches, coastal engineering in practice.

  20. Cognitive engineering.

    Science.gov (United States)

    Wilson, Kyle M; Helton, William S; Wiggins, Mark W

    2013-01-01

    Cognitive engineering is the application of cognitive psychology and related disciplines to the design and operation of human-machine systems. Cognitive engineering combines both detailed and close study of the human worker in the actual work context and the study of the worker in more controlled environments. Cognitive engineering combines multiple methods and perspectives to achieve the goal of improved system performance. Given the origins of experimental psychology itself in issues regarding the design of human-machine systems, cognitive engineering is a core, or fundamental, discipline within academic psychology. WIREs Cogn Sci 2013, 4:17-31. doi: 10.1002/wcs.1204 CONFLICT OF INTEREST: The authors declare no conflict of interest. For further resources related to this article, please visit the WIREs website. Copyright © 2012 John Wiley & Sons, Ltd.

  1. Engineering liver

    OpenAIRE

    Linda G Griffith; Wells, Alan; Stolz, Donna Beer

    2013-01-01

    Interest in “engineering liver” arises from multiple communities: therapeutic replacement; mechanistic models of human processes; and drug safety and efficacy studies. An explosion of micro- and nano-fabrication, biomaterials, microfluidic, and other technologies potentially afford unprecedented opportunity to create microphysiological models of human liver, but engineering design principles for how to deploy these tools effectively towards specific applications, including how to define the e...

  2. Microwave engineering

    CERN Document Server

    Pozar, David M

    2012-01-01

    The 4th edition of this classic text provides a thorough coverage of RF and microwave engineering concepts, starting from fundamental principles of electrical engineering, with applications to microwave circuits and devices of practical importance.  Coverage includes microwave network analysis, impedance matching, directional couplers and hybrids, microwave filters, ferrite devices, noise, nonlinear effects, and the design of microwave oscillators, amplifiers, and mixers. Material on microwave and RF systems includes wireless communications, radar, radiometry, and radiation hazards. A large

  3. Geospatial Engineering

    Science.gov (United States)

    2017-02-22

    that enable terrain visualization . Geospatial engineers manipulate the TGD to create the SSGF. The SSGF is the foundation for the Web map service that...decision aids, and visualization products that enable the commander and staff to visualize the operational environment. Geospatial engineers aid in the...data that provides a common framework for visualizing an area of interest (AOI) to enable mission command and the planning and execution of operational

  4. Web Engineering

    OpenAIRE

    Deshpande, Yogesh; Murugesan, San; Ginige, Athula; Hansen, Steve; Schwabe, Daniel; Gaedke, Martin; White, Bebo

    2003-01-01

    Web Engineering is the application of systematic, disciplined and quantifiable approaches to development, operation, and maintenance of Web-based applications. It is both a pro-active approach and a growing collection of theoretical and empirical research in Web application development. This paper gives an overview of Web Engineering by addressing the questions: a) why is it needed? b) what is its domain of operation? c) how does it help and what should it do to improve Web application develo...

  5. Climate engineering

    OpenAIRE

    Platt, Ulrich

    2014-01-01

    Es klingt wie eine Mischung aus Größenwahn und Science Fiction: Wissenschaftler wollen das Klima mit Hightechverfahren beeinflussen. "Climate engineering" heißt der Fachbegriff. Natürlich geht es dabei nicht um den verregneten Sommer, sondern um den globalen Klimawandel. Campus-Reporter Nils Birschmann hat sich bei den Umweltforschern der Uni Heidelberg umgehört, ob was dran ist am "climate engineering". Der Beitrag erschien in der Sendereihe "Campus-Report" - einer Beitragsreihe, in ...

  6. Offshore Engineering

    OpenAIRE

    Vannucci, P

    2008-01-01

    Master; This course on Offshore Engineering is a basic course serving as an introduction to the problems concerning design and construction of offshore platforms, normally used in oil industry. So, some topics will be considered in this course, namely the principal ones that concern the structural design of an offshore platform; some other topics, like for instance marine installation procedures, corrosion protection, facilities and plants engineering will not be considered here. The course i...

  7. Systems Engineering

    OpenAIRE

    Vaughan, William W.

    2016-01-01

    The term “systems engineering” when entered into the Google search page, produces a significant number of results, evidence that systems engineering is recognized as being important for the success of essentially all products. Since most readers of this item will be rather well versed in documents concerning systems engineering, I have elected to share some of the points made on this subject in a document developed by the European Cooperation for Space Standardization (ECSS), a component of t...

  8. Rehabilitation Engineering: What is Rehabilitation Engineering?

    Science.gov (United States)

    ... Parents/Teachers Resource Links for Students Glossary Rehabilitation Engineering What is rehabilitation engineering? How can future rehabilitation ... the area of rehabilitation engineering? What is rehabilitation engineering? Powered prosthetic leg. Source : M. Goldfarb, Vanderbilt U. ...

  9. Fractal engine

    Science.gov (United States)

    Fatemi, Omid; Panchanathan, Sethuraman

    1997-01-01

    Visual media processing is becoming increasingly important because of the wide variety of image and video based applications. Recently, several architectures have been reported in the literature to implement image and video processing algorithms. They range from programmable DSP processors to application specific integrated circuits (ASICs). DSPs have to be software programed to execute individual operations in image and video processing. However they are not suitable for real-time execution of highly compute intensive applications such as fractal block processing (FBP). On the other hand, dedicated architectures and ASICs are designed to implement specific functions. Since they are optimized for a specific task, they cannot be used in a wide variety of applications. In this paper, we propose a parallel and pipelined architecture called fractal engine to implement the operations in FBP. Fractal engine is simple, modular, scaleable and is optimized to execute both low level and mid level operations. We note that implementation of the basic operations by fractal engine enables efficient execution of a majority of visual computing tasks. These include spatial filtering, contrast enhancement, frequency domain operations, histogram calculation, geometric transforms, indexing, vector quantization, fractal block coding, motion estimation, etc. The individual modules of fractal engine have been implemented in VHDL (VHSIC hardware description language). We have chosen to demonstrate the real-time execution capability of fractal engine by mapping a fractal block coding (FBC) algorithm onto the proposed architecture.

  10. Engineering Optics

    CERN Document Server

    Iizuka, Keigo

    2008-01-01

    Engineering Optics is a book for students who want to apply their knowledge of optics to engineering problems, as well as for engineering students who want to acquire the basic principles of optics. It covers such important topics as optical signal processing, holography, tomography, holographic radars, fiber optical communication, electro- and acousto-optic devices, and integrated optics (including optical bistability). As a basis for understanding these topics, the first few chapters give easy-to-follow explanations of diffraction theory, Fourier transforms, and geometrical optics. Practical examples, such as the video disk, the Fresnel zone plate, and many more, appear throughout the text, together with numerous solved exercises. There is an entirely new section in this updated edition on 3-D imaging.

  11. Engineering physics

    CERN Document Server

    Mukherji, Uma

    2015-01-01

    ENGINEERING PHYSICS is designed as a textbook for first year engineering students of a two semester course in Applied Physics according to new revised syllabus. However the scope of this book is not only limited to undergraduate engineering students and science students, it can also serve as a reference book for practicing scientists.Advanced technological topics like LCD, Squid, Maglev system, Electron microscopes, MRI, Photonics - Photonic fibre, Nano-particles, CNT, Quantum computing etc., are explained with basic underlying principles of Physics.This text explained following topics with numerous solved, unsolved problems and questions from different angles. Part-I contains crystal structure, Liquid crystal, Thermo-electric effect, Thermionic emission, Ultrasonic, Acoustics, semiconductor and magnetic materials. Whereas Part-2 contains Optics, X-rays, Electron optics, Dielectric materials, Quantum Physics and Schrodinger wave equation, Laser, Fibre-optics and Holography, Radio-activity, Super-conductivity,...

  12. Engineering surveying

    CERN Document Server

    Schofield, W

    2007-01-01

    Engineering surveying involves determining the position of natural and man-made features on or beneath the Earth's surface and utilizing these features in the planning, design and construction of works. It is a critical part of any engineering project. Without an accurate understanding of the size, shape and nature of the site the project risks expensive and time-consuming errors or even catastrophic failure.Engineering Surveying 6th edition covers all the basic principles and practice of this complex subject and the authors bring expertise and clarity. Previous editions of this classic text have given readers a clear understanding of fundamentals such as vertical control, distance, angles and position right through to the most modern technologies, and this fully updated edition continues that tradition.This sixth edition includes:* An introduction to geodesy to facilitate greater understanding of satellite systems* A fully updated chapter on GPS, GLONASS and GALILEO for satellite positioning in surveying* Al...

  13. Engineering tribology

    CERN Document Server

    Stachowiak, Gwidon

    2014-01-01

    Engineering Tribology, 4th Edition is an established introductory reference focusing on the key concepts and engineering implications of tribology. Taking an interdisciplinary view, the book brings together the relevant knowledge from different fields needed to achieve effective analysis and control of friction and wear. Updated to cover recent advances in tribology, this new edition includes new sections on ionic and mesogenic lubricants, surface texturing, and multiscale characterization of 3D surfaces and coatings. Current trends in nanotribology are discussed, such as those relating to

  14. Micro Engineering

    DEFF Research Database (Denmark)

    Alting, Leo; Kimura, F.; Hansen, Hans Nørgaard

    2003-01-01

    The paper addresses the questions of how micro products are designed and how they are manufactured. Definitions of micro products and micro engineering are discussed and the presentation is aimed at describing typical issues, possibilities and tools regarding design of micro products. The implica......The paper addresses the questions of how micro products are designed and how they are manufactured. Definitions of micro products and micro engineering are discussed and the presentation is aimed at describing typical issues, possibilities and tools regarding design of micro products...

  15. Combustion engineering

    CERN Document Server

    Ragland, Kenneth W

    2011-01-01

    Introduction to Combustion Engineering The Nature of Combustion Combustion Emissions Global Climate Change Sustainability World Energy Production Structure of the Book   Section I: Basic Concepts Fuels Gaseous Fuels Liquid Fuels Solid Fuels Problems Thermodynamics of Combustion Review of First Law Concepts Properties of Mixtures Combustion StoichiometryChemical EnergyChemical EquilibriumAdiabatic Flame TemperatureChemical Kinetics of CombustionElementary ReactionsChain ReactionsGlobal ReactionsNitric Oxide KineticsReactions at a Solid SurfaceProblemsReferences  Section II: Combustion of Gaseous and Vaporized FuelsFlamesLaminar Premixed FlamesLaminar Flame TheoryTurbulent Premixed FlamesExplosion LimitsDiffusion FlamesGas-Fired Furnaces and BoilersEnergy Balance and EfficiencyFuel SubstitutionResidential Gas BurnersIndustrial Gas BurnersUtility Gas BurnersLow Swirl Gas BurnersPremixed-Charge Engine CombustionIntroduction to the Spark Ignition EngineEngine EfficiencyOne-Zone Model of Combustion in a Piston-...

  16. Metabolic Engineering

    Indian Academy of Sciences (India)

    IAS Admin

    processes such as generation of energy, production of fundamen- tal building blocks required for structural organization and syn- thesis of biomolecules having specialized functions. ... Symbiosis International. University, Pune. His research interests are in metabolic engineering of lactic acid bacteria for increasing their.

  17. Harmonic engine

    Science.gov (United States)

    Bennett, Charles L.; Sewall, Noel; Boroa, Carl

    2014-08-19

    An engine based on a reciprocating piston engine that extracts work from pressurized working fluid. The engine includes a harmonic oscillator inlet valve capable of oscillating at a resonant frequency for controlling the flow of working fluid into of the engine. In particular, the inlet valve includes an inlet valve head and a spring arranged together as a harmonic oscillator so that the inlet valve head is moveable from an unbiased equilibrium position to a biased closed position occluding an inlet. Upon releasing the inlet valve the inlet valve head undergoes a single oscillation past the equilibrium positio to a maximum open position and returns to a biased return position close to the closed position to choke the flow and produce a pressure drop across the inlet valve causing the inlet valve to close. Protrusions carried either by the inlet valve head or piston head are used to bump open the inlet valve from the closed position and initiate the single oscillation of the inlet valve head, and protrusions carried either by the outlet valve head or piston head are used to close the outlet valve ahead of the bump opening of the inlet valve.

  18. Exhibit Engineering

    DEFF Research Database (Denmark)

    Mortensen, Marianne Foss

    ) a synthesis of the findings from the first two studies with findings from the literature to generate two types of results: a coherent series of suggestions for a design iteration of the studied exhibit as well as a more general normative model for exhibit engineering. Finally, another perspective...

  19. Enhancing Engineering Education through Engineering Management

    Science.gov (United States)

    Pence, Kenneth R.; Rowe, Christopher J.

    2012-01-01

    Engineering Management courses are added to a traditional engineering curriculum to enhance the value of an undergraduate's engineering degree. A four-year engineering degree often leaves graduates lacking in business and management acumen. Engineering management education covers topics enhancing the value of new graduates by teaching management…

  20. O uso da matriz óssea desmineralizada na reparação de lesões osteocondrais: estudo experimental em coelhos The use of demineralized bone matrix in the repair of osteochondral lesions: experimental study in rabbits

    Directory of Open Access Journals (Sweden)

    Aldo José Fernando da Costa

    2001-12-01

    the use of the demineralized bone matrix in the repair of osteochondral lesions. The articular cartilage has little regeneration capacity because of its histological features and the absence of blood vessels. Implants of tissues and culture of chondrogenic cells have been used for the treatment of osteochondral lesions, but show technical difficulties of fixation and mechanical support of the subchondral region. The demineralized bone matrix can technically facilitate the fixation of these implants because it is a firm material with elastic features. Besides having osteogenic capacity and producing subchondral bone tissue and then working as mechanical support, it also has inductor factors of chondrogenesis. Osteochondral lesions were produced in the knees of 15 rabbits and the left knees were treated with the demineralized bone matrix, and the right knees were used like control of the study. Macroscopic and histological evaluations were made with 02, 04 and 06 weeks. In the lesions treated with the demineralized bone matrix it was obtained 100% of viability of the graft and the formation of a plain regular repair tissue which filled the lesion completely with DBM. The histological analysis revealed bone neoformation and integration of the graft with the bone tissue in the subchondral region, and in superficial region of the lesion occurred the induction of the formation of chondrogenic tissue. The conclusion of this study is that the demineralized bone matrix is useful in the repair of osteochondral lesions because of its capacity of bone induction, integration to the subchondral bone tissue and induction of the formation of chondrogenic tissue. It can be used as a component of a composite graft with chondrogenic tissue or culture of chondrogenic cells for the treatment of osteochondral lesions, and can decrease the technical difficulties of fixation and support of these implants.

  1. Engineering Review Information System

    Science.gov (United States)

    Grems, III, Edward G. (Inventor); Henze, James E. (Inventor); Bixby, Jonathan A. (Inventor); Roberts, Mark (Inventor); Mann, Thomas (Inventor)

    2015-01-01

    A disciplinal engineering review computer information system and method by defining a database of disciplinal engineering review process entities for an enterprise engineering program, opening a computer supported engineering item based upon the defined disciplinal engineering review process entities, managing a review of the opened engineering item according to the defined disciplinal engineering review process entities, and closing the opened engineering item according to the opened engineering item review.

  2. Engineering Tribology

    Science.gov (United States)

    Williams, John

    An ideal textbook for a first tribology course, this book provides an interdisciplinary understanding of the field. It includes materials constraints, real design problems and solutions (such as those for journal and rolling element bearing), cams and followers and heavily loaded gear teeth. Including physics, materials science, and surface and lubricant chemistry, the volume integrates quantitative material from a wide variety of disciplines with traditional engineering approaches.

  3. Planetary engineering

    Science.gov (United States)

    Pollack, James B.; Sagan, Carl

    Assuming commercial fusion power, heavy lift vehicles and major advances in genetic engineering, the authors survey possible late-21st century methods of working major transformations in planetary environments. Much more Earthlike climates may be produced on Mars by generating low freezing point greenhouse gases from indigenous materials; on Venus by biological conversion of CO2 to graphite, by canceling the greenhouse effect with high-altitude absorbing fine particles, or by a sunshield at the first Lagrangian point; and on Titan by greenhouses and/or fusion warming. However, in our present state of ignorance we cannot guarantee a stable endstate or exclude unanticipated climatic feedbacks or other unintended consequences. Moreover, as the authors illustrate by several examples, many conceivable modes of planetary engineering are so wasteful of scarce solar system resources and so destructive of important scientific information as to raise profound ethical issues, even if they were economically feasible, which they are not. Global warming on Earth may lead to calls for mitigation by planetary engineering, e.g., emplacement and replenishment of anti-greenhouse layers at high altitudes, or sunshields in space. But here especially we must be concerned about precision, stability, and inadvertent side-effects. The safest and most cost-effective means of countering global warming - beyond, e.g., improved energy efficiency, CFC bans and alternative energy sources - is the continuing reforestation of approximately 2 times 107 sq km of the Earth's surface. This can be accomplished with present technology and probably at the least cost.

  4. Web Engineering

    Energy Technology Data Exchange (ETDEWEB)

    White, Bebo

    2003-06-23

    Web Engineering is the application of systematic, disciplined and quantifiable approaches to development, operation, and maintenance of Web-based applications. It is both a pro-active approach and a growing collection of theoretical and empirical research in Web application development. This paper gives an overview of Web Engineering by addressing the questions: (a) why is it needed? (b) what is its domain of operation? (c) how does it help and what should it do to improve Web application development? and (d) how should it be incorporated in education and training? The paper discusses the significant differences that exist between Web applications and conventional software, the taxonomy of Web applications, the progress made so far and the research issues and experience of creating a specialization at the master's level. The paper reaches a conclusion that Web Engineering at this stage is a moving target since Web technologies are constantly evolving, making new types of applications possible, which in turn may require innovations in how they are built, deployed and maintained.

  5. Inorganic-organic hydrogel scaffolds for tissue engineering

    Science.gov (United States)

    Bailey, Brennan Margaret

    Analogous to the extracellular matrix (ECM) of natural tissues, properties of a tissue engineering scaffold direct cell behavior and thus regenerated tissue properties. These include both physical properties (e.g. morphology and modulus) and chemical properties (e.g. hydrophobicity, hydration and bioactivity). Notably, recent studies suggest that scaffold properties (e.g. modulus) may be as potent as growth factors in terms of directing stem cell fate. Thus, 3D scaffolds possessing specific properties modified for optimal cell regeneration have the potential to regenerate native-like tissues. Photopolymerizable poly(ethylene glycol) diacrylate (PEG-DA)-based hydrogels are frequently used as scaffolds for tissue engineering. They are ideal for controlled studies of cell-material interactions due to their poor protein adsorption in the absence of adhesive ligands thereby making them "biological blank slates". However, their range of physical and chemical properties is limited. Thus, hydrogel scaffolds which maintain the benefits of PEG-DA but possess a broader set of tunable properties would allow the establishment of predictive relationships between scaffold properties, cell behavior and regenerated tissue properties. Towards this goal, this work describes a series of unique hybrid inorganic-organic hydrogel scaffolds prepared using different solvents and also in the form of continuous gradients. Properties relevant to tissue regeneration were investigated including: swelling, morphology, modulus, degradation rates, bioactivity, cytocompatibility, and protein adhesion. These scaffolds were based on the incorporation of hydrophobic, bioactive and osteoinductive methacrylated star polydimethylsiloxane (PDMSstar-MA) ["inorganic component"] into hydrophilic PEG-DA ["organic component"]. The following parameters were varied: molecular weight (Mn) of PEG-DA (Mn = 3k & 6k g/mol) and PDMSstar-MA (Mn = 1.8k, 7k, 14k), ratio of PDMSstar-MA to PEG-DA (0:100 to 20:80), total

  6. Engineering justice transforming engineering education and practice

    CERN Document Server

    Leydens, Jon A

    2018-01-01

    Using social justice as a catalyst for curricular transformation, Engineering Justice presents an examination of how politics, culture, and other social issues are inherent in the practice of engineering. It aims to align engineering curricula with socially just outcomes, increase enrollment among underrepresented groups, and lessen lingering gender, class, and ethnicity gaps by showing how the power of engineering knowledge can be explicitly harnessed to serve the underserved and address social inequalities. This book is meant to transform the way educators think about engineering curricula through creating or transforming existing courses to attract, retain, and motivate engineering students to become professionals who enact engineering for social justice. Engineering Justice offers thought-provoking chapters on: why social justice is inherent yet often invisible in engineering education and practice; engineering design for social justice; social justice in the engineering sciences; social justice in human...

  7. Protein Corona Influences Cell-Biomaterial Interactions in Nanostructured Tissue Engineering Scaffolds.

    Science.gov (United States)

    Serpooshan, Vahid; Mahmoudi, Morteza; Zhao, Mingming; Wei, Ke; Sivanesan, Senthilkumar; Motamedchaboki, Khatereh; Malkovskiy, Andrey V; Gladstone, Andrew B; Cohen, Jeffrey E; Yang, Phillip C; Rajadas, Jayakumar; Bernstein, Daniel; Woo, Y Joseph; Ruiz-Lozano, Pilar

    2015-07-22

    Biomaterials are extensively used to restore damaged tissues, in the forms of implants (e.g. tissue engineered scaffolds) or biomedical devices (e.g. pacemakers). Once in contact with the physiological environment, nanostructured biomaterials undergo modifications as a result of endogenous proteins binding to their surface. The formation of this macromolecular coating complex, known as 'protein corona', onto the surface of nanoparticles and its effect on cell-particle interactions are currently under intense investigation. In striking contrast, protein corona constructs within nanostructured porous tissue engineering scaffolds remain poorly characterized. As organismal systems are highly dynamic, it is conceivable that the formation of distinct protein corona on implanted scaffolds might itself modulate cell-extracellular matrix interactions. Here, we report that corona complexes formed onto the fibrils of engineered collagen scaffolds display specific, distinct, and reproducible compositions that are a signature of the tissue microenvironment as well as being indicative of the subject's health condition. Protein corona formed on collagen matrices modulated cellular secretome in a context-specific manner ex-vivo , demonstrating their role in regulating scaffold-cellular interactions. Together, these findings underscore the importance of custom-designing personalized nanostructured biomaterials, according to the biological milieu and disease state. We propose the use of protein corona as in situ biosensor of temporal and local biomarkers.

  8. Protein Corona Influences Cell–Biomaterial Interactions in Nanostructured Tissue Engineering Scaffolds

    Science.gov (United States)

    Zhao, Mingming; Wei, Ke; Sivanesan, Senthilkumar; Motamedchaboki, Khatereh; Malkovskiy, Andrey V.; Gladstone, Andrew B.; Cohen, Jeffrey E.; Yang, Phillip C.; Rajadas, Jayakumar; Bernstein, Daniel; Woo, Y. Joseph; Ruiz-Lozano, Pilar

    2016-01-01

    Biomaterials are extensively used to restore damaged tissues, in the forms of implants (e.g. tissue engineered scaffolds) or biomedical devices (e.g. pacemakers). Once in contact with the physiological environment, nanostructured biomaterials undergo modifications as a result of endogenous proteins binding to their surface. The formation of this macromolecular coating complex, known as ‘protein corona’, onto the surface of nanoparticles and its effect on cell-particle interactions are currently under intense investigation. In striking contrast, protein corona constructs within nanostructured porous tissue engineering scaffolds remain poorly characterized. As organismal systems are highly dynamic, it is conceivable that the formation of distinct protein corona on implanted scaffolds might itself modulate cell-extracellular matrix interactions. Here, we report that corona complexes formed onto the fibrils of engineered collagen scaffolds display specific, distinct, and reproducible compositions that are a signature of the tissue microenvironment as well as being indicative of the subject's health condition. Protein corona formed on collagen matrices modulated cellular secretome in a context-specific manner ex-vivo, demonstrating their role in regulating scaffold-cellular interactions. Together, these findings underscore the importance of custom-designing personalized nanostructured biomaterials, according to the biological milieu and disease state. We propose the use of protein corona as in situ biosensor of temporal and local biomarkers. PMID:27516731

  9. Internet Search Engines

    OpenAIRE

    Fatmaa El Zahraa Mohamed Abdou

    2004-01-01

    A general study about the internet search engines, the study deals main 7 points; the differance between search engines and search directories, components of search engines, the percentage of sites covered by search engines, cataloging of sites, the needed time for sites appearance in search engines, search capabilities, and types of search engines.

  10. Microprocessor engineering

    CERN Document Server

    Holdsworth, B

    2013-01-01

    Microprocessor Engineering provides an insight in the structures and operating techniques of a small computer. The book is comprised of 10 chapters that deal with the various aspects of computing. The first two chapters tackle the basic arithmetic and logic processes. The third chapter covers the various memory devices, both ROM and RWM. Next, the book deals with the general architecture of microprocessor. The succeeding three chapters discuss the software aspects of machine operation, while the last remaining three chapters talk about the relationship of the microprocessor with the outside wo

  11. Engineering Encounters: Teaching Educators about Engineering

    Science.gov (United States)

    Tank, Kristina M.; Raman, D. Raj; Lamm, Monica H.; Sundararajan, Sriram; Estapa, Anne

    2017-01-01

    This column presents ideas and techniques to enhance science teaching. This month's issue describes preservice elementary teachers learning engineering principles from engineers. Few elementary teachers have experience with implementing engineering into the classroom. While engineering professional development opportunities for inservice teachers…

  12. Nano surface engineering and remanufacture engineering

    Institute of Scientific and Technical Information of China (English)

    XU Bin-shi

    2004-01-01

    Nano surface engineering and remanufacture engineering are introduced, and the relationship between them is set forth. It points out the superiority of nano surface engineering to the traditional one, and reveals the advantages of remanufacture engineering. Taking some nano surface techniques as samples, such as nano-materials brush electroplating, nano-materials thermal spraying and nano-materials self-repairing antifriction additive technology, it shows the applications of nano surface engineering technology to remanufacturing mechanical parts.

  13. Engineering electromagnetics

    CERN Document Server

    Thomas, David T; Hartnett, James P; Hughes, William F

    1973-01-01

    The applications involving electromagnetic fields are so pervasive that it is difficult to estimate their contribution to the industrial output: generation of electricity, power transmission lines, electric motors, actuators, relays, radio, TV and microwave transmission and reception, magnetic storage, and even the mundane little magnet used to hold a paper note on the refrigerator are all electromagnetic in nature. One would be hard pressed to find a device that works without relaying on any electromagnetic principle or effect. This text provides a good theoretical understanding of the electromagnetic field equations but also treats a large number of applications. In fact, no topic is presented unless it is directly applicable to engineering design or unless it is needed for the understanding of another topic. In electrostatics, for example, the text includes discussions of photocopying, ink-jet printing, electrostatic separation and deposition, sandpaper production, paint spraying, and powder coating. In ma...

  14. Engineering viscoelasticity

    CERN Document Server

    Gutierrez-Lemini, Danton

    2014-01-01

    Engineering Viscoelasticity covers all aspects of the thermo- mechanical response of viscoelastic substances that a practitioner in the field of viscoelasticity would need to design experiments, interpret test data, develop stress-strain models, perform stress analyses, design structural components, and carry out research work. The material in each chapter is developed from the elementary to the advanced, providing the background in mathematics and mechanics that are central to understanding the subject matter being presented. The book examines how viscoelastic materials respond to the application of loads, and provides practical guidelines to use them in the design of commercial, military and industrial applications. This book also: ·         Facilitates conceptual understanding by progressing in each chapter from elementary to challenging material ·         Examines in detail both differential and integral constitutive equations, devoting full chapters to each type and using both forms in ...

  15. Regenerative engineering

    CERN Document Server

    Laurencin, Cato T

    2013-01-01

    Regenerative Engineering: The Future of Medicine Saadiq F. El-Amin III , MD , PhD; Joylene W.L. Thomas, MD ; Ugonna N. Ihekweazu, MD ; Mia D. Woods, MS; and Ashim Gupta, MSCell Biology Gloria Gronowicz, PhD and Karen Sagomonyants, DMDStem Cells and Tissue Regeneration Kristen Martins-Taylor, PhD; Xiaofang Wang, MD , PhD; Xue-Jun Li, PhD; and Ren-He Xu, MD , PhDIntroduction to Materials Science Sangamesh G. Kumbar, PhD and Cato T. Laurencin, MD , PhDBiomaterials A. Jon Goldberg, PhD and Liisa T. Kuhn, PhDIn Vitro Assessment of Cell-Biomaterial Interactions Yong Wang, PhDHost Response to Biomate

  16. Engineered cartilaginous tubes for tracheal tissue replacement via self-assembly and fusion of human mesenchymal stem cell constructs.

    Science.gov (United States)

    Dikina, Anna D; Strobel, Hannah A; Lai, Bradley P; Rolle, Marsha W; Alsberg, Eben

    2015-06-01

    There is a critical need to engineer a neotrachea because currently there are no long-term treatments for tracheal stenoses affecting large portions of the airway. In this work, a modular tracheal tissue replacement strategy was developed. High-cell density, scaffold-free human mesenchymal stem cell-derived cartilaginous rings and tubes were successfully generated through employment of custom designed culture wells and a ring-to-tube assembly system. Furthermore, incorporation of transforming growth factor-β1-delivering gelatin microspheres into the engineered tissues enhanced chondrogenesis with regard to tissue size and matrix production and distribution in the ring- and tube-shaped constructs, as well as luminal rigidity of the tubes. Importantly, all engineered tissues had similar or improved biomechanical properties compared to rat tracheas, which suggests they could be transplanted into a small animal model for airway defects. The modular, bottom up approach used to grow stem cell-based cartilaginous tubes in this report is a promising platform to engineer complex organs (e.g., trachea), with control over tissue size and geometry, and has the potential to be used to generate autologous tissue implants for human clinical applications. Copyright © 2015 Elsevier Ltd. All rights reserved.

  17. Application of Extrusion-Based Hydrogel Bioprinting for Cartilage Tissue Engineering

    Science.gov (United States)

    You, Fu; Eames, B. Frank; Chen, Xiongbiao

    2017-01-01

    Extrusion-based bioprinting (EBB) is a rapidly developing technique that has made substantial progress in the fabrication of constructs for cartilage tissue engineering (CTE) over the past decade. With this technique, cell-laden hydrogels or bio-inks have been extruded onto printing stages, layer-by-layer, to form three-dimensional (3D) constructs with varying sizes, shapes, and resolutions. This paper reviews the cell sources and hydrogels that can be used for bio-ink formulations in CTE application. Additionally, this paper discusses the important properties of bio-inks to be applied in the EBB technique, including biocompatibility, printability, as well as mechanical properties. The printability of a bio-ink is associated with the formation of first layer, ink rheological properties, and crosslinking mechanisms. Further, this paper discusses two bioprinting approaches to build up cartilage constructs, i.e., self-supporting hydrogel bioprinting and hybrid bioprinting, along with their applications in fabricating chondral, osteochondral, and zonally organized cartilage regenerative constructs. Lastly, current limitations and future opportunities of EBB in printing cartilage regenerative constructs are reviewed. PMID:28737701

  18. Application of Extrusion-Based Hydrogel Bioprinting for Cartilage Tissue Engineering.

    Science.gov (United States)

    You, Fu; Eames, B Frank; Chen, Xiongbiao

    2017-07-23

    Extrusion-based bioprinting (EBB) is a rapidly developing technique that has made substantial progress in the fabrication of constructs for cartilage tissue engineering (CTE) over the past decade. With this technique, cell-laden hydrogels or bio-inks have been extruded onto printing stages, layer-by-layer, to form three-dimensional (3D) constructs with varying sizes, shapes, and resolutions. This paper reviews the cell sources and hydrogels that can be used for bio-ink formulations in CTE application. Additionally, this paper discusses the important properties of bio-inks to be applied in the EBB technique, including biocompatibility, printability, as well as mechanical properties. The printability of a bio-ink is associated with the formation of first layer, ink rheological properties, and crosslinking mechanisms. Further, this paper discusses two bioprinting approaches to build up cartilage constructs, i.e., self-supporting hydrogel bioprinting and hybrid bioprinting, along with their applications in fabricating chondral, osteochondral, and zonally organized cartilage regenerative constructs. Lastly, current limitations and future opportunities of EBB in printing cartilage regenerative constructs are reviewed.

  19. Application of Extrusion-Based Hydrogel Bioprinting for Cartilage Tissue Engineering

    Directory of Open Access Journals (Sweden)

    Fu You

    2017-07-01

    Full Text Available Extrusion-based bioprinting (EBB is a rapidly developing technique that has made substantial progress in the fabrication of constructs for cartilage tissue engineering (CTE over the past decade. With this technique, cell-laden hydrogels or bio-inks have been extruded onto printing stages, layer-by-layer, to form three-dimensional (3D constructs with varying sizes, shapes, and resolutions. This paper reviews the cell sources and hydrogels that can be used for bio-ink formulations in CTE application. Additionally, this paper discusses the important properties of bio-inks to be applied in the EBB technique, including biocompatibility, printability, as well as mechanical properties. The printability of a bio-ink is associated with the formation of first layer, ink rheological properties, and crosslinking mechanisms. Further, this paper discusses two bioprinting approaches to build up cartilage constructs, i.e., self-supporting hydrogel bioprinting and hybrid bioprinting, along with their applications in fabricating chondral, osteochondral, and zonally organized cartilage regenerative constructs. Lastly, current limitations and future opportunities of EBB in printing cartilage regenerative constructs are reviewed.

  20. Current concepts: tissue engineering and regenerative medicine applications in the ankle joint.

    Science.gov (United States)

    Correia, S I; Pereira, H; Silva-Correia, J; Van Dijk, C N; Espregueira-Mendes, J; Oliveira, J M; Reis, R L

    2014-03-06

    Tissue engineering and regenerative medicine (TERM) has caused a revolution in present and future trends of medicine and surgery. In different tissues, advanced TERM approaches bring new therapeutic possibilities in general population as well as in young patients and high-level athletes, improving restoration of biological functions and rehabilitation. The mainstream components required to obtain a functional regeneration of tissues may include biodegradable scaffolds, drugs or growth factors and different cell types (either autologous or heterologous) that can be cultured in bioreactor systems (in vitro) prior to implantation into the patient. Particularly in the ankle, which is subject to many different injuries (e.g. acute, chronic, traumatic and degenerative), there is still no definitive and feasible answer to 'conventional' methods. This review aims to provide current concepts of TERM applications to ankle injuries under preclinical and/or clinical research applied to skin, tendon, bone and cartilage problems. A particular attention has been given to biomaterial design and scaffold processing with potential use in osteochondral ankle lesions.

  1. Thermogel-Coated Poly(ε-Caprolactone Composite Scaffold for Enhanced Cartilage Tissue Engineering

    Directory of Open Access Journals (Sweden)

    Shao-Jie Wang

    2016-05-01

    Full Text Available A three-dimensional (3D composite scaffold was prepared for enhanced cartilage tissue engineering, which was composed of a poly(ε-caprolactone (PCL backbone network and a poly(lactide-co-glycolide-block-poly(ethylene glycol-block-poly(lactide-co-glycolide (PLGA–PEG–PLGA thermogel surface. The composite scaffold not only possessed adequate mechanical strength similar to native osteochondral tissue as a benefit of the PCL backbone, but also maintained cell-friendly microenvironment of the hydrogel. The PCL network with homogeneously-controlled pore size and total pore interconnectivity was fabricated by fused deposition modeling (FDM, and was impregnated into the PLGA–PEG–PLGA solution at low temperature (e.g., 4 °C. The PCL/Gel composite scaffold was obtained after gelation induced by incubation at body temperature (i.e., 37 °C. The composite scaffold showed a greater number of cell retention and proliferation in comparison to the PCL platform. In addition, the composite scaffold promoted the encapsulated mesenchymal stromal cells (MSCs to differentiate chondrogenically with a greater amount of cartilage-specific matrix production compared to the PCL scaffold or thermogel. Therefore, the 3D PCL/Gel composite scaffold may exhibit great potential for in vivo cartilage regeneration.

  2. The responsibilities of engineers.

    Science.gov (United States)

    Smith, Justin; Gardoni, Paolo; Murphy, Colleen

    2014-06-01

    Knowledge of the responsibilities of engineers is the foundation for answering ethical questions about the work of engineers. This paper defines the responsibilities of engineers by considering what constitutes the nature of engineering as a particular form of activity. Specifically, this paper focuses on the ethical responsibilities of engineers qua engineers. Such responsibilities refer to the duties acquired in virtue of being a member of a group. We examine the practice of engineering, drawing on the idea of practices developed by philosopher Alasdair MacIntyre, and show how the idea of a practice is important for identifying and justifying the responsibilities of engineers. To demonstrate the contribution that knowledge of the responsibilities of engineers makes to engineering ethics, a case study from structural engineering is discussed. The discussion of the failure of the Sleipner A Platform off the coast of Norway in 1991 demonstrates how the responsibilities of engineers can be derived from knowledge of the nature of engineering and its context.

  3. Engineers and Bildung

    DEFF Research Database (Denmark)

    Henriksen, Lars Bo

    2006-01-01

    What is an engineer? Or maybe better: how are engineers, and how are they “gebilded” in order to be able to be called engineers? In order to shed some light on this question we could ask: How is the relation between engineering and the making of an engineer, or the relation between engineering...... and Bildung. In this chapter, this relation in investigated. In the first part, I present three engineers and their careers. In the second part, the concept of Bildung is analyzed, and in the third part, it is the conceptual relation between Bildung, engineers, and engineering work that is of concern....

  4. Fostering Creative Engineers

    DEFF Research Database (Denmark)

    Zhou, Chunfang

    2012-01-01

    . As the literature demonstrates, this paper reveals the understanding of complexity in engineering practice and the roles of creativity in engineering practice. In addition, the barriers to creativity in current engineering education and some implications of pedagogic strategies will be discussed. So this paper...... that engineering students should master. This paper aims to illustrate deeply why engineering education needs to foster creative students to face the challenges of complex engineering work. So a literature review will be provided by focusing on the necessity of developing creativity in engineering education...... contributes to rethinking the engineering profession in a social context and a link between creativity research and engineering education....

  5. Repair of Osteochondral Defects Using Human Umbilical Cord Wharton’s Jelly-Derived Mesenchymal Stem Cells in a Rabbit Model

    Directory of Open Access Journals (Sweden)

    Shuyun Liu

    2017-01-01

    Full Text Available Umbilical cord Wharton’s jelly-derived mesenchymal stem cell (WJMSC is a new-found mesenchymal stem cell in recent years with multiple lineage potential. Due to its abundant resources, no damage procurement, and lower immunogenicity than other adult MSCs, WJMSC promises to be a good xenogenous cell candidate for tissue engineering. This in vivo pilot study explored the use of human umbilical cord Wharton’s jelly mesenchymal stem cells (hWJMSCs containing a tissue engineering construct xenotransplant in rabbits to repair full-thickness cartilage defects in the femoral patellar groove. We observed orderly spatial-temporal remodeling of hWJMSCs into cartilage tissues during repair over 16 months, with characteristic architectural features, including a hyaline-like neocartilage layer with good surface regularity, complete integration with adjacent host cartilage, and regenerated subchondral bone. No immune rejection was detected when xenograft hWJMSCs were implanted into rabbit cartilage defects. The repair results using hWJMSCs were superior to those of chondrogenically induced hWJMSCs after assessing gross appearance and histological grading scores. These preliminary results suggest that using novel undifferentiated hWJMSCs as seed cells might be a better approach than using transforming growth factor-β-induced differentiated hWJMSCs for in vivo tissue engineering treatment of cartilage defects. hWJMSC allografts may be promising for clinical applications.

  6. Women in Engineering Revisited.

    Science.gov (United States)

    McAfee, Naomi J.

    Engineering as a profession for women is examined. Although 1.0% of the engineering population is presently female, undergraduate enrollment has been increasing steadily since 1970. Some universities today have women representing 10-15% of their engineering enrollment. Beginning salaries are higher for female engineers than for male engineers, but…

  7. Metabolic Engineering X Conference

    Energy Technology Data Exchange (ETDEWEB)

    Flach, Evan [American Institute of Chemical Engineers

    2015-05-07

    The International Metabolic Engineering Society (IMES) and the Society for Biological Engineering (SBE), both technological communities of the American Institute of Chemical Engineers (AIChE), hosted the Metabolic Engineering X Conference (ME-X) on June 15-19, 2014 at the Westin Bayshore in Vancouver, British Columbia. It attracted 395 metabolic engineers from academia, industry and government from around the globe.

  8. Biosystems Engineering in Portugal

    OpenAIRE

    Marques da Silva, José Rafael; Silva, Luis Leopoldo; Cruz,Vasco Fitas

    2008-01-01

    The paper gives the definition of Biosystems Engineering in Portugal; Possible revisions of the core curriculum presented in the FEANI report; the current situation of Biosystems Engineering in Portugal; The impacts of the transition to Biosystems Engineering; The need for a transition to Biosystems Engineering;Opportunities to the Biosystems Engineer in the labour market.

  9. Meta Search Engines.

    Science.gov (United States)

    Garman, Nancy

    1999-01-01

    Describes common options and features to consider in evaluating which meta search engine will best meet a searcher's needs. Discusses number and names of engines searched; other sources and specialty engines; search queries; other search options; and results options. (AEF)

  10. Mold-shaped, nanofiber scaffold-based cartilage engineering using human mesenchymal stem cells and bioreactor.

    Science.gov (United States)

    Janjanin, Sasa; Li, Wan-Ju; Morgan, Meredith T; Shanti, Rabie M; Tuan, Rocky S

    2008-09-01

    Mesenchymal stem cell (MSC)-based tissue engineering is a promising future alternative to autologous cartilage grafting. This study evaluates the potential of using MSCs, seeded into electrospun, biodegradable polymeric nanofibrous scaffolds, to engineer cartilage with defined dimensions and shape, similar to grafts used for subcutaneous implantation in plastic and reconstructive surgery. Human bone marrow derived MSCs seeded onto nanofibrous scaffolds and placed in custom-designed molds were cultured for up to 42 days in bioreactors. Chondrogenesis was induced with either transforming growth factor-beta1 (TGF-beta1) alone or in combination with insulin-like growth factor-I (IGF-I). Constructs exhibited hyaline cartilage histology with desired thickness and shape as well as favorable tissue integrity and shape retention, suggesting the presence of elastic tissue. Time-dependent increase in cartilage matrix gene expression was seen in both types of culture: at Day 42, TGF-beta1/IGF-I treated cultures showed higher collagen Type 2 and aggrecan expression. Both culture conditions showed significant time-dependent increase in sulfated glycosaminoglycan and hydroxyproline contents. TGF-beta1/IGF-I-treated samples were significantly stiffer; with equilibrium compressive Young's modulus values reaching 17 kPa by Day 42. The successful ex vivo development of geometrically defined cartilaginous construct using customized molding suggests the potential of cell-based cartilage tissue for reconstructive surgery.

  11. Tip-Clearance Measurement in the First Stage of the Compressor of an Aircraft Engine

    Directory of Open Access Journals (Sweden)

    Iker García

    2016-11-01

    Full Text Available In this article, we report the design of a reflective intensity-modulated optical fiber sensor for blade tip-clearance measurement, and the experimental results for the first stage of a compressor of an aircraft engine operating in real conditions. The tests were performed in a ground test cell, where the engine completed four cycles from idling state to takeoff and back to idling state. During these tests, the rotational speed of the compressor ranged between 7000 and 15,600 rpm. The main component of the sensor is a tetrafurcated bundle of optical fibers, with which the resulting precision of the experimental measurements was 12 µm for a measurement range from 2 to 4 mm. To get this precision the effect of temperature on the optoelectronic components of the sensor was compensated by calibrating the sensor in a climate chamber. A custom-designed MATLAB program was employed to simulate the behavior of the sensor prior to its manufacture.

  12. Modular Engineering Concept at Novo Nordisk Engineering

    DEFF Research Database (Denmark)

    Moelgaard, Gert; Miller, Thomas Dedenroth

    1997-01-01

    This report describes the concept of a new engineering method at Novo Nordisk Engineering: Modular Engineering (ME). Three tools are designed to support project phases with different levels of detailing and abstraction. ME supports a standard, cross-functional breakdown of projects that facilitates...

  13. Contemporary engineering economics

    CERN Document Server

    Park, Chan S

    2011-01-01

    Contemporary Engineering Economics, 5/e, is intended for undergraduate engineering students taking introductory engineering economics while appealing to the full range of engineering disciplines for which this course is often required: industrial, civil, mechanical, electrical, computer, aerospace, chemical, and manufacturing engineering, as well as engineering technology. This edition has been thoroughly revised and updated while continuing to adopt a contemporary approach to the subject, and teaching, of engineering economics. This text aims not only to build a sound and comprehensive coverage of engineering economics, but also to address key educational challenges, such as student difficulty in developing the analytical skills required to make informed financial decisions.

  14. Engine Test Facility (ETF)

    Data.gov (United States)

    Federal Laboratory Consortium — The Air Force Arnold Engineering Development Center's Engine Test Facility (ETF) test cells are used for development and evaluation testing of propulsion systems for...

  15. Advanced Metasearch Engine Technology

    CERN Document Server

    Meng, Weiyi

    2010-01-01

    Among the search tools currently on the Web, search engines are the most well known thanks to the popularity of major search engines such as Google and Yahoo!. While extremely successful, these major search engines do have serious limitations. This book introduces large-scale metasearch engine technology, which has the potential to overcome the limitations of the major search engines. Essentially, a metasearch engine is a search system that supports unified access to multiple existing search engines by passing the queries it receives to its component search engines and aggregating the returned

  16. Using Collaborative Engineering to Inform Collaboration Engineering

    Science.gov (United States)

    Cooper, Lynne P.

    2012-01-01

    Collaboration is a critical competency for modern organizations as they struggle to compete in an increasingly complex, global environment. A large body of research on collaboration in the workplace focuses both on teams, investigating how groups use teamwork to perform their task work, and on the use of information systems to support team processes ("collaboration engineering"). This research essay presents collaboration from an engineering perspective ("collaborative engineering"). It uses examples from professional and student engineering teams to illustrate key differences in collaborative versus collaboration engineering and investigates how challenges in the former can inform opportunities for the latter.

  17. Bioengineering of plant (tri)terpenoids: from metabolic engineering of plants to synthetic biology in vivo and in vitro.

    Science.gov (United States)

    Moses, Tessa; Pollier, Jacob; Thevelein, Johan M; Goossens, Alain

    2013-10-01

    Terpenoids constitute a large and diverse class of natural products that serve many functions in nature. Most of the tens of thousands of the discovered terpenoids are synthesized by plants, where they function as primary metabolites involved in growth and development, or as secondary metabolites that optimize the interaction between the plant and its environment. Several plant terpenoids are economically important molecules that serve many applications as pharmaceuticals, pesticides, etc. Major challenges for the commercialization of plant-derived terpenoids include their low production levels in planta and the continuous demand of industry for novel molecules with new or superior biological activities. Here, we highlight several synthetic biology methods to enhance and diversify the production of plant terpenoids, with a foresight towards triterpenoid engineering, the least engineered class of bioactive terpenoids. Increased or cheaper production of valuable triterpenoids may be obtained by 'classic' metabolic engineering of plants or by heterologous production of the compounds in other plants or microbes. Novel triterpenoid structures can be generated through combinatorial biosynthesis or directed enzyme evolution approaches. In its ultimate form, synthetic biology may lead to the production of large amounts of plant triterpenoids in in vitro systems or custom-designed artificial biological systems. © 2013 The Authors. New Phytologist © 2013 New Phytologist Trust.

  18. Fundamental of biomedical engineering

    CERN Document Server

    Sawhney, GS

    2007-01-01

    About the Book: A well set out textbook explains the fundamentals of biomedical engineering in the areas of biomechanics, biofluid flow, biomaterials, bioinstrumentation and use of computing in biomedical engineering. All these subjects form a basic part of an engineer''s education. The text is admirably suited to meet the needs of the students of mechanical engineering, opting for the elective of Biomedical Engineering. Coverage of bioinstrumentation, biomaterials and computing for biomedical engineers can meet the needs of the students of Electronic & Communication, Electronic & Instrumenta

  19. Studying Engineering Practice

    DEFF Research Database (Denmark)

    Buch, Anders

    2015-01-01

    The study of engineering practices has been the focus of Engineering Studies over the last three decades. Theses studies have used ethnographic and grounded methods in order to investigate engineering practices as they unfold in natural settings - in workplaces and engineering education. However......, engineering studies have not given much attention to conceptually clarifying what should be understood by 'engineering practices' and more precisely account for the composition and organization of the entities and phenomena that make up the practices. This chapter investigates and discusses how a 'practice...... will draw out some methodological consequences and discuss the ramifications of a practice theoretical approach for Engineering Studies....

  20. Knowledge Service Engineering Handbook

    CERN Document Server

    Kantola, Jussi

    2012-01-01

    Covering the emerging field of knowledge service engineering, this groundbreaking handbook outlines how to acquire and utilize knowledge in the 21st century. Drawn on the expertise of the founding faculty member of the world's first university knowledge engineering service department, this book describes what knowledge services engineering means and how it is different from service engineering and service production. Presenting multiple cultural aspects including US, Finnish, and Korean, this handbook provides engineering, systemic, industry, and consumer use viewpoints to knowledge service sy

  1. Quantum mechanical Carnot engine

    OpenAIRE

    Bender, C.M.; Brody, D. C.; Meister, B. K.

    2000-01-01

    A cyclic thermodynamic heat engine runs most efficiently if it is reversible. Carnot constructed such a reversible heat engine by combining adiabatic and isothermal processes for a system containing an ideal gas. Here, we present an example of a cyclic engine based on a single quantum-mechanical particle confined to a potential well. The efficiency of this engine is shown to equal the Carnot efficiency because quantum dynamics is reversible. The quantum heat engine has a cycle consisting of a...

  2. Health care engineering management.

    Science.gov (United States)

    Jarzembski, W B

    1980-01-01

    Today, health care engineering management is merely a concept of dreamers, with most engineering decisions in health care being made by nonengineers. It is the purpose of this paper to present a rationale for an integrated hospital engineering group, and to acquaint the clinical engineer with some of the salient features of management concepts. Included are general management concepts, organization, personnel management, and hospital engineering systems.

  3. Gas turbine engine

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Yong Sik

    2001-08-15

    This book deals with gs turbine engine, including historical background of development of gas turbine engine, classification, definition and conception of it, torque and power, shock waves, subsonic inlets, basic turbojet cycle, turbo-shaft engine, degree of reaction, gas burner, after-burner and water injection method, design of cycle and analysis of performance, characteristic and control of engine noise of aircraft, materials and use of gas turbine engine.

  4. Mathematics in Engineering

    OpenAIRE

    Chatterjee, Anindya

    2005-01-01

    I try to convey some of the variety and excitement involved in the application of mathematics to engineering problems; to provide a taste of some actual mathematical calculations that engineers do; and finally, to make clear the distinctions between the applied subject of engineering and its purer parents, which include mathematics and the physical sciences. Two main points of this article are that in engineering it is approximation, and not truth, that reigns; and that an engineer carries a ...

  5. Mechanical engineer's handbook

    CERN Document Server

    Marghitu, Dan B

    2001-01-01

    The Mechanical Engineer's Handbook was developed and written specifically to fill a need for mechanical engineers and mechanical engineering students throughout the world. With over 1000 pages, 550 illustrations, and 26 tables the Mechanical Engineer's Handbook is very comprehensive, yet affordable, compact, and durable. The Handbook covers all major areas of mechanical engineering with succinct coverage of the definitions, formulas, examples, theory, proofs, and explanations of all principle subject areas. The Handbook is an essential, practical companion for all mechanic

  6. Biomechanical evaluation of suture holding properties of native and tissue engineered articular cartilage

    Science.gov (United States)

    DuRaine, GD; Arzi, B; Lee, JK; Lee, CA; Responte, DJ; Hu, JC; Athanasiou, KA

    2014-01-01

    Objective The purpose of this study was to determine suture-holding properties of tissue engineered neocartilage relative to native articular cartilage. To this end, suture pull-out strength was quantified for native articular cartilage and for neocartilages possessing various mechanical properties. Methods Suture holding properties were examined in vitro and in vivo. Neocartilage from bovine chondrocytes was engineered using two sets of exogenous stimuli resulting in neotissue of different biochemical compositions. Compressive and tensile properties and glycosaminoglycan, collagen, and pyridinoline cross-link contents were assayed (study 1). Suture pull-out strength was compared between neocartilage constructs, and bovine and leporine native cartilage. Uniaxial pull-out test until failure was performed after passing 6-0 Vicryl through each tissue (study 2). Subsequently, neocartilage was implanted into a rabbit model to examine short-term suture holding ability in vivo (study 3). Results Neocartilage glycosaminoglycan and collagen content per wet weight reached 4.55% ± 1.62% and 4.21 ± 0.77%, respectively. Tensile properties for neocartilage constructs reached 2.6 ± 0.77 MPa for Young’s modulus and 1.39 ± 0.63 MPa for ultimate tensile strength. Neocartilage reached ~33% of suture pull-out strength of native articular cartilage. Neocartilage cross-link content reached 50% of native values, and suture pull-out strength correlated positively with cross-link content (R2=0.74). Neocartilage sutured into rabbit osteochondral defects was successfully maintained for 3 weeks. Conclusion This study shows that pyridinoline cross-links in neocartilage may be vital in controlling suture pull-out strength. Neocartilage produced in vitro with one-third of native tissue pull-out strength appears sufficient for construct suturing and retention in vivo. PMID:24848644

  7. Future trends in agricultural engineering.

    NARCIS (Netherlands)

    Jongebreur, A.A.; Speelman, L.

    1997-01-01

    Beside traditional mechanical engineering, other engineering branches such as electronics, control engineering and physics play their specific role within the agricultural engineering field. Agricultural engineering has affected and stimulated major changes in agriculture. In the last decades

  8. Genome scale engineering techniques for metabolic engineering.

    Science.gov (United States)

    Liu, Rongming; Bassalo, Marcelo C; Zeitoun, Ramsey I; Gill, Ryan T

    2015-11-01

    Metabolic engineering has expanded from a focus on designs requiring a small number of genetic modifications to increasingly complex designs driven by advances in genome-scale engineering technologies. Metabolic engineering has been generally defined by the use of iterative cycles of rational genome modifications, strain analysis and characterization, and a synthesis step that fuels additional hypothesis generation. This cycle mirrors the Design-Build-Test-Learn cycle followed throughout various engineering fields that has recently become a defining aspect of synthetic biology. This review will attempt to summarize recent genome-scale design, build, test, and learn technologies and relate their use to a range of metabolic engineering applications. Copyright © 2015 International Metabolic Engineering Society. Published by Elsevier Inc. All rights reserved.

  9. 40 CFR 90.116 - Certification procedure-determining engine displacement, engine class, and engine families.

    Science.gov (United States)

    2010-07-01

    ... engine displacement, engine class, and engine families. 90.116 Section 90.116 Protection of Environment...-IGNITION ENGINES AT OR BELOW 19 KILOWATTS Emission Standards and Certification Provisions § 90.116 Certification procedure—determining engine displacement, engine class, and engine families. (a) Engine...

  10. Handbook of Software Engineering and Knowledge Engineering

    CERN Document Server

    2001-01-01

    This is the first handbook to cover comprehensively both software engineering and knowledge engineering - two important fields that have become interwoven in recent years. Over 60 international experts have contributed to the book. Each chapter has been written in such a way that a practitioner of software engineering and knowledge engineering can easily understand and obtain useful information. Each chapter covers one topic and can be read independently of other chapters, providing both a general survey of the topic and an in-depth exposition of the state of the art.

  11. Site systems engineering: Systems engineering management plan

    Energy Technology Data Exchange (ETDEWEB)

    Grygiel, M.L. [Westinghouse Hanford Co., Richland, WA (United States)

    1996-05-03

    The Site Systems Engineering Management Plan (SEMP) is the Westinghouse Hanford Company (WHC) implementation document for the Hanford Site Systems Engineering Policy, (RLPD 430.1) and Systems Engineering Criteria Document and Implementing Directive, (RLID 430.1). These documents define the US Department of Energy (DOE), Richland Operations Office (RL) processes and products to be used at Hanford to implement the systems engineering process at the site level. This SEMP describes the products being provided by the site systems engineering activity in fiscal year (FY) 1996 and the associated schedule. It also includes the procedural approach being taken by the site level systems engineering activity in the development of these products and the intended uses for the products in the integrated planning process in response to the DOE policy and implementing directives. The scope of the systems engineering process is to define a set of activities and products to be used at the site level during FY 1996 or until the successful Project Hanford Management Contractor (PHMC) is onsite as a result of contract award from Request For Proposal DE-RP06-96RL13200. Following installation of the new contractor, a long-term set of systems engineering procedures and products will be defined for management of the Hanford Project. The extent to which each project applies the systems engineering process and the specific tools used are determined by the project`s management.

  12. [Fabrication of bioactive tissue engineering scaffold for reconstructing calcified cartilage layer based on three-dimension printing technique].

    Science.gov (United States)

    Yu, Xinning; Fang, Jinghua; Luo, Jianyang; Yang, Xianyan; He, Dongshuang; Gou, Zhongru; Dai, Xuesong

    2016-03-01

    To fabricate organic-inorganic composite tissue engineering scaffolds for reconstructing calcified cartilage layer based on three-dimensional (3D) printing technique. The scaffolds were developed by 3D-printing technique with highly bioactive calcium-magnesium silicate ultrafine particles of 1%, 3% and 5% of mass fraction, in which the organic phases were composed of type I collagen and sodium hyaluronate. The 3D-printed scaffolds were then crosslinked and solidified by alginate and CaCl₂ aerosol. The pore size and distribution of inorganic phase were observed with scanning electron microscope (SEM); the mechanical properties were tested with universal material testing machine, and the porosity of scaffolds was also measured. Pore size was approximately (212.3 ± 34.2) μm with a porosity of (48.3 ± 5.9)%, the compressive modulus of the scaffolds was (7.2 ± 1.2) MPa, which was irrelevant to the percentage changes of calcium-magnesium silicate, the compressive modulus was between that of cartilage and subchondral bone. The porous scaffolds for calcified cartilage layer have been successfully fabricated, which would be used for multi-layered composite scaffolds in osteochondral injury.

  13. Reliability and safety engineering

    CERN Document Server

    Verma, Ajit Kumar; Karanki, Durga Rao

    2016-01-01

    Reliability and safety are core issues that must be addressed throughout the life cycle of engineering systems. Reliability and Safety Engineering presents an overview of the basic concepts, together with simple and practical illustrations. The authors present reliability terminology in various engineering fields, viz.,electronics engineering, software engineering, mechanical engineering, structural engineering and power systems engineering. The book describes the latest applications in the area of probabilistic safety assessment, such as technical specification optimization, risk monitoring and risk informed in-service inspection. Reliability and safety studies must, inevitably, deal with uncertainty, so the book includes uncertainty propagation methods: Monte Carlo simulation, fuzzy arithmetic, Dempster-Shafer theory and probability bounds. Reliability and Safety Engineering also highlights advances in system reliability and safety assessment including dynamic system modeling and uncertainty management. Cas...

  14. Humanitarian engineering in the engineering curriculum

    Science.gov (United States)

    Vandersteen, Jonathan Daniel James

    There are many opportunities to use engineering skills to improve the conditions for marginalized communities, but our current engineering education praxis does not instruct on how engineering can be a force for human development. In a time of great inequality and exploitation, the desire to work with the impoverished is prevalent, and it has been proposed to adjust the engineering curriculum to include a larger focus on human needs. This proposed curriculum philosophy is called humanitarian engineering. Professional engineers have played an important role in the modern history of power, wealth, economic development, war, and industrialization; they have also contributed to infrastructure, sanitation, and energy sources necessary to meet human need. Engineers are currently at an important point in time when they must look back on their history in order to be more clear about how to move forward. The changing role of the engineer in history puts into context the call for a more balanced, community-centred engineering curriculum. Qualitative, phenomenographic research was conducted in order to understand the need, opportunity, benefits, and limitations of a proposed humanitarian engineering curriculum. The potential role of the engineer in marginalized communities and details regarding what a humanitarian engineering program could look like were also investigated. Thirty-two semi-structured research interviews were conducted in Canada and Ghana in order to collect a pool of understanding before a phenomenographic analysis resulted in five distinct outcome spaces. The data suggests that an effective curriculum design will include teaching technical skills in conjunction with instructing about issues of social justice, social location, cultural awareness, root causes of marginalization, a broader understanding of technology, and unlearning many elements about the role of the engineer and the dominant economic/political ideology. Cross-cultural engineering development

  15. The Phillips Stirling engine

    Energy Technology Data Exchange (ETDEWEB)

    Hargreaves, C.M.

    1991-01-01

    This book is about the Stirling engine and its development from the heavy cast-iron machine of the 19th century to that of today. It is a history of a research effort spanning nearly 50 years, together with an outline of principles, and some technical details and descriptions of the more important engines. Contents include: the hot-air engine; the 20th-century revival; the Stirling cycle; rhombic-drive engines; heating and cooling; pistons and seals; electric generators and heat pumps; exotic heat sources; the engine and the environment; swashplate engines; and the past and the future.

  16. Becoming an Engineer or a Lady Engineer

    NARCIS (Netherlands)

    Liebrand, Janwillem; Udas, Pranita Bhushan

    2017-01-01

    In this article, using the Department of Irrigation in Nepal as a case study, we argue that professional performance in irrigation engineering and water resources development is gendered and normalised as ‘masculine’. In Nepal, the masculinity of professional performance in irrigation engineering is

  17. Engineering Encounters: Identifying an Engineering Design Problem

    Science.gov (United States)

    Chizek, Lisa; VanMeeteren, Beth; McDermott, Mark; Uhlenberg, Jill

    2018-01-01

    Engineering is an intriguing way for students to connect the design process with their knowledge of science (NRC 2012). This article describes the "Engineering a Pancake Recipe" design process which was created to make the structure and properties of matter more meaningful for fifth grade students. The whole pancake recipe engineering…

  18. Influence of Additive Manufactured Scaffold Architecture on the Distribution of Surface Strains and Fluid Flow Shear Stresses and Expected Osteochondral Cell Differentiation.

    Science.gov (United States)

    Hendrikson, Wim J; Deegan, Anthony J; Yang, Ying; van Blitterswijk, Clemens A; Verdonschot, Nico; Moroni, Lorenzo; Rouwkema, Jeroen

    2017-01-01

    scaffold design for tissue engineering purposes.

  19. Advanced Natural Gas Reciprocating Engine(s)

    Energy Technology Data Exchange (ETDEWEB)

    Pike, Edward

    2014-03-31

    The objective of the Cummins ARES program, in partnership with the US Department of Energy (DOE), is to develop advanced natural gas engine technologies that increase engine system efficiency at lower emissions levels while attaining lower cost of ownership. The goals of the project are to demonstrate engine system achieving 50% Brake Thermal Efficiency (BTE) in three phases, 44%, 47% and 50% (starting baseline efficiency at 36% BTE) and 0.1 g/bhp-hr NOx system out emissions (starting baseline NOx emissions at 2 – 4 g/bhp-hr NOx). Primary path towards above goals include high Brake Mean Effective Pressure (BMEP), improved closed cycle efficiency, increased air handling efficiency and optimized engine subsystems. Cummins has successfully demonstrated each of the phases of this program. All targets have been achieved through application of a combined set of advanced base engine technologies and Waste Heat Recovery from Charge Air and Exhaust streams, optimized and validated on the demonstration engine and other large engines. The following architectures were selected for each Phase: Phase 1: Lean Burn Spark Ignited (SI) Key Technologies: High Efficiency Turbocharging, Higher Efficiency Combustion System. In production on the 60/91L engines. Over 500MW of ARES Phase 1 technology has been sold. Phase 2: Lean Burn Technology with Exhaust Waste Heat Recovery (WHR) System Key Technologies: Advanced Ignition System, Combustion Improvement, Integrated Waste Heat Recovery System. Base engine technologies intended for production within 2 to 3 years Phase 3: Lean Burn Technology with Exhaust and Charge Air Waste Heat Recovery System Key Technologies: Lower Friction, New Cylinder Head Designs, Improved Integrated Waste Heat Recovery System. Intended for production within 5 to 6 years Cummins is committed to the launch of next generation of large advanced NG engines based on ARES technology to be commercialized worldwide.

  20. Siege engine dynamics

    Science.gov (United States)

    Denny, Mark

    2005-07-01

    The medieval siege engine is a historically important machine that has latterly been adopted for the purpose of physics instruction. Here we analyse the historical developments and show why these engines ultimately evolved into the highly efficient trebuchet.

  1. Chemical Engineering Education Revisited.

    Science.gov (United States)

    Theodore, Louis

    1978-01-01

    The opinion is presented that chemical engineering education seems to emphasize the professor's research and/or professional interests with little regard for the real needs of the student who intends to become a practicing engineer. (BB)

  2. Social engineering attack framework

    CSIR Research Space (South Africa)

    Mouton, F

    2014-07-01

    Full Text Available link. A social engineering attack targets this weakness by; using various manipulation techniques in order to elicit sensitive; information. The field of social engineering is still in its infancy; stages with regards to formal definitions and attack...

  3. Ice Engineering Research Area

    Data.gov (United States)

    Federal Laboratory Consortium — Refrigerated Physical Modeling of Waterways in a Controlled EnvironmentThe Research Area in the Ice Engineering Facility at the Cold Regions Research and Engineering...

  4. Minority engineering scholarships, 2012.

    Science.gov (United States)

    2014-02-01

    Scholarships for Minority Students Studying Engineering and Science: Support will make scholarships available to minority students : interested in engineering and science and will increase significantly the number of minority students that Missouri S...

  5. Genetically engineered foods

    Science.gov (United States)

    ... gene into a cell of another plant or animal. Function Genetic engineering can be done with plants, animals, or bacteria and other very small organisms. Genetic engineering allows scientists to move desired genes from ...

  6. Concrete construction engineering handbook

    CERN Document Server

    Nawy, Edward G

    2008-01-01

    Provides coverage of concrete construction engineering and technology. This work features discussions focusing on: the advances in engineered concrete materials; reinforced concrete construction; specialized construction techniques; and, design recommendations for high performance.

  7. Seeking Tomorrow's Engineers

    Science.gov (United States)

    Dickason, Donald G.

    1971-01-01

    The engineering student recently motivated primarily by the Protestant ethic, is now described as peer oriented" and other directed." The recruitment and production of engineers under new circumstances is described. (Author)

  8. Systems engineering simplified

    CERN Document Server

    Cloutier, Robert; Bone, Mary Alice

    2015-01-01

    IntroductionOverviewDiscussion of Common TerminologyThe Case for Systems EngineeringA Brief History of Systems EngineeringSystem ExamplesSummaryThe System Life CycleManaging System Development-The Vee ModelSystem ProductionSystem Utilization and SupportSystem Retirement and DisposalOther Systems Engineering Development ModelsSpiral ModelAgile Model for Systems EngineeringSystem of InterestAbstraction and DecompositionIntegrationDeveloping and Managing RequirementsCyclone Requiremen

  9. Biomedical engineering fundamentals

    CERN Document Server

    Bronzino, Joseph D

    2014-01-01

    Known as the bible of biomedical engineering, The Biomedical Engineering Handbook, Fourth Edition, sets the standard against which all other references of this nature are measured. As such, it has served as a major resource for both skilled professionals and novices to biomedical engineering.Biomedical Engineering Fundamentals, the first volume of the handbook, presents material from respected scientists with diverse backgrounds in physiological systems, biomechanics, biomaterials, bioelectric phenomena, and neuroengineering. More than three dozen specific topics are examined, including cardia

  10. Schnabel Engineering Lecture

    OpenAIRE

    Cording, Edward

    2014-01-01

    Schnabel Engineering is pleased to bring you Dr. Edward J. Cording as our eighth lecturer of this series. Dr. Cording is Professor Emeritus of Civil and Environmental Engineering at the University of Illinois at Urbana-Champaign where he has taught and performed research in geotechnical engineering, focusing on rock mechanics, soil-structure interaction, and underground construction. The field has been his laboratory, on engineering projects; beginning in the 1960's with large deep caverns ...

  11. Mechanical engineering education

    CERN Document Server

    Davim, J Paulo

    2012-01-01

    Mechanical Engineering is defined nowadays as a discipline "which involves the application of principles of physics, design, manufacturing and maintenance of mechanical systems". Recently, mechanical engineering has also focused on some cutting-edge subjects such as nanomechanics and nanotechnology, mechatronics and robotics, computational mechanics, biomechanics, alternative energies, as well as aspects related to sustainable mechanical engineering.This book covers mechanical engineering higher education with a particular emphasis on quality assurance and the improvement of academic

  12. Battery systems engineering

    CERN Document Server

    Rahn, Christopher D

    2012-01-01

    A complete all-in-one reference on the important interdisciplinary topic of Battery Systems Engineering Focusing on the interdisciplinary area of battery systems engineering, this book provides the background, models, solution techniques, and systems theory that are necessary for the development of advanced battery management systems. It covers the topic from the perspective of basic electrochemistry as well as systems engineering topics and provides a basis for battery modeling for system engineering of electric and hybrid electric vehicle platforms. This original

  13. COBRA Main Engine Project

    Science.gov (United States)

    Snoddy, Jim; Sides, Steve; Lyles, Garry M. (Technical Monitor)

    2002-01-01

    The COBRA (CO-Optimized Booster for Reusable Applications) project include the following: 1. COBRA main engine project team. 2. COBRA and RLX cycles selected. 3. COBRA proto-type engine approach enables mission success. 4. COBRA provides quick, low cost demo of cycle and technologies. 5. COBRA cycle I risk reduction supports. 6. Achieving engine safety. 6. RLX cycle I risk reduction supports. 7. Flight qualification. 9. Life extension engine testing.

  14. Object Based Systems Engineering

    Science.gov (United States)

    2011-10-17

    Based Systems Engineering ( MBSE ) has shifted the emphasis of the Systems Engineering community away from documents towards view-based artifacts. These...Engineering lies primarily in these objects, not the containers that deliver them. FIGURE 1: Evolution of Systems Engineering Practice MBSE ...capture minority viewpoints and discussion threads associated with each object of interest. If the majority view doesn’t lead to success, this data may

  15. Electronics engineer's reference book

    CERN Document Server

    Turner, L W

    1976-01-01

    Electronics Engineer's Reference Book, 4th Edition is a reference book for electronic engineers that reviews the knowledge and techniques in electronics engineering and covers topics ranging from basics to materials and components, devices, circuits, measurements, and applications. This edition is comprised of 27 chapters; the first of which presents general information on electronics engineering, including terminology, mathematical equations, mathematical signs and symbols, and Greek alphabet and symbols. Attention then turns to the history of electronics; electromagnetic and nuclear radiatio

  16. Aircraft engine noise

    Science.gov (United States)

    Kennepohl, F.

    An overview of the main aircraft engine noise sources is given. Special emphasis is devoted to turbomachinery/rotor noise, which plays an important role in all engine concepts appropriate to regional aircraft, such as turbofans, propellers, or new propfan engine concepts. The noise generating mechanisms, including propagation within the engine, and calculation methods used are described. Noise reduction methods are considered, with emphasis on cutoff design of turbomachines. Some noise features of counter rotating propellers and swept rotor blades are mentioned.

  17. Efficient homologous recombination-mediated genome engineering in zebrafish using TALE nucleases.

    Science.gov (United States)

    Shin, Jimann; Chen, Jiakun; Solnica-Krezel, Lilianna

    2014-10-01

    Custom-designed nucleases afford a powerful reverse genetic tool for direct gene disruption and genome modification in vivo. Among various applications of the nucleases, homologous recombination (HR)-mediated genome editing is particularly useful for inserting heterologous DNA fragments, such as GFP, into a specific genomic locus in a sequence-specific fashion. However, precise HR-mediated genome editing is still technically challenging in zebrafish. Here, we establish a GFP reporter system for measuring the frequency of HR events in live zebrafish embryos. By co-injecting a TALE nuclease and GFP reporter targeting constructs with homology arms of different size, we defined the length of homology arms that increases the recombination efficiency. In addition, we found that the configuration of the targeting construct can be a crucial parameter in determining the efficiency of HR-mediated genome engineering. Implementing these modifications improved the efficiency of zebrafish knock-in generation, with over 10% of the injected F0 animals transmitting gene-targeting events through their germline. We generated two HR-mediated insertion alleles of sox2 and gfap loci that express either superfolder GFP (sfGFP) or tandem dimeric Tomato (tdTomato) in a spatiotemporal pattern that mirrors the endogenous loci. This efficient strategy provides new opportunities not only to monitor expression of endogenous genes and proteins and follow specific cell types in vivo, but it also paves the way for other sophisticated genetic manipulations of the zebrafish genome. © 2014. Published by The Company of Biologists Ltd.

  18. Contact guidance for cardiac tissue engineering using 3D bioprinted gelatin patterned hydrogel.

    Science.gov (United States)

    Tijore, Ajay; Irvine, Scott Alexander; Sarig, Udi; Mhaisalkar, Priyadarshini; Baisane, Vrushali; Venkatraman, Subbu S

    2017-12-13

    Here, we have developed a 3D bioprinted microchanneled gelatin hydrogel that promotes human mesenchymal stem cell (hMSC) myocardial commitment and supports native cardiomyocytes (CMs) contractile functionality. Firstly, we studied the effect of bioprinted microchanneled hydrogel on the alignment, elongation, and differentiation of hMSC. Notably, the cells displayed well defined F-actin anisotropy and elongated morphology on the microchanneled hydrogel, hence showing the effects of topographical control over cell behavior. Furthermore, the aligned stem cells showed myocardial lineage commitment, as detected using mature cardiac markers. The fluorescence-activated cell sorting (FACS) analysis also confirmed a significant increase in the commitment towards myocardial tissue lineage. Moreover, seeded CMs were found to be more aligned and demonstrated synchronized beating on microchanneled hydrogel as compared to the unpatterned hydrogel. Overall, our study proved that microchanneled hydrogel scaffold produced by 3D bioprinting induces myocardial differentiation of stem cells as well as supports CMs growth and contractility. Applications of this approach may be beneficial for generating in vitro cardiac model systems to physiological and cardiotoxicity studies, as well as in vivo generating custom designed cell impregnated constructs for tissue engineering and regenerative medicine applications. Creative Commons Attribution license.

  19. Vascularization Tissue Engineering

    NARCIS (Netherlands)

    Rouwkema, Jeroen; Rivron, N.C.; van Blitterswijk, Clemens

    2008-01-01

    Tissue engineering has been an active field of research for several decades now. However, the amount of clinical applications in the field of tissue engineering is still limited. One of the current limitations of tissue engineering is its inability to provide sufficient blood supply in the initial

  20. Principles of Naval Engineering.

    Science.gov (United States)

    Naval Personnel Program Support Activity, Washington, DC.

    Fundamentals of shipboard machinery, equipment, and engineering plants are presented in this text prepared for engineering officers. A general description is included of the development of naval ships, ship design and construction, stability and buoyancy, and damage and casualty control. Engineering theories are explained on the background of ship…

  1. Women in Engineering

    Science.gov (United States)

    Maurice, H. M.

    1977-01-01

    This discussion of the history of women in engineering in Great Britain covers (1) the founding and activities of the Women's Engineering Society, (2) women engineers in the 1930's, in wartime, in the postwar period, in the present, and in the future, and (3) attitudes about sex roles in the face of changing social values. (SH)

  2. Alternate fuels for engines

    Energy Technology Data Exchange (ETDEWEB)

    Sundaram, P.S.N.

    1981-06-01

    Field trials with SVC 5, single-cylinder, high-speed diesel engines have been conducted by Cooper Engineering Ltd, substituting alcohol, gobar gas and LPG, one by one, for diesel oil. The experiments have shown that the engines can be successfully operated with one of the three alternate fuels after making minor modifications in their design.

  3. Kali Linux social engineering

    CERN Document Server

    Singh, Rahul

    2013-01-01

    This book is a practical, hands-on guide to learning and performing SET attacks with multiple examples.Kali Linux Social Engineering is for penetration testers who want to use BackTrack in order to test for social engineering vulnerabilities or for those who wish to master the art of social engineering attacks.

  4. Engineering honours program

    NARCIS (Netherlands)

    Ir Antoine waal; Ir. Peter van Kollenburg

    2011-01-01

    In September 2009 the department of Engineering of Fontys University of Applied Sciences in the Netherlands has started a pilot honours program for excellent engineering students called PRogram OUstanding Development (PROUD). Aim of this program is to give those engineering students, who have the

  5. Engineering Knowledge Management

    DEFF Research Database (Denmark)

    Wallace, Ken M.; Ahmed, Saeema; Bracewell, Rob

    2005-01-01

    The need to improve engineering knowledge management is driven by the current challenges facing manufacturing organisations in the emerging global economy and, in particular by the important role knowledge plays in the engineering design process. Industrial organisations are facing increasing...... international competition, and in response their engineering products are improving in terms of performance, reliability and cost of ownership....

  6. Hybrid intelligent engineering systems

    CERN Document Server

    Jain, L C; Adelaide, Australia University of

    1997-01-01

    This book on hybrid intelligent engineering systems is unique, in the sense that it presents the integration of expert systems, neural networks, fuzzy systems, genetic algorithms, and chaos engineering. It shows that these new techniques enhance the capabilities of one another. A number of hybrid systems for solving engineering problems are presented.

  7. The Engineers' Innovation Toolkit

    NARCIS (Netherlands)

    Bonnema, Gerrit Maarten; Vaneker, T.H.J.; Lutters, D.

    2008-01-01

    Most engineers nowadays receive a mono-disciplinary education: Mechanical engineering, Electrical engineering etc. Contradictory, the products they have to design are ever more multidisciplinary and integrated. This requires a different mindset. This paper discusses four tools that fit in the

  8. Sound Search Engine Concept

    DEFF Research Database (Denmark)

    2006-01-01

    Sound search is provided by the major search engines, however, indexing is text based, not sound based. We will establish a dedicated sound search services with based on sound feature indexing. The current demo shows the concept of the sound search engine. The first engine will be realased June...

  9. Ethics and engineering design.

    NARCIS (Netherlands)

    van de Poel, I.R.; van der Poel, Ibo; Verbeek, Peter P.C.C.

    2006-01-01

    Engineering ethics and science and technology studies (STS) have until now developed as separate enterprises. The authors argue that they can learn a lot from each other. STS insights can help make engineering ethics open the black box of technology and help discern ethical issues in engineering

  10. Designing requirements engineering research

    NARCIS (Netherlands)

    Wieringa, Roelf J.; Heerkens, Johannes M.G.

    2007-01-01

    Engineering sciences study different topics than natural sciences, and utility is an essential factor in choosing engineering research problems. But despite these differences, research methods for the engineering sciences are no different than research methods for any other kind of science. At most

  11. Modern engineering thermodynamics

    CERN Document Server

    Balmer, Robert T

    2010-01-01

    Designed for use in a standard two-semester engineering thermodynamics course sequence. The first half of the text contains material suitable for a basic Thermodynamics course taken by engineers from all majors. The second half of the text is suitable for an Applied Thermodynamics course in mechanical engineering programs. The text has numerous features that are unique among engineering textbooks, including historical vignettes, critical thinking boxes, and case studies. All are designed to bring real engineering applications into a subject that can be somewhat abstract and mathematica

  12. CF 6 engine diagnostics

    Science.gov (United States)

    Stricklin, R.

    1981-01-01

    A summary of the activities which led to defining deterioration rates of the CF6 family of engines, a description of what was learned, and an identification of means of conserving fuel based upon the program findings are presented. The program to define the deterioration levels and modes for the CF6 family of engines involved four distinct phases: analysis of inbound engine test results, analysis of airline cruise data, analysis of airline test cell data resulting from testing of refurbished engines, and inspection of engine hardware.

  13. Integrative metabolic engineering

    Directory of Open Access Journals (Sweden)

    George H McArthur IV

    2015-07-01

    Full Text Available Recent advances in experimental and computational synthetic biology are extremely useful for achieving metabolic engineering objectives. The integration of synthetic biology and metabolic engineering within an iterative design-build-test framework will improve the practice of metabolic engineering by relying more on efficient design strategies. Computational tools that aid in the design and in silico simulation of metabolic pathways are especially useful. However, software helpful for constructing, implementing, measuring and characterizing engineered pathways and networks should not be overlooked. In this review, we highlight computational synthetic biology tools relevant to metabolic engineering, organized in the context of the design-build-test cycle.

  14. Programming Google App Engine

    CERN Document Server

    Sanderson, Dan

    2010-01-01

    As one of today's cloud computing services, Google App Engine does more than provide access to a large system of servers. It also offers you a simple model for building applications that scale automatically to accommodate millions of users. With Programming Google App Engine, you'll get expert practical guidance that will help you make the best use of this powerful platform. Google engineer Dan Sanderson shows you how to design your applications for scalability, including ways to perform common development tasks using App Engine's APIs and scalable services. You'll learn about App Engine's a

  15. Handbook of Engineering Acoustics

    CERN Document Server

    Möser, Michael

    2013-01-01

    This book examines the physical background of engineering acoustics, focusing on empirically obtained engineering experience as well as on measurement techniques and engineering methods for prognostics. Its goal is not only to describe the state of art of engineering acoustics but also to give practical help to engineers in order to solve acoustic problems. It deals with the origin, the transmission and the methods of the abating different kinds of air-borne and structure-borne sounds caused by various mechanisms – from traffic to machinery and flow-induced sound. In addition the modern aspects of room and building acoustics, as well as psychoacoustics and active noise control, are covered.

  16. Controlling surface microstructure of calcium phosphate ceramic from random to custom-design

    NARCIS (Netherlands)

    Wang, Liao; Luo, Xiaoman; Barbieri, D.; Bao, Chongyun; Yuan, Huipin

    2014-01-01

    Calcium phosphate ceramics have long been studied as bone graft substitutes due to their similarity with the mineral constitute of bone and teeth, excellent biocompatibility and bioactivity. Chemical composition, macrostructure and surface microstructure are believed to be important for the bone

  17. A high quality finger vascular pattern dataset collected using a custom designed capturing device

    NARCIS (Netherlands)

    Ton, B.T.; Veldhuis, Raymond N.J.

    2013-01-01

    The number of finger vascular pattern datasets available for the research community is scarce, therefore a new finger vascular pattern dataset containing 1440 images is prsented. This dataset is unique in its kind as the images are of high resolution and have a known pixel density. Furthermore this

  18. A new nanocomposite forward osmosis membrane custom-designed for treating shale gas wastewater

    Science.gov (United States)

    Qin, Detao; Liu, Zhaoyang; Delai Sun, Darren; Song, Xiaoxiao; Bai, Hongwei

    2015-09-01

    Managing the wastewater discharged from oil and shale gas fields is a big challenge, because this kind of wastewater is normally polluted by high contents of both oils and salts. Conventional pressure-driven membranes experience little success for treating this wastewater because of either severe membrane fouling or incapability of desalination. In this study, we designed a new nanocomposite forward osmosis (FO) membrane for accomplishing simultaneous oil/water separation and desalination. This nanocomposite FO membrane is composed of an oil-repelling and salt-rejecting hydrogel selective layer on top of a graphene oxide (GO) nanosheets infused polymeric support layer. The hydrogel selective layer demonstrates strong underwater oleophobicity that leads to superior anti-fouling capability under various oil/water emulsions, and the infused GO in support layer can significantly mitigate internal concentration polarization (ICP) through reducing FO membrane structural parameter by as much as 20%. Compared with commercial FO membrane, this new FO membrane demonstrates more than three times higher water flux, higher removals for oil and salts (>99.9% for oil and >99.7% for multivalent ions) and significantly lower fouling tendency when investigated with simulated shale gas wastewater. These combined merits will endorse this new FO membrane with wide applications in treating highly saline and oily wastewaters.

  19. Evaluation of a Biologic Formulation Using Customized Design of Experiment and Novel Multidimensional Robustness Diagrams.

    Science.gov (United States)

    Maroju, Radhakrishna K; Barash, Steve; Brisbane, Charlene E

    2017-10-26

    Formulation development includes selection of appropriate excipients to stabilize the active pharmaceutical ingredient throughout its recommended shelf life, against potential excursions in its life cycle and sometimes to aid in the delivery of therapeutics into the patient. Identity and quantity of every ingredient in a therapeutic formulation are critical to achieve their intended purpose. Deviations from a target composition can result in manufacturing, safety, and efficacy challenges. It is mandatory to establish robustness of a formulation for the expected changes in its composition arising from the qualified "process variability" of the impacting process steps during manufacture. The approach for carrying out a robustness study evolved through improved understanding of a therapeutic stability and exploration of new tools, including the quality by design elements strongly recommended by regulatory agencies. An approach is presented here to study formulation robustness in multidimensional space using a customized experimental design and novel multidimensional diagrams, which present a unique way of identifying robustness limits. The concept is universally applicable to any multivariate analysis and such diagrams would be useful to comprehend the outcome on all variables at a glance. Interpretation of these diagrams is discussed, some of which are applicable in general to any statistical design of experiment. Copyright © 2017 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

  20. A new nanocomposite forward osmosis membrane custom-designed for treating shale gas wastewater

    Science.gov (United States)

    Qin, Detao; Liu, Zhaoyang; Delai Sun, Darren; Song, Xiaoxiao; Bai, Hongwei

    2015-01-01

    Managing the wastewater discharged from oil and shale gas fields is a big challenge, because this kind of wastewater is normally polluted by high contents of both oils and salts. Conventional pressure-driven membranes experience little success for treating this wastewater because of either severe membrane fouling or incapability of desalination. In this study, we designed a new nanocomposite forward osmosis (FO) membrane for accomplishing simultaneous oil/water separation and desalination. This nanocomposite FO membrane is composed of an oil-repelling and salt-rejecting hydrogel selective layer on top of a graphene oxide (GO) nanosheets infused polymeric support layer. The hydrogel selective layer demonstrates strong underwater oleophobicity that leads to superior anti-fouling capability under various oil/water emulsions, and the infused GO in support layer can significantly mitigate internal concentration polarization (ICP) through reducing FO membrane structural parameter by as much as 20%. Compared with commercial FO membrane, this new FO membrane demonstrates more than three times higher water flux, higher removals for oil and salts (>99.9% for oil and >99.7% for multivalent ions) and significantly lower fouling tendency when investigated with simulated shale gas wastewater. These combined merits will endorse this new FO membrane with wide applications in treating highly saline and oily wastewaters. PMID:26416014

  1. Structural and mechanical characterization of custom design cranial implant created using additive manufacturing

    Directory of Open Access Journals (Sweden)

    Khaja Moiduddin

    2017-09-01

    Conclusions: The study reveals that the use of mesh implants in cranial reconstruction satisfies the need of lighter implants with an adequate mechanical strength, thus restoring better functionality and esthetic outcomes for the patients.

  2. A comparative study on the customized design of mandibular reconstruction plates using finite element method

    Directory of Open Access Journals (Sweden)

    Abdulrahman Al-Ahmari

    2015-07-01

    Full Text Available Mandible defects and its deformities are serious complications and its precise reconstruction is one of the most challenging tasks in oral maxillofacial surgery. The commercially available standard mandible implants are manually bended before surgery to custom fit the patient’s jaw. A slight mismatch in the plate and bone alignment may result in the implant failure. However, with the integration of computer-aided design, rapid prototyping, and advanced imaging systems (computed tomography or magnetic resonance imaging, it is possible to produce a customized mandible implant that can precisely fit the patient’s jaw. The aim of this article is to compare a new design of customized mandible implant (sinewave plate and compare it with the commonly used straight implant design. The finite element–simulated results reveal that the commonly used straight reconstruction plates are more prone to loosening of the screws due to its higher strain concentration on the screw hole when compared to newly designed sinewave reconstruction plate. Moreover, the straight plate is more sensitive to the chewing load variations and develops almost 20% increase in the stresses when compared to sinewave plate. The study reveals that the sinewave reconstruction plate can significantly enhance the stability and safety of the mandible implant.

  3. Full Custom Design of a 8-bit Subranging Flash A/D Convertor

    Directory of Open Access Journals (Sweden)

    J. Sevenhans

    1993-07-01

    Full Text Available This paper describes the design of a Nonius Flash Analog to Digital Convertor for video-applications. The conversion is split up in two stages: the MSB and the LSB conversion stage. In the LSB conversion stage, the reference-voltage for the comparators is shifted up and down as a nonius of a vernier gauge, according to the MSB conversion obtained in the first half clock cycle. The MSB's and LSB's are simultaneously available at the output to make a 8-bit representation of the analog signal. Using the subranging mechanism, the number of comparators is reduced from 256 to 32 and the Nonius approach results in a very simple configuration for the subranging switches. The design has been simulated with HSPICE in ES2 1. 5 CMOS technology.

  4. Virtual learning engine for electrical engineering education

    Science.gov (United States)

    Lord, Robert; Chapman, Brian

    1999-09-01

    Making the conceptual change from electricity as electrons moving in wires under the influence of voltage to electromagnetic energy embracing light and radio waves, using a mathematical learning sequence, has proven to be difficult for learners over the years. A `virtual learning engine' has been created to help begin this conceptual change in students' understanding of electricity by supporting the mathematical sequence with interactive action learning exercises and real world experimental observations. Development of the `virtual learning engine' is informed by current educational research and motivated primarily by the thrust into online education. Extensive consideration and assessment of learner desires led to clear goals and objectives providing a rigid framework for the `virtual learning engine' development. However, a flexible specification enabled creative input from both the academic and the software engineer. The result is an educationally sound flexible learning resource suitable for use by on- campus and off-campus students.

  5. Teaching optical engineering to electrical engineering undergraduates

    Science.gov (United States)

    Boreman, Glenn D.

    1997-12-01

    We describe a one-semester undergraduate course in optical engineering that has been taught at University of Central Florida since 1985 to junior and senior students of electrical engineering. The choice of topics emphasizes first-order system-engineering calculations, rather than the more traditional theoretical viewpoint often found in junior/senior-level optics courses. Representative topics include: paraxial raytracing, field of view and F/#, diffraction-limited resolution, Fresnel equations, radiometric/photometric units, paraxial flux transfer, blackbody radiation, detector responsivity and sensitivity, shot noise, Johnson noise, and laser-beam propagation. Homework problems emphasize estimation of magnitudes, as well as more exact numerical calculations. We have found this approach to be accessible to typical engineering undergraduates, and to be a good foundation for entry-level practitioners.

  6. Engineered phages for electronics.

    Science.gov (United States)

    Cui, Yue

    2016-11-15

    Phages are traditionally widely studied in biology and chemistry. In recent years, engineered phages have attracted significant attentions for functionalization or construction of electronic devices, due to their specific binding, catalytic, nucleating or electronic properties. To apply the engineered phages in electronics, these are a number of interesting questions: how to engineer phages for electronics? How are the engineered phages characterized? How to assemble materials with engineered phages? How are the engineered phages micro or nanopatterned? What are the strategies to construct electronics devices with engineered phages? This review will highlight the early attempts to address these questions and explore the fundamental and practical aspects of engineered phages in electronics, including the approaches for selection or expression of specific peptides on phage coat proteins, characterization of engineered phages in electronics, assembly of electronic materials, patterning of engineered phages, and construction of electronic devices. It provides the methodologies and opens up ex-cit-ing op-por-tu-ni-ties for the development of a variety of new electronic materials and devices based on engineered phages for future applications. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. Driving and engine cycles

    CERN Document Server

    Giakoumis, Evangelos G

    2017-01-01

    This book presents in detail the most important driving and engine cycles used for the certification and testing of new vehicles and engines around the world. It covers chassis and engine-dynamometer cycles for passenger cars, light-duty vans, heavy-duty engines, non-road engines and motorcycles, offering detailed historical information and critical review. The book also provides detailed examples from SI and diesel engines and vehicles operating during various cycles, with a focus on how the engine behaves during transients and how this is reflected in emitted pollutants, CO2 and after-treatment systems operation. It describes the measurement methods for the testing of new vehicles and essential information on the procedure for creating a driving cycle. Lastly, it presents detailed technical specifications on the most important chassis-dynamometer cycles around the world, together with a direct comparison of those cycles.

  8. Systems Engineering Analysis

    Directory of Open Access Journals (Sweden)

    Alexei Serna M.

    2013-07-01

    Full Text Available The challenges proposed by the development of the new computer systems demand new guidance related to engineer´s education, because they will solve these problems. In the XXI century, system engineers must be able to integrate a number of topics and knowledge disciplines that complement that traditionally has been known as Computer Systems Engineering. We have enough software development engineers, today we need professional engineers for software integration, leaders and system architects that make the most of the technological development for the benefit of society, leaders that integrate sciences to the solutions they build and propose. In this article the current situation of Computer Systems Engineering is analyzed and is presented a theory proposing the need for modifying the approach Universities have given to these careers, to achieve the education of leader engineers according to the needs of this century.

  9. Culture in Engineering Education

    DEFF Research Database (Denmark)

    Hoffmann, Birgitte; Jørgensen, Ulrik; Christensen, Hans Peter

    2011-01-01

    As engineers today often work in intercultural projects and contexts, intercultural competences must be part of the learning objectives in engineering educations. Cultural aspects of engineering education should not just be treated as a question of appropriate communication and teaching: cultural...... to cultural aspects in engineering education. Hence the key-question of this paper is how CDIO support the development of intercultural competences in engineering education. The paper explores the implementation of CDIO in an intercultural arctic engineering programme in Greenland that since 2001 has been...... enrolling students with special focus on developing intercultural competences. The discussion draws on the socio-technical approaches to technology and professional engineering practises [5,6]. We conclude that intercultural teaching is not just a matter of teaching in spite of cultural differences...

  10. Da "Search engines" a "Shop engines"

    OpenAIRE

    Lupi, Mauro

    2001-01-01

    The change occuring related to “search engines” is going towards e-commerce, transforming all the main search engines into information and commercial suggestion conveying means, basing their businnes on this activity. In a next future we will find two main series of search engines: from one side, the portals that will offer a general orientation guide being convoying means for services and to-buy products; from the other side, vertical portals able to offer information and products on specifi...

  11. Mechanical Engineering Department technical review

    Energy Technology Data Exchange (ETDEWEB)

    Carr, R.B.; Abrahamson, L.; Denney, R.M.; Dubois, B.E (eds.)

    1982-01-01

    Technical achievements and publication abstracts related to research in the following Divisions of Lawrence Livermore Laboratory are reported in this biannual review: Nuclear Fuel Engineering; Nuclear Explosives Engineering; Weapons Engineering; Energy Systems Engineering; Engineering Sciences; Magnetic Fusion Engineering; and Material Fabrication. (LCL)

  12. Systems Engineering Management and the Relationship of Systems Engineering to Project Management and Software Engineering (presentation)

    OpenAIRE

    Boehm, Barry; Conrow, Ed; Madachy, Ray; Nidiffer, Ken; Roedler, Garry

    2010-01-01

    Prepared for the 13th Annual NDIA Systems Engineering Conference October 28, 2010, “Achieving Acquisition Excellence Via Effective Systems Engineering”. Panel: Systems Engineering Management and the Relationship of Systems Engineering to Project Management and Software Engineering

  13. Analysis of the in vitro degradation and the in vivo tissue response to bi-layered 3D-printed scaffolds combining PLA and biphasic PLA/bioglass components – Guidance of the inflammatory response as basis for osteochondral regeneration

    Directory of Open Access Journals (Sweden)

    Mike Barbeck

    2017-12-01

    Altogether, the results showed that the addition of G5 enables to reduce scaffold weight loss and to increase mechanical strength. Furthermore, the addition of G5 lead to a higher vascularization of the implant bed required as basis for bone tissue regeneration mediated by higher numbers of BMGCs, while within the PLA parts a significantly lower vascularization was found optimally for chondral regeneration. Thus, this data show that the analyzed bi-layered scaffold may serve as an ideal basis for the regeneration of osteochondral tissue defects. Additionally, the results show that it might be able to reduce the number of experimental animals required as it may be possible to analyze the tissue response to more than one implant in one experimental animal.

  14. The interest of bone scintigraphy in diagnosis and monitoring in primitive osteo-chondritis of the hip; Interet de l'utilisation de la scintigraphie osseuse dans le diagnostic et le suivi de l'osteochondrite primitive de la hanche

    Energy Technology Data Exchange (ETDEWEB)

    Oufroukhi, Y.; Biyi, A.; Doudouh, A. [Hopital Militaire d' Instruction Med V, Hay Riad, Service de Medecine Nucleaire, Rabat (Morocco)

    2009-02-15

    Osteo-chondritis, or Legg-Calve-Perthes disease (L.C.P.), is a necrosis of the proximal femoral epiphysis. This vascular accident entails on the complex phenomenon of growth of the child's hip and can result in deformations or even a strict destruction of the proximal femoral epiphysis. The aim of this article is to show the interest of the bone scintigraphy (B.S.) in precocious diagnosis and follow-up of L.C.P. disease. In this aim, we introduced a clinical case of L.C.P. disease where B.S. allowed a precocious diagnosis and a stringent monitoring. Discussion of case includes a systematic review of literature. (authors)

  15. Modification of Diesel Engine to Producer Gas Engine

    OpenAIRE

    Aung, Nay Zar

    2012-01-01

    This paper describes considerations and procedure of conversion from diesel engine to producer gas engine. In this paper, the performance of producer gas engine is compared to the original diesel engine and the factors affecting on performance of the producer gas engine are mentioned. After converting the 26.5 kW diesel engines to producer gas engine, the power output of producer gas engine is 40% less than that of original diesel engine. However producer gas engines are used for saving fuel ...

  16. Practical electrical engineering

    CERN Document Server

    N Makarov, Sergey; Bitar, Stephen J

    2016-01-01

    This textbook provides comprehensive, in-depth coverage of the fundamental concepts of electrical and computer engineering. It is written from an engineering perspective, with special emphasis on circuit functionality and applications. Reliance on higher-level mathematics and physics, or theoretical proofs has been intentionally limited in order to prioritize the practical aspects of electrical engineering. This text is therefore suitable for a number of introductory circuit courses for other majors such as robotics, mechanical, biomedical, aerospace, civil, architecture, petroleum, and industrial engineering. The authors’ primary goal is to teach the aspiring engineering student all fundamental tools needed to understand, analyze and design a wide range of practical circuits and systems. Their secondary goal is to provide a comprehensive reference, for both major and non-major students as well as practicing engineers. Provides a self-contained, fundamental textbook on electric circuits and basic electronic...

  17. Nanotechnology for chemical engineers

    CERN Document Server

    Salaheldeen Elnashaie, Said; Hashemipour Rafsanjani, Hassan

    2015-01-01

    The book describes the basic principles of transforming nano-technology into nano-engineering with a particular focus on chemical engineering fundamentals. This book provides vital information about differences between descriptive technology and quantitative engineering for students as well as working professionals in various fields of nanotechnology. Besides chemical engineering principles, the fundamentals of nanotechnology are also covered along with detailed explanation of several specific nanoscale processes from chemical engineering point of view. This information is presented in form of practical examples and case studies that help the engineers and researchers to integrate the processes which can meet the commercial production. It is worth mentioning here that, the main challenge in nanostructure and nanodevices production is nowadays related to the economic point of view. The uniqueness of this book is a balance between important insights into the synthetic methods of nano-structures and nanomaterial...

  18. Embedded engineering education

    CERN Document Server

    Kaštelan, Ivan; Temerinac, Miodrag; Barak, Moshe; Sruk, Vlado

    2016-01-01

    This book focuses on the outcome of the European research project “FP7-ICT-2011-8 / 317882: Embedded Engineering Learning Platform” E2LP. Additionally, some experiences and researches outside this project have been included. This book provides information about the achieved results of the E2LP project as well as some broader views about the embedded engineering education. It captures project results and applications, methodologies, and evaluations. It leads to the history of computer architectures, brings a touch of the future in education tools and provides a valuable resource for anyone interested in embedded engineering education concepts, experiences and material. The book contents 12 original contributions and will open a broader discussion about the necessary knowledge and appropriate learning methods for the new profile of embedded engineers. As a result, the proposed Embedded Computer Engineering Learning Platform will help to educate a sufficient number of future engineers in Europe, capable of d...

  19. Engineering and design skills

    DEFF Research Database (Denmark)

    Schrøder, Anne Lise

    2006-01-01

    In various branches of society there is focus on the need for design skills and innovation potential as a means of communicating and handling constant change. In this context, the traditional idea of the engineer as a poly-technician inventing solutions by understanding the laws of nature...... concept of diagrammatic reasoning to some extent incarnates the very method of engineering and design. On this background, it is argued how the work field and techniques of the engineer and the engineering scientist could be characterized in a broader creative context of learning and communication....... This leads to considering the fundamental skills of the engineering practice as basic abilities to see the structures and dynamics of the world, to model it, and to create new solutions concerning practical as well as theoretical matters. Finally, it is assumed that the essence of engineering “bildung...

  20. Staged combustion with piston engine and turbine engine supercharger

    Science.gov (United States)

    Fischer, Larry E [Los Gatos, CA; Anderson, Brian L [Lodi, CA; O'Brien, Kevin C [San Ramon, CA

    2011-11-01

    A combustion engine method and system provides increased fuel efficiency and reduces polluting exhaust emissions by burning fuel in a two-stage combustion system. Fuel is combusted in a piston engine in a first stage producing piston engine exhaust gases. Fuel contained in the piston engine exhaust gases is combusted in a second stage turbine engine. Turbine engine exhaust gases are used to supercharge the piston engine.

  1. Standing detonation wave engine

    KAUST Repository

    Kasimov, Aslan

    2015-10-08

    A detonation engine can detonate a mixture of fuel and oxidizer within a cylindrical detonation region to produce work. The detonation engine can have a first and a second inlet having ends fluidly connected from tanks to the detonation engine. The first and second inlets can be aligned along a common axis. The inlets can be connected to nozzles and a separator can be positioned between the nozzles and along the common axis.

  2. Electrical engineer's reference book

    CERN Document Server

    Laughton, M A

    1985-01-01

    Electrical Engineer's Reference Book, Fourteenth Edition focuses on electrical engineering. The book first discusses units, mathematics, and physical quantities, including the international unit system, physical properties, and electricity. The text also looks at network and control systems analysis. The book examines materials used in electrical engineering. Topics include conducting materials, superconductors, silicon, insulating materials, electrical steels, and soft irons and relay steels. The text underscores electrical metrology and instrumentation, steam-generating plants, turbines

  3. Vehicular Engine Design

    Science.gov (United States)

    Hoag, Kevin L.

    This book provides an introduction to the design and mechanical development of reciprocating piston engines for vehicular applications. Beginning from the determination of required displacement, coverage moves into engine configuration and architecture. Critical layout dimensions and design trade-offs are then presented. Coverage continues with material and casting process selection for the cylinder block and heads. Each major engine component and sub-system is then taken up in turn.

  4. Isolated quantum heat engine.

    Science.gov (United States)

    Fialko, O; Hallwood, D W

    2012-02-24

    We present a theoretical and numerical analysis of a quantum system that is capable of functioning as a heat engine. This system could be realized experimentally using cold bosonic atoms confined to a double well potential that is created by splitting a harmonic trap with a focused laser. The system shows thermalization, and can model a reversible heat engine cycle. This is the first demonstration of the operation of a heat engine with a finite quantum heat bath.

  5. Isolated quantum heat engine

    OpenAIRE

    Fialko, O.; Hallwood, D.

    2011-01-01

    We present a theoretical and numerical analysis of a quantum system that is capable of functioning as a heat engine. This system could be realized experimentally using cold bosonic atoms confined to a double well potential that is created by splitting a harmonic trap with a focused laser. The system shows thermalization, and can model a reversible heat engine cycle. This is the first demonstration of the operation of a heat engine with a finite quantum heat bath.

  6. Integrative metabolic engineering

    OpenAIRE

    George H McArthur IV; Pooja P Nanjannavar; Emily H Miller; Stephen S. Fong

    2015-01-01

    Recent advances in experimental and computational synthetic biology are extremely useful for achieving metabolic engineering objectives. The integration of synthetic biology and metabolic engineering within an iterative design-build-test framework will improve the practice of metabolic engineering by relying more on efficient design strategies. Computational tools that aid in the design and in silico simulation of metabolic pathways are especially useful. However, software helpful for constru...

  7. Software engineer's pocket book

    CERN Document Server

    Tooley, Michael

    2013-01-01

    Software Engineer's Pocket Book provides a concise discussion on various aspects of software engineering. The book is comprised of six chapters that tackle various areas of concerns in software engineering. Chapter 1 discusses software development, and Chapter 2 covers programming languages. Chapter 3 deals with operating systems. The book also tackles discrete mathematics and numerical computation. Data structures and algorithms are also explained. The text will be of great use to individuals involved in the specification, design, development, implementation, testing, maintenance, and qualit

  8. Engine Cold Start

    Science.gov (United States)

    2015-09-01

    UNCLASSIFIED UNCLASSIFIED ENGINE COLD START INTERIM REPORT TFLRF No. 469 by Douglas M. Yost Gregory A. T. Hansen U.S...not return it to the originator. UNCLASSIFIED UNCLASSIFIED ENGINE COLD START INTERIM REPORT TFLRF No. 469 by Douglas M. Yost...TITLE AND SUBTITLE Engine Cold Start 5a. CONTRACT NUMBER W56HZV-09-C-0100 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) Douglas

  9. Game engines: a survey

    OpenAIRE

    A. Andrade

    2015-01-01

    Due to hardware limitations at the origin of the video game industry, each new game was generally coded from the ground up. Years later, from the evolution of hardware and the need for quick game development cycles, spawned the concept of game engine. A game engine is a reusable software layer allowing the separation of common game concepts from the game assets (levels, graphics, etc.). This paper surveys fourteen different game engines relevant today, ranging from the industry-level to the n...

  10. Game mechanics engine

    OpenAIRE

    Magnusson, Lars V

    2011-01-01

    Game logic and game rules exists in all computer games, but they are created di erently for all game engines. This game engine dependency exists because of how the internal object model is implemented in the engine, as a place where game logic data is intermingled with the data needed by the low- level subsystems. This thesis propose a game object model design, based on existing theory, that removes this dependency and establish a general game logic framework. The thesis the...

  11. Tokamak engineering mechanics

    CERN Document Server

    Song, Yuntao; Du, Shijun

    2013-01-01

    Tokamak Engineering Mechanics offers concise and thorough coverage of engineering mechanics theory and application for tokamaks, and the material is reinforced by numerous examples. Chapter topics include general principles, static mechanics, dynamic mechanics, thermal fluid mechanics and multiphysics structural mechanics of tokamak structure analysis. The theoretical principle of the design and the methods of the analysis for various components and load conditions are presented, while the latest engineering technologies are also introduced. The book will provide readers involved in the study

  12. AB Space Engine

    OpenAIRE

    Bolonkin, Alexander

    2008-01-01

    On 4 January 2007 the author published the article Wireless Transfer of Electricity in Outer Space in http://arxiv.org wherein he offered and researched a new revolutionary method of transferring electric energy in space. In that same article, he offered a new engine which produces a large thrust without throwing away large amounts of reaction mass (unlike the conventional rocket engine). In the current article, the author develops the theory of this kind of impulse engine and computes a samp...

  13. Cell Factory Engineering

    DEFF Research Database (Denmark)

    Davy, Anne Mathilde; Kildegaard, Helene Faustrup; Andersen, Mikael Rørdam

    2017-01-01

    focused on individual strategies or cell types, but collectively they fall under the broad umbrella of a growing field known as cell factory engineering. Here we condense >130 reviews and key studies in the art into a meta-review of cell factory engineering. We identified 33 generic strategies......-review provides general strategy guides for the broad range of applications of rational engineering of cell factories....

  14. Mechanical engineers data handbook

    CERN Document Server

    Carvill, James

    1994-01-01

    This text provides the student and professional mechanical engineer with a reference text of an essentially practical nature. It is uncluttered by text, and extensive use of illustrations and tables provide quick and clear access to information. It alsoincludes examples of detailed calculations on many of the applications of technology used by mechanical and production engineers, draughtsmen and engineering designers.Although mainly intended for those studying and practising mechanical engineering, a glance at the contents will show that it is also useful to those in related br

  15. Computer aided control engineering

    DEFF Research Database (Denmark)

    Szymkat, Maciej; Ravn, Ole

    1997-01-01

    Current developments in the field of Computer Aided Control Engineering (CACE) have a visible impact on the design methodologies and the structure of the software tools supporting them. Today control engineers has at their disposal libraries, packages or programming environments that may be speci......Current developments in the field of Computer Aided Control Engineering (CACE) have a visible impact on the design methodologies and the structure of the software tools supporting them. Today control engineers has at their disposal libraries, packages or programming environments that may...

  16. Strain-engineered MOSFETs

    CERN Document Server

    Maiti, CK

    2012-01-01

    Currently strain engineering is the main technique used to enhance the performance of advanced silicon-based metal-oxide-semiconductor field-effect transistors (MOSFETs). Written from an engineering application standpoint, Strain-Engineered MOSFETs introduces promising strain techniques to fabricate strain-engineered MOSFETs and to methods to assess the applications of these techniques. The book provides the background and physical insight needed to understand new and future developments in the modeling and design of n- and p-MOSFETs at nanoscale. This book focuses on recent developments in st

  17. Stone cladding engineering

    National Research Council Canada - National Science Library

    Camposinhos, Rui de Sousa

    2014-01-01

    ...) for the most commonly used modern anchorage systems. Calculation examples allow designers to solve several anchorage engineering problems in a detailed and objective manner, underlining the key parameters...

  18. Geothermal reservoir engineering

    CERN Document Server

    Grant, Malcolm Alister

    2011-01-01

    As nations alike struggle to diversify and secure their power portfolios, geothermal energy, the essentially limitless heat emanating from the earth itself, is being harnessed at an unprecedented rate.  For the last 25 years, engineers around the world tasked with taming this raw power have used Geothermal Reservoir Engineering as both a training manual and a professional reference.  This long-awaited second edition of Geothermal Reservoir Engineering is a practical guide to the issues and tasks geothermal engineers encounter in the course of their daily jobs. The bo

  19. Stirling Engine Heat Pump

    Science.gov (United States)

    Kagawa, Noboru

    Recent advances in the feasibility studies related to the Stirling engines and Stirling engine heat pumps which have been considered attractive due to their promising role in helping to solve the global environmental and energy problems,are reviewed. This article begins to describe the brief history of the Stirling engines and theoretical thermodynamic analysis of the Stirling cycle in order to understand several advantages on the Stirling engine. Furthermore,they could throw light on our question why the dream engines had not been promoted to practical applications during two hundred years. The present review shows that the Stirling engines with several unique advantages including 30 to 40% thermal efficiency and preferable exhaust characteristics,had been designed and constructed by recent tackling for the development of the advanced automobile and other applications using them. Based on the current state of art,it is being provided to push the Stirling engines combined with heat pumps based on the reversed Rankine cycle to the market. At present,however, many problems, especially for the durability, cost, and delicate engine parts must be enforced to solve. In addition,there are some possibilities which can increase the attractiveness of the Stirling engines and heat pumps. The review closes with suggestions for further research.

  20. Internal combustion piston engines

    Energy Technology Data Exchange (ETDEWEB)

    Segaser, C.L.

    1977-07-01

    Current worldwide production of internal combustion piston engines includes many diversified types of designs and a very broad range of sizes. Engine sizes range from a few horsepower in small mobile units to over 40,000 brake horsepower in large stationary and marine units. The key characteristics of internal combustion piston engines considered appropriate for use as prime movers in Integrated Community Energy Systems (ICES) are evaluated. The categories of engines considered include spark-ignition gas engines, compression-ignition oil (diesel) engines, and dual-fuel engines. The engines are evaluated with respect to full-load and part-load performance characteristics, reliability, environmental concerns, estimated 1976 cost data, and current and future status of development. The largest internal combustion piston engines manufactured in the United States range up to 13,540 rated brake horsepower. Future development efforts are anticipated to result in a 20 to 25% increase in brake horsepower without increase in or loss of weight, economy, reliability, or life expectancy, predicated on a simple extension of current development trends.

  1. Journal of transportation engineering

    National Research Council Canada - National Science Library

    1983-01-01

    The Journal of Transportation Engineering contains technical and professional articles on the planning, design, construction, maintenance, and operation of air, highway, rail, and urban transportation...

  2. Cyber-Informed Engineering

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, Robert S. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Benjamin, Jacob [Idaho National Lab. (INL), Idaho Falls, ID (United States); Wright, Virginia L. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Quinones, Luis [Idaho National Lab. (INL), Idaho Falls, ID (United States); Paz, Jonathan [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2017-03-01

    A continuing challenge for engineers who utilize digital systems is to understand the impact of cyber-attacks across the entire product and program lifecycle. This is a challenge due to the evolving nature of cyber threats that may impact the design, development, deployment, and operational phases of all systems. Cyber Informed Engineering is the process by which engineers are made aware of both how to use their engineering knowledge to positively impact the cyber security in the processes by which they architect and design components and the services and security of the components themselves.

  3. Bio Engineering Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — Description/History: Chemistry and biology laboratoriesThe Bio Engineering Laboratory (BeL) is theonly full spectrum biotechnology capability within the Department...

  4. The Quantum Engineering Conundrum

    Science.gov (United States)

    Monroe, Christopher

    2017-04-01

    There is newfound rush and excitement in Quantum Information Science, as this field seems to be moving toward an industrial/engineering phase. However, this evolution will require that quantum science, long the domain of academics and other researchers, make the leap to sustained engineering efforts in order to fabricate practical devices. I will address the conundrum, that full-blooded engineering does not generally happen on campuses, while many in the professional engineering and computer science community do not believe in quantum physics!

  5. Biomedical Engineering Desk Reference

    CERN Document Server

    Ratner, Buddy D; Schoen, Frederick J; Lemons, Jack E; Dyro, Joseph; Martinsen, Orjan G; Kyle, Richard; Preim, Bernhard; Bartz, Dirk; Grimnes, Sverre; Vallero, Daniel; Semmlow, John; Murray, W Bosseau; Perez, Reinaldo; Bankman, Isaac; Dunn, Stanley; Ikada, Yoshito; Moghe, Prabhas V; Constantinides, Alkis

    2009-01-01

    A one-stop Desk Reference, for Biomedical Engineers involved in the ever expanding and very fast moving area; this is a book that will not gather dust on the shelf. It brings together the essential professional reference content from leading international contributors in the biomedical engineering field. Material covers a broad range of topics including: Biomechanics and Biomaterials; Tissue Engineering; and Biosignal Processing* A hard-working desk reference providing all the essential material needed by biomedical and clinical engineers on a day-to-day basis * Fundamentals, key techniques,

  6. Engine and method for operating an engine

    Science.gov (United States)

    Lauper, Jr., John Christian; Willi, Martin Leo [Dunlap, IL; Thirunavukarasu, Balamurugesh [Peoria, IL; Gong, Weidong [Dunlap, IL

    2008-12-23

    A method of operating an engine is provided. The method may include supplying a combustible combination of reactants to a combustion chamber of the engine, which may include supplying a first hydrocarbon fuel, hydrogen fuel, and a second hydrocarbon fuel to the combustion chamber. Supplying the second hydrocarbon fuel to the combustion chamber may include at least one of supplying at least a portion of the second hydrocarbon fuel from an outlet port that discharges into an intake system of the engine and supplying at least a portion of the second hydrocarbon fuel from an outlet port that discharges into the combustion chamber. Additionally, the method may include combusting the combustible combination of reactants in the combustion chamber.

  7. Do we educate engineers that can engineer?

    DEFF Research Database (Denmark)

    Nyborg, Mads; Probst, Christian W.

    2017-01-01

    Since 2008, the Bachelor of Engineering education at the Technical University of Denmark has been CDIO-based, including the software technology and IT and economics study lines. Consequently, the study plans of these study lines were revised to include cross-disciplinary CDIO projects in each...... a survey to provide us with insights for improving our study lines and to address the question: “Are we educating engineers who can engineer?” The questionnaire is aligned with the CDIO syllabus and can also serve for surveying other study lines, since it is not study line specific. To obtain meaningful...... of the first four semesters. These projects replaced 11 smaller, course-specific projects in the old study plans. The first three semesters contain design-build projects spanning several courses, and the fourth semester centers around a stand-alone CDIO project. These team-based projects aim at training...

  8. Perturbing engine performance measurements to determine optimal engine control settings

    Science.gov (United States)

    Jiang, Li; Lee, Donghoon; Yilmaz, Hakan; Stefanopoulou, Anna

    2014-12-30

    Methods and systems for optimizing a performance of a vehicle engine are provided. The method includes determining an initial value for a first engine control parameter based on one or more detected operating conditions of the vehicle engine, determining a value of an engine performance variable, and artificially perturbing the determined value of the engine performance variable. The initial value for the first engine control parameter is then adjusted based on the perturbed engine performance variable causing the engine performance variable to approach a target engine performance variable. Operation of the vehicle engine is controlled based on the adjusted initial value for the first engine control parameter. These acts are repeated until the engine performance variable approaches the target engine performance variable.

  9. Fabrication and Evaluation of Electrospun, 3D-Bioplotted, and Combination of Electrospun/3D-Bioplotted Scaffolds for Tissue Engineering Applications

    Directory of Open Access Journals (Sweden)

    Liliana F. Mellor

    2017-01-01

    Full Text Available Electrospun scaffolds provide a dense framework of nanofibers with pore sizes and fiber diameters that closely resemble the architecture of native extracellular matrix. However, it generates limited three-dimensional structures of relevant physiological thicknesses. 3D printing allows digitally controlled fabrication of three-dimensional single/multimaterial constructs with precisely ordered fiber and pore architecture in a single build. However, this approach generally lacks the ability to achieve submicron resolution features to mimic native tissue. The goal of this study was to fabricate and evaluate 3D printed, electrospun, and combination of 3D printed/electrospun scaffolds to mimic the native architecture of heterogeneous tissue. We assessed their ability to support viability and proliferation of human adipose derived stem cells (hASC. Cells had increased proliferation and high viability over 21 days on all scaffolds. We further tested implantation of stacked-electrospun scaffold versus combined electrospun/3D scaffold on a cadaveric pig knee model and found that stacked-electrospun scaffold easily delaminated during implantation while the combined scaffold was easier to implant. Our approach combining these two commonly used scaffold fabrication technologies allows for the creation of a scaffold with more close resemblance to heterogeneous tissue architecture, holding great potential for tissue engineering and regenerative medicine applications of osteochondral tissue and other heterogeneous tissues.

  10. Systems Engineering and Integration as a Foundation for Mission Engineering

    Science.gov (United States)

    2015-09-01

    Systems Engineering ( INCOSE ). 2004. Systems Engineering Handbook . INCOSE -TP-2003-016-02. Version 2a. San Diego, CA: INCOSE ... Systems Engineering ( INCOSE ). 2004. Systems Engineering Handbook . INCOSE -TP-2003-016-02. Version 2a. San Diego, CA: INCOSE International Council on...International Council on Systems Engineering ( INCOSE ). 2015. “What is SE?” Accessed on July 10.

  11. 77 FR 9837 - Airworthiness Directives; Lycoming Engines Reciprocating Engines

    Science.gov (United States)

    2012-02-21

    ...; AD 2012-03-07] RIN 2120-AA64 Airworthiness Directives; Lycoming Engines Reciprocating Engines AGENCY... airworthiness directive (AD) for certain Lycoming Engines reciprocating engines. This AD was prompted by a... carburetor with one eligible for installation. We are issuing this AD to prevent engine in-flight shutdown...

  12. Manufacturing of hydrogel biomaterials with controlled mechanical properties for tissue engineering applications.

    Science.gov (United States)

    Vedadghavami, Armin; Minooei, Farnaz; Mohammadi, Mohammad Hossein; Khetani, Sultan; Rezaei Kolahchi, Ahmad; Mashayekhan, Shohreh; Sanati-Nezhad, Amir

    2017-10-15

    Hydrogels have been recognized as crucial biomaterials in the field of tissue engineering, regenerative medicine, and drug delivery applications due to their specific characteristics. These biomaterials benefit from retaining a large amount of water, effective mass transfer, similarity to natural tissues and the ability to form different shapes. However, having relatively poor mechanical properties is a limiting factor associated with hydrogel biomaterials. Controlling the biomechanical properties of hydrogels is of paramount importance. In this work, firstly, mechanical characteristics of hydrogels and methods employed for characterizing these properties are explored. Subsequently, the most common approaches used for tuning mechanical properties of hydrogels including but are not limited to, interpenetrating polymer networks, nanocomposites, self-assembly techniques, and co-polymerization are discussed. The performance of different techniques used for tuning biomechanical properties of hydrogels is further compared. Such techniques involve lithography techniques for replication of tissues with complex mechanical profiles; microfluidic techniques applicable for generating gradients of mechanical properties in hydrogel biomaterials for engineering complex human tissues like intervertebral discs, osteochondral tissues, blood vessels and skin layers; and electrospinning techniques for synthesis of hybrid hydrogels and highly ordered fibers with tunable mechanical and biological properties. We finally discuss future perspectives and challenges for controlling biomimetic hydrogel materials possessing proper biomechanical properties. Hydrogels biomaterials are essential constituting components of engineered tissues with the applications in regenerative medicine and drug delivery. The mechanical properties of hydrogels play crucial roles in regulating the interactions between cells and extracellular matrix and directing the cells phenotype and genotype. Despite

  13. Courseware Engineering Methodology.

    Science.gov (United States)

    Uden, Lorna

    2002-01-01

    Describes development of the Courseware Engineering Methodology (CEM), created to guide novices in designing effective courseware. Discusses CEM's four models: pedagogical (concerned with the courseware's pedagogical aspects), conceptual (dealing with software engineering), interface (relating to human-computer interaction), and hypermedia…

  14. Disciplinary Literacy in Engineering

    Science.gov (United States)

    Wilson-Lopez, Amy; Minichiello, Angela

    2017-01-01

    People who practice engineering can make a difference through designing products, procedures, and systems that improve people's quality of life. Literacy, including the interpretation, evaluation, critique, and production of texts and representations, is important throughout the engineering design process. In this commentary, the authors outline…

  15. Sustainability in Software Engineering

    NARCIS (Netherlands)

    Wolfram, N.J.E.; Lago, P.; Osborne, Francesco

    2017-01-01

    The intersection between software engineering research and issues related to sustainability and green IT has been the subject of increasing attention. In spite of that, we observe that sustainability is still not clearly defined, or understood, in the field of software engineering. This lack of

  16. Metaheuristics and engineering

    Science.gov (United States)

    Toklu, Y. Cengiz

    2013-10-01

    In this paper it is intended to present a general look to metaheuristic algorithms and their applications to engineering problems. An assessment is given of metaheuristic algorithms to emphasize their common characteristics. A short literature survey is presented showing engineering problems that are solved by metaheuristic algorithms. The advantages and disadvantages of these new techniques over classical method are discussed.

  17. Engineering Students' Sustainability Approaches

    Science.gov (United States)

    Haase, S.

    2014-01-01

    Sustainability issues are increasingly important in engineering work all over the world. This article explores systematic differences in self-assessed competencies, interests, importance, engagement and practices of newly enrolled engineering students in Denmark in relation to environmental and non-environmental sustainability issues. The…

  18. CDMA systems capacity engineering

    CERN Document Server

    Kim, Kiseon

    2004-01-01

    This new hands-on resource tackles capacity planning and engineering issues that are crucial to optimizing wireless communication systems performance. Going beyond the system physical level and investigating CDMA system capacity at the service level, this volume is the single-source for engineering and analyzing systems capacity and resources.

  19. Building Internet Search Engines

    Directory of Open Access Journals (Sweden)

    Mustafa Akgül

    1996-09-01

    Full Text Available Internet search engines are powerful tools to find electronics objects such as addresses of individuals and institutions, documents, statistics of all kinds, dictionaries, cata­logs, product information etc. This paper explains how to build and run some very common search engines on Unix platforms, so as to serve documents through the Web.

  20. Teaching Engineering Practices

    Science.gov (United States)

    Cunningham, Christine M.; Carlsen, William S.

    2014-01-01

    Engineering is featured prominently in the Next Generation Science Standards (NGSS) and related reform documents, but how its nature and methods are described is problematic. This paper is a systematic review and critique of that representation, and proposes that the disciplinary core ideas of engineering (as described in the NGSS) can be…